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H Kamiyama

Publications and source records attributed to H Kamiyama.

At least 19 recordsLinked to original sources
PubMed1992

Distal aneurysms of the superior cerebellar artery and posterior inferior cerebellar artery feeding an associated arteriovenous malformation: case report.

The authors report a case of two distal aneurysms of the cerebellar arteries, one arising from the vermian branch of the posterior inferior cerebellar artery, the other arising from the hemispheric branch of the superior cerebellar artery, and both feeding an associated arteriovenous malformation (AVM). The aneurysm of the distal posterior inferior cerebellar artery was considered the source of a cerebellar hemorrhage because of the location of a hematoma in the cerebellar vermis. The life-threatening hematoma was evacuated in an emergency operation 6 hours after the acute onset of symptoms. The cerebellar aneurysms and the AVM were clipped or extirpated successfully after the patient's condition improved. The association of two rare types of aneurysms with an AVM strongly supports the theory that increased hemodynamic stress derived from the AVM plays an important role in aneurysm formation. The authors think that one should operate on the symptomatic lesion first or both the aneurysm and the AVM in the same operative procedure.

Aged↗
PubMed1992

"True" posterior communicating artery aneurysm--report of two cases.

Two cases of true posterior communicating artery (PcomA) aneurysm are described. A 27-year-old female with subarachnoid hemorrhage demonstrated a saccular aneurysm at the branch of the anterior choroidal artery from the PcomA. The aneurysm was successfully clipped. A 23-year-old male involved in an automobile accident suffered from traumatic subarachnoid hemorrhage. Computed tomography 10 weeks after head injury demonstrated a high-density mass in the right parasellar region, diagnosed as a traumatic aneurysm arising from the PcomA. The aneurysm was successfully clipped. Histological examination demonstrated findings consistent with true aneurysm.

Accidents, Traffic↗
PubMed1992

Cavernous angioma of the cerebellum and cerebellar atrophy--case report.

A cavernous angioma of the cerebellum occurred in a 55-year-old female presenting with a 3-year history of slowly progressive cerebellar signs and symptoms. Computed tomography and magnetic resonance imaging revealed a lesion in the left cerebellar nuclei and atrophic change of the affected cerebellar hemisphere. The final diagnosis was made at operation. The cerebellar nuclei and white matter were probably affected by the slowly expanding lesion, with repeated hemorrhage leading to degeneration of the afferent and efferent fibers, and subsequent atrophy of the affected cerebellar hemisphere.

Atrophy↗
PubMed1992

Magnetic resonance findings in spontaneous dissection of the cervical internal carotid artery--case report.

The magnetic resonance (MR) appearance of a spontaneous dissection of the cervical internal carotid artery (ICA) in a 53-year-old male is described. Cerebral angiograms demonstrated a long-segment stenosis of the left cervical ICA beginning above the common carotid bifurcation and extending to the skull base ("string sign"). T1-, T2-, and proton density-weighted MR images of the upper neck revealed a high-intensity crescent mass expanding the arterial wall and narrowing the arterial lumen of the left ICA. This high-intensity mass was considered to represent the mural hematoma of the involved ICA. Gradual improvement of the dissection was confirmed by both angiography and MR imaging. Cerebral angiograms have shown pathognomonic findings such as double lumen and intimal flap in only some patients with ICA dissection. Our experience suggests that MR demonstration of the mural hematoma is specific and important for diagnosis and follow-up in cases of spontaneous dissection of the cervical ICA.

Aortic Dissection↗
PubMed1992

Menopause related changes of adrenocortical steroid production.

To elucidate changes of adrenocortical steroid production with age, reproductive age (n = 14), peri-menopausal (n = 12) and post-menopausal (n = 13) women were studied using basal hormone levels and the results of a rapid ACTH stimulation test. Peripheral serum levels of pregnenolone, 17 alpha-hydroxypregnenolone, 17 alpha-hydroxyprogesterone, dehydroepiandrosterone and androstenedione were measured by RIA. The basal levels of all steroids except pregnenolone decreased with age. A significant increase in the levels of all steroids after ACTH stimulation was observed in all subjects. Although, there was an age related decrease in the response of C19-steroids to ACTH, the response of pregnenolone and 17 alpha-hydroxyprogesterone to ACTH did not alter with age. The preserved response of 17 alpha-hydroxyprogesterone to ACTH in post-menopausal women suggests that 17 alpha-hydroxyprogesterone production plays a role in the age independency of cortisol. In the present paper, the changes in the capacity of the post-menopausal adrenal cortex to produce androgens and C21-steroids were demonstrated.

17-alpha-Hydroxypregnenolone↗
PubMed1992

[Clinical application of phase contrast angiography].

