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Biomedical subjects

M Iwase

Publications and source records attributed to M Iwase.

At least 217 records · Page 12Linked to original sources
PubMed1986

Parathyroid carcinoma visualized by gallium-67 citrate scintigraphy.

An abnormal uptake of [67Ga]citrate by a palpable neck tumor was observed in a patient with primary hyperparathyroidism. The pathological diagnosis of the surgically resected specimen was parathyroid carcinoma invading the thyroid. The uptake was negative in nine patients with parathyroid adenoma. These results suggest that 67Ga scintigraphy may be useful to differentiate parathyroid carcinoma from benign parathyroid tumor.

Adenoma↗
PubMed1985

Evaluation of left atrial rhythm with pulsed Doppler echocardiography.

To evaluate the origin of ectopic atrial rhythms, the beginning of atrioventricular inflow due to left and right atrial ejection was estimated using the pulsed Doppler combined with two-dimensional echocardiography. In ten normal controls, the beginning of transtricuspid flow due to atrial ejection preceded that of transmitral by 0 to 40 msec with an average of 22 msec. In contrast, the beginning of right atrial ejection flow lagged behind that of left atrial by 40 to 80 msec in case 1 and by 20 to 50 msec in case 2 of ectopic atrial rhythm. The significant delay of atrioventricular inflow due to right atrial ejection in these two patients strongly suggests that the ectopic atrial rhythm is of left atrial origin. The pulsed Doppler echocardiography is considered to be a useful clinical tool for noninvasive evaluation of the left atrial rhythm.

Adult↗
PubMed1985

Evaluation of myocardial involvement in Duchenne's progressive muscular dystrophy with thallium-201 myocardial perfusion imaging.

Myocardial involvement in progressive muscular dystrophy of the Duchenne type was evaluated in 19 patients using thallium-201 myocardial perfusion imaging. A qualitative analysis was performed from five projection images by three experienced physicians. Distinct perfusion defects were shown in 13 patients, especially in the LV posterolateral or posterior wall (11 patients). There was no significant relationship between the presence of perfusion defects and the skeletal muscle involvements or thoracic deformities assessed by transmission computed tomography. Extensive perfusion defects were shown in 2 patients who died of congestive heart failure 1 to 2 years after the scintigraphic study. Progression of the myocardial scintigraphic abnormalities were considered to be minimal in 7 of 9 patients who underwent two serial scintigraphic studies over 2 to 3 years. It was concluded that thallium myocardial perfusion imaging is a useful clinical technique to assess myocardial involvement in Duchenne's progressive muscular dystrophy.

Adolescent↗
PubMed1985

[Evaluation of the atrial contribution to ventricular filling in patients with DDD pacemakers].

To evaluate the usefulness of physiologic cardiac pacing, the trasmitral flow velocity was recorded using the pulsed Doppler method combined with 2-D echocardiography in 14 patients in whom a DDD pacemaker was implanted. DDD pacemakers were programmed to atrioventricular (AV) sequential pacing with AV intervals of 50, 100, 150, 200 and 250 msec, and VVI pacing modes at a heart rate of 70 bpm. The time-velocity integral (TVI) of the left ventricular (LV) inflow curve was obtained by digitizing the outline of the tracings and expressed in the percentage of that of AV sequential pacing with AV interval of 150 msec (the percent LV filling volume). The percent LV filling volume was 75% for 50 msec, 89% for 100 msec, 96% for 200 msec and 90% for 250 msec of an AV interval in AV sequential pacing. It was significantly smaller at AV intervals of 50, 100 and 250 msec than at an AV interval of 150 msec. It was significantly smaller (68%) in VVI pacing than at AV intervals of 100, 150, 200 and 250 msec in AV sequential pacing. The left atrial (LA) contribution to LV filling was assessed in terms of the fraction of TVI during LA contraction to that during total LV filling at the optimal AV interval (A/Fmax). The optimal AV interval was defined as the interval at which the maximum LV filling volume was achieved in individual patients. The A/Fmax showed a positive correlation with the percent increase of LV inflow volume, with conversion from VVI to AV sequential pacing with the optimal AV interval. It also showed a positive correlation with age. These results suggested that the LV inflow volume was greater in AV sequential pacing with the optimal AV interval than in VVI pacing, especially in patients with a large A/Fmax. In conclusion, pulsed Doppler echocardiography could be a useful, non-invasive technique to determine the indications for implanting a DDD pacemaker and the optimal AV interval in patients in whom DDD pacemakers are implanted.

Adult↗
PubMed1979

Application of magnification radiography to the biliary system.

Magnification radiography was applied for the diagnosis of the biliary tract diseases including cancer. Our X-ray unit was consisting of HITACHI DR-155-23 U-6M-55P and 0.1 mm focal-spot tube, FFD 80 cm giving a magnification of x2 with the conditions of 60 kVp, 20 mA, 0.8 sec. Intensifying screens such as Kyokko LH II (for a standard sized subject) or DuPont Q II (for an obese subject) were used in combination with Fuji RX films. We confirmed a high diagnostic value in revealing early lesions of this sytem. The skin dose test indicated that this technique was routinely applicable with safety for clinical use.

Biliary Tract↗
PubMedDate not supplied

Relationship between beat to beat interval and left ventricular function in patients with atrial fibrillation.

In atrial fibrillation, the relation between the rhythm and volume of the pulse has long been of interest. However, changes in preload in this condition have not been fully addressed since beat to beat measurement of filling volume have been difficult until recently. In the present study, we evaluated left ventricular outflow and inflow velocity using pulsed Doppler echocardiography and correlated these results with the R-R interval in the individual patient. The study population consisted of 12 patients with atrial fibrillation, aged 36 to 69 years (mean 54 years). The etiology of atrial fibrillation was idiopathic in 10 and 2 patients had dilated cardiomyopathy. Stroke and filling volume were calculated as a pruduct of the flow velocity integral of left ventricular outflow and inflow velocity, and the cross-sectional area of aortic and mitral annulus, respectively. In 10 patients with idiopathic atrial fibrillation, significant positive correlations were observed between the preceding R-R interval and both the stroke volume and the filling volume of the preceding beat when the R-R interval was shorter than 600 msec. Stroke volume and filling volume of the preceding beat were almost constant, independent of the preceding R-R interval when the preceding R-R interval was longer than 600 msec, the interval necessary for the completion of the preceding rapid filling. In the same preceding R-R interval, a larger stroke volume was observed in a shorter pre-preceding R-R interval. In 2 patients with dilated cardiomyopathy no relationship could be observed between the preceding R-R interval and the filling volume of the preceding beat or the stroke volume. In patients with a normally functioning left ventricle (idiopathic atrial fibrillation), reduced cycle length and filling volume in the preceding cardiac cycle appear to be the underlying cause of the regulation of stroke volume, dependent on Starling's law. However, in patients with dilated cardiomyopathy no significant correlation was observed between the preceding R-R interval and both the filling volume of the preceding beat and the stroke volume. In these patients the left ventricle may have limited contractile reserve and altered diastolic re-coil forces possibly due to degenerative changes of myocardium. Pulsed Doppler echocardiography provides a non-invasive method of evaluating the instantaneous changes in left ventricular flow dynamics caused by atrial fibrillation and understanding its fundamental mechanism.

Adult↗