Genitourinary System

GU LECTURE Kidney Ureter Bladder : KUB  KUB is variously called as plain film or scout film. It is done preliminary to IVP.  Difference in x-ray attenuation between the kidneys and the enveloping perirenal fat in plain films provides a crude index of renal anatomy and pathologic changes  Preliminary to IVP  Since IV contrast can hide the calculi (same xray density as contrast) it serves as the film of reference for all subsequent films done after injection of contrast material.

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Good to pick up calcifications. Observe for calcification over kidney, ureters, bladder regions and rest of the abdomen Can identify distended bladder Can identify abdominal and pelvic masses. Observe renal outline for size and mass density. Incidental non diagnostic findings on KUB may alert the physician to the possibility of urinary tract injury In trauma fracture of vertebrae, ribs or pelvis alerts you to GU tract injury. Psoas obliteration and concavity of spine towards the side of pathology. Abnormal air collections suggestive of renal or peri-renal abscess

Intravenous Pyelogram (IVP)  IVP is a radiological test that uses contrast to outline the kidneys, ureters and bladder.  Also known as intravenous urogram Utility  Useful for evaluating the anatomy of the kidneys, ureters and bladder  One can detect function when no contrast is excreted  absence of renal function .  absence of perfusion to a kidney  Useful to identify urinary tract obstruction  Useful to evaluate reno-vascular disease Common indications  Renal colic  Hematuria  Recurrent urinary tract Infections  Suspected reno-vascular hypertension Disadvantages  Labor and time intensive – it may take up to 6 hours to complete in the severe obstruction  It requires placement of an intravenous line.  Requires a bowel preparation for optimal results  Involves intravenous injection of potentially allergic and mildly nephrotoxic contrast  Nonionic contrast agents have lowered the incidence of adverse reactions.  IVP's are not useful in patients with renal dysfunction.  Newborns rarely have sufficient renal concentrating ability to allow the kidneys to be seen on an x-ray.

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Hydration is important May aggravate renal failure

Retrograde Pyelogram  Like IVP, retrograde pyelography relies on contrast medium to produce detailed X-ray images of the urinary tract. Utility  Defines ureters and collecting systems  While newer diagnostic techniques have replaced this test for many functions, retrograde pyelography may still yield better definition of the upper urinary tract, particularly the ureter and kidney collecting syst Indications  Commonly performed when IVP produces an inadequate picture. Useful to study urinary tract obstruction when further clarification of nature of ureteral obstruction is required  It also complements cystoscopy while investigating a patient with hematuria or recurrent or suspected cancer.  Detects small lesions in the collecting system E.g. Transitional cell carcinoma Limitations  Contrast complications  May aggravate an existing urinary tract infection or triggering one from the catheterization. Voiding cystourethrogram (VCUG)  Children with urinary tract infections.

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Reflux is detected if contrast is seen to flow in retrograde fashion up the ureters from the bladder. Pelvic trauma where rupture of the bladder or urethra is suspected.

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If the bladder is ruptured, extravasation of contrast will be seen outside the bladder in the pelvis or abdomen.  If urethra is ruptured, there is extravasation into the perineum  Patients with suspected bladder outlet obstruction  Obstructions or strictures or injury of the urethra can be seen on the x-rays taken during voiding. Limitations  Insertion of the catheter is painful.  While conventional voiding cystograms are still necessary to evaluate the male urethra for posterior valves and bladder trauma, the majority of reflux studies today are done effectively with radionuclide cystography. ULTRASOUND

2 The use of high-frequency sound waves to produce real-time images, provides a simple and painless way to examine the kidney, bladder, prostate and scrotum Advantages  Non-invasive test  Requires no preparation  No pain  Provides accurate anatomic information, including dimensions  No radiation risk  Avoiding the potential allergic and toxic complications of contrast media.  Can be used on individuals with poor kidney function in whom contrast cannot be given  No complications  Can be done at bedside  Relatively economical exam Utility  Helpful in defining renal, bladder and prostate anatomy 

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It is the test of choice to exclude Urinary tract obstruction  US can, in the majority of cases, diagnose hydronephrosis.  Good for evaluating Kidney size  Good to distinguish between cysts and solid mass.  Good to localize kidney for biopsy Common indications  Renal mass / Abdominal mass  Renal colic  Recurrent Urinary tract infections  Chronic renal failure  Acute glomerulonephritis  Hematuria Renal CT  CT scanning combines X-rays and computer to produce precisely detailed cross-sectional images of the genito urinary system.

