Objectives

GU

• Renal mass

  • Describe the clinical setting and mode of presentation of  renal mass.

  • What are the common causes for renal masses?

  • What are the useful imaging modalities to investigate renal mass? Indicate when you would select each procedure.

    • Role of ultrasound for evaluation

    • Role of CT

    • Role of angiogram

    • Role of MR

  • Procedure sequence of choice / Diagnostic algorithm

  • Sensitivity, specificity, patient preparation and complications of procedures

  • What is the role of radiologist in biopsy of renal masses?

• Obstruction

  •  Describe the clinical setting and mode of presentation of  urinary obstruction.

  • What are the common causes for urinary obstruction?

  • What are the useful imaging modalities to investigate urinary tract obstruction? Indicate when you would select each procedure.

    • Role of ultrasound

    • Role of CT

    • Mechanism, indication and limitation of Renal scan

  • Procedure sequence of choice / Diagnostic algorithm

  • Sensitivity, specificity, patient preparation and complications of procedures

•  BPH

  • Describe the clinical setting and mode of presentation of  BPH

  • What are the useful imaging modalities to investigate BPH? Indicate when you would select each procedure.

    • Role of ultrasound

    • Role of CT

    • Procedure sequence of choice / Diagnostic algorithm

    • Sensitivity, specificity of procedures

  • Role of ultrasound for biopsy

• Testicular mass

  • Describe the clinical setting and mode of presentation of  testicular mass

  • What are the common conditions presenting as testicular mass?

  • What are the useful imaging modalities to investigate testicular mass? Indicate when you would select each procedure.

• Hematuria and flank pain

  • Describe the clinical setting and mode of presentation of  renal stones

  • What are the radiological findings of renal stones in four views abdomen

  • What are the useful imaging modalities to investigate renal stones? Indicate when you would select each procedure.

  • Utility of imaging procedures

  • Procedure sequence of choice / Diagnostic algorithm

  • Sensitivity, specificity, patient preparation and complications of procedures

• Chronic renal failure
  • Objectives and role of imaging procedures
• Acute Glomerulonephritis
  • Objectives and role of imaging procedures

• Trauma

  • Kidney laceration

  • Bladder rupture

  • Urethral rupture

• Urinary tract infections

What are the common clinical conditions requiring imaging procedures in Genitourinary diseases?

• Renal masses
• Flank pain and hematuria
• Urinary tract obstruction
• Benign prostatic hypertrophy
• Cancer prostate
• Testicular masses
• Testicular torsion
• Chronic renal failure
• Acute Glomerulonephritis
• Trauma

What are the Imaging procedures useful in evaluation of Genitourinary diseases

• Flat plate abdomen
• IVP
• Retrograde pyelogram
• Ultrasound
• CT
• MRI
• Angiogram
• Renal scan

What is the utility of flat plate abdomen in Genitourinary diseases?

• Good to pick up radio opaque stones and calcification of kidney
• Poor sensitivity for ureteral stones
• Can identify distended bladder

What is the utility of IVP in Genitourinary diseases?

• Useful for evaluating the anatomy of the kidneys and in detecting any underlying anatomic abnormalities predisposing to stone formation or which could affect stone therapy.
• Used to identify obstruction associated with stone disease, both acute and chronic obstruction.
• Good visualization of kidney, ureters and bladder
• Depends on excretory capacity of kidneys
• Disadvantages
  • Labor and time intensive – it may take up to 6 hours to complete in the severe obstruction
  • Requires a bowel preparation for optimal results
  • Involves intravenous injection of potentially allergic and mildly nephrotoxic contrast
  • Hydration is important

What is the utility of retrograde pyelogram in Genitourinary diseases?

• To visualize bladder, ureters and calyx
• useful to study urinary tract obstruction

What is the utility of ultrasound in Genitourinary diseases? 

• It is the test of choice to exclude UTO
• US can, in the majority of cases, diagnose hydronephrosis and establish its cause.   
• Simple procedure with no complications and no radiation risk
• avoiding the potential allergic and toxic complications of contrast media.  
• Can be done at bedside
• Good for evaluating Kidney size and calyx
• Good to distinguish between cysts and malignancy.  

