PubMed Health⌕ Search

Biomedical subjects

Akira Uchino

Publications and source records attributed to Akira Uchino.

At least 19 recordsLinked to original sources
PubMed2006

Clinicoradiological factors influencing the reversibility of posterior reversible encephalopathy syndrome: a multicenter study.

PURPOSE: The aim of this retrospective study was to clarify the relation between the reversibility of posterior reversible encephalopathy syndrome (PRES) with three factors: the anatomical region of the brain involved, the background clinical cause, and the diffusion weighted image (DWI) intensity of PRES lesions. MATERIAL AND METHODS: This multicenter study, conducted by the PRES Study Group of the Neuroradiology Workshop, involved 52 cases from 28 institutions. Initial and follow-up magnetic resonance imaging were compared regarding the reversibility of PRES lesions according to anatomical location and clinical background. Initial DWI and apparent diffusion coefficient (ADC) maps were reviewed in 20 cases. RESULTS: Reversibility was significantly lower (P < 0.01) in the brain stem (44%) and deep white matter (47%) compared to the other cortical and subcortical areas (76%-91%). The reversibility was greater in the eclampsia subgroup followed by the hypertension and chemotherapy subgroups. DWI, even with ADC maps, had limitations in predicting the outcome of PRES lesions. CONCLUSION: The typical cortical and subcortical PRES lesions showed reversibility, whereas the brain stem and deep white matter lesions showed less reversibility. PRES due to eclampsia showed maximum reversibility compared to hypertension- and drug-related PRES. DWI, even with ADC maps, had limitations in predicting the course of PRES.

Adolescent↗
PubMed2006

Retrograde flow in the dural sinuses detected by three-dimensional time-of-flight MR angiography.

INTRODUCTION: Retrograde flow in the left dural sinuses is sometimes detected by three-dimensional time-of-flight (3D-TOF) magnetic resonance (MR) angiography. The purpose of this study was to evaluate the incidence of this phenomenon and its characteristic features on 3D-TOF MR angiograms. METHODS: We retrospectively reviewed cranial MR angiography images of 1,078 patients examined at our institution. All images were obtained by the 3D-TOF technique with one of two 1.5-T scanners. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed the source images, inferosuperior MIP images, and horizontal MIP images and identified retrograde flow in the dural sinuses. RESULTS: We found retrograde flow in the dural sinuses of 67 patients on the source images from 3D-TOF MR angiography; the incidence was 6.2%. In 47 of the 67 patients, retrograde flow was identified in the left inferior petrosal sinus, in 13, it was seen in the left sigmoid sinus, and in 6, it was seen in the left inferior petrosal and left sigmoid sinuses. The remaining patient had retrograde flow in the left inferior petrosal and left and right sigmoid sinuses. The mean age of the patients with retrograde flow was slightly greater than that of the patients without this phenomenon (70 years vs 63 years). CONCLUSION: Retrograde flow in the dural sinuses frequently occurs on the left side in middle-aged and elderly patients during 3D-TOF MR angiography performed with the patient in the supine position. This phenomenon should not be misdiagnosed as a dural arteriovenous fistula.

Adolescent↗
PubMed2006

A hyperdense artery sign and middle cerebral artery dissection.

We describe a rare case of spontaneous middle cerebral artery (MCA) dissection that caused cerebral infarction and subarachnoid hemorrhage (SAH), which also presented with a hyperdense artery sign. A hyperdense artery sign of the MCA in acute cerebral infarction strongly indicates thromboembolic MCA occlusion, which is often treated with thrombolytic therapy. However, thrombolytic therapy for intracranial artery dissections has both risks and benefits, due to the association of artery dissections with SAH. Therefore, it is important to keep in mind that an MCA dissection can also cause cerebral infarction with a hyperdense artery sign, particularly in young patients presenting with headache.

Adult↗
PubMed2006

Squamous cell carcinoma arising from Stensen's duct.

