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Biomedical subjects

T Kumazaki

Publications and source records attributed to T Kumazaki.

At least 91 records · Page 5Linked to original sources
PubMed1997

Arteriovenous malformation of the gallbladder.

Review of the literature shows no reports of vascular malformation of the gallbladder. Herein we report an unusual case of arteriovenous malformation of the gallbladder in a patient with hepatocellular carcinoma. The gallbladder lesion was found incidentally during abdominal angiography for the carcinoma. The angiographic features were specific, comprising dilated and tortuous feeding cystic arteries, a racemose vascular network, and early-filling cystic veins.

Adult↗
PubMed1997

Magnetization transfer imaging of bone marrow with and without fat suppression.

RATIONALE AND OBJECTIVES: To assess magnetization transfer (MT) ratios of bone marrow at magnetic resonance (MR) imaging performed with and without fat suppression. MATERIALS AND METHODS: The authors performed MR imaging in 30 regions of normal bone marrow in 10 subjects by using four types of gradient-echo sequences: a combination of MT and fat-suppression techniques, only the fat-suppression technique, only the MT technique, and without MT or fat-suppression techniques. MT ratios of marrow obtained with and without the fat-suppression technique were quantitatively compared. RESULTS: The average MT ratio of marrow with fat suppression was significantly higher than that without fat suppression (P < .01). CONCLUSION: Because bone marrow includes both water and fat, the MT ratio of marrow was underestimated when MT imaging was performed without fat suppression. A fat-suppression technique should be used.

Adipose Tissue↗
PubMed1997

K-space filter effect in three-dimensional contrast MR angiography.

PURPOSE: In three-dimensional (3-D) contrast MR angiography, temporal misregistration between the data acquisition period and the arrival of the contrast agent in the target vessels is thought to degrade the quality of the reconstructed images. The purpose of this study was to demonstrate and investigate this effect in phantom experiments. MATERIAL AND METHODS: MR images of a phantom tube were evaluated with flowing materials of water or Gd-DTPA solution by changing from water to Gd-DTPA solution halfway through the data acquisition period. RESULTS: While no signal could be acquired with a stream of water in the tube, a clear signal was obtained with a flow of Gd-DTPA solution. Blurring and ghost artifacts surrounding the tube along the phase-encoding direction were observed when the flowing material was changed from water to Gd-DTPA solution halfway through the data acquisition period. CONCLUSION: K-space filter effect occurs during 3-D contrast MR angiography owing to the transient passage of the contrast agent, and this effect causes spatial artifacts in the reconstructed images.

Artifacts↗
PubMed1997

The value of emergency CT studies in spontaneous rupture of hepatocellular carcinoma. Analysis for tumor protrusion and hemorrhagic ascites.

CT characteristics of spontaneous rupture of HCC (n = 13) were reviewed retrospectively, and the value of emergency CT studies in this disease was evaluated. Especially, tumor protrusion ratio (TPR) and ascitic CT numbers were measured to for comparison with the data for unruptured HCCs and ordinary (e.g. non hemorrhagic) ascites (n = 13). As a result, except for diffuse type HCCs, the TPR was significantly higher than for the unruptured HCCs. Nine cases had intraperitoneal HDAs, and the laterality of the HDAs corresponded with that of the ruptured tumors in 8 cases. Also, the ascitic CT numbers apart from the HDA were still higher than the ordinary ascites. Therefore, a high TPR, HDAs adjacent to the tumor, and elevated ascitic CT numbers are important CT manifestations indicating HCC rupture. Diffuse HCCs, however, require careful clinical evaluation.

Adult↗
PubMed1997

Normal contrast enhancement of extraocular muscles: fat-suppressed MR findings.

PURPOSE: To evaluate contrast enhancement of normal extraocular muscles in the orbit. METHODS: Noncontrast and contrast-enhanced T1-weighted images of the orbit were acquired using a fat-suppression MR technique in eight patients with no orbital disease. Contrast enhancement of 64 extraocular muscles was evaluated and compared with that of 16 temporal muscles. RESULTS: Compared with temporal muscles, all extraocular muscles markedly enhanced after administration of contrast material. CONCLUSIONS: Because normal extraocular muscles enhanced markedly with contrast material, more attention should be paid to these muscles when using contrast-enhanced, fat-suppressed T1-weighted MR imaging to evaluate pathologic conditions.

Adipose Tissue↗
PubMed1997

[Uterine cervical carcinoma after radiotherapy: comparison between MR imaging and histopathological findings].

