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Yuji Numaguchi

Publications and source records attributed to Yuji Numaguchi.

15 recordsLinked to original sources
PubMed2005

Clinically silent choroid plexus cyst: evaluation by diffusion-weighted MRI.

We retrospectively reviewed diffusion-weighted magnetic resonance images of 57 patients with a choroid plexus cyst diagnosed by contrast-enhanced T1-weighted imaging. All the cysts appeared to represent incidental findings. Thirty-eight of 57 patients had bilateral cysts and 19 had unilateral ones. On diffusion-weighted images, 78 of 95 cysts showed homogeneously high signal intensity, 12 showed focal high signal areas, and 5 had no portion with a high signal. The apparent diffusion coefficient of the high signal areas in the cysts was (1.46+/-0.14) x10(-3) mm(2)/s, intermediate between the apparent diffusion coefficients of cerebrospinal fluid and cerebral white matter, (3.15+/-0.67) x10(-3) and (0.79+/-0.22) x10(-3) mm(2)/s, respectively. Pathological correlation was available in one case, showing high signal intensity areas in the glomera of the choroid plexuses in the lateral ventricles on diffusion-weighted images corresponding to gelatinous cysts with highly proteinaceous content.

Adult↗
PubMed2005

Intravertebral cleft sign on fat-suppressed contrast-enhanced MR: correlation with cement distribution pattern on percutaneous vertebroplasty.

RATIONALE AND OBJECTIVES: Filling intravertebral clefts during percutaneous vertebroplasty (PVP) is considered to be important for optimal pain control. It is often difficult to detect clefts on non-contrast MR and some fractures show a solid pattern distribution of injected cement without a cleft sign on non-contrast MR. In this study, we evaluated usefulness of fat-suppressed contrast-enhanced MR to predict a solid pattern distribution of injected cement on PVP. MATERIALS AND METHODS: Twenty-six patients with 35 vertebral compression fractures due to osteoporosis were studied. We performed sagittal T1-weighted, T2-weighted and fat-suppressed contrast-enhanced T1-weighted images prior to PVP. First we evaluated the presence of fluid-filled or gas-containing clefts on non-contrast MR. Next we evaluated contrast-enhanced MR of the same vertebrae for the presence of cleft-shaped unenhanced areas within the diffuse enhancement area. We correlated MR findings with cement distribution patterns of injected cement. RESULTS: Based on MR findings, 35 osteoporotic fractures were divided into 3 types. Type 1 (11 fractures, 31%): There were no clefts on non-contrast MR and no unenhanced areas on contrast-enhanced MR; Type 2 (13, 37%): There were no clefts on non-contrast MR but there were unenhanced areas on contrast-enhanced MR; Type 3 (13, 37%): There were clefts on non-contrast MR and unenhanced areas on contrast-enhanced MR. Of 35 osteoporotic fractures, thirteen vertebral fractures (37%) were noted to contain clefts on non-contrast MR, while 24 vertebral fractures (69%) contained unenhanced areas on contrast-enhanced MR. Cement distributed as a solid pattern within clefts or unenhanced areas in all fractures with them. CONCLUSION: Fat-suppressed contrast-enhanced MR is useful to predict a solid pattern distribution of injected cement prior to PVP.

Aged↗
PubMed2005

Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging.

OBJECTIVE: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b0 images obtained from DWI, as compared with gradient-echo (GRE) imaging. METHODS: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b0 images and GRE imaging. RESULTS: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b0 images to identification of hemorrhagic DAI lesions was inferior to that of GRE. CONCLUSION: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI.

Adolescent↗
PubMed2005

Percutaneous sacroplasty for hemorrhagic metastases from hepatocellular carcinoma.

Percutaneous injection of bone cement is a promising treatment for metastatic tumors. We present a case of hemorrhagic sacral metastases from hepatocellular carcinoma treated successfully by percutaneous sacroplasty with combined injections of bone cement and n-butyl cyanoacrylate resulting in pain relief.

Administration, Cutaneous↗
PubMed2003

Increase in vertebral body height after vertebroplasty.

