Multidetector computed tomography pulmonary angiogram in the assessment of myocardial infarction

The objective of this study is to evaluate the effectiveness of nonelectrocardiographic gated multidetector computed tomography (MDCT) performed for the purpose of assessment of pulmonary embolus in the evaluation of myocardial infarction (MI).

We retrospectively evaluated 147 consecutive patients who had a computed tomography angiogram for pulmonary embolus on a 16-detector MDCT. Of this cohort, we determined 11 patients to have acute MIs based on electrocardiogram, positive troponin levels, and clinical findings and history. Four additional patients were found to have chronic MI based on history. The MDCT data were evaluated by an attending Radiologist, blinded to the clinical data, for quantitative and qualitative attenuations. Each MI was assigned a region of the heart based on its anatomical sections.

We were able to detect 10 of 15 MIs, resulting in an overall sensitivity and specificity of 66.6% and 91.4%, respectively. The overall accuracy was 76.7%. If non-Q wave MIs are excluded from the data set, the sensitivity increased to 76.9%. Quantitative analysis of each region of the heart showed that there was a statistically significant difference (P < 0.01) between the infracting regions of the heart (69 +/- 3.3 SEM) and those with normal perfusion (93.3 +/- 1.0 SEM).

While this method did prove to be effective at determining patients who had an MI, the low sensitivity and inability to differentiate chronic from acute myocardial infarction suggest that this technique is very limited in clinical practice.