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Biomedical subjects

N Tomura

Publications and source records attributed to N Tomura.

At least 19 recordsLinked to original sources
PubMed2006

Dural arteriovenous fistulas of the cavernous sinus with onset of intracerebral haemorrhage mimicking hypertensive putaminal hemorrhage.

We describe a patient with dural arteriovenous fistulas of the cavernous sinus (CS-dAVFs) who developed an intracerebral haemorrhage (ICH) mimicking hypertensive putaminal haemorrhage. Drainage into the superior ophthalmic vein (SOV) and inferior petrosal sinus (IPS) was not demonstrated on cerebral angiography, and only cortical venous reflux into the Sylvian vein was observed. In cases of venous drainage concentrated on the Sylvian vein, CS-dAVFs could indicate ICH with radiological appearance resembling putaminal haemorrhage.

Aged↗
PubMed2006

Postoperative three-dimensional CT angiography after cerebral aneurysm clipping with titanium clips: detection with single detector CT. Comparison with intra-arterial digital subtraction angiography.

AIM: To assess the significance of three-dimensional computed tomography angiography (3D-CTA) in detecting remnant necks after cerebral aneurysm clipping. MATERIALS AND METHODS: A total of 59 patients (77 aneurysms) underwent surgery using titanium clips. Two blinded observers independently evaluated the presence of neck remnants on shaded-surface display (SSD) imaging, volume rendered (VR) imaging, and intra-arterial digital subtraction angiography (IADSA). RESULTS: Mean sensitivity and specificity for detecting neck remnants were 50.0 and 74.2% for SSD imaging, 61.5 and 82.8% for VR imaging, and 92.3 and 92.2% for IADSA, respectively. Receiver operating characteristic (ROC) analysis revealed excellent diagnostic performance for IADSA [mean area under ROC curve (Az)=0.97], and good diagnostic performance for 3D-CTA (Az=0.70 and 0.76 for SSD and VR, respectively). Specificity of VR was better than that SSD (p=0.082), however, there was no significant difference between them. CONCLUSION: Use of 3D-CTA techniques can facilitate postoperative evaluation.

Adult↗
PubMed2006

Balloon occlusion test of the internal carotid artery: correlation with stump pressure and 99mTc-HMPAO SPECT.

PURPOSE: To evaluate the correlation of stump pressure during balloon occlusion test and relative cerebral blood flow (relative CBF) as measured by 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) after test occlusion. MATERIAL AND METHODS: Balloon occlusion test of the internal carotid artery (ICA) was performed in 25 patients. The count ratio of occluded hemisphere to non-occluded hemisphere was calculated on 99mTc-HMPAO SPECT. The ratio of mean stump pressure to mean arterial pressure during carotid occlusion during the balloon occlusion test was compared with the count ratio of 99mTc-HMPAO SPECT. RESULTS: Two patients failed to tolerate even brief carotid occlusion. The other 23 patients showed no ischemic deficit during occlusion of the ICA. In 13 of these 23 patients, the ratios of mean stump pressure to mean arterial pressure were more than 50%, and the count ratios on SPECT were more than 85%. In 10 of 23 patients, the ratios of mean stump pressure to mean arterial pressure were less than 50%, and the count ratios on SPECT were variable. CONCLUSION: Maintenance of a mean stump pressure of 50% or more of the mean systemic pressure during test occlusion indicates adequate cerebral blood flow during carotid occlusion.

Adult↗
PubMed2003

A primary retroperitoneal serous cystadenocarcinoma with clinically aggressive behavior.

