Indications, Contraindications, and Patient Preparation

Indications

• Vesicoureteral reflux (especially in pediatrics).
• Recurrent urinary tract infections.
• Evaluation of urethra during voiding (strictures, trauma, post-surgical assessment).
• Incontinence or abnormal voiding patterns.

Contraindications

• Relative: allergy to iodinated contrast.
• Active urinary tract infection (procedure may worsen infection).
• Severe urethral trauma (consult physician before catheterization).

Patient Preparation

• No dietary prep required.
• Patient should empty bladder before catheterization.
• Procedure explained carefully (especially to children and parents, since voiding during imaging can be stressful).
• Catheterization performed under aseptic technique.

Projections

AP (Female VCUG)

CR Location & Positioning

• SID: 40 inches
• Patient Position: Supine or semi-upright AP; legs slightly apart, arms at sides
• Adjustments: IR centered at the superior border of pubic symphysis
• CR: Perpendicular to IR, entering 2 in. above pubic symphysis (5° caudal angulation may be used to project pubic bones below bladder neck)
• Pt. Instructions: Remain still during filling; void when instructed. Suspend respiration at end expiration.
• Exposure: Routine urinary contrast technique

Evaluation Criteria

• Bladder, urethra, and reflux (if present) visualized
• Bladder neck and urethra unobscured by pubic bones
• Adequate contrast density throughout bladder and urethra

AP Oblique (Male VCUG – RPO)

CR Location & Positioning

• SID: 40 inches
• Patient Position: Supine, rotated into 30–40° RPO
• Adjustments: Penis placed obliquely against thigh to prevent superimposition; elevated thigh extended and abducted to avoid overlap
• CR: Perpendicular to IR, entering 2 in. above pubic symphysis and 2 in. medial to elevated ASIS
• Pt. Instructions: Remain still during filling; void when instructed. Suspend at end expiration.
• Exposure: Routine urinary contrast technique

Evaluation Criteria

• Entire urethra demonstrated, bladder neck unobstructed
• Urethra posterior to pubic rami, unobscured
• Reflux (if present) visualized

Lateral (Optional, Either Sex)

CR Location & Positioning

• SID: 40 inches
• Patient Position: True lateral, recumbent
• Adjustments: Knees flexed slightly for stability; arms flexed at right angle or elevated to clear pelvis; hips and femurs superimposed
• CR: Perpendicular to IR, centered 2 in. above pubic symphysis at midcoronal plane
• Pt. Instructions: Remain still during voiding, if feasible. Suspend at end expiration.
• Exposure: Routine urinary contrast technique

Evaluation Criteria

• Bladder and urethra in profile
• Hips and femurs superimposed
• May demonstrate fistulae or abnormal urethral course

Special Notes & Adaptations

• Metallic Bead Chain Technique (Female Stress Incontinence Studies):
  • Bead chain extends through urethra with proximal end in bladder and distal end taped to thigh
  • AP and lateral projections obtained upright at rest and during Valsalva maneuver
  • Used to evaluate posterior urethrovesical angle, urethral axis, and bladder floor mobility under stress
• Upright Voiding Studies:
  • Both men and women may be imaged upright to simulate normal voiding mechanics
  • Men: usually RPO position using a urinal
  • Women: typically AP upright; lateral may also be taken

Exposure Factors & Technical Considerations

• Contrast: Dilute iodinated contrast (150–500 mL for adults; less for pediatrics).
• Infusion technique: Fill bladder slowly by gravity only.
• Bag height: Contrast bag should not exceed 24 in. above bladder.
• kVp: 75–85.
• SID: 40 inches.
• Radiation protection: Gonadal shielding when possible (especially in pediatric studies, but without obscuring urethra).
• Dynamic fluoroscopy: Images captured during filling and especially during voiding phase.

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