Biomedical subjects

Y Kihara

Publications and source records attributed to Y Kihara.

172 records · Page 10Linked to original sources

PubMedDate not supplied

Optimal timing for delineation of hepatocellular carcinoma in dynamic CT.

OBJECTIVE: The aim of our study was to ascertain the optimal timing and scanning method for detecting hepatocellular carcinoma (HCC) as a high density mass during the early phase of dynamic hepatic CT and to confirm its clinical effectiveness. MATERIALS AND METHODS: We studied retrospectively 39 patients with clinically diagnosed HCC who underwent dynamic hepatic CT. RESULTS: All nine lesions that were scanned within 60 s after initiating injections were detected as high density masses. However, 15 of 21 lesions (71%) that were scanned > 70 s after initiating injections could not be detected as high density masses. Using helical scanning, which permitted scanning the entire liver within 60 s after initiating injections, 27 of 31 lesions (87%) were detected as high density masses. CONCLUSION: We concluded that most HCCs can be detected as high density masses during the early phase of dynamic CT using helical scanning.

Adult↗

PubMedDate not supplied

Portocaval shunt with unusual CT and MR manifestations.

OBJECTIVE: We investigated the radiological findings of three cases with unusual portocaval shunts. MATERIALS AND METHODS: Three patients with liver cirrhosis and portal hypertension were examined using CT and MRI. CT was performed using intravenous bolus injection of contrast medium in one and with incremental dynamic scanning in two cases. MRI was performed with a 1.5 or 0.5 T superconducting system or with a 0.22 T resistive system in the three patients. RESULTS: CT and MRI showed tortuous intrahepatic tubular structures connecting the right posterior portal vein to the inferior vena cava (IVC) in two of the patients. An anomalous vein arising from the extrahepatic portal vein was a tributary connected with the IVC in one patient. Symptoms associated with hepatic encephalopathy were present in two of the patients whose blood ammonia levels were elevated. CONCLUSION: The possibility of the existence of hepatic encephalopathy should be borne in mind when these shunts are detected during abdominal imaging.

Adult↗

PubMedDate not supplied

Acute hemodynamic effects of a new positive inotropic agent, 3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)- quinolinone (OPC-8212), in conscious and anesthetized dogs.

The acute hemodynamic effects of a new cardiotonic agent, OPC-8212 (a 1H-quinolinone derivative), were studied in six conscious and 11 anesthetized dogs using a pair of ultrasonic crystals to measure the left ventricular segment length and a micromanometer to measure the left ventricular pressure. In six anesthetized dogs subjected to aortic constriction, the ascending aortic flow (AoF) was measured before and after intervention. In the anesthetized state bolus injections of OPC-8212 increased the ejection indices dose dependently. Maximum effects were observed at 1 min, the mean velocity of the circumferential fiber shortening (mean Vcf) being augmented by 6.6% with 0.3 mg, by 39.7% with 1 mg, and by 67.2% with 3 mg. These changes were not accompanied by any significant alteration in heart rate. With aortic constriction, the left ventricular wall shortening was significantly reduced. Depressed pump function was dramatically improved with injection of 3 mg of OPC-8212, the dP/dt was elevated by 98%, the AoF by 46%, and the mean Vcf by 78%. In the conscious state the same doses induced the same type of changes in hemodynamics and dimensions, but the amplitude of the response was significantly less; increase in the mean Vcf was by 36% and that of dP/dt by 52%. Thus, OPC-8212 has a potent inotropic effect. The effect was greater in the anesthetized state, or in dogs with depressed ventricular function, than in the conscious state.

Anesthesia↗

PubMedDate not supplied

A rat model of dilated cardiomyopathy to investigate partial left ventriculectomy.

BACKGROUND: This study is the first to assess a small animal model of dilated cardiomyopathy (DCM) for evaluation of partial left ventriculectomy. METHOD: Eighteen Dahl salt-sensitive (DS) rats were divided into three groups. Six rats were fed an 8% high-salt diet from the age of 7 weeks (Group 1), and similarly six rats from 8 weeks (Group 2) and six from 9 weeks (Group 3). Blood pressure (BP) was measured by the tail-cuff method and left ventricular (LV) dimensions by echocardiography. RESULTS: In Groups 1 and 2, systolic BP rose and reached 200 mmHg by the 10th to 11th week, when all rats died within a week without signs of heart failure. However, in Group 3, systolic BP gradually rose to 196+/-15 mmHg (mean +/- SD) at the age of 14 weeks, when LV end-diastolic diameter (EDD) was 6.2+/-0.4 mm (control 5.1+/-0.7 mm) and LV fractional shortening (FS) was 77+/-3% (control 68+/-3%). At the age of 25 to 30 weeks, all rats in Group 3 showed signs of congestive heart failure, systolic BP remained high, EDD markedly increased (8.7+/-0.6 mm), and LVFS decreased (38.9+/-8.1%). From this stage, rats survived for 13.7+/-5.9 days. We employed the Group 3 model for our pilot PLV study. Eight rats had PLV with a beating heart by plicating the LV area between the papillary muscle bases. Two rats died perioperatively but the rest survived (60% survival 3 weeks after PLV). Postoperatively, the rats' LVEDD decreased and FS improved significantly. CONCLUSIONS: Using DS rats, we developed a DCM model for investigating PLV. The model may contribute to scientific investigation of PLV.

