Sara Kruglick Floyd MD, Presenter: Nothing to Disclose

Olga Buzdygan, Abstract Co-Author: Nothing to Disclose

Marcos Paulo Ferreira Botelho MD, Abstract Co-Author: Nothing to Disclose

Timothy J. Carroll PhD, Abstract Co-Author: Nothing to Disclose

Ronan Conroy, Abstract Co-Author: Nothing to Disclose

Sukit C. Malaisrie MD, Abstract Co-Author: Nothing to Disclose

Jeremy Douglas Collins MD, Abstract Co-Author: Consultant, B. Braun Melsungen AG

James Christopher Carr MD, Abstract Co-Author: Research Grant, Astellas Group Research support, Siemens AG Speaker, Siemens AG Advisory Board, Guerbet SA

CT angiography (CTA) is required prior to Transcatheter Aortic Valve Implantation (TAVI), in order to accurately size the aortic valve and ensure that the pelvic vessels are sufficiently large to accommodate vascular access. Due to advanced age and associated vascular disease, many TAVI patients suffer from chronic kidney disease and are thus at increased risk of contrast induced nephropathy (CIN). We hypothesize that diagnostic pre-procedural planning can be obtained using a low dose contrast CTA protocol, thereby reducing the risk of CIN.

A consecutive series of 65 CTA examinations, performed on a dual source 64 slice CT scanner (Siemens Definition), were retrospectively identified for patients being considered for TAVI. The cases were divided into low dose (<90ml contrast) and standard dose (≥90ml contrast) groups. Quantitative analysis of image quality was calculated by measuring signal to noise (SNR) and contrast to noise (CNR) at 10 pre-determined anatomic sites in the thoracic and abdominal aorta. Qualitative image analysis was determined by two blinded physician reviewers, independently rating each site on a 1-5 Likert scale, with respect to image quality, diagnostic confidence, SNR and CNR. Results between the low dose and standard dose groups were compared using a weighted kappa statistic.

Quantitatively, SNR and CNR were lower in the low dose group compared to the standard dose group (SNR 17.7 compared to 35.8, CNR 14.8 compared to 30.7). For image quality, the low dose group scored 3.67 on average compared to 3.88 in the standard dose group. Average diagnostic confidence scores were 3.96 for low dose compared to 4.26 for standard dose. Average qualitative CNR was 3.65 for low dose compared to 4.22 for standard dose. Average qualitative SNR was 3.44 for low dose compared to 3.79 for standard dose. The weighted kappa statistic was 0.5873, indicating a moderate degree of agreement between reviewers.

Low dose CTA had lower image quality but acceptable diagnostic confidence compared to standard dose CTA. In patients with renal compromise, low dose CTA may be a safer alternative in pre-procedural TAVI planning.

CT angiography (CTA) is required for pre-procedural assessment of aortic stenosis patients prior to Transcatheter Aortic Valve Implantation (TAVI). Low dose CTA may be a safer alternative.

Floyd, S, Buzdygan, O, Botelho, M, Carroll, T, Conroy, R, Malaisrie, S, Collins, J, Carr, J, Low Dose CT Angiography for Pre-procedural Assessment of Patients Undergoing TAVI.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045436.html