GENITOURINARY IMAGING 2 Flashcards

Question

What is the management of this lesion?

Answer 1

Oncocytoma These tumors arise from oncocytes (epithelial cell) of the proximal tubule. Although the majority of lesions are well differentiated and benign, these tumors are usually resected because of their malignant potential and the difficulty in differentiating them from RCC preoperatively. Can consider performing biopsy followed by observation in poor surgical candidates. Represent 5% of renal tumors. Case courtesy of Dr Paul Simkin, Radiopaedia.org, rID: 32824

Answer 2

**_Milk of Calcium Cyst_** * Not a true cyst but a calyceal diverticulum, which may be communicating or closed off * Contains layering calcific granules (calcium carbonate) * No pathologic consequence * Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org, rID: 62623 * Case Discussion * A 17mm non-enhancing cyst like lesion is noted adjacent to middle calyces of left kidney; accompanied with dependent hyperdense material. * Features on CT scan are compatible with left renal milk of calcium cyst. Considered an incidental benign finding that does not require further treatment unless symptomatic. * **_Radiopaedia_** * Renal milk of calcium cysts refer to the appearance of a calcium precipitate found either within a calyceal diverticulum, that has lost communication with the collecting system, or within a simple renal cyst. * Clinical presentation * Renal milk of calcium cysts are typically asymptomatic. * Radiographic features * Plain radiograph * on erect or decubitus films, renal milk of calcium cysts have a characteristic crescentic opacity with a sharp upper border * will change shape to a more oval-shaped opacity on supine projections * Ultrasound * dependent echogenic material within a hypoechoic cyst that demonstrates reverberation artifact * posterior shadowing is present when large volumes of milk of calcium are present * more common in the upper pole of the kidneys * Treatment and prognosis * Considered an incidental benign finding that does not require further treatment unless symptomatic. * Differential diagnosis * On supine plain radiographs, a renal milk of calcium cyst may be mistaken for a renal calculus. * Milk of calcium can also occur within the gallbladder.

Answer 3

* Hematuria, 50% * Flank pain, 40% * Palpable mass, 35% * Weight loss, 25%

Answer 4

Perinephric Cyst * Located beneath the renal capsule * Not true cysts; represent extravasated urine trapped beneath renal capsule (pseudocysts, uriniferous cysts, urinoma) * CT scan of abdomen shows multiple perinephric cystic fluid collections compressing both the kidneys. * https://www.researchgate.net/figure/CT-scan-of-abdomen-shows-multiple-perinephric-cystic-fluid-collections-compressing-both\_fig2\_275123460

Answer 5

**_Imaging Features_** * **Small kidneys** (as opposed to large kidneys in polycystic disease) * **Multiple small (**\<2 cm) cysts in medulla * **Cysts may be too small to resolve** by imaging, but their multiplicity will result in increased medullary echogenicity and apparent widening of central sinus echoes. * **Cortex is thin and does not contain cysts.** * **No Calcifications**

Answer 6

Orientation and Size of Kidneys Kidneys are 3 to 4 lumbar vertebral bodies in length, 12–14 cm long and 5–7 cm wide. Intravenous pyelograms (IVPs) overestimate the true renal length because of magnification and renal engorgement from osmotic diuresis.

Answer 7

* Renal parenchymal tumors * Renal cell adenocarcinoma, 80% * Wilms tumor, 5% * Adenoma (thought to represent early RCC) * Oncocytoma * Nephroblastomatosis * Mesoblastic nephroma * Mesenchymal tumors * Angiomyolipoma (AML) * Malignant fibrous histiocytoma (MFH) * Hemangioma * Other rare tumors * Renal pelvis tumors * Transitional cell carcinoma (TCC) \<10% * Squamous cell carcinoma * Undifferentiated adenocarcinoma tumors * Benign tumors: * papilloma * angioma, * fibroma * myoma * polyp * Secondary tumors * Metastases * Lymphoma

Answer 8

Imaging findings * Mass lesion: renal contour abnormality, calyceal displacement * Large variability in signal characteristics on noncontrast CT and MRI depending on the degree of hemorrhage and necrosis * Contrast enhancement is usually heterogeneous; strong contrast enhancement (\>15 HU) * Calcification, 10% * Cystic areas (2%–5% are predominantly cystic) * Filling defects (clots, tumor thrombus) in collecting system and renal veins. * US appearance * Hyperechoic: 70% of tumors \>3 cm, 30% of tumors \<3 cm * Hypoechoic * Angiography * 95% of tumors are hypervascular. * Caliber irregularities of tumor vessels are typical (encasement). * Prominent AV shunting, venous lakes * Angiography may be useful for detection in complicated and equivocal cases: * Small tumors * Underlying abnormal renal parenchyma * VHL disease * Preoperative embolization

Answer 9

Imaging Features * Central stellate scar (CT) and spoke wheel appearance (angiography) are typical but not specific (also seen in adenocarcinoma). * Well-defined, sharp borders * Radiographically impossible to differentiate from RCC * Case Discussion * A nephrectomy was undertaken for this large renal mass. * It was a renal oncocytoma on the surgical pathology specimen. * This typically has a central stellate scar, however the appearances are very similar to the central necrosis observed in many renal cell carcinomas. * Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 78952

Answer 10

Lymphoma Incidence of renal involvement in lymphoma is 5% non-Hodgkin lymphoma [NHL] \> Hodgkin disease at diagnosis and 30% at autopsy.

