Biomedical subjects

J Watarai

Publications and source records attributed to J Watarai.

99 records · Page 6Linked to original sources

PubMedDate not supplied

New modality of radiation therapy under increased tumor oxygen tension with angiotensin II: a pilot study.

Elevation of the mean arterial blood pressure to approximately 150 mmHg by infusion of angiotensin II (AT II) resulted in a selective increase of blood flow in tumor tissue. A concomitant increase in tumor oxygen tension was also observed, suggesting the possibility of hyperbaric oxygenation radiation therapy. By controlling the infusion rate of AT II, mean blood pressure was increased up to 1.5-fold of normotension, and radiation was given (AT II-RT). Forty-one patients with recurrent tumors after intensive radiation therapy or with locally far advanced tumors were treated. Using an uneven dose fractionation scheme, total dose ranged from 5,100 to 7,800 cGy. The radiation response to the tumor was quite good. Including three complete responders, more than 50% tumor regression was obtained in 24 patients (58.5%), less than 50% in 13 (31.7%) and no effect in four (9.7%). On the other hand, damage to normal tissue was minimal, and no serious morbidity was experienced. For example, comparing the results in the two groups of lung cancer patients treated with or without AT II, superiority of AT II-RT was indicated. The curative ability of AT II-RT will be investigated further.

Angiotensin II↗

PubMedDate not supplied

Superselective angio-CT of brain tumors.

PURPOSE: To determine the efficacy of superselective angio-CT in the diagnosis of astrocytoma. METHODS: Nineteen patients with astrocytoma had superselective angio-CT before chemotherapeutic agents were administered via superselective intraarterial infusion. CT was performed after contrast material was delivered through a microcatheter, which had been advanced into the feeding arteries of the tumor. Superselective angio-CT scans were compared with digital subtraction angiograms, conventional contrast-enhanced CT scans, and contrast-enhanced T1-weighted MR images. RESULTS: Superselective angio-CT scans depicted contrast enhancement of the tumor in all of the patients and the medullary veins of the tumors in 32% of the patients. Digital subtraction angiograms showed tumor stains in 68% of the patients and the medullary veins in only 5%. Conventional CT scans and MR images showed contrast enhancement of the tumor in 89% of the patients. Superselective angio-CT scans confirmed the proper position of the catheter tip for the infusion of a chemotherapeutic agent. CONCLUSIONS: Superselective angio-CT can be used to depict contrast enhancement of tumors and the vascular structures that are characteristic of astrocytomas.

Adult↗

PubMedDate not supplied

Angiographic anatomy of the first and second segments of the maxillary artery.

The increasing use of interventional angiography makes it important to know the anatomy of the maxillary artery. The course and ramification pattern of the first and second segments of this artery were studied angiographically in 100 cases. The branches of the maxillary artery were identified on lateral stereoscopic images. The maxillary artery has three segments divided by the external pterygoid muscle, and the second of these segments divides into superficial and deep types. Of the 100 Japanese angiograms, 93% were of the superficial type and 7% of the deep type. The 93% was a much higher incidence than in Western populations. In the superficial types, the middle deep temporal artery and inferior alveolar artery arose separately from the maxillary artery, while in the deep types, they had a common trunk. This made it easy to differentiate the two types. The maxillary artery was classified into four subgroups (Ia, Ib, IIa and IIb) by the ramification patterns of the middle meningeal and accessory meningeal arteries from the first segment.

Angiography, Digital Subtraction↗

PubMedDate not supplied

Computed tomographic appearance of closed-loop obstruction.

The obstruction of a bowel segment at two points results in closed-loop obstruction, and is apt to cause strangulation. Thus, the early recognition of closed-loop small bowel obstruction might reduce the mortality rate. However, plain films are limited in their ability to diagnose it. Using previously described criteria, we retrospectively reviewed the CT images of six surgically confirmed cases of closed loop obstruction. In all patients, CT showed the characteristic configuration of closed loops, specific findings detected at the site of obstruction, or both. On the basis of our experience, CT is a useful, non invasive method for the investigation of patients with suspected closed-loop obstruction.

