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H Atsumi

Publications and source records attributed to H Atsumi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Iodine-123-BMIPP imaging in unstable angina: a guide for interventional strategy.

UNLABELLED: The aim of this study was to clarify the clinical implications of decreased myocardial uptakes of 123I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) in patients with unstable angina. METHODS: Fatty acid metabolic imaging with 123I-BMIPP was performed in 20 patients with unstable angina during the pain-free state. Regional uptakes of 123I-BMIPP were scored semiquantitatively, and clinical characteristics and angiographic findings were compared between the patients with the normal and abnormal 123I-BMIPP images. RESULTS: There were 9 patients with normal and 11 patients with abnormal 123I-BMIPP images. Severe coronary stenosis exceeding 90% (91% compared with 44%, p < 0.05) and 99% (82% compared with 0%, p < 0.01) and collateral opacification (36% compared with 0%, p < 0.05) were more frequently observed in patients with abnormal 123I-BMIPP images than in those with normal images. Percutaneous transluminal coronary angioplasty or coronary artery bypass grafting was performed in 22% of patients with normal 123I-BMIPP images and in 82% of patients with abnormal 123I-BMIPP images (p < 0.01). CONCLUSION: Fatty acid metabolic imaging with 123I-BMIPP can determine the functional severity of coronary artery disease and is helpful for a clinical judgment in interventional treatment.

Aged↗
PubMed1996

Multi-modal volume registration by maximization of mutual information.

A new information-theoretic approach is presented for finding the registration of volumetric medical images of differing modalities. Registration is achieved by adjustment of the relative position and orientation until the mutual information between the images is maximized. In our derivation of the registration procedure, few assumptions are made about the nature of the imaging process. As a result the algorithms are quite general and can foreseeably be used with a wide variety of imaging devices. This approach works directly with image data; no pre-processing or segmentation is required. This technique is, however, more flexible and robust than other intensity-based techniques like correlation. Additionally, it has an efficient implementation that is based on stochastic approximation. Experiments are presented that demonstrate the approach registering magnetic resonance (MR) images with computed tomography (CT) images, and with positron-emission tomography (PET) images. Surgical applications of the registration method are described.

Brain↗
PubMed1996

Fatty acid metabolic imaging with 123I-BMIPP for the diagnosis of coronary artery disease: application to patients with diabetes mellitus and hyperlipidaemia.

The aim of this study was to assess the relation of plasma substrate concentration to 123I-beta-methyliodophenyl-pentadecanoic acid (123I-BMIPP) kinetics in the myocardium and to test the application of 123I-BMIPP imaging to patients with diabetes mellitus (DM) and/or hyperlipidemia (HL). 123I-BMIPP imaging was performed on 78 patients with suspected coronary artery disease, 22 with HL, 11 with DM, 12 with HL and DM, and 33 with neither HL or DM. Significant coronary stenosis (defined as > or = 50% of luminal diameter) was documented in 49 patients. After an overnight fast, blood samples were drawn for blood glucose, insulin, cholesterol, triglycerides and free fatty acid levels. Then, 148 MBq 123I-BMIPP was injected intravenously and flushed rapidly with saline. Data were obtained for 60s in a standard anterior projection in list mode, at a rate of 1 frame per second. Myocardial single photon emission tomographic (SPET) images were obtained 20 min and 4 h post-injection. The myocardial uptake of 123I-BMIPP was calculated using the Ishii-MacIntyre method. Regional accumulation of 123I-BMIPP was scored semi-quantitatively from 0 (normal) to 4 (no activity), and the sum of regional scores in each patient was defined as the total defect score (TDS). Myocardial uptake and clearance of 123I-BMIPP had no relation to the levels of blood glucose, insulin, cholesterol, triglycerides or free fatty acids. Myocardial uptake and clearance of 123I-BMIPP, TDS and the sensitivity of detecting significant coronary stenosis were not significantly different between the four groups of patients. We conclude that 123I-BMIPP can be used to detect impaired fatty acid metabolism in patients with diabetes mellitus and/or hyperlipidaemia.

Biological Transport, Active↗
PubMed1996

Delayed metabolic recovery of hibernating myocardium after percutaneous transluminal coronary angioplasty: assessment with iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid imaging.

