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Biomedical subjects

Y Numaguchi

Publications and source records attributed to Y Numaguchi.

176 records · Page 10Linked to original sources

Posttraumatic cerebral infarction diagnosed by CT: prevalence, origin, and outcome.

Posttraumatic cerebral infarction is a recognized complication of craniocerebral trauma, but its frequency, cause, and influence on mortality are not well defined. To ascertain this information, all cranial CT studies demonstrating posttraumatic cerebral infarction and performed during a 40-month period at our trauma center were reviewed. Posttraumatic cerebral infarction was diagnosed by CT within 24 hr of admission (10 patients) and up to 14 days after admission (mean, 3 days) in 25 (1.9%) of 1332 patients who required cranial CT for trauma during the period. Infarcts, in well-defined arterial distributions, were diagnosed either uni- or bilaterally in the posterior cerebral (17), proximal and/or distal anterior cerebral (11), middle cerebral (11), lenticulostriate/thalamoperforating (nine), anterior choroidal (three), and/or vertebrobasilar (two) territories in 23 patients. Two other patients displayed atypical infarction patterns with sharply marginated cortical and subcortical low densities crossing typical vascular territories. CT findings suggested direct vascular compression due to mass effects from edema, contusion, and intra- or extraaxial hematoma as the cause of infarction in 24 patients; there was postmortem verification in five. In one patient, a skull-base fracture crossing the precavernous carotid canal led to occlusion of the internal carotid artery and ipsilateral cerebral infarction. Mortality in craniocerebral trauma with complicating posttraumatic cerebral infarction, 68% in this series, did not differ significantly from that in craniocerebral trauma patients without posttraumatic cerebral infarction when matched for admission Glasgow Coma Score results. Thus, aggressive management should be considered even in the presence of posttraumatic cerebral infarction.

Adult↗

Myelography with metrizamide: effect of contrast removal on side effects.

Moderately severe side effects, such as prolonged headache, nausea, vomiting, or psychoneurologic symptoms, were noted in 27 (32%) of 84 patients in whom the contrast medium was not removed. Conversely, among 73 patients from whom 20-25 ml of cerebrospinal fluid with the contrast medium was removed, only 10 (14%) experienced adverse effects, a statistically significant reduction. Although new contrast agents, such as iohexol and iopamidol, are reportedly less toxic than metrizamide, the contrast-removal technique described here may be indicated when large amounts of any contrast medium are used.

Contrast Media↗

Non-enhancing supratentorial malignant astrocytomas: MR features and possible mechanisms.

To clarify the MR features of supratentorial malignant astrocytic gliomas that did not exhibit contrast enhancement of MR imaging, six MR parameters were evaluated in two glioblastomas and six anaplastic astrocytomas. Moderate to marked edema, mass effect, and moderate tumor heterogeneity were noted in all cases. Hemorrhage was absent in all cases. Border definition and cyst formation or necrosis were not consistent among the tumors. Histological examination demonstrated significant vascular proliferation in two cases, and mild to moderate proliferation in six. Non-enhancing malignant astrocytic gliomas are a diagnostic challenge. Analyzing perifocal edema and heterogeneity of each mass probably provides clues for a proper diagnosis.

Adolescent↗

MR imaging of adult supratentorial astrocytomas: an attempt of semi-automatic grading.

Using multiple regression analysis, six MR parameters were correlated with three histological grades among 43 proven adult supratentorial astrocytic gliomas to ascertain important MR parameters and their optimal contributions. Analysis revealed that two parameters, border definition and tumor hemorrhage, were unreliable. Using the remaining four parameters an equation was derived: Tumor grade = 0.32 (ring enhancement) +0.29 (degree of contrast enhancement) +0.13 (heterogeneity) +0.12 (edema) +0.41. Ring enhancement was the most reliable predictor of tumor grade, followed by degree of contrast enhancement. The maximum accuracies of the "semi-automatic" approach using this equation for predicting low-grade astrocytomas, anaplastic astrocytomas, and glioblastoma multiforme were 91%, 83%, and 88%, respectively. Although "semi-automatic" grading provided relatively high accuracy, possible sampling errors and some atypical cases reduced such accuracy.

Adult↗

Scalloping deformity of the corpus callosum following ventricular shunting.

