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J Hachiya

Publications and source records attributed to J Hachiya.

At least 55 records · Page 3Linked to original sources
PubMed1996

Short communication: MR imaging of fetal brain abnormalities using a HASTE sequence.

HASTE (half-Fourier acquisition single-shot turbo spin echo) is a sequence that enables T2 weighted magnetic resonance (MR) images to be obtained in a few seconds. The purpose of this study was to evaluate the usefulness of this sequence in the diagnosis of fetal cerebral abnormalities. Five fetuses suspected of having cerebral abnormalities on ultrasound examination were studied by MR imaging using the HASTE sequence in utero. We compared the images with post-natal MR images or computed tomography (CT) scans. In four fetuses, the abnormality was diagnosed correctly, and the diagnosis was almost correct in the remaining fetus. This sequence is useful because it provides images of diagnostic quality in a very short scanning time.

Brain↗
PubMed1996

[MR imaging for breast cancer].

The potential role of magnetic resonance (MR) imaging in the diagnosis of breast disease has been investigated since the late 1970s. Conventional MR imaging has not been reliable for diagnosis of breast masses, and so contrast MRI using Gd-DTPA has been performed. In particular the gradient echo (GRE) technique combined with administration Gd-DTPA (i.e., dynamic MRI) improves detection and tissue characterization of breast masses. In recent studies, breast MR imaging has shown up to 100% sensitivity in the detection of breast cancer. On the other hand, its specificity varies between 37% and 98% because of the fact that may benign lesions are also enhanced with many contrast media, similar to breast cancer. To improve the specificity of MR imaging, MR-guiding localization and fine needle aspiration biopsy for breast masses will be necessary. Recently breast conserving therapy has been widely accepted in our country, so we deduce that MRI is useful method for detecting multifocal or multicentric breast cancer.

Adult↗
PubMed1996

Three-dimensional helical CT angiography of skull base meningiomas.

PURPOSE: To describe the findings of skull base meningiomas on three-dimensional CT angiograms obtained with helical scanning and to evaluate the usefulness of this method. METHODS: Fifteen patients who had a meningioma near the skull base were examined with helical CT after receiving an intravenous bolus injection of contrast material. RESULTS: All meningiomas had either a honeycomb (12 patients) or solid (3 patients) pattern of enhancement. Bony structures of the skull base and adjacent major arteries that were displaced or surrounded by tumor were also evident. CONCLUSION: Three-dimensional CT angiography depicts the relationship between skull base meningiomas and neighboring bony and vascular structures clearly, quickly, and with minimal risk to the patient.

Adult↗
PubMed1995

Benefits of arterial reconstruction in claudication.

We conducted a midterm follow-up of 150 claudicants who underwent surgical reconstruction by assessing cumulative patency, survival, and palliation (graft patency in live patients) rates. Eighty-nine claudicants (group I) underwent direct (in situ) proximal revascularization, 33 (group II) had indirect (ex situ) proximal revascularization, while 28 (group III) had distal revascularization. The secondary patency rates at 3 years were 97.5% in group I, 97.0% in group II, and 75.0% in group III, respectively. Only one patient with limb graft thrombosis required below-knee amputation. There were 3 perioperative deaths (2 in group I and 1 in group II). The survival rates at 3 years were 86.0% in group I, 69.5% in group II, and 95.8% in group III, respectively. The palliation rates at 3 years were 84.8% in group I, 70.0% in group II, and 77.9% in group III, respectively. These findings indicate the midterm benefits of supra- and infrainguinal arterial reconstructions, and also suggest that the preoperative assessment of risks in individual patients, the selection of the appropriate operative procedure and graft material, and intensive postoperative follow-up and management of any associated disease are all important aspects in the treatment of claudicants.

Aged↗
PubMed1995

[Clinical application of magnetic resonance angiography for coronary arteries: correlation with conventional angiography and evaluation of imaging time].

Magnetic resonance angiography (MRA) of the coronary arteries is a particularly difficult task because of the small size of the vessels and cardio-respiratory motion. The authors describe a method of performing of ultrafast MRA of the coronary arteries with a standard MR system and body coil. Each image was obtained within a single breath hold by "segmented Turbo FLASH" sequences using an electrocardiography gate. Clinical application was performed in 20 patients with ischemic heart disease, and a comparison was made with conventional coronary angiography. The imaging time was shortened significantly by our methods. The diagnosis was made by at least two different images to avoid false positives. The results indicated a good correlation between MRA and conventional angiography.

Aged↗
PubMed1994

[Experimental study of flow rates in microcatheters using various kinds of contrast materials: comparison of imaging capability by iodine delivery rates].