What is the utility of CT in Genitourinary diseases?

• A renal CT scan both with and without IV contrast is useful if ultrasound evaluation is equivocal, or is suggestive of malignancy,
• CT is as accurate as, and obviates the potential morbidity of, angiography in defining the renal mass.  
• Also, CT can give information about local staging to allow definitive surgical management if needed

What is the utility of MRI in Genitourinary diseases?

• Good to evaluate renal vasculature and inferior vena cava
• MRI is used to evaluate solid contrast enhancing vascular tumors seen on CT if a caval thrombus is suspected.   

What is the utility of renal scan in Genitourinary diseases?

• The renal scan is used when radiological examination demonstrates hydronephrosis without evidence of obstruction. 
• Megaureter due to previous marked vesicoureteral reflux or dilated but nonobstructed extra renal pelvis are the most common examples.  
• These patients are often being evaluated for back or flank pain, and the scan is used to evaluate if there is obstruction and if the obstruction is causing pain.  
• The scan involves the administration of a loop diuretic prior to a radio nuclide renal scan with percutaneous insertion of a catheter into the dilated renal pelvis.  
• The increase in urine flow should, if obstruction is present, slow the rate of washout of the radioisotope during the renal scan.  
• The procedure may precipitate similar pain as initial complaints.     

What is the utility of angiogram in Genitourinary diseases? 

• For evaluation of renal artery stenosis
• For delineation of vascular tumors
• If the CT scan is indeterminate

RENAL MASS   

• Simple renal cysts
• Malignancy
• Polycystic kidney disease
• Abscess

What are the useful imaging modalities used to investigate a renal mass and their utility?

• Ultrasonography- 
  • The initial diagnostic choice
  • US can distinguish between cysts and malignancy.  
  • Three major criteria for a single simple cyst on ultrasound are:  
    • the mass is round 
    • sharply demarcated with smooth walls
    • no echoes (anechoic) within mass; strong posterior wall echo indicating transmission through the cyst.  
  • No further evaluation is necessary if all of these criteria are satisfied, since the likelihood of malignancy is small.  
  • suggestive findings of malignancy 
    • mass is solid 
    • complex
    • with internal echoes and irregular walls
  • If US equivocal, or suggestive of malignancy, then proceed to CT.   
• CT
  • CT should be performed if initial ultrasound is equivocal, if calcifications or septae are seen, or if multiple cysts are clustered so that they may be masking underlying carcinoma. 
  • A renal CT scan both with and without IV contrast is the next appropriate step. 
  • It had replaced the renal arteriography as the next diagnostic step. 
  • CT is as accurate as, and obviates the potential morbidity of, angiography in defining the renal mass.  
  • Also, CT can give information about local staging to allow definitive surgical management if needed.
• Angiogram
  • If the CT scan is indeterminate, for example the mass is complex without contrast enhancement, then proceed to renal arteriogram to further define the diagnosis.   
• MRI
  • MRI is used to evaluate solid contrast enhancing vascular tumors seen on CT if a caval thrombus is suspected.   

How do simple renal cysts present?

• These cysts are typically asymptomatic.  
• Most of them are detected as incidental finding with other studies.
• Most common in patients over 50 years of age.  

How do you investigate suspected case of simple renal cyst?

• Ultrasound is the imaging procedure of choice
• Three major criteria for a single simple cyst on ultrasound are 
  • the mass is round and sharply demarcated with smooth walls
  • no echoes (anechoic) within mass
  • strong posterior wall echo indicating transmission through the cyst
• No further evaluation is necessary if all of these criteria are satisfied, since the likelihood of malignancy is small.   

• Patients either present for screening because of a positive family history or for evaluation of symptoms.  
• Acute abdominal flank pain, back pain, and hematuria are the most common clinical manifestations.  
• Clinical manifestations of ADPKD rarely occur before the age of 20-25. 
• Autosomal dominant PKD is the most common hereditary renal disease in the US and affects more than 500,000 people. 
• Often associated with ADPKD1 gene (the most common cause of autosomal dominant polycystic kidney disease.)  