CASE REPORT: We describe a 44-year-old woman with a primary retroperitoneal serous cystadenocarcinoma as the fourth report in the world literature. A contrast-enhanced computed tomographic scan of the abdomen demonstrated a mass with enhanced solid mural nodules and septa in the left retroperitoneum. Serum CA19-9 was elevated at 181 U/ml. The patient underwent a complete resection of the retroperitoneal tumor with a partial resection of the psoas major muscle and its fascia. Pathological examination showed a well-differentiated papillary serous cystadenocarcinoma of ovarian type and locoregional lymph node metastases. Seven months after surgery, the patient developed a pelvic recurrence, and underwent a total hysterectomy, a left salpingo-oophorectomy and a resection of the metastatic mesenteric mass. Two months after the second surgery, serum CA19-9 and CA125 increased to 1,114 U/ml and 218 U/ml, respectively. A solitary liver metastasis was confirmed on a computed tomographic scan. The patient is now being treated with weekly docetaxel and carboplatin. CONCLUSION: The present case illustrates the clinically aggressive nature of a primary retroperitoneal serous cystadenocarcinoma.

Adult↗
PubMed2001

Extradural neuromas at the petrous apex: report of two cases.

OBJECTIVE AND IMPORTANCE: Two rare cases of middle cranial fossa neuroma located in the epidural space at the petrous apex are reported. CLINICAL PRESENTATION: Two women, aged 58 and 49 years, were admitted to our hospital with diagnoses of cavernous sinus tumor. Analysis of preoperative computed tomography scans showed bone erosion of the petrous apex, and magnetic resonance imaging demonstrated the presence of an extradural mass located along the course of the petrous internal carotid artery in both patients. INTERVENTION: The tumor was completely removed in one patient and partially removed in the other by use of the epidural middle cranial fossa transpetrosal approach. In both patients, histological examination of tumor specimens revealed neuroma. CONCLUSION: Because surgical exploration revealed that these epidural tumors adhered tightly to the internal carotid artery, and because they had no relationship to the trigeminal nerve, facial nerve, or proximal greater superficial petrosal nerve, in our opinion, these tumors originated from the distal portion of the greater superficial petrosal nerve or the deep petrosal nerve. These neuromas were mainly found in a site under the cavernous sinus at the petrous apex, a location not previously reported.

Carotid Artery, Internal↗
PubMed2001

[A patient with Moyamoya-like vessels after radiation therapy for a tumor in the basal ganglia].

A patient with Moyamoya-like vessels after radiation therapy for treatment of a tumor in the basal ganglia is reported. He was diagnosed as Down syndrome at birth. He had a tumor in the left basal ganglionic region at 12 years of the age. The tumor increased in size at age 14. He underwent cerebral angiography, which did not show a stenosis nor occlusion of the internal carotid artery, anterior cerebral artery, nor the middle cerebral artery. He received radiation therapy with a total dose of 56 Gy. He presented a dressing apraxia at age 19. MRI showed cerebral infarction in the left temporo-occipital region. Right internal carotid angiography revealed a severe stenosis of the internal carotid artery and anterior cerebral artery as well as a severe stenosis of the middle cerebral artery on the right side. Moyamoya-like vessels were seen in the basal ganglionic region. Left internal carotid angiography also showed a stenosis of the internal carotid artery and anterior cerebral artery as well as a severe stenosis of the middle cerebral artery on the left side. Moyamoya-like vessels were seen in the basal ganglionic region. Leptomeningeal anastomose and transdural anastomose were bilaterally seen. These arterial occlusion and stenotic phenomenon corresponded to a previous radiation field. These Moyamoya-like vessels with arterial stenosis and occlusion were thought to be due to radiation-induced vasculopathy, because a previous cerebral angiography showed a normal caliber of cerebral arteries. This patient showed that patients with radiation therapy in their early childhood should be carefully observed considering the possibility of this phenomenon.

Adult↗
PubMed2000

High uptake of 123I-metaiodobenzylguanidine related to olfactory neuroblastoma revealed by single-photon emission CT.

We studied a case of olfactory neuroblastoma by noting 123I-metaiodobenzylguanidine (MIBG) uptake revealed by single-photon emission CT (SPECT). MR imaging revealed an enhancing tumor extending from the left nasal cavity to the bilateral anterior frontal cranial fossae. SPECT revealed high 123I-MIBG uptake in the enhancing tumor. SPECT-revealed 123I-MIBG uptake appears to be clinically useful for distinguishing olfactory neuroblastomas from other tumors, especially suprasellar meningiomas.

