Biomedical subjects

Norihiko Yoshimura

Publications and source records attributed to Norihiko Yoshimura.

5 recordsLinked to original sources

PubMed2006

Correlation between image noise and body weight in coronary CTA with 16-row MDCT.

RATIONALE AND OBJECTIVES: To evaluate the correlation between image noise and body weight (BW) or body mass index (BMI) in coronary computed tomography angiography (CTA) as a potential parameter for reducing radiation dose in coronary CTA. MATERIALS AND METHODS: Thirty-six patients who underwent electrocardiogram-gated cardiac CT were analyzed in this study. The patients included 26 men and 10 women with a mean age of 60 years (range 43-79 years). All patients were imaged on a 16-row multidetector CT scanner. Mean value of BW and BMI was 83.5 kg and 28.1, respectively. Image noise was defined as standard deviation (SD) of the attenuation values measured by using 1 cm2 circular region of interest in the ascending aorta at the level of the right main pulmonary artery. The SD values were plotted against BW and BMI. The correlations were examined using a linear regression method. A P value of less than .05 was considered significant. RESULTS: The r value of linear regression between noise and BW was 0.90 (P < .001). The r value of linear regression between noise and BMI was 0.74 (P = .015). CONCLUSIONS: Excellent correlation was observed between noise and BW in coronary CTA. These data may be used as potential parameters for customized radiation dose modification to reduce radiation dose in coronary CT examinations.

Adult↗

PubMed2005

Two-phase CT pulmonary angiography for detection of hilar pulmonary thromboembolism.

PURPOSE: To assess the usefulness of two-phase CT pulmonary angiography (CTPA) for patients with suspected pulmonary thromboembolism (PE). MATERIALS AND METHODS: Forty-four patients (in 48 studies) underwent two-phase CTPA. Fifteen sec after the injection of contrast material, an entire thorax scan was performed, and in the second phase the hilar territory was rescanned after a 15-sec delay. In the first phase, 25 subjects were scanned cranio-caudally (group A), and 23 caudal-cranially (group B). The mean attenuation values of the main pulmonary artery (MPA) and the ascending aorta (Ao) were measured. Perivenous artifacts in the right pulmonary artery (RPA) were also graded using a 4-point scale. RESULTS: The mean attenuation values in the MPA and Ao were higher in the first phase than in the second phase. The perivenous artifact scores at the first phase in groups A and B were severe in 12 and 15, moderate in 8 and 7, minimal in 4 and 1, and none in 1 and 0. The scores at the second phase were none in all cases. CONCLUSION: Two-phase CTPA produced good opacification of the RPA without major perivenous artifact and proved useful in the detection of PE in these areas.

Adult↗

PubMed2002

Urokinase lysis for acute left subclavian artery thrombosis after placement of infusion catheter: report of two cases.

We present two cases of acute subclavian and/or axillary arterial occlusion after transaxillary catheterization with an implantable port for hepatic arterial infusion chemotherapy. They were successfully treated with thrombolytic therapy using intraarterial administration of urokinase without removal of the infusion catheter system. We consider that this treatment is suitable for managing acute thrombosis of the conduit artery after catheterization for hepatic arterial infusion chemotherapy.

Aged↗

PubMedDate not supplied

Endovascular treatment of spontaneous isolated dissecting aneurysm of the superior mesenteric artery using stent-assisted coil embolization.

Spontaneous isolated dissecting aneurysm of the main trunk of the superior mesenteric artery is a rare condition. We treated a patient with this condition successfully by stent-assisted coil embolization. Intravascular stent placement may widen the indications for endovascular coiling of the aneurysmal false lumen to avoid perforation.

Aortic Dissection↗

PubMedDate not supplied

3-dimensional adaptive raw-data filter: evaluation in low dose chest multidetector-row computed tomography.

OBJECTIVES: To evaluate a 3-dimensional adaptive raw-data filter in reducing streak artifacts in low dose chest computed tomographic (CT) images. METHODS: Fourteen adult patients who underwent low dose chest CT examination (parameters: 25 or 50 mAs, 120 kV) on 64-detector CTscanner were included in this study. We prepared 2 sets of contiguous 5-mm thick images by reconstruction with and without 3-dimensional adaptive raw-data filter (filter-processed and unprocessed images). Streak artifacts and visualization of peripheral vessels in both filter-processed and unprocessed images were evaluated using a 5-point scale. Upper, middle, and lower thorax were evaluated separately. RESULTS: The difference in artifact severity was statistically significant in upper and lower thorax (P = 0.002 and 0.03, respectively), whereas it was not significant in middle thorax (P = 0.13). The difference in the visibility of peripheral pulmonary vessels was not statistically significant in all anatomical regions. CONCLUSIONS: The 3-dimensional adaptive raw-data filter reduced streak artifacts in low dose chest CT in upper and lower thorax.

Adult↗