Chụp cộng hưởng từ (MRI) là một phương pháp chẩn đoán kết hợp với một nam châm lớn, tần số vô tuyến và máy tính để tạo ra hình ảnh chi tiết của các cơ quan trong cơ thể, trong đó có não và tuỷ sống. Để phát huy tác dụng của MRI cần lưu ý gì khi chụp MRI não và tủy sống? . Chụp MRI sọ não Chụp cộng hưởng từ (MRI) sọ não là phương pháp chẩn đoán hình ảnh dựa trên cơ chế hoạt động của từ trường. MRI đặc biệt hiệu quả trong những trường hợp chẩn đoán các tổn thương liên quan đến Não và tủy sống, bao gồm: Chứng phình động mạch não Bệnh đa xơ cứng Não úng thủy Đột quỵ Nhiễm trùng não Khối u não Xuất huyết não Rối loạn nội tiết tố dẫn đến một số bệnh như hội chứng Cushing. Chụp cộng hưởng từ sọ não còn có thể giúp xác định các tổn thương não do Chấn thương sọ não hoặc đột quỵ mang lại. Trong một số trường hợp, MRI có thể cung cấp hình ảnh rõ ràng về các phần của bộ não không thể nhìn thấy bằng Xquang, quét CT hoặc siêu âm. Chụp MRI đặc biệt có giá trị để chẩn đoán các vấn đề liên quan với tuyến yên và thân não. Ngoài ra các bác sĩ cũng có thể yêu cầu chụp MRI sọ não để hỗ trợ chẩn đoán một số triệu chứng sau: Mệt mỏi, hoa mắt, chóng mặt Co giật Rối loạn nhận thức hoặc rối loạn hành vi Chứng đau đầu kinh niên.
[ clinical commentary ] JAMES ELLIOTT, PT, PhD1 • TIMOTHY FLYNN, PT, PhD2 • AIMAN AL-NAJJAR, MSc3 JOEL PRESS, MD4 • BAO NGUYEN, MD5 • JON TIMOTHY NOTEBOOM, PT, PhD6 Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved The Pearls and Pitfalls of Magnetic Resonance Imaging for the Spine S ince its inception nearly 35 years ago, magnetic resonance imaging (MRI) of the human spine has become a widely used imaging modality in both the research and clinical arenas With excellent tissue contrast, it provides for a means of direct evaluation of the brain and spinal cord, spinal discs, ligaments, vertebral bodies, vascular structures, muscle tissues, and facet joints It also provides the only means of directly imaging intrinsic focal intrasubstance lesions, such as multiple sclerosis plaques, early edematous changes due to cord compression (compressive myelomalacia), transverse myelitis, or small cord tumors Information obtained from MRI sequences can be complementary to radiographic and computerized tomography (CT) exams and used to detect additional regions of osseous injury (eg, edema) or help, in some cases, to determine the precise location of structural bony damage or sinister pathology TTSYNOPSIS: Musculoskeletal imaging of the spine can be an invaluable tool to inform clinical decision making in patients with spinal pain An understanding of the technology involved in producing and interpreting high-resolution images produced from magnetic resonance imaging (MRI) of the human spine is necessary to better appreciate which sequences can be used for, or tailored to, individual patients and their conditions However, there is substantial variability in the clinical meaningfulness of some MRI findings of spinal tissues For example, normal variants can Neurologic deficits following traumatic spinal injury may call for the use of specific MRI sequences to detect potential nerve root avulsions52,95 or other posttraumatic sequelae (eg, syrinx and/ or cord tethering) Spinal canal and neuroforaminal compromise and cord compression are also well evaluated with MRI Ligamentous and soft tissue injuries are easily appreciated as focal areas of altered signal or as frank discontinuities in the ligaments themselves.9,45 MRI often mimic significant musculoskeletal pathology, which could increase the risk of misinformed clinical decisions and, even worse, poor or adverse outcomes This clinical commentary will highlight some of the pearls and pitfalls of MRI for the cervical, thoracic, and lumbar regions, and include cases to illustrate some of the common imaging artifacts and normal variants for MRI of the spine J Orthop Sports Phys Ther 2011;41(11):848-860 doi:10.2519/jospt.2011.3636 TTKEY WORDS: MRI, medical imaging, radiology, spinal pain, whiplash is also helpful in identifying associated secondary findings to spinal injury, such as altered muscle physiology and structure.1,35,37,38,40,62 In fact, innovative uses for advanced MRI applications may become particularly helpful in assessing the structure and function of spinal tissues (eg, muscles and intervertebral discs) and their physiological response to commonly prescribed physical therapy techniques.16,23,31,32,38,46,70 These will be discussed in more detail in the cervical, thoracic, and lumbar spine sections Emerging evidence highlights the usefulness of MRI in assessing clinical progression from time of diagnosis to functional recovery for patients with certain musculoskeletal conditions.25,46,70 Such information may be helpful in determining prognosis and response, or lack thereof, to conservative treatment.25,40,46 Despite these technological advances, the current economic costs associated with MRI may preclude the referral for, and performance of, serial MRI in current physical therapy clinical practice This clinical commentary will highlight the pearls and pitfalls of MRI for the cervical, thoracic, and lumbar regions Included will be cases to illustrate some of the common imaging artifacts and normal variants, as well as important information related to the expanding technology behind various research and Assistant Professor, Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL; Honorary Senior Fellow in the School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia 2Distinguished Professor, Rocky Mountain University School of Health Professions Provo, UT 3Radiographer, Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia Medical Director, Spine & Sports Rehabilitation Center, Rehabilitation Institute of Chicago and Professor, Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL 5Senior Musculoskeletal Radiologist, Envision Radiology, Lakewood, CO 6Professor, School of Physical Therapy, Reuckert-Hartman College of Health Profession, Regis University, Denver, CO Address correspondence Dr James M Elliott, Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, 645 N Michigan Avenue, Suite 1100, Chicago, IL 60540 E-mail: j-elliott@northwestern.edu 848 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 848 10/19/2011 5:39:04 PM clinically based MRI applications for the human spine MRI OF THE SPINE Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright â 2011 Journal of Orthopaedic & Sports Physical Therapyđ All rights reserved M RI of the spine remains an important clinical application, considering the high prevalence of spinal pain in the western world It is particularly helpful in ruling out serious spinal pathology While it is widely used for detecting anatomic pain producing abnormalities of spinal soft tissues, the overall diagnostic and prognostic value of routine investigations for many patients with spinal conditions has not been established The reasons for such discrepancies are many and include but are not limited to (1) low signal-to-noise ratio, which is the ratio of the average signal intensity over the standard deviation of the surrounding noise within the image, with lower values indicating poorer image quality, (2) image artifacts, (3) lack of normative data to compare with significant findings, (4) excessive referral for imaging of patients presenting with spinal pain, and (5) misinterpreting local spinal abnormalities as the source of patient complaints Despite the aforementioned pitfalls, emerging data suggest that specific spinal pain disorders may be categorized by imaging findings, as indicated by preliminary findings in