Biomedical subjects
Publications and source records attributed to T Kozuka.
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For diagnosing myocardial infarction by myocardial scintigraphy using 201TlCl, the following two items were compared: 1) The diagnostic accuracy of visual evaluation of myocardial planar images versus that of single photon emission computed tomography (SPECT) images. 2) The diagnostic accuracy of qualitative and quantitative evaluations of SPECT images. The planar and SPECT methods were performed for 81 subjects consisting of 41 patients having myocardial infarction and 40 normal persons. Receiver operator characteristic (ROC) analysis, which is most objective in evaluation of visual diagnosis, was also used. To analyze quantitative diagnosis by ROC analysis, the normal range of circumferential profile analysis of myocardial short-axial tomography was determined by assessing five step divisions (less than 1 SD, 1-1.7 SD, 1.7-2.3 SD, 2.3-3 SD, and more than 3 SD) from 10 normal cases. Four physicians and three laboratory technicians familiar with myocardial images diagnosed the myocardial planar images and SPECT images individually. The results were analyzed and the ROC curves were constructed. The results indicated that image diagnosis by SPECT was superior to that by the visual planar method for all persons. The physicians who had more experience in diagnosing myocardial images made more accurate diagnosis. However, quantitative SPECT image diagnosis was superior to visual SPECT image diagnosis. Thus, with the input of data of the normal range of quantitative SPECT image diagnosis into the computer, the prospects of accurate computer assessments of myocardial infarctions were posed.(ABSTRACT TRUNCATED AT 250 WORDS)
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One hundred and eight cases with ischemic heart disease except for acute myocardial infarction were examined by cardiac computed tomography with ECG-gated scanning. The right ventricular (RV) wall contractility was evaluated by the long-axial and short-axial CT images in terms of (a) contraction rate of the RV area, (b) shortening rate of the RV free wall and (c) changes in the thickness of the RV free wall in cardiac cycle. These parameters were compared to the findings of coronary angiography and left ventriculography. 1. There was no difference of the contraction rate of the RV area between the cases with severe (90-100%) right coronary (RCA) stenosis and those with mild (0-75%) stenosis, while the contraction rate of the RV area was markedly decreased in the former combined with the impaired contraction of the ventricular septum. Consequently, it was assumed that RV function is hardly damaged by RCA lesion alone, and that the contraction rate of the RV area is not a suitable parameter for the assessment of the severity of RCA stenosis. 2. The shortening rate of the RV free wall in the long-axial image in cases with severe RCA stenosis was significantly decreased (14.5 +/- 4.6%) compared with that of mild stenosis (27.8 +/- 5.0%). The changes in the thickness of the RV free wall were also impaired in severe RCA stenosis. Same tendency was observed in the short-axial image, while the correlation between RCA stenosis and impaired contraction of the RV free wall was much more evident in the long-axis image than in the short-axis image. As the result, reduced RV contraction due to RCA ischemia seems to exist not only in acute myocardial infarction but also in chronic stage of the ischemic heart. 3. CT method is suitable for the evaluation of RV ischemia due to RCA lesion because the contractility of the RV free wall can be assessed independently of ventricular septal contraction. In cases with reduction of the free wall shortening rate under 20% combined with poor change in the thickness of the RV free wall, severe stenosis of the RCA should be suspected.