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A CT scan is helpful in delineating the characteristics of anatomy and function of Kidneys Three-dimensional reconstructions of the kidney and blood supply provide "road maps" for planning surgeries.

INDICATION  Ultra fast CT is considered preferable to KUB for detection of suspected stones  If ultrasound evaluation is equivocal for a cyst, or is suggestive of malignancy  In evaluating solid abdominal masses  Hematuria  Local staging of cancer Kidney to allow definitive surgical management if needed  Renal artery and vein evaluation DISADVANTAGES  Requires placement of an intravenous line for IV contrast.  Exposes patient to radiation.  Contrast toxicity or allergy

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Most young children require sedation to undergo a CAT scan. CAT scans are relatively expensive

MRI MRI is as good as CT or better in characterizing lesions of kidney and prostate.  Because of its ability to show soft tissues in exquisite detail, MRI can detect disease and evaluate renal vasculature and inferior vena cava  MRI can delineate a cyst from a solid mass.  In can identify the spread of kidney cancer into the renal vein, inferior vena cava and perirenal area (Staging). Indication  When contrast CT cannot be done  MRI is useful to evaluate vascular lesions Disadvantages  Expensive  Limited availability  MRI has limited applicability for the urinary tract since the non-specificity of its signals makes it ineffective in detecting calcifications and bladder abnormalities.  Patients with pacemakers, aneurysm clips, ear implants and metallic pieces in vital body locations cannot be imaged safely 

ADRENALS Adrenal Adenoma  Incidence in the population is 2-8%  Diagnosis is often made as an incidental finding on CT examination.  In patient with no known primary, an adrenal mass is almost always a benign adenoma  In a patient with a known neoplasm, especially lung cancer, an adrenal mass is problematic and diagnosing a metastasis versus an adenoma is critical for prognosis CT findings  Size greater than 4 cm tend to be metastases or adrenal carcinoma  Heterogeneous appearance and irregular shape are malignant characteristics  Homogeneous and smooth are benign characteristics.  Intracellular lipid in adenoma results in low attenuation on CT  Little intracytoplasmic fat in metastases results in high attenuation on non-enhanced CT  Non-enhanced CT (NECT)  Threshold 10 HU  Sensitivity 79%, specificity 96%  Contrast-enhanced CT (CECT)  Because majority of CT examinations in oncology use IV contrast, the % washout is useful after 10 minutes.

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Adenomas have greater than 50% washout after 10 minutes Washout can also be used on adrenal masses that measure > 10 HU on NECT Alternative is to do MR or PET

3 Adrenocortical carcinoma  rare malignancy with a poor prognosis.  reported incidence: 2 cases per million persons.  tumors frequently are large, measuring 4-10 cm in cross-sectional diameter.  arise from the adrenal cortex  bilateral in up to 10% of patients.  Approximately 50-80% are functional tumors, with most causing Cushing syndrome. Endocrine syndromes associated with adrenocortical carcinoma  Cushing syndrome  Virilization and precocious puberty  Feminization  Primary hyperaldosteronism CT findings  Large mass (>4 cm)  Central necrosis or hemorrhage  Heterogeneous enhancement  Invasion into adjacent structures  Venous extension into the renal vein or inferior vena cava Adrenal metastases

