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Biomedical subjects

M Ohkawa

Publications and source records attributed to M Ohkawa.

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

Use of fluid-attenuated inversion recovery (FLAIR) pulse sequences for differential diagnosis of hepatic hemangiomas and hepatic cysts.

Fluid-attenuated inversion recovery (FLAIR) imaging of hepatic hemangiomas (10 patients, 16 lesions) and hepatic cysts (8 patients, 10 lesions) was performed. All hemangiomas were hypointense on T1-weighted images and hyperintense on T2-weighted images. With Gd-DTPA (0.1 mmol/kg), all hemangiomas were enhanced but not all cysts. It was necessary to perform contrast enhanced imaging to differentiate hepatic hemangiomas from hepatic cysts. However, on FLAIR imaging, hepatic hemangiomas were strongly hyperintense and 9 of the 10 hepatic cysts were isointense. One of the hepatic cysts was slightly hyperintense. FLAIR images were useful in differential diagnosis of hepatic hemangiomas and hepatic cysts without using Gd-DTPA.

Cysts↗
PubMed1997

[131I SPECT-imaging with body outline using convenient lightweight source].

In order to make the body outline clearly in SPECT images, we devised a simple line source holder with the objectives to have a lightweight line source, to reduce the radiation exposure to the staff and to make the system readily available. This technique was applied to evaluate the localizing lesions in patients with radioiodine treatment of thyroid cancer. 131I-SPECT imaging with body outline was found to be effective in 86.7 percent (13/15) of the cases compared with planar imaging. Clinically, the results significantly helped in the discrimination between cervical lymph node metastasis and thyroid bed, and between mediastinal lymph node metastasis and bone metastasis. In the case of multiple lung metastasis demonstrating diffuse accumulation in the lung fields, 131I-SPECT imaging with body outline did not provide an increase in sensitivity compared with planar imaging. This method is easy to perform and it is considered to be useful for localization of abnormal accumulation, relative to the body outline.

Aged↗
PubMed1997

Intraarterial infusion of papaverine in experimental cerebral vasospasm.

PURPOSE: To determine the effectiveness of intraarterial infusion of papaverine hydrochloride (PPV) in an experimental model of cerebral vasospasm and to measure the mean blood flow velocity of the middle cerebral artery (MCA). METHODS: Seven Japanese monkeys were divided into three groups: those studied 3 days-after surgery (the third-day group, n = 3); those studied 7 days after surgery (the seventh-day group, n = 3); and a control group (n = 1). Vasospasm was induced in the experimental groups by placing a blood clot in the subarachnoid space around the top of the internal carotid siphon. PPV (5 mg/kg) was infused (over 60 minutes) into the internal carotid artery (ICA). The vascular diameters of the ICA and MCA were measured on angiograms before and after infusion. The mean blood flow velocity in the MCA was measured on transcranial Doppler sonograms before and 24 hours after infusion. After fixation, the MCA was dissected out, stained, and examined microscopically. RESULTS: After vasospasm induction, both arteries were narrowed more than 30% in the third-day group and more than 50% in the seventh-day group. After PPV infusion in both groups, vascular dilatation of about 20% was seen. The mean increase in blood flow velocity in the third-day group (30%) was smaller than in the seventh-day group (70%). The mean blood flow velocity in the MCA decreased by about 30% in both groups, but increased again after 24 hours nearly to the level before PPV infusion. The intimal layer was more corrugated in the seventh-day group, and hypertrophy in the smooth muscle layer was also seen. Clinical examination showed no neurologic deficit in the third-day group 24 hours after PPV infusion; neurologic deficits were observed in the seventh-day group. CONCLUSION: PPV infusion may be more effective in early stages of vasospasm when vascular walls have fewer histologic changes.

Animals↗
PubMed1997

Benign osteoblastoma of the temporal bone.

We report a case of benign osteoblastoma arising in the temporal bone of a 28-year-old woman. Plain radiography showed a mass with an amorphous calcified matrix and a thin radiolucent marginal zone. CT and MR imaging were useful in delineating the extent of the tumor, and angiography showed its hypervascularity. Preoperative transarterial embolization was effective in reducing bleeding during surgery.

Adult↗
PubMed1997

[Effect of glucose-insulin infusion on thallium-201 chloride tumor imaging].

Thallium-201 chloride (201Tl) kinetics, may be affected by serum insulin levels like potassium kinetics. The purpose of the present study was to use glucose and insulin to improve 201Tl accumulation in the tumor. The results showed that the tumor-to-normal tissue ratio after simultaneous injection of 201Tl, glucose and insulin was significantly higher than that after the injection of only 201Tl, and that a ring appearance seemed to occur after glucose and insulin injection. This preliminary study suggests that 201Tl accumulation in the tumor is enhanced by glucose and insulin administration.