3-Iodobenzylguanidine↗
PubMed2000

[Imaging of tumors of the spine and spinal cord].

Imaging of the spine and spinal cord has traditionally been accomplished with plain radiography, myelography, and CT. Recently, MR imaging has become the technique of choice in the assessment of lesions of the spine and spinal cord. MR imaging provides accurate localization of intramedullary, intradural extramedullary, and extradural tumors. Ependymomas and low-grade astrocytomas are the most common intramedullary tumors. MR imaging findings are distinguishable by the delineation and size of the lesion, and the signal intensity on T2-weighted images. Other less common tumors include malignant astrocytomas, hemangioblastomas, and intramedullary metastasis. Numerous foci of high-velocity signal loss are seen in the hemangioblastomas. Metastasis, meningiomas, and schwannomas are the most common intradural extramedullary tumors. Meningiomas are characterized by dural enhancement on postcontrast T1-weighted images. Schwannomas and neurofibromas often erode bony structures and appear to be dumbbell-shaped. Epidural metastasis accounts for the majority of extradural tumors. Primary malignant extradural tumors include lymphomas, chordomas, and so on. The most common primary benign extradural tumor is hemangioma, which often appears to be hyperintense on both T1-weighted and T2-weighted images. Intramedullary non-neoplastic lesions include demyelinating, vascular, and infectious diseases. Diffuse, peripheral, or speckled contrast enhancement, and lack of contrast enhancement may suggest non-neoplastic lesions.

Astrocytoma↗
PubMed1999

Comparison of MR imaging with CT in depiction of tumour extension into the pterygopalatine fossa.

The computed tomography (CT) and magnetic resonance imaging (MRI) results of 30 consecutive patients with tumours in the skull base, and who had abnormalities of the pterygopalatine fossa (PPF) on CT or MRI, were retrospectively compared with respect to visualization of tumour infiltration into the PPF. CT did not depict the abnormalities in the PPF in five patients (17%), while unenhanced T1-weighted MR images depicted tumour infiltration in all patients. Obliteration of PPF fat was better visualized on CT than T2-weighted and proton density weighted MR images, as were bony abnormalities. On MRI, intracranial extension was seen in eight of 25 patients with extracranial tumour. MRI is a sensitive method of demonstrating both tumour infiltration of the PPF and perineural tumour spread.

Adolescent↗
PubMed1998

Development of a huge varix following endovascular embolization for cerebellar arteriovenous malformation. A case report.

We report on the case of a huge varix that developed after the endovascular embolization of a cerebellar arteriovenous malformation (AVM) with a single drainer. A 21-year-old male presented with trigeminal neuralgia which was caused by the dilated drainer of the AVM. A varix was found at the basal vein of Rosenthal 2 months after an initial stage of embolization with polyvinyl alcohol particles; it diminished after the surgical extirpation of the AVM. The varix formation might have been facilitated by the stenosis in the vein of Galen and by the dynamic changes that followed the embolization. This rare complication should be kept in mind when embolization is performed for AVMs with impaired venous outlets.

Adult↗
PubMed1998

Therapeutic results of intra-arterial chemotherapy in patients with malignant glioma.

Thirty-three adult patients with anaplastic astrocytoma or glioblastoma multiforme, verified between 1990 and 1997, received postoperative intra-arterial ACNU chemotherapy and irradiation. Since our previous strategies to malignant gliomas had included intra-venous ACNU, the purpose of the present study is to evaluate the advantage of intra-arterial ACNU over its intra-venous counterpart as the historical control (37 patients). The median survival was 74.7 weeks for the former and 81.7 weeks for the latter. Although both groups were equivalent in survival, toxicity was less frequent in the intra-arterial group. Histopathological diagnosis, patient age and the Karnofsky's performance status related well with the survival.

Adult↗
PubMed1998

[Brain magnetic resonance imaging findings in two cases of Hunter's syndrome].

