The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Diffusion-Weighted MR Imaging in differential diagnosis Grade-2 lesion or Grade-3 lesi
Trang 1INTRODUCTION
Nasopharyngeal carcinnoma (NPC) is a malignant tumor originating from epithelial cells in the nasopharynx Since the primary treatment method for this disease is radiation therapy, obtaining postoperative specimens for disease staging is not feasible Therefore, experts rely entirely on imaging techniques, particularly magnetic resonance imaging (MRI), for disease staging Due to the anatomical complexity and histological characteristics of the nasopharyngeal area, accurately determining the extent of invasion poses significant challenges
Currently, conventional MRI has proven its crucial role in detecting and assessing nasopharyngeal tumors and their local invasions by providing detailed images of soft tissue structures and invasion levels However, in certain cases, conventional MRI encounters difficulties in distinguishing the nature of tumors Recently, diffusion-weighted imaging (DWI), an advanced MRI technique, has emerged as a non-invasive method providing critical biological insights into tumors, aiding in distinguishing cancer from inflammation or edema
Globally, several studies have applied DWI MRI to measure ADC (Apparent Diffusion Coefficient) values in nasopharyngeal tumors for tumor classification However, these studies have not delved deeply into evaluating the histological grade of malignancy Assessing the histological malignancy grade of NPC based on ADC values is essential to enhance diagnostic accuracy and improve treatment quality for patients
In Vietnam, several studies have explored the role of techniques such
as computed tomography (CT), positron emission tomography-computed tomography (PET-CT), and conventional MRI in diagnosing nasopharyngeal cancer However, in the field of MRI, no in-depth studies have specifically examined the value of both conventional MRI and DWI
in assessing tumor malignancy levels and lymph node metastasis in NPC Therefore, we study the project: "Diagnosis of Nasopharyngeal Carcinoma Staging by Magnetic Resonance Imaging" with the following objectives:
1 Describing the imaging characteristics of nasopharyngeal carcinoma on magnetic resonance imaging
2 Evaluating the TNM stage of nasopharyngeal carcinoma on magnetic resonance imaging
Trang 21 Novel contributions of the thesis:
- Diffusion-Weighted MR Imaging can predict the histological malignancy of NPC lesions The mean ADC value of the lesion is 0.823±0.124 x10-3 mm2/s, the minimum ADC value is 0.652 x10-3 mm2/s, and the maximum ADC is 0.1248 x10-3 mm2/s The mean ADC value of the Grade-2 lesion is 0.893 ± 0.127 x10-3 mm2/s, and the mean ADC value of the Grade-3 lesion is 0.750 ± 0.066 x10-3 mm2/s The threshold of the ADC value that distinguishes between Grade-2 lesion and Grade-3 lesion is 0.792 x10-3 mm2/s The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Diffusion-Weighted MR Imaging in differential diagnosis Grade-2 lesion or Grade-3 lesion are 86.2%, 78.6%, 80.6%, 84.6%, and 82.5%, respectively
- Diffusion-Weighted MR Imaging can predict the benign or malignant criteria of cervical ganglia in NPC The mean ADC value of the benign cervical lymph nodes is 1.322 ± 0.231 x10-3 mm2/s, and the mean ADC value of the cervical lymph nodes is 0.870 ± 0.187 x10-3 mm2/s The threshold of ADC value that distinguishes benign and malignant cervical lymph nodes is 0.924 x10-3 mm2/s The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Diffusion-Weighted MR Imaging in the differential diagnosis of benign or malignant cervical lymph nodes are 92.6%, 81.4%, 69.4 %, 96%, and 84.9%, respectively
2 Thesis layout:
The thesis consists of 130 pages Apart from the introduction (2 pages), the conclusion (2 pages) and the recommendations (1 page), it also has four chapters include: Chapter 1: Overview 40 pages; Chapter 2: Materials and methods 16 pages; Chapter 3: Results 34 pages; Chapter 4: Discussion 35 pages The thesis consists of 41 tables, 03 charts, 19 pictures, and 133 references
Chapter 1 OVERVIEW 1.1 Literature review in Vietnam
Nguyen Van Huong et al (2015) studied 3.0T MRI with pulse sequences T1W, T2W, STIR, and CE T1W from patients with tumors in the oral cavity and pharynx upper the hyoid bone, found that about 80% of tumors were hypointense on T1W, 76% were hyperintense on T2W, 81% were hyperintense on STIR, 79% of tumors have moderate and high enhancement Approximately 79% of tumors have irregular margins of unclear boundaries Malignant lymphadenopathy on MRI accounts for
