Nevein F. Ibrahim MD, Presenter: Nothing to Disclose

Lance T. Hall MD, Abstract Co-Author: Nothing to Disclose

Mary L Zasadil MD, Abstract Co-Author: Nothing to Disclose

Derek E Fuerbringer, Abstract Co-Author: Nothing to Disclose

Alejandro Munoz Del Rio PhD, Abstract Co-Author: Research Consultant, Cellectar Biosciences, Inc Reviewer, Wolters Kluwer nv

Scott B. Perlman MD, Abstract Co-Author: Nothing to Disclose

There is a concerted effort to reduce radiation exposure in medical imaging, including myocardial perfusion imaging. The aim of this study is to investigate if the semi quantitative and qualitative myocardial perfusion SPECT parameters are jeopardized in patients with high body mass index (BMI) by using a half dose protocol and a new reconstruction algorithm.

We prospectively studied 59 patients referred for clinical rest/stress 99mTc-Sestamibi myocardial perfusion SPECT. The BMI range was 21.4- 48.6. All patients underwent half dose full time acquisition protocols for both rest and stress scans. Patients received intravenous injection of 218.3±18.5MBq 99mTc-Sestamibi at rest and 621.6 ± 51.8 MBq at stress, adjusted for weight. Total counts in both a superior and inferior myocardial region of interest (ROI) were acquired for 1 minute. Scans were processed using Evolution for Cardiac (Myovation Evolution, GEMS) software that incorporates iterative reconstruction algorithms with resolution recovery (RR) and noise-reduction technology. CT-based attenuation correction was acquired for all studies for both rest and stress. The images were interpreted blindly by two experienced readers. All images were qualitatively assessed by using 2 parameters: attenuation artifacts and interpretability.

Analysis of the quantitative count data for both the superior and inferior ROIs showed a decrease in the photon counts in patients with higher BMIs. A separate logistic regression model was run for each reader. Attenuation correction improved image quality for all BMIs. Both readers agreed that attenuation artifacts were more significant with higher BMI on both the rest and stress images and on both attenuation corrected and non-corrected images. All the studies were rated as interpretable/diagnostic by both readers.

Despite a decrease in count rates and increase in attenuation artifacts in patients with high BMI, image interpretability is not affected using a new half-dose protocol. Therefore, the half dose protocol with the new reconstruction algorithm can be used for patients with high BMI and thus reduce radiation exposure.

Incorporating the new reconstruction algorithm to myocardial perfusion SPECT made it possible to decrease radiation dose without jeopardizing scan interpretability, even for patients with high BMI.

Ibrahim, N, Hall, L, Zasadil, M, Fuerbringer, D, Munoz Del Rio, A, Perlman, S, Half Dose Myocardial Perfusion SPECT: Is It Possible for Patients with a High BMI?.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011293.html