Magnetic resonance (MR) imaging findings in two cases of Hunter's syndrome [mucopolysaccharidosis (MPS) type II A] are reported. The first case is a 15-year-old boy in whom the diagnosis of Hunter's syndrome was made at 2 years of age on the basis of increased glycosaminoglycans in the urine, developmental delay, characteristic faces, joint contraction, family histories, and radiological characteristics including oar-like deformed ribs and dysplasia of lumbar vertebrae. MR images showed marked enlargement of the lateral ventricles and third ventricle. The cerebral cortical sulci were diffusely dilated. Abnormal intensity lesions in the lateral part of the lentiform nucleus, the subcortex of the insula, the pons, and the right thalamus were seen. Diffuse hyperintensity throughout the periventricular white matter is also seen on T2-weighted images. The second case is a 3-year-old boy, born at immature delivery. At 2 months of age, he was admitted to a pediatric department because of liver dysfunction, inguinal hernias and umbilical hernia. The diagnosis of Hunter's syndrome was made by developmental delay, gargoylism, joint contraction, kyphosis, and biochemical investigation of urine. Urinary glycosaminoglycans significantly increased. Skeletal radiography showed dysplasia of the lumbar vertebrae and acetabulum. T1-weighted MR images demonstrated numerous hypointense spots in the corpus callosum and the cerebral white matter, presumably suggesting large perivascular spaces. Multiple cystic changes appeared to be hyperintense on T2-weighted images. Numerous linear hyperintense lesions were visible in the corona radiata. Patchy areas of hyperintense areas were seen, more prominent in the parietal lobes. Neuropathological examinations in cases of Hunter's syndrome have previously shown marked dilatation of ventricular system, large perivascular spaces secondary to mucopolysaccharide storage, demyelination and gliosis in the white matter and so forth. MR findings correlated well with previously reported neuropathological findings. MR study is not only useful for diagnosing Hunter's syndrome but also helpful to follow the pathological status.

Adolescent↗
PubMed1998

[Superficial siderosis appeared in a case of suprasellar embryonal carcinoma].

A case of superficial siderosis that appeared in a case of suprasellar embryonal carcinoma is reported. A 24-year-old man presented polydipsia and vertigo. MRI revealed a suprasellar tumor. The tumor contained high intense spots on T1-weighted images, suggesting intratumoral hemorrhage. He underwent a surgery, which proved it as embryonal carcinoma pathologically. Cerebrospinal fluid was xanthochromic at surgery, suggesting terminal hemorrhage. After surgery, he received a total dose of 56 Gy of irradiation. Tumor decreased in size and symptoms improved. However, he presented occipital headache 7 months after surgery. MRI showed disseminated tumors in the subarachnoid spaces. He received irradiation for the whole spine and adjuvant chemotherapy. During treatment, MRI demonstrated low signals on the surface of the brain stem, suggesting the superficial siderosis. The lesions spread to the surface of the cerebellum and tentorium cerebelli. Superficial siderosis is characterized by the deposition of hemosiderin in the leptomeninges, cranial nerves and spinal cord. The etiology of the hemosiderin deposition is thought to be chronic or recurrent bleeding into subarachnoid space. Experimentally, similar lesions have been produced in the animals following intrathecal injection of blood or hemolysed red cells. In the literature, MRI demonstrated a rim of marked hypo-intensity on T2-weighted images, consistent with hemosiderin deposits, on the surface of cerebellum and brain stem. Gradient-echo sequences have been more sensitive than T2-weighted images of spin echo sequences. In the present case, the superficial siderosis seems to be due to chronic tumoral hemorrhage. This phenomenon could be related to chemotherapy using CDDP and etoposide.

Adult↗
PubMed1997

[Evaluation of single photon emission computed tomography of tumors in the head and neck with technetium-99m MIBI].