The time course of improvement in fatty acid metabolism after percutaneous transluminal coronary angioplasty (PTCA) was investigated using echocardiography and fatty acid metabolic imaging with iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) before, 1 week and 3 months after PTCA in 31 patients with angina pectoris. Decreased left ventricular wall motion before PTCA improved 1 week after PTCA in 13 of 31 patients. 123I-BMIPP uptake was reduced in these 13 patients before PTCA, and did not improve 1 week after PTCA. Decreased myocardial uptake of 123I-BMIPP improved 1 week after PTCA in eight of 23 patients (group A). Thirteen patients in whom 123I-BMIPP uptake had not improved 1 week after PTCA showed a delayed recovery of 3 months after PTCA (group B). All patients in groups A and B showed improvement in wall motion 1 week after PTCA. Patients in group B had a higher incidence of unstable angina (77% vs 25%, p < 0.01), 99% or 100% stenosis (62% vs 13%, p < 0.01) and collateral vessels (46% vs 13%, p < 0.05) than those in group A. Serial fatty acid metabolic imaging with 123I-BMIPP after PTCA showed delayed metabolic recovery after improvement in wall motion in 13 of 23 patients. The presence of severe myocardial ischemia before PTCA enhanced the chronological discrepancies between the recovery of wall motion and fatty acid metabolism.

Aged↗
PubMed1996

[Quantitative assessment of an increase of myocardial 99mTc-MIBI accumulation during exercise--usefulness of response rate].

The increase of myocardial 99mTc-MIBI accumulation during exercise was evaluated quantitatively, and the feasibility of response rate as a noninvasive marker of coronary stenosis was tested. Myocardial perfusion imaging with 99mTc-MIBI during exercise and at rest was performed in patients with suspected coronary artery disease. A dose of 296 MBq of 99mTc-MIBI was injected intravenously at maximal treadmill exercise, and myocardial image was obtained 90 min later (1st image). Then, 740 MBq of 99mTc-MIBI was administered at rest, and myocardial image was repeated (2nd image). These images were corrected for a decay and injected dose, and the 1st image was subtracted from the 2nd image to obtain the rest image. An increase of myocardial accumulation of 99mTc-MIBI during exercise was defined as (exercise image-rest image) x 100/rest image (response rate). A response rate of a patient with normal coronary artery was 102%, whereas a response rate in the area of severe coronary stenosis was 21% in a patients with angina pectoris. After successful PTCA to a stenosed coronary artery, a response rate increased to 75% in this patient. Coronary perfusion reserve during exercise can be assessed noninvasively by 99mTc-MIBI. Response rate of 99mTc-MIBI provides additional information to conventional perfusion imaging and may be a new marker of severity of coronary artery disease.

Biomarkers↗
PubMed1995

Error analysis of table look-up method for cerebral blood flow measurement by 123I-IMP brain SPECT: comparison with conventional microsphere model method.

While N-isopropyl-p-[123I]iodoamphetamine (IMP) is commonly used as a flow tracer, significant clearance from the brain causes underestimation of CBF as compared with true CBF when conventional microsphere model analysis is applied. We previously reported a simple "table look-up" method for CBF measurement using IMP taking into account this clearance effect. The method is based on a two-compartment model, the K1 (corresponding to CBF) and k2 constants being obtained from a table from the ratio of the 1st SPECT (40 min) to the 2nd SPECT (180 min) counts. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, this approach was compared with conventional microsphere model analysis. For 30 subjects, the latter method entailed 8 min continuous arterial blood sampling after IMP infusion and the use of SPECT data at the end of this period, calibrated by a count ratio of 8 min/40 min planar images of whole brains. A good correlation was observed between the two methods (r = 0.88), but an overestimation of table look-up method CBF as compared with microsphere model CBF was observed contrary to theoretical predictions. Limitations in the estimation of SPECT data at 8 min, obtained with SPECT data at 40 min for calibration of the count ratio of 8 min/40 min whole brain planar images, might be responsible for this.

Amphetamines↗
PubMed1995

Error analysis of autoradiography method for measurement of cerebral blood flow by 123I-IMP brain SPECT: a comparison study with table look-up method and microsphere model method.