The findings of MRI and pathologic investigation were correlated in curatively irradiated uterine cervical carcinoma. Four patients having residual carcinoma diagnosed by biopsy underwent hysterectomy. MRI demonstrated the mass lesion in one patient with pathologic confirmation of massive viable cancer cells (case I). Of the other three patients, MRI demonstrated normal configuration of the uterine cervix. Cervical signal intensity, however, varied. Hyperintensity was noted in an area of the posterior wall on T2WI in case 2. The anterior wall of the case 2 and the other two cases showed hypointensity. Cervical specimens with normal intensity showed only a small number of degenerated cancer cells. On the other hand, pathologic examination of the posterior wall of the case 2 revealed both cancer cells with varying degrees of degeneration and necrotic tissues. Degeneration of cancer cells was stronger in the superficial layer than the deeper layer. Fibrosis, hemorrhage, granulation and hyalinization were hypointense on T2WI. T2 elongation reflected not only the residual tumor but the post-irradiation changes. Post-irradiated cervix with normal intensity indicated that only a small number of degenerated cancer cells may persist even if the biopsy was positive. We conclude that MRI is useful in evaluating tumor response to radiotherapy.

Carcinoma, Mucoepidermoid↗
PubMed1997

[Evaluation of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral vasospasm].

We evaluated the usefulness of three-dimensional CT angiography (3D-CTA) for the diagnosis of cerebral vasospasm following subarachnoid hemorrhage (SAH). Eleven patients with SAH who were suspected of having cerebral vasospasm on the basis of their clinical symptoms were examined by 3D-CTA with a spiral CT scanner after an intravenous bolus administration of contrast medium. 3D-CTA revealed vasospastic changes of the cerebral vessels in eight patients. Conventional angiography was performed in six patients immediately after the 3D-CTA examination, and demonstrated the cerebral vasospasm. In eight patients, a second 3D-CTA was performed with the same technique one week after the first 3D-CTA examination. The second 3D-CTA showed the cerebral vessels without vasospastic change. In conclusion, 3D-CTA is a promising, minimally invasive strategy for the assessment of cerebral vasospasm.

Cerebral Angiography↗
PubMed1997

[Diagnostic imaging of "body packers"].

Drug smuggling by intra-abdominal concealment, so called "body packing," has recently increased, even in Japan. Because of fatal drug intoxication and other adverse side effects, it is important to make a radiological diagnosis of body packers as soon as possible. A retrospective analysis of the images of plain abdominal radiography, computed tomography (CT) and ultrasound (US) was performed in twenty-three body packers to evaluate the imaging characteristics of three drugs (cannabis, cocaine and heroin). Cannabis (16 patients) and cocaine (5 patients) packages were demonstrated as well-demarcated rectangular-shaped high-density shadows surrounded by gas halo ("double condom sign") in abdominal plain radiographs and CT. Heroin packages (2 patients) were demonstrated as obscure shadows and were difficult to identify on plain radiographs, because they resembled stool masses. US was performed in one cannabis patient because of the refusal of radiological examination, and packages were demonstrated as round echogenic structures with dorsal echo extinctions. In conclusion, abdominal plain radiography, CT and US represent valuable diagnostic modalities in the assessment of body packers.

Abdomen↗
PubMed1997

[The usefulness and the problems of attenuation correction using simultaneous transmission and emission data acquisition method: studies on normal volunteers and phantom].

Attenuation correction using simultaneous transmission data (TCT) and emission data (ECT) acquisition method was applied to 201Tl myocardial SPECT with ten normal adults and the phantom in order to validate the efficacy of attenuation correction using this method. Normal adults study demonstrated improved 201Tl accumulation to the septal wall and the posterior wall of the left ventricle and relative decreased activities in the lateral wall with attenuation correction (p < 0.05: paired t-test). The counts of the posterior wall were however, significantly higher than those of the anterior wall and the lateral wall (p < 0.05: unpaired t-test). Moreover, relative low uptake of the apex was enhanced using attenuation correction. Static phantom studies revealed the self scatter from high 201Tl uptake organs such as the liver and the stomach pushed up the activities in the septal wall and the posterior wall. Cardiac dynamic phantom studies showed partial volume effect due to cardiac motion contributed to under-correction of the apex, which might be overcome using gated SPECT. Although simultaneous TCT and ECT acquisition was conceived of the advantageous method for attenuation correction, miss-correction of the special myocardial segments should be taken into account in assessment of attenuation correction compensated images.

Adult↗
PubMed1997

[Proton MR spectroscopy of hyperplastic hematopoietic marrow in aplastic anemia].

The purpose of this study was to compare the findings of magnetic resonance (MR) spectroscopy of hyperplastic hematopoietic marrow with those of normal bone marrow. Twenty-four samples of normal marrow from eight control subjects and 19 samples of hyperplastic marrow in aplastic anemia were examined with a 1.5T MR unit. The former showed low intensity on opposed-phase T1-weighted images, while the latter showed high intensity on both fast STIR and opposed-phase T1-weighted images. MR spectroscopy quantitatively confirmed that the water: fat ratio was increased and the transverse relaxation time of water was changed in hyperplastic bone marrow, compared with normal bone marrow. In summary, MR imaging is able to detect hematopoietic regions among a wide range of bone marrow of aplastic anemia, while MR spectroscopy allowed us to quantitatively analyze the cell population of hyperplastic hematopoietic marrow in aplastic anemia.