Answer 11

**Horseshoe Kidney** * The two kidneys are connected across the midline by an isthmus. * This is the most common fusion anomaly (other fusion anomalies: cross-fused ectopia, pancake kidney). * The isthmus may contain parenchymal tissue with its own blood supply or consist of fibrous tissue. * **Imaging Features** * Abnormal axis of each kidney with lower calyx more medial than upper calyx * Bilateral malrotation of renal pelvises in anterior position * Isthmus lies anterior to aorta and inferior vena cava (IVC) but behind inferior mesenteric artery (IMA) Case courtesy of Dr Aditya Shetty, [Radiopaedia.org](https://radiopaedia.org/). From the case [rID: 27958](https://radiopaedia.org/cases/27958)

Answer 12

Stone Protocol * Noncontrast CT of the abdomen and pelvis using 5 mm slice thickness * Coronal and sagittal reconstructions with 3 mm slice thickness **CT KUB** **Last revised by Dr Vikas Shah◉ on 06 Jul 2021** * Computed tomography of kidneys, ureters and bladder (CT KUB) is a quick non-invasive technique for diagnosis of urolithiasis. It is usually considered the initial imaging modality for suspected urolithiasis in an emergency setting 1. * Indications * suspected urolithiasis * haematuria (typically in conjunction with a CT-IVU) * flank pain * Purpose * The purpose of CT KUB is primarily to assess for the presence of urolithiasis. Location of the stone, size, and secondary signs of renal tract obstruction can then be used to gauge the likelihood of passage and guide further management 3. Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 84479

Answer 13

Percutaneous Nephrostomy (Pcn) * Refers to percutaneous drainage of renal collecting system by catheter placement. Complications: 2%–4% (extravasation of contrast, bleeding) * Indications * Hydronephrosis (acute, subacute obstruction) * Pyonephrosis Technique ( Fig. 4.2 ) 1. Preprocedure workup: Check coagulation status. Cefazolin 2 g IV \< 120 kg; 3 g IV \> 120 kg and gentamicin 120 mg IV × 1 Penicillin-allergic patients: vancomycin as above and aztreonam 2 g IV Review all radiographs and determine on plain film where kidneys are located, especially in relation to colon, spleen, and pleural reflections. 2. Local lidocaine. Under US guidance, place a 20-gauge introducer system into a posterior, lower pole calyx. 3. The inner needle stylet can be removed and free flow of urine checked. Aspirate a small amount for cultures and to mildly decompress the system when urine is obtained. 4. Attach connector tubing and inject a small amount of contrast to confirm positioning at the tip of a calyx. Detach the connector tubing carefully to ensure that the needle stays in place. 5. Use the microwire to gain access to the renal pelvis. Remove the introducer needle, and insert the plastic sheath that comes with the set. 6. Place a 0.038 Amplatz wire through the sheath into the renal collecting system and down the ureter. Depending on the anatomy/obstruction, it may be necessary to use different wire combinations. 7. Dilate skin up to 12 Fr. 8. Pass 8–10-Fr percutaneous nephrostomy (PCN) catheter over guidewire. Remove stiffener and guidewire. Coil pigtail. Inject contrast to check position of catheter within the renal pelvis. Cut thread. 9. In the setting of infection, complete evaluation of the ureter via an antegrade injection is best deferred to a second visit.

Answer 14

Associated Findings * Hepatic cysts, 70% * Intracranial berry aneurysm, 20% * Cysts in pancreas and spleen, \<5%

Answer 15

Paraneoplastic syndrome: * HTN (renin), * erythrocytosis (erythropoietin), * hypercalcemia (PTH), * gynecomastia (gonadotropin), * Cushing syndrome (ACTH)

Answer 16

Imaging Features * Multiple lymphomatous masses (hypoechoic, hypodense), 50% * Diffuse involvement of one or both kidneys * Adenopathy Case courtesy of Dr Abdallah Al Khateeb, Radiopaedia.org, rID: 47824

Answer 17

Therapy * Radical nephrectomy (entire contents of Gerota fascia are removed) * Ablation (radiofrequency, microwave, cryo) * Partial nephrectomy * Chemotherapy * Radiotherapy is used for palliation only.

Answer 18

Left Bifid Renal Pelvis * One pelvis drains upper pole calyces; * the other drains the middle and lower pole calyces. * The two pelvises join proximally to the ureteropelvic junction (UPJ). * Incidence: 10% of population. * No complications. Case courtesy of Assoc Prof Craig Hacking, Radiopaedia.org, rID: 55987

Answer 19

Bone, 20% (classic lesions are lytic, expansile) Bone Metastases Bone metastases appear in 30% of all patients with disseminated RCC (23). Most bone metastases are associated with severe comorbidity, causing pain and pathologic fractures with subsequent functional impairment. Recent studies have reported that these patients have a high incidence of spinal cord and nerve root compression (27). On CT images, bone metastases appear as large expansile lytic lesions, most commonly located in the axial skeleton; usually the vertebral bodies are involved more often than the pedicles. Lytic lesions are usually extremely destructive and may be associated with an enhancing soft-tissue component (Fig 4) (13).