In order to establish the optimal injection technique for abdominal digital subtraction angiography (DSA), flow rate measurement was performed under various combinations of all the currently available iodinated contrast materials with two types of coaxial microcatheters. In vitro study was done utilizing a plastic model of the abdominal aorta with the tip of the catheter positioned at the presumed proper hepatic artery. A total of 20ml of contrast material was injected by a pressure injector at a rate of 3 ml/sec at 300 or 600 psi, and actual flow volume was measured. Imaging capability was evaluated by calculating iodine delivery rates (IDRs). IDRs were highest in iopamidol 300 mgI/ml and iomeperol 300 mgI/ml, nonionic monomeric contrast materials of medium concentration. The results suggest that the best quality DSA images with injection to the proper hepatic artery using a coaxial microcatheter can be obtained with nonionic monomeric contrast materials of medium concentration.

Angiography, Digital Subtraction↗
PubMed1994

[Calcified false channel wall in aortic dissection].

Chest radiographs and computed tomographic images of 110 patients with chronic aortic dissection were retrospectively reviewed. Among these, calcification of false channel wall was observed in 12 cases (about 10%). Stanford type A dissection was noted in 5 cases and type B in 7 cases. Calcified false channel wall may closely simulate intimal calcification of atherosclerotic aneurysm on chest radiographs and sometimes even on CT. Careful observation of CT images with and without contrast enhancement is helpful to correctly identify the site of calcifications in the false channel wall, true channel wall, and intimal flap in the individual cases. In 3 cases calcification was present mainly in the false channel wall with no or only minimal calcification in the true channel wall. These cases may suggest that the endothelialized false channel lumen may develop atheromatous changes much more rapidly than the true lumen. According to advances in surgical and medical treatment of acute aortic dissection, radiologists may encounter cases of chronic aortic dissection with increasing frequency. Full recognition of this potential pitfall in the diagnosis of aortic dissection is important to avoid confusion.

Aged↗
PubMed1994

Fluid-fluid levels in cavernous hemangioma of soft tissue.

Five cases of cavernous hemangioma with fluid-fluid levels on magnetic resonance imaging and/or computed tomography are reported. The signal characteristics were those of blood and histological analysis of the fluid-fluid levels showed that they were blood-filled cavities in the tumor. Although this finding itself is not specific, it may help in confirming the diagnosis of cavernous hemangioma.

Biomarkers↗
PubMed1992

[Percutaneous transluminal angioplasty of dialysis access shunts].

Sixteen balloon angioplasties were performed in 10 patients with upper-extremity dialysis access shunts. The initial success rate was 80% (12/15). Of the initial successes, 58% (7/12) were patent at six months and 13% (1/8) at one year. In nine cases, repeat PTA was necessary. The mean interval of patency was about four months. The longest interval was two and a half years. The complication of thrombosis of the loop shunt during PTA was successfully treated by fibrinolytic therapy.

Adult↗
PubMed1991

[Fracture of percutaneously inserted IVC filters--two cases of Günther's filter].

During the period from 1988 to 1990, percutaneous insertion of Günther vena caval filters were performed in ten patients in our institution. In two of them, fracture and partial migration of anchoring limbs were observed. Günthter's filter is an attractive device for interventional radiologist because of its technical ease of percutaneous placement and relative stability within the vein. However, our experience suggests that this device is not entirely safe and reliable. The patients should be carefully followed up with a possibility of distal migration in mind. Further structural improvement seems necessary.

Adult↗
PubMed1991

Membranous lipodystrophy: MR imaging appearance of the brain.

Five patients with membranous lipodystrophy (lipomembranous polycystic osteodysplasia with progressive dementia) underwent magnetic resonance (MR) imaging of the brain. T2-weighted MR images showed atrophied cerebral white matter with dilated ventricles; increased signal intensity of the white matter; and decreased signal intensity of the thalamus, putamen, caudate nucleus, and cerebral cortex. Although each single finding is not specific, the combination of the above MR findings when coupled with skeletal lesions strongly suggests this rare disease.

Adult↗
PubMed1991

Determinations of organ doses and effective dose equivalents from computed tomographic examination.

The organ or tissue doses were determined with a phantom measurement for 12 types of CT scanners widely used in Japan. Two types of thermoluminescent dosimeters were used for the dose determinations in a Rando woman phantom. The effective dose equivalents recommended by the International Commission on Radiological Protection were calculated using the measured organ or tissue doses. It was found that the CT scanners currently available give quite different organ or tissue doses. When selecting the optimum technical factors for scanning, therefore, it is important to take into consideration the balance of the image quality and the radiation exposure to patients.

Female↗