How do you investigate suspected patients having polycystic kidney?

• Radiological evaluation is usually done by ultrasound. 
• A positive test requires: 
  • in patients younger than 30 years of age, 
    • at least two cysts (unilateral or bilateral)
  • in patients 30-59 
    • at least two cysts in each kidney
  • in patients over 60
    • one or more cysts

When will you suspect renal or peri-renal abscess?

• Often presents with 
  • flank pain
  • febrile urinary tract infection 
  • a renal mass on ultrasound

Describe the clinical setting and mode of presentation of cancer Kidney

• Renal cell has an increased predilection for men with a ratio of male-to-female of about 2:1.  
• Incidence of malignancy peaks at years 50-70.  
• The classic clinical manifestation of renal cell carcinoma is a triad of hematuria, flank pain and palpable flank mass.  
• However, the entire triad is seen only in 10% of patients, but at least one of these symptoms is present in more than half of patients as an initial manifestation of the tumor.  
• Fever is present in 20% of cases, elevated ESR in 50%.  
• Anemia is present in one third of patients and polycythemia secondary to increased erythropoietin production by the mass may be present.   

•   CT should be performed if initial ultrasound is equivocal, if calcifications or septae are seen, or if multiple cysts are clustered so that they may be masking underlying carcinoma. 
•   CT scans findings suggestive of malignancy 
  • Cysts with thickened or irregular walls
  • Thickened or enhanced septae within the mass
  • Enhancement of the lesion after contrast administration
  • A multilocular mass

What is the sequence of imaging procedures for renal masses?

• Renal mass on IVP

  • Renal Ultrasound

    • CYSTIC (smooth walls, no internal echoes)  OBSERVE

    • SOLID/COMPLEX (internal echoes, irregular walls) CT Scan 

      • SOLID (contrast enhancement, vascular tumor) Surgery 

      • SOLID (contrast enhancement, vascular tumor) Suspected caval thrombus  MRI  Surgery 

      • COMPLEX MASS (no contrast enhancement, indeterminate)  Renal Arteriogram   

        • Neovascularity  Surgery  

        • Avascular FNAB  Malignant cells  Surgery   

How would you confirm the nature of renal mass ? 

• Fine needle aspiration has limited value in the evaluation of a renal mass. 
• Fine needle aspiration biopsy can be performed with ultrasound guidance. 

What is the sensitivity, specificity and complications of fine needle aspiration biopsy (FNAB)

• The sensitivity and specificity of FNAB for a renal cell carcinoma is 80-95%.  
  • Therefore, 5-15% of renal cell carcinomas are missed in FNAB. 
• FNAB is also useful in the diagnosis of abscess or cancers such as lymphomas.
• Complications include 
  • bleeding, infection
  • needle tract seeding
  • arteriovenous fistula
  • pneumothorax.   

What is the role of imaging procedure in therapy of renal or peri-renal abscess?

• Ultrasound guided FNAB 
  • is useful for the diagnosis of abscess 
  • and for  concomitant drainage tube placement

Urinary tract obstruction   

• Congenital urinary tract malformation 
  • Meatal stenosis  
  • Ureterocele  
  • posterior urethral valves   
• Intraluminal obstruction  
  • Calculi  
  • Blood clots  
  • Sloughed papillary tissue  
• Extrinsic compression  
  • Pelvic tumors  
  • Prostatic hypertrophy  
  • Retro peritoneal fibrosis   
• Acquired anomalies  
  • Urethral strictures  
  • Neurogenic bladder  
  • Intratubular precipitates   