We report a case of squamous cell carcinoma presumably arising from the left Stensen's duct. The tumor was discovered during management of recurrent left parotitis. Ultrasonography, computed tomography, and magnetic resonance imaging were useful for estimating the tumor and coexisting obstructive parotitis. Relapsing symptoms and the presence of parotitis seemed to be characteristic of tumors of Stensen's duct. For a mass accompanied by obstructive parotitis or relapsing parotitis without salivary calculus, a tumor of Stensen's duct should be included in the differential diagnosis.

Aged↗
PubMed2006

Anterior cerebral artery variations detected by MR angiography.

INTRODUCTION: From anatomical and angiographic studies, it is well known that there are several variations of the anterior cerebral artery (ACA). However, ACA variations have rarely been studied by magnetic resonance (MR) angiography. The purpose of this study was to investigate not only the type, location, configuration, and incidence of ACA variations, but also coexisting arterial pathology such as aneurysms detected by cranial MR angiography. METHODS: We retrospectively reviewed cranial MR angiography images of 891 patients at our institution. All images were obtained with one of two 1.5-T scanners using the three-dimensional time-of-flight technique. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed these horizontal MIP images, inferosuperior MIP images, and source images, and identified variations of the ACA. RESULTS: We found 50 instances (5.6%) of unilateral A1 segment aplasia, 27 (3.0%) of three A2 segments, 18 (2.0%) of an unpaired A2 segment, and 11 (1.2%) fenestrations of the A1 and/or A2 segment. Seven anterior communicating artery (ACoA) aneurysms and one ACA territory embolic infarction were found among the 50 patients with unilateral A1 segment aplasia. One ACoA aneurysm and one pericallosal infarction were found in the 27 patients with three A2 segments. Two distal ACA aneurysms were detected among the 18 patients with an unpaired A2 segment. No associated aneurysm was seen at the fenestrations. CONCLUSION: Although the clinical significance of ACA variations is usually minor, an associated aneurysm is found relatively frequently. Thus, recognizing ACA variations during the interpretation of cranial MR angiograms is important.

Adolescent↗
PubMed2006

Fenestration of the middle cerebral artery detected by MR angiography.

Unlike fenestration of the posterior cerebral arterial circulation, fenestration of the anterior cerebral arterial circulation has not been well described. We investigated the location and configuration of fenestration of the middle cerebral artery (MCA) detected by magnetic resonance (MR) angiography. We found 6 fenestrations of the MCA among cranial MR angiography images obtained from about 2,000 patients during the past 9 years at our institution using either of two 1.5T imagers. All images were obtained by the three-dimensional time-of-flight technique. Maximum-intensity projection images in the horizontal rotation view were displayed stereoscopically. All 6 fenestrations had small slit-like configurations, five located at the proximal M1 segment, the other, at the middle M1 segment. No associated aneurysm was found. Although MCA fenestration is extremely rare and cerebral artery fenestration usually has no clinical significance, an aneurysm can arise at the proximal end of the fenestration. Thus, recognizing MCA fenestration is important when interpreting cranial MR angiograms.

Adolescent↗
PubMed2005

Ipsilateral mamillary body atrophy after infarction of the posterior cerebral artery territory: MR imaging.

We describe herein magnetic resonance (MR) features of ipsilateral mamillary body atrophy after infarction of the posterior cerebral artery (PCA) territory. During the period May 2000 through July 2004, 13 patients with infarction of the PCA territory underwent cranial MR imaging in the chronic stage. Two 1.5-T scanners were used to obtain axial T1- and T2-weighted images with conventional spin-echo and fast spin-echo pulse sequences, respectively. The slice thickness was 6 mm, with a 2-mm interslice gap. Five of the 13 patients with PCA territory infarction had ipsilateral mamillary body atrophy. However, this asymmetry of the mamillary bodies was unclear in two of the five patients because of the thickness of the axial image slices. All five patients had a temporo-parieto-occipital infarction. The remaining eight patients had a parieto-occipital or an occipital infarction. Unilateral transneuronal mamillary body degeneration after infarction of the ipsilateral PCA territory including the posteromedial temporal lobe can be detected on conventional thick axial MR images.

