Brandon Augustus Howard MD, Presenter: Nothing to Disclose

Jorge Daniel Oldan MD, Abstract Co-Author: Nothing to Disclose

Robert Pagnanelli RT, Abstract Co-Author: Nothing to Disclose

Salvador Borges-Neto MD, Abstract Co-Author: Speakers Bureau, General Electric Company

Cadmium-zinc telluride (CZT) detectors promise improved resolution, scan times, and radiation dose in myocardial perfusion imaging (MPI). Traditional Anger cameras suffer from attenuation artifact, which in men is seen in the inferior wall. Specificity for CAD reportedly improves when prone imaging is added to supine imaging, and this practice has become commonplace. However, a systematic study of the difference in uptake between prone and supine imaging has not been undertaken.

Twenty patients referred for MPI underwent rest (supine and prone) and stress (supine and prone) Tc-99m tetrofosmin imaging on a CZT camera (GE Discovery NM 530c) between Oct. and Nov. 2013. One patient was excluded due to bowel uptake. Patient were 18 males and 1 female, with ages 35-76 (mean 60). Thirteen had known CAD and 6 had cardiac risk factors. Two board certified nuclear medicine physicians who were blinded to the clinical information, stress test results, and gated study scored perfusion using the 17 segment model and five point scale. Mean perfusion score (MPS) was computed for each segment and summed rest and stress scores (SRS, SSS) for each of the four conditions. Student’s T test with Bonferroni correction was used for statistical analysis.

SSS significantly decreased from supine to prone (SP) (p=.000622). Perfusion in the basal inferior wall significantly increased from supine to prone at rest (p=0.0013) and at stress (p=0.0000000103). Removal of the basal inferior segment abolished the difference in SSS. Trends from SP not meeting cut-off for significance (p< .00147) were as follows: rest perfusion increased in the mid- inferior segment (p=.00592); stress perfusion increased in the basal inferoseptal, mid- inferoseptal, and mid- inferior segments (p=.00447, p=.00231, and p=.00325, respectively). No other significant differences were noted.  

Prone imaging results in an overall decrease in summed stress score (SSS) compared to supine, and this difference is solely due to increased tracer uptake in the basal inferior segment on prone. Perfusion in the basal inferior segment is also significantly greater on prone than supine imaging at rest, with no significant difference in SRS.

Prone imaging results in increased tracer uptake in the basal inferior wall at stress and rest versus supine, and decreases overall summed stress score. Further study of prognostic and gender-specific effects is needed.

Howard, B, Oldan, J, Pagnanelli, R, Borges-Neto, S, Characterization of the Difference in Appearance between Supine and Prone Myocardial Perfusion Imaging on a High-efficiency Pinhole SPECT System.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013403.html