Describe the clinical setting and mode of presentation of urinary obstruction

• The clinical manifestations of UTO vary with the site, degree and rapidity of the obstruction.  
• A change in urinary habits is often the presenting sign of urinary tract obstruction.  
  • Complete obstruction is the most common cause of true anuria, and is an important cause of end stage renal failure.  
  • However, polyuria, especially nocturia, is not uncommon in partial obstruction and may occur as a consequence of defective urinary concentration. 
• Azotemia or renal failure occurs only if the drainage of both kidneys is significantly compromised.  
• Pain is often present secondary to bladder, collecting system or renal capsular distention.  
  • Pain is usually seen in acute obstruction, and is rare in partial or slowly progressive obstruction.  
• Hypertension is occasionally induced by UTO.  
  • The mechanism responsible for the blood pressure elevation is dependent upon duration and type of obstruction.  
  • Acute, unilateral obstruction causes HTN via activation of renin-angiotensin system; the increase in renin secretion is lateralized to the obstructed kidney (similar to unilateral renal artery stenosis.)  
  • In patients with bilateral UTO, HTN is secondary to volume expansion and resolves with diuresis.  
  • The plasma renin activity is also typically normal in chronic unilateral obstruction and the presence of the contra lateral normal kidney prevents both renal failure and the fluid retention. 
  • Furthermore, relief of the obstruction may not correct the HTN.   

What are the useful imaging modalities to investigate urinary tract obstruction?

• Renal ultrasound
  • It is the test of choice to exclude UTO, avoiding the potential allergic and toxic complications of contrast media.  
  • US can, in the majority of cases, diagnose hydronephrosis and establish its cause.   
• CT
  • CT should be used 
    • if the ultrasound results are equivocal 
    • the kidneys cannot be well visualized
    • if the cause of the obstruction cannot be identified.   
• Renal scan
  • The renal scan is used when radiological examination demonstrates hydronephrosis without evidence of obstruction. 
  • Megaureter due to previous marked vesicoureteral reflux or dilated but nonobstructed extra renal pelvis are the most common examples.  
  • These patients are often being evaluated for back or flank pain, and the scan is used to evaluate if there is obstruction and if the obstruction is causing pain.  
  • The scan involves the administration of a loop diuretic prior to a radio nuclide renal scan with percutaneous insertion of a catheter into the dilated renal pelvis.  
  • The increase in urine flow should, if obstruction is present, slow the rate of washout of the radioisotope during the renal scan.  
  • The procedure may precipitate similar pain as initial complaints.   

• Ultrasonography is the first choice in imaging. 
• If the US is equivocal, the kidneys cannot be well visualized, or if the cause of the obstruction cannot be identified, then the next imaging modality used should be CT.  
• Finally, a renal scan may be used if previous imaging (US or CT) demonstrates hydronephrosis without evidence of obstruction. 

• Renal ultrasound is a good initial diagnostic tool for urinary tract obstruction, however US can both under diagnose hydronephrosis (high false negative rate) and over diagnose obstruction secondary to appearance of hydronephrosis (high false positive rate).      

What is the role of retrograde pyelogram in evaluating patients with urinary tract obstruction?

Hematuria and Flank Pain  

• Nephrolithiasis is a common disease affecting men more frequently than women, with a ratio of 3-4:1.  
• Initial presentation is in the third to fourth decade.  
• The overall prevalence of urinary tract stone disease is 2-3% of the population per year.  
• The likelihood that a white male will develop stone disease by the age of 70 years is 1 in 8.
• There are five major types of urinary stones: calcium oxalate, calcium phosphate, struvite, uric acid and cystine.
• Several factors contribute to the development of stones.  
• Stone formation requires saturated urine that is dependent upon pH, ionic strength, solute concentration, and complexation. 
• Geographic factors contribute to the development, including areas of high humidity and elevated temperatures.  
• Diet and fluid intake may contribute to the development of stones, especially dehydration and excess sodium intake.   
• Certain medications (including acetazolamide, allopurinol, chemotherapeutic agents, calcium carbonate, methoxyflurane, loop diuretics, vitamin D) can predispose an individual to renal stones. 
• Genetic factors may also contribute to stone formation. 
• Cystinuria is an autosomal recessive disorder and individuals who are homozygous have increased excretion of cystine and frequently numerous recurrent episodes of urinary stones.  
• In addition, distal renal tubular acidosis may be transmitted in a hereditary trait, and urolithiasis is very common in these individuals.
• Obstructing urinary stones usually present with pain occurring suddenly and may awaken patients from sleep.  
• This severe colic pain is often localized to the flank and may be associated with nausea and vomiting.  
• Patients are constantly moving, unable to find a comfortable position.  
• The pain may occur episodically and may radiate anteriorly over the abdomen.  As the stone moves down the ureter, the pain may be referred to the ipsilateral testis or labium.  
• If the stone becomes lodged at the ureterovesical junction, urinary urgency and frequency will be a complaint.