"Phase Contrast Angiography" is a new technique of Magnetic Resonance Angiography as reported by Dumoulin CL et al. Using this technique, we can obtain images of vessels (angiograms) without injection of contrast medium. We present the results of phase contrast angiography on cerebral and spinal vascular disease. We utilized the General Electric SIGNA, 1.5 tesla NMR. One hundred and ninety-one cases of cerebral and spinal vascular diseases were scanned using phase contrast angiography. Included were 90 cases of occlusive vascular disease, 16 cases of moyamoya disease, 39 cases of arteriovenous malformation, and 28 aneurysms. The phase contrast angiography uses flow encoding gradient pulses, which impart a velocity-dependent phase shift to the transverse magnetization of moving spins. The resulting image contains only information from the moving spins; while information from stationary tissue remains suppressed. In cases using 3-D angiogram, we made 32 images 6 degrees apart in their projection direction and displayed them on a video terminal. We were able to visualize occlusions of vessels, aneurysms, bypassed vessels, and abnormal vessels of arteriovenous malformations. Retrospective evaluation comparing phase contrast angiography with conventional angiography of the stenotic findings on the horizontal portion of middle cerebral arteries (64 vessels of 32 patients), resulted in a false positive ratio of 39.1%. We obtained clinically valuable results regarding the hydrodynamics of patients using "phase contrast angiography" non-invasively. These results reveal not only "anatomical" images of vessels, but also "functional" images, which are sensitive to the pattern of the blood flow. This study would strongly suggest that phase contrast angiography presents a valuable tool for the clinical diagnosis of cerebral and spinal vascular diseases.

Cerebral Angiography↗
PubMed1992

[Evaluation of cerebral blood circulation using fast magnetic resonance imaging (turbo-FLASH)].

In its initial stage of development, poor time resolution was supposed to be inevitable for magnetic resonance imaging (MRI). The development of the gradient echo technique, however, has made an opening for a breakthrough to a fast MRI technique. However, conventional gradient echo technique is not fast enough to disclose the cerebral blood circulation. A new technique (turbo-FLASH), which combines gradient echo and preparation pulse, has opened the door to a true dynamic (high time resolution) MRI. The authors performed a basic study of this new fast imaging technique (Turbo-FLASH) for the evaluation of cerebral blood circulation. Using this dynamic MRI, the conventional Gd-DTPA administration (0.1mmol/kg, intravenous manual administration) has produced sufficient contrast to reveal a difference of the extent of enhancement between normal gray matter and white matter. In patients of cerebral infarction, the infarcted brain does not show any significant increase of signal intensity after the administration of contrast medium, whereas the normal brain shows a sharp increase of signal intensity after the administration of contrast medium. Indeed, many puzzling questions remain to be solved for clinical application of this new dynamic MRI. For example, the optimal quantity of contrast medium and optimal parameters for this sequence (T1 weighted or T2 weighted?) are still unknown. But, in any case, this dynamic MRI is expected to be a clinically powerful tool for the evaluation of cerebral blood flow.

Brain↗
PubMed1992

[Cerebral blood flow reactivity to hyperventilation in children with spontaneous occlusion of the circle of willis (moyamoya disease)].

To elucidate the relationship between cerebral blood flow (CBF) after hyperventilation (HV) and the rebuild-up phenomenon on the encephaloelectrogram (EEG) in children with moyamoya disease, comparative study of CBF immediately after HV and CBF after administration of acetazolamide (Diamox) was examined. CBF was measured by means of single photon emission CT (SPECT) using the 133Xe inhalation method. The subjects were 11 children (21 hemispheres) with moyamoya disease who were divided into two groups as follows, 1) Bypass group; who underwent STA-MCA anastomosis with other synangiosis. 2) Non-Bypass group; who underwent only some synangiosis such as EDAS, EMAS, EMS. The summary of the results is shown below. Regional CBF (rCBF) after HV of the frontal lobes in the Non-Bypass group had an evident tendency to show low perfusion compared with CBF in other regions. The correlation between low perfusion area after HV, and areas where the increase of rCBF is less after administration of acetazolamide became clear. The strongest relation was observed between low perfusion after HV and re-build-up phenomenon on EEG. On the other hand, rCBF after HV of the frontal lobes in the Bypass group had, compared with other regions, no tendency to show low perfusion. From this study and our previous reports, it is assumed that there is some hemodynamic insufficiency in the frontal lobes of the Non-Bypass group. The reason why the reduction of rCBF was less after HV especially in the frontal lobes of the Bypass group is still unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗
PubMed1992

[Changes in steroid enzyme activities with age in human ovary].