healthy controls compared to those with traumatic neck pain and low back pain.15-17,36,41 Some Benefits of MRI When Compared to Radiography and CT of the Cervical Spine CERVICAL SPINE T the patient to ionizing radiation While most dosage levels would be considered appropriate per the clinical scenario, there is evidence to indicate that the current pattern of use of medical imaging in the United States among nonelderly patients exposes many to excessive and potentially dangerous radiation doses.43 As such, strategies for considering individual risks and benefits to ensure appropriate use of these procedures in the general population are warranted and necessary A feasible strategy would be to include in the medical record an estimate of patient-specific doses from previous examinations, to identify patients at risk for a high cumulative dose.43 Furthermore, to reduce the frequency and potential for increased radiation exposure of excessive imaging, the informed clinician may benefit from employing various clinical decision rules, such as the Canadian Cervical Spine Rules, for determining when standard radiography is required for the patient suspected of having a cervical spine fracture.87 At the very least, all practitioners involved in referral for imaging, including physical therapists, should refer to the excellent online resource (www.radiologyinfo.org) on radiation exposure in X ray and CT examinations made available from the collaborative effort between the Radiological Society of North America and the American College of Radiology he cervical spine is particularly vulnerable to traumatic events, such as falls, motor vehicle accidents, or sports injuries, with a number of tissues at risk CT scanning provides for a sensitive measure of bony fracture, with visualization in and dimensions, making it ideal as an initial screening modality for osseous spinal pathology in adults.18,19,21,48,74,90,99 As such, CT is warranted for individuals with a mechanism of injury known to increase risk for acute spinal fracture.68 However, CT exposes Compared to CT and radiography, MRI provides for the best evaluation of soft tissue pathology and, in essence, provides the only direct evaluation of the spinal cord.45 Images obtained of the vertebral discs, ligaments, hematomas, and the spinal cord are frequently complementary to the CT and radiographic evaluation of bony pathology.9,45 For example, a short-tau inversion-recovery sequence, an extremely important pulse sequence in musculoskeletal imaging of normal bone containing fatty marrow, FIGURE Cervical spine magnetic resonance imaging (sagittal view), revealing a transverse defect through the base of the odontoid (arrow), consistent with a fracture of the odontoid process Reproduced with permission from Ross et al.82 could provide additional information to highlight areas of undetected fractures, bone bruising, and tumors via fat suppression (also known as fatsat, fat saturation, or opposed-phase imaging) Other conventional MRI sequences can be also used to accurately identify fractures or the presence of other pathologies (eg, os odontoideum)71 when initial radiographs not allow for adequate interpretation (FIGURE 1)82 or they may have been missed during evaluation (FIGURE 2) There is also preliminary evidence which highlights the use of advanced imaging applications (eg, MR spectroscopy) to explore and quantify the metabolic environment of the spinal cord and brain in patients with varying spinal conditions with neurological compromise, such as myelopathy,59 chronic whiplash-related pain and disability,41 and fibromyalgia.102 While preliminary, such findings may prove clinically relevant, as the vast majority of these patients, despite ongoing pain and disability, rarely present with salient structural abnormalities on conventional imaging that are related to clinical signs and symptoms.77,78,81 Larger scaled prospective studies probing the chemical environment of the spinal cord and brain of patients with varying musculoskeletal conditions and comparing them with both conventional MRI and clinical exam findings are required be- journal of orthopaedic & sports physical therapy | volume 41 | number 11 | november 2011 | 849 41-11 Elliott.indd 849 10/19/2011 5:39:05 PM [ clinical commentary fore more definitive conclusions can be drawn The first author (J.E.) is currently investigating this in prospective fashion on patients with cervical spine trauma Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved Indications for MRI in Suspected Neurologic and/or Vascular Abnormalities MRI of the soft tissues in the cervical spine is traditionally indicated when a neurologic deficit is present or when there is clinical suspicion of a vascular abnormality following trauma Despite the rightful clinical concern for the presence of vascular complications in patients with neck pain, the accurate determination of patients at high risk of complications following physical therapy examination and treatment of the cervical spine is unknown and extremely difficult to estimate Moreover, there are contradictory results from blood flow studies in which the sensitivity (0%-29%) and specificity (9%-86%) of the commonly used vertebrobasilar insufficiency (VBI) test is quite variable.49,63,79 Accordingly, the use of the VBI test may not be supported by the available data On the contrary, current recommendations from the Manipulation Association of Chartered Physiotherapists in the United Kingdom suggest that consideration of atherosclerotic risk factors, in tandem with neurologic screening tests (eg, cranial nerve testing), may assist in identifying at-risk patients We encourage reading the excellent works by Kerry et al64 on this topic Such consideration of hemodynamic and neurologic functioning in patients with cervical disorders may help improve clinicians’ understanding of the risks and underlying mechanisms of vascular events, thus improve their ability to know when to refer the patient for further medical workup, which may include conventional and/or advanced vascular studies Standard imaging studies of the cervical spine would typically include axial T2-weighted images, which would allow for the identification of major intracranial flow voids in the carotid and vertebral arteries Vascular flow voids, which have a distinctive black appearance on FIGURE Sagittal T1-weighted magnetic resonance image Arrows point to area of os odontoideum and Klippel-Feil fusion Reproduced with permission from Mintken et al.71 T2-weighted images, are normal and considered a reliable clinical indicator of vessel patency Their presence can exclude the possibility of arterial dissection and/or occlusion An additional sequence may include the performance of a 3-D time-of-flight magnetic resonance angiography, which is frequently used to evaluate fast-flowing blood and to visualize small, tortuous vessels, such as those in the circle of Willis The advantages of such a sequence are its excellent signalto-noise ratio and the creation of a bright vascular image that does not require the invasive use of contrast media Regarding imaging in patients with neurologic deficits and spinal pain following trauma, as an alternative to myelography (a type of radiographic examination in which a contrast medium [dye] is injected into the dural sac surrounding the spinal cord and nerves to detect spinal cord pathology), high-resolution, heavily weighted T2 sequences can be used to detect potential nerve root avulsions and/or the abnormal collection of cerebrospinal fluid (eg, a pseudomeningocele) T2- and T1-weighted imaging