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Biomedical subjects

J Watarai

Publications and source records attributed to J Watarai.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Three-dimensional computed tomography in the head and neck diseases with bony abnormalities.

The purpose of this study was to define the role of three-dimensional (3D) computed tomography (CT) in the head and neck diseases with bony abnormalities. Thirty-two patients were examined with a low dose radiation technique. Three-dimensional CT clearly delineated bony lesions in 27 of 32 patients. Three-dimensional CT could not demonstrate subtle bony erosions infiltrated by tumor, a temporal bone fracture, and a blow-out fracture, although two-dimensional (2D) images obtained before the 3D reconstructions clearly depicted those lesions. These two kinds of CT technique were thought to be complimentary.

Bone Diseases↗
PubMedDate not supplied

Germ cell tumors of the central nervous system originating from non-pineal regions: CT and MR features.

CT and MR findings were retrospectively reviewed in 12 patients with germ cell tumors originating from the non-pineal regions. Cystic or necrotic components were seen in 6 patients. Of 4 germinomas, 2 showed mixed density on the CT. The MR signal intensity of the tumor was non-specific. Of 8 germinomas, 4 were inhomogeneously enhanced on postcontrast CT and T1-weighted MR images. CT and MR features of germinomas originating from non-pineal regions frequently differ from those of germinomas originating from the pineal region. The mass of the tumor often appeared cystic and inhomogeneously enhanced following contrast infusion.

Adolescent↗
PubMedDate not supplied

Preliminary results with technetium-99m MIBI SPECT imaging in patients with brain tumors: correlation with histological and neuroradiological diagnoses and therapeutic response.

SPECT using Tc-99m MIBI was performed in patients with brain tumors in order to determine Tc-99m MIBI uptake in brain tumors and to evaluate the efficacy of MIBI imaging in the assessment of treatment response. A MIBI uptake index was calculated on SPECT imaging. All tumors with a MIBI-index higher than 7.5 were malignant. In the tumors evaluated before and after radiochemotherapy, the MIBI-index immediately following therapy correlated with treatment response 2 months after therapy. Thus, semiquantitative assessment using Tc-99m MIBI SPECT imaging may be useful in the evaluation of treatment response.

Adolescent↗
PubMedDate not supplied

Caudal regression syndrome: MR appearance.

This article reports a case of caudal regression syndrome with hypoplasia of the sacrum, accompanied by an imperforate anus with ano-vestibular fistula. Magnetic resonance images showed a characteristic wedge-shaped cord terminus and the separation of anterior and posterior spinal roots at the level of the cauda equina.

Anus, Imperforate↗
PubMedDate not supplied

Comparison of MR imaging and CT in discriminating tumor infiltration of bone and bone marrow in the skull base.

We compared MR imaging with CT in revealing tumor infiltration of bone and bone marrow in the skull base of 54 patients. MR imaging had no advantages over when tumor involved the anterior compartment. However, precontrast T1-weighted MR images were more efficient than CT in 37.5% of tumors involving the middle compartment and in 54.5% of tumors involving the posterior compartment, respectively. Precontrast T1-weighted images were more accurate than other pulse sequences in revealing bone and bone marrow that were replaced by tumors.

Adenoma↗
PubMedDate not supplied

Unexpected accumulation of thallium-201 in cerebral infarction.

Three cases of cerebral infarct that unexpectedly showed accumulation of thallium-201 on single photon emission CT are presented here. In the first case, infarction developed following removal of an intracerebral hematoma. In the second case, infarction developed due to deep venous thrombosis as demonstrated by angiography. In the third case, hemorrhagic infarction was diagnosed by the follow-up CT. The findings in these cases demonstrate that thallium-201 accumulation may occur in the liquefaction stage of cerebral infarction.

Aged↗
PubMedDate not supplied

Transient neurotoxicity associated with FK506: MR findings.

We report a patient presenting with transient neurotoxicity who developed edema in the cerebral and cerebellar cortex following bone marrow transplant and administration of FK506, a widely used immunosuppresive agent.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Changes in cerebral blood flow in bulimia nervosa.