Thallium-201 myocardial imaging was performed at rest in 131 children with coronary arterial lesions due to Kawasaki disease. The coronary arterial lesions were assessed by selective coronary angiography within a few days of the isotope study. Twenty-one children had occlusive lesions, and segmental stenotic lesions were seen in 16 children. Perfusion defects of the myocardial images were detected in nine of the former and in three of the latter. The locations of the perfusion defects coincided with the perfusion areas of the affected vessels on coronary angiography. Twelve patients with initial perfusion defects at rest had a follow-up study and the defects disappeared in five. These patients had re-establishment of coronary blood flow in the initially affected areas by either development of collateral vessels or recanalization. Myocardial imaging with exercise was performed in 27 patients including four with coronary arterial occlusion and two with segmental stenosis on coronary angiography. All with coronary artery lesions showed perfusion defects on the imaging with exercise, while the resting study showed the defects only in one patient, in whom more extensive perfusion defects were observed after exercise. Myocardial imaging following intravenous injection of dipyridamole was carried out in 43 patients. Perfusion defects after the injection were noted in 15 of 17 patients with coronary occlusion and in nine of 13 patients with segmental stenosis. In four patients with perfusion defects at rest, additional or more extensive defects were revealed by this drug in the areas of additional coronary arterial involvements. In 20 patients with perfusion defects only after dipyridamole injection, the perfusion defects coincided with the angiographic findings very well. A perfusion defect was documented following dipyridamole injection in one exceptional patient who had no stenotic lesions, but had three giant coronary aneurysms of the right coronary artery. Thus the dilated coronary lesions seemed to give a perfusion defect. In some of the patients whose perfusion defects disappeared at rest on a follow-up study, the defects were disclosed by exercise and/or dipyridamole administration. Thus, thallium-201 myocardial imagings combining resting and exercise or dipyridamole studies were valuable for the detection and assessment of coronary arterial lesions of Kawasaki disease.
Thallium-201 myocardial imaging was performed for 77 patients with congenital heart disease to evaluate myocardial damage following open-heart surgery. There were 23 patients with ventricular septal defects, 33 with tetralogy of Fallot, 12 with atrial septal defects, and nine with other diseases. The imaging results were compared with the angiographic and electrocardiographic findings. Patchy perfusion defects or images of poor thallium uptake were noted in five of 77 patients, among whom four had accompanying serious ventricular arrhythmias. This suggested a close correlation of the post-operative ventricular arrhythmias with myocardial damage. For 20 of 77 patients, vents were inserted through the left ventricle, and for the remaining 57 through the left atrium. Perfusion defects were found at the apex in three, and left ventriculography showed a paradoxical motion of the apex in five in patients whose vents were inserted through the left ventricle. Sensitivity and specificity in detecting myocardial damage of the apex were 60% and 98%, respectively. In one case, myocardial infarction was demonstrated immediately after the repair of the ventricular septal defect. Myocardial imaging was useful in evaluating the infarcted area and for follow-up study. Thus, thallium-201 myocardial imaging was regarded useful for assessing myocardial damage following open-heart surgery in congenital heart disease patients.
The present study quantitatively analyzed the shortening fraction of regional wall motion (RWM) of the right ventricle (RV) in 18 patients with obstruction of the right coronary artery due to the mucocutaneous lymph node syndrome (MCLS). None of the patients had any apparent lesion of the left coronary artery by selective coronary angiography. The radial approach was used except for the right ventricular outflow tract in the lateral view, using the Siemens AVD system. There was no correlation between the occlusion and segmental stenosis, nor was there any correlation between dysfunction of the RWM of the RV and the posterior wall of the left ventricle (LVPW). The second cineangiography one year later showed that shortening of three segments (II, III, and VIII) of the RV was significantly reduced, as compared with that during the first study. We believe that dysfunction of the LVPW may not be contributory in diagnosing RV infarction. Not only LV-graphy, but RV-graphy as well, are recommended for patients with RV dysfunction due to obstruction of the right coronary artery in the MCLS.
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The relevance of arachidonic acid metabolites in inflammatory skin diseases has been expanded by recent developments in analytical chemistry. The metabolites include prostaglandins, leukotrienes and monohydroxy fatty acids. In ultraviolet light-induced inflammation the concentrations of arachidonic acid, prostaglandin E2, prostaglandin F2 alpha and 6-oxo-prostaglandin F1 alpha are elevated. Indomethacin totally suppresses the evoked prostaglandin increase, but erythema is only partially suppressed. This indicates that prostaglandins are partially involved in erythema production. In psoriasis the first histological change is an infiltration into the epidermis by neutrophilic leucocytes. It has been suggested that chemotactic factors, such as complement derived factors or leukotriene B4 play a role in the pathogenesis of psoriasis.