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Biomedical subjects

K Sadamoto

Publications and source records attributed to K Sadamoto.

At least 19 recordsLinked to original sources
PubMed2001

[Usefulness of time-resolved projection MRA on evaluation of hemodynamics in cerebral occlusive diseases].

The usefulness for evaluation of cerebral hemodynamics using time-resolved projection MRA was studied in normal volunteers and patients of cerebrovascular diseases. Six normal volunteers and ten patients with cerebrovascular occlusive diseases including 6 of IC occlusion and 4 of post EC/IC bypass surgery underwent time-resolved projection MRA on a 1.5 T clinical MRI system. Projection angiograms are acquired with 2 D-fast SPGR sequence with a time resolution of approximately one image per second, 40 images being acquired consecutively before and after bolus injection Gd-DTPA. And all images were calculated by complex subtraction from the background mask in a work station. In normal volunteers, the quality of images of time-resolved projection MRA was satisfactory. The arteries from internal carotid artery through M 2 segment of middle cerebral artery and all major venous systems were well portrayed. In 4 cases of IC occlusion who were assessed the collateral flow through the anterior communicating artery and posterior communicating artery, there were delayed to demonstrate the ipsilateral MCA. However, in 2 cases of IC occlusion that were assessed the collateral flow through leptomeningeal anastomosis, ipsilateral MCA and collateral circulation were not demonstrated. In all patients of post EC/IC bypass surgery, the patency of EC/IC bypass could be evaluated as properly with time-resolved projection MRA as 3 D-TOF MRA. Although the temporal and spatial resolutions are insufficient, time-resolved projection MRA was powerful non-invasive method to evaluate the cerebral hemodynamics via the basal communicating arteries in IC occlusion and identify the patency of EC/IC bypass.

Adult↗
PubMed2000

Transvenous embolization of carotid-cavernous sinus fistula associated with a primitive trigeminal artery--case report.

A 58-year-old female presented with right conjunctival chemosis and right abducens nerve paresis. Cerebral angiography demonstrated a right carotid-cavernous sinus fistula associated with persistent primitive trigeminal artery. The fistula was treated by introducing detachable coils through the transvenous approach, as the detachable balloon was not available. Follow-up angiography performed 14 days after the embolization revealed complete disappearance of the carotid-cavernous sinus fistula due to thrombosis, which was presumably accelerated by the coils. Transvenous coil embolization should be considered as an alternative treatment for high-flow carotid-cavernous sinus fistula, but only if transarterial balloon embolization is not successful or unavailable.

Arteries↗
PubMed2000

[Evaluation of hemodynamics in cerebral infarction using MRI with FAIR sequence].

In comparison with 99mTc-ECD SPECT, the usefulness for evaluation of cerebral blood flow by the perfusion images using MRI with FAIR sequence was studied in ischemic stroke patients. Among 27 cases, 15 patients showed lacunar infarctions and 12 patients showed cortical infarctions determined by T2 weighted MR images. FAIR images were obtained as single images at the slice position running through the basal ganglia or corona radiata. The inversion times(TI) were varied, ranging from 800 to 1,400 msec. In 15 patients without definite low perfusions in the SPECT study, FAIR images showed sequentially proxymal arterial branches in early phase and distal arterial branches or capillary beds in the cortical tissues in a late phase as the TI was elongated. Nine of the 12 patients with low cerebral perfusions in the SPECT study showed perfusion defects in FAIR imaging. Five of the 12 patients with a small low cerebral perfusion area in the SPECT study showed a delay of the depiction of cortical arteries along with TI elongation. In 3 patients, ischemic lesions demonstrated by the SPECT study was not shown in the MRI study because of motion artifacts. In conclusion, FAIR imagings are considered to be useful in the evaluation of cerebral flow dynamics in the ischemic stroke patients.

Aged↗
PubMed2000

[A case of adult moyamoya disease progressed after vascular reconstructive surgery].

We report an adult onset patient with moyamoya disease showing acute progress after contralateral vascular reconstructive surgery. A 47-year-old female developed cerebral infarction in the left corona radiata. A magnetic resonance (MR) angiography and a cerebral angiogram revealed severe stenosis extending from the terminal portion of left internal carotid artery (ICA) to the M1 portion. The right ICA showed slight stenosis. We performed direct bypass surgery (STA-MCA anastomosis) on the affected left side. MR angiography 1 month after surgery revealed the progressive stenosis of the C1 portion of the right ICA. While measurement of cerebral blood flow (CBF) showed a slight impairment of vascular reactivity to acetazolamide loading in the region of the right MCA, we continued without vascular reconstructive surgery for the right side because there was no ischemic attack. The patient had a transient sensory disturbance of the left upper extremity 16 months after surgery. MR angiography and a cerebral angiogram revealed more progressive stenosis extending from the right ICA to the M1 portion. CBF study showed a low CBF at rest and a negative response to acetazolamide loading in the region of the right MCA. Direct bypass surgery was performed on the right hemisphere. Follow-up study revealed an increment of rest CBF and improvement of vascular reactivity. We underlined the necessity for careful postoperation observation of progressive contralateral arterial stenosis using MR angiography and CBF study in adult onset patients with moyamoya disease.