Bulimia nervosa is an eating disorder of which characterized psychopathological symptoms are a recurrent episode of binge eating. The changes in cerebral blood flow (CBF) in a patient with bulimia nervosa between his or her different eating phases are presented. CBF was measured quantitatively by means of single photon emission computed tomography using I-123 N-isopropyl-p-iodoamphetamine. CBF of the global brain during a binge-eating phase was higher than that during an anorexic state phase. In the anorexic state, the CBF in the temporal, parietal, and occipital lobes on the right side was lower than that on the left side. In the binge-eating state, a lack of laterality between the right and left cerebral hemispheres was found. This finding suggests that cerebral activity differs between the two phases, and that asymmetry is dependent of the eating state.

Adult↗
PubMedDate not supplied

Comparison of thallium-201 and gallium-67 imaging in evaluation of head and neck tumors.

PURPOSE: 201Tl imaging was compared with 67Ga imaging in the detection of malignant head and neck tumors. METHOD: Eighteen patients with tumors in the head and neck region underwent both planar and SPECT imaging using 201Tl-chloride and 67Ga-citrate. The detection of primary tumors and lymph node (LN) metastases by visual evaluation was compared between 201Tl and 67Ga imaging. Additionally, quantitative analysis of the SPECT images was performed in eight patients. RESULTS: On visual evaluation, primary tumor uptake was detectable in 100% on the 201Tl SPECT images compared with 44% on the 67Ga SPECT images. The sensitivity, specificity, and accuracy of 201Tl in detecting LN metastases were higher than those of 67Ga SPECT; however, there was no statistical difference between 201Tl and 67Ga. The tumor-to-background ratio was significantly higher on 201Tl SPECT than on 67Ga SPECT. CONCLUSION: This study suggested that 201Tl could be useful in the evaluation of malignant tumors in the head and neck region.

Aged↗
PubMedDate not supplied

A case of moyamoya-like vessels combined with brain anomaly.

We report here a rare case of moyamoya-like vessels combined with brain anomaly. MR imaging revealed a small corpus callosum and stenosis of the internal carotid arteries. T2-weighted images revealed multiple hyperintense lesions in the cerebral deep white matter, suggesting ischemic or abnormal myelinated tissues. Cerebral angiography showed aplastic carotid siphons and anomalous aneurysmal dilatation of the petrous portion of the internal carotid arteries. The terminal portion of the internal carotid arteries and horizontal portion of the middle cerebral artery were stenotic with moyamoya-like vessels.

Brain↗
PubMedDate not supplied

Small cell carcinoma of the lung: CT findings of parenchymal lesions.

PURPOSE: The purpose of this study was to describe the CT findings of small cell carcinoma of the lung. MATERIALS AND METHODS: CT findings were retrospectively reviewed in 38 patients (34 men, 4 women; aged 46-73 years) with pathologically proven small cell carcinoma. RESULTS: Tumors were located centrally in 23 cases (61%) and peripherally in 15 cases (39%). Twenty-seven patients had a bulky central mass with encasement of the great vessels or extrinsic compression of the airway (22 central tumors, 5 peripheral tumors). Six patients had peripheral lesions without adenopathy. Five peripheral small cell carcinomas demonstrated peribronchial thickening adjacent to the primary tumor. CONCLUSION: The first sign of small cell carcinoma most typically is a bulky central mass that represents metastasis to the hilar and/or mediastinal lymph nodes. Although no findings specific to peripheral small cell carcinoma are available, small cell carcinoma originating from the peripheral lung parenchyma should be included in the differential diagnosis when peribronchial thickening is associated with the tumor.

Aged↗
PubMedDate not supplied

Fundamental dose distribution for interstitial irradiation with Au grains.

A principle of radiation therapy is to determine a proper dose distribution for tumor localization. In this paper we present several models of arranging Au grains for interstitial irradiation and discuss characteristics of their dose distributions. Au grains were arranged in a lattice of three by three for evaluation of isodose curves on a source plane and several planes parallel to it. Intersource distances were varied to determine adequate distances for ideal dose distributions for tumor control. Through this study, we concluded that the most favorable intersource distance for effective dose distribution was 1.0-1.25 cm. We also found that interstitial irradiation with Au grains was hard to apply to deeply spreading tumors.