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Unilateral adrenal mass or enlargement Small masses (<1 cm) - Adenoma, ganglioneuroma, hyperplasia, metastasis, and pheochromocytoma Large masses (>4 cm) - Carcinoma of adrenal cortex; cyst or pseudocyst; hematoma; infection; inflammation (eg, tuberculosis, histoplasmosis); metastasis (eg, lung or breast related); myelolipoma; neuroblastoma, ganglioneuroblastoma, or ganglioneuroma; pheochromocytoma (eg, multiple endocrine neoplasia)  Bilateral adrenal enlargement Common causes - Hemorrhage (eg, in infants, trauma, bleeding disorder), histoplasmosis, hyperplasia, metastasis (eg, lung or breast related), neuroblastoma, and tuberculosis Uncommon causes - Addison disease, adenomas, amyloidosis, carcinomas (eg, multiple, primary), infection (ie, others), lymphoma, pheochromocytoma (multiple endocrine neoplasia), and Wolman disease (eg, familial xanthomatosis) CT findings  appear as focal masses or distortion of the contour of the adrenal gland.  smaller than 3 cm may be homogeneous.  Larger lesions may have central necrosis or hemorrhage. These lesions are heterogeneous and may have thick enhancing rims. They may also invade contiguous organs such as the kidneys.  Attenuation values of less than 10 HU on unenhanced Pheochromocytomas  CT  large tumors (often >3 cm),

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they are usually round or oval masses with an attenuation similar to that of the liver Larger lesions frequently demonstrate necrosis, hemorrhage, and fluid-fluid levels. As a result, they often appear inhomogeneous. Calcification is rare, but it is reported

KIDNEYS Acute Pyelonephritis Etiology o Inflammation of the renal parenchyma and renal pelvis due to an infectious source o Most often secondary to an ascending lower urinary tract infection from gram-negative bacteria E. coli Klebsiella Proteus Pseudomonas. o Exception is S. aureus, which is spread hematogenously Pathologic Causes o Vesicoureteral reflux o Obstruction in the collecting system usually due to a calculus Complications o Abscess o Emphysematous pyelonephritis Most often occurs in diabetics Can produce gas in the collecting system and renal parenchyma. Radiographic Imaging Findings o Enlarged kidneys (U/S and CT) o Hydronephrosis (U/S and CT) o Wedge shaped areas of low attenuation secondary to decreased perfusion (CT) o Loss of the ability to distinguish the corticomedullary border (CT) o Perinephric stranding (CT) Emphysematous Pyelonephritis Acute, fulminant, necrotizing infection of kidney and perirenal tissues associated with gas formation which may be life-threatening • Organism o E. coli (vast majority of cases) o Klebsiella pneumoniae (9%) o Proteus mirabilis o Pseudomonas o Enterobacter o Candida o Clostridia (exceptionally rare) • Location o Most are unilateral o 5-7% bilateral • Types o Type I (33%) • Streaky or mottled gas in interstitium of renal parenchyma radiating from medulla to cortex

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4 Crescent of subcapsular or perinephric gas No fluid collection (= no effective immune response) Prognosis in this type is poor (69% mortality)

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• Type II (66%) • Bubbly and/or loculated intrarenal gas (infers presence of abscess) • Renal and/or perirenal fluid collection • Gas within collecting system in almost all CT findings o Most reliable and sensitive modality o Mottled areas of low attenuation extending radially along the pyramids o Extensive involvement of kidney and perinephric space o Air extending through Gerota’s fascia into retroperitoneal space o Occasionally gas in renal veins Ultrasound findings o High-amplitude echoes within renal sinus and/or renal parenchyma associated with "dirty" shadowing • "Comet tail" reverberations o Kidney may be completely obscured by large amount of gas in perinephric space (DDx: surrounding bowel gas) o Gas may be confused with renal calculi

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Renal Infarction • Thrombotic disease usually affects larger vessels o Includes main renal artery o Patients with thrombotic disease usually present with hypertension or renal insufficiency o Usually results from atherosclerosis  But, blunt abdominal trauma may cause intimal tears with subsequent dissection and thrombosis • Emboli can affect vessels of various sizes depending on the size of the emboli o Renal artery emboli usually come from cardiac source o Embolic disease usually produces acute symptoms  Sudden onset of flank pain  Hematuria  Proteinuria  Fever  Leukocytosis

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Trauma

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Blunt abdominal trauma

Traumatic avulsion of renal artery  Surgery Embolism  Cardiac origin • Rheumatic heart disease with arrhythmia o Atrial fibrillation • Myocardial infarction • Prosthetic valves • Myocardial trauma • Left atrial or mural thrombus • Myocardial tumors • Subacute bacterial endocarditis