is used to evaluate posttraumatic sequelae, such as myelomalacia, syrinx formation, cord tethering, and the development of muscular degeneration.9,35,40 In addition to imaging neurovascu- ] lar structures in patients with head and neck pain, there are available imaging techniques to document suspected ligamentous disruption Such investigations of cases involving traumatic accelerationdeceleration injuries (eg, whiplash) have documented previously unidentified upper cervical ligamentous disruption on high-resolution proton density-weighted (PD) MRI sequences.61,66,96 Such findings of increased signal intensity (bright) in the ligaments (alar, transverse, and tectorial membrane) have been proposed to be a factor in the development of chronic symptoms following cervical spine trauma Though not typically considered a part of standard imaging protocols for the cervical spine, the upper cervical ligaments can be easily visualized by specifically requesting high-resolution sagittal, axial, and coronal PD MRI of the craniocervical junction (CCJ).66 While the detection of ligamentous lesions in CCJ, which have been considered a potential contributor of persistent symptoms following whiplash injury,61,66,96 is possible, the prognostic value of such findings on PD imaging and its relation to clinical exam findings in patients with traumatic whiplash injury has been broadly refuted.33,69,72,73 For example, recent observations have detailed the presence of signal intensity changes of the CCJ ligaments in patients with nontraumatic neck disorders and in those with no history of neck pain.72 Thus, while it would be attractive to assign upper cervical ligament disruption on PD MRI to be the direct result of whiplash-related trauma, as well as the production (and possibly maintenance) of painful symptoms, this has not yet been distinguished from a normal variant.73 Therefore, the argument for the relevance of upper cervical spine ligament disruption in patients with traumatic whiplash measured by high-resolution PD MRI is poor Pearls • T he structure and integrity of the upper cervical ligaments can be visualized with high-resolution PD-weighted 850 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 850 10/19/2011 5:39:07 PM MRI Nonetheless, there is a paucity of available evidence to suggest that these patients should not receive conservative rehabilitative care Judicious monitoring of those with suspected ligamentous injuries is, however, warranted • Flow voids can reliably exclude the possibility of arterial occlusion and dissection Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapyđ All rights reserved Pitfalls ã F indings of CCJ ligamentous disruption, at present, not appear to be a unique feature of traumatic neck injuries Accordingly, MRI of the CCJ to identify ligamentous disruption is reported to be of limited prognostic value in the initial examination and followup of patients with whiplash (Quebec Task Force grades and 2).86 As such, its use is not recommended if attempting to establish a prognosis for these patients 97 THORACIC SPINE A lthough reported musculoskeletal injuries to the thoracic spine region have a much lower incidence rate compared to those of either the cervical or lumbar regions, there are acute and chronic conditions of the thoracic spine in which imaging findings may assist in the clinical diagnosis and potentially decision making for the physical therapist Similar to the cervical and lumbar regions for example, the thoracic disc is capable of nociception While the thoracic disc can be readily observed with MRI, the presence of disc pathology on structural imaging studies of the thoracic region does not automatically implicate the disc as a source of nociception Wood and colleagues demonstrated that the incidence of asymptomatic thoracic disk protrusions as observed on MRI is approximately 37%.101 Reports from a 2-year follow-up study showed little change in the size of the protrusions, suggesting that such structural disc abnormalities remain asymptomatic and exhibit little morpho- FIGURE MR images obtained in a 76-year-old woman with acute collapse of the fourth lumbar vertebral body because of osteoporosis (A) Sagittal T1-weighted spin echo image shows complete hypointensity in the vertebral body (B) Sagittal STIR image shows diffuse hyperintensity in the fractured vertebral body because of bone marrow edema Anteriorly and adjacent to the fractured superior end plate, a linear area of hyperintensity, isointense to cerebrospinal fluid, can be delineated on the STIR image This represents the fluid sign (arrow) Abbreviation: STIR, short-tau inversion recovery Reproduced with permission from Baur et al.13 metrical change over time.100 As such, the authors advised that clinicians should interpret the MRI findings of herniated discs in the thoracic region with caution Although descriptive in nature, the literature suggests a link between thoracic disc herniations and thoracic and chest wall pain.88 However, there remains little information for accurately identifying the pain referral pattern for the thoracic disc, and we are unaware of any specific clinical features that could differentiate pain arising from the disc from that of other structures in the thoracic region Theoretically, a physical therapist may infrequently encounter patients with acute blunt trauma to the thoracic spine that may require a referral for imaging studies However, in a changing healthcare environment, in which physical therapists are increasingly providing direct-access services, the opportunity exists for making frontline clinical decisions (including imaging referral) of such patients suspected of having bony injury (fracture) to the thoracic region As such, it is important to understand that fractures to the thoracic spine can and occur For example, at risk for fracture are patients with acute and/or chronic osteoporosis and also those with a history of metastatic diseases who may seek physical therapy care for functional impairments related to dysfunction of the thoracic region Radiological diagnoses of osteoporotic and metastatic fractures are usually straightforward, either on plain radiography or by applying a T1-weighted MRI sequence Despite the relative ease of diagnosing such fractures, the prevalence of false-negatives is reported to be high, with up to 45% going undetected Accordingly, a semi-quantitative assess- journal of orthopaedic & sports physical therapy | volume 41 | number 11 | november 2011 | 851 41-11 Elliott.indd 851 10/19/2011 5:39:08 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved [ clinical commentary ment tool to differentiate fractures from nonfracture deformities is available and known as the spinal fracture index (SFI).47 However, there are limitations to any grading system, including the SFI, with respect to anatomical variations such as normal wedging of the midthoracic and thoracolumbar vertebrae Such variations may cause overestimation Accordingly, baseline and serial radiographs could be performed and evaluated to detect morphometrical changes over time, in tandem with clinical signs/symptoms In comparison to radiographic evaluation, MRI has shown accuracy in the differential diagnosis of osteoporotic versus metastatic fracture by using either diffusion-weighted imaging10 (bone marrow is hypointense [dark] in the acute benign collapse and hyperintense [bright] in fractures secondary to metastatic tumors) or criteria related to the morphometrical features of the fracture, known as the “fluid sign.”13 The fluid sign, suggestive of bone marrow edema, has been