Publications (61) View all
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Article: Low radiation dose protocol in cardiac CT with 100 kVp: usefulness of display preset optimization.
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ABSTRACT: To evaluate the radiation dose and image quality of 100 kVp cardiac CT, and the effects of display setting optimization. We randomly assigned 100 patients undergoing cardiac CT to one of following two protocols. Fifty patients underwent our conventional protocol with 120 kVp, and the other 50 patients underwent our low radiation dose protocol with 100 kVp. We compared effective dose (ED); CT number, image noise, and contrast noise ratio (CNR) of ascending aorta at 120 and 100 kVp protocol. We also performed quantitative analysis and qualitative analysis for bitmap image of 120, 100 kVp, and display preset optimization for 100 kVp images. The estimated ED was 48 % lower with the 100 kVp protocol than the 120 kVp protocol (2.8 vs. 5.5 mSv, p < 0.01). There is no significant difference in the CNR between 100 and 120 kVp protocol (18.5 ± 3.6 vs. 18.6 ± 3.8, p = 0.84). Display preset optimization significantly improved image quality of 100 kVp cardiac CT, and there is no significant difference in qualitative analysis and quantitative analysis between 100 kVp scan with optimized display preset and 120 kVp scan (p > 0.05). The 100 kVp scanning with optimized display preset offers almost same image quality at cardiac CT of thin adults under 48 % decreased radiation dose.The international journal of cardiovascular imaging 04/2013; · 2.15 Impact Factor -
Article: Novel contrast-injection protocol for coronary computed tomographic angiography: contrast-injection protocol customized according to the patient's time-attenuation response.
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ABSTRACT: We developed a new individually customized contrast-injection protocol for coronary computed tomography (CT) angiography based on the time-attenuation response in a test bolus, and investigated its clinical applicability. We scanned 60 patients with suspected coronary diseases using a 64-detector CT scanner, who were randomly assigned to one of two protocols. In protocol 1 (P1), we estimated the contrast dose to yield a peak aortic attenuation of 400 HU based on the time-attenuation response to a small test-bolus injection (0.3 ml/kg body weight) delivered over 9 s. Then we administered a customized contrast dose over 9 s. In protocol 2 (P2), the dose was tailored to the patient's body weight; this group received 0.7 ml/kg body weight with an injection duration of 9 s. We compared the two protocols for dose of contrast medium, peak attenuation, variations in attenuation values of the ascending aorta, and the success rate of adequate attenuation (250-350 HU) of the coronary arteries. The contrast dose was significantly smaller in P1 than in P2 (36.9 ± 9.2 vs 43.1 ± 7.0 ml, P < 0.01). Peak aortic attenuation was significantly less under P1 than under P2 (384.1 ± 25.0 vs 413.5 ± 45.7, P < 0.01). The mean variation (standard deviation) of the attenuation values was smaller in P1 than in P2 (25.0 vs 45.7, P < 0.01). The success rate of adequate attenuation of the coronary arteries was significantly higher with P1 than with P2 (85.0 vs 65.8 %, P < 0.01). P1 facilitated a reduction in the contrast dose, reduced the individual variations in peak aortic attenuation, and achieved optimal coronary CT attenuation (250-350 HU) more frequently than P2.Heart and Vessels 03/2013; · 2.05 Impact Factor -
Article: Contrast Enhancement During Hepatic Computed Tomography: Effect of Total Body Weight, Height, Body Mass Index, Blood Volume, Lean Body Weight, and Body Surface Area.
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ABSTRACT: OBJECTIVE: The objective of this study was to evaluate the effect of total body weight, height, body mass index, blood volume, lean body weight, and body surface area (BSA) on aortic and hepatic contrast enhancement during hepatic computed tomography (CT). METHODS: We calculated the changes in the CT number per gram of iodine ((Δ Hounsfield units/g [ΔHU/g])) for the aorta and the liver during portal venous phase. We performed linear regression analyses between ΔHU/g and each of the body parameters. RESULTS: ΔHU/g and BSA showed the strongest inverse correlation. The correlation coefficients for the aorta and liver were 0.70 and 0.68 for ΔHU/g and total body weight, 0.41 and 0.37 for height, 0.54 and 0.55 for body mass index, 0.68 and 0.59 for blood volume, 0.70 and 0.62 for lean body weight, and 0.71 and 0.68 for BSA, respectively (P < 0.001 for all). CONCLUSION: Our study supports the use of a protocol with iodine dose adjusted for the patient BSA.Journal of computer assisted tomography 03/2013; 37(2):159-164. · 1.38 Impact Factor -
Article: Low-Contrast Dose Protection Protocol for Diagnostic Computed Tomography in Patients at High-Risk for Contrast-Induced Nephropathy.
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ABSTRACT: OBJECTIVE: To evaluate the safety of a low-contrast dose computed tomography (CT) protocol for patients with renal insufficiency for contrast-induced nephropathy. METHODS: One hundred forty-three patients with renal insufficiency who underwent low-contrast dose-enhanced abdominal CT were reviewed. Another group of 327 patients who received unenhanced CT was reviewed as a control group. Baseline serum creatinine and estimated glomerular filtration rate (eGFR) levels were obtained for all patients to determine the contrast dosing (1.6 and 1.0 mL/kg for patients with eGFR levels 30-59 and 15-29). We compared the incidence of acute kidney injury between the groups. RESULTS: There were no significant differences in the incidence of acute kidney injury between the low-contrast dose and unenhanced CT protocols (9.1% vs 8.3%, P = 0.77). None of the patients with renal dysfunction required postprocedure dialysis. CONCLUSION: The low-contrast dose CT protocol might enable us to perform a contrast-enhanced study without any major safety concerns.Journal of computer assisted tomography 03/2013; 37(2):289-296. · 1.38 Impact Factor -
Article: MR diagnosis of vertebral artery dissection: value of 3D time-of-flight and true fast imaging with steady-state precession fusion imaging.
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ABSTRACT: OBJECTIVES: We hypothesized that 3D time-of-flight (TOF) and true fast imaging with steady-state precession (true-FISP) fusion imaging could provide more information regarding the arterial vessel wall. The purpose of this study was to compare the accuracy of lesion detection and the diagnostic confidence of VAD between TOF images alone and fused TOF and true-FISP images. METHODS: Fifty patients were studied: 17 had VAD and 33 had vertebral artery hypoplasia. Fusion images of the vertebral artery were reconstructed using a workstation. A receiver-operating characteristic (ROC) analysis was conducted with a continuous rating scale from 1 to 100 to compare observer performance in VAD detection. Five radiologists participated in the observer performance test, and their performances with TOF images were compared with those using fused images. RESULT: The observers found that the mean areas under the best-fit ROC curve for TOF images alone and fused TOF images were 0.66 ± 0.05 and 0.93 ± 0.04, which were significantly different (P < 0.01). CONCLUSION: The fusion images provided more information regarding the arterial vessel wall. Fused images aided distinction between vertebral artery dissection versus vertebral artery hypoplasia. KEY POINTS : • New MR techniques can help to differentiate flowing blood from static blood products. • Fused TOF and true-FISP images differentiate the lumen and the arterial wall, improving diagnostic performance. • Fused images may be superior to time-of-flight MR angiography alone.Insights into imaging. 12/2012;