N-isopropyl-p-[123I]iodoamphetamine (IMP) has been commonly used as a cerebral blood flow tracer, but, significant clearance of IMP from the brain to the blood causes underestimation of cerebral blood flow (CBF) as compared with true CBF when the conventional microsphere model method is applied. Previously, we reported an "Autoradiography method" (ARG method) for measuring CBF by using IMP in which this clearance effect was corrected. This method was based on a two-compartment model (influx: K1, efflux: k2, K1/k2 = distribution volume of IMP (Vd)), the K1 (corresponding to CBF) being obtained form the table which showed a correlation between CBF and the brain counts of SPECT scan with a constant Vd value. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, the ARG method was compared with the table look-up method (TLU method) and the conventional microsphere model method (MS method) for 30 subjects. When the Vd value in the ARG method was assumed to be 50 ml/ml, CBF values obtained by the ARG method were correlated well with those obtained by the TLU method (Y = 1.04X-2.5; X: TLU, Y: ARG r = 0.97) and those obtained by the MS method (Y = 0.82X + 12.1; X: ARG, Y: MS, r = 0.84). But, when the Vd value was assumed to be more or less than 50 ml/ml, ARG method CBF were under- or overestimated compared with the TLU method. This indicated that the ARG method could be a reliable method for CBF measurement if the Vd was determined properly. CBF values obtained by the MS method were actually 13.2% higher than those obtained by the ARG method against previous studies. As reasons for this, errors in the effects of gray-white matter mixture in the ARG method and in estimation of the SPECT brain counts at 8 min in the MS method were considered.

Amphetamines↗
PubMed1995

Cerebral blood flow measurement with iodine-123-IMP SPECT, calibrated standard input function and venous blood sampling.

UNLABELLED: We previously reported simple methods for measuring cerebral blood flow (CBF) with 123l-labeled N-isopropyl-p-iodoamphetamine (IMP) and SPECT: table look-up method and autoradiography. With these methods, the arterial input function is obtained by calibrating the standard input function using one-point arterial blood sampling 10 min after IMP infusion. In this study, we sought to determine if these approaches can be as successful when used with venous blood sampling. METHODS: After IMP infusion, simultaneous arterial and venous blood samples were drawn from 30 subjects without heart or lung disease. RESULTS: The activity ratios of venous whole blood from the cubital vein to arterial blood were 0.75 +/- 0.09, 0.77 +/- 0.10, 0.78 +/- 0.03 and 0.83 +/- 0.11, respectively, at 10, 20, 30 and 50 min after IMP infusion. Venous blood activities were always 20% lower than the artery values over 50 min. When blood was sampled from the dorsal hand vein, however, the respective ratios were 0.92 +/- 0.03, 0.93 +/- 0.05, 0.97 +/- 0.04 and 0.98 +/- 0.08 after 10, 20, 30 and 50 min. Furthermore, when the palm was exposed to heat during the sampling period, blood activity levels increased to 0.92 +/- 0.04, 0.96 +/- 0.04, 0.99 +/- 0.05 and 0.98 +/- 0.03. Thus, venous blood activities were consistent with arterial activity, presumably because of the numerous arteriovenous anastomoses in the palm. Optimal times for venous blood sampling, with and without palm heating, were determined by error analysis to be 15 and 20 min, respectively, after IMP infusion. CONCLUSION: Venous blood sampling from the dorsal hand can be substituted for arterial blood sampling in IMP-CBF studies.

Amphetamines↗
PubMed1994

[Pseudocoarctation of the aorta associated with aortic valve regurgitation: a case report].

We reported a case of pseudocoarctation of the aorta associated with severe aortic regurgitation. A 63-year-old male admitted with congestive heart failure due to aortic regurgitation. The blood pressure was 170/60 mmHg in the right arm and the systolic pressure was 132 mmHg in the right leg. To and fro murmur and diastolic grade IV/VI blowing murmur was heard along the lower left sternal border. Aortogram demonstrated marked buckling of the descending aorta at the origin of the left subclavian artery without collateral circulation and bicuspid aortic valve with severe aortic regurgitation. His pressure gradient across the pseudocoarctation was 40 mmHg in the preoperative catheterization. We performed an aortic valve replacement (AVR) without further surgical treatment. The pressure gradient was reduced to 10 mmHg and his symptom improved after AVR. These results suggested that pseudocoarctation of the aorta may require no surgical treatment in some case associated with aortic valve regurgitation because of improvement of high pressure gradient across it by AVR alone.