a common feature of acute osteoporotic vertebral compression fractures in which bone marrow has been displaced This is rarely the case with fractures secondary to metastases.13 Specifically, the entire vertebral body may appear dark on T1-weighted images and bright on short-tau inversionrecovery images, due to the nulling of signal from fatty tissue, in the acute phase of osteoporotic fracture (FIGURE 3) Baur et al concluded that the fluid sign, while not to be used to definitively exclude metastatic tumors, may be regarded an additional morphological feature of the benign osteoporotic acute fracture.10,13 Clearly, an understanding of the MRI and what each imaging sequence depicts of such bony involvement would be useful for the physical therapist who would avoid mobilization over bony areas of the thoracic spine that might be weakened or compromised secondary to disease processes and/or advancing osteoporosis.14,44,83 While not common, a physical therapist may also encounter patients following acute trauma to the thoracolumbar region.29,30,67,85,89 Because up to 50% of ] FIGURE Sagittal T2-weighted magnetic resonance image of the thoracic spine demonstrating cerebrospinal fluid pulsation in the midthoracic region (circle) these patients can have associated neurological involvement, guidelines for using CT and MRI to identify the extent of thoracolumbar fractures and corresponding neurological damage have been explored and developed.30 Similar to imaging of the CCJ, MRI is capable of detecting ligamentous injury, especially that of the posterior ligamentous complex (PLC)—comprised of the posterior longitudinal ligament, facet joint capsule, ligamentum flavum, and interspinous and supraspinous ligaments—in thoracolumbar burst fractures However, ligamentous injury as shown by MRI has not been shown to correlate with the patient’s neurological function or fracture severity As such, Diaz et al30 concluded that MRI findings of PLC disruption are of little prognostic value in treatment planning of thoracolumbar burst fractures and, therefore, its routine use for excluding occult ligamentous injury is not altogether warranted These findings are consistent with those from Rihn et al,80 who concluded that the relatively low positive predictive value and specificity for MRI in assessing PLC integrity suggests a tendency to overdiag- FIGURE Sagittal T2-weighted magnetic resonance image demonstrating dephasing artifact in a rare intradural fusiform-shaped cyst, causing anterior displacement of the lower thoracic cord and descending nerve roots (circle) nose PLC disruption A Common Artifact in Thoracic Spine MRI Studies A challenge for the untrained professional viewing thoracic spine MRI studies are signal voids (dark spots) in the dorsal subarachnoid space, which may confound interpretation.42 Normal cerebrospinal fluid (CSF) has inherent MRI properties of low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences However, the normal CSF signal is frequently altered by superimposed flow phenomena, resulting in the aforementioned signal voids, which can result in flow-related artifacts Such artifacts can be subdivided into categories: time-offlight (TOF) effects and turbulent flow TOF loss is seen primarily on T2weighted spin echo and fast spin echo 852 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 852 10/19/2011 5:39:10 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved sequences, due to the fact that protons in CSF not experience both the initial π/2 (90°) radiofrequency pulse or the subsequent π (180°) refocusing pulse TOF presents as a dark signal in the dorsal subarachnoid space with faster proton velocity, thin slices, and long echo time (TE) Moreover, TOF loss of signal occurs when the imaging plane is perpendicular to the flow A common solution for reducing the occurrence of such artifact is to request the performance of a gradient echo sequence (GRE), which helps to eliminate TOF loss due to the use of a short echo time (TE) and no refocusing (180°) pulse Turbulent flow, or CSF pulsation artifact, causes significant dorsal dephasing artifacts in the central spinal canal, particularly in thoracic studies These artifacts can simulate a tumor or dural arteriovenous fistula (AVF) in the spinal canal FIGURE highlights dorsal dephasing artifacts in a thoracic study and FIGURE reveals dephasing artifacts in the thoracolumbar spine Pearls FIGURE Sagittal T2-weighted magnetic resonance image demonstrating grade spondylolisthesis in a 32-year-old asymptomatic female Reproduced with permission from Elliott et al.39 • T horacic spine tissues, such as the intervertebral disc, can generate nociceptive afferent input to the sensory system • Conventional MRI can visualize such soft tissue pathology • Nonoperative management is usually effective.22 • Gradient echo sequences help to eliminate artifacts such as TOF loss due to the use of a short TE thoracic region with caution, and association with clinical signs/symptoms is required • Similar to imaging of the CCJ, MRI can be used to identify clinical presence of ligamentous disruption; but the value of such findings with regards to treatment planning have not been well established Pitfalls LUMBAR SPINE • S imilar to the cervical and lumbar regions, a large proportion of these cases demonstrating structural disc pathology on MRI are asymptomatic, and longitudinal data indicate that they remain asymptomatic over time.100 In addition, nearly 30% of individuals with MRI findings of herniated thoracic discs may have cord compression but remain symptom free As such, the practitioner should interpret the findings of anatomical disc pathology in the A great clinical concern when imaging the lumbar spine is whether findings of anatomic structural pathology are appropriately correlated to the patient’s symptoms Compounding this issue are numerous studies that have shown a high prevalence of abnormal MRI findings among healthy asymptomatic volunteers without a history of low back pain.84 Sheehan84 concludes that the value of MRI in simple low back pain has not been established in the absence of red flags For example, among asymptomatic persons 60 years or older, 36% had a herniated disc, 21% had spinal stenosis, and more than 90% had a degenerated or bulging disc.20 Carragee et al24 in a prospective study found that among patients with lumbar imaging abnormalities before the onset of low back pain, 84% had unchanged or improved findings after symptoms developed.24 Furthermore, the use of MRI versus a lumbar radiograph early in the course of an episode of LBP resulted in a 3-fold increase in surgical rates, with no improvements in outcomes in the subsequent year.60 Notwithstanding the number of false positives, the image resolution of conventional MRI can be useful in examining the morphology of several anatomical structures, including the intervertebral disc, nerve roots, contents of the central canal/foramina, and facet joints In fact, MRI is the preferred imaging technique for confirming suspected lumbar disc herniation,50 nerve root entrapment, and spinal canal stenosis.84 Newer MRI units allow for upright imaging in positions that may better identify patient-specific symptoms compared to traditional units that require the patient to lie supine during the exam A case example may be the patient with spinal stenosis, in whom postures corresponding to altered symptoms can be more clearly observed in a standing versus supine position However, even with these advances the fact remains that pathological findings from many of the traditional anatomical structures