Answer 20

Ureteral Duplication ( Fig. 11.38 ) * Two ureters drain one kidney **(incidence 1 : 150).** * Duplications may be incomplete (“Y” ureter) or complete: * Orthotopic ureter: * drains lower pole and enters bladder near trigone * Ectopic ureter: * drains upper pole and enters bladder inferiorly and medially (Weigert-Meyer rule); * the ectopic ureter may be stenotic and obstructed. * **Complications** * **Reflux in orthotopic ureter, causing urinary tract infection (UTI)** * **Obstruction of ectopic ureter** * **Ureterocele** * **Uterocele. A reformatted coronal image from a CT urogram demonstrates a partially duplicated collecting system on the left side with two ureters (black and white arrows) that join at the pelvic inlet and insert as one ureter into the bladder. At the insertion of the ureter, there is a saccular collection of contrast with a halo of lucency surrounding it characteristic of a ureterocele.** * **http://www.learningradiology.com/notes/gunotes/ureterocoelecorrect.htm**

Answer 21

• * Nephroptosis * AKA * (floating or wandering kidney): * Intro * acquired condition with excessive descent of the kidney in erect position; * differs from congenital pelvic kidney in that the paired renal arteries arise from their typical anatomic location. * Definition * descent of the kidney more than 5 cm or two vertebral bodies when the patient moves from a supine to upright position during IVU 1,2. * Displacement can also occur medially across the midline, so-called medial nephroptosis 8,9. A 2013 case report even demonstrated anterior displacement 10. * Clinical presentation * It may be present in up to 20% of young, slim females and is mostly asymptomatic 2. * It is more often seen on the right side, in up to 20%, is bilateral. * Symptoms * may include flank pain on standing that is relieved on lying down, with the hypothesis being that movement of the kidney causes intermittent renal tract obstruction 1. * Rarely it can cause intermittent nausea, vomiting, hypotension, oliguria and proteinuria, a syndrome known as **Dietl's crisis** 5. * It may occur in childhood as well 11,12. * Radiographic features * Intravenous urography, renal scintigraphy with various tracers, CT and ultrasound may all allow for the diagnosis (performed supine and upright, lateral decubitus in medial ptosis) 3,4,8,9. * Colour Doppler ultrasound (CDI) with estimation of renal resistive index (RI) has been shown to be sensitive in detecting renal blood flow impairment and may thus aid in decision for laparoscopic nephropexy 3. * Treatment and prognosis * Laparoscopic nephropexy, usually reserved for cases with vascular and/or obstructive renal impairment, has been shown to be successful in relieving symptoms caused by renal compromise 3,6,7,12. * Case courtesy of Dr Sami Elhinnawi, Radiopaedia.org, rID: 56632

Answer 22

Horseshoe Kidney * The two kidneys are connected across the midline by an isthmus. * This is the most common fusion anomaly (other fusion anomalies: cross-fused ectopia, pancake kidney). * The isthmus may contain parenchymal tissue with its own blood supply or consist of fibrous tissue. * Complications * Obstruction, infection, calculus formation in 30% * Increased risk of renal malignancies, especially Wilms tumor * Increased risk of traumatic injury Case courtesy of Dr Aditya Shetty, [Radiopaedia.org](https://radiopaedia.org/). From the case [rID: 27958](https://radiopaedia.org/cases/27958)

Answer 23

* INHERITANCE * AD * GENES * TSC1,TSC2 * RENAL * Bilateral renal cysts that vary in number and size; * bilateral angiomyolipomas * (may not contain appreciable fat at imaging) * renal cell carcinoma (rare) * HEART * Cardiac rhabdomyomas; * CNS abnormalities * (eg, corti-cal tubers, * subependymal nodules, * subependymal giant cell astrocytoma); * ABDO * hepatic angiomyolipomas; * pancreatic neuroendocrine tumors; * LUNGS * lymphangioleiomyomatosis; * multifocal micronodular pneumocyte hyperplasia; * BONES * osseous sclerotic lesions (bone islands); * VESSELS * (eg, abdominal aorta aneurysms)

Answer 24

**_Renal Mass Biopsy Criteria_** Most solid and complex cystic masses suspicious for primary renal malignancy are **ultimately surgically removed.** Established criteria for renal mass biopsy include: * Established 1. Renal mass presenting in a patient with other primary malignancy to rule out metastasis 2. Rule out focal pyelonephritis 3. Comorbid disease increases risk for surgery (e.g., solitary kidney) 4. Unresectable mass, confirmation of diagnosis before systemic therapy * Emerging 1. Confirmation of diagnosis before percutaneous ablation 2. Hyperdense homogeneously enhancing mass, which may be a lipid-poor AML 3. Bosniak category 3 lesion 4. Multiple solid masses

Answer 25

Septum of Bertin (upper pole 90%, bilateral 60%); associated with bifid renal pelvis Case courtesy of Dr Hani Makky Al Salam, Radiopaedia.org, rID: 9780

Answer 26

The renal axis parallels axis of psoas muscles.

Answer 27

Renal Pedicle ( Fig. 4.1 ) 1. Renal artery 2. Renal vein 3. Collecting system and ureter 4. Lymphatics

Answer 28

Tumors **\>3 **cm can be difficult to treat with current ablation technology. Larger tumors often require multiple overlapping ablations, which increase the risk of complications. Tumors **\>5 c**m have a higher incidence of recurrence. Complete ablation of **central** tumors is difficult owing to heat sink effect of large vessels within the renal hilum. Also, ablating **central** tumors poses the risk of injury to the collecting system or ureter. **Anterior** location of tumors can lead to **colonic** injury. This can be avoided with hydrodissection. Tumors are ablated under g**eneral anesthesia or deep conscious sedation.** **CT** is the preferred modality for renal tumor ablation because of high spatial resolution and its ability to image structures that need to be avoided. **US** can also be used for superficial and peripheral exophytic lesions.

Answer 29

CT Protocols of the Kidney/Ureters Hematuria Protocol Single bolus CT technique * Phase 1: Noncontrast CT of the abdomen and pelvis, including KUB * Single bolus (100–150 mL, 300–320 mg of iodine/mL) of IV contrast material at 2–4 mL/s * Early images of kidney in nephrographic phase * Excretory phase images (5 min following injection) through KUB

Answer 30

Persistent fetal lobulation: scalloped appearance of renal outline; adjacent calyx is normal Case courtesy of Dr Chris O'Donnell, Radiopaedia.org, rID: 41364

Answer 31

Junctional parenchymal defect: * fusion defect in upper pole of kidney that does not represent a scar; * echogenic linear defect extends from sinus; * commonly seen in pediatric patients Case courtesy of Dr Amir Rezaee, Radiopaedia.org, rID: 43561

Answer 32

Collecting System * Minor calyces: most kidneys have 10–14 minor calyces. * Major calyces * Renal pelvis: may be completely within the renal sinus or partially “extrarenal.”

