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Biomedical subjects

R Takagi

Publications and source records attributed to R Takagi.

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

[Usefulness of multi-plane dynamic subtraction CT (MPDS-CT) for intracranial high density lesions].

We present a new CT technique using the high speed CT scanner in detection and evaluation of temporal and spatial contrast enhancement of intracranial high density lesions. A Multi-Plane Dynamic Subtraction CT (MPDS-CT) was performed in 21 patients with intracranial high density lesions. These lesions consisted of 10 brain tumors, 7 intracerebral hemorrhages and 4 vascular malformations (2 untreated, 2 post embolization). Baseline study was first performed, 5 sequential planes of covering total high density lesions were selected. After obtaining the 5 sequential CT images as mask images, three series of multi-plane dynamic CT were performed for the same 5 planes with a intravenous bolus injection of contrast medium. MPDS-CT images were reconstructed by subtracting dynamic CT images from the mask ones. MPDS-CT were compared with conventional contrast-enhanced CT. MPDS-CT images showed the definite contrast enhancement of high density brain tumors and vascular malformations which were not clearly identified on conventional contrast-enhanced CT images because of calcified or hemorrhagic lesions and embolic materials, enabling us to except enhanced abnormalities with non-enhanced areas such as unusual intracerebral hemorrhages. MPDS-CT will provide us further accurate and objective information and will be greatly helpful for interpreting pathophysiologic condition.

Adult↗
PubMed1996

[A new three-dimensional CT reconstruction method for cerebral arteriovenous malformation: development and clinical evaluation of see-through view method].

The authors developed a new three-dimensional reconstruction method called "See-Through View (STV)" using a spiral CT in evaluating of cerebral arteriovenous malformation (AVM). Spiral CT was performed in eight patients with AVM. STV was obtained by reconstructing with a voxel transmission projection using a double threshold method. In all eight patients, STV images enable us to depict the nidus of AVM from all angles by see-throughing skull bone, evaluating the relationship of the vascular lesions adjacent to other cerebrovascular or skeletal structures. In conclusion, STV will provide us further spatial recognition, and will be greatly helpful for surgical planning.

Adult↗
PubMed1995

[CT analysis of aortic cobwebs in aortic dissection].

Contrast-enhanced CT images in patients with acute or chronic aortic dissection were evaluated for the purpose of determining the clinical usefulness of "aortic cobwebs", which were originally reported by Williams et al. as an anatomical marker of the false lumen. Aortic cobwebs were detected in 13 of 44 cases (30%), demonstrating as low density structures in the false lumen continuing from the intimal flap. The aortic cobwebs were mainly linear in shape, and the size ranged from 5 x 1 to 15 x 3 mm (mean: 9 x 2 mm). Aortic cobwebs were more frequently demonstrated in chronic than in acute cases, and were more often detected in the abdominal aorta. Follow-up CT examinations of the cobwebs revealed no interval change in six cases, disappearance in three cases and thickening in one case. There was no significant correlation between the sequential changes in the cobwebs and dilatation or thrombus formation in the false lumen. Aortic cobwebs seem to represent partially residual bands of the aortic media incompletely sheared from the aortic wall during the initial processes of aortic dissection. These structures are considered to be a reliable anatomic marker and to be useful for CT identification of the false lumen in aortic dissection.

Adult↗
PubMed1995

[Late phase contrast enhanced-CT analysis of thrombosed type aortic dissection].

Seven patients with thrombosed type aortic dissection who underwent both early- and late-phase contrast enhanced (CE)-CT scans were analyzed. The image acquisition of early-phase CE-CT began 30 seconds after the intravenous administration of contrast material at an injection rate of 1.5 ml per second. Late-phase CE-CT began 6 minutes after contrast material injection. The thrombosed false lumens were not enhanced on early-phase CE-CTs in any of the cases. In five of seven cases, on the other hand, false lumens of the descending aorta were enhanced on late-phase images. Late enhancement in the false lumen was roughly divided into two patterns; (1) a crescentic enhancement of the sub-adventitial region (3 cases), and (2) a vague enhancement around the ulcerlike projection (2 cases). The mechanism of late enhancement in the false lumen was not fully elucidated. Although the clinical significance of late enhancement has not yet been established, it will be useful to demonstrate an unstable status of the thrombosed false lumens before organization.