typically assessed with imaging have not consistently proved helpful in the diagnostic, prognostic, and management planning for many of the patients seen in physical therapy settings As an additional example from a single case, FIGURE highlights a 32-year-old pregnant female with asymptomatic grade spondylolisthesis This particular patient, fully aware of the structural condition of her lumbar spine, which resulted from a fall injury at the age of years, under- journal of orthopaedic & sports physical therapy | volume 41 | number 11 | november 2011 | 853 41-11 Elliott.indd 853 10/19/2011 5:39:12 PM [ TABLE clinical commentary The Appearance of Common Imaging Artifacts, Remedies, and the Potential Penalties When Attempting to Resolve Them Appearance Time of flight loss A Priori Remedy Protons don’t experience both radiofrequency Use short TE technique, such as true fast pulses or the subsequent refocusing pulse, which leads to dark signal Turbulent flow ] Signal loss due to rapid dephasing, caused by varied spin velocities and directions Penalty Figure Less resolution FIGURE Lower SNR FIGURE imaging with steady-state precession, thicker slices, and image parallel to flow Use shorter TE scans and smaller voxels (thinner slice or larger FOV) B0 inhomogeneity Variation of signal intensity across the image Optimize shim and post correct the images RF inhomogeneity Variation in signal intensity Ensure that there is no RF shielding from FIGURE T2 contrast is reduced Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved nonferromagnetic objects and use a proper coil Susceptibility Different susceptibilities cause spatial distortion Chemical shift Use spin echo, shorter TE, and remove metal if possible Black border at fat-water interfaces, and bright border on the opposite side Use a smaller FOV and a wider bandwidth Lowered SNR, potential problem FIGURES 8, and fat suppression when imaging at with minimum TE and higher fields (3T and above) This will resolution reduce the separation of signal from fat and water (eg, a signal void) Aliasing or wraparound The region outside the FOV projects onto the other side of the image Partial volume A black border will result at the water-fat interface when out of phase Enlarge FOV, use phase oversampling; use Lose resolution FIGURE 10 Decreased SNR and potential FIGURE 11 surface coil Use spin echo sequences; in gradient echo sequences, optimize TE until water/fat contrast problems is in phase; use smaller voxel Abbreviations: FOV, field of view; RF, radiofrequency; SNR, signal-to-noise ratio; TE, echo time; TOF, time of flight went conventional MRI of the lumbar spine to make informed decisions related to expectant management of her first child It is noted, however, that the presence of high-grade spondylolisthesis does not necessarily indicate an increased risk of complications with childbirth Notwithstanding, the outcome in this single case was delivery of a healthy baby via caesarean section, without any negative consequences for the mother.39 While surgical arthrodesis can provide positive results for the patient with a painful grade to spondylolisthesis, conservative rehabilitation has also shown benefit for many.51 As such, clinical decisions to pursue surgical arthrodesis, based solely on imaging findings of structural pathology, is simply inappropriate Emerging Evidence in Support of Advanced Imaging Findings of the Lumbar Spine Laboratory and clinical investigations with imaging applications have expanded towards identifying and quantifying abnormal findings of soft tissue pathology, including histological and morphological changes of paraspinal tissues in subjects with and without spinal pain.34-37 Such investigations, using both structural and advanced imaging sequences, have demonstrated changes in the structure and function of the deep and superficial lumbar muscles (multifidus, transverse abdominis, and erector spinae group) with ultrasound, CT, and MRI.28,32,55-57,65 Kader et al62 have demonstrated a correlation between leg pain and MRI findings of increased atrophy and fatty infiltration of the ipsilateral lumbar multifidus, and others have demonstrated delayed and reduced recruitment of paraspinal muscles in response to functional tasks in patients with low back pain.32,53,57,92 These findings have formed the foundation for clinical interventions that have shown to reduce painful symptoms.26,53,75 Further evidence is also emerging to help reduce practice variability by assisting the clinician in determining which patient is likely to benefit from specific exercises.54 The current available evidence suggests that alterations in paraspinal muscle structure and function may be important with respect to clinical assessment and, as such, the evaluation for and interpretation of such findings could become a standard request when referring for imaging However, an unresolved issue remains the determination of the exact peripheral and/or central mechanisms behind paraspinal muscular alterations and their precise impact on the generation and/or maintenance of spinal pain As such, further research to determine the mechanisms and clinical relevance of such findings is required and currently underway in many laboratories It remains plausible that the biologic consequence of pain may manifest as an immediate alteration in motor control 854 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 854 10/19/2011 5:39:13 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved FIGURE A large amount of nonferromagnetic metal dental work in the mouth The metal shields the regions near the mouth from the radiofrequency pulses, producing a signal void on both (A) sagittal T1-weighted and (B) T2-weighted magnetic resonance images strategies in some patients, which, in turn, may contribute to the attendant muscle changes (atrophy and fatty infiltrates) and, quite possibly, changes in cortical functioning.4-8,91-94 An exquisite laboratory method to investigate the immediate influence of pain on the paraspinal muscle system functioning suggests this is so.31 Such investigation has provided preliminary evidence that the muscular response to such induced pain can be directly measured with muscle functional MRI (mfMRI).31 While exciting, we must caution that mfMRI techniques (at present) not yet appear to extend beyond the laboratory setting Another exciting area of investigation using advanced MRI techniques is that of diffusion-weighted imaging (DWI) In particular, the use of DWI for mapping intervertebral disc diffusion in response to commonly prescribed physical therapy interventions for patients with discogenic symptoms Beattie and colleagues have used DWI to study the relationship of diffusion within normal and degenerative discs that has resulted in some interesting observations.15,16 For example, DWI was used to compare the change in diffusion in lumbar discs between testing conditions: (1) lumbar joint mobilizations (posterior-to-anterior–directed pressures to the low back) and (2) prone lying Following joint mobilization, subjects had significant increases in diffusion within the degenerative discs at L5-S1 using DWI, whereas the subjects who engaged in prone lying demonstrated no changes in disc diffusion Such findings suggest that lumbar joint mobilizations may play a role in increasing diffusional properties within degenerative discs of the lumbar region A follow-up study demonstrated that lumbar joint mobilization, followed by prone press-ups, facilitated increased diffusion and significant reduction in pain (greater than 2/10 on a visual analog scale) These findings