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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.

Objectives To determine the incremental benefit of assessing myocardial perfusion defects (MPD) for acute coronary syndromes (ACS) over coronary and functional assessment by rest cardiac computed tomography (CT) in patients with acute chest pain. Background Assessment of myocardial perfusion is feasible with cardiac CT; however, the diagnostic value of this assessment in patients at risk for ACS has not been demonstrated. Methods The study included patients who presented to the emergency department with acute chest pain, nonischemic initial electrocardiogram (ECG), and negative cardiac biomarkers but had clinical suspicion for ACS and underwent invasive coronary angiography (ICA). Results were blinded to caregivers and patients. CT data sets were independently assessed for the presence of coronary plaque and stenosis, regional left ventricular function, and myocardial perfusion deficits by 2 blinded observers. Coronary angiography was assessed for the presence of stenosis, TIMI myocardial perfusion grade, and corrected TIMI frame count. The endpoint was ACS during index hospitalization. Results We analyzed data from 35 subjects (69% male, mean age 58 ± 9 years) of whom 22 (63%) had ACS. The sensitivity and specificity of MPD for ACS were 86% (95% CI: 64%–96%) and 62% (95% CI: 32%–85%), respectively. Combined, MPD and RWMA assessment resulted in specificity and sensitivity of 86% (95% CI: 64%–96%) and 85% (95% CI: 54%–97%), respectively. Adding MPD and RWMA to the assessment for significant stenosis (>50%) resulted in a higher sensitivity of 91% (69–98%) and specificity of 85% (54–97%) and a significantly increased overall diagnostic accuracy when compared with assessment for stenosis (AUC: 0.88 vs 0.79; respectively, P = 0.02). Diagnostic accuracy of CT was not associated with impaired CTFC >40 or myocardial TIMI perfusion grade Conclusions Assessment of myocardial perfusion and regional wall motion abnormalities may enhance the ability of CT to detect ACS in patients with acute chest pain.

In addition to accurately diagnosing coronary artery disease, cardiac CT (CCT) has the potential to provide information on myocardial function, perfusion, and viability. As ongoing research continues to support the utility of such noncoronary uses of CCT, this information is increasingly being integrated into clinical practice. An emerging important use of CCT is the ability to accurately identify areas of infarcted myocardium. From a clinical perspective, detecting and quantifying infarct size has important prognostic and therapeutic implications. This article provides a brief overview on the use of CT to diagnose myocardial infarction (MI) and provide practical "tips and tricks" that can aid in the CT-based detection of MI.

b A 37-year-old woman presented to the emergency artment (ED) with atypical substernal chest tightne here were no associated symptoms, and the discomfort ot radiate nor was it related to exertion. Examina lectrocardiogram (ECG), and laboratory studies, includi ardiac enzymes and D-dimer, were within normal lim hile in the ED, the patient underwent cardiac CT as f a research study, using tube current modulation to min mize exposure. CT images showed the absence of therosclerotic plaque, cine images showed norm lobal and regional left ventricular function, and no ndocardial perfusion defects were present. Of inter o right coronary artery ostium was visualized in atient. It was instead discovered that the patient h ingle coronary artery originating from the left sinu alsalva (Fig. 1). After branching from the left main he left anterior descending artery, the left circum