A study presented at the European Congress of Radiology 2012 in Vienna, Austria, shows that the addition of computed tomography (CT) perfusion to CT angiography improves diagnostic accuracy of CT angiography in acute chest pain patients, primarily by reducing the rate of false positive exams. The study was presented by Gudrun Feuchtner’s group, from Innsbruck Medical University, Austria.
The investigation was performed at the Baptist Hospital of Miami, USA, and led by Ricardo C Cury. The objective of the study was to evaluate resting myocardial CT perfusion from coronary CT angiography datasets in patients presenting with chest pain to the emergency department, in comparison with myocardial SPECT.
Seventy six patients presenting with chest pain to the emergency department underwent coronary 64-slice CT angiography. The mean age was 54.9±13 years; 42% of the patients were females, 13% had prior coronary revascularisation and 16% had prior myocardial infarction.
Myocardial perfusion defects were evaluated for CT perfusion employing an AHA 17-segment model. CT perfusion results were compared to rest sestamibi SPECT myocardial perfusion imaging per-patient and per-segment. CT angiography was assessed for >50% stenosis per vessel and compared to stress/rest SPECT. Combined CT angiography/CT perfusion approach was tested using vessel territory-based method.
The results showed that, on a per-patient and per-segment basis, CT perfusion demonstrated sensitivity of 92% and 89%, specificity of 95% and 99%, positive predictive value of 80% and 82%, and negative predictive value of 98% and 99%, respectively. The intermodality agreement of CT perfusion to SPECT myocardial perfusion imaging was kappa=0.82 (p≤0.001).
CT angiography showed accuracy of 92%, sensitivity of 70.4%, specificity of 95.5%, positive predictive value 67.8%, and negative predictive value of 95% as compared to SPECT myocardial perfusion imaging. Addition of CT perfusion findings to CT angiography improved the positive predictive value from 67% to 90.1%, primarily by reducing false positives.
The authors of the study concluded that “in patients presenting to the emergency department with chest pain, the evaluation of rest myocardial CT perfusion demonstrates high diagnostic performance as compared to SPECT myocardial perfusion imaging. An additional read-out of myocardial perfusion defects on coronary CT angiography datasets improves the accuracy of coronary CT angiography in patients presenting with acute chest pain to the emergency department.”