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  1. 1. 28th Annual In-Training Examination for Diagnostic Radiology Residents Rationales Sponsored by: Commission on Education Committee on Residency Training in Diagnostic Radiology February 3, 2005 The American College of Radiology www.acr.org
  2. 2. Section VII – Genitourinary Tract Radiology Figure 1A Figure 1B American College of Radiology
  3. 3. Section VII – Genitourinary Tract Radiology 170. You are shown a contrast enhanced CT (Figures 1A and 1B) of a 65-year-old woman with diabetes and intermittent fevers. What is the MOST likely diagnosis? A. Acute pyelonephritis B. Xanthogranulomatous pyelonephritis C. Acute left ureteral obstruction D. Multilocular cystic nephroma Question #170 Findings: Images demonstrate left cortical thinning, dilated collecting system, infiltration of the fat adjacent to the left kidney, and calcifications in the left renal collecting system. Rationales: A. Incorrect. In early acute pyelonephritis, the kidney may actually appear within normal limits on CT, particularly on noncontrast scanning, but in more advanced cases, after intravenous contrast may demonstrate striated nephrogram or focal wedge-like areas of abnormally decreased enhancement. Although the infiltration of fat seen around the kidney in this case could be seen with acute pyelonephritis, the obstructing stone, cortical thinning, and dilated, fluid-filled collecting system suggests a more chronically obstructed, infected system. B. Correct. Xanthogranulomatous pyelonephritis is a chronic suppurative granulomatous infection in the setting of chronic obstruction. Common organisms are Proteus mirabilis and E Coli. Histologically there is diffuse infiltration by plasma cells and lipid-laden macrophages. Symptoms are generally of long duration, and the affected kidney is nonfunctioning. The kidney is diffusely enlarged, but maintains its reniform shape, with one or more relatively large calculi typically seen. The renal pelvis is typically poorly defined or normal in size, as in this case. C. Incorrect. While acute obstruction could result in hydronephrosis and perinephric stranding, it would not account for the cortical thinning seen here, and with acute obstruction, one would expect to see dilatation of the renal pelvis. D. Incorrect. Multilocular cystic nephroma is an uncommon renal neoplasm containing many cysts of varying sizes, surrounded by a thick fibrous capsule. Calcifications may rarely be seen, but are usually only in the cyst walls or intervening stroma. It would not account for the significant infiltration of the adjacent perinephric fat seen in this case. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Diagnostic In-Training Exam 2005
  4. 4. Section VII – Genitourinary Tract Radiology Figure 2A Figure 2B American College of Radiology
  5. 5. Section VII – Genitourinary Tract Radiology 171. You are shown an axial image (Figure 2A) and a coronal reconstructed image (Figure 2B) from an abdominal CT of a 25-year-old African American man with sickle cell trait, flank pain and hematuria. What is the MOST likely diagnosis? A. Non-Hodgkin’s lymphoma B. Angiomyolipoma C. Renal medullary carcinoma D. Transitional cell carcinoma Question #171 Findings: A large infiltrative mass is present in the right kidney with extension of mass into the renal pelvic fat, the right renal vein and IVC. There is also retroperitoneal lymphadenopathy and splenomegaly. Rationales: A. Incorrect. Non-Hodgkin’s lymphoma can involve the kidney but is seen on presentation in only 5.8% of cases. Although it can involve the kidney as a single mass, renal lymphoma most commonly presents as multiple lymphomatous masses. Additionally, renal vein and IVC invasion would be distinctly unusual for lymphoma. B. Incorrect. Angiomyolipoma is a benign tumor of the kidney that is characterized by regions of macroscopic fat (seen in 95% of cases). No areas of fat density are seen in the images provided with this case. Additionally, renal vein and IVC invasion and lymphadenopathy would not be a characteristic of this benign tumor. C. Correct. Renal medullary carcinoma is an unusual tumor that almost always occurs in young patients with sickle cell trait. No cases have been reported in patients with sickle cell disease. The tumor arises from the calyceal epithelium and grows in an infiltrative pattern. It is a very aggressive tumor with early metastases to lymph nodes and vascular invasion. D. Incorrect. Transitional cell carcinoma can fill the renal pelvis and diffusely infiltrate the kidney as in this case. However, transitional cell carcinomas typically affect older individuals and would be rare to affect someone of this age. Also, transitional cell carcinomas would not demonstrate vascular invasion as in this case. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Lowe LH, Isuani BH, Heller RM, et al. Pediatric renal masses: Wilms tumor and beyond. Radiographics. 2000;20:1585-1603. Diagnostic In-Training Exam 2005