Answer 33

Cyst Ablation If a symptomatic cyst recurs after aspiration, percutaneous ablation may be considered to avoid surgery. 1. Place a 20-gauge needle into cyst and measure total volume aspirated. Some interventional radiologists prefer a small pigtail catheter. 2. Inject contrast to exclude communication with the collecting system, which would preclude alcohol ablation. 3. Inject absolute ethanol, 25% of the volume of cyst fluid aspirated. 4. Leave ethanol in place 15–20 min, turning the patient to different positions to maximize wall contact of alcohol with different surfaces. 5. Aspirate residual ethanol.

Answer 34

Inverted Papilloma • No malignant potential **_• 20% are associated with uroepithelial malignancies elsewhere, most commonly in bladder._** * General Information * It is generally considered a benign histologic lesion; however, it may harbor malignant change. * Median age is 55. * Frequently presents with hematuria. * Imaging * Intravenous Pyelography * Solitary solid, sessile or pedunculated, polypoid lesion * Ultrasonography * Echogenic mass within the ureteral lumen resulting in partial or complete urinary tract obstruction * Computed Tomography * Hypodense mass seen as filling defect in ureteral lumen. Delayed phase images at CT urography may clearly demonstrate. * Pathology * Inverted papilloma is more common in the ureter than the renal pelvis. It is also more common in older males. * Inverted papilloma consists of typical urothelium that forms trabeculae which undermine the overlying mucosa. It is morphologically similar to its counterpart in the bladder. * Differential Diagnosis * Benign and malignant neoplasms of ureter, radiolucent stones, and blood clot * **_Pearls and Pitfalls_** * **Inverted papillomas of the renal pelvis and ureter may be associated with urothelial neoplasms elsewhere in the urothelial tract.** * **Urothelial carcinomas may coexist with or arise within inverted papillomas.** * Inverted papillomas may recur. * https://radiologykey.com/neoplasms-of-the-renal-pelvis-and-ureter-2/ * https://www.urotoday.com/recent-abstracts/urologic-oncology/bladder-cancer/108694-inverted-papilloma-a-rare-and-benign-cause-for-upper-urinary-tract-neoplasia.html

Answer 35

Cyst Aspiration * Indications for Cyst Aspiration * Diagnosis * Complex, high-density cyst (type 2) ≥3 cm * Evaluate fluid for character, as well as cytology * After aspiration, inject contrast (“cystogram”) and obtain multiple projections so that all surfaces of the wall are smooth. * Therapy * Most commonly performed for large cyst obstructing collecting system or causing dull, aching pain or, rarely, HTN **(Page kidney)** * If the cyst is simple and the fluid is clear, yellow, and free-flowing, laboratory analysis is not necessary. Bloody or brownish fluid should be sent for cytology.

Answer 36

* von Hippel– Lindau syndrome * AD * GENE * VHL * RENAL * Multiple bilateral renal cysts * (un- common in childhood); * renal cell carcinoma * (commonly bilateral and multifocal) * BRAIN * CNS (brain and spinal cord) hemangioblasto- mas; * **ABDO (Think: Lots of "P's")** * pancreatic cysts and cystadenomas; * pancreatic neuroendocrine tumors; * pheochromocytomas and * paragangliomas

Answer 37

* DICER1 muta- tion * INHERITANCE * AD * GENE * DICER1 * RENAL FINDINGS * Complicated renal cystic masses ie (cystic nephromas) * ASSOCIATIONS * SOFT TISSUES * Embryonal rhabdomyosarcomas; * most common soft tissue sarcoma occurring in children. * ERMS = type of **small round blue cell tumor** * OVARY * ovarian sex cord– stromal tumors; * BRAIN * pituitary tumors; * LUNGS * pleuropulmonary blastomas; * THYROID * multinodular goiter, * carcinoma

Answer 38

Renal Pelvis Tumors Most tumors arising from the renal pelvis are malignant with **transitional cell cancer** being the most common tumor. **Papillomas** are the most common benign tumor. * **Case Discussion TCC** * Gross pathological sample * Nephrectomy ( cut ). * Large tumour occupying the renal pelvis extending into the upper and mid pole calyces. * Transitional cell carcinoma is more commonly associated with the bladder, but can effect any part of the genitourinary tract. * In this case it was identified on a CT performed for other purposes. * Haematuria is the main symptomatic presentation. * Imaging of the upper tracts is best undertaken with either CT-IVU or split bolus technique imaging. * Images courtesy of Department of Pathology, RIPAS Hospital, Brunei. * Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 28184

Answer 39

Cross-fused ectopia: the ectopic kidney is inferior Case courtesy of Dr Ahmed Abdrabou, Radiopaedia.org, rID: 32283

Answer 40

Retrograde Pyelogram A catheter is placed in the distal ureter via cystoscopy and contrast is administered via the catheter by hand injection to opacify the collecting system (no parenchymal opacification). This technique is primarily used for percutaneous ureterolithotomy (PUL) access and difficult nephrostomy placements.

