Andreas Helck MD, Presenter: Nothing to Disclose

Fabian Bamberg MD, Abstract Co-Author: Nothing to Disclose

Wieland H. Sommer MD, Abstract Co-Author: Nothing to Disclose

Christoph R. Becker, Abstract Co-Author: Nothing to Disclose

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Konstantin Nikolaou MD, Abstract Co-Author: Nothing to Disclose

Dirk-Andre Clevert MD, Abstract Co-Author: Nothing to Disclose

Mike Notohamiprodjo, Abstract Co-Author: Nothing to Disclose

Matthias Wessely MD, Abstract Co-Author: Nothing to Disclose

To evaluate amount of contrast administration and radiation exposure in an optimized multiphasic renal CTA protocol in a consecutive set of patients with history of renal transplantation.

The patients received a time-resolved, multiphasic CTA (12 phases with a temporal resolution of 3.5 sec) on a 128 slice CT-scanner with an average CM bolus of about 35 mL (BMI < 27 => 30 mL CM and 80kV/120mAs; BMI ≥ 27 => 40 mL CM and 100kv/120 mAs). Maximal HU-values in the iliac, renal artery, and renal vein as well as the CNR (contrast to noise ratio) and image noise were quantified. Furthermore diagnostic quality of CTA-data regarding renal vessels, cortex-medulla differentiation, and depiction of renal parenchyma were analysed in a consensus reading using a 4 point rank scala (1 = excellent, 2 = good, 3 = diagnostic, 4 = nondiagnostic). Effective radiation doses were calculated.

36 patients (16 female, 20 male, mean age: 51.4 ±13.4 years, range 23-68) underwent dynamic renal CTA (CNR 25 ±15, SNR 14 ±2.8). Using the optimal of the 12 dynamic phases, max. mean attenuation in the iliac artery was 353 ±111 HU, in the renal artery 337 ±98 HU, and the renal vein 164 ±51 HU. The renal transplant arteries were excellently depicted in most cases (mean score, 1.11 ±0.32) and classified as diagnostic in all patients (100%). Renal veins were well assessable in 31 cases (mean score 2.11 ±0.6), but non diagnostic in 5 (14%) cases. The image quality score for cortex differentiation was 2.11 ±0.98. Renal parenchyma was well assessable in 31 cases (mean score 2.11 ±0.6), but non diagnostic in 5 (14%) cases. Overall, the average effective radiation dose was 13.7 ±5.1 mSv.

The optimized time-resolved, multiphasic CT protocol enables significant CM reduction, and provides excellent depiction of the renal transplant and renal vasculature. In addition, effective radiation dose was maintained within an adequate range.

Patients with impaired renal function and high risk of contrast induced nephropathy may benefit from dynamic renal CTA given the very limited amount of required CM.

Helck, A, Bamberg, F, Sommer, W, Becker, C, Reiser, M, Nikolaou, K, Clevert, D, Notohamiprodjo, M, Wessely, M, Optimized Contrast Volume for Dynamic CT Angiography in Renal Transplant Patient Using a Multiphasic CT Protocol.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9007968.html