  6. 6. Section VII – Genitourinary Tract Radiology Figure 3 172. You are shown an abdominal CT image of a 39-year-old woman (Figure 3). What is the MOST likely diagnosis? A. Adenoma B. Lymphangioma C. Metastasis D. Myelolipoma American College of Radiology
  7. 7. Section VII – Genitourinary Tract Radiology Question #172 Findings: Left adrenal mass containing gross fat and a small amount of coarse calcium. Rationales: A. Incorrect. Adenomas rarely calcify. Although 80% do contain fat, it is intracytoplasmic, and is usually not grossly fatty as in this case. B. Incorrect.Lymphangioma should be water density and not fatty. C. Incorrect. The adrenal glands are a common site of metastatic disease, but adrenal metastases are typically soft tissue density. Larger metastases to the adrenals may have central necrosis or areas of hemorrhage, but would not have a fatty component. D. Correct. Myelolipomas are uncommon benign tumors of the adrenal gland comprised of mature adipose cells and hematopoietic tissue. They are functionally inactive and usually are detected as incidental findings. A grossly fatty adrenal mass is virtually diagnostic of a myelolipoma. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Diagnostic In-Training Exam 2005
  8. 8. Section VII – Genitourinary Tract Radiology Figure 4 173. You are shown an image from a hysterosalpingogram (Figure 4) of a 34-year-old woman with infertility. Which one of the following is the MOST likely diagnosis? A. Salpingitis isthmica nodosa B. Adhesions of fallopian tube C. Hydrosalpinx D. Contrast intravasation American College of Radiology
  9. 9. Section VII – Genitourinary Tract Radiology Question #173 Rationales: A. Incorrect. Salpingitis isthmica nodosa involves the isthmic portion of the fallopian tube. Hysterosalpingogram will reveal small outpouchings of contrast outside the expected lumen of the tube. It is seen in 4% of infertility cases. It indicates scarring and is associated with an increased incidence of ectopic pregnancy. B. Incorrect. Adhesions or clumping of a fallopian tube cause convolution of the tube but not the appearance of multiple serpentine structures in the expected location of the isthmic portion of the tube. C. Incorrect. A hydrosalpinx is a dilated, fluid-filled fallopian tube. Usually the ampullary portion of the tube is dilated. The fallopian tube may or may not be obstructed. D. Correct. Contrast intravasation into the uterine wall causes multiple serpentine venous structures to fill adjacent to the uterus. The contrast-filled veins often mimic the appearance of the fallopian tube. Often venous intravasation occurs when the fallopian tube is blocked, as in this case. Confirmation occurs after waiting 2-3 minutes, in which time the contrast dissipates from the veins. Contrast in a fallopian tube would not change in density in that time. Unfortunately, once venous intravasation occurs, further attempts to visualize the tube are futile since the intravasation usually occurs again with the next immediate injection. Citations: Ubeda B, Paraira M, Alert E, Abuin RA. Hysterosalpingography: Spectrum of normal variants and nonpathologic findings. AJR 2001;177:131-135. Diagnostic In-Training Exam 2005
  10. 10. Section VII – Genitourinary Tract Radiology Figure 5A Figure 5B American College of Radiology
  11. 11. Section VII – Genitourinary Tract Radiology 174. You are shown images from an IVU (Figure 5A) and a CT (Figure 5B) of a 35-year-old woman with frequent urinary tract infections. Which one of the following is the MOST likely diagnosis? A. Focal renal infarct with scar B. Focal acute pyelonephritis C. Obstructive uropathy D. Reflux nephropathy Question #174 Findings: IVU demonstrates complete duplication of both the right and left collecting systems. There is dilatation of both lower pole-collecting systems, right more than left. The right lower pole calyces are blunted. The CT image demonstrates cortical thinning of the lower pole of the right kidney overlying a dilated calyx that shows a contrast-urine level confirming it is a dilated calyx. The combination of cortical scarring overlying a dilated calyx is typical of reflux nephropathy. Rationales: A. Incorrect. A focal renal infarct may produce a cortical scar in the chronic stage, but generally there is not underlying calyceal dilatation. B. Incorrect. Focal, acute pyelonephritis can produce a region of decreased enhancement or low density in the kidney after IV contrast. However, the focal inflammatory process should not demonstrate a cystic nature that was seen on this exam as confirmed by the fluid-contrast level. C. Incorrect. Ureteral obstruction