IT has been proposed that iodine-123 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (123I-BMIPP) is an agent for myocardial fatty acid metabolism in animal models. The aim of the present study was to determine whether alterations in fatty acid uptake and/or utilization in patients with hypertrophic cardiomyopathy (HCM) could be detected by 123I-BMIPP. Myocardial imaging with 123I-BMIPP and thallium-201 (201Tl) was performed in 14 fasted patients. A dose of 111 MBq of 123I-BMIPP was administered intravenously at rest, and myocardial emission computed tomography was obtained 20 min and 3 h after injection. The 201Tl imaging was also performed within 1 week after the 123I-BMIPP study. The regional myocardial uptake and clearance of 123I-BMIPP and 201Tl were assessed quantitatively. The myocardial distribution of 123I-BMIPP was more heterogeneous than that of 201Tl in patients with HCM. The myocardial uptake of 123I-BMIPP was lower in the anteroseptal region of the left ventricle than in the posterolateral region (74% vs. 85%, P less than 0.001). The anteroseptal wall showed a faster clearance of 123I-BMIPP than the posterolateral wall (33% vs. 27%, P less than 0.01). Both a decreased uptake and rapid clearance of 123I-BMIPP were observed in the hypertrophied myocardium of the anteroseptal wall, where 201Tl uptake was normal or even increased. Myocardial segments with a markedly increased thickness showed a lower uptake and faster clearance of 123I-BMIPP than those with mild hypertrophy (uptake 73% vs. 82%, P less than 0.05; clearance 30% vs. 25%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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Objective-Exercise thallium-201 ('0OTI) single photon emission computed tomography (SPECT) has been used to detect potential ischaemia in the left ventricular myocardium but not in the right ventricle. The purpose of this study was to establish the clinical usefulness of a right ventricular polar map of 205'T SPECT for visualisation of exercise-induced right ventricular ischaemia. Methods-Myocardial 20TlI SPECT was obtained immediately after treadmill exercise in 97 patients with suspected coronary artery disease. A region of interest was placed over the right ventricle (RV) on post-stress transaxial images. Short axis images of this region were generated and reconstructed as a bull's eye polar map. Normal ranges of RV 201'n uptake were determined in 12 patients with normal coronary arteries. Scintigraphic criteria for identifying RV perfusion abnormality were derived from 25 patients with right coronary artery (RCA) stenosis greater than 75%. These criteria were applied to 60 consecutive patients with suspected coronary artery disease. Results-Perfusion defects in the RV were larger in patients with proximal RCA stenosis than in those with distal RCA stenosis (mean (SD) 28 (16)% v 6 (5)%, P < 0.001). The sensitivity and specificity of the RV polar map for the detection of proximal RCA stenosis were 67% (8/12) and 98% (47/48), respectively. RV perfusion defects became undetectable in 9 patients who had successful percutaneous transluminal coronary angioplasty to a proximal RCA lesion. Conclusions-A right ventricular polar map display was useful for visualising exercise-induced right ventricular ischaemia. (Heart 1997;77:40-45) Keywords: thallium-201; right ventricle; ischaemia; SPECT Exercise-induced right ventricular ischaemia is occasionally detected by currently available methods, such as an abnormal ejection fraction response to exercise or reduced regional wall motion on radionuclide ventriculography" 2 or on cross sectional echocardiography.3Myocardial perfusion imaging with thallium-201 (207T1) has been accepted widely as a practical and sensitive tool for assessing acute or chronic coronary artery disease. Reduced perfusion was rarely detected in patients with functional abnormalities in the right ventricle.4 However, several reports have commented that perfusion defects in the right ventricle were detectable by exercise planar 207T1 imaging in patients with right coronary artery disease.56 DePuey et a17 have also showed that myocardial single photon emission computed tomography (SPECT) with technetium-99m sestamibi but not 201T1 detected abnormal distribution of right ventricular perfusion.The purpose of the present study was (a) to visualise 207T1 uptake of the right ventricle on a bull's eye polar map, (b) to examine the sensitivity and specificity of the present image analysis of a exercise myocardial perfusion test, and (c) to assess the effect of percutaneous transluminal coronary angioplasty (PTCA) of the stenosed right coronary artery on right ventricular myocardial perfusion. Patients...

Advanced coronary artery disease, defined as left main or three-vessel coronary disease, was identifiable noninvasively by means of adenosine Tl-201 single photon emission tomography. Among 75 consecutive patients with angiographically documented coronary artery disease, there were 11 patients with the presence (group 1) and 64 patients with the absence (group 2) of advanced coronary artery disease. The lung-to-heart ratio (L/H ratio) of Tl-201 uptake was calculated as the fraction of average Tl-201 counts per pixel in the lung divided by those in the myocardium. The left ventricular dilation ratio (LVDR) was determined as a ratio of left ventricular cavity size in the early image to that in the delayed image. The patients in group 1 had more defects (2.3 +/- 0.6 seg. vs. 0.9 +/- 0.7 seg., p < 0.001), a higher L/H ratio (35 +/- 4% vs. 28 +/- 5%, p < 0.001) and a higher LVDR (1.13 +/- 0.04 vs. 1.06 +/- 0.04, p < 0.001) than those in group 2. The diagnostic accuracy of the identification of advanced coronary artery disease was 89% by perfusion defects, 68% by L/H ratio and 81% by LVDR. Stepwise discriminant analysis revealed that LVDR (F = 36.2, p < 0.0001) and perfusion defects (F = 8.9, p < 0.004) were the significant and independent discriminators of advanced coronary disease. Identification of patients with left main or three-vessel coronary disease was enhanced by additional analysis of cavity dilation of the left ventricle and increased Tl-201 activity in the lung.

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