Trang 3about 68% The ability to diagnose tumor malignancy on T1W image has
a sensitivity of 86%, a specificity of 71%, and a positive predictive value
of 95%; on T2W images, there was a sensitivity of 84%, a specificity of 85%, a positive predictive value of 97%; on the STIR image has a sensitivity of 90%, a specificity of 85%, a positive predictive value of 97%,
a negative predictive value of 54% The tumor had a moderate enhancement pattern and had a sensitivity of 86%, a specificity of 71%, and a positive predictive value of 95% MRI can diagnose cervical lymph node malignancy with a sensitivity of 69%, specificity of 42%, and positive predictive value of 90%
Tran Xuan Bach and Bui Van Giang (2021) evaluated the perineural and vascular invasion of 62 nasopharyngeal carcinoma lesions on MRI 1.5 Tesla Their studynd reported that 18 patients (29%) showed MRI evidence of perineural invasion, while 14 patients (22.6%) exhibited perivascular invasion (in which the rate of invasion around the petrous carotid artery accounted for the highest rate of 16.1%) Therefore, the authors concluded that MRI images of nasopharyngeal tumors invading perineurally and vascularly play an important role in staging, helping clinicians in devising treatment plans
1.2 Literature review in the world
Vineet Vijay Gorolay et al (2022) retrospectively studied nine articles
on the value of MRI in evaluating NPC, analyzed 1736 cases with 337 patients diagnosed with NPC, and concluded that MRI has a sensitivity of 98.1 % (95%CI: 95.2-99.3%) and 91.7% specificity (95%CI: 88.3-94.2%)
in the diagnosis of NPC
King A.D et al (2006) examined MRI 533 cases and concluded that MRI has 100% sensitivity, 95% specificity, 100% negative predictive value, 43% positive predictive value and 95% accuracy in diagnosing NPC MRI has the potential to screen healthy patients who do not require endoscopic guided biopsy and direct the site of biopsy in small cancers that may be missed by endoscopy
In Devin Fong et al study (2010), one hundred patients with newly diagnosed NPC, head and neck lymphoma, or squamous cell carcinoma (SCC) underwent echo-planar DWI Mean ADC of NPC, lymphoma and SCC were 0.98 ± 0.161, 0.75 ± 0.190, 1.14 ± 0.196 x10-3 mm2/s) respectively which were significantly different (p < 0.001–0.003) Optimized ADC thresholds of 0.779, 0.768 and 1.07 x10-3 mm2/s) achieved maximal discriminatory accuracies of 100%, 93% and 70% for SCC/lymphoma, NPC/lymphoma, and SCC/NPC respectively DWI may
Trang 4still be useful clinically to distinguish NPC from nasopharyngeal lymphoma in populations with endemic NPC due to the relative rarity of nasopharyngeal SCC
Forty-two patients with early-stage NPC, sixteen with lymphoma, eleven with tuberculosis, and twenty-six with nasopharyngitis were included in the retrospective study of Dechun Zheng et al (2012) All patients underwent nasopharynx and skull base region MR Imaging and nasopharynx-fiberscope biopsy and were finally diagnosed with histopathologically proven (n = 86) and clinical follow-up (n = 9) Mean ADC values of malignant nasopharyngeal lesions (early stage NPC and lymphoma) and benign nasopharyngeal lesions (tuberculosis and nasopharyngitis) were (0.708 ± 0.158) and (0.913 ± 0.168) x 10-3 mm2/s, respectively (t = 6.05, P < 0.01) Mean ADC values of nasopharyngeal lesions of early-stage NPC, lymphoma, tuberculosis, and nasopharyngitis were (0.753 ± 0.135), (0.590 ± 0.156), (0.855 ± 0.137), and (0.935 ± 0.179)
× x 10-3 mm2/s, respectively (F = 18.89, P < 0.01), and post multiple comparisons showed that they were all statistical significance on 0.05 level between NPC, lymphoma, tuberculosis, and nasopharyngitis except subgroup tuberculosis and nasopharyngitis (p = 0.55); An ADC value lower than or equal to 0.828 x 10-3 mm2/s was used as the threshold for nasopharyngeal malignancy, with a sensitivity 82.8% and specificity of 70.3% When the same ADC value ≤ 0.828 x 10-3 mm2/s was used as a threshold to differentiate early-stage NPC from nasopharyngitis, sensitivity and specificity were 78.6% and 69.2%, respectively When an ADC value ≤ 0.681 x 10-3 mm2/s was used as a threshold to differentiate lymphoma from early-stage NPC, sensitivity and specificity were 81.3% and 71.4%, respectively The author concluded that DWI has a potential value in determining nasopharyngeal diseases