Animals↗
PubMed1997

[Highly reproducible technique for the estimation of trabecular bone density: three slice method on peripheral quantitative CT].

The reproducibility of bone mineral density (BMD) measurements with peripheral quantitative CT has been limited by the repositioning error. In this study, 1 mm-step 3-slice scan data were used to compensate for this error in trabecular BMD of the distal radius. The assessment was based on the liner relations between the cross-sectional area and trabecular bone mineral content and trabecular area ratio, on the condition that the trabecular bone is defined by a BMD value. The estimated reproducible errors of less than 2% under clinical conditions indicate that the method is reliable for follow-up examination.

Adult↗
PubMed1997

[Effectiveness of percutaneous transluminal angioplasty and intra-arterial papaverine infusion for symptomatic vasospasm after subarachnoid hemorrhage].

PURPOSE: To evaluate the clinical effectiveness of PTA and/ or intra-arterial infusion of papaverine (PPV) for the treatment of symptomatic vasospasm after subarachnoid hemorrhage. MATERIALS AND METHODS: From September 1989 to March 1996, twenty patients with symptomatic vasospasm were treated by PTA and/or intra-arterial infusion of PPV. Nine of the patients were treated by only PTA, eight by only PPV infusion, and three by both PTA and PPV infusion. Early clinical results were evaluated within 48 hours after treatment. Changes in the mean flow velocity (MFV) of the M1 segment as determined by TCD before and after treatment were also evaluated. RESULTS: Six of the nine patients (66.7%) treated only by PTA, six of the eight patients (75%) treated only by PPV, and all three patients (100%) treated by both PTA and PPV infusion showed improvement of neurological deficits within 48 hours after treatments. CONCLUSION: PTA was effective for main trunk vasospasm, while PPV infusion was more effective for peripheral severe vasospasm in recovery from neurological deterioration after subarachnoid hemorrhage. Use of both treatments further increased the effectiveness.

Adult↗
PubMed1997

[Construction of pulmonary time-volume curve using MR: comparison with lung volume measurements using CT].

This study was conducted to investigate the effectiveness of dynamic pulmonary ventilation using MR and to compare it with lung volume measurements using CT. MR images during tidal breathing and CT images at resting expiratory level were obtained in 7 normal volunteers. The correlation between lung volume using CT and that using MR at resting expiratory level was significant (r = 0.993, p < 0.001). Pulmonary time-volume curves for each lobe were constructed by applying a Fourier series. The technique used in this study appears to be potentially useful to assess lobar lung function non-invasively and quantitatively.

Adult↗
PubMed1997

Technetium-99m-MIBI and thallium-201 scintigraphy of primary lung cancer.

UNLABELLED: We evaluated the usefulness of 99mTc-MIBI scintigraphy in primary lung cancer in comparison with 201Tl-chloride scintigraphy. METHODS: There were 45 patients with primary lung cancer. All patients underwent dual-isotope imaging with 201Tl-chloride and 99mTc-MIBI. Regions of interest were placed over the tumors (T) and contralateral normal lung tissue (N) on one coronal view in the SPECT, and T/N ratio and retention index were calculated. RESULTS: The positive rate was 98% in both the early and delayed images for 201Tl-chloride and 96% in the early and 89% in the delayed image for 99mTc-MIBI. Both early and delayed T/N ratios for 201Tl-chloride were higher than those for 99mTc-MIBI. There was no significant correlation between T/N ratio and histological type of tumor in both images. However, in both images, there was a tendency for the early and delayed ratios to increase as the tumor diameter became larger. The retention index of 201Tl-chloride was higher than that of 99mTc-MIBI. There were no significant differences in the retention index with respect to the histological type and tumor size. CONCLUSION: The results of this preliminary clinical study suggest that 99mTl-MIBI can depict primary lung cancer similar to 201Tl-chloride. However, T/N ratio and retention index of 99mTc-MIBI in the tumor areas are significantly lower compared with those of 201Tl-chloride.

Adult↗
PubMed1996

Effect of tris-(hydroxymethyl)-aminomethane on experimental focal cerebral ischemia.