Aged↗
PubMed2004

Symmetrical lesions of the middle cerebellar peduncle: MR imaging and differential diagnosis.

The purpose of this paper is to show several diseases that manifest symmetrical hyperintense lesions on the middle cerebellar peduncles, the largest connecting peduncles between the brainstem and the cerebellum, in conventional magnetic resonance (MR) images. We retrospectively reviewed cranial MR images obtained with 0.3-, 0.5-, 1.0-, and 1.5-Tesla scanners. We found symmetrical middle cerebellar peduncular lesions in patients with Wilson's disease; hepatic encephalopathy; extrapontine myelinolysis; acute disseminated encephalomyelitis; wallerian degeneration of the pontocerebellar tracts after either pontine infarction, pontine hemorrhage, or central pontine myelinolysis; leukodystrophy; olivopontocerebellar atrophy; and toluene abuse. Definitive diagnosis of these diseases can be made relatively easily on the basis of clinical data; however, examination of associated brainstem or supratentorial lesions in MR images is also important.

Adolescent↗
PubMed2004

Gyral abnormalities in the early stage of superior sagittal sinus thrombosis.

We report computed tomography (CT) features in a case of segmental thrombosis of the superior sagittal sinus. On the initial cranial CT scan, both frontal cortices showed focal areas of slightly increased attenuation. The lesions were isointense on magnetic resonance (MR) images no matter what pulse sequence was used, except on fluid-attenuated inversion recovery images, which showed curvilinear sulcal hyperintensity. On postcontrast T1-weighted images, curvilinearly enhancing structures were apparent in both frontal cortical sulci. No lesion appeared on follow-up CT or in MR images. We speculated that the areas of slightly increased attenuation in the cortices represented blood congestion in the cortical veins, venules and capillaries without serum leakage. Cranial CT images should be carefully interpreted to avoid overlooking subtle lesions.

Aged↗
PubMed2003

Report of fogging effect on fast FLAIR magnetic resonance images of cerebral infarctions.

We report a case of multiple small, presumably iatrogenic, cortical infarctions detected incidentally on magnetic resonance imaging (MRI) 5 days after preoperative cerebral angiography but not apparent 12 days after the angiography on noncontrast MRI including a fast fluid-attenuated inversion recovery (FLAIR) sequence. However, the lesions showed marked contrast enhancement with gadolinium on postcontrast T1-weighted images. Cortical laminar necrosis was observed on MRI 35 days after the initial angiographic study. This case shows that the MRI fogging effect may prevent detection of small cortical infarctions in the subacute stage even on fast FLAIR sequences. Postcontrast images should be studied to reduce diagnostic errors associated with this effect.

Aged↗
PubMed2003

Frontal lobe dysfunction caused by multiple lacunar infarction in community-dwelling elderly subjects.

We examined the factors that influence frontal lobe function among 119 community-dwelling elderly subjects, based on magnetic resonance imaging (MRI) and clinical findings. We interviewed the subjects, and conducted a neurological examination, electrocardiogram, blood test, brain MRI examination, and cognitive function tests. The modified Stroop test and a personal computer version of the Wisconsin Card Sorting Test (WCST) were used to evaluate frontal lobe function. The subjects with impaired frontal lobe function defined by the modified Stroop test were significantly older, had more lacunar infarcts, and had lower HDL cholesterol values based on a logistic regression model. Among the aged who appear apparently normal, multiple lacunar infarcts are the cause of latent frontal lobe dysfunction.

Age Factors↗
PubMed2003

Magnetic resonance imaging of sequelae of central pontine myelinolysis in chronic alcohol abusers.

Central pontine myelinolysis (CPM) is one of the serious neurological complications of alcoholism. This study evaluated magnetic resonance images of sequelae of CPM. Approximately 600 alcoholic patients were examined by a 1.0-T magnetic resonance imaging device, and 11 patients were retrospectively found to have a central pontine lesion, a presumed sequela of CPM. The lesions had various shapes and most were cavitary. In 3 of the 11 patients bilateral symmetrical oval lesions were faintly visible in the middle cerebellar peduncles. These middle cerebellar peduncular lesions were diagnosed as having Wallerian degeneration of the pontocerebellar tract secondary to CPM.

