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Biomedical subjects

T Ohtake

Publications and source records attributed to T Ohtake.

At least 145 records · Page 8Linked to original sources
PubMed1987

Evaluation of regurgitant fraction of the left ventricle by gated cardiac blood-pool scanning using SPECT.

Regurgitant fraction (RF) of patients with and without mitral regurgitation (MR) and/or aortic regurgitation (AR) was evaluated by gated cardiac blood-pool scanning using single photon emission computed tomography (SPECT). Using the stroke count image of a short-axis tomogram to separate the right atrium and ventricle, the left ventricular stroke count (LVSC) and right ventricular stroke count (RVSC) were determined. The RF equaled (LVSC - RVSC)/LVSC. Calculated RF in 14 subjects without significant regurgitation by contrast angiography was 5.8 +/- 5.9% (mean +/- s.d.), RF of 17 cases with angiographic regurgitation was 42.5 +/- 16.8% (p less than 0.001). The sensitivity of the radionuclide method compared to angiography was 94% (16/17 cases), and specificity was 100% (14/14 cases). RF of mild Re (1+ or 2+) was 26.0 +/- 8.9% (n = 6) and RF of severe Re (3+ or 4+) was 51.5 +/- 12.7% (n = 11) (p less than 0.001). Correlation between the RF determined with the radionuclide method and with cardiac catheterization was good (y = 5.85 + 0.700 x, r = 0.821, n = 17). We conclude that RF of MR and/or AR can be accurately evaluated by gated cardiac blood-pool scanning using SPECT.

Cardiac Catheterization↗
PubMed1986

Scintigraphic manifestation of fibrous dysplasia.

Scintigraphic manifestations of fibrous dysplasia were analyzed in 59 lesions of 26 patients (12 monostotic, 14 polystotic). Bone imaging with Tc-99m MDP revealed a high percentage of increased uptake of radioisotope in the lesions of fibrous dysplasia. Four (14%) of 29 cystic lesions and two (7%) of 30 lesions with the appearance of ground glass showed no increase in radioisotope uptake, although roentgenograms showed marked changes. Therefore, care must be taken in the diagnosis of fibrous dysplasia with bone imaging alone. Nuclear methods, however, are indispensable in evaluating the dynamic aspects of bone mineral behavior and in demonstrating disease where none was suspected, or in visualizing polyostotic involvement in those cases where only monostotic disease was suspected clinically. It is concluded that both scintigrams and roentgenograms are complementary procedures in the diagnosis of fibrous dysplasia.

Adolescent↗
PubMed1985

Effectiveness of ECG-gated magnetic resonance imaging in diagnosing cardiovascular diseases.

Nuclear magnetic resonance imaging (MRI) is a noninvasive method which can discriminate between flowing blood and vascular walls, and is expected to contribute to the diagnosis of cardiovascular diseases. Since the data acquisition by conventional MRI is too long for precise cardiac imaging, the ECG-gated method is mandatory in evaluating cardiac function and producing cardiac images of high quality. To evaluate the effectiveness of ECG-gated MRI, left ventricular wall motion and ejection fraction by MRI were compared with those obtained by radionuclide technique. Two types of MR imagers were used: one with a resistive magnet (0.15 Tesla) for 12 patients, and the other with a superconductive magnet (0.35 Tesla) for eight patients. MRI imaged cardiac muscle and vascular walls without the need for any contrast media or radionuclides. The superconductive apparatus provided better quality images than did the resistive one. Comparing MRI with radionuclide technique regarding left ventricular wall motion, resistive and superconductive MRI data correlated satisfactorily with those of radionuclide technique, except in the inferior wall, which was better evaluated by radionuclide technique. Left ventricular ejection fraction obtained by MRI was moderately lower than those obtained by radionuclide technique, though the correlation was good [r = 0.84 (resistive unit) and r = 0.85 (superconductive unit)]. In addition to three-dimensional morphological information, ECG-gated MRI provides information nearly comparable to that of radionuclide technique in the evaluation of left ventricular function and wall motion. Therefore, we regard gated MRI as effective in evaluating various aspects of cardiovascular diseases.

Adult↗