It is well documented that sex hormone secretion decreases as age advances. In this study, 17 alpha-hydroxylase (17hy), 20 alpha(beta)-hydroxy steroid dehydrogenase (20-HSD), C17-20 lyase, 17 beta-hydroxy steroid dehydrogenase (17 beta-HSD) and aromatase activities in ovarian tissues were examined in order to study the changes in steroid metabolism in human ovary with age. Tissues were obtained from women aged 30-81 years who had undergone gynecological laparotomy. Enzyme activities were measured by the conversion of 14C-labeled progesterone, 17 alpha-hydroxy progesterone and androstenedione to amounts of corresponding labeled products. Remarkable reduction of C17-20 lyase and 17hy activities were noticed in the ovaries obtained from the women in the premenopausal stage when the activities were compared with those from reproduct women. However, the activities of aromatase, 17 beta-HSD and 20-HSD were not changed. Further, a decrease of 17hy activities was observed in the ovaries obtained from menopausal women. Aromatase activity was also reduced at this stage while the 17 beta-HSD and 20-HSD remained unchanged. In addition, the formation of 17 alpha, 20 beta-OH-P4 from 17P4 was first demonstrated indicating that activity of 20 beta-HSD in postmenopausal ovary and found to be localized in the microsomal fraction. These result indicated that the changes of ovarian steroid enzyme activities with age were characterized by a striking reduction in C17-20 lyase and 17hy activities while 17 beta-HSD and 20-HSD activities were not impaired. Aromatase activity was found to be decreased in ovaries at menopause.

17-Hydroxysteroid Dehydrogenases↗
PubMed1991

Proximal clipping and bypass between bilateral vertebral arteries using a radial arterial graft for the treatment of a dissecting aneurysm of the vertebral artery.

Proximal clipping has been performed recently as the main surgical treatment for a dissecting aneurysm of the vertebral artery. When there is a contralateral vertebral artery of a smaller size with arteriosclerotic changes, some form of bypass to prevent cerebellar and brain stem infarction is needed in addition to proximal clipping. We treated a 50-year-old man with a ruptured dissecting aneurysm of the left vertebral artery and stenosis at the V3 segment of the right vertebral artery. The caliber of the right vertebral artery was smaller than the left. After an anastomosis between bilateral vertebral arteries using a radial arterial graft, dissecting aneurysm was clipped at the proximal portion of the aneurysm.

Aortic Dissection↗
PubMed1991

Clinical application of proton magnetic resonance spectroscopy to cerebral ischemia.

Proton magnetic resonance spectroscopy (MRS) with the depth resolved surface coil spectroscopy technique and the 1331-2662 water suppression method was used to examine two cerebral ischemia patients and 10 normal volunteers. In all cases, N-acetyl-aspartate, creatine, phosphocreatine, and residual lipid were clearly observed. No lactic acid peak was observed in normal volunteers, but a large lactic acid peak appeared in the early stage of cerebral ischemia. This MRS abnormality was observed before abnormalities appeared in conventional imaging such as computed tomographic scanning and magnetic resonance imaging.

Adult↗
PubMed1991

Drug-induced hypotension SEP test and acetazolamide test using 133Xe SPECT in patients with occlusive carotid disease--selection of candidates for extracranial-intracranial bypass.

The correlation between the drug-induced hypotension somatosensory evoked potential (SEP) test and regional cerebral blood flow changes after acetazolamide administration was studied. Fourteen patients presenting with transient ischemic attack, reversible ischemic neurological deficits, or minor completed stroke were evaluated. All patients had no or only localized low-density areas on computed tomographic scans, and unilateral occlusion or severe stenosis of the internal carotid or middle cerebral artery on cerebral angiograms. The Diamox asymmetry enhancement (DAE) was studied to detect reduced cerebral perfusion reserve in the affected hemispheres. The DAE was 7.9 +/- 5.8% in seven patients positive in the SEP test, significantly higher than -1.5 +/- 2.9% in patients negative in the SEP test. Postoperative SEP tests were negative in all five patients who underwent extracranial-intracranial (EC-IC) bypass surgery, suggesting that the EC-IC bypass improved the cerebral perfusion reserve in the affected hemispheres. The DAE decreased significantly in four of these patients. This study disclosed a significant correlation between the drug-induced hypotension SEP test and DAE. These parameters are considered important for evaluating patients with hemodynamic compromise and/or suitable candidates for EC-IC bypass.

Acetazolamide↗
PubMed1991

[Unilateral development of moyamoya vessels after contralateral cervical internal carotid artery occlusion. Case report].