Adult↗

PubMedDate not supplied

Growth patterns of benign and malignant thyroid tumors estimated by CT.

Thyroid tumors affect adjacent structures and reveal their nature as they grow. Differences in benign and malignant tumor growth patterns were studied by CT. Twenty-nine benign (follicular adenoma) and 29 malignant (papillary carcinoma) tumors with their findings were arranged according to size to speculate on how they grew. Benign tumors grew expansively and made a beak-like appearance in the marginal thyroid tissue (beak sign). They displaced vessels but kept a fat plane or deep sulcus between them (sulcus sign). Malignant tumors, on the other hand, grew invasively and reached the trachea rapidly without the beak sign. They destroyed the fat plane and contacted the vessels without the sulcus sign. Expansive and invasive growth forms of benign and malignant thyroid tumors could be represented schematically.

Adenoma↗

PubMedDate not supplied

Dual phased array coils for high-resolution MRI of the shoulder.

We connected two 3-inch coils to a dual phased array receiver system and sandwiched the shoulder between the two coils. To obtain a quantitative assessment of the improved SNR, we imaged a phantom with both the dual phased array coils and the standard shoulder coil. SNR as a function of distance from the coils was computed by the National Electrical Manufacturers Association (NEMA) standard. At the expected depth of the humeral head, the SNR of the phased array coils on single excitation was 1.42 times that of the standard shoulder coil on two excitations. The higher quality of the images on single excitation shortened the imaging procedure. The dual phased array coils realized the minimum FOV: 8 cm with a pixel of 0.31 x 0.41 mm. The dual phased array coils achieved high spatial resolution images of the shoulder with significantly shorter imaging times.

Adult↗

PubMedDate not supplied

Comparison of fast spin-echo and conventional spin-echo sequences in the MR diagnosis of rotator cuff tears.

The fast spin-echo (FSE) technique has been a successful alternative to conventional spin-echo (CSE) imaging in the brain, spine, and pelvis, but not in the knee. This study evaluated the performance of the FSE technique in comparison with the established CSE technique as a reference standard. Oblique coronal images of 30 shoulders were obtained by both FSE and CSE techniques. The FSE images were compared with CSE images in terms of blurring and motion artifact, fat signal intensity, structural conspicuity, and visualization of joint effusion and rotator cuff tears. We imaged 30 consecutive patients with suspected rotator cuff tears who were referred for MR examination. FSE images often were worse in blurring and motion artifact than CSE images. FSE images showed higher fat signal intensity, but visualized structural conspicuity, joint effusion, and rotator cuff tear as well as CSE images. Our results suggest that the FSE technique is not equal to the CSE technique but can be used for the diagnosis of rotator cuff tears.

Adolescent↗

PubMedDate not supplied

Central neurocytoma with clinically malignant behavior.

We describe two cases of central neurocytoma that did not show histopathologic features of anaplasia but did show tumor dissemination after surgery and radiation therapy. CT and MR imaging before surgery depicted extraventricular extension of the tumors. The importance of radiologic findings is stressed.

Adult↗

PubMedDate not supplied

Chemoembolization of maxillary tumors via the superficial temporal artery using a coaxial catheter system.

A preliminary experience of embolization of maxillary tumors via the superficial temporal artery using a coaxial catheter system is presented. Five patients with maxillary carcinoma were slated to undergo embolization before radical surgery. Embolization with carboplatine microcapsules was performed via the superficial temporal artery using a coaxial catheter system. Carboplatine microcapsules consisted of 60% (W/W) carboplatine core and 40% (W/W) ethylcellulose shell. Embolization was performed twice in three patients, three times in one patient, and once in one patient. The interval between embolizations was from one to three weeks. The total dose of carboplatine microcapsules given ranged from 100 to 230 mg. Responses to the treatment were determined by measurements of tumor reduction and increase in low attenuation areas of the tumor on postcontrast CT. Tumor reduction over 48% was achieved in four of five tumors. All the tumors showed an increased area of low attenuation in the tumor on the postcontrast CT after embolization. No significant complications occurred. This method makes it easy to superselectively repeat embolization.

Aged↗