Genitourinary tract imaging - part 8 ppsx

Most experts agree that a complete urologic evaluation should include imaging of the upper urinary tract and cytoscopic examination of the urinary bladder. The role of urine cytology is controversial, as a negative cytology can never completely exclude the presence of a bladder tumor [12]. The goal of imaging is to detect neoplasms, including renal cell carcinoma (RCC), and the less prevalent transitional cell carcinoma (TCC), of the renal pelvis and ureters, urinary tract calculi, renal cystic disease, and obstructive lesions [11]. This article discusses the current status of imaging of patients suspected of having urologic causes of hematuria. The imaging of posttraumatic hematuria, of patients with UTI, and patients with glomer- ular causes of hematuria is beyond the scope of this review. The role of all modalities, including plain radiography, intravenous urography or excretory urography, retrograde pyelography, ultrasonography, multidetector computed tomography (MDCT), including MDCT urography (MDCTU) and mag- netic resonance (MR) urography, is discussed. In recent years, MDCTU has undergone significant development and has been the subject of research and investigation as a new technique for evaluation of patients with urinary tract pathology [13,14]. Evidence is accumulating, which suggests that this technique is now ready to play a pivotal role in imaging of patients presenting with hematuria. This article highlights the current status of MDCTU in imaging of patients with hematuria, and discusses various—often controversial—issues, such as opti- mal protocol design, accuracy of the technique in imaging of the urothelium, and the significant issue of radiation dose associated with MDCTU. Common urologic causes of hematuria Urinary tract calculi Urolithiasis is associated with idiopathic hypercalciuria, secondary hypercalciuria, and hyperuricosu- ria [15]. Stones are most commonly composed of calcium oxalate and phosphate (34%), calcium oxalate (33%), calcium phosphate (6%), mixed struvite and apatite (15%), uric acid (8%), and cys- tine (3%) [3]. Nephrocalcinosis is characterized by the formation of calculi within renal tubules and interstitium, leading to impaired renal function [16]. Nephrocalcinosis is associated with medullary sponge kidney, renal tubular acidosis, and hyper- parathyroidism, and may present with hematuria [16,17]. Urinary tract calculi frequently present with ureteric colic caused by obstruction of the urinary collecting system. With regard to the associa- tion of urinary tract calculi with development of microscopic hematuria, a recent study by Edwards and colleagues [6] showed a prevalence of urinary tract calculi of 7.8% in adult patients with microscopic hematuria and 8.8% in patients with macro- scopic hematuria. Malignancy The most common malignant conditions associated with hematuria in adults are renal cell carcinoma, transitional cell carcinoma, prostate carcinoma, and less commonly, squamous cell carcinoma, which can result from chronic inflamma- tory conditions [18–20]. RCC is the most common malignant neoplasm of the kidney, representing up to 90% of renal neoplasms and up to 3% of all neoplasms [18,21]. RCC is more common in men than women, has a peak incidence at 60 to 70 years of age, and is associated with smoking, obesity, and antihypertensive therapy [22]. In recent years, the triad of flank pain, hematuria, and a palpable mass is less frequently the mode of presentation for RCC, because over 50% of lesions are identified by cross-sectional imaging, either incidentally or when performed for vague and apparently unrelated symptoms. This is not sur- prising, as systemic symptoms, such as anorexia and weight loss, are commonlyassociated withRCC [23]. Urothelial tumors account for 10% of upper urinary tract neoplasms [24]. Although urothelial malignancies are most likely to occur in the bladder, the ureters have been reported to be involved in 2%, and the renal pelvis (extrarenal pelvis in preference to infundibulocalyceal regions) in 5% of cases [19,25]. The multifocal and bilateral nature of TCC makes this a challenging condition for the radiologist [23]. Synchronous tumors occur in up to 2% of renal and 9% of ureteric lesions, with metachronous lesions typically occurring within the bladder in up to 50% of cases with upper ureteric tumors on presentation [26,27]. Therefore, imaging is required for primary diagnosis of TCC but is also very commonly used for detection of synchronous and metachronous lesions [23]. Bladder neoplasia is the fifth most common malignancy in Europe and the fourth most common cancer in the United States [28]. TCC of the bladder occurs more commonly in men than women, is associated with smoking (fourfold greater than in nonsmokers), exposure to chemicals such as ben- zene and 2-naphtylamine, and structural abnormal- ities (horseshoe kidney) [29,30]. Squamous cell carcinoma and adenocarcinoma are significantly less common in the bladder than TCC [31]. Greater than 70% of bladder cancers are superficial and 25% invade muscle at the time of diagnosis [32]. Bladder cancer most frequently presents with hematuria but can be associated with more nonspe- cific signs, such as urinary frequency and urgency, dysuria, and suprapubic pain [23]. O’Connor et al 114 . 7 .8% in adult patients with microscopic hematuria and 8. 8% in patients with macro- scopic hematuria. Malignancy The most common malignant conditions associated with hematuria in adults are. the associa- tion of urinary tract calculi with development of microscopic hematuria, a recent study by Edwards and colleagues [6] showed a prevalence of urinary tract calculi of 7 .8% in adult. current status of imaging of patients suspected of having urologic causes of hematuria. The imaging of posttraumatic hematuria, of patients with UTI, and patients with glomer- ular causes of