Document Type : Original Article
Nuclear Medicine and Molecular Imaging Research Center, Namazi Teaching Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
Introduction: For the interpretation of myocardial perfusion imaging, considering non-perfusion variables, such as transient ischemic dilatation (TID), are also important in diagnostic and prognostic evaluation of a patient. TID has a relatively high false positive and false negative results, which reduces its diagnostic and prognostic values. In this study, we aimed to compare the accuracy of TID after normalization based on changes in LV wall mass.
Methods: Patients referred for dipyridamole myocardial perfusion imaging single-photon emission computed tomography (MPI/SPECT), one to two year prior to the study with TID ratio >1 were enrolled. Patients with any previous history of revascularization and structural heart disease were excluded. Follow-up was done by phone call. The occurrence of cardiac death, myocardial infarction, revascularization or evidence of abnormal angiography during one year after MPI was considered positive for short-term cardiac events. The corrected TID (cTID) was calculated by the following formula: cTID = TID/(Wallstress/Wallrest).
Results: Among 196 participants, 30 (15%) had cardiovascular events during the follow-up. The area under the receiver operating characteristic (ROC) curve for the short-term prognosis of the cardiac events were 0.57 and 0.50 for cTID and TID with a p-value of 0.17 and 0.92, respectively. Considering the best cut-off points that were achieved by ROC curves, cTID showed significant odds ratio (OR: 2.53) for prediction of short-term cardiac events, while respecting, TID failed to be statistically significant.
Conclusion: Making correction on TID using LV wall volumes can improve short-term prognostic value of this variable.