Aortic Coarctation↗
PubMed1993

[Noninvasive assessment of left internal thoracic artery graft patency using transthoracic echocardiography].

To evaluate the utility of transthoracic echocardiography (TTE) for assessing the long-term patency of left internal thoracic artery (LITA) grafts, 36 patients who had coronary artery bypass grafting (CABG) were examined simultaneously for graft flow velocity by TTE and by graft angiogram. The flow velocity in the LITA graft was clearly visualized by TTE in 25 patients from the left supraclavicular echo view. On the basis of the angiogram, the sensitivity and specificity of TTE in the diagnosis of LITA graft patency were 71.4% and 100%, respectively. These 25 patients (mean follow-up time after CABG-29.6 months) were divided into 3 groups according to their preoperative diagnosis and the presence of grafts stenosis by angiogram as follows: APS(-), angina pectoris without graft stenosis in 15 cases; APS(+), angina pectoris with graft stenosis in 2 cases; OMI, old myocardial infarction without graft stenosis in 8 cases. The peak flow velocity D/S ratio and time velocity integral D/S ratio in the APS(-) group (2.48 +/- 0.73, 3.21 +/- 0.89) were significantly (p < 0.01) higher than those in the APS(+) group (0.30 +/- 0.23, 0.35 +/- 0.21) or in the OMI group (0.96 +/- 0.44, 0.87 +/- 0.51). Peak flow velocity D/(S+D) and time velocity integral D/(S+D) ratios in the APS(-) group (0.70 +/- 0.05, 0.75 +/- 0.06) were significantly (p < 0.01) higher than those in the APS(+) group (0.22 +/- 0.14, 0.25 +/- 0.11) or in the OMI group (0.46 +/- 0.17, 0.43 +/- 0.18).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Surgical treatment of cardiac myxomas].

Between April 1975 to March 1991, 17 patients (5 man and 12 women, mean age 49.8 years old) underwent surgical treatment for cardiac myxomas. Fifteen patients had left atrial myxomas, and the other 2 had the ventricular myxomas (left ventricular myxoma 1 and right ventricular myxoma 1). In cases with left atrial myxomas, the tumor was resected through the transatrial approach alone in 12 patients, and the left atriotomy was added in other 3. Left ventriculotomy was required to resect the left ventricular myxoma in addition to the atrial approach. Right ventricular myxoma, which attached the outflow tract, could be removed through the small right vertical ventriculotomy. All patients recovered well, and there was no recurrence in any patient during the follow-up period.

Adult↗
PubMed1992

Coronary artery bypass grafting in patients with depressed left ventricular function: operative results and long-term follow-up.

Nine consecutive patients with coronary artery disease who had a left ventricular ejection fraction (LVEF) of less than 0.4 and underwent coronary artery bypass grafting (CABG) at our institution were studied. All patients had angina pectoris and six of the nine patients (67%) had a history of congestive heart failure. The mean EF was 0.37 +/- 0.03 and the mean LV end-diastolic pressure was 10.1 +/- 4.9 mmHg. An average of 1.56 +/- 0.50 grafts per patient were placed and there was no operative death. The graft patency rate was 92.9% and the mean EF rose significantly from 0.37 to 0.53 after surgery (P less than 0.05). There was one late death, the 4-year actuarial survival rate being 88.9%. Of the eight long-term survivors, six (75%) were totally asymptomatic and only two had mild angina on exertion. This study confirmed that CABG for patients with depressed LV dysfunction can be performed safely with an acceptably low operative mortality, a significant improvement of LV function, and excellent long-term results.

Aged↗
PubMed1992

[Histological evidence of prolonged coronary artery spasm in a necropsy case of recurrent myocardial infarction].