Cerebral Angiography↗
PubMed1999

Diagnostic use of isotropic diffusion-weighted MRI in patients with ischaemic stroke: detection of the lesion responsible for the clinical deficit.

We examined the diagnostic use of isotropic diffusion-weighted (DW) MRI in 140 consecutive patients suspected of or diagnosed as having an ischaemic stroke. Isotropic DW imaging could demonstrate the lesion responsible for the clinical deficit in patients with multiple cerebral infarcts at an early stage, even small lesions without a perifocal oedema or mass effect. Accurate diagnosis by DW images may, however, be difficult about 2 weeks after the onset of stroke.

Adult↗
PubMed1999

Changes in visibility of intracranial arteries on MRA with normal ageing.

We investigated age-related changes in the visibility of intracranial arteries on magnetic resonance angiography (MRA) and the influence of risk factors for stroke. We studied 230 adult patients without specific neurological deficits. MRA was performed using the three-dimensional time-of-flight technique with a spoiled gradient-recalled acquisition sequence. We classified internal carotid artery (IC) and the horizontal (M1) and distal (beyond M2) middle cerebral segments into 4 grades. Linear regression revealed a significant negative relation between age and the quality of demonstration on MRA. For IC and M1, the score was significantly lower in subjects with risk factors than in those without. The distal MCA was poorly seen in patients without a history of hypertension or lacunar infarcts. A marked correlation was observed between visibility and age patients with no history of hypertension, diabetes mellitus and hyperlipidaemia. We suggest that atherosclerotic change and decline in flow velocity with normal ageing are factors leading to decreased visibility on MRA.

Adult↗
PubMed1999

[Changes in visualization of cerebral MR angiography with normal aging].

MR angiograms from 200 neurologically normal subjects aged 30 to 79 years were analyzed to assess the influence of aging and hypertension on the degree of the--visualization of the cerebral arteries. The degree of MR visualization of the cerebral arteries, including the IC, M 1, and distal MCA, was evaluated on a 4-degree scale. IC and M 1 differ in appearance. The MR gradings of each cerebral arteries showed a significant (p < 0.001) negative correlation with age. Hypertension, which is a risk factors for arteriosclerosis, significantly reduced MR grade. The degree of visualization of M 1 and the distal MCA decreased significantly with age in the normotensive group. Therefore, the decrease visualization of the cerebral arteries appears to involve not only cerebral arteriosclerosis but other factors associated with aging.

Aged↗
PubMed1999

Development of the local medical service network system. Integration of medical service with the network system between university hospital and other medical institutions.

Although every medical institution always make efforts to provide best services for the patients, it tends to be insufficient to send the patient's information and share them with other medical institutions. It is partly because in the Japanese medical care system there is no obligation to inform patients' medical information to other medical institutions. To provide effective and cost-effective medical service, we made a local network system between university hospital and other medical institutions. The system contributes to clarify the role of medical institutions and the continuity of medical service. For the next step, we must construct the home-care information service network towards the total service for the patients.

Community Networks↗
PubMed1998

Magnetic resonance angiography in patients with acute stroke treated by local thrombolysis.

Although magnetic resonance angiography (MRA) is accepted for showing chronic intracranial stenotic or occlusive lesions, the method has not been practically examined in patients with acute cerebral ischaemia. We carried out three-dimensional time-of-flight MRA in six patients with acute ischaemia treated by local thrombolysis, and compared the findings with those of digital subtraction angiography (DSA). In all patients, MRA before thrombolysis clearly demonstrated the occluded arteries, which corresponded precisely to those shown by DSA. In four patients with complete recanalisation of the occluded vessels after thrombolysis, the recanalisation could be demonstrated by postoperative MRA. In one patient with reocclusion of the recanalised artery, repeat MRA also demonstrated the reocclusion, confirmed by DSA. These results suggest that MRA may be helpful for noninvasive investigation before and after thrombolysis.

Adult↗
PubMed1997

[Functional MRI of higher brain function with gradient echo on clinical MR unit].

MR imaging of brain function has been successfully performed at 1.5 T clinical MR unit. In the early studies, functional MRI were performed with simple stimulation such as visual and motor. Recently, many investigators have attempted to demonstrate the specific brain localization of higher brain functions such as memory, imagination, language and so on. In this study, we attempted the functional MRI for motor and word imagination with gradient echo sequences on clinical MR unit. In our experiences, motor cortex was activated on motor imagination task and Broca area was activated on word imagination task, respectively. We demonstrated the higher brain functions were able to be demonstrated on clinical MR unit with gradient echo sequences.

Frontal Lobe↗
PubMed1996

Analysis of Ki-ras codon 12 mutations in the duodenal juice of patients with pancreatic cancer.

