PubMed Health⌕ Search

Biomedical subjects

E Takenaka

Publications and source records attributed to E Takenaka.

At least 19 recordsLinked to original sources
PubMed1991

Relocatable Gianturco expandable metallic stents.

The authors modified Gianturco expandable metallic stents to make them relocatable. Two tandem designs were made. The first design had long struts and, thus, more evenly distributed expansive force; the second had short struts and more flexibility and was better suited for use in curved strictures. Both designs (two to four in tandem, 0.012-, 0.014-, and 0.018-inch wire) were tested successfully in vitro, and both designs (two to four in tandem, 0.012-inch wire) were successfully placed, retrieved, and relocated in the inferior vena cava of five dogs.

Animals↗
PubMed1991

Wire-directed detachable balloon. Work in progress.

A new silicone detachable balloon has two self-sealing valves. The proximal valve grips the catheter tip, and the distal valve allows a guide wire to pass through. The balloon is advanced over the guide wire. Detachment is performed after the wire is withdrawn. Five balloons were successfully placed in the intended arteries and veins of three dogs. This wire-directed detachable balloon is placed more easily and accurately than the conventional detachable balloons that are placed with the flow-directed method.

Angiography↗
PubMed1991

Embolization with steel coils using a saline flush technique.

A method using saline flush to push Gianturco steel coils through catheters is described, and has been successfully used in 45 patients. The saline flush technique requires no precise matching of coils and catheters, solves problems associated with the conventional method and simplifies the coil embolization procedure.

Arteries↗
PubMed1990

Hepatic inferior vena cava obstruction: treatment of two types with Gianturco expandable metallic stents.

Gianturco expandable metallic stents were used for treating six patients with inferior vena cava (IVC) obstruction due to compression by large hepatic tumors and three patients with idiopathic obstruction of the hepatic IVC and Budd-Chiari syndrome who showed reocclusion or stenosis 3-21 months after previously performed percutaneous transluminal angioplasty (PTA). In all six patients with compression by hepatic tumors, stents dilated the IVC and debilitating edema of the lower body disappeared. In the three patients with idiopathic obstruction, stents were placed after repeat dilation of the lesions and Budd-Chiari syndrome did not recur during a follow-up period of 7-10 months. In two of the three, cavograms obtained 8 months after placement showed the channels to be open with minimal intimal thickening. Gianturco expandable metallic stents can correct IVC obstruction due to compression by hepatic tumors and are useful in preventing reocclusion of the IVC after PTA for the treatment of idiopathic obstruction. The authors recommend using tanem stents connected by at least two struts.

Aged↗
PubMed1989

Hepatic epithelioid hemangioendothelioma: report of five cases.

Results of computed tomography (CT), ultrasonography (US), angiography, and radionuclide imaging were analyzed in five cases of histologically proved hepatic epithelioid hemangioendothelioma (EHE), a rare vascular tumor of adults that has a variable but often long clinical course. All patients received palliative treatment. CT and US were performed repeatedly over a period of up to 53 months. Initial radiologic examination showed two types of hepatic lesions: multiple nodules in both lobes (nodular lesions, n = 2) and large masses with or without calcifications that generally spread along the hepatic margins (diffuse lesions, n = 3). Nodular lesions may be an earlier form of hepatic EHE, as they later gradually changed into the diffuse type. Follow-up CT after treatment showed definite regression of tumors in two cases. In the differential diagnosis, the radiologic findings of diffuse lesions were considered to be specific to hepatic EHE, while those of nodular lesions were nonspecific.

Adult↗
PubMed1989

[MR findings of metastatic brain tumors].

Fifteen cases with metastatic brain tumor(s) were examined on a 1.5T MR system and the results were evaluated along with images of contrast-enhanced CT. Gd-DTPA-enhanced T1-weighted imaging (T1WI) showed the best detectability of lesions and was followed by contrast-enhanced CT, T2WI, and non-enhanced T1WI in that order. No correlation was found between the MR signal intensity and the histological classification of the tumors. In differential diagnosis with glioblastoma, several signal characteristics were encountered. Low or isointensity as well as the discrimination of tumor from edema on T2WI was considered to suggest the diagnosis of metastatic tumor.