PURPOSE: To describe six patients who underwent ventriculoperitoneal (V-P) shunting for hydrocephalus and developed scalloping deformity of the dorsal surface of the corpus callosum, and to evaluate the cause and frequency of this phenomenon. MATERIALS AND METHODS: MR images of 35 patients whose hydrocephalus was successfully corrected by V-P shunting were studied. To elucidate the possible anatomic basis for the scalloping deformity, gross examination of the corpus callosum relative to the adjacent anatomical structures was performed using autopsy specimens. RESULTS: Of the 35 patients who underwent successful V-P shunting, six (17%) developed a scalloping deformity of the corpus callosum. The deformity was noted exclusively in the body of the corpus callosum. This phenomenon was observed in both obstructive and communicating hydrocephalus regardless of the patient's age, but was particularly noted in patients with tectal tumors. CONCLUSION: The cause of this phenomenon may be a combination of long-standing hydrocephalus and normal pericallosal artery anatomy. Prolonged hydrocephalus softens the corpus callosum and the branches of the pericallosal arteries tether the corpus callosum to the overlying cingulate cortex at periodic intervals.

Adolescent↗

Spinal epidural venous plexus: its MR enhancement patterns and their clinical significance.

OBJECTIVE: Evaluation of the clinical utility of enhancement of the spinal epidural venous plexus (SEVP) on postcontrast MR imaging. MATERIALS AND METHODS: The SEVP on pre- and postcontrast T1-weighted sagittal and axial MR images were evaluated in 188 patients whose MR findings were abnormal (positive group), in 223 patients with normal MR (negative group), and in 35 volunteers. The enhancement patterns of the SEVP were graded 1 to 4 according to their degree of dilation. These three groups were compared and analyzed. RESULTS: Epidural and intradural lesions in the positive group showed higher grades of epidural vein enhancement compared with the negative group (p = 0.01). Epidural abscesses and epidural metastases frequently showed moderate to marked dilatation of the SEVP. Degenerative disk disease with stenosis of the spinal canal exhibited more localized patterns of dilation. Most intradural lesions with cord swelling demonstrated dilation of the SEVP. Visualization of the SEVP did not differ statistically between bone and soft tissue lesions in the positive group and the negative group (p = 0.13). Evaluation of follow-up examinations showed that changes in SEVP grades were indicative of changes in disease. CONCLUSION: SEVP enhancement patterns assist in the evaluation of disease in the spinal canal and will help to differentiate normal from pathological conditions.

Abscess↗

CT angiography in the evaluation of acute stroke.

PURPOSE: To determine the worth of CT angiography of the circle of Willis as a supplement to routine CT in the examination of patients with symptoms of acute stroke in terms of its depiction of the number and distribution of arterial stenoses or occlusions. We also sought to compare the accuracy of CT angiography with MR angiography and/or digital subtraction angiography (DSA). METHODS: One hundred forty-five patients with symptoms of acute stroke were examined with routine head CT and CT angiography of the circle of Willis. MR angiography was also performed in 27 patients and DSA in 28 patients. CT and MR angiograms and DSAs were reviewed for stenoses or occlusions involving the vessels about the circle of Willis. MR and CT angiograms were also evaluated for image quality, and the corresponding routine CT and MR studies were evaluated for the presence of arterial infarction. RESULTS: CT angiograms were rated good or excellent in 89% of cases whereas MR angiograms were rated good or excellent in 92% of cases. Arterial stenoses or occlusions were present on 43% of CT angiograms, 48% of MR angiograms, and 21% of DSAs. Findings were in agreement in 98% of the vessels analyzed by CT angiography and MR angiography. Similarly, there was overall agreement of findings in 99% of vessels analyzed by CT angiography and DSA. None of the patients had any immediate adverse reactions after administration of intravenous nonionic iodinated contrast material. CONCLUSION: CT angiography is an accurate and safe method for evaluating arterial stenoses or occlusions in the vessels about the circle of Willis. CT angiography should be used in patients with symptoms of acute stroke for whom evaluation of the intracranial vasculature is desirable.

Adult↗

Symptomatic vertebral hemangioma: atypical spoke-wheel trabeculation pattern.

We present a case of symptomatic vertebral hemangioma in a 49-year-old woman who presented with abrupt onset of left lower extremity symptoms. MR images showed an unusual spoke wheel trabeculation pattern on the axial CT and MR images. Because the entire vertebral body was involved, exclusion of malignant tumor was necessary.

Female↗

Reversible symptomatic venous congestion after treatment of dural arteriovenous fistula using NBCA.

We treated a 73-year-old man with a dural arteriovenous fistula (AVF) with cortical venous drainage of the left mastoid region using transarterial embolization of the middle meningeal and occipital arteries with n-butyl 2-cyanoacrylate (NBCA). The patient's clinical symptoms improved dramatically. Three months after the procedure, follow-up CT showed resolution of white matter edema and follow-up angiograms showed no evidence of a recurrent AVF. This report indicates that dural AVFs without sinus drainage can be cured solely with transarterial NBCA embolization.

Aged↗