could produce similar findings of cortical atrophy and dilated collecting system. However, in cases with completely duplicated collecting systems, the lower pole moiety more commonly is complicated by reflux than by obstruction. Also, the focal cortical thinning over the calyces (as opposed to dilated system with generalized cortical thinning) favors reflux. D. Correct. Completely duplicated collecting systems often have renal complications associated with the ureteral duplication. The ureter draining the lower pole moiety typically enters the bladder slightly above and more lateral to the normal position on the trigone and this predisposes that ureter to reflux. The upper pole moiety enters the bladder inferiorly and medially (Meyer-Weigert Law) and can be complicated by obstruction. The upper pole moiety ureter can also insert ectopically outside of the bladder and this is also typically associated with obstruction. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Diagnostic In-Training Exam 2005
  12. 12. Section VII – Genitourinary Tract Radiology 175. Which one of the following BEST characterizes an adrenal lesion as a benign adenoma? A. Attenuation less than 10 HU on non-contrast CT B. Enhancement washout less than 50% on delayed contrast-enhanced CT C. Increase in signal on out-of-phase images using chemical shift MRI technique D. Attenuation greater than 50 HU on delayed contrast-enhanced CT Question #175 Rationales: A. Correct. Approximately 80% of benign adrenal adenomas contain adequate intracellular lipid to give HU less than 10 on noncontrast CT. This is generally accepted as definitive evidence of benignity. B. Incorrect. A small percentage of benign adenomas do not have adequate intracellular lipid to give attenuation values less than 10 on noncontrast CT. In these cases, intravenous contrast can be given and washout characteristics studied. Metastases tend to “hold” onto contrast longer than benign adrenal adenomas. Thus, adenomas have greater enhancement washout {[(E-D)/(E-U)]x100}, where E is enhanced attenuation value, D is delayed enhancement value, and U is the unenhanced attenuation value, and the accepted threshold value for a benign adrenal adenoma is greater than 60% washout. Washout less than 60% would be indeterminate and other lesions such as metastases would have to be considered. If unenhanced CT has not been performed, a relative enhancement washout can be calculated {[(E-D)/E]x100}, and greater than 40%-50% indicates benign adenoma. C. Incorrect. Chemical shift MRI imaging uses the same physiological principles as noncontrast CT in evaluating an adrenal nodule. Intracytoplasmic lipid in a benign adenoma results in cancellation or loss of signal on out-of-phase images rather than no change or increase in signal intensity. D. Incorrect. Attenuation values of 30-40 HU or less on delayed, contrast-enhanced CT images almost always indicate a benign adenoma. An attenuation value of greater than 50 HU would be indeterminate. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Dunnick NR, Korobkin M. Imaging of adrenal incidentalomas: Current status. AJR. 2002:179. American College of Radiology
  13. 13. Section VII – Genitourinary Tract Radiology 176. What is the classification of a renal cyst with complex septations and dense calcification? A. Bosniak I B. Bosniak II C. Bosniak III D. Bosniak IV Question #176 Rationales: A. Incorrect. Bosniak I cysts are simple cysts and have no septations or calcifications. These require no further evaluation. B. Incorrect. Bosniak II cysts have some atypical features, but are most likely benign. This group of cysts can have thin septations or calcifications but not complex septations or dense calcifications. Some lesions in this group are followed (subgroup IIF). Hyperdense, nonenhancing cysts are included in the Bosniak II category. C. Correct. Bosniak III cysts can have dense calcifications, complex septations, and multiloculated cysts. This group cannot be distinguished from malignancy, and often these lesions require surgical exploration. D. Incorrect. Bosniak IV cystic masses have features which strongly suggest malignancy, such as an enhancing solid component or thick irregular walls. Lesions in this category are treated as presumed renal carcinomas. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Diagnostic In-Training Exam 2005