Ann D King et al (2000) studied the MR images of 150 patients with newly diagnosed NPC, which were reviewed retrospectively and gave the results: Retropharyngeal nodes (RN) were more frequently involved than nonretropharyngeal nodes (NRNs) (94% vs 76% in 115 patients with nodal metastases) NRN involvement without RN was seen in only 7 of 115 patients (6%) The involvement of RNs at the level of the oropharynx (82%) was as common as at the nasopharynx (83%) level Internal jugular nodes were the most frequently involved NRN nodes (72%) Spinal accessory nodal involvement was also common (57%) but seldom in isolation (8%) Submandibular (3%) and parotid (2%) nodal metastases were uncommon and were always associated with advanced nodal metastases in the ipsilateral
Trang 5RNs, internal jugular, and spinal accessory regions The author concluded that retropharyngeal nodes were the first echelons of nodal metastases Direct lymphatic spread to the neck without the involvement of the RNs was uncommon RNs metastases at the level of the oropharynx were more common than previously suspected, and this should influence radiotherapy planning NRNs outside the internal jugular and spinal accessory chains were rare and only occur when the tumor has blocked the usual lymphatic spread routes
Forty-three patients with malignant lymphadenopathy underwent 1.5-T diffusion-weighted MR imaging in the study of Ann D King et al (2007) Mean ADC values for lymphoma (n = 8), NPC (n = 17), and SCC (n = 18) were (0.664 +/- 0.071) x 10-3 mm2/s, (0.802 +/- 0.128) x 10-3 mm2/s, and (1.057 +/- 0.169) x 10-3 mm2/s, respectively, with significant differences between SCC and lymphoma or NPC (p < 0.001) and between NPC and lymphoma (P = 04) To optimize sensitivity and specificity with equal weighting, ADC threshold values for distinguishing between SCC and NPC, between SCC and lymphoma, and between NPC and lymphoma were 0.894
x 10-3 mm2/s, 0.824 x 10-3 mm2/s, and 0.694 x 10-3 mm2/s, respectively To produce a 100% specificity while sensitivity was maximized, the following ADC threshold values were obtained for prediction of differentiation between malignancies: (a) SCC versus lymphoma, greater than 0.824 x 10-
3 mm2/s (sensitivity, 94%), and lymphoma versus SCC, less than 0.767 x 10
-3 mm2/s (sensitivity 88%); (b) NPC versus SCC, less than 0.764 x 10-3
mm2/s (sensitivity, 47%), and SCC versus NPC, greater than 1.093 x 10-3
mm2/s (sensitivity, 39%); (c) NPC versus lymphoma, greater than 0.788 x
10-3 mm2/s (sensitivity, 53%), and lymphoma versus NPC, no suitable threshold value From that, the author concluded that Diffusion-weighted
MR imaging shows significant differences among malignant nodes of SCC, lymphoma, and NPC ADC threshold values can help distinguish SCC from lymphoma
In Ann D King et al study (2011), 246 patients suspected of having NPC underwent MR imaging, endoscopy, and endoscopic biopsy NPC was present in 77 (31%) of 246 patients and absent in 169 (69%) The combined sensitivity, specificity, and accuracy, respectively, were 100%, 93%, and 95% for MR imaging, 90%, 93%, and 92% for endoscopy, and 95%, 100%, and 98% for endoscopic biopsy The benign disease was mistaken for NPC in 12 (7%) of 169 patients at MR imaging and in 11 (6%) patients at endoscopy The sensitivity of MR imaging was
Trang 6significantly higher than that of endoscopy (P = 006) and was similar to that of endoscopic biopsy (p = 120) The specificity of MR imaging was similar to that of endoscopy (p =0 120) and was significantly lower than that of endoscopic biopsy (p<0.001) The author concluded that MR imaging was an accurate test for diagnosing NPC MR imaging depicts subclinical cancers missed at endoscopy and endoscopic biopsy and helps identify the majority of patients who do not have NPC and therefore do not need to undergo invasive sampling biopsies
Fifty-three patients affected with NPC were studied with MRI and CT
in the Patrizia Olmi et al study (1995) The author concluded: Staging: CT and MRI can provide essential information in the staging of NPC MRI offers the most detailed imaging of soft tissue invasion outside the nasopharynx and of retropharyngeal node involvement Nonetheless, its limitations in evaluating bone details suggest that CT should always be performed when the status of the skull base was uncertain on MRI Magnetic resonance may be the modality of choice because it seems to solve, more often than CT, the problems of differentiation between post-radiation changes and recurring tumor, apart from those cases showing subtle bone erosions on initial CT scan