suggest a relationship between DWI findings of increased diffusion of the intervertebral disc and symptoms of discogenic low back pain and may help to identify a mechanism by which analgesia occurs following a commonly used intervention in physical therapy.15 The use of DWI in the spine also extends beyond quantifying the physiologic response in the intervertebral discs to treatments, as in evidence of its use in differentiating the following: (1) osteoporotic and metastatic vertebral body fractures,11,12,27,76 (2) degeneration versus infectious abnormalities of the vertebral end plate,34 (3) identification of nerve root compression,2,3,17,103 and (4) diffusional properties of water in the spinal musculature of healthy participants and those with spinal pain.36,41,58,104 Accordingly, DWI represents an innovative imaging application to quantify the precise movement of water within a variety of soft tissues that can be used to measure the physiological effects of disease and/or trauma As such, it is fast becoming a potentially valuable clinical tool to study cellular level responses to conservative management strategies commonly delivered by physicians and physical therapists (eg, injections, manual therapy, exercise, and physical agents) Despite the rapid advances in laboratory and clinical measures with MRI, every clinician should remain skeptical of the significance of MRI findings of structural pathology alone Specifically, all findings need to be interpreted within the context of the patient’s history, physical examination, and presentation before more informed clinical decisions can be made with confidence Pearls • C onventional MRI is the preferred imaging technique for confirming suspected lumbar disc herniation,50 nerve root entrapment, and spinal canal stenosis • Emerging research on muscle morphology and diffusional properties of soft tissues is providing new insights into the mechanisms underlying response to pain, as well as conservative treatments in patients with low back pain Pitfalls • T he rate of false-positive imaging in the lumbar spine is substantial Anatomic abnormalities have demonstrated a poor correlation with patient symptoms and may lead to increased surgical rates without improved outcomes ARTIFACTS F inally, it may be helpful for the physical therapist to understand how artifacts can impact image production and the interpretation of musculoskeletal imaging of the spine with MRI An image artifact is any feature which appears in an image but does not exist in the original object being imaged It is sometimes the result of operator error but may journal of orthopaedic & sports physical therapy | volume 41 | number 11 | november 2011 | 855 41-11 Elliott.indd 855 10/19/2011 5:39:14 PM [ A Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved ] 16 000 Hz Frequency column clinical commentary 256 FIGURE Chemical shift artifact is displayed at the kidneys on coronal magnetic resonance imaging at T (arrows) 62.5 Hz F W –220 Hz B 32 000 Hz Frequency column 256 FIGURE 10 Axial T2-weighted magnetic resonance image of the head, demonstrating wraparound artifact secondary to a small field of view 125 Hz F W –220 Hz FIGURE (A) Chemical shift at 1.5 T with 16 000-Hz bandwidth (B) Chemical shift at 1.5 T with 32 000-Hz bandwidth Adapted with permission from Westbrook et al.98 also be the consequence of usual physiological processes of the human body, such as blood flow and/or CSF pulsation It is important to be familiar with the appearance of artifacts, as they can obscure, and oftentimes are mistaken as, structural pathology Therefore, image artifacts can result in an alarmingly high rate of false positives, which could have serious consequences regarding treatments rendered or withheld The TABLE summarizes a number of common image artifacts, the potential causes underlying their presence, and the potential penalties when attempting to resolve them FIGURES through 11 highlight the presence of some of these encountered artifacts in MRI FIGURE demonstrates how metal dental implants can produce a signal void (dark spots) when imaging the cervical spine FIGURES and present chemical shift artifact Chemical shift is a misregistration between the relative positions of fat and water The difference in chemical shift of water and fat-like hydrogens is approximately 3.5 parts per million, which at 1.5 T corresponds to a frequency difference of approximately 220 Hz That is, fat precesses at 220 Hz less than water In other words, at water proton resonance frequency, the fat will be shifted from its position in the frequency column (FIGURE 8A) Increasing the 856 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 856 10/19/2011 5:39:16 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved FIGURE 11 Partial volume comparison of magnetic resonance axial slices through the same location of the brain: (A) mm and (B) 10 mm Note the loss of resolution in the image taken from a 10-mm-thick slice in B Reproduced with permission from Hornak, JP The Basics of MRI Available at: http://www.cis.rit.edu/htbooks/ mri/ Interactive Learning Software; 2010 bandwidth, as illustrated in FIGURE 8B, will provide for a smaller separation of water and fat, as a larger frequency range can be mapped across the same number of frequency pixels (256) Thus the individual frequency range of each pixel increases, and so the 220-Hz difference in precessional frequency between fat and water is translated into a much smaller pixel shift.98 FIGURE demonstrates the appearance of chemical shift at the kidneys on a coronal magnetic resonance image on a 3-T scanner FIGURE 10 demonstrates a wraparound artifact that can occur when imaging in too small a field of view The obvious remedy is to simply enlarge the field of view; however, this may also influence image resolution Finally, FIGURE 11 illustrates a partial volume artifact in the brain, whereby a loss of contrast between adjacent tissues results from the use of a large slice thickness The partial volume effect is minimal with thin slice thickness and sufficiently high resolution CONCLUSION A basic knowledge of the principles for spinal MRI can improve the physical therapist decision making in the management of spinal disorders MR images must be interpreted and correlated with the clinical presentation to determine the best and most informed treatment options Artifacts may obscure anatomy and pathology or be confused and interpreted as pathology A priori methods are readily available to eliminate or reduce artifacts The creation of new and improved MRI systems, combined with new pulse sequences and higher field strengths, has great potential for improved diagnosis and plan of care development in musculoskeletal rehabilitation for patients with spinal pain t 10 11 12 13 14 REFERENCES A li I, Ulbricht C, McGregor AH Degeneration of the extensor muscle group in a surgical low back and leg pain population J Back Musculoskelet Rehabil 2011;24:23-30 http://dx.doi org/10.3233/BMR-2011-0271 Aota Y, Niwa T, Uesugi M, Yamashita T, Inoue T, Saito T The correlation of diffusion-weighted magnetic resonance imaging in cervical compression myelopathy with neurologic and radiologic severity Spine (Phila Pa 1976) 2008;33:814-820 http://dx.doi.org/10.1097/ BRS.0b013e318169505e Aota Y, Onari K, An HS, Yoshikawa K Dorsal root 15 16 17 ganglia morphologic features in patients with herniation of the nucleus pulposus: assessment using magnetic resonance myelography 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2002 Fritz RC, Domroese ME, Carter GT Physiological and anatomical basis of muscle