Biomedical subjects

K Machida

Publications and source records attributed to K Machida.

391 records · Page 22Linked to original sources

PubMedDate not supplied

Changes in plasma fatty acid profile in Japanese patients with chronic pancreatitis.

The serum zinc, prealbumin, retinol-binding protein and carotene concentrations and the plasma fatty acid composition were determined to assess the nutritional condition of 24 patients with chronic pancreatitis compared with that of 20 healthy controls. The daily food intake and faecal fat excretion of the two groups were also measured. In the chronic pancreatitis group, the calorie and fat intakes were significantly lower than those of the controls. Serum levels of zinc, prealbumin and carotene were also significantly lower than those of the controls. Percentages of plasma linoleic and arachidonic acids were low, while percentages of palmitoleic acid, eicosapentaenoic acid and docosahexaenoic acid were high. Fish oil intake correlated negatively with plasma linoleic acid concentration (P < 0.05). The above results indicate that the relatively high intake of fish oil and the relatively low intake of dietary fat in Japanese patients with chronic pancreatitis with a mild degree of steatorrhoea results in an abnormally low plasma level of linoleic acid.

Adult↗

PubMedDate not supplied

Quantitation of cerebral blood volume by 99mTc-DTPA-HSA SPECT.

The characteristics of technetium-99m diethylenetriaminepentaacetic acid human serum albumin (99mTc-DTPA-HSA) as an agent for quantitation of cerebral blood volume (CBV) were examined. The radioactivity after decay correction as a percentage of the activity at 10 minutes was 84.3 +/- 1.3% at 120 minutes after the injection of 99mTc-DTPA-HSA. Radioactivity was found exclusively in plasma, with little in blood cells. The blood retention of 99mTc-DTPA-HSA is sufficient, and its use in the quantitation of CBV omits the need for centrifugation of the blood sample. CBV quantified using the tracer and a SPECT system with a single-head rotating gamma camera was 4.09 +/- 0.60 ml/100 g brain, similar to values reported previously. Two serial SPECT scans provided similar images, and the CBV values determined by the two scans were closely correlated (p < 0.001). The high reproducibility suggests that the method may be used to monitor the cerebrovascular response to drugs. It was concluded that 99mTc-DTPA-HSA has useful properties for quantitative CBV measurement and that quantitation of CBV by 99mTc-DTPA-HSA SPECT is feasible using a system with a single-head rotating gamma camera.

Adult↗

PubMedDate not supplied

A new method for monitoring the cerebrovascular response to acetazolamide using 99mTc-DTPA-HSA.

We developed a new method for monitoring the cerebrovascular response to acetazolamide using technetium-99m diethylenetriaminepentaacetic acid human serum albumin (99mTc-DTPA-HSA). We infused 740 M Bq (20 mCi) of 99mTc-DTPA-HSA intravenously and carried out dynamic scanning of the anterior view of the head for 50 minutes. Ten minutes after the start of scanning, 1,000 mg of acetazolamide was injected intravenously. In three normal volunteers, the radioactivity in brain increased for an average of 8 minutes after the injection of acetazolamide and then remained relatively stable. The average of dilatation index [(peak count/the count just before acetazolamide injection-1)x 100] was 16.1. Our method enabled us to observe vasodilation caused by acetazolamide straight, and may be of value in assessing cerebral perfusion reserve easily and quantitatively.

Acetazolamide↗

PubMedDate not supplied

The optimum Butterworth-Wiener filter for I-123 IMP brain SPECT.

The optimum Butterworth-Wiener filter (BWF) for the preprocessing of N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) SPECT was determined by a simulation experiment. Sixty-four images of the brain phantom containing 14.8 MBq of I-123 IMP were collected with a gamma camera equipped with a slant hole collimator during a 360-degree rotation. The images were processed with 27 BWFs of different shapes, followed by SPECT image reconstruction and visual comparison. The optimum BWF had a cutoff frequency of 0.25/pixel, FWHM of four pixels, and constant of 0.05. The image quality was greatly affected by the cutoff frequency of BWF used for preprocessing.

Brain↗

PubMedDate not supplied

Bone scintigraphy in Maffucci syndrome.