Answer 41

Lobar dysmorphism: * abnormally oriented lobe between upper and middle calyces; * always points to posterior calyx, * which is key to diagnosis on CT or IVP. * By US this entity is indistinguishable from column of Bertin. [https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1442-2042.1995.tb00456.x](https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1442-2042.1995.tb00456.x)

Answer 42

Simple Cysts ( Fig. 4.3 ) * Simple cysts (**in \>50%** of population \>50 years) probably arise from obstructed tubules or ducts. * **They do not, however, communicate with the collecting system.** * Most commonly asymptomatic; rare findings include hematuria (from cyst rupture), hypertension (HTN), and cyst infection. * Mass effect from large cysts may cause dull ache or discomfort.

Answer 43

Renal Mass Protocol Phase 1: noncontrast CT images of abdomen Phase 2: corticomedullary phase, 25–30 s after contrast injection, through kidneys Phase 3: nephrographic phase, 60–80 s after injection https://radiopaedia.org/articles/renal-mass-protocol-ct?lang=gb Terminology For some departments and/or radiologists, a renal mass protocol may only include a non-contrast, nephrogenic phase exam. For others, it may consist of a corticomedullary phase (40-60 second delay) and/or an excretory phase (5-10 minute delay). Indications Indeterminate renal mass, renal adenocarcinoma, metastasis, monitoring of known renal mass. Purpose * The purpose of this exam is to assess the location and composition of a renal mass. * non-contrast scan is best to determine the HU of homogenous renal mass or masses containing macroscopic fat 1 * corticomedullary phase is best to delineate subcategories of renal cell carcinomas further * nephrogenic phase is best for optimal enhancement of the renal parenchyma, including the renal medulla, and will demonstrate enhancing components of a mass excretory phase will demonstrate enhancement of calyces, renal pelvis and ureters. Many institutions will perform this around 5 minutes to demonstrate opacification of the ureters

Answer 44

Localized Cystic Disease Benign, acquired unilateral condition characterized by multiple cysts of varying size. Cysts, separated by normal renal parenchyma, may occupy the entire kidney or be more localized. Calcification of cyst walls may be present but the cyst wall has to be thin; it does not compromise renal function. No surgery necessary. Radiographic features Renal cysts in localised cystic renal disease can involve segments of the kidney or the entire kidney but are always unilateral. The key feature is that the cysts are separated by normal or atrophic renal parenchyma. Unlike ADPKD, localised cystic renal disease is unilateral, and other organs do not have cystic involvement. In contrast to cystic nephroma, no capsule is seen around the cysts. Case courtesy of Dr Huda B. Gharbia, Radiopaedia.org, rID: 61807 Case Discussion There are numerous cystic lesions in the left kidney. They appear slightly hyperintense on T1W images, and show dark signal in T2W images, with show no signal loss T1 out phase sequences. There are few cysts appear hypointense T1W and hyperintense in T2W images. Hyperattenuating lesions relative to renal parenchyma and T2W markedly hypointense signal, with invisible fat content denoting blood or proteinatious content cysts with others few simple cysts, suggestive of localised renal cystic disease.

Answer 45

* ARPKD * INHERITANCE * AR * GENE * PKHD1 (ciliopathy) * RENAL * Diffuse uniform involvement of the kidney with many tiny microcysts caused by collecting duct ectasia; * marked nephromegaly; * can see larger discrete cysts; * commonly causes chronic kidney disease in childhood * ABDO * Ductal plate malformations * (eg, congenital hepatic fibrosis); * extrahepatic bile duct dilatation (rare); * splenomegaly, * portosystemic varices, ascites * (caused by portal hypertension) * LUNGS * pulmonary hypoplasia

Answer 46

Renal Cell Carcinoma Synonyms: * RCC, * hypernephroma, * clear cell carcinoma, * malignant nephroma

Answer 47

Drip-Infusion Nephrotomogram With drip infusion, the nephrogram persists longer, allowing more time for nephrotomography and special views, if necessary. Today, this is much less commonly performed than the bolus technique or computed tomography (CT). If calcifications are seen on the renal outlines, scout oblique radiographs can be obtained to determine the exact location relative to the kidneys. Technique 1. KUB and preliminary tomogram of kidneys (starting at 8 cm from back) 2. Drip infusion of 300 mL of Urovist 14% (or Conray-30) or 150 mL of Isovue 300 (or Omnipaque 300) 3. Obtain tomograms after 150 mL has been given. Usually 7 to 9 cuts are obtained. 4. Postinfusion KUB and both oblique views 5. Coned bladder view 6. Postvoid KUB

Answer 48

Metastases Incidence: 20% of cancer patients at autopsy. Common primary lesions are lung, breast, and colon cancer and melanoma.

Answer 49

Associations * Tuberous sclerosis: * 80% of patients with tuberous sclerosis have AML, typically multiple, bilateral lesions. * However, \<40% of patients with AML have tuberous sclerosis. * In the absence of tuberous sclerosis, 5% of all AML patients will have multiple, bilateral AML. * Lymphangiomyomatosis

Answer 50

Three patterns of involvement: 1. Direct extension from retroperitoneal disease (common) 2. Hematogenous dissemination (common) 3. Primary renal lymphoma (i.e., no other organ involvement) is rare, because kidneys do not have primary lymphatic tissue.

Answer 51

**_MRI and RCC_** * **Venous invasion** of tumor is better diagnosed by MRI. * Using a 0.1-mmol/kg dose ofgadolinium (Gd)-chelate, the **percentage of enhancement suggestive of RCC is 15%,** obtained after 2–4 min of contrast administration (1.5T).

