Eur Radiol (2009) 19: 1280–1288 DOI 10.1007/s00330-008-1261-x
Uday Patel Richard Miles Walkden Khurshid R. Ghani Ken Anson
Received: 30 July 2008 Revised: 13 October 2008 Accepted: 14 November 2008 Published online: 14 January 2009 # European Society of Radiology 2009 U. Patel (*) . R. M. Walkden Department of Radiology, St George’s Hospital and Medical School, Blackshaw Road, London, SW17 0QT, UK e-mail:
[email protected] Tel.: +44-208-7253667 Fax: +44-208-7252936 K. R. Ghani . K. Anson Department of Urology, St George’s Hospital and Medical School, Blackshaw Road, London, UK U. Patel . K. Anson Princess Grace Hospital, Nottingham Place, London, UK
UROGENI TAL
Three-dimensional CT pyelography for planning of percutaneous nephrostolithotomy: accuracy of stone measurement, stone depiction and pelvicalyceal reconstruction
Abstract Retrospective evaluation of computed tomographic (CT) pyelography before percutaneous nephrostolithotomy (PCNL). Twenty patients with renal calculi underwent CT pyelography using a dedicated protocol. Calculus size, uniformity of contrast excretion and accuracy of calculus and pelvicalyceal (PC) system reconstructions were scored and compared on axial and coronal maximum intensity projections (MIP) and volume reconstructions (VRmovie loops). After contrast medium administration, the size of calculi is accurate on axial images, but underestimated on coronal studies: mean 14.7 mm vs. 14.4 mm (axial) and 17.2 mm vs. 16.1 mm (coronal) for measurements before and after enhancement, respectively (p=0.11 and 0.03). Uniform contrast medium excretion (median 228 HU;
Introduction The management of renal calculi is principally determined by presenting symptoms and calculus size, but is facilitated by accurate knowledge of calculus location, how the calculus branches and its spatial relationship within the collecting system [1, 2]. Calculi in dependent calyces with narrow infundibula are less likely to drain after extracorporeal lithotripsy [1], and renal access for percutaneous nephrostolithotomy (PCNL) has to be chosen after careful analysis of the pelvicalyceal (PC) anatomy [2]. A wellselected track will aid nephroscopic navigation and calculus retrieval. Traditionally, PC anatomy has been determined from an intravenous urogram (IVU) or retrograde pyelogram
95% CI 209–266 HU) was sufficiently lower than calculus density (median 845 HU; 95% CI 457-1,193 HU) for precise calculus and pelvicalyceal reconstructions in 87% and 85%, respectively. Coronal MIP scans were rated best for calculus depiction (mean score 2.68 vs. 2.50 and 2.41 for coronal, axial and VRs, respectively; p=0.14) and VR studies best for PC anatomy (mean score 4.4 vs. 3.73 and 2.89 for VR, coronal and axial studies, respectively; p=