Adult↗
PubMed1989

[Subdural hematoma from ruptured arteriovenous malformation; demonstration by MR imaging].

We studied MRI of 15 cases of arteriovenous malformation (AVM) with special reference on the coexistence of the subdural hematoma. All ruptured cases (6 cases) were associated with intracerebral hematoma, and half (3 cases) of them were coexisted with subdural hematoma. In one of them, the presence of the subdural hematoma promoted us to perform angiography which revealed the AVM.

Adolescent↗
PubMed1988

Hepatic inferior vena cava obstructions: clinical results of treatment with percutaneous transluminal laser-assisted angioplasty.

Three cases of hepatic inferior vena cava (IVC) obstruction (two segmental and one membranous) associated with Budd-Chiari syndrome were successfully treated with percutaneous transluminal angioplasty (PTA) with use of an Nd-YAG (neodymium-yttrium, aluminum, garnet) laser. The occluded portions were canalized by advancing a ceramic-capped delivery system and delivering intermittent laser emissions. The canal was widened by simultaneous inflation of three or four Gruentzig balloon catheters. In two of the three cases, this procedure was done after unsuccessful canalization of the occluded portions by conventional means. Postoperatively, all patients showed disappearance of Budd-Chiari syndrome. One patient also showed marked regression of a huge intraluminal thrombus. There were no serious complications during and after the procedures. Use of the Nd-YAG laser seems to be of value in PTA for the treatment of hepatic IVC obstructions as well as in treatment of arteriosclerotic lesions.

Adult↗
PubMed1988

MR imaging vs CT in subacute sclerosing panencephalitis.

The MR findings in three patients with subacute sclerosing panencephalitis were reviewed and compared with CT findings in the same patients. Long-T2 lesions were demonstrated in each case, although their distribution varied with the clinical stage of the disease. MR, especially T2-weighted imaging, appears to be of great utility in the assessment of subacute sclerosing panencephalitis.

Adolescent↗
PubMed1986

Single photon emission computed tomography of brain tumors with 201TIC1.

Single photon emission computed tomography (SPECT) with 201TIC1 was performed in 27 patients with brain tumors. Findings on SPECT were compared with those on planar images, computed tomography (CT) and, in 4 cases, magnetic resonance imaging (MRI). At SPECT the tumors were shown as areas with higher accumulation of the tracers than the surrounding brain tissue in 24 cases and a better discrimination was obtained than in planar images. Deep-seated lesions were especially visualized. In some cases SPECT defined lesions that were not clearly delineated on CT or MRI. SPECT with 201TlCl can be of clinical use in the diagnosis of brain tumors.

Brain Neoplasms↗
PubMed1986

Synchrotron radiation at the Photon Factory for non-invasive coronary angiography: experimental studies.

Synchrotron radiation available at the Photon Factory, National Laboratory for High Energy Physics, provides a new X-ray source which is highly suitable for K-edge subtraction. This is due to its high intensity, its parallelism and its monochromaticity, available in a monochromator system. Experiments were performed using wiggler synchrotron radiation. Since the beam size is relatively-small for in-vivo imaging, a phantom coupled with a detector was moved horizontally using a scanning table. K-edge subtraction was successfully applied both to the coronary artery phantom filled with barium sulphate, and to rat angiography using iodine contrast material. The potential use and value of energy subtraction was successfully demonstrated.

Animals↗
PubMed1985

Effects of scattered X-rays on CT images.

Scatter to primary radiation ratios at detector positions were calculated for uniform cylindrical water phantoms in both third and fourth generation x-ray CT scanners using the Monte Carlo simulation method. A rapid method for determining the scattering angle is given. In the process of image reconstruction, the effect of scatter was isolated by applying our new calculation technique. The decrease in CT number due to scatter was found to be less than 10. In the third generation CT scanner the rate of scatter is larger at the centre than at the edge because of the effect of the collimator at the detectors. As a result the cupping artefact occurs in the CT image. The collimator cannot be used in the fourth generation CT scanner and, therefore, the rate of scatter is almost uniform, leading to the appearance of rounded-off edges.

Humans↗