[Increased lung uptake and transient left ventricular dilatation at stress myocardial scintigraphy with 99mTc-MIBI]

On exercise 201Tl scintigraphy in coronary artery disease, left ventricular transient dilatation (LVTD) and increased lung uptake were noted as a marker of multivessel critical stenosis. To compare the two markers of 99mTc-methoxyisobutyl isonitrile (MIBI) and 201Tl, planar and SPECT myocardial scintigraphy were performed with both radiopharmaceuticals in 27 patients with ischemic heart disease. Lung uptake (lung/max myocardial ratio) of MIBI was significantly lower than that of 201Tl, but the relationship of the lung uptake was linearly correlated (r = 0.77). The LVTD ratio (mean radial ratio = m-RR) was determined by the mean radius of the immediate postexercise short axial image by that of rest (redistribution) image. There was no significant correlation between the m-RR of 201Tl and that of MIBI (r = 0.27). We suggest that the mechanism of LVTD is due to not only subendmyocardial ischemia but also another factors.