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Biomedical subjects

A Heshiki

Publications and source records attributed to A Heshiki.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Three-dimensional MR angiography of aorta with Gd-DTPA infusion and breath-holding].

Using the rapid three-dimensional gradient echo technique (FLASH 18 degrees 10/4) and Gd-DTPA administration, we performed MR angiography (MRA) of the thoracic and abdominal aorta during single or double breath-holding periods. Basic in vitro and in vivo dynamic studies showed that infusion of a relatively low concentration (74 mg Gd/ml) Gd-DTPA solution provided a strong and persistent flow signal for a considerable length of time. Eleven of 12 cases clearly demonstrated MRAs of the aorta and its main branches without respiration-induced motion artifacts, although visualization of secondary and more peripheral branches depended on their size, direction and injection-imaging timing. Although limited spatial resolution and pulsatility-induced ghost artifacts remained as problems to be solved, the ease of this method, short examination time and excellent arteriograms with no need for venous or fat suppression make it clinically acceptable and very promising.

Adult↗
PubMed1994

[Clinical application of three dimensional ultrafast MR imaging to intracerebral traumatic lesions].

We applied a T1-weighted three-dimensional (3D) magnetization-prepared rapid gradient-echo sequence (MPRAGE) for the detection of intracerebral lesions associated with closed head injuries. Thirty-four patients underwent brain MR imaging on a 1.5 Tesla superconducting MR unit. We applied an MPRAGE sequence, together with spin echo (SE) and gradient echo (GRE) sequences, and evaluated the detectability of lesions with each sequence. A total of 100 intracerebral traumatic lesions (33 cortical contusion, 56 diffuse axonal injury, 11 subcortical gray matter injury) were found. Ninety-seven percent of all lesions were detected on MPRAGE images, and 67% on SE and GRE images. The detectability of lesions in each category was 91%, 98%, and 100% on MPRAGE images, and 88%, 54%, and 73% on either SE or GRE images. 3D MPRAGE is a promising method to detect intracerebral traumatic lesions, particularly those associated with diffuse axonal injury, because of its high quality of contrast and spatial resolution and the capability of image reconstruction in any plane.

Adolescent↗
PubMed1994

[Hyaline cartilage delineation of the knee joint using magnetization transfer contrast images].

Using a magnetization transfer contrast method (MTC), we evaluated its clinical feasibility for demonstration of hyaline cartilage of the human knee in five normal subjects. MTC images, obtained from a gradient echo sequence with an off resonance pulse, were compared with those without off resonance pulse. Signal to noise ratio (SNR) and magnetization transfer rate (MTR) were analyzed with respect to hyaline cartilage, muscle, fat, joint fluid and background noise. Also, contrast to noise ratios (CNRs) of cartilage and fluid were compared. MTRs were significantly different between cartilage-muscle group and fat-fluid group. The CNRs of cartilage and fluid were increased on MTC images, showing good contrast separation between hyaline cartilage and joint fluid.

Adolescent↗
PubMed1994

[High resolutional MR angiography of renal arteries with Gd-DTPA infusion and breath-holding].

To obtain high resolutional renal MR angiogram we combined 3D fast scanning technique with Gd-DTPA infusion and surface coil imaging in seven individuals. 1 x 2 x 4 mm spatial resolution provided excellent renal arterial images although thinner slices suffered from decreased signal to noise ratio and ghost artifacts. Twenty seconds interval between injection and data sampling was considered suitable to obtain sufficient signal of the renal arteries. Its easiness, no x-ray irradiation, and capability of repeating study make this technique promising for screening renal arterial diseases.

Adolescent↗
PubMed1992

[2D MR angiography of the aortic aneurysm--effectiveness of oblique saturation pulses for selective angiogram].

2D time-of-flight MR angiography was performed in 6 cases of thoracic aortic aneurysm. Oblique saturation pulses were used to suppress the signals of the pulmonary artery and SVC, providing excellent selective MR aortograms. 3 dimensional extension of the aneurysm and its relation with cervical branches were easily assessed. It could be possible to replace invasive aortography by this technique.

