Radiology of Ureter and Urinary Bladder

Introduction

• Dr Syed Faizan Raza Jafri is an MBBS, MD specializing in medicine.

Radiology of Ureter and Urinary Bladder

• The ureters are paired tubes carrying urine from the renal pelvis to the bladder.
• They measure approximately 25-30cm in length.
• Anatomical landmarks and constrictions are clinically significant.

Imaging Features

Plain Radiography (KUB X-ray)

• The ureter is typically not visible unless calcifications/stones are present.
• Intravenous urography (IVU/IVP): contrast highlights the ureters.

Intravenous Urography (IVU)

• Outlines the ureters after contrast administration
• Demonstrates normal peristaltic contractions

Ultrasound

• Non-invasive, but limited for visualizing normal ureters unless dilated.
• Appears as tubular, anechoic structures with posterior acoustic enhancement.

CT

• Provides detailed cross-sectional imaging of the ureter.
• Identifies stones, strictures, and tumors.
• Three segments are identifiable:
  • Proximal: Renal pelvis to the sacroiliac joint
  • Middle: Sacroiliac joint to the pelvic brim
  • Distal: Pelvic brim to bladder insertion

MRI

• Rarely used for ureter imaging but provides excellent soft-tissue contrast.
• Helpful in identifying congenital anomalies or masses.

Key Constrictions of the Ureter

• Ureteropelvic junction (UPJ): Where the renal pelvis narrows into the ureter.
• Pelvic brim: Where the ureter crosses the iliac vessels.
• Ureterovesical junction (UVJ): Where the ureter enters the bladder wall.

Bladder

• A hollow, muscular organ located in the pelvis, primarily responsible for storing urine.

Imaging Features

Plain Radiography

• Only visible with contrast (e.g., cystography).
• Outlines bladder shape, detects filling defects (e.g. diverticula/ruptures)

Ultrasound

• Appears as an anechoic structure when filled with urine.
• Evaluates bladder wall thickness, and intraluminal masses/stones.
• Doppler can evaluate vascularization in tumors.

CT

• Excellent visualization of the bladder wall and surrounding structures.
• Helps delineate tumors and inflammatory conditions.
• Differentiates bladder tumors from surrounding tissues.

MRI

• Superior for soft-tissue contrast, useful for staging bladder cancer.
• Allows differentiation between tumors and surrounding tissues

Cystoscopy and Retrograde Cystography

• Invasive procedures.
• Allow direct visualization of the bladder.
• Retrograde cystography helps detect ruptures / fistulas with contrast.

Normal Anatomy on Imaging

Shape

• Pyramid-like in infants
• Ovoid in adults (when distended).

Wall Thickness

• Normally 3-5mm when distended.
• Thickening occurs in conditions like infection, inflammation or neoplasms.

Trigone Area

• Located between ureteric orifices and internal urethral opening
• Smooth compared to the rest of the bladder on imaging

Radiopathology of the Ureter and Urinary Bladder

Ureteric Obstruction

• Causes: Stones, strictures, tumors, or external compression.
• Imaging features: includes ultrasound (hydroureter and hydronephrosis - anechoic dilation of the renal pelvis/calyces) and echogenic shadowing of possible stones; CT (best for detecting ureteric stones, dilated ureter upstream from obstruction), strictures, and IVU/IVP (delayed contrast excretion, tapering at the site of obstruction),

Ureteric Stones

• Imaging Features:
  • KUB X-ray: Radio-opaque calculi (calcium, struvite) in the ureter's course
  • Radiolucent calculi (uric acid, cystine): require other imaging modalities like CT
  • CT (Non-contrast): Gold standard for stone detection (hyperdense focus with acoustic shadowing)

Ureteric Tumors

• Types: Urothelial carcinoma (most common), metastases
• Imaging Features include Irregular filling defects in contrast-filled lumen and wall thickening/irregular enhancement (CT); soft-tissue masses with hyperintense signal on T2-weighted images, and filling defects with delayed excretion (MRI and IVU, respectively)

Ureteric Trauma

• Imaging Features:
  • Extravasation of contrast from ureter, CT Urography
  • Associated Perirenal Hematoma/urinoma
  • Retrograde pyelography: precise location of the leak/disruption

Bladder Stones

• Imaging Features
  • KUB X-ray: Radiopaque stones in bladder (calcium-based)
  • Radiolucent stones require CT or ultrasound for evaluation
  • Ultrasound: Hyperechoic structures with posterior acoustic shadowing
  • CT: Clear visualization of stones, including radiolucent ones

Bladder Tumors

• Types: Urothelial carcinoma (most common), squamous cell carcinoma, adenocarcinoma
• Imaging features Include:
  • Ultrasound: hypoechoic or mixed echogenic masses projecting into lumen (with CT cystography showing irregular, enhancing masses)
  • MRI: Soft tissue masses with hyperintense signals in T2 weighted images, with irregular wall thickening and infiltration into adjacent fat

Bladder Trauma

• Types: Intra/extraperitoneal rupture
• Imaging Features:
  • Retrograde cystography
    • Contrast extravasation in intraperitoneal rupture; contrast only limited to perivesical spaces in extraperitoneal rupture; outlines bowel loops in intraperitoneal ruptures
  • CT cystography: preferred for trauma evaluations (clearly shows extravasation patterns)

Bladder Infections (Cystitis)

• Causes: Bacterial, tuberculosis, fungal
• Imaging Features
  • Ultrasound: thickened irregular bladder walls; echogenic debris in severe cases (emphysematous cystitis)
  • CT: wall thickening, stranding in perivesical fat
  • MRI: diffuse wall thickening, increased signal intensity on T2 weighted images

Bladder Diverticula

• Imaging Features
  • Ultrasound: Anechoic outpouchings from bladder
  • CT cystography: Contrast-filled diverticula; assess for stones / tumors within diverticula

Radiology of Benign Prostatic Hyperplasia (BPH)

• Non-cancerous prostate gland enlargement, often causing LUTS.
• Radiologic evaluation assesses prostate size, bladder effects, and complications (obstruction / infections).

Ultrasound (US)

• Transabdominal: Enlarged prostate ( >30 mL volumes); median lobe protrusion into bladder (intravesical protrusion); post-void residual volume to assess obstruction severity
• Transrectal (TRUS): more accurate measurement of prostate volume; hypoechoic or heterogeneous nodules in transition zone; detects complications (bladder wall thickening, stones)

MRI

• Best for detailed anatomy/staging, if needed.
• Features: Enlarged prostate predominantly in transition zone; T2-weighted images: heterogenous signal intensity due to nodules; compression of peripheral / central gland by hypertrophy

CT

• Rarely used specifically for BPH but may show enlarged prostate gland with bladder wall thickening/trabeculations, secondary findings like hydronephrosis from chronic obstruction
• Voiding Cystourethrography (VCUG): demonstrates bladder outlet obstruction (elongated, narrowed prostatic urethral, post-void residual urine)

Key Findings

• Enlarged prostate (>30g)
• Secondary changes in the bladder (wall thickening, trabeculations, diverticula, retained urine (postvoid residual
• Complications: bilateral hydronephrosis or hydroureter from chronic obstruction