BACKGROUND AND PURPOSE: During clinical work, we have seen increases in vertebral body height associated with vertebroplasty, but our literature search revealed no reports as to how often and to what degree those increases occur. The purpose of this study was to document the frequency and degree of changes in vertebral body height after vertebroplasty. METHODS: The heights of 85 vertebral bodies in 37 patients were measured before and after vertebroplasty. In addition, one adjacent vertebral body was measured in each patient as a control. Twenty-six patients had compression fractures in the thoracic spine, and 24 patients had compression fractures in the lumbar spine. Vertebroplasty was performed with a bilateral transpedicular approach by injecting polymethylmethacrylate, under biplane fluoroscopic control. Measurements were performed on preoperative MR images and on postoperative CT sagittal reformations. Anterior, central, and posterior vertebral body height measurements were obtained in the midsagittal plane. RESULTS: The average increase in vertebral body height was 2.5 mm anteriorly, 2.7 mm centrally, and 1.4 mm posteriorly. Thirteen of 85 treated vertebrae remained unchanged. All control vertebral bodies also remained unchanged. CONCLUSION: Vertebral body height often increases during vertebroplasty. The clinical significance of increasing vertebral body height is unknown.

Aged↗
PubMed2002

Secondary degeneration of the substantia nigra and corticospinal tract after hemorrhagic middle cerebral artery infarction: diffusion-weighted MR findings.

Middle cerebral artery (MCA) infarction involving the striatum can cause secondary degeneration of the substantia nigra and corticospinal tract. We present a patient with subacute hemorrhagic MCA infarction in whom diffusion-weighted MR images showed high signal intensity in the ipsilateral substantia nigra and corticospinal tract. A corresponding apparent diffusion coefficient map revealed a uniformly decreased signal in the same area. This represents secondary degeneration and should not be mistaken for other pathological conditions, such as a new infarction.

Aged↗
PubMed2002

Imaging findings in intracranial aspergillosis.

RATIONALE AND OBJECTIVES: The authors' purpose was to elucidate the various computed tomographic (CT) and magnetic resonance (MR) imaging findings in intracranial aspergillosis. MATERIALS AND METHODS: Retrospective analysis of cranial imaging findings was performed in eight proved cases of central nervous system aspergillosis. The patients ranged in age from 17 to 75 years. Four patients were immunocompromised, and four were immunocompetent. CT was performed in all eight patients, and MR imaging in five. RESULTS: Six patients (75%) had multiple lesions seen on the imaging studies, with a total of 27 focal brain lesions demonstrated. The lesions were most commonly seen in the cerebral hemispheres (n = 21), with lesser involvement of the basal ganglia (n = 2) and the posterior fossa (n = 4). Seven lesions were hemorrhagic on CT and/or MR images. There was a correlation between lesion size and hemorrhage, with hemorrhage more likely in larger lesions (>15 mm). At pathologic examination, foci of hemorrhage were noted within both infarcts and abscesses. Enhancement was noted in five lesions, four of which were confirmed abscesses. Contrast enhancement of the lesions was vague and week in immunocompromised patients but solid and strong in immunocompetent patients. There were 18 lesions without hemorrhage or enhancement; they were either infarcts or abscesses at pathologic examination. Some of these small nonhemorrhagic nonenhancing brain lesions in the subcortical white matter mimicked lacunar infarcts. CONCLUSION: Typical imaging findings of intracranial aspergillosis include multifocal lesions involving the cerebral hemispheres, with hemorrhage in approximately 25% of lesions. Lesional contrast enhancement tends to be stronger in immunocompetent hosts.

Adolescent↗
PubMed2002

Vasospasm model of a rabbit common carotid artery for endovascular research.