Maffucci syndrome is a congenital, non-hereditary mesodermal dysplasia associated with multiple enchondromas and hemangiomas. The high risk of development of malignant tumors is well-known. A case of Maffucci syndrome in a 68-year-old man who suffered from multiple malignant degeneration and who was given a bone scintigraphic examination is reported with radiological and pathological findings. The scintigraphic findings are different for two histological different chondrosarcomatous lesions. It seems that uptake of Tc-99m MDP increases with the degree of calcification rather than whether the lesion is benign or malignant.

Aged↗

PubMedDate not supplied

The value of the modified high temporal resolution phase analysis for the detection of myocardial infarction.

Recently, cardiac nuclear medicine, especially gated RI cardiac blood pool scan has been improved remarkably, and now phase analysis has been introduced. We have developed a new modified phase image, with the objective of improving the time resolution, by displaying a special range of phase angles (about pi/3 radian) with 16 color scales, which correspond to the ventricles. Compared with the conventional method, the high resolution phase image improved the sensitivity of diagnosis of the region of myocardial infarction. The sensitivity of the modified phase image was 91% (10 cases our of 11), whereas that of the conventional method was 27% (3 cases out of 11).

Adult↗

PubMedDate not supplied

ECG-gated NMR-CT for cardiovascular disease.

We have developed an ECG-gated NMR-CT, and used it with 16 patients. The saturation recovery images are not able to separate heart muscle from the blood pool, but in inversion recovery images, heart muscle can be differentiated from the ventricles. The region of myocardial infarction is revealed as wall thinning and/or wall motion abnormality. From the two-gated inversion recovery images (the end-diastole and end-systole images) we obtained, we evaluated a wall motion abnormality in the left ventricle, and calculated the ejection fraction of the left ventricle. This information was then compared with the findings of a nuclear medicine study carried out one week interval and which included 10 of the 16 patients tested with the ECG-gated NMR-CT. The wall motions in both methods are well correlated, with the exception of the inferior wall. The values of the ejection fraction in the NMR image were moderately low, but two modalities showed a satisfactory correlation (r = 0.85).

Adult↗

PubMedDate not supplied

Functional imaging of thallium-201 myocardial washout and the clinical utility of this method.

In exercise testing with Thallium-201 myocardial scintiscan, we developed a quantitative myocardial Tl-201 washout image, a washout ratio and a washout index to detect ischemic segments. The washout value was measured with a pixel by pixel calculation between counts of the initial image and images that were delayed for three hours after the initial image. We compared the color displayed functional washout images with the original image in the detection of ischemic segments which had been confirmed by coronary angiography. A study of 22 patients showed 20 cases of coronary artery disease (with MI 8, but without MI 12) and two cases of normal control. The sensitivity for detection of a diseased vessel was 81% in the washout ratio imaging method and 79% in the washout index method, and both were superior to the sensitivity of the original image, which was 69%. As concerns MI cases, eight out of nine infarcted segments showed a lower washout, which represented partial redistribution on the delayed image. Six out of seven ischemic but not infarcted segments could be detected by the washout image, but only three were detected by the original image. These results indicate the washout image could provide not only transient ischemia but also additional ischemia of MI. We conclude that the washout image will be useful in producing a visual indication of ischemic areas.

Adult↗

PubMedDate not supplied

Measurement of cerebral blood flow with two-dimensional cine phase-contrast mR imaging: evaluation of normal subjects and patients with vertigo.

PURPOSE: The purpose of this study was to determine whether or not the vertebral flow of patients with vertigo and normal brain magnetic resonance (MR) images was decreased in comparison with normal controls. MATERIALS AND METHODS: Cerebral blood flow (CBF) was quantitatively measured by a two-dimensional phase contrast cine MR imaging technique in 24 normal controls (mean age, 38.6 years; range, 12-70) and 23 patients (mean age, 53.7 years; range, 19-76) with a 1.5 Tesla MR imaging unit. RESULTS: Inter- and intraobserver variation in blood flow measurements was small (r = 0.970, standard error of the estimate [SEE] = 2.9 ml, n = 80; r = 0.963, SEE = 4.6 ml, n = 40, respectively). In the normal group, mean summed vertebral flow (171 ml/min, SD = 40.6) was significantly less than mean summed carotid flow (523 ml/min, SD = 111). Right vertebral flow (80.2 ml/min, SD = 30.5) was less than left vertebral flow (91.2 ml/min, SD = 38.2), but the difference was not statistically significant (p < 0.05). In the 23 patients, although the summed vertebral flows of two patients (63.3, 88.8 ml/min) were significantly less than that of the normal group, mean summed vertebral flow (165 ml/min, SD = 59.1) showed no significant difference from that of the normal group (p < 0.05). CONCLUSIONS: In this study, the majority of patients had normal CBF. This method is clinically useful for estimating CBF.

