Transient Ischemic Dilation Ratio Research Articles

Transient ischemic dilatation ratio before and after CABG in patients with severe coronary artery disease assessed with stress/reinjection TL-201 ECG-gated SPECT: S. Kubo, E. Tadamura, T. Kudoh, M. Inubushi, N. Hattori, T. Koshiji, K. Nishimura, M. Komeda, J. Konishi

Transient ischemic dilatation ratio before and after CABG in patients with severe coronary artery disease assessed with stress/reinjection TL-201 ECG-gated SPECT: S. Kubo, E. Tadamura, T. Kudoh, M. Inubushi, N. Hattori, T. Koshiji, K. Nishimura, M. Komeda, J. Konishi

An automatic approach to the analysis, quantitation and review of perfusion and function from myocardial perfusion SPECT images.

We have developed a software suite that automatically selects, analyses, quantitates and displays all the key image data in a myocardial perfusion SPECT study. The files automatically selected (upon specification of the patient name) are rest and stress projections, rest and stress short axis and gated short axis files, and all 'snapshot' files. The projection data sets are presented in cine mode for evaluation of patient motion, while the lung/heart ratio at rest and stress is calculated from regions of interest (ROIs) that are automatically derived and overlayed on the LAO 45 images. Left ventricular (LV) cavity volumes at rest and stress are calculated from the short axis data sets, and the related transient ischemic dilation (TID) ratio derived and displayed. Quantitative measurements of global (ejection fraction) and regional function parameters are performed from the gated short axis dataset. All algorithms use the C++, X-Windows and OSF-Motif standards. The overall suite executes in less than 1 minute on a SunSPARC5 with 32 Mb of RAM and no proprietary hardware. The software was validated on 144 patients (118 rest 201T1/post-stress 99mTc-sestamibi, 18 post-stress 99mTC-sestamibi, 8 rest 201Tl) acquired on a 90 degrees dual detector (ADAC Vertex, 91 patients) and a triple detector camera (Picker Prism 3000, 53 patients). Overall, the individual algorithms for the analysis of projection, short axis and gated short axis images were successful in 622/660 (94.2%) of the images. In 80.5% of the patients (73/91 + 43/53) all algorithms executed successfully, without significant difference in success rates for 201Tl versus 99mTc-sestamibi images. Our automated approach to myocardial perfusion SPECT analysis and review is highly successful, intrinsically reproducible, and can produce time and cost savings while improving accuracy in a clinical or teleradiology-type environment.

Identification of severe and extensive coronary artery disease by automatic measurement of transient ischemic dilation of the left ventricle in dual-isotope myocardial perfusion SPECT

Objectives. This study sought to assess whether a transient ischemic dilation ratio, determined from automatically derived stress and rest left ventricular volumes during stress technetium-99m (Tc-99m) sestamibi/rest thallium-201 dual-isotope myocardial perfusion single-photon emission computed tomography (SPECT), is useful for the identification of patients with severe and extensive coronary artery disease.Background. Transient ischemic dilation of the left ventricle on stress/redistribution thallium-201 scintigraphy has been shown to be a clinically useful marker of severe and extensive coronary artery disease. However, in practice, its assessment is highly subjective. This study automatically assessed the transient ischemic dilation ratio on the basis of a previously described algorithm to estimate three-dimensional ventricular boundaries.Methods. Normal limits for the transient ischemic dilation ratio were developed using data from 54 patients with a low likelihood (<5%) of coronary artery disease, and criteria for abnormality were developed based on data from 97 who underwent catheterization, of whom 34 had severe and extensive coronary artery disease, defined as ≥90% stenosis in the proximal left anterior descending coronary artery or in two or more coronary arteries, and 63 had no coronary artery disease (15 patients) or mild to moderate coronary artery disease (48 patients). The criteria were then tested in a validation cohort of 77 additional patients who underwent catheterization, of whom 36 had severe and extensive coronary artery disease. The quantitative results of the dilation ratio were compared with the visual results of the dilation ratio and perfusion defect analysis.Results. For normal limits, receiver operating characteristic curve analysis showed that abnormal transient ischemic dilation ratio values corresponded to left ventricular endocardial volume ratios > 1.22 (mean ± 2 SD). Transient ischemic dilation assessment using these criteria for abnormality showed high sensitivity (24 [71%] of 34) and very high specificity (60 [95%] of 63) for severe and extensive coronary artery disease. When the analysis was applied to the prospective catheterization group, similar sensitivity and specificity for severe and extensive coronary artery disease were observed (77% and 92%, respectively). Significant agreement (p = 0.0001) was found between the degree of transient ischemic dilation and the Tc-99m sestamibi defect extent, the latter assessed by semiquantitative visual analysis (summed stress score).Conclusions. The automatic measurement of transient ischemic dilation in dual-isotope myocardial perfusion SPECT is a clinically useful marker that is sensitive and highly specific for detection of severe and extensive coronary artery disease.