RATIONALE AND OBJECTIVES: Endovascular treatments such as balloon angioplasty and injection of vasodilators play an important role in cerebral vasospasm refractory to first-line therapies. Experimental studies with intracranial arteries of animals have some limitations, however, because in most cases endovascular devices are too large and inflexible to catheterize these arteries. The purpose of this study was to document the natural course of a vasospasm model using a rabbit common carotid artery. MATERIALS AND METHODS: The common carotid arteries of 24 New Zealand white rabbits were used. Autologous blood was placed around the isolated artery and kept in place with a silicone cuff. The time course of vasoconstriction after blood clot placement was examined with angiography and with histopathologic evaluation. RESULTS: Angiographic vasoconstriction was prominent on day 2, less obvious on day 9, and absent on day 30. At histopathologic evaluation, folding of the endothelial surface, corrugation of the internal elastic lamina, and thickening of the arterial wall were observed in the group with blood clot placements around the artery on day 2 and were nearly absent on day 30. CONCLUSION: This model may be used for the study of endovascular treatments of vasospasm.

Animals↗
PubMedDate not supplied

Diffusion-weighted MR imaging of posterior reversible leukoencephalopathy syndrome: a pictorial essay.

Posterior reversible leukoencephalopathy syndrome is characterized by reversible white matter lesions. However, ischemic injury with irreversible damage may occur. This pictorial essay illustrates MR features associated with posterior reversible leukoencephalopathy syndrome. We will emphasize the role of diffusion-weighted imaging for the discrimination of irreversible ischemic injury from reversible vasogenic edema.

Adult↗
PubMedDate not supplied

Sickle cell cerebrovascular disease: usual and unusual findings on MR imaging and MR angiography.

This paper demonstrates usual and unusual findings on MR imaging (MRI) including fluid-attenuated inversion recovery (FLAIR), diffusion- and perfusion-weighted image and MR angiography (MRA) in 30 patients with sickle cell cerebrovascular disease. This paper also illustrates the underlying pathophysiology of sickle cell cerebrovascular disease by using the cases with usual and unusual MR findings, including long-time follow-up cases during transfusion therapy. MRI and MRA are useful in defining the basis for stroke and assessing the effects of chronic transfusion therapy.

Adolescent↗
PubMedDate not supplied

CNS vasculitis and vasculopathy: efficacy and usefulness of diffusion-weighted echoplanar MR imaging.

This pictorial essay illustrates the usefulness of diffusion-weighted imaging (DWI) on various vasculitis or vasculopathies, including systemic lupus erythematosus (SLE), Behçet's disease, Churg-Strauss disease, primary angitis of the central nervous system (PACNS), giant cell arteritis, infectious vasculitis, sickle cell disease, drug-induced vasculopathy and hypertensive vasculopathy. DWI proves to detect small and active ischemic changes not visible on conventional MRI, and it clearly discriminates cytotoxic from vasogenic edema in patients with cerebral vasculitis or vasculopathy. DWI seems useful in assessing the treatment and patient outcome.

Adult↗
PubMedDate not supplied

Endovascular treatment using low-power ultraviolet laser for delayed vasospasm in the rabbit carotid artery model.

BACKGROUND AND PURPOSE: We previously reported that pretreatment with external ultraviolet (UV) irradiation at 325 nm before blood exposure prevented the development of chronic vasospasm in rabbit common carotid arteries. The purpose of this study was to investigate the preventive effect of endovascular UV light on vasospasm after blood immersion by using the same animal model. METHODS: The right common carotid arteries in 63 rabbits were enclosed in silicon cuffs on day 0. Sheaths were empty or filled with clotted blood. Thirty minutes after the placement of the sheaths, either alone or with blood, the common carotid arteries were subjected to UV or visible light (442 nm) irradiation via an endovascular approach at a fluence rate of 0.17 W/cm(2). The animals were killed on day 2, 9, or 30. Digital subtraction angiography was performed on days 0 and 2 and at the end point to evaluate the degree of vasospasm. RESULTS: UV treatment significantly prevented the development of vasospasm on day 2. On days 9 and 30, there were no significant differences between UV-treated animals and control animals. The preventive effect reached an approximate plateau with an irradiation time of 10 s. No severe vascular injury, such as perforation, occurred in response to UV treatment during the observation period. UV light was significantly more effective than visible light in preventing vasospasm (P <.001). CONCLUSION: These results suggest that endovascular UV irradiation after blood exposure has a prophylactic effect on vasospasm and suggest a dependence on irradiation wavelength and duration of irradiation.

Animals↗