magnetic resonance imaging Phys Med Rehabil Clin N Am 2005;16:1033-1051, x http://dx.doi org/10.1016/j.pmr.2005.08.004 Genant HK, Wu CY, van Kuijk C, Nevitt MC Vertebral fracture assessment using a semiquantitative technique J Bone Miner Res 1993;8:1137-1148 http://dx.doi.org/10.1002/ jbmr.5650080915 Grogan EL, Morris JA, Jr., Dittus RS, et al Cervical spine evaluation in urban trauma centers: lowering institutional costs and complications through helical CT scan J Am Coll Surg 2005;200:160-165 http://dx.doi.org/10.1016/j jamcollsurg.2004.10.019 Gross A, Chesworth B A case for evidencebased practice in manual therapy In: Boyling J, Jull G, eds Grieve’s Modern Manual Therapy Edinburgh, UK: Churchill Livingstone; 2005 Hancock MJ, Koes B, Ostelo R, Peul W Diagnostic accuracy of the clinical examination in identifying the level of herniation in patients with sciatica Spine (Phila Pa 1976) 2011;36:E712-719 http://dx.doi.org/10.1097/ BRS.0b013e3181ee7f78 Harris IE, Weinstein SL Long-term follow-up of patients with grade-III and IV spondylolisthesis Treatment with and without posterior fusion J Bone Joint Surg Am 1987;69:960-969 Hayashi N, Masumoto T, Abe O, Aoki S, Ohtomo K, Tajiri Y Accuracy of abnormal paraspinal muscle findings on contrast-enhanced MR images as indirect signs of unilateral cervical rootavulsion injury Radiology 2002;223:397-402 Hebert JJ, Koppenhaver SL, Magel JS, Fritz JM The relationship of transversus abdominis and lumbar multifidus activation and prognostic factors for clinical success with a stabilization exercise program: a cross-sectional study Arch Phys Med Rehabil 2010;91:78-85 http://dx.doi org/10.1016/j.apmr.2009.08.146 Hicks GE, Fritz JM, Delitto A, McGill SM Preliminary development of a clinical prediction rule for determining which patients with low back pain will respond to a stabilization exercise program Arch Phys Med Rehabil 2005;86:1753-1762 http://dx.doi.org/10.1016/j.apmr.2005.03.033 858 | november 2011 | volume 41 | number 11 | journal of orthopaedic & sports physical therapy 41-11 Elliott.indd 858 10/19/2011 5:39:18 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved 55 H ides J, Stanton W, Freke M, Wilson S, McMahon S, Richardson C MRI study of the size, symmetry and function of the trunk muscles among elite cricketers with and without low back pain Br J Sports Med 2008;42:809-813 http:// dx.doi.org/10.1136/bjsm.2007.044024 56 Hides JA, Richardson CA, Jull GA Magnetic resonance imaging and ultrasonography of the lumbar multifidus muscle Comparison of two different modalities Spine (Phila Pa 1976) 1995;20:54-58 57 Hodges PW, Richardson CA Feedforward contraction of transversus abdominis is not influenced by the direction of arm movement Exp Brain Res 1997;114:362-370 58 Holl N, Echaniz-Laguna A, Bierry G, et al Diffusion-weighted MRI of denervated muscle: a clinical and experimental study Skeletal Radiol 2008;37:1111-1117 http://dx.doi.org/10.1007/ s00256-008-0552-2 59 Holly LT, Freitas B, McArthur DL, Salamon N Proton magnetic resonance spectroscopy to evaluate spinal cord axonal injury in cervical spondylotic myelopathy J Neurosurg Spine 2009;10:194-200 http://dx.doi org/10.3171/2008.12.SPINE08367 60 Jarvik JG, Hollingworth W, Martin B, et al Rapid magnetic resonance imaging vs radiographs for patients with low back pain: a randomized controlled trial JAMA 2003;289:2810-2818 http:// dx.doi.org/10.1001/jama.289.21.2810 61 Kaale BR, Krakenes J, Albrektsen G, Wester K Whiplash-associated disorders impairment rating: neck disability index score according to severity of MRI findings of ligaments and membranes in the upper cervical spine J Neurotrauma 2005;22:466-475 http://dx.doi org/10.1089/neu.2005.22.466 62 Kader DF, Wardlaw D, Smith FW Correlation between the MRI changes in the lumbar multifidus muscles and leg pain Clin Radiol 2000;55:145149 http://dx.doi.org/10.1053/crad.1999.0340 63 Kerry R, Rushton A Decision theory in physical therapy World Confederation for Physical Therapy 14th International Congress Barcelona, Spain; 2003 64 Kerry R, Taylor AJ Cervical arterial dysfunction: knowledge and reasoning for manual physical therapists J Orthop Sports Phys Ther 2009;39:378-387 http://dx.doi.org/10.2519/ jospt.2009.2926 65 Kiesel KB, Uhl T, Underwood FB, Nitz AJ Rehabilitative ultrasound measurement of select trunk muscle activation during induced pain Man Ther 2008;13:132-138 http://dx.doi org/10.1016/j.math.2006.10.003 66 Krakenes J, Kaale BR Magnetic resonance imaging assessment of craniovertebral ligaments and membranes after whiplash trauma Spine (Phila Pa 1976) 2006;31:2820-2826 http:// dx.doi.org/10.1097/01.brs.0000245871.15696.1f 67 Lin CY, Fu JH, Li SC, Lai PH Surfer’s myelopathy QJM 2011;http://dx.doi.org/10.1093/qjmed/ hcr014 68 Looby S, Flanders A Spine trauma Radiol 69 70 71 72 73 74 75 76 77 78 79 80 Clin North Am 2011;49:129-163 http://dx.doi org/10.1016/j.rcl.2010.07.019 Maak TG, Tominaga Y, Panjabi MM, Ivancic PC Alar, transverse, and apical ligament strain due to head-turned rear impact Spine (Phila Pa 1976) 2006;31:632-638 http://dx.doi org/10.1097/01.brs.0000202739.05878.d3 McDonald CM, Carter GT, Fritz RC, Anderson MW, Abresch RT, Kilmer DD Magnetic resonance imaging of denervated muscle: comparison to electromyography Muscle Nerve 2000;23:1431-1434 Mintken PE, Metrick L, Flynn TW Upper cervical ligament testing in a patient with os odontoideum presenting with headaches J Orthop Sports Phys Ther 2008;38:465-475 http://dx.doi org/10.2519/jospt.2008.2747 Myran R, Kvistad KA, Nygaard OP, Andresen H, Folvik M, Zwart JA Magnetic resonance imaging assessment of the alar ligaments in whiplash injuries: a case-control study Spine (Phila Pa 1976) 2008;33:2012-2016 http://dx.doi org/10.1097/BRS.0b013e31817bb0bd Myran R, Zwart JA, Kvistad KA, et al Clinical characteristics, pain, and disability in relation to alar ligament MRI findings Spine (Phila Pa 1976) 2011;36:E862-867 http://dx.doi org/10.1097/BRS.0b013e3181ff1dde Nguyen GK, Clark R Adequacy of plain radiography in the diagnosis of cervical spine injuries Emerg Radiol 2005;11:158-161 http://dx.doi org/10.1007/s10140-004-0351-6 O’Sullivan PB, Phyty GD, Twomey LT, Allison GT Evaluation of specific stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolisthesis Spine (Phila Pa 1976) 1997;22:2959-2967 Oztekin O, Ozan E, Hilal Adibelli Z, Unal G, Abali Y SSH-EPI diffusion-weighted MR imaging of the spine with low b values: is it useful in differentiating malignant metastatic tumor infiltration from benign fracture edema? Skeletal Radiol 2009;38:651-658 http://dx.doi.org/10.1007/ s00256-009-0668-z Pettersson K, Hildingsson C, Toolanen G, Fagerlund M, Bjornebrink J Disc pathology after whiplash injury A prospective magnetic resonance imaging and clinical investigation Spine (Phila Pa 1976) 1997;22:283-287; discussion 288 Pettersson K, Hildingsson C, Toolanen G, Fagerlund M, Bjornebrink J MRI and neurology in acute whiplash trauma No correlation in prospective examination of 39 cases Acta Orthop Scand 1994;65:525-528 Richter R, Reinking M How does evidence on the diagnostic accuracy of the vertebral artery test influence teaching of a test in a professional physical therapist education program? Phys Ther 2005;85:588-599 Rihn JA, Fisher C, Harrop J, Morrison W, Yang N, Vaccaro AR Assessment of the posterior ligamentous complex following acute cervical spine trauma J Bone Joint Surg Am 2010;92:583-589 81 R onnen HR, de Korte PJ, Brink PR, van der Bijl HJ, Tonino AJ, Franke CL Acute whiplash injury: is there a role for MR imaging? a prospective study of 100 patients Radiology 1996;201:93-96 82 Ross