Jun Han et al (2012) collected MRI data from 101 NPC patients with skull base invasion to investigate the incidence and anatomic sites of invasion of NPC in the skull base Of the 101 NPC patients, 84 had direct invasion at the skull base (83.2%), and 17 had skull base metastasis (16.8%) Affected sites with direct invasion in the skull base included the sphenoid sinus and sella base, cavernous sinus, internal carotid canal, and clivus blumenbachii Skull base metastasis sites included the internal carotid canal and jugular foramen area Because of early lymphatic metastasis of NPC to the skull base, MRI examination can be helpful in increasing the accuracy of diagnostic imaging for skull base invasion of NPC and selecting appropriate target sites, radiotherapy techniques, and operative approaches
Chapter 2 MATERIALS AND METHODS
2.1 Research subjects
2.1.1 Inclusion criteria
Patients admitted to the hospital suspected of having NPC underwent 1.5T
Trang 7MR imaging, endoscopy, and endoscopic biopsy and treatment plan
2.1.2 Exclusion criteria
- Magnetic resonance imaging was unsatisfactory due to the lack of
sequences needed in the study or taken after treatment
- Treated nasopharyngeal tumors or cervical lymph nodes (surgery, radiation, chemotherapy, etc.)
2.2 Methodology
- Methodology: cross-sectional study, prospective
- Research site: Ho Chi Minh City Oncology Hospital
- Research time: from May 2016 to October 2021
2.2.1 Estimated patient number
Estimated sampling was 78 patients
2.2.2 Definition of research variables
- General characteristics of research subjects: age, gender, the clinical syndromes of NPC, endoscopy result, histopathology result
- MRI characteristics of NPC: site, morphologic feature, size, tumor invasion, T1W, T2W, T2 FS, CE T1, DWI
- MRI characteristics of cervical lymph nodes: site, morphologic feature, size, T1W, T2W, T2 FS, CE T1, DWI; malignant lymph node, benign lymph node
- Staging of NPC according to the 8th edition of the The American Joint Committee on Cancer’s TNM staging system
- The correlation between dependent and independent variables was tested using hypothesis testing, with statistically significant differences at
p <0.05, which was not statistically significant with p> 0.05
- ROC curve analysis helps to investigate the value of diagnostic test The threshold of the best diagnostic test value applied according to the Youden index
Trang 8Chapter 3 RESULTS
The study was conducted from May 2016 to October 2021 on 125 patients, divided into two groups: Group 1 consisted of 98 patients who visited the hospital with suspected nasopharyngeal carcinoma (NPC) symptoms These patients underwent nasopharyngeal endoscopy and biopsy While awaiting biopsy results, they underwent MRI scans of the head and neck region This was the primary group in which all study variables were examined Group 2 consisted of 27 patients who presented with cervical lymph nodes during their head and neck examinations These patients underwent MRI, received treatment, and were diagnosed upon discharge with benign conditions This group was used to assess the quantitative ADC values of benign cervical lymph nodes
3.1 General features
3.1.1 Age and gender
The mean age was 49.85 ± 14.03 years old The youngest age was 20, and the oldest was 78 Patients over 40 years old with NPC accounted for 75.3% The prevalence was highest in the 51-60 age group (28.4%) The
male-to-female ratio was 1.6/1
3.1.2 Clinical and paraclinical characteristics
Of the four clinical syndromes in NPC, ganglion syndrome has the highest rate (63%), followed by nasal-sinus syndrome (50, 6%), ear syndrome (37%), and neurological syndrome (24.7%)
The first endoscopy detected 79/81 (97.5%) cases of nasopharyngeal carcinoma, and missed 2/81 (2.5%) cases
Eighty-one patients with nasopharyngeal carcinoma were all keratinizing squamous cell carcinomas
non-3.2 MR imaging characteristics of primary NPC
The most common NPC location was in the lateral wall (62 patients, 76.6%), mainly unilateral (55.6%)
