GU Studies
Cystography (Retrograde Cystography)
Anatomy
Students should be able to identify the following structures on radiographic images:
Ureters, Bladder (Apex, Base, Neck, Trigone), Ureterovesical junction (UVJ), Urethra, Prostate (male)
Indications, Contraindications, and Patient Preparation
Indications
- Trauma (bladder rupture, laceration, or fistulae)
- Incontinence (inability to control urination)
- Urinary retention (incomplete emptying of bladder)
- Recurrent urinary tract infections
- Post-surgical evaluation (bladder repairs, ureteral reimplantation).
Contraindications
- Relative: Known sensitivity to iodinated contrast (rare).
- No absolute contraindications beyond contrast precautions.
Patient Preparation
- No special prep required
- Patient should empty bladder before catheterization
- Explain procedure, reassure patient.
Routine Projections (ARRT Required)
AP Axial (or PA Axial) Cystogram
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine for AP (preferred) or prone for PA. Arms at sides, legs extended.
- Adjustments: Align midsagittal plane to IR; ensure shoulders and hips equidistant. For AP, slight lordotic curvature or 15–20° Trendelenburg may improve visualization of distal ureters and ureterovesical junctions.
- CR: AP – 10–15° caudad, entering 2 inches (5 cm) above the pubic symphysis. PA – 10–15° cephalad, entering ~1 inch distal to the coccyx and exiting just above the pubic symphysis.
- Patient instructions: Suspend respiration at end of expiration.
- Exposure: 10 × 12 inch (24 × 30 cm) lengthwise collimation.
Evaluation Criteria
- Coverage (what anatomy must be included and how you verify it’s complete): Bladder, distal ureters, and proximal urethra visualized.
- Rotation checks (how symmetry or alignment tells you if positioning is correct): Symmetric pelvis and equidistant iliac wings.
- Motion checks (how sharpness confirms patient cooperation/exposure timing): Sharp bladder margins; no peristaltic blur.
- Technique checks (what contrast, density, soft tissue visibility, and artifacts to look for): Pubic bones projected below bladder neck and urethra; adequate contrast opacification.
- Clinical aim (when applicable, e.g., reflux, obstruction, displacement, etc.): Assess bladder contour, integrity, and reflux at the ureterovesical junctions.
AP Oblique (RPO / LPO) Cystogram
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine, rotated 40–60° into RPO or LPO.
- Adjustments: Flex knee of elevated side; abduct uppermost thigh to clear pubic region. Arm of elevated side across chest. Pubic arch on dependent side aligned with midline of grid.
- CR: Perpendicular, centered 2 inches above pubic symphysis and 2 inches medial to elevated ASIS. (For voiding studies: CR perpendicular at the pubic symphysis.)
- Patient instructions: Suspend respiration at end of expiration.
- Exposure: 10 × 12 inch (24 × 30 cm) lengthwise collimation.
Evaluation Criteria
- Coverage: Bladder, distal ureters, and proximal urethra demonstrated.
- Rotation checks: Open ureterovesical junction on elevated side; no thigh superimposition.
- Motion checks: Sharp visualization of contrast column.
- Technique checks: Pubic bones projected below bladder neck and urethra.
- Clinical aim: Demonstrate ureterovesical junctions and reflux pathways; during voiding, entire urethra visualized.
Lateral Cystogram
CR Location & Positioning
- SID: 40 inches
- Patient position: Lateral recumbent (right or left).
- Adjustments: Knees slightly flexed; MCP centered to midline of grid. Elbows flexed and arms raised to clear pelvis. Hips and femurs superimposed.
- CR: Perpendicular to IR, centered 2 inches above the pubic symphysis at the midcoronal plane.
- Patient instructions: Suspend respiration at end of expiration.
- Exposure: 10 × 12 inch (24 × 30 cm) lengthwise collimation.
Evaluation Criteria
- Coverage: Bladder in profile with anterior and posterior walls demonstrated.
- Rotation checks: Hips and femurs superimposed, pelvis true lateral.
- Motion checks: Clear margins; no patient movement.
- Technique checks: Proper density showing bladder base and distal ureters.
- Clinical aim: Evaluate fistulae between bladder and rectum, uterus, or vagina; assess wall defects or diverticula.
Hows & Whys of Cystography
Anatomy
- How is the trigone different from other bladder regions?
It remains fixed in position and does not expand during filling, making it an important landmark for ureteral and urethral openings. - How does prostate enlargement affect cystographic imaging?
It elevates the bladder base and creates a smooth filling defect along the bladder floor. - How do bladder diverticula appear radiographically?
As outpouchings or rounded projections of contrast beyond the normal bladder contour.
Positioning
- Why must the contrast bag not exceed 24 inches above the bladder?
To prevent excessive hydrostatic pressure that could overdistend or rupture the bladder. - Why is gravity filling used rather than manual injection?
It ensures gentle, controlled filling and avoids trauma to the bladder wall. - Why is the AP axial projection angled caudad?
The caudal angle projects the bladder neck and urethra below the pubic symphysis for unobstructed visualization. - Why are obliques performed?
They separate the ureterovesical junctions from the bony pelvis and demonstrate reflux or obstruction without superimposition. - Why is the lateral projection important?
It provides a profile view of the bladder walls, ideal for detecting fistulae, diverticula, or wall perforation.
Technique & Image Evaluation
- How do you verify adequate bladder filling?
Contrast should outline the entire bladder contour without evidence of rupture or overdistension. - How can you recognize patient rotation?
Unequal distances between the symphysis and acetabula or asymmetry of iliac wings indicate rotation. - How can you assess image sharpness?
Look for crisp bladder margins and visible trabecular pattern without motion blur. - How do you evaluate for leakage or perforation?
Contrast extravasation outside the bladder outline or into the peritoneal cavity indicates rupture. - How can vesicoureteral reflux be confirmed?
By observing contrast ascending from the bladder into the distal ureters during or after filling.
Clinical Applications
- Why is iodinated contrast used instead of barium?
Iodinated contrast is water-soluble and safely absorbed if bladder rupture occurs; barium would cause peritonitis if extravasated. - Why must the bladder be emptied before catheterization?
To avoid dilution of contrast and provide a consistent baseline volume for evaluation. - Why is cystography indicated after trauma?
It identifies ruptures, tears, or fistulae caused by pelvic injury. - Why is cystography helpful after bladder surgery?
It assesses anastomosis integrity, detects leaks, and confirms postoperative bladder capacity. - Why should gonadal shielding generally be avoided?
Shielding would obscure critical anatomy, particularly the bladder base and urethra.