What are the radiological findings of renal stones in four views abdomen?

• Ninety percent or more of urinary-tract stones are radio-opaque.  
  • The degree of opacity varies depending upon the composition.  
  • The greatest degree of opacity are seen the stones that are pure calcium phosphate(6%), pure calcium oxalate (33%), or calcium combinations of oxalate and calcium phosphate (34%).  
  • Struvite, magnesium ammonium phosphate, stones (9-15%), are also opaque, but to a lesser degree but are often easily visible as they tend to be large branched or stag horn stones. 
  • Cystine stones (1-3%) have a very low degree of opacity and except in a well-prepared patient with a very large stone, are invisible on the routine abdominal film.  Uric acid stones (8%) are radio lucent.
• Pure or nearly pure stones of a single composition may have characteristics enabling their identification on routine abdominal films. 
  • Calcium oxalate dihydrate stones – less dense and have “mulberry” or cotton ball-like configurations
  • Calcium phosphate stones – most dense and have “hard” appearance
  • Struvite stones – less dense and represent typical branched stag horn calculus
  • Cystine stones – even less dense than struvite or calcium stones and may have “ground glass” appearance
• Identification of the composition of a stone from a radiograph is not accurate.  
• Determination of stone composition accurately requires chemical stone analysis.
• Visibility of stones depends not only on the degree of opacity, but also on their sizes and positions relative to other abdominal structures.  
• An opaque stone needs to be approximately 2mm in its largest diameter to be visible on an abdominal film.

What are the useful imaging modalities to investigate renal stones? Indicate when you would select each procedure.  Utility of imaging procedures.

• Abdominal radiograph of the kidneys, ureter, and bladder (KUB)
  • Allows for the evaluation of urinary tract stones
  • Poor sensitivity for ureteral stones
• Excretory Urogram - also known as intravenous urogram (IVU) and intravenous pyelogram (IVP)
  • Not used for specific identification of stones
  • Useful for evaluating the anatomy of the kidneys and in detecting any underlying anatomic abnormalities predisposing to stone formation or which could affect stone therapy.
  • Used to identify obstruction associated with stone disease, both acute and chronic obstruction.
  • Labor and time intensive – it may take up to 6 hours to complete in the severe obstruction, requires a bowel preparation for optimal results, and involves intravenous injection of potentially allergic and mildly nephrotoxic contrast
• Ultrasound
  • Not dependent on the composition of stones and detects uric-acid stones as well as calcium stones.
  • Stones are seen as highly echogenic foci and often produce distal acoustic shadowing
  • Not always possible to distinguish small stones from arterial calcifications, pericalceal fat, or crystal-laden calceal submucosal plaques.
  • Detects hydronephrosis
  • Generally good sensitivity
• Non-contrast helical computed tomography of the abdomen (NCHCT)
  • Greater sensitivity than KUB for ureteral stones
  • Most sensitive and specific (95-97% and 96-97% respectively)
  • Because abdomen and pelvis are scanned in one to two breaths, virtually eliminates the problem of respiratory motion
  • Can be performed quickly, eliminating potential delays
  • Safe, because eliminates the risk of contrast, which includes allergic reactions and toxicity
  • Detects non-urologic pathology – including appendicitis or ovarian cysts
  • While more expensive than a KUB, comparable to a excretory urography and ultrasound
  • Able to detect all stones regardless of composition, except those associated with indinavir therapy for HIV infection

Procedure sequence of choice / Diagnostic algorithm.  