Answer 52

* Medullary cystic kidney disease * INHERITANCE * AD * GENES * MCKD1 (now MUC1), * MCKD2 * RENAL FINDINGS * Discrete cysts located in the medulla and at the corticome- dullary junction, * with cortical sparing; * cause of adult-onset chronic kidney disease * ASSOCIATIONS * None

Answer 53

Bolus IVP Today, IVPs are rarely used, but are covered for historical purposes. The bolus administration ensures maximum concentration of contrast media in the kidney. Indication: healthy ambulatory patients (screening type urography [e.g., for urinary tract infection (UTI)]), trauma. Technique 1. Kidney, ureter, bladder (KUB) 2. Inject 100 mL of 30% contrast 3. 1-min and 5-min radiograph of both kidneys 4. 10-min KUB and both obliques 5. Coned bladder view 6. Postvoid KUB Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org, rID: 85286

Answer 54

Uremic Cystic Disease (UCD) AKA: Aquired renal cystic disease (ARCD) * 40% of patients with end-stage renal disease develop renal cysts. * Incidence increases with time on dialysis so that incidence of UCD is 90% in patients on dialysis for 5 years. * Associated complications include: * Increased incidence of RCC * Hemorrhage of cysts * Cysts can regress after successful transplantation. FIGURE 5.25. ARCD with renal cell carcinoma. Multiple small cysts in a patient on long-term dialysis with small kidneys bilaterally. Unenhanced (A) and enhanced (B) CT of the abdomen images demonstrate a large enhancing left renal tumor. FIGURE 5.26. Acquired renal cystic disease. Multiple renal cysts and a perinephric hematoma are identified on this contrast-enhanced CT scan. https://radiologykey.com/renal-cystic-disease-3/ It is easier to examine the native kidneys with CT (Fig. 5.25) and MRI than with ultrasound. Multiple small cysts are seen by CT or MRI in virtually all patients with ARCD. Dystrophic calcifications are common in the renal parenchyma or cyst walls. Bleeding is a common complication, so hemorrhagic cysts and subcapsular or perinephric hematomas are often found (Fig. 5.26). Carcinomas are seen as masses with a density similar to the unenhanced parenchyma. If large (\<3 cm), the masses may be heterogeneous on enhanced images (Fig. 5.27).

Answer 55

* Cortical cysts * Simple cysts * Complicated (complex) cysts * Localized cystic disease of the kidney * Medullary cystic disease (MCD) * Polycystic renal disease * Infantile polycystic disease * Adult polycystic disease * Multicystic dysplastic kidney (MCDK) * Multilocular cystic nephroma (MLCN) * Cysts associated with systemic disease * Tuberous sclerosis * Von Hippel-Lindau (VHL) disease * Miscellaneous cysts * Hydatid * Acquired cysts in uremia * Extraparenchymal cysts * Parapelvic cysts * Perinephric cysts

Answer 56

Right kidney is 1-2cm lower than the left kidney and slightly more lateral.

Answer 57

Autosomal Dominant Polycystic Kidney disease Imaging Features * Kidneys are **enlarged** and contain **innumerable cyst**s, creating a **bosselated** surface. * **Calcification** of cyst walls is common. * Pressure deformities of calyces and infundibula * IVP: **“Swiss-cheese” nephrogram** * Cysts have variable signal characteristics. * CT: hypodense, hyperdense (hemorrhage, protein, calcium) * T1-weighted (T1W): some cysts contain clear, watery fluid (hypointense); others contain blood and protein (hyperintense); layering in some cysts is caused by cellular debris. * **Hepatic cysts**

Answer 58

**_Bosniak Classification_** * Category 1: * benign simple cyst * Simple cysts contain low-attenuation (0–20 HU) fluid and a hairline-thin smooth wall. * Cysts do not contain septations, calcifications, or enhancing nodular soft tissue. * Category 2: * minimally complicated cysts that are benign but have certain radiologic findings of concern. * Includes septated (paper-thin septations) cystic, minimally calcified cysts, high-density cysts. * Fine calcification or a short segment of slightly thickened calcification may be present in the wall or septa. * Hyperattenuating cysts contain more fluid than water attenuation (i.e., \>20 HU). * In general, cysts that measure between 20 and 40 HU are proteinaceous cysts and will show findings of a simple cyst using US; * those with attenuations over 40–50 HU are likely to be hemorrhagic cysts and will be complex under US. * When a hyperattenuating renal mass is encountered on an unenhanced CT scan, the probability of the mass being benign is more than 99% as long as the attenuation is 70 HU or more and the mass is homogeneous. * Category 2F * (the “F” means to follow) * lesions cannot be considered benign without some period of observation. * Slightly more complicated (e.g., may contain multiple, hairline-thin septa that demonstrate perceived [not measurable] enhancement). * May have minimal smooth thickening of the wall or septa. * May contain thick irregular or nodular calcification. * No enhancing soft tissue components. * Hyperattenuating renal masses that exhibit all the features of hyperattenuating cysts but are larger than 3 cm and are completely intrarenal are also included in this category. * **Recommended follow-up is to perform a CT or MR examination at 6 months, followed by yearly studies for a minimum of 5 years.** * Category 3: * complicated cystic lesions that exhibit some radiologic features seen in malignancy * This category includes * multiloculated cystic nephroma, * multiloculated cysts, * complex septated cysts, * chronically infected cysts, * heavily calcified cysts, and * cystic renal cell carcinoma (RCC). * Because these entities are difficult to separate radiologically, surgery is usually performed. * Category 4 lesion: * clearly malignant lesions with large cystic component. * Irregular margins, solid vascular elements