MD, Cheeks JM Clinical decision making associated with an undetected odontoid fracture in an older individual referred to physical therapy for the treatment of neck pain J Orthop Sports Phys Ther 2008;38:418-424 http:// dx.doi.org/10.2519/jospt.2008.2687 83 Rostom S, Allali F, Bennani L, Abouqal R, Hajjaj-Hassouni N The prevalence of vertebral fractures and health-related quality of life in postmenopausal women Rheumatol Int 2011;http://dx.doi.org/10.1007/ s00296-010-1734-5 84 Sheehan NJ Magnetic resonance imaging for low back pain: indications and limitations Ann Rheum Dis 2010;69:7-11 http://dx.doi org/10.1136/ard.2009.110973 85 Shuster A, Franchetto A Surfer’s myelopathy-an unusual cause of acute spinal cord ischemia: a case report and review of the literature Emerg Radiol 2011;18:57-60 http://dx.doi.org/10.1007/ s10140-010-0913-8 86 Spitzer W, Skovron M, Salmi L, et al Scientific monograph of the Quebec Task Force on Whiplash-Associated Disorders: redefining "whiplash" and its management Spine (Phila Pa 1976) 1995;20:1S-73S 87 Stiell IG, Clement CM, McKnight RD, et al The Canadian C-spine rule versus the NEXUS lowrisk criteria in patients with trauma N Engl J Med 2003;349:2510-2518 http://dx.doi org/10.1056/NEJMoa031375 88 Stillerman CB, Chen TC, Couldwell WT, Zhang W, Weiss MH Experience in the surgical management of 82 symptomatic herniated thoracic discs and review of the literature J Neurosurg 1998;88:623-633 http://dx.doi.org/10.3171/ jns.1998.88.4.0623 89 Thompson TP, Pearce J, Chang G, Madamba J Surfer’s myelopathy Spine (Phila Pa 1976) 2004;29:E353-356 90 Tins BJ, Cassar-Pullicino VN Imaging of acute cervical spine injuries: review and outlook Clin Radiol 2004;59:865-880 http://dx.doi org/10.1016/j.crad.2004.06.019 91 Tsao H, Druitt TR, Schollum TM, Hodges PW Motor training of the lumbar paraspinal muscles induces immediate changes in motor coordination in patients with recurrent low back pain J Pain 2010;11:1120-1128 http://dx.doi org/10.1016/j.jpain.2010.02.004 92 Tsao H, Galea MP, Hodges PW Driving plasticity in the motor cortex in recurrent low back pain Eur J Pain 2010;14:832-839 http://dx.doi org/10.1016/j.ejpain.2010.01.001 93 Tsao H, Galea MP, Hodges PW Reorganization of the motor cortex is associated with postural control deficits in recurrent low back pain Brain 2008;131:2161-2171 http://dx.doi org/10.1093/brain/awn154 journal of orthopaedic & sports physical therapy | volume 41 | number 11 | november 2011 | 859 41-11 Elliott.indd 859 10/19/2011 5:39:19 PM Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on November 17, 2022 For personal use only No other uses without permission Copyright © 2011 Journal of Orthopaedic & Sports Physical Therapy® All rights reserved [ 94 T H, Tucker KJ, Hodges PW Changes in excitability of corticomotor inputs to the trunk muscles during experimentallyinduced acute low back pain Neuroscience 2011;181:127-133 http://dx.doi.org/10.1016/j neuroscience.2011.02.033 95 Uetani M, Hayashi K, Hashmi R, Nakahara N, Aso N, Ito N Traction injuries of the brachial plexus: signal intensity changes of the posterior cervical paraspinal muscles on MRI J Comput Assist Tomogr 1997;21:790-795 96 Vetti N, Krakenes J, Damsgaard E, Rorvik J, Gilhus NE, Espeland A Magnetic resonance imaging of the alar and transverse ligaments in acute whiplash-associated disorders and 2: a cross-sectional controlled study Spine (Phila Pa 1976) 2011;36:E434-440 http://dx.doi org/10.1097/BRS.0b013e3181da21a9 97 Vetti N, Krakenes J, Eide GE, Rorvik J, Gilhus NE, Espeland A Are MRI high-signal changes clinical commentary of alar and transverse ligaments in acute whiplash injury related to outcome? BMC Musculoskelet Disord 2010;11:260 http://dx.doi org/10.1186/1471-2474-11-260 98 Westbrook C, Kaut C MRI in Practice 2nd ed London, UK: Blackwell Sciences Ltd; 1998 99 Widder S, Doig C, Burrowes P, Larsen G, Hurlbert RJ, Kortbeek JB Prospective evaluation of computed tomographic scanning for the spinal clearance of obtunded trauma patients: preliminary results J Trauma 2004;56:1179-1184 100 Wood KB, Blair JM, Aepple DM, et al The natural history of asymptomatic thoracic disc herniations Spine (Phila Pa 1976) 1997;22:525529; discussion 529-530 101 Wood KB, Garvey TA, Gundry C, Heithoff KB Magnetic resonance imaging of the thoracic spine Evaluation of asymptomatic individuals J Bone Joint Surg Am 1995;77:1631-1638 102 Wood PB, Ledbetter CR, Glabus MF, Broadwell ] LK, Patterson JC, 2nd Hippocampal metabolite abnormalities in fibromyalgia: correlation with clinical features J Pain 2009;10:47-52 http:// dx.doi.org/10.1016/j.jpain.2008.07.003 103 Xiangshui M, Xiangjun C, Xiaoming Z, et al T magnetic resonance diffusion tensor imaging and fibre tracking in cervical myelopathy Clin Radiol 2010;65:465-473 http://dx.doi org/10.1016/j.crad.2010.01.019 04 Yanagisawa O, Shimao D, Maruyama K, Nielsen M Evaluation of exercised or cooled skeletal muscle on the basis of diffusion-weighted magnetic resonance imaging Eur J Appl Physiol 2009;105:723-729 http://dx.doi.org/10.1007/ s00421-008-0954-9 @ MORE INFORMATION WWW.JOSPT.ORG EARN CEUs With JOSPT’s Read for Credit Program JOSPT’s Read for Credit (RFC) program invites Journal readers to study and analyze selected JOSPT articles and successfully complete online quizzes about them for continuing education credit To participate in the program: Go to www.jospt.org and click on “Read for Credit” in the left-hand navigation column that runs throughout the site or on the link in the “Read for Credit” box in the right-hand column of the home page Choose an article to study and when ready, click “Take Exam” for that article Login and pay 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with spinal pain: with a focus on whiplash injury The Spine Journal 18:8, 1489-1497 [Crossref] 11 Rebecca J Crawford, Thomas Volken, Stephanie Valentin, Markus Melloh, James M Elliott 2016 Rate of lumbar paravertebral muscle fat infiltration versus spinal degeneration in asymptomatic populations: an age-aggregated crosssectional simulation study Scoliosis and Spinal Disorders 11:1 [Crossref] 12 Anette Karlsson, Olof Dahlqvist Leinhard, Ulrika Åslund, Janne West, Thobias Romu, Örjan Smedby, Peter Zsigmond, Anneli Peolsson 2016 An Investigation of Fat Infiltration of the Multifidus Muscle in Patients With Severe Neck Symptoms Associated With Chronic Whiplash-Associated Disorder Journal of Orthopaedic & Sports Physical Therapy 46:10, 886-893 [Abstract] [Full Text] [PDF] [PDF Plus] 13 Wang Mi Liu, Rong Xing, Chong Bian, Yun Liang, Libo Jiang, Chen Qian, Jian Dong 2016 Predictive value of pedicle involvement with MRI in spine metastases Oncotarget 7:38, 62697-62705 [Crossref] 14 J Mota Martínez, F Facal de Castro, R Mirón Mombiela 2016 Errores diagnósticos en la columna Radiología 58, 2-12 [Crossref] 15 R.J Crawford, L Filli, J.M Elliott, D Nanz, M.A Fischer, M Marcon, E.J Ulbrich 2016 Age- and Level-Dependence of Fatty Infiltration in Lumbar Paravertebral Muscles of Healthy Volunteers American Journal of Neuroradiology 37:4, 742-748 [Crossref] 16 Jessie J Mathers 2012 Differential diagnosis of a patient referred to physical therapy with neck pain: a case study of a patient with an atypical presentation of angina Journal of Manual & Manipulative Therapy 20:4, 214-218 [Crossref] 17 &NA; 2012 Bibliography Current World Literature Current Orthopaedic Practice 23:3, i-xi [Crossref] 18 James M Elliott 2011 Magnetic Resonance Imaging: Generating a New Pulse in the Physical Therapy Profession Journal of Orthopaedic & Sports Physical Therapy 41:11, 803-805 [Abstract] [Full Text] [PDF] [PDF Plus]