• Controversy exists over the proper procedure sequence.  
• With the addition of non-contrast helical CTs, some researchers advocate CT as the first-line procedure.  
• However, most physicians continue to utilize plain radiographs of the abdomen (KUB) as the mainstay of radiology procedures. 
• Here is one suggestion of a diagnostic algorithm. 

1)      History & Physical Exam – renal colic, flank pain, infection, or hematuria

2)      KUB (can utilize CT in place of KUB, especially if suspect other nonurologic pathology)

3)      If needed, CT or ultrasound

4)      Intravenous urogram – “delayed nephrogram” is one of the hallmark signs for acute urinary obstruction

5)      Medical Management

6)      If needed, extra corporeal shock wave lithotripsy

7)      If needed, (especially infected or large stones) percutaneous nephrolithotomy or open surgery 

• All radiological procedures sensitivity and specificity are dependent on the quality of the images and the skill of the interpreter.

BPH 

• Slowly progressive difficulties with bladder emptying and filling are characteristic of BPH.  
• Bladder emptying symptoms include straining, hesitancy, intermittency, a weak stream, terminal dribbling, and a sensation of incomplete emptying.  
• Bladder filling symptoms include daytime frequency, nocturia, urgency, and urge incontinence. 

• Ultrasound- Imaging is used only in cases where urinary tract obstruction is suspected, or in patients with microscopic hematuria or elevated creatinine levels.   
• CT- CT may be used in cases where carcinoma is suspected and local nodal involvement needs to be assessed. 

What is the sequence of imaging procedures that should be undertaken in patients with BPH?

• Routine laboratory tests performed on men with lower urinary tract symptoms generally include a urinalysis to rule out infection and to look for microscopic hematuria, which may indicate genitourinary malignancy and a serum creatinine measurement which, if elevated, may indicate obstructive uropathy.  
  • The role of prostate specific antigen testing is controversial. 
  •   Prostate screening studies do not confirm that patients with lower urinary tract symptoms suggestive of BPH are more likely to harbor prostate cancer.  
• If obstruction is a concern, the imaging modality of choice is ultrasound.  
• If neoplasia is suspected, and prostatic biopsy is performed, a CT may be obtained to assess nodal involvement.   

Cancer Prostate

Describe the clinical setting and mode of presentation of Cancer Prostate.

What are the useful imaging modalities to investigate Cancer Prostate?

• Ultrasound
• CT
• Bone scan

What is the role of ultrasound in the evaluation of cancer prostate?

• If obstruction is a concern, the imaging modality of choice is ultrasound.  

What is the role of CT the evaluation of cancer prostate?

• If neoplasia is suspected, and prostatic biopsy is performed, a CT may be obtained to assess nodal involvement.   

What is the role of bone scan in the evaluation of cancer prostate?

• Bone scan is useful to detect bony metastases

What is the sequence of imaging procedures that should be undertaken in patients with Cancer Prostate.

What is the role of ultrasound, for biopsy of prostate in diagnosing cancer prostate?

• Transrectal ultrasound can be used to localize and biopsy a suspicious area.  
• This method is better than blind biopsy. 
• However, because this is limited to hypo echoic lesions or palpable masses, many malignancies may be missed and therefore the sextant method is used more frequently.    

Testicular Mass   

What are the common conditions presenting as a testicular mass?

Differential Diagnosis of testicular mass (in adults and children)

• Testicular torsion
• Testicular cancer  
• Hydrocele
• Epididymitis
• Varicocele
• Spermatocele
• Inguinal hernia

What are the objectives in use of imaging procedures to evaluate renal failure?

What are the common causes for acute renal failure?

What imaging procedures are considered in a  patient with acute renal failure?

What are the common causes for chronic renal failure?

What imaging procedures are considered in a patient with acute renal failure?

What is the role of imaging procedure in a patient with acute glomerulonephritis?