BACKGROUND & AIMS: Point mutations of the Ki-ras gene at codon 12 have been frequently identified in pure pancreatic juice of patients with pancreatic cancer in studies examining pancreatic cancer tissues. The aim of this study was to examine mutations of the Ki-ras codon 12 in the duodenal juice collected from patients with various pancreatic disorders. METHODS: The duodenal juice was collected through a Dreiling tube installed in the duodenum during a secretin test. Analysis of the Ki-ras mutations was performed using the enriched polymerase chain reaction--single-strand conformation polymorphism technique. RESULTS: Point mutations were detected in 12 of 19 patients with pancreatic cancer; of the 12 patients, 10 had ductal tubular adenocarcinoma and 2 intraductal papillary adenocarcinoma. Mutational patterns included GAT (n = 4), GTT (n = 3), CGT (n = 1), and double mutations of GTT and GAT (n = 3) and GAT and CGT (n = 1). In 41 patients with benign pancreatic disorders, a point mutation was detected in only 1 patient with chronic pancreatitis. CONCLUSIONS: Analysis of the Ki-ras codon 12 mutations in the duodenal juice is useful in the diagnosis of pancreatic cancer.

Base Sequence↗
PubMed1995

Grades of exophthalmos and thyrotropin-binding inhibitory immunoglobulin in patients with myasthenia gravis.

Exophthalmos and thyrotropin-inhibitory immunoglobulin (TBII) were examined in myasthenia gravis (MG) patients with normal thyroid function. Exophthalmos was found in 7 of 31 (22.6%) MG patients, and TBII was detected in 4 of 21 (19.0%) MG patients. The grades of exophthalmos did not decrease after extraocular muscle weakness was improved by treatment. Patients with MG whose diplopia was Tensilon unresponsive were only found among those with exophthalmos. TBII was more frequently detected in MG patients with exophthalmos than in those without. The present study revealed that exophthalmos is not rare in MG patients, even if they do not show any signs of Graves' disease other than exophthalmos and their thyroid functions are within the normal limit. The presence of TBII in MG patients may relate to the development of exophthalmos, and exophthalmos itself might enhance ocular symptoms of MG.

Adult↗
PubMed1995

Primary spinal chondrosarcoma localized in the cervical spinal canal and intervertebral foramen--case report.

A 48-year-old male presented with a very rare case of spinal chondrosarcoma localized in the cervical spinal canal and intervertebral foramen, but without marked destruction of the vertebral column. Spinal chondrosarcoma is characterized by radiological evidence of destruction of the surrounding bone structure and mottled calcification. Magnetic resonance imaging was useful in the diagnosis and determination of the extent of this spinal chondrosarcoma. However, preoperative differential diagnosis of the tumor was not possible based on neuroimaging evidence.

Cervical Vertebrae↗
PubMed1995

[Familial amyloidosis of the Finnish type (FAP) with extraocular muscle involvement].

Among 17 patients with amyloid polyneuropathy type IV in a Japanese family, we found a 72-year-old woman, who showed extraocular symptoms approximately 10 years after the onset of the disease. she developed weakness of the right facial muscles and dysarthria at age 57. She had atrophy and disturbance of movement of the tongue, along with difficulty in swallowing at age 62. At the age of 66, she felt diplopia when she looked toward the left, followed by difficulty of ocular movement. These manifestations progressed and at age 72, she was found to have mild ptopsis, mild to moderate disturbance of almost all extraocular muscles, moderate to severe disturbance of facial, masseter, pharyngeal, tongue and neck muscles. She also had slight weakness and atrophy of the limb and truncal muscles together with slight loss of pain and vibratory sensations in the distal parts of the limbs. FAP IV has sometimes been called cranial amyloidosis, but motor disturbance is limited to the middle and lower cranial nerve territories in the majority of the reported cases, and manifestations of the extraocular muscles are quite rare. According to the present investigation of the world literature, this is the second case of FAP IV with extraocular muscle involvement.

Aged↗
PubMed1993

Successful total removal of intramedullary hemangioblastoma from the medulla oblongata.

The case of a large solid hemangioblastoma embedded wholly in the medulla oblongata is reported. Preoperative magnetic resonance imaging provided precise indications of the anatomical location and radiologic features of the tumor, which facilitated its total removal by microsurgery. Short-latency somatosensory evoked potentials were monitored throughout the operation.

Adult↗
PubMed1992

Analysis of blood flow patterns in aortic aneurysm by cine magnetic resonance imaging--a review of case material.

Cine magnetic resonance imaging (MRI) (0.5-T) using rephased gradient echo technique was performed in 5 normal volunteers and 14 patients with aortic aneurysm to study the patterns of blood flow in aortic aneurysm. In the transaxial section, blood flow in normal aorta appeared as homogeneous and high intensity during systole. Blood flow in aneurysm appeared as inhomogeneous flow enhancement with flow void. In the sagittal scan, the homogeneous flow enhancement in normal aorta was also observed during systole, and its apex of flow enhancement was "taper." The blood flow patterns in aneurysm were classified as "irregular," "zonal," "eddy," and "obscure," depending on the contrast of flow enhancement and flow void. Their apexes were "taper" or "round." When the size of aneurysm became larger, the flow pattern in aneurysm tended to become "eddy" or "obscure" and the flow enhancement became "round." Though the exact mechanism of abnormal flow patterns in aneurysm remains to be determined, cine MRI gives helpful information in assessing blood flow dynamics in aneurysm.

Adult↗