A comparison of reconstruction and viewing parameters on image quality and accuracy of stress myocardial CT perfusion

Abstract

Background: Myocardial stress computed tomography perfusion (CTP) has similar diagnostic accuracy for detecting perfusion defects (PDs) versus single-photon emission computed tomography (SPECT). However, the optimal diagnostic viewing and image processing parameters for CTP are unknown.

Objective: We sought to compare the diagnostic accuracy of different image processing techniques, cardiac phases, slice thicknesses, and viewing parameters for detection of PDs.

Methods: A stress and rest dual-source CTP protocol was performed with adenosine. Twelve subjects with severe stenosis proven by quantitative coronary angiography (QCA), with corresponding territorial defects at SPECT, were selected as well as 7 controls (subjects with similar clinical suspicion but negative QCA and SPECT). Short-axis stress images were processed with 3 techniques: minimum intensity projection (MinIP), maximum intensity projection, and average intensity multiplanar reconstruction (MPR), 3 thicknesses (1, 3, 8 mm), and 2 phases (systolic, mid-diastolic). The resulting images (n = 1026) were randomized and interpreted by independent readers.

Results: Diastolic reconstructions (8-mm MPR) showed the highest sensitivity (81%) to detect true PDs. The highest accuracy was achieved with the 8-mm (61%) and 1-mm (61%) MPR diastolic images. The most sensitive and accurate systolic reconstructions were 3-mm MinIP images. These findings related to viewing in relatively narrow window width and window level settings.

Conclusion: Viewing parameters for optimal accuracy in detection of perfusion defects on CTP differ for systolic and diastolic images.

Conflict of interest statement

Conflict of interest: Astellas Pharmaceuticals Inc. provided grant support for the initial study. The authors maintained full control over this study design and data.

Copyright © 2011 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Inclusion/exclusion criteria and image randomization process: 50 subjects underwent initial feasibility trial of CTP, of which subjects were excluded because of QCA not being performed (n = 7), or discordance between defect territory between QCA and SPECT (n = 24). Of the remaining 19 subjects, 7 served as controls (ie, no significant defects at SPECT or no evidence of stenosis > 50% by QCA), and 12 served as positive cases (≥ 50% QCA, with a matching, at least moderate perfusion defect in the same territory at SPECT).

Figure 2

Effect of multiple reconstruction parameters on image characteristics: MPR (top row), MinIP (middle row), and MIP (bottom row) short-axis reconstructions through the same apical segment defect in the inferolateral wall of the left ventricle. The patient had subtotal circumflex occlusion at invasive angiography, as well as a corresponding inferolateral wall reversible defect on SPECT imaging. In this figure, display WW and WL are held constant (200/100).