There were 61 patients (75.3%) whose lesions were invasive tumors, accounting for the highest frequency Next was the localized tumor, which has not spread and invaded the organs around the nasopharynx at 22.2% Abnormal mucosal thickening has a very low rate of 2.5% Tumors ranged
in size from 7 to 52 mm in maximum diameter with a mean of 26,2 ± 11,9
mm
The frequencies of NPC lesions with hypointensity on T1W, hyperintensity on T2W, and hyperintensity on T2FS were 64.2%, 84%, and 88.9%, respectively All lesions (81 patients, 100%) were contrast-enhanced,
Trang 9in which the rate of high contrast enhancement lesions accounted for 86.4%, and heterogeneous enhancement accounted for 59.3%
The NPC lesions had a mean ADC value of 0.823 ± 0.124 x10-3 mm2/s, the minimum ADC value was 0.652 x10-3 mm2/s, and the maximum was 0.1248 x10-3 mm2/s
The mean ADC value of the Grade-2 lesion was 0.893 ± 0.127 x10-3
mm2/s, higher than the mean ADC value of the Grade-3 lesion 0.750 ± 0.066 x10-3 mm2/s The difference was statistically significant (p < 0.001) The threshold of the ADC value that distinguishes between the Grade-2 lesion and Grade-3 lesion was 0.792 x10-3 mm2/s The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MRI in differential diagnosis Grade-2 lesion or Grade-3 lesion were 86.2%, 78.6%,
The T-stage distribution of NPC was different The T1 stage disease was found to be highest in 33.3% of cases, followed by the T4 stage (32.1%), and the frequencies of patients in the T2 stage and T3 stage were the same (17.3%)
3.3.2 The correlation between the anatomical sites of tumor invasion
by NPC
Tumors invading the parapharyngeal space had the frequencies of invasion of the skull base at 70.4% and cranial invasion at 29.6% When the tumor invaded the parapharyngeal space, the risk of invasion of the skull base increased 4.3 times (p=0.003; 95%CI: 1.164-11,859), and the risk of cranial invasion increased 3.4 times (p=0.038; 95%CI: 1.031-11.010)
Tumors invading the prevertebral muscles had the frequency of invasion of the skull base at 72% When the tumor invaded the prevertebral muscles, the risk of invasion of the skull base increased 4.6 times (p=0.003; 95%CI: 1.652-12,965)
Tumors invading the sphenoid sinus had the frequency of invasion of the cranium at 57.9% When the tumor invaded the sphenoid sinus, the risk
Trang 10of invasion of the cranium increased 27 times (p<0.001; 95%CI: 118.175)
6.188-3.3.3 Value of routine MR Imaging in the evaluation of NPC
The overall percentage accuracy of five individual sequences of the NPC was as follows: 79% for axial T1W, 85.2% for FS axial T2W, 77.8% for corronal T1W, and 86.4% for CE FS corronal T1, and 92.6% for CE
FS axial T1
The overall sensitivity for each stage of the NPC with five different sequences was as follows: 100% for T1, 72.8% for T2, 77.1% for T3, and 77.7% for T4
3.3.4 Evaluating MRI characteristics of middle ear effusion in NPC
Among 81 patients with NPC, 25 (30.9%) had middle ear effusion detected on MRI
There was a statistically significant difference in the frequency of middle ear effusion in 2 groups of NPC patients with and without clinical ear syndrome (p<0.001) NPC patients with ear syndrome had a 20 times higher risk of middle ear effusion than patients without ear syndrome (p<0.001; 95% confidence interval; 2.278-175,557)
Among 62 patients with NPC at the lateral wall, 20 (32.3%) had middle ear fluid effusion There was a relationship between middle ear effusion and primary tumor sites (p=0.048)
3.4 MR imaging characteristics of cervical lymph nodes metastasised from NPC
Metastatic non-retropharyngeal nodes (NRN) had a mean shortest axial diameter of 15.58 ± 5.7mm; the minimum shortest axial diameter was
10 mm, and the minimum shortest axial diameter was 38 mm Metastatic retropharyngeal nodes had a mean shortest axial diameter of 10.89 ± 4.1 mm; the minimum shortest axial diameter was 5 mm, and the minimum shortest axial diameter was 22 mm
Enlarged lymph nodes accounted for the highest rate (91.9%) Necrotic and extracapsular spread lymph nodes had low rates of 4.1% and 6.8%, respectively Cluster lymph nodes were the least common (1.4%)
The mean ADC value of the benign cervical lymph nodes was 1.322
± 0.231 x10-3 mm2/s, higher than the mean ADC value of the cervical lymph nodes, 0.870 ± 0.187 x10-3 mm2/s The difference was statistically significant (p < 0.001)
The threshold of ADC value that distinguishes benign and malignant cervical lymph nodes was 0.924 x10-3 mm2/s The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of