Answer 59

**_Urothelial Papilloma_** Background: Epithelial Tumors of the renal sinus Benign epithelial tumors are urothelial papilloma and inverted papilloma, which are extraordinarily rare and detected incidentally. Malignant epithelial tumors account more than 90 % of all renal pelvis and ureteral tumors. Approximately 90 % of malignant tumors are urothelial carcinomas (transitional cell carcinomas), followed by squamous cell carcinoma (10 %) and adenocarcinoma (less than 1 %). **_Benign Epithelial Tumors:_** * **Urothelial Papilloma** * General Information * Benign exophytic papillary urothelial tumor * Tends to occur in younger patients * Usually presents with gross hematuria * Imaging * Intravenous Pyelography * Radiolucent filling defect in continuity with the wall of the collecting system * Ultrasonography * Echogenic focus within the ureter and renal pelvis associated with the moderate to severe hydronephrosis * Computed Tomography * A ureteral or renal pelvis mass with attenuation in the soft-tissue range of 30–40 Hounsfield units * Magnetic Resonance Imaging * Magnetic resonance urography demonstrates the localization and extent of tumor by showing hypointense filling defect in renal pelvis and ureter on heavily T2-weighted images. * Pathology * Urothelial papilloma in these sites is rare. It is a mucosal lesion composed of a delicate papillary frond lined by typical urothelium of normal thickness. It is morphologically similar to its counterpart in the urinary bladder. * Differential Diagnosis * Papillary neoplasm of low malignant potential is a papillary urothelial neoplasm. Mean age of this disease is 64.6 years. * Transitional cell carcinoma, blood clots, and fungus balls. * Pearls and Pitfalls * Urothelial papilloma tends to occur in younger patients. * MR urography may show benign characteristics of this tumor by demonstrating the absence of periureteral or perirenal invasion. * https://www.ajronline.org/doi/pdf/10.2214/AJR.14.13879 * https://radiologykey.com/neoplasms-of-the-renal-pelvis-and-ureter-2/

Answer 60

Pathology * Clear cell type * (65% of RCC). * Cell origin: * proximal tubule. * Cytogenetic abnormalities: * chromosome 3p deletions, * mutations of VHL gene (tumor suppressor gene) * Papillary cell type * (chromophil) (15%). * Cell origin: * proximal tubule. * Cytogenetic abnormalities: * trisomies of chromosomes 3q, 7, 12, 16, 17, 20; * loss of Y chromosome * Chromophobe cell type (10%). * Cell origin: * intercalated cell of cortical collecting duct. * Cytogenetic abnormalities: * monosomies of chromosomes 1, 2, 6, 10, 13, 17, and 21; –hypodiploidy * Oncocytoma (5%). * Cell origin: * intercalated cell of cortical collecting duct. * Cytogenetic abnormalities: * loss of chromosomes 1 and Y * Unclassified cell type * (5% of RCC). * Sarcomas, collecting duct tumors, others

Answer 61

**_Renal pelvis Transitional Cell Carcinoma_** * Tumors are often multifocal: 40%–80% of patients have bladder TCC. However, only 3% of patients with bladder TCC later develop upper tract TCC. * Radiographic finding: irregular filling defect * Obliteration of renal sinus fat and infiltration of renal parenchyma (faceless kidney) * 60% recurrence on ipsilateral side * 50% have lung metastases. Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 25450

Answer 62

Imaging Features * Septations * Thin septa within cysts are usually benign. * Thick or irregular septa require workup. * Calcifications * Thin calcifications in cyst walls are usually benign. * Milk of calcium: collection of small calcific granules in cyst fluid: usually benign * Thick wall * Usually require surgical exploration * Increased CT density (\>15 HU) of cyst content * Vast majority are benign. * High density is usually due to hemorrhage, high protein content, and/or calcium. * 50% appear as simple cysts using US. * The remainder of patients require a further imaging workup (to exclude soft tissue mass) or occasionally cyst puncture (analyze fluid, inject contrast).

Answer 63

**Wunderlich syndrome.** Case Discussion * Predominantly echogenic lesion involving the upper pole of the right kidney associated with more complex appearing perinephric collection. * CT scan of the abdomen confirms the presence of a fatty lesion in the upper pole of the right kidney consistent with angiomyolipoma complicated by haemorrhage. * Incidental two tiny hepatic haemangiomas. * Perirenal haemorrhage without a history of trauma complicating an angiomyolipoma is known as **Wunderlich syndrome.** * **If perirenal haemorrhage is encountered on ultrasound, a thorough workup should be performed to exclude a bleeding renal cell carcinoma.** * Case courtesy of Dr Hani Makky Al Salam, Radiopaedia.org, rID: 10090

Answer 64

Ureteral spindle: dilatation of middle third of ureter at crossing of iliac vessels

Answer 65

Split bolus CT technique: * Phase 1: noncontrast CT of abdomen and pelvis. Immediately thereafter administer 30 mL of IV contrast and wait 5–10 min. * Phase 2: place patient back on scanner and inject 100 mL of contrast at 2–3 mL/s, and scan patient prone from top of kidneys to pubic symphysis after 100 s. * Phase 2: excretory phase (5 min) through the kidneys is obtained at the same time as the 100-s scan. The initial bolus of 30 mL should now be making its way through the collecting system. [https://radiopaedia.org/articles/split-bolus-technique](https://radiopaedia.org/articles/split-bolus-technique) The split bolus technique is a CT imaging investigation used in patients with haematuria aiming to put together, in a single image acquisition, both the nephrographic and renal excretory phases and thus reducing the radiation dose of the study. It is a CT protocol adopted for some institutions for assessing a patient with haematuria 1,2. Usually, a prior unenhanced study of the abdomen and pelvis in the form of a CT-KUB has been performed or undertaken before the split bolus component, excluding nephrolithiasis as the cause of the haematuria. Then, the patient receives 50 mL of IV contrast followed by an additional 50 mL eight minutes later. Images are then acquired 55 seconds following the second dose of IV contrast. In some centres the patient may be asked to lie in a prone position. This provides contrast imaging of the kidneys to look for a renal mass, such as renal cell carcinoma along with a CT-IVU, allowing for the detection of upper tract disease, such as transitional cell carcinoma. Bladder images are acquired which are insightful, but this should not be a substitute for cystoscopic assessment. The technique has been shown to have a high sensitivity, specificity and accuracy for detecting upper tract tumours 3. Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 60355