Brachytherapy↗
PubMedDate not supplied

Oropharyngeal cancer: clinical efficacy of ultrasound.

Nine patients with carcinoma of the oropharynx were evaluated for classification of the primary tumor by ultrasonography (US). US accurately defined tumor size. In cancers of the tonsils, spread toward the tongue was correctly assessed by US. Tumor classification of T1 to T4 was possible in all patients. Small oropharyngeal cancers showed a homogeneous hypoechoic pattern. As the tumor enlarged, internal echoes became heterogeneous. US was also useful in evaluating the response to radiation by monitoring the tumor size. Our results showed that US was a valuable adjunct to current techniques for imaging oropharyngeal tumor.

Adult↗
PubMedDate not supplied

Preliminary study of uneven fractionation radiotherapy combined with chemotherapy for esophageal cancer.

Between March 1992 and September 1993, nine patients were treated with combined-modality therapy of uneven fractionation radiotherapy and chemotherapy (CDDP+ 5-FU) before esophagectomy. All patients had a T4 tumor that was evident on the chest CT scan, MRI, or bronchofiberscopy. In the uneven fractionation radiotherapy, patients received 5 Gy on Fridays and daily doses of 1.2 Gy the following Monday through Thursday for 22 days, to yield a total dose of 34.4 Gy. CDDP (40 mg/body) was administered intravenously as a slow infusion just before each 5 Gy treatment for a total of five doses. 5-FU (300 mg/m2/day) was also administered intravenously as a slow infusion for each of the 22 treatment days. As restaging failed to document a significant response (improvement to T3 or better), a further dose of irradiation was given in two patients (22%). Five patients (56%) had a partial response. The tumors in eight patients (89%) could be resected after this combined modality treatment. Histological assessment of the resected specimens indicated grade 3 in two patients and grade 2 in six patients. At a median follow-up of 14 months, seven patients are alive and four patients are clinically disease free. Uneven fractionation radiotherapy combined with chemotherapy improved local control and the resectable rate in these patients.

Adult↗
PubMedDate not supplied

Retrobulbar orbital metastasis mimicking meningioma.

A 45-year-old woman was found to have an intraorbital mass on CT. CT images showed a markedly enhanced retrobulbar mass with optic nerve lucency, producing a characteristic "tram-track" sign. Signal intensity patterns on spin-echo MRI seemed to indicate meningioma. The pathological diagnosis was scirrhous carcinoma of the breast. This case was not distinguishable from meningioma on CT or MRI.

Adenocarcinoma, Scirrhous↗
PubMedDate not supplied

Local control of prostate cancer with transurethral intracavitary radiation therapy.

As of January 1986, 13 patients with adenocarcinoma of the prostate had been treated in our clinic by remote after-loading transurethral high dose rate radiotherapy using a 60Co source. Of these patients, four were at stage B2, three at stage C, three at stage D1, and three at stage D2. The mean total dose of transurethral radiotherapy was 35.2 Gy to the most distant prostatic capsule from the source. Three patients with stage D1 disease and one patient with stage C disease received additional external radiation with a total dose of 20 Gy to the prostate and 40 Gy to the pelvis. Local tumor response proved rapid and satisfactory as verified by rectal examination, ultrasonography, and needle biopsy. Serious complications such as proctitis, cystitis, incontinence, and urethral stricture were not evident during the average follow-up term of 34.9 months.

Adenocarcinoma↗
PubMedDate not supplied

A needle maintenance device for interstitial irradiation of oral floor carcinoma.

It is difficult to precisely position the needles for interstitial irradiation during implantation. We created a needle maintenance implant device to fix the needles in the correct positions. The device is composed of a thin-walled teeth cap made from cellulose acetobutylate, a polymer resin plate, and a lid made from resin. Implant needles are inserted through holes in the device and stability is maintained during the entire procedure.

Brachytherapy↗