Systemic and focal cerebral acidosis is considered deleterious to cell metabolism and neuronal recovery. We investigated the immediate effect of tris-(hydroxymethyl)-aminomethane (THAM), an alkalizing agent, on focal cerebral ischemia produced by occlusion of the left middle cerebral artery (MCA) in cats with systemic acidosis. Occlusion of MCA resulted in prompt decreases in local cerebral blood flow of the ipsilateral marginal and ectosylvian gyri from 47.7 ml/100 g per minute in control to 32.3 ml/100 g per minute and 8.3 ml/100 g per minute, respectively. In the control group, physiological saline was infused continuously and the treated group received 0.3 M THAM to normalize systemic and focal cerebral acidosis. There were no significant changes in the systemic arterial pressure, arterial PO2 and PCO2 throughout the experiments in the two groups. Arterial pH decreased from 7.42 to 7.30 in the control, while it remained normal during THAM treatment. Extracellular pH of the marginal gyrus (peri-infarct zone) decreased from 7.39 to 6.87 with 6 h ischemia in the control group. In THAM infusion, extracellular pH was kept between 7.26 and 7.29, which was significantly higher than the control group. THAM significantly decreased infarct volume and lactate and water contents of the gray matter in the marginal gyrus at 6 h after occlusion. It is concluded that THAM infusion immediately after ischemia onset is considered effective in improving acidosis at the site of ischemic penumbra and consequently reduces lactate production, brain edema, and infarct volume.

Acid-Base Equilibrium↗
PubMed1996

Accumulation of Tc-99m MIBI in breast lymphoma: comparison with Ga-67 citrate.

We report 2 cases of malignant lymphoma of the breast which were clearly shown on total body imaging as well as on SPECT with Ga-67 and Tc-99m MIBI. Tumor accumulation of Ga-67 was seen in all cases including a recurrent tumor. Ga-67 scintigraphy is useful for follow up in detecting relapse, as well as in predicting responses to therapy. Tc-99m MIBI was found to accumulate in the malignant lymphoma of the breast, and especially SPECT images of breast lesions provided better contrast than planar images, and Tc-99m MIBI SPECT could diagnose localization of the tumor because there was no uptake by the breast. But the Tc-99m MIBI accumulation of the tumor was lower than Ga-67.

Breast Neoplasms↗
PubMed1996

Regular and irregular dichotomies of bronchial branching in the human lung.

RATIONALE AND OBJECTIVES: Typical models of the human bronchial tree depict regular branching. However, some anatomic studies also have revealed irregular dichotomies in the human lung. We therefore studied the patterns of bronchial branching in the human lung. METHODS: We examined a normal right lung. Bronchial branchings were traced up to terminal bronchioles (TBs) in both regular and irregular dichotomies. RESULTS: In 256 TBs in peripheral regions, the number of branchings varied from 11 to 23; the largest number was found in the S10c of the basal segment, and the average was 15. In 354 TBs in hilar regions supplied by irregular dichotomies, the number of branchings ranged from 9 to 15, with the average being 10. In secondary pulmonary lobules, bronchioles supplying the secondary pulmonary lobules reached TBs in two or three divisions. CONCLUSION: Irregular dichotomies are too frequent to be neglected in the interpretation of radiologic and physiologic findings.

Aged↗
PubMed1996

Septal structure of incomplete interlobar fissures of the lung.

RATIONALE AND OBJECTIVES: Some septal structures have been observed in the areas of incomplete interlobar fissures (IIFs) in resected lungs. We describe the anatomy of IIFs with or without the presence of septal structures. METHODS: Twenty fused areas from 16 autopsy cases were examined histologically. Other septal structures outside the areas of IIFs also were examined. RESULTS: In 10 of the 20 fused areas, there was a mixture of septal structures with and without defects. In the remaining 10, there were no septal structures. The septal structures consisted of two inner layers from both lobes. Other septal structures examined were the same as ones observed in the IIFs. CONCLUSION: Linear shadows seen at interlobar fissures and on computed tomography scans do not necessarily depict the presence of complete interlobar fissures. The absence of linear shadows does not necessarily imply the absence of septal structures.

Bronchi↗
PubMed1996

Transvenous embolization of traumatic carotid cavernous fistula with mechanical detachable coils.

An attempt at transarterial balloon embolization of a traumatic carotid cavernous fistula was made but the carotid artery rent was too small for this approach. The patient was then treated by antegrade embolization through a superior ophthalmic vein using mechanical detachable coils. Successful obliteration of the fistula was achieved with preservation of the carotid artery. Transvenous embolization is an alternative technique to treat patients with traumatic carotid cavernous fistulas, especially when a transarterial approach has failed.

Adult↗
PubMed1996

Infected renal cystic mass associated with bacterial meningitis: a case report.

We report a case of an infected renal cystic mass associated with bacterial meningitis in a 70-year-old woman who had had poorly-controlled diabetes mellitus for approximately 30 years. She suffered from bacterial meningitis due to Klebsiella pneumoniae, which was successfully treated with antimicrobial chemotherapy for 1 month. Approximately 2 weeks later she developed left flank pain and a high fever. A CT scan and an ultrasonogram revealed a left renal cystic mass, which was considered to be an infected renal cyst. Turbid and thick fluid was obtained by percutaneous aspiration which contained numerous white blood cells. Culture of this fluid yielded K. pneumoniae. The bacterial meningitis was considered to be a secondary infection of the septicemia which resulted from the infected renal cystic mass.

Aged↗