Answer 66

Presentation * Right upper quadrant acute pain and tenderness. * Hyperechogenic lesion with sharp borders. * A round lesion with fat density (-75 HU) and only minimal focal enhancement. * Case courtesy of Dr Roberto Schubert, Radiopaedia.org, rID: 16842

Answer 67

* Case Discussion * Mixed fat-solid vascularised giant mass in the renal space with central foci measuring around 40 HU - probable haematoma. Note additional small fat foci in both kidneys and one small focus in the liver. * Mass and right kidney were removed. * Histology report (summary) * **Angiomyolipoma** growing out of the renal cortex, tumour cells were mildly pleomorphic, without mitosis or necrosis. MDM-2 negative. Additional small foci of angiomyolipomas in the kidney. * Case courtesy of Dr Igor Strahovnik, Radiopaedia.org, rID: 31532 * Contributor: Dr Mitja Četina

Answer 68

Aberrant papilla: * papilla indents infundibulum or pelvis rather than minor calyx * Figure 18-6 Frontal image of the left kidney from an intravenous urogram demonstrating an aberrant renal papilla in the lower pole infundibulum. https://radiologykey.com/kidneys-4/

Answer 69

Simple renal cyst Imaging Features * IVP * **Lucent defect** * **Cortical bulge** * Round indentations on collecting system * “Beak sign” can be seen with large cysts. * US * **Anechoic** * **Enhanced through-transmission** * Sharply marginated, smooth walls * Very thin septations may occasionally be seen. * CT * **Smooth cyst wall** * **Sharp demarcation** from surrounding renal parenchyma * **Water density (\<10–15 HU) that is homogeneous throughout lesion** * No significant enhancement after IV contrast administration (small increases of \<5 HU, however, can be seen likely due to technical factors, not true enhancement) * Cyst wall too thin to be seen by CT (with small cysts, volume-averaging may create the false appearance of a thick wall) * MRI * Indications (rather than CT): * renal insufficiency, * solitary kidney, * contrast allergy, * patients with complex cystic renal masses needing multiple follow-up examinations * End-expiration images are preferred because they are more reproducible in optimizing image coregistration and subtraction algorithms if the patient can hold his or her breath. * Simple renal cysts are **uniformly hypointense on T1W and hyperintense on T2W** images with no perceptible enhancement after gadolinium. MRI can characterize extremely small renal cysts. * Internal components of cystic masses and subtle enhancement are better appreciated by MRI than by CT Case courtesy of Dr Ian Bickle, Radiopaedia.org, rID: 83652

Answer 70

* Nephronophthisis * INHERITANCE * AR * GENES * More than 10 mutations identified to date (cili- opathy) * RENAL FINDINGS * Small hyperechoic kidneys; * loss of corticomedullary differ- entiation; * progressive cystic disease, * with numerous small discrete cysts located in the medulla and at the cortico- medullary junction; * common cause of chronic kidney disease in childhood * ASSOCIATED SYNDROMES * Asphyxiating thoracic dystrophy (Jeune syndrome); * Meckel-Gruber syndrome; * Joubert syndrome and related disorders; * Ellis–van Creveld syndrome; * short rib–polydactyly group

Answer 71

Sinus lipomatosis: * large amount of fat in renal sinus * It results from renal parenchymal atrophy, inflammation, calculous disease, ageing, or exogenous or endogenous steroids. * There is usually no or rarely little mass effect on the collecting system. * Variants * replacement lipomatosis of the kidney: an advanced massive form of renal sinus lipomatosis, in which infection, renal calculi, and long-standing hydronephrosis are accompanied by severe renal parenchymal atrophy; might be with mass effect causing attenuation and stretching of the collecting system Differential diagnosis * Possible differential considerations include: * xanthogranulomatous pyelonephritis: on ultrasound * fat-containing renal tumours * renal angiomyolipoma * renal lipoma * renal liposarcoma Case courtesy of Dr Khalid Alhusseiny, Radiopaedia.org, rID: 91277

Answer 72

* Lungs, 55% * Liver, 25% * Bone, 20% (classic lesions are lytic, expansile) * Adrenal, 20% * Contralateral kidney, 10% * Other organs, \<5%

Answer 73

Linear vascular impressions on renal pelvis and infundibula https://www.ajronline.org/doi/pdf/10.2214/ajr.101.3.719

Answer 74

Parapelvic Cyst * Originates from renal parenchyma but expands into the renal sinus * May cause compression of the collecting system * **Case Discussion** * The left kidney showed renal sinus cyst stretching and displacing pelvicalyceal system which is minimally dilated as compared to the right kidney. * A parapelvic cyst at times may cause compression of the pelvicalyceal system resulting in hydronephrosis. Parapelvic cyst can mimic hydronephrosis and so can be confused with pelvi-ureteric junction obstruction as the ureter in both conditions is not dilated. This could be well differentiated at the excretory phase of CT-IVP study (CT urography) that demonstrates stretched (but not dilated) collecting system by the cyst in contrary to PUJ obstruction at which the contrast will be excreted inside the dilated pelvicalyceal system. It can cause pelvicalyceal system dilatation by its mass effect. * Case courtesy of Dr Mostafa El-Feky, Radiopaedia.org, rID: 52815

GENITOURINARY IMAGING 2 Flashcards

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