Trang 11magnetic resonance in the differential diagnosis of benign or malignant cervical lymph nodes were 92.6%, 81.4%, 69.4 %, 96%, and 84.9%, respectively
3.5 Evaluating the N stage (cervical lymph node) of NPC on MR imaging 3.5.1 Incedence and distribution of metastatic cervical lymph nodes
Among 81 NPC patients, 74 (91.4%) cervical lymph node metastasis was present Patients with the N2 stage accounted for the highest incidence (42%), followed by the N1 stage (39.5%) The lowest was the group of patients with the N3 stage (9.9%)
Among 74 patients with metastatic neck lymph nodes, there were no Level VI and Level VII lymph nodes Level II lymph nodes accounted for the highest frequency (82.7%), followed by retropharyngeal lymph nodes (RN) (47%), Level III lymph nodes (45.7%), Level I lymph nodes (34.6%), and Level V lymph nodes (19.8%) Level IV lymph nodes
accounted for the lowest frequency (11.1%)
In each group of metastatic cervical lymph nodes, there was a difference in the frequency of unilateral and bilateral lymph nodes The frequency of bilateral lymph nodes was higher than that of unilateral lymph nodes, presented in patients with Level I, II, and III lymph nodes The frequency of unilateral lymph nodes was higher than that of bilateral lymph nodes, presented in patients with Level IV, Level V, and retropharyngeal lymph nodes
The incidence of metastatic RNs (55 nodes) shows an orderly decrease
from the C1 to C3 level
3.5.2 Correlation between metastatic cervical lymph nodes and the extent of the primary tumor
Eighty-one NPC patients distributed in each stage group from T1 to T4 had cervical lymph node metastasis with different and high frequency, over 85% Patients in the T4 stage had the highest frequency of cervical lymph node metastasis (96.2%); in the last stages, the frequency of cervical lymph node metastasis was over 85% There was no statistically significant difference (p=0.666) in cervical lymph node metastasis frequencies between the T1-T4 stages The frequencies of metastatic Level
II lymph nodes in T1-T4 stages were over 85%; the highest was in the T4 stage (96%)
NPC patients, with or without extra nasopharyngeal invasion, had a relatively high frequency of cervical lymph node metastasis, over 90%
Trang 12There was a correlation between invasive NPC lesions and RN metastasis (p=0.001) When the tumor extended the surrounding area, the
risk of RN metastasis increased 14.2 times (95% CI: 2.420-82.917)
There was a correlation between NPC lesions extending nasal cavity and Level II lymph node metastasis (p=0.010; 95% CI: 0.009-0.814) When the lesion extended the oropharynx, nasal cavity, parapharyngeal space, prevertebral muscles, skull base, cranium, sphenoid sinus, and orbit, the frequency of metastasis to RN was over 90%
There was a correlation between NPC lesions extending parapharyngeal space, skull space, sphenoid sinus, and RN metastasis When the tumor extended the parapharyngeal space, the risk of RN metastasis increased by 74.2% (p=0.030; 95%CI: 0.603-0.913) When the tumor extended the skull base, the risk of RN metastasis increased 10.73 times (p=0,013; khoảng tin cậy 95%: 1,197-96,283) When the tumor extended the sphenoid sinus, the risk of RN metastasis increased by 74.2% (p=0.030; 95%CI: 0.603-0.913)
The frequencies of metastatic RN increased gradually from the T1 stage to the T4 stage There was a difference in the frequencies of metastatic RN in the T1-T4 stages (p=0.030)
The frequencies of metastatic RN increased gradually from the N1 stage to the N3 stage
Metastatic RN was not seen in stage I The frequency of metastatic
RN increased gradually in stage II (54.5%), stage III (82.4%), and stage
IV (100%) There was a correlation between the frequency of RN and stages II, III, and IV (p=0.007) As the stage was leveled up, the frequency
of metastatic RN was also leveled up
3.6 Evaluating the M stage (metastasis) of NPC on MR imaging
In this study, we did not use whole-body MRI to screen for distant metastases Therefore, we initially assessed the distant metastatic stage of NPC on MRI as Mx
All 81 patients with nasopharyngeal cancer obtained SPECT, chest ray, and an abdominal ultrasound to screen and evaluate distant metastases All patients had no imaging findings suggestive of distant metastases From there, we assessed the M stage of 81 nasopharyngeal cancer patients as M0