SPECT using 99mTc-MIBI was performed in patients with tumors in the head and neck in order to determine 99mTc-MIBI uptake in tumors and to evaluate the efficacy of 99mTc-MIBI imaging in the assessment of treatment response. A MIBI uptake index was calculated as the ratio of average counts/pixel in the tumor to average counts/pixel in the homologous contralateral side. Eighteen of 19 (95%) of the cases had increased MIBI uptake in the tumor on early images, and 8 of 14 (57%) of the cases had increased uptake of the tumor on delayed images. MIBI uptake was related to the size of the tumor. Only 6 of 25 of cervical lymph node metastases were detected by 99mTc-MIBI SPECT. In the tumors evaluated before and after radiotherapy, the superiority of 99mTc-MIBI SPECT over MRI was not obtained, but there was a tendency for MIBI-index to decrease after radiotherapy.

Adult↗
PubMed1997

[Central nervous system involvement of leukemia and systemic lymphoma in children: CT and MR findings].

The purpose of this paper is to retrospectively evaluate CT and MR findings of central nervous system (CNS) involvement of leukemia and systemic lymphoma in children. Over a 12-year period, sixty-five patients with leukemia and fifteen patients with systemic lymphoma underwent cerebral CT and/or MR imaging. Nine patients (11.3%) were diagnosed as CNS involvement of leukemia and lymphoma. The diagnostic criteria of CNS involvement were as follows; 1) Histological proof was confirmed by surgery, 2) Tumor cells were found in the cerebrospinal fluid examinations, 3) Increase in size of the lesion during observation without specific treatment, and 4) Response to the treatment for leukemia or lymphoma. All of nine patients fulfilled more than two criteria of 1)-4). The CT and MR abnormalities in these patients were correlated with the findings of histology, cerebrospinal fluid cytology, and/or treatment. The age of the patients ranged from 0 to 15 years old. They consisted of 6 boys and 3 girls. The CT examinations were performed before and after contrast administration. MR examinations were performed on a 1.5-T unit, and T1-weighted, T2-weighted, and proton density-weighted images were obtained using spin-echo or fast spin-echo sequences. Tumor masses were present in seven with leukemia (acute lymphoblastic leukemia 4; acute myeloblastic leukemia 1; acute promyelocytic leukemia 1; acute monocytic leukemia 1), and in two with malignant lymphoma. On the CT scan, tumor masses were hyperdense with contrast enhancement. On the MR images, their signals were variable. In all of nine patients, tumor masses were contiguous with a meningeal surface. Postcontrast T1 weighted images were valuable in demonstrating meningeal infiltration. Tumoral hemorrhage was found in two patients. In a patient with tumor at the superior sagittal sinus, venous infarct was observed. CNS leukemic and lymphomatous masses are almost hyperdense on the CT and they are characteristically contiguous with a meningeal surface. MR imaging was valuable in demonstrating meningeal infiltration. Findings of CT and MR imaging, cerebrospinal fluid examinations, and response to the treatment are useful in the differentiation of CNS involvement of leukemia and lymphoma from other lesions such as infectious diseases and leukoencephalopathy.

Adolescent↗
PubMed1996

Cerebral oxygen and glucose metabolism and blood flow in mitochondrial encephalomyopathy: a PET study.

Cerebral blood flow (CBF), oxygen metabolism (CMRO2), and glucose metabolism (CMRGlc) were measured using positron emission tomography in five patients diagnosed as having mitochondrial encephalomyopathy. The molar ratio between the oxygen and glucose consumptions was reduced diffusely, as CMRO2 was markedly decreased and CMRGlc was slightly reduced. The CBF showed less changes. The CBF increase on hypercapnia was smaller than normal, though this was not significant. CBF with hypocapnia demonstrated a significant reduction compared with the normal. These results suggest that oxidative metabolism is impaired and anaerobic glycolysis relatively stimulated, due to a primary defect of mitochondrial function, and that mild lactic acidosis occurs in brain tissue because of impaired utilisation of pyruvate in the TCA cycle. As these findings appear to indicate directly a characteristic of this disease, such measurements may be a useful tool for assessment of the pathophysiology and for diagnosis of mitochondrial encephalomyopathy.

Acidosis, Lactic↗