Adult↗
PubMed2003

Interferon therapy-responsive brain metabolic abnormalities in a case of adult-onset subacute sclerosing panencephalitis evaluated by 1H MRS analysis.

We describe a 22-year-old woman with an adult-onset, slowly progressive form of subacute sclerosing panencephalitis (SSPE), who was repeatedly evaluated by brain magnetic resonance spectroscopy (MRS). The brain lesion spectrum showed a decrease in N-acetylaspartate (NAA) resonance, an increase in inositol (Ins) resonance, and an unaltered choline signal. These findings suggest neuronal loss and reactive gliosis without inflammation, consistent with brain biopsy findings showing astrocytic proliferation unaccompanied by lymphocytic infiltrates. The unusually protracted clinical course might be attributable to an absence of inflammatory infiltrates in the brain. Intraventricular interferon injection plus oral inosine pranobex treatment produced a substantial improvement in the MRS findings, suggesting the validity of monitoring MRS in SSPE.

Adult↗
PubMed2003

Analysis of ischemic brain damage in cases of acute subdural hematomas.

BACKGROUND: Ischemic damage of the brain is one of the most important factors for the sequelae of acute subdural hematomas (ASDHs). However, ischemic damage is infrequently addressed in a systematic manner in the clinical setting. METHODS: The analysis of ischemic brain damage was performed based on serial computed tomography (CT) scans in 80 patients with traumatic ASDHs. Single photon emission computed tomography (SPECT) for regional blood flow and/or magnetic resonance imaging (MRI) were also performed. RESULTS: Follow-up CT scans showed ischemic brain damage in 19 patients and no significant damage in 35 patients. The remaining 26 patients progressively deteriorated to the point of brain death. The ischemic brain damage was seen most frequently in the territory of the anterior cerebral artery (13 cases), followed by the territory of the posterior cerebral artery (12 cases). The ischemic damages in the pallidum, the hypothalamus and the thalamus were demonstrated in 4, 8, and 4 cases, respectively. The ischemic damage in the underlying brain that was probably because of the direct compression of the hematoma was seen in only two cases. CONCLUSIONS: Most of the ischemic brain damage noted in this study was because of arterial compression secondary to the brain shift and brain herniation, rather than the direct effect of the hematoma upon the underlying brain. Ischemic brain damage adversely affects outcome morbidity, and the difficulty in preventing ischemic damage in cases with marked brain shift leads to poor outcome in patients with ASDHs.

Adolescent↗
PubMed2003

Ventricular diverticula in obstructive hydrocephalus secondary to tumor growth.

OBJECTIVE: The association of ventricular diverticula with intra- and paraventricular tumors causing obstructive hydrocephalus has rarely been reported. METHODS: Records and imaging findings for 57 patients with obstructive hydrocephalus caused by tumors who were treated at our institution were reviewed for the presence of ventricular diverticula. For the anatomic study of ventricular diverticula, data were collected from five cadaveric heads. RESULTS: Ventricular diverticula were identified on magnetic resonance imaging scans in five cases. Diverticula were similarly located in the quadrigeminal cistern but originated from the medial wall of the atrium of the lateral ventricle in three cases and from the superior portion of the fourth ventricle in two cases. Regression of diverticula occurred in all cases after either insertion of a shunt or removal of the obstructing tumor. The cadaveric study suggested that the choroidal fissure and the rostral portion of the superior medullary velum might be the origins of diverticula from the atrium and from the superior portion of the fourth ventricle, respectively. CONCLUSION: Ventricular diverticula should be distinguished from other cystic lesions in the quadrigeminal region. Detection of an ostium of a diverticulum or communication between the cyst and the ventricular system is important for diagnosis.

Adolescent↗