Yuki Tanabe, Presenter: Nothing to Disclose

Teruhito Kido MD, PhD, Abstract Co-Author: Nothing to Disclose

Takahiro Yokoi, Abstract Co-Author: Nothing to Disclose

Shintaro Tsuruoka, Abstract Co-Author: Nothing to Disclose

Naoki Fukuyama, Abstract Co-Author: Nothing to Disclose

Takuya Matsuda, Abstract Co-Author: Nothing to Disclose

Rami Yokoyama, Abstract Co-Author: Nothing to Disclose

Masashi Nakamura, Abstract Co-Author: Nothing to Disclose

Yoshiko Nishiyama MD, Abstract Co-Author: Nothing to Disclose

Masao Miyagawa MD, PhD, Abstract Co-Author: Nothing to Disclose

Teruhito Mochizuki MD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to investigate the optimal timing of single-phase CT perfuion (CTP) scan for differentiation of ischemic and normal myocardium.

The study group comprised 21 patients (mean age 68.7±7.5 years) who underwent ATP-stress dynamic myocardial CTP scan and invasive coronary angiography (ICA) and stress myocardial perfusion imaging (MPI) (SPECT or cardiac MRI). All patients in this study had one or two vessels disease. Dynamic CTP (whole heart datasets over 30 consecutive heart beats in systole without spatial and temporal gaps) was acquired with prospective ECG gating. Coronary stenosis ≧50% was defined as positive findings in ICA, and perfusion abnormalities were defined as positive findings in MPI. In this study, the areas with ICA (-) and MPI (-) are defined as normal, the areas with ICA (+) and MPI (+) as ischemia and the areas with ICA (+) and MPI (-) as non-ischemia. Results of ICA and MPI are analyzed according to 3 vessel areas (LAD, LCX, RCA). 2 experienced radiologists visually analyzed the dynamic CTP images in reference to the results of ICA and MPI and consulted together about the optimal scan timing for differentiation of ischemic and normal myocardium. Then, “static image” at the optimal scan timing was compared with “dynamic image” in the diagnostic performance for detecting myocardial ischemia by other 2 experienced radiologists visually analyzing.

Normal, ischemic and non-ischemic areas were 22/63, 29/63 and 12/63 areas. As a result of qualitative assessment, the optimal scan timing could be 1.8-2.5 seconds after peak enhance time of the aorta (mean ΔCT value (normal-ishcemia): 26.0±18.9 HU). 95% of all cases were included in this range. In “static CTP image” at the optimal timing, Sensitivity, specificity, positive predict value (PPV) and negative predict value (NPV) were 79.3%, 76.5%, 74.2% and 81.3%. In “dynamic CTP image”, Sensitivity, specificity, PPV and NPV were 82.8%, 79.4%, 77.4% and 84.4%.

In myocardial CTP imaging, the optimal timing of single-phase scan is 1.8-2.5 seconds after peak enhance time of the aorta, which will be helpful to optimize single-phase CTP scans.

Static CTP image by scanning at the optimal timing can decrease radiation exposure with keeping the diagnostic performance almost the same level of the dynamic CTP image.

Tanabe, Y, Kido, T, Yokoi, T, Tsuruoka, S, Fukuyama, N, Matsuda, T, Yokoyama, R, Nakamura, M, Nishiyama, Y, Miyagawa, M, Mochizuki, T, When Is Optimal Scan Timing in Static Myocardial CT Perfusion Imaging-by Whole Heart Dynamic Scan.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006424.html