Planning percutaneous nephrolithotomy using multidetector computed tomography urography, multiplanar reconstruction...

Area of Science:

• Urology
• Radiology
• Medical Imaging

Background:

• Percutaneous nephrolithotomy (PCNL) requires precise anatomical mapping of the pelvicalyceal system (PCS) and renal calculi for optimal surgical planning.
• Complex renal calculi and challenging PCS anatomy can complicate PCNL access and increase risks.
• Accurate pre-procedural imaging is essential for selecting the best percutaneous entry point.

Purpose of the Study:

• To evaluate a modified multidetector computed tomographic urography (CTU) technique for accurate and reproducible mapping of the PCS and complex renal calculi.
• To determine if this CTU protocol aids in selecting the optimal percutaneous access route for PCNL.

Main Methods:

• A modified four-detector multislice CTU protocol was used in 10 patients with renal calculi.
• The protocol included frusemide administration, abdominal compression, and contrast injection during the pyelographic phase.
• Multiplanar reconstruction and 3D reformatting were employed for data analysis.

Main Results:

• The modified CTU successfully mapped the PCS and identified all renal calculi (staghorn, diverticular, calyceal, infundibular, and pelvic).
• Three-dimensional (3D) imaging subjectively improved the optimization of nephrostomy placement compared to conventional imaging.
• CTU accurately located stones in relation to the PCS, aiding in surgical planning.

Conclusions:

• The described CTU protocol with post-processing provides accurate and reproducible prediction of stone characteristics and optimal percutaneous access sites.
• This technique helps identify potential hazards during track placement without significantly increasing radiation exposure.
• 3D CTU is recommended as a standard imaging method for planning PCNL in selected patients with complex renal calculi.