Adolescent↗
PubMed1997

[Assessment of left ventricular systolic function derived from ECG-gated myocardial SPECT with 99mTc-tetrofosmin: automatic determination of LV epi- and endocardial surface].

Non-invasive assessment of ischemic heart disease requires information of both LV function and myocardial perfusion. Recently, ECG-gated myocardial SPECT with technetium-labeled radiopharma-ceuticals can provide both of them. Gated myocardial SPECT were performed in thirty-three patients with cardiac disease using a two-headed rotating gamma camera system (ADAC; VERTEX), 30-60 minutes after resting injection of 555-740 MBq of 99mTc-Tetrofosmin. Then, the SPECT data were used to determine the LV epi- and endocardial surface, and LV volume for measurement of LVEF was calculated automatically. This entire computational process required only 210 seconds per 16 frame study. Interobserver agreement of EF values obtained from gated SPECT was excellent (r = 0.996, n = 10, p < 0.01). LVEFs obtained from gated SPECT showed good correlation to those calculated from radionuclide ventriculography (MUGA) (r = 0.91, p < 0.01). In conclusion, this automatic method using gated myocardial SPECT data was considered to be useful for assessment of LV function with reproducibility.

Aged↗
PubMed1997

[Assessment of cerebral circulation using echo planar imaging--basic analysis in quantitating the mean transit time, cerebral blood flow, and cerebral blood volume].

The mean transit time (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) using echo planar imaging (EPI) in 22 aged volunteers were measured based on moment analysis and gamma variate method. The first peak of signal intensity curve (p delta R2.) and the area under the curve after the first peak (AUC) were calculated according to the height over area method, as a convenient quantification. Then, MTT, CBF, and CBV were compared with AUC/p delta R2, p delta R2, and AUC, respectively. There was a good correlation between each other parameter (r = 0.67 - 0.92, every p < 0.001). The slow upward slope and the low peak height, however, caused a larger error between each other parameter.

Blood Flow Velocity↗
PubMed1997

[Assessment of regional microcirculatory changes by EPI perfusion studies in patients with multiple lacunar infarction].

The aim of this report is to assess regional cerebral microcirculatory changes by EPI perfusion study in patients with multiple lacunar infarction(MLI). Especially, we focused on the parameter(rCBV, MTT, rCBF) changes in the white matter and on the relationship between these changes in the gray and white matter. Twenty MLI patients(mean age 72 +/- 15 years) and 10 age-similar normal controls (mean age 65 +/- 12 years) were examined. As a result, the MLI patients demonstrated an insignificant rCBF reduction due to the rCBV elevation in the gray matter and a moderate rCBF reduction with less rCBV elevation in the white matter. These results show a difference in the vascular reserve between the gray and white matter, and insufficiency of the vascular reserve in MLI's white matter.

Aged↗
PubMed1997

[Prediction of the myocardial contractility improvement on early stage after the revascularization using low-dose dobutamine stress 99mTc-MIBI gated SPECT].

For prediction of recovery of LV contractility, 99mTc-MIBI gated SPECT at rest and that with dobutamine (DOB) loading were performed in 15 patients with myocardial infarction (MI). Regional % uptake (regionalx100/maximal count), % wall thickening [%WT; (ES-ED)x100/ED maximal count], and delta %WT (%WT at DOB stress-%WT at rest) were calculated for each of 8 segments (seg.), including 34 MI out of total 120 seg., which derived from short axis LV count profile. These 34 seg. were divided into two groups, recontractile (18 seg.) and non-recontractile (16 seg.), whether improvement of the wall motion following the intervention (3-5 months) was observed by echocardiography. In the result, there were 7 recontractile seg. in 8 seg. with mildly reduced perfusion (> or = normal mean % uptake-2 S.D.), and there were 11 recontractile seg. in 26 seg. with severe reduced perfusion (< normal mean % uptake-2 S.D.). Moreover, in segments with severely reduced perfusion, there was no significant % uptake difference between recontractile and non-recontractile seg. However, delta %WT of recontractile group (11.1 +/- 4.8%) was significantly higher than that of non-recontractile group (5.7 +/- 2.9%) (p < 0.01). In conclusion, although the improvement of contractility on early stage after the revascularization was sometimes underestimated with only perfusion (% uptake), myocardial DOB response of %WT which were obtained by gated SPECT with MIBI would avoid the underestimation.

Angioplasty, Balloon, Coronary↗