Animals↗

PubMedDate not supplied

Sudomotor dysfunction in amyotrophic lateral sclerosis.

We performed a quantitative sudomotor function test on 11 patients with classic amyotrophic lateral sclerosis (ALS) and 11 age-matched control subjects. Thermal warming increased the sweat rate in the forearm of ALS patients and in the forearm and thigh of control subjects. The sweat rate in the thigh of ALS patients was lower than that of controls. Thyrotropin releasing hormone increased the sweat rate in the forearm and thigh and decreased oral temperature in both ALS and controls but the lower extremity response was reduced in ALS. Results of the sudomotor axon reflex test on the thigh indicate that in ALS, there is mild postganglionic sudomotor dysfunction. We conclude that patients with ALS have mild thermoregulatory sweat dysfunction due to postganglionic lesions in the lower extremities.

Amyotrophic Lateral Sclerosis↗

PubMedDate not supplied

Repositioning of a displaced catheter for percutaneous hepatic arterial infusion chemotherapy.

This is a report of a patient with hepatocellular carcinoma whose hepatic arterial catheter, which was introduced via a subclavian arterial branch, migrated into his right gastric artery. The catheter was successfully maneuvered to a suitable position without any further invasive procedure. The importance of preparatory embolization of the right gastric artery is underscored.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Motion related artifacts in spin-echo MR imaging: effects of sequence parameters on image quality at 1.5 Tesla.

PURPOSE: The purpose of this study was to evaluate the effects of selected parameters in a conventional spin-echo MRI sequence on image quality in a phantom undergoing periodic motion. METHODS: Images of a composite oil/copper sulfate phantom moving in a 1.5 Tesla magnet were acquired. The CuSO4 ghost signal-to-noise ratio (SNR) and distances between corresponding points on the phantom image and adjacent ghosts were evaluated. RESULTS: Increasing time to repeat (TR) and number of acquisitions (NAq) improved image quality. Ghost SNR was near unity at TR = 500 msec and at NAq around 4. Increasing TR and NAq resulted in increased distance between images. The effects of field of view (FOV) and matrix size on image quality were relatively less significant. CONCLUSION: Increasing NAq appeared to have a comparatively greater effect on ghost SNR and image quality under our experimental conditions. However, the effect of increasing NAq on image quality appeared to be definite since a saturation point was reached after a particular NAq. Increasing NAq above this point resulted in a relatively smaller improvement in image quality.

Artifacts↗

PubMedDate not supplied

Adult cystic Wilms' tumor (nephroblastoma): radiologic features with pathologic correlation.

Wilms' tumor is an uncommon disease in adults. Wilms' tumor typically presents as a large complex mass with cystic component and varying degrees of vascularity. The previously reported radiologic findings have reflected this complex appearance. We present a case of cystic Wilms' tumor in an adult patient. The tumor presented as a large, rapidly growing, hypovascular, multicystic mass with minimal solid component which showed as septation on ultrasound, contrast enhanced CT, and MR studies. The preoperative findings were suggestive of multilocular cystic nephroma. We suggest that Wilms' tumor should be included in the differential diagnosis of a patient who presents with a large, rapidly growing, multicystic renal mass.

Adult↗

PubMedDate not supplied

Lipiodolized gelatin sponge: a simple method to make gelatin sponge radiopaque.

Gelatin sponge particles were rendered radiopaque by soaking them in small amounts of iodized oil (LP-GS). They were evaluated for their usefulness in transarterial embolization (TAE). The LP-GS particles were well visualized fluoroscopically during TAE. The duration of the opacity of LP-GS exceeded 24 hours both in vitro and in vivo. LP-GS are useful, and are an easily obtainable, radiopaque, embolic material.

Contrast Media↗

PubMedDate not supplied

Percutaneous transluminal renal angioplasty of arterial divarication: application of kissing balloon technique.

We present a patient with renal artery stenoses due to fibromuscular dysplasia involving the point of arterial bifurcation that we could successfully dilate with percutaneous transluminal angioplasty. We used the kissing balloon technique to prevent possible complications of percutaneous transluminal renal angioplasty (PTRA), including occlusion of the other branch while dilating one branch. The kissing balloon technique worked well for PTRA of the arterial bifurcation.

Adolescent↗