A 69-year-old male had acute inferior infarction during an operation of an aneurysm of the abdominal aorta and died from multiple organ failure 3 weeks after the operation. His initial coronary angiogram (CAG) showed no significant stenosis, but repeated CAG showed that the patients had developed a prolonged spasm in the mid-portion of the right coronary artery. Histologically, we observed eccentric luminal narrowing with atheromatous plaque where the spasms had been demonstrated, and a "waving form" of elastic fibers accompanied by intimal thickening in the opposite site of the atheromatous plaque. These findings suggest that organic stenosis may be underestimated angiographically because of compensatory enlargement of the non-atheromatous site in some patients with coronary artery spasm, and prolonged spasms may augment organic stenosis by following intimal thickening.

Aged↗
PubMed1991

[Intracardiac repair in left ventricular rupture following mitral valve replacement].

Rupture of the left ventricle is one of the major lethal complications of mitral valve replacement. We have encountered 11 cases of this complication over a period of 19 years (1971, Apr.-1990, Mar.). Five of 8 cases of intraoperative rupture survived but no patient survived a delayed rupture. In the patients with intraoperative rupture external repair was performed in 6 cases, resulting in 3 survivors, two in type II and one in type I with formation of left ventricular false aneurysm. For selection of surgical treatment accurate recognition of types of rupture is important but the location and size of the endocardial and epicardial defects do not always correspond. Attempts to suture a ventricular rupture on the pressure-loaded beating heart were always unsuccessful and frequently extended the tear. Repair should be accomplished with aid of cardiopulmonary bypass on the decompressed and arrested heart. Recently, we chose internal repair with arrested heart in 2 cases of type I rupture, that is, reopening of the left atrial closure and repair from within the cardiac chamber with removal of the prosthetic valve. Both cases survived. In conclusion, we emphasized importance of intracardiac repair with removal of the replaced prosthetic valve in left ventricular rupture of type I and III following mitral valve replacement for better exposure, more secure repair, and prevention of injury to the circumflex artery.

Adult↗
PubMed1990

Sinus tachycardia masquerading as ventricular tachycardia.

We describe here a 87-year-old male who came to the emergency room with the chief complaints of dyspnea and chest pain. His electrocardiogram showed a wide QRS tachycardia with a heart rate of 140 beats/min, a left bundle branch block pattern and low voltage in leads I, aVL, V5 and V6. A long strip showed a premature ventricular complex, and the sinus beat just after the extrasystole showed P waves which were positive in leads I, II, III and a VF similar in shape to those in sinus rhythm. Therefore, a diagnosis of sinus tachycardia with tachycardia dependent left bundle branch block was made. The low voltage in the left lateral leads was ascribed to pneumothorax of the left lung. When a wide QRS tachycardia is encountered in an emergency situation, marked sinus tachycardia with coexistent bundle branch block or aberrant ventricular conduction should be taken into consideration.

Aged↗
PubMed1990

[Influence of ventriculoatrial conduction on hemodynamic consequences in patients with artificial pacing].

To assess the hemodynamic consequences associated with ventriculoatrial (VA) conduction following pacemaker implantation, 22 subjects with the sick sinus syndrome were studied using two-dimensional echocardiography (2DE) and Doppler techniques, including pulsed Doppler (PD). Pacemakers used were unipolar, programmable pulse generators which can operate in the DDD and VVI modes. A simultaneous strip chart recording of 2DE, phonocardiogram and ECG was obtained in each mode. Systolic time intervals (STI) and left ventricular diameters were measured using 2DE. Left ventricular ejection time (LVET) was determined from the aortic valve echo, which was the interval between the opening and closure of the cusp. Left ventricular pre-ejection period (LVEPEP) was the interval between the Q wave of the ECG and the opening of the aortic valve. Right ventricular (RV) STI were also measured using the pulmonary valve echo in a manner similar to that used with the aortic valve echo. Stroke volume and ejection fraction were calculated by conventional methodology. RVET was longer than LVET; RVPEP was shorter than LVPEP. These two STIs were shortened using an incremental pacing rate in each mode. Similarly, the stroke volume and ejection fraction decreased, depending on the pacing rate at a range of 50-110 b/min. RVET and LVET in DDD were longer than those in VVI. RVPEP and LVPEP in DDD were shorter than those in VVI. Stroke volume and ejection fraction in DDD were smaller than those in VVI. There was a significant difference (p less than 0.05) between DDD and VVI. These differences became significantly (p less than 0.01) greater between DDD without VA conduction and VVI with VA conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