genitourinary imaging

Question 1

87. imaging techniques of kidney and urinary tract diseases

Answer 1

o Conventional procedures:

1. Intravenous urography:
   - Used to be the most frequently performed investigation
   - Nowadays replaced by coronal CT/MRI section urography
2. Retrograde techniques:
   - Retrogradeurethrocystography
   - Retrograde cystography
   - Ureteropyelography
   - Associated with higher risk of infection and iatrogenic injury
3. Cystography:
   - Filling of the bladder with CM
   - Usually retrograde filling through bladder catheter
   Indications:
   - Test of reflux in children
   - Micturition cystourethrogram (antegrade visualization of the urethra in men) - Cystography: control cystourethral anastomoms after radical prostatectomy
4. Retrograde ureteropyelography:
   - Visulatisation of ureters and renal pelvis
   - Through catheter introduced into ureter
   - ATB protection
   - Not very common investigation
5. Ultrasound:
   - First investigation technique
   - Doppler is used to investigate renal arteries
6. CT:
   - Stones in the urinary tract (non-enhanced CT used)
   - Staging of tumors (always multiphase)
7. MRI:
   - In children
   - pregnant women
   - persons allergic to MC (it think, its supposed to say cm)

8. Angiography (DSA, CTA, MRA): 
DSA: 
- Gold standard for verification of suspected renal artery stenosis - Embolisation (A-V fistulas, tumor hemorrhage)  
CTA/MRA: 
- Verification of renal artery stenosis

Question 2

88. urolithiasis, obstructive urinary tract disorders

Answer 2

o Urolithiasis:
- Men are 2-4 times more commonly affected
- Causes: diet, composition of urine, infection, congestion
The composition of stones differ:
1. Calcium oxalate, calcium phosphate (85 %) – radiopaque
2. Uric acid stones (5-10%) – non-radiopaque
3. Struvite stones (trple phosphate) (5-10%) slightly radiopaque
4. Cystine stones (1%) – Slightly radiopaque
o Staghorn calculi:
- Usually seen in women after infection
- Treatment: lithotripsy with cystoscopic destruction (high-intensity focued US) o Bladder stones (rare):
- Caused by disruption of infravesical flow due to infravesical obstruction
- Symptoms: non/voiding difficulties
- Treatment: the same as staghorn calculi
o Radiological investigations of urolithiasis:
- Usually non-enhanced CT
- US
- Overview image of the urinary tract
- Use of IVU is declining
- Characteristic on US: hyperechoic structure with complete dorsal acoustic shadow

Question 3

89. benign kidney tumors

Answer 3

o Introducion:
Cystic lesions in the kidney:
1. Simple renal cycsts:
- Various in size, both kidney can be affected
- Ususally incidentally finding
- Complex cyst: cyst associated with hemorrhage or infection
- Cyst on US: sharp margin, anechoic/hypoechoic center, dorsal acoustic enhancement

2. Polycystic kidney disease:
   - Infantile aa type, Adult Aa/AA type, Medullary sponge kidney
   - 1st (dilated collecting tube and dilated bile ducts), 2nd (numerous cortical and medullary cysts in various sizes), 3rd (cystic changes in collection tube of pyramids + calcifications of pyramids
3. Von hippel-Linday disease:
   - Hemanioblastomas of the cerebellum, retina, renal-cell carcinoma, pheochromocytoma and numerous cysts in kidney, pancreas and liver
4. Acquired cystic kidney disease:
   - In patients with chronic renal failure

o Benign tumors:
- Majority small, asymptomatic and usually imaged incidentally by US/CT
1. Angiomyolipoma:
- Hamartous tumors composed of blood vessels, smooth muscles, connective tissue and fat Diagnosis:
US: round hyperechoid lesion
- Must be distinguished from renal-cell carcinoma
- Size > 4cm – indication for surgery (risk of bleeding)

2. Renal adenoma:
   - Rare beign tumors
   - Most common type oncocytoma (proximal tubule)
   - US, CT, MRI findings are unspecific

Question 4

90. malignant kidney tumors

Answer 4

o Renal-cell carcinoma (adenocarcinoma):

• Men
• Risk: von hippel-lindau syndrome, ACKD
• US or CT incidentially
• Stage imaging: CT/MRI (majority hypervascularized)
• Older: growth into VCI and causing thrombosis
  1. Ultrasound:
• Not sensitive or specific as CT or MRI
• Wide varying appearance (solid/partially cystic, hyper/iso/hypoechoic)
  2. CT:
• Small lesions enhance homogenously, whereas larger lesions have irregular enhancement due to areas of necrosis

o Urothelial tumors:
- Carcinoma of the renal pelvis
- Carcinoma of the ureter
- Carcinoma of the bladder (most common localization)
- Pelvic carcinomas are associated with bladder carcinomas
- Bladder cancer is examined by cystoscopy and cytological investigation
- For staging TU: CT/MRI urography
o Lymphoma
- Rare
- May occur in isolation or in numbers, one side or bilaterally
- Contrast enhanced CT
o Metastases:
- Primary tumor: lung, breast, GI tract, melanoma, leukemia, multiple myeloma

Question 5

91. inflammatory diseases of kidneys and urinary tract

Answer 5

ACUTE PYELONEPHRITIS 
CT
Sensitive modality 
Assess renal calculi, gas, perfusion defects, collections and obstruction 
Should be used sparingly – radiation 
Usually no need for urography 
Non-contrast CT 
Post-contrast CT 
Focal wedge-like regions will appear swollen 🡪 reduced enhancement 

CHRONIC PYELONEPHRITIS
Longstanding renal infection
Picture:
Upper: CT post contrast 🡪 Delayed contrast absorption of left kidney. Dilatetion of pelvis
Lower: CT post contrast 🡪 not very healthy kidneys

Recurrent infection:
MCU = Micturating cystourethrogram: 
rule out reflux disease
IVU = Intravenous urgraphy:
 rule out abnormalities. 
Cystitis
Acute: may have normal appearance
Chronic: thickened walls, diminished filling capacity. 
US: prostatitis, epididymitis

Question 6

92. diseases of prostate / testicles/ epidydimis/ retroperitoneum

Answer 6

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Question 7

93. imaging in obstetrics and gyn:
    - pregnancy
    - sterility

Answer 7

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Question 8

94. imaging in obstetrics and gyn
    - inflammatory changes
    - uterus
    - adnexal tumors

Answer 8

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