A 41-year-old female suffered transient ischemic attack. Cerebral angiography revealed occlusion of the left internal carotid artery at the cervical portion and collateral pathways consisting of transpial anastomosis and parenchymal anastomosis from the posterior circulation. Five years later, the second angiography was carried out. Left carotid angiography revealed appearance of transdural anastomosis from the middle meningeal artery and the anterior ethmoidal artery. Right carotid angiography revealed severe stenosis at the carotid fork with moyamoya vessels. Bilateral encephalomyo-arterio-synangiosis was performed for revascularization. Postoperative bilateral carotid angiograms revealed good neovascularization on both sides. In typical moyamoya disease, occlusive change of the carotid fork with moyamoya vessels appeared symmetrically and simultaneously on both sides. Although this case is not a typical moyamoya disease, its pathogenesis is quite similar to that of moyamoya disease.

Adult↗
PubMed1991

[Vertebral dissecting aneurysm treated with trapping and bilateral posterior inferior cerebellar artery side-to side anastomosis; case report].

A case is reported of ruptured dissecting aneurysm of the intracranial vertebral artery (VA) operated on with VA trapping and bilateral posterior inferior cerebellar artery (PICA) side-to-side anastomosis. A 42-year-old male suddenly developed severe headache and vomiting. On admission, 3 hours later, he was in a state of moderate confusion (Japan Coma Scale 3) and had neck stiffness. Computed tomography (CT) revealed diffuse subarachnoid hemorrhage, especially thick in the posterior fossa with right side dominance. Right vertebral angiography disclosed a fusiform dilatation with proximal narrowing of the right VA which originated just proximal to the VA-PICA junction. Lateral suboccipital craniectomy was undertaken with the patient in a left park bench position. Right VA was dilated and discolored black, and right PICA arose from the proximal portion of this aneurysmal dilatation. Since it was impossible to clip the VA distal to the PICA for the proximal clip-occlusion, the VA including the VA-PICA junction was trapped. Considering the risk of developing infarction at the PICA territory, bilateral PICA was anastomosed at their posterior medullary segment in a side-to-side fashion because the occipital artery (OA) had been cut at the skin incision and could not be used for the OA-PICA anastomosis. The postoperative course was benign, but a mild lateral medullary syndrome developed. CT revealed no abnormal low density area and left vertebral angiography demonstrated the patency of the bypass. Thereafter, the deficit subsided gradually and the patient was discharged. He is presently working without neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Multilocular encapsulated intracerebral hematoma; a case report].

Encapsulated intracerebral hematomas mimicking a brain tumor have been reported as a rare occurrence. An additional case with a characteristic feature found on computed tomography (CT), and a clinical course is described. CT scans revealed a high density mass with peripheral low density in the brain. A hematoma was successfully removed and found to have a thick and multilobular fibrous capsule associated with cavernous hemangioma. Repeated hemorrhage due to vascular malformation was considered to have contributed to the formation of the capsule. Increasing awareness of the possibility of an encapsulated intracerebral hematoma as a clinical and pathological entity, would enable us to make a correct diagnosis and to select proper treatment. A thorough survey of occult vascular malformation is necessary in surgery.

Adult↗
PubMed1991

[Longitudinal change of H-1 spectroscopy in cerebral infarction].

Longitudinal change of the proton spectroscopy was observed in 2 cases of cerebral infarction. Proton spectra was acquired utilizing stimulated echo acquisition mode (STEAM). In acute stage, the increase of lactic acid and decrease of N-acetyl-aspartic acid (NAA) was observed prior to the appearance of abnormality in imagings such as magnetic resonance imaging and computer tomography. The increase of lactic acid was observed in subacute stage and chronic stage (in severe case). The decrease of NAA persisted in chronic stage. The increase of lactic acid and decrease of NAA indicate a damage of the ischemic tissue. The degree of the decrease of the NAA seems to be a reasonable indicator of the viability of the damaged tissue. The proton spectroscopy is a powerful modality for the evaluation of the extent of tissue damage caused by the ischemic insult.

Aged↗
PubMed1991

[Three-dimensional MR brain image using volume rendering method].

3-dimensional image reconstructed from the data of computer tomography has provided useful informations for the pre-operative evaluation in the field of neurosurgery and plastic surgery. However CT has failed to visualized the 3-dimensional surface image of the central nervous system. On the other hand the progress of high-speed data acquisition technique and 3-dimensional fourier transformation has enabled the practical 3-dimensional image using magnetic resonance imager. However for the visualization of a pure surface image of the brain and spinal cord a sophisticated method and special image work station has been necessary. The authors describe a technique for the pure surface image of the brain and spinal cord using a normal mini-computer system and magnetic resonance imager. This image has a good correlation to the macroscopic anatomical brain surface (sulci and gyri).

Brain↗