Affiliation:
1. Ishikawa Clinic, Kyoto
2. Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa
3. Department of Radiology, Osaka City University Graduate School of Medicine, Osaka
4. Oike Clinic, Kyoto
5. Shijyo-karasuma Clinic, Kyoto, Japan
Abstract
Background The effect of flip angle (FA) on synovial fluid and cartilage signal and on image contrast using three-dimensional double-echo steady-state (3D-DESS) sequence have only been performed with 1.0-T but not with 1.5-T or 3.0-T scanners. Purpose To identify the FA that gives the maximum synovial fluid and cartilage values, and to identify the FA at which maximum values of synovial fluid-cartilage contrast-to-noise ratio (CNR) in 3D-DESS sequences when 1.5-T and 3.0-T scanners are used. Material and Methods Using 3D-DESS with water-excitation pulse, mid-sagittal plane images of the knees of 10 healthy volunteers (5 men, 5 women; age range, 21–42 years) were obtained with FA varying from 10° to 90°. Synovial fluid signals, cartilage signals, and background were measured at each FA, and the FA that gave the highest synovial fluid and cartilage values was obtained. Synovial fluid-cartilage CNR was also calculated, and the FA that gave the largest CNR was obtained. Results At 1.5 T, the maximum synovial fluid signal was at FA 90°, and the maximum cartilage signal was