Adolescent↗

PubMedDate not supplied

Assessment of the cerebrovascular response to acetazolamide using 99mTc-DTPA-HSA: methodological considerations.

We have reported methods of assessing the cerebrovascular response to acetazolamide using 99mTc-DTPA-HSA and their usefulness in evaluating cerebral hemodynamics. Several problems of this technique were investigated in 10 normal subjects. Following 99mTc-DTPA-HSA injection, dynamic imaging of the anterior head view was performed for 25 to 50 minutes, and 10 minutes after the beginning of imaging, 1,000 mg of acetazolamide was infused intravenously. Venous blood samples were obtained during the imaging period to estimate the blood retention of 99mTc-DTPA-HSA. Radioactivity in the head increased for about 10 minutes following acetazolamide infusion, then decreased slowly. The declining phase almost disappeared after correction for the blood clearance of 99mTc-DTPA-HSA, indicating stability of the vasodilatory effect of acetazolamide. Dilatation index, the percent increase in activity, was a little smaller after correction, but was closely correlated with the index without correction. There was a high correlation between dilatation indices obtained by two analyses, including ROI setting and visual determination of the peak, of the same data. In conclusion, neither blood clearance of 99mTc-DTPA-HSA nor subjective analysis considerably impairs the reliability of the dilatation index, and blood volume in the head from about 15 to 40 minutes after acetazolamide injection is stable and suitable for SPECT.

Acetazolamide↗

PubMedDate not supplied

SPECT measurements of cerebral blood volume before and after acetazolamide in occlusive cerebrovascular diseases.

Cerebral blood volume before and after acetazolamide was measured by SPECT to evaluate cerebral vasodilatory capacity in eight patients with cerebrovascular disease and five control subjects. Two SPECT measurements were performed serially, and acetazolamide was administered between them. The ratio of increase in hemispheric blood volume was calculated, and it was compared with the results of cerebral blood flow and cerebral blood volume measurements. A cerebral vasodilatory capacity map, the image after acetazolamide minus the baseline image, was also produced. Acetazolamide increased hemispheric blood volume in all unilateral carotid disease than in the uninvolved hemispheres of the patients and control subjects. The ratio of concordance with blood flow and blood volume measurements was approximated at 80%. Cerebral vasodilatory capacity mapping revealed three defects compatible with the clinical data. SPECT measurements of cerebral blood volume after acetazolamide can be performed following baseline SPECT with no additional radiotracer, and may be helpful to assess hemodynamic status.

Acetazolamide↗

PubMedDate not supplied

Localized reduction in 123I-MIBG accumulation in the lung.

A patient with old myocardial infarction underwent 123I-MIBG scintigraphy to evaluate the adrenergic nerve system in the heart following the treatment of pneumonia. Decreased accumulation of MIBG was observed in the right lower lung field, corresponding to the area affected by pneumonia, as well as in the left ventricle with myocardial infarction. 99mTc-MAA lung perfusion scan demonstrated hypoperfusion in the region of reduced MIBG uptake. Regional decrease in MIBG uptake in the lung is considered to suggest lung pathology, and lung perfusion scan is recommended to discriminate selective endothelial damage from loss of vascular bed.

3-Iodobenzylguanidine↗

PubMedDate not supplied

Delayed imaging of Tc-99m-DTPA-HSA SPECT in subacute cerebral infarction.

Cerebral blood volume measurement by Tc-99m-DTPA-HSA SPECT was performed in a patient with subacute cerebral infarction to evaluate compensatory vasodilatation. Additional delayed imaging revealed focal increased radioactivity that was not found on the early images, indicating leakage of radioactive agents due to blood-brain barrier breakdown. Delayed SPECT may be helpful to detect areas unsuitable for estimating regional blood volume.

Acute Disease↗