IVU 2

Ureteral Compression

• Ureteral compression is a device applied around the patient to create pressure on the distal ureters.

• Purpose: It helps contrast media pool at the renal pelvis for better imaging.

• The compression enhances visibility of renal structures during imaging.

Initial Examination Techniques

• Preliminary Examination: Involves performing a scout image called KUB (Kidneys, Ureters, Bladder).

  • Objective: To view the anatomy of the kidneys, ureters, and bladder.

• KUB Positioning: CR (Central Ray) is directed at the mid-sagittal plane, level of the iliac crest.

  • Note: An upright position checks for nephroptosis (kidney dropping).

Contrast Imaging

• Contrast fills kidneys, ureters, and bladder, enhancing visibility on images.

• Nephrograms: Images taken shortly after contrast administration (1-2 minutes).

  • Purpose: Displays enhanced kidney visualization to assess the renal pelvis and calyces.

• Post-Void Images: Indicates imaging taken after urinary evacuation.

  • Requires annotation to clarify timing.

Timing of Radiographic Imaging

• Timer starts after the completion of the contrast injection, not during.

• Mandatory to document the timing when films are taken after contrast administration.

• Typical protocols suggest timed imaging at intervals (e.g., 15 min, 30 min).

Patient Positioning for Imaging

• For optimal visualization:

  • Supine position with support for comfort.

  • Oblique imaging is commonly set at a 30-degree angle for better visualization of either kidney.

  • For right kidneys, the Left Posterior Oblique (LPO) position is recommended.

• True Lateral Imaging:

  • Requires a proper true lateral position with knees flexed and arms positioned out of the field.

Retrograde Urography

• This technique involves catheterization of the ureters and direct contrast injection into the renal collecting system.

• Indications: Used for patients with renal insufficiency or contrast sensitivity (e.g., to avoid contrast-induced nephropathy - CIN).

• Conducted under fluoroscopy in specialized settings (urology or surgery) rather than in standard radiology.

Cystography Overview

• Cystography examines the urinary bladder using retrograde contrast techniques.

• Conditions indicated for cystography include:

  • Vesicoureteral reflux, neurogenic bladders, bladder trauma, and stricture issues.

• Imaging generally involves the AP view, with CR positioned 2 inches above the pubic symphysis for bladder studies.

Evaluation and Criteria for Imaging

• Key features:

  • Proper positioning (e.g., ensuring no bony superimposition).

  • Markers must be placed appropriately on each image.

  • Patient comfort is essential during longer exams.

Male and Female Cystography

• Male Examination: AP oblique with specific angulation (35-40 degrees) for bladder neck visualization.

• Female Examination: Similar positioning but adjusted for anatomy and required projections.

• Key Difference: Ensure CR is adjusted depending on whether imaging the bladder (2 in above symphysis) or urethra (at symphysis).

Questions and Challenges in Imaging Procedures

• Students often face challenges with:

  • Remembering specific projections and patient positions.

  • Applying the correct CR angulation and understanding the anatomy visualized in images.

• Importance of practice and study aids like cheat sheets to reinforce learning and clarify doubts.