Aged↗
PubMed1994

[Three-dimensional imaging of portal and hepatic veins using helical CT with intravenous injection of contrast medium].

The authors developed a simple new method for obtaining three-dimensional helical CT images that simultaneously depict both the portal and hepatic veins. One hundred ml of contrast medium was injected intravenously, and helical CT was carried out. Three-dimensional venous images were successfully displayed with rotational movement on the CRT monitor. The new method provided high-quality images in which the anatomical relationship between the portal and hepatic venous systems could be clearly visualized. This information was useful in helping angiographers to successfully perform transjugular intrahepatic portosystemic shunt and will be of great value for the presurgical planning of hepatic resection.

Adult↗
PubMed1994

[Usefulness of dynamic subtraction CT for intracranial high density lesions].

Dynamic subtraction CT (DSCT) using a high speed Rotate/Rotate CT Scanner (Toshiba Xforce) was performed on 10 patients with intracranial high density lesions such as brain tumors and vascular malformations. In comparison with conventional contrast enhanced CT, the technique of dynamic subtraction CT enabled us to evaluate more clearly the contrast enhancement of high density lesions and to separate more easily the lesions from hematoma and calcification, which are shown as avascular areas. The results suggest that DSCT is a valuable method for evaluating the contrast enhancement of intracranial high density lesions.

Adult↗
PubMed1994

Angiography of the temporomandibular joint. Description of an experimental technique with initial results.

The vascular supply to the temporomandibular joint is not completely understood. To form a base for advancement in this area we developed a method for experimental angiography of the temporomandibular joint that was applied to fresh temporomandibular joint autopsy specimens. Via the external carotid artery the vessels were infused with a mixture of barium and an acrylic resin. The specimens were sectioned and contact radiographs were obtained. These showed the vascularity of the joint and the surrounding structures with great detail. Most of the vascular supply appears to come from the lateral and medial aspects of the condyle head and from the anterior and posterior disk attachments. The method was applied to both normal and abnormal joints and the results suggest that this method could be used to gather further understanding of the vascularity of the temporomandibular joint relative to disease.

Aged↗
PubMed1994

Effect of bevantolol and propranolol on serum lipids in patients with essential hypertension.

In patients with essential hypertension, the beta-blockers bevantolol or propranolol were administered once or twice a day for twelve weeks to evaluate the effects on blood pressure, and lipid metabolism. Both systolic and diastolic blood pressure decreased significantly in response to both bevantolol and propranolol. The pulse-rate also decreased significantly in both groups. Total cholesterol did not change significantly in both groups. Triglycerides increased significantly in the bevantolol group. HDL cholesterol decreased significantly in the propranolol group. The LDL cholesterol/HDL cholesterol ratio increased significantly in the propranolol group, while no significant increase was observed in the bevantolol group. The apolipoprotein B/A ratio was elevated in the propranolol group. No serious side-effects were noted during the study in both groups. These results indicate that bevantolol is an effective antihypertensive drug with fewer unfavorable effects on lipid metabolism than propranolol.

Adrenergic beta-Antagonists↗
PubMed1993

[CT and MR imaging of post-aortic left brachiocephalic vein].

The usefulness of CT and MR imaging (MRI) for the diagnosis of post-aortic left brachiocephalic vein (PALBV) is discussed. The subjects of the present study consisted of five patients with PALBV, two males and three females, aged four months to sixty years. Chest CT and MRI were performed as a follow-up study of other intrathoracic lesions in two cases, and for further examination of congenital heart diseases in two infant cases. The other patient underwent both CT and MRI to evaluate sporadic chest pain. Therefore, all PALBV were found incidentally. PALBV passes below the aortic arch in front of the trachea, draining the superior vena cava behind the ascending aorta. This finding was particularly well documented on consecutive coronal sections on MRI. In patients with intrathoracic malignant or specific inflammatory lesion, differentiation between PALBV and lymphadenopathy is necessary for treatment. From our experience, marked enhancement on CT and no signal intensity on MRI in PALBV could differentiate this anomaly from mediastinal lymphadenopathy. In two infantile cases with congenital cardiovascular anomalies such as tetralogy of Fallot, right aortic arch and pulmonary arterial stenosis, MRI was found to be superior to CT in demonstrating these anomalies.

