Abstract 12178: Photon Counting Computed Tomography for Aortic Valve Calcium Scoring in Contrast- Enhanced Datasets of the Heart

Abstract

Introduction: The prognostic value of aortic valve calcium in patients prior to TAVR is well established. Its reliable quantification requires a non-contrast CT of the heart (‘true non contrast’, TNC) which in this cohort is not regularly performed at all centers. Photon Counting Detector CT (PCD-CT) permits the routine derivation of ‘virtual non-contrast’ (VNC) series from CT Angiography (CTA) acquisitions due to its intrinsic spectral sensitivity. These might render separate non-contrast acquisitions unnecessary. The aim of our study was to evaluate the feasibility of aortic valve calcium quantification on VNC series derived from CTA scans. Methods: All patients underwent TAVR planning CT on a novel PCD-CT (NAEOTOM Alpha, Siemens Healthineers, Erlangen, Germany) comprising a non-contrast CT of the heart, followed by a CTA of the heart, aorta and iliac arteries. VNC series were derived from CTA acquisitions and two readers independently quantified aortic valve calcium scores and volumes on VNC- and TNC-series. Results: Here, we report initial results of the first 5 of 100 patients. In comparison with those derived from TNC series, calcium scores and volumes derived from VNC series were consistently lower (mean 713 vs. 1110 and 563 vs. 894 mm 3 ) but correlation was excellent for both calcium score and volume (r’s: 0.945 and 0.938, respectively, both p’s=0.01). Conclusions: Our initial patient experience with TAVR planning CT on a novel PCD-CT shows excellent correlation of aortic valve calcium scores and volumes derived from VNC series, as compared with those derived from TNC series. These will most likely be interchangeable, thus rendering non-contrast acquisitions redundant for TAVR planning. Figure 1 Corresponding series of a TAVR patient with high-grade aortic stenosis demonstrating severe aortic valve calcifications on (A) true non-contrast CT (TNT-Score: 3772), (B) CTA for annulus measurement and (C) VNC-reconstructions derived from CTA (VNC-Score: 3099).