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Catheters • Angiographic catheter manipulation • Umbilical artery catheter above level of renal arteries Arterial thrombosis  Arteriosclerosis  Thrombangitis obliterans  Polyarteritis nodosa  Syphilitic cardiovascular disease  Aneurysms of the aorta or renal artery  Sickle cell disease Sudden complete renal vein thrombosis

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Lobar Renal Infarction o Early signs  Focal attenuation of collecting system • Tissue swelling  Focally absent nephrogram • Triangular with base at cortex o Late signs  Normal or small kidney(s)  Focally atrophied parenchyma with normal interpapillary line  Cortical atrophy and irregular scarring are seen as late sequelae o CT  Subtle renal infarcts are best demonstrated on CT  Appear as wedge-shaped, cortically based, hypodense areas • Triangular in shape with widest part at the cortex (base of infarct)

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Non-perfused area corresponding to vascular division Renal swelling may also be seen Cortical rim sign • Entire kidney is nonenhancing except for the outer 24 mm of cortex, which are perfused by capsular branches

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US Focally increased echogenicity Color flow Doppler aids in diagnosis of renal artery thrombosis • There is absence of an intrarenal arterial signal • Tardus parvus waveform is seen if incomplete occlusion or collateral supply  Nuclear medicine • Nuclear imaging shows a photopenic area corresponding to the region of ischemia or infarction Chronic Renal Infarction o Pathology  All elements of kidney atrophied with replacement by interstitial fibrosis  Normal or small kidney with smooth contour  Globally atrophied parenchyma  Diminished or absent contrast material density o US  Increased echogenicity (by 17 days)

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Angiomyolipoma • Benign mesenchymal tumor of kidney • Rare • Histopathology o No true capsule o Commonly bleed o Tumor composed of fat, smooth muscle, aggregates of thick-walled blood vessels • Types o Isolated angiomyolipoma is most common (80%)  Usually solitary  Unilateral (80% on right side)  Not associated with tuberous sclerosis  Mean age of incidence: 40s

Much more common in females o Angiomyolipoma associated with tuberous sclerosis (in 20%)  Angiomyolipoma occurs in 80% of patients with tuberous sclerosis • Commonly large • Usually bilateral • Usually multiple  May be only evidence of tuberous sclerosis  Mean age of incidence: teens  Equal incidence in males and females Imaging findings o Mostly small lesions <5 cm in diameter o Many have a large exophytic component (25%) o Calcifications not common (6%) o Plain film findings  Mass of fat lucency is lesion is large enough o CT findings  Well-marginated, corticalbased, heterogeneous tumor predominantly of fat density (<-20 HU)  Variable enhancement (smooth muscle, vessels) US findings o Highly echogenic tumor due to high fat content o Less echogenic areas due to hemorrhage, necrosis, dilated calyces

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Kidney, Trauma Grading • Grade 1 o Hematuria with normal imaging studies o Contusions o Nonexpanding subcapsular hematomas • Grade 2 o Nonexpanding perinephric hematomas confined to the retroperitoneum o Superficial cortical lacerations less than 1 cm in depth without collecting system injury • Grade 3 - Renal lacerations greater than 1 cm in depth that do not involve the collecting system • Grade 4 o Renal lacerations extending through the kidney into the collecting system o Injuries involving the main renal artery or vein with contained hemorrhage o Segmental infarctions without associated lacerations o Expanding subcapsular hematomas compressing the kidney • Grade 5 o Shattered or devascularized kidney

Ureteropelvic avulsions Complete laceration or thrombus of the main renal artery or vein

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Nephrolithiasis/Urolithiasis • Passage of a urinary stone is the most common cause of acute ureteral obstruction KUB -Conventional radiography is often performed as a preliminary examination in patients with abdominal pain possibly resulting from urinary calculi

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Stones are often found at key points of narrowing such as the UPJ, the ureterovesical junction (UVJ), and the point at which the ureter crossing the iliac vessels. An addition site is on the right side where the ureter passes through the root of the mesentery. Calcium stones as small as 1-2 mm can be seen. Cystine stones as small as 3-4 mm may be depicted, but uric acid stones are usually not seen unless they have become calcified.