Adult↗
PubMed1992

Studies on differentiation-inducing activities of triterpenes.

Differentiation-inducing activity of over 180 extracts of crude drugs and plants was tested using mouse myeloid leukemia cell line (M1). The methanol extracts of clove (Syzygium aromaticum Merrill et Perry, Myrtaceae) showed remarkable induction of differentiation of M1 cells into macrophage-like cells. From the extract, oleanolic acid (1) and crategolic acid (2) were isolated as the active components. We also tested other triterpenes, such as oleananes, ursanes and dammaranes, to investigate the structure-activity relationship. Some triterpene aglycones showed differentiation-inducing activity, but triterpene glycosides showed little activity. Furthermore, the differentiation-inducing activity of these triterpene compounds was tested against human acute promyelocytic leukemia cell line (HL-60).

Animals↗
PubMed1991

[Two cases of traumatic bladder rupture with multiple organ failure].

We report two cases of traumatic bladder rupture complicated by multiple organ failure (MOF). The first patient had an extraperitoneal bladder rupture and right femoral bone fracture, which were treated conservatively. However, intrapelvic abscess and adult respiratory distress syndrome (ARDS) which was caused by fat embolism resulted in MOF. The second patient who had been under treatment for malignant lymphoma for three years had an intraperitoneal bladder rupture with ruptures of spleen, intestine and diaphragm. We closed the defects in the bladder, intestine, diaphragm and performed splenectomy. We also provided suprapubic cystostomy and a urethral catheter. However, wound abscess and hepatic failure occurred postoperatively. She died of MOF 20 days after the operation. We stress that in the treatment of bladder rupture, intensive chemotherapy for infection must be done when there are complications of other visceral injuries.

Accidents, Traffic↗
PubMed1989

[Microvascular architecture of the temporomandibular joint in the adult rabbit as studied by the injection replica SEM method. 1. Rest position of jaws].

Microvascular architecture of the temporomandibular joint (TMJ) was studied three-dimensionally in the rabbit using the vascular casting/scanning electron microscope method. TMJ was found to be a well-vascularized organ with the most dense vascular distribution in the retro-discal region, but no blood vessels were observed in the articular disc. Morphologically the vascular networks in the upper and lower layers of the transitional area of the retro-discal region into the articular disc were different. The upper layer had a coarse, cap-shaped network beneath the synovial membrane of the superior articular space, whereas a fine and flat network was observed in the corresponding region of the lower layer. The capillaries overlying these networks took winding courses and formed hairpin-like loops at the discal ends of the networks in both layers, but the winding arrangement was more conspicuous in the lower layer, whereas the loop formation was more marked in the upper layer. The result indicate that in addition to the range of movement, the upper and lower layers may be functionally different in the production of synovial fluid and nutritional supply.

Animals↗
PubMed1989

[A case of 18 q-syndrome associated with status epilepticus].

A 15-year-old boy with 18 q-syndrome manifesting a status epilepticus is reported. He has been already diagnosed as epilepsy because of grand mal seizures at six months earlier, and abnormal EEG findings. Unilateral status epilepticus developed at 15 years of age, which were characterized by alternative repetition of horizontal nystagmus to the right and clonic convulsion of the right (mainly upper) extremities every several minutes. Ictal EEG showed continuous 2 Hz high voltage slow waves superimposed by spikes and polyspikes which transformed to localized, irregular spike discharges in the left occipital region at the end of the status. The chromosomal study revealed a partial deletion of the long arm of No. 18. He had severe mental retardation, and a typical karyotype for 18 q-syndrome with reduced prominence of the midface region, short stature and whorls on all finger tips. The immaturity of the brain probably relates to this kind of unilateral status epilepticus.

Adolescent↗
PubMed1985

Blood loss with use of the Shaw scalpel for the treatment of oral cancer.

The Shaw scalpel was used in seven radical operations for oral cancer. The amount of bleeding and postoperative exudate and the occurrence of postoperative complications were compared with that from 12 operations performed with the conventional steel scalpel. The blood loss during the radical neck dissection performed with the Shaw scalpel was 39% of the control value, and no blood transfusions were necessary. There was no increase in the amount of postoperative exudate in the Shaw scalpel group compared with the control group. Skin incision with the Shaw scalpel was accompanied by superficial wound dehiscences in three patients, which healed without any treatment.

Adult↗