Aorta, Thoracic↗
PubMed1992

Bone marrow MRI in prostate cancer.

Normal bone marrow MRI has a distinct pattern with STIR pulse sequence MRI. The central low signal intensity area corresponds to fatty marrow. The red marrow is distributed in the peripheral portion of the vertebrae and shows a high signal intensity. Prostatic cancer metastases to the bone marrow revealed a high signal intensity with STIR. Prior to the appearance of an abnormal scintigram and radiograph, MRI was able to depict an abnormality.

Adipose Tissue↗
PubMed1991

[Omentum transplantation to the cervical cord with microangioanastomosis].

Transplantation of omentum to the cervical cord was done in three cases with incomplete transection (Case 1) with posttraumatic progressing cervical myelopathy (Case 2) and with complete transection due to multisegmental, late cervical cord infarction (Case 3). Anastomoses were made between the occipital artery and the gastroepiploic artery of transplanting omentum and between the occipital vein and the gastroepiploic vein. In Case 2 and 3, omentum was maintained in tissue culture medium in an incubator (37 degrees C, 5% CO2) for about five hours following perfusion of the omentum with low molecular dextran containing urokinase, heparin, vitamin B12 until exploration of the dural tube and preparation of the occipital vessels were accomplished. Although complete transection with late infarct (Case 3) showed extremely slow improvement in follow-up period of 8 months, the incomplete traumatic lesions (Case 1 and 2) showed less slow but steady improvements in follow-up periods of 24 and 22 months with almost complete recovery of Case 2. Angiography showed patent anastomosis in all the cases. Dynamic CT at 4 (Case 1) and 6 (Case 2) months showed good perfusion in the compromised cord through the transplanted omentum.

Evoked Potentials, Somatosensory↗
PubMed1989

[MR imaging of the bone marrow using short TI IR. Part 1--Normal and pathological intensity distribution of the bone marrow].

Normal vertebral bone marrow intensity distribution and its alteration in various anemias were evaluated on short TI IR sequences. Material consists of 73 individuals, 48 normals and 25 anemic patients excluding neoplastic conditions. All normal and reactive hypercellular bone marrow revealed characteristic intensity distribution; marginal high intensity and central low intensity, corresponding well to normal distribution of red can yellow marrows and their physiological or reactive conversion between red and yellow marrows. Aplastic anemia did not reveal normal intensity distribution presumably due to autonomous condition.

Adolescent↗
PubMed1989

[MR imaging of the bone marrow using short TI IR. Part 2--Normal and pathological intensity distribution of the bone marrow].

Bone marrow pathology of hematological neoplasms was evaluated using short TI IR sequences and T2 weighted STIR (IR 1500/100/40, IR 1500/100/80). Material consisted of 49 individuals including 10 leukemias, 5 myelofibroses and 30 multiple myelomas. On IR 1500/100/40, all cases revealed heterogenously or diffusely high intensity. On IR 1500/100/80, both of acute and chronic myelocytic leukemias revealed definite signal decrease, while chronic lymphocytic leukemia, myelofibrosis and multiple myeloma showed no obvious signal decrease.

Adolescent↗
PubMed1986

Radiological evidence of healing of a simple bone cyst after hole drilling.

We report the long-term results with ten patients with simple bone cysts with special retrospective reference to the radiographic evidence of healing after hole drilling. Cortical thickening was initially observed within 3 months, and minimal new bone formation around Kirschner wires left in situ was observed within 4 months. New bone formation gradually progressed from the cyst wall and around the wire. Consolidation of a cyst cavity was uniformly observed 6-7 months after drilling. In several patients residual cysts were seen between the wire and cortical shell. In younger patients, a cystic cavity reappeared after extraction of the wire, although complete radiographic healing had been observed. These findings suggest that a Kirschner wire plays an important role in preventing relapse of simple bone cysts after hole drilling.

Adolescent↗