IVP - useful for confirming the exact location of a stone within the urinary tract. IVU depicts anatomic abnormalities such as dilated calyces, calyceal diverticula, duplication, UPJ obstruction, retrocaval ureter, and others that may predispose patients to stone formation or alter therapy - When a stone causes acute obstruction, an obstructive nephrogram may be present. This may be prolonged and hyperopaque, with increasing opacity over time. The nephrogram of acute obstruction is usually homogeneous, but may also be striated or occasionally not visible on radiographs. - Other signs include delayed excretion, dilatation to the point of obstruction, or blunting of the calyceal fornices. Immediately after the passage of a stone, residual mild obstruction or edema can be detected at the UVJ. Delayed images may be needed to opacify to the point of the obstruction, but using gravity to position the more opaque and more distal contrast material–laden-urine is also possible by placing the patient in a prone or erect position. CT SCAN -With a sensitivity of 94-97% and a specificity of 96100%, - helical CT is the most sensitive radiologic examination for the detection, localization, and characterization of urinary calcifications - CT scans frequently depict non-obstructing stones that are missed on IVU. - CT is faster and no contrast agent is needed in most patients. - CT easily differentiates between non-opaque stones and blood clots or tumors (compared with IVU, which may depict only a filling defect). - helical CT is better than US or IVU in detecting other causes of abdominal pain CT may depict the following: • Stones in the ureter • Enlarged kidneys

6 Hydronephrosis (83% sensitive, 94% specific) Perinephric fluid (82% sensitive, 93% specific) Ureteral dilatation (90% sensitive, 93% specific) Soft-tissue rim sign (good positive predictive value with a positive odds ratio of 31:1)

ULTRASOUND - on sonograms, stones are demonstrated as bright echogenic foci with posterior acoustic shadowing. - Stones are visualized fairly well with US in the kidneys and the distal ureter at or near the UVJ, especially if dilatation is present. - US is good for the visualization of complications such as hydronephrosis (or other signs of obstruction); however, some patients with acute obstruction have little or no dilation.

Acute obstructive uropathy - is a commonly encountered condition, occurring in both inpatient and outpatient settings. - The most common cause for acute obstructive uropathy is an impacted calculus. In 70% of patients, the level of obstruction is at the ureterovesical junction; in the remainder of patients, the ureteropelvic junction or mid ureter are the points where calculi tend to lodge. - Most calculi (90%) contain calcium, combined with oxalate and/or phosphate. - Magnesium ammonium phosphate (struvite) stones are the next most common type, and are observed most frequently laminated with calcium apatite. They form in the alkaline environment created by ureasesplitting bacteria, especially Proteus species, and commonly produce the staghorn appearance of the pelvocalyceal system. - Uric acid stones are less common, These stones, along with the less common xanthine and matrix calculi, appear radiolucent on plain radiographs. Cystine stones are less opaque than calcium stones and may be difficult to demonstrate on plain radiographs. IMAGING CT SCAN - Unenhanced helical CT has both a high sensitivity of 95-98% and a high specificity of 96-100% in detecting ureteral calculi in the acute setting. Both calcified and noncalcified calculi may be identified, along with the location and size of the stone. - Secondary signs of obstructive uropathy, including hydronephrosis, perinephric and periureteral stranding, as well as ureterectasis, are well demonstrated on CT. ULTRASOUND In the evaluation of acute flank pain, ultrasound (US) is limited primarily to pregnant patients. While US demonstrates renal calculi, it is poor at detecting ureteral stones The hallmark of obstruction on US is the presence of hydronephrosis. Prominent anechoic structures within