  14. 14. Section VII – Genitourinary Tract Radiology 177. Concerning congenital ureteropelvic junction (UPJ) obstruction, which one of the following is TRUE? A. It is an uncommon cause of hydronephrosis in children. B. Urinary tract infection is the most common presentation. C. Females and males are affected equally. D. The presence of crossing vessels decreases the success rate of pyeloplasty. Question #177 Rationales: A. Incorrect. It is the MOST common cause of hydronephrosis in children. B. Incorrect. UPJ obstruction is being discovered increasingly in the prenatal period due to frequent use of obstetric ultrasound. When detected due to symptoms or signs, congenital ureteropelvic junction obstruction most often presents in infancy or childhood with an abdominal mass, flank or abdominal pain, failure to thrive, or nonspecific gastrointestinal complaints. Infection, hypertension, hematuria, and stone formation less commonly are the cause for the child to come to medical attention. In a significant number of cases, the disorder is clinically silent into adulthood, when hematuria, flank pain, fever, or rarely, hypertension, are the presenting clinical symptoms. Pain in adults is often episodic and in some cases may only present by high urine flow rates such as those produced by beer drinking. C. Incorrect. Males are affected more than females by 2:1. D. Correct. Crossing vessels are seen in only 15%-20% of cases but significantly reduce the success of pyeloplasty. Thus, many advocate the use of CT for preoperative planning. Citations: Davidson AJ, Hartman DS, eds. Radiology of the Kidney and Urinary Tract. Philadelphia, PA: W.B. Saunders, 1984. Herts BR. Helical CT and CT angiography for the identification of crossing vessels at the ureteropelvic junction. Urol Clin North Am. 1998;25(2):259-269. Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. American College of Radiology
  15. 15. Section VII – Genitourinary Tract Radiology 178. Regarding intravaginal testicular torsion, which one of the following is TRUE? A. Color Doppler is more sensitive than power Doppler for detecting flow. B. It is associated with an abnormal mesenteric attachment bilaterally. C. It accounts for 70 % of cases of acute scrotal pain in adolescents. D. Symmetric homogeneous echogenicity of the testes excludes the diagnosis. Question #178 Rationales: A. Incorrect. Power Doppler is more sensitive than color Doppler for detecting flow, especially in neonates and young boys. Power Doppler shows superiority in demonstrating intratesticular vessels. Power Doppler is limited somewhat by being more sensitive to patient motion than color Doppler. B. Correct. Cases of intravaginal torsion are caused by a bell-clapper deformity of attachment of the mesentery to the testis. The abnormality is bilateral in nearly all cases. C. Incorrect. Testicular torsion only accounts for 30% of cases of scrotal pain in boys age 12-18. Epididymo- orchitis or torsion of an appendix testis/epididymis are much more common causes of scrotal pain. D. Incorrect. In early torsion (when most critical to detect torsion to permit salvaging the testicle), testes may have normally preserved gray-scale appearance. Later gray-scale ultrasound may demonstrate decreased echogenicity of the testis, testicular swelling or reactive hydrocele. Early on, the sonographic diagnosis of testicular torsion relies on the demonstration of decreased or absent flow in the torsed testis on color or power Doppler. Citations: Dogra VS, Gottlieb RH, Oka M, Rubens DJ. Sonography of the scrotum. Radiology. 2003;227(1):18-36. Diagnostic In-Training Exam 2005
  16. 16. Section VII – Genitourinary Tract Radiology 179. Concerning blunt trauma to the bladder, which one of the following is TRUE? A. Intraperitoneal rupture accounts for the majority of cases. B. Less than 20% of extraperitoneal ruptures have pelvic fractures. C. Intraperitoneal rupture is typically treated with surgical repair. D. CT with intravenous contrast can exclude major bladder injury. Question #179 Rationales: A. Incorrect. Extraperitoneal bladder ruptures account for 80%-90% of major bladder injuries. Intraperitoneal ruptures account for 10%-20% of major bladder injuries. B. Incorrect. Extraperitoneal bladder ruptures are almost always associated with pelvic fractures and many are thought to be due to bladder laceration by the fracture fragments. (Although other causes of extraperitoneal bladder injury have also been suggested, such as stress applied to the puboprostatic ligaments causing the bladder wall to tear.) C. Correct. Intraperitoneal bladder rupture is typically treated with surgical repair of the tear and diverting vesicostomy. D. Incorrect. Even delayed images of the bladder with CT and intravenous contrast are not adequate to exclude major bladder injury. This is because there is inadequate distension of the bladder. At least 300 ml of fluid is required to adequately distend the bladder and evaluate for extravasation. Citations: Dunnick NR, Sandler CM, Newhouse JH, Amis Jr SE. Textbook of Uroradiology. 3rd ed. Philadelphia, PA: Lippincott, Williams, & Wilkins; 2001. Vaccaro JP, Brody JM. CT cystography in the evaluation of major bladder trauma. Radiographics. 2000;20:1373-1381. American College of Radiology