[Clinical usefulness of myocardial iodine-123-15-(p-iodophenyl)-3(R,S)-methyl-pentadecanoic acid distribution abnormality in patients with mitochondrial encephalomyopathy based on normal data file in bull's-eye polar map].

Visual interpretation of iodine-123-beta-15-(p-iodophenyl)-3(R,S)-methyl-pentadecanoic acid (123I-BMIPP) myocardial images cannot easily detect mild reduction in tracer uptake. Objective assessment of myocardial 123I-BMIPP maldistributions at rest was attempted using a bull's-eye map and its normal data file for detecting myocardial damage in patients with mitochondrial encephalomyopathy. Six patients, two with Kearns-Sayre syndrome and four with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and 10 normal subjects were studied. Fractional myocardial uptake of 123I-BMIPP was also measured by dynamic static imaging to assess the global myocardial free fatty acid. These data were compared with the cardiothoracic ratio measured by chest radiography and left ventricular ejection fraction assessed by echocardiography. Abnormal cardiothoracic ratio and lower ejection fraction were detected in only one patient with Kearns-Sayre syndrome. Abnormal fractional myocardial uptake was detected in two patients (1.61%, 1.91%), whereas abnormal regional 123I-BMIPP uptake assessed by the bull's-eye map was detected in five patients (83%). All patients showed abnormal uptake in the anterior portion, and one showed progressive atrioventricular conduction abnormality and systolic dysfunction with extended 123I-BMIPP abnormal uptake. The results suggest that assessment based on the normal data file in a bull's-eye polar map is clinically useful for detection of myocardial damage in patients with mitochondrial encephalomyopathy.