the renal sinus represent a dilated pelvocalyceal system. Renal calculi also may be demonstrated as echogenic foci with or without shadowing. This finding depends on the size of the calculi, with smaller stones blending into the echogenic renal sinus. Ureteral calculi and ureterectasis are detected less often. While UPJ and UVJ stones may be observed, mid ureteral stones are extremely difficult to detect. KUB The plain abdominal radiograph or KUB film has long been the initial imaging study of choice in patients presenting with symptoms of acute flank pain While 90% of stones contain calcium, the sensitivity of plain films has been reported at only 50-60%, with a specificity of 70%. Most noncalcified stones, blood clots, and most other intraluminal obstructive causes are radiolucent; therefore, they are not seen on abdominal radiographs. In trauma, the presence of pelvic fractures and soft tissue mass in the abdomen or pelvis may alert the radiologist to the possibility of ureteral injury, a rare complication, or obstruction from a large hematoma.

Renal Cell Carcinoma - the most common primary renal malignant neoplasm in the adult. - It accounts for approximately 85% of renal tumors and 2% of all adult malignancies. - RCC is more common in men than in women (ratio, 2:1), and - it most often occurs in patients aged 50-70 years. RCCs can be staged by using the American Joint Committee on Cancer TNM classification, as follows:

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Stage 1 RCCs are 7 cm or smaller and confined to the kidney. Stage 2 RCCs are larger than 7 cm but still organ confined. Stage 3 tumors extend into the renal vein or vena cava, involve the ipsilateral adrenal gland and/or perinephric fat, or have spread to one local lymph node. Stage 4 tumors extend beyond the Gerota fascia, to more than one local node or have distant metastases

Findings: Plain radiography Plain radiographic findings are often unrevealing in patients with RCC unless the mass contains detectable calcification or is large enough to distort the normal renal contour. Plain radiography has no role in the primary search for RCC or in the follow-up observation of patients with RCC because of its limited sensitivity and specificity.

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Intravenous urography Intravenous urography (IVU) is also limited in depicting RCCs. Large lesions, which can distort the renal contour or the collecting system, may be detected. Findings of RCC are nonspecific and include - mass effect on the collecting system, - distortion of the renal contour, - enlargement of a portion of the kidney, and - calcifications. - most RCCs are less attenuating than surrounding renal parenchyma. - Renal vein invasion may be inferred if contrast material excretion by the affected kidney is poor or absent. Alternatively, this finding may result from extensive involvement of the kidney or ureteral obstruction caused by mass effect. CT SCAN - On initial nonenhanced CT scans, RCCs may appear as isoattenuation, hypoattenuation, or hyperattenuation relative to the remainder of the kidney. Calcifications may be present and are usually amorphous and internal, although rimlike calcifications can also be present. - On contrast-enhanced CT scans, RCC is usually solid, and evidence of necrosis is often present. Sometimes RCC is a predominantly cystic mass, with thick septa and wall nodularity. RCC may also appear as a completely solid and highly enhancing mass. - Staging of RCC, which can be performed by using CT or MRI, includes the assessment of ipsilateral or contralateral adrenal involvement, direct extension into adjacent organs, enlargement of retroperitoneal lymph nodes, invasion of the ipsilateral renal vein (with or without extension into the inferior vena cava), and distant metastatic disease (liver, bone, lungs). Retrocrural, subcarinal, or mediastinal lymph nodes can also be enlarged.

ULTRASOUND: On sonograms, RCC can be isoechoic, hypoechoic, or hyperechoic relative to the remainder of the renal parenchyma. - Smaller lesions with less necrosis are more likely to be hyperechoic. - Isoechoic tumors are detected only by distortion of the renal contour, focal enlargement of a portion of the kidney, or distortion of the central sinus fat. - For the workup in RCC, US is used primarily to differentiate solid masses from simple cysts and to visualize the internal architecture of lesions more effectively than can be accomplished by using CT or MRI. URINARY BLADDER Bladder cystitis - is defined as inflammation of the urinary bladder from any cause. -female individuals, especially those younger than 50 years, are affected more often than male individuals -. The high incidence in women is due to the short length of the urethra and its proximity to the anus. ULTRASOUND: - The bladder appears sonographically normal in most cases but may show thickening of its wall due to edema.

- The bladder mucosa is normally less than 2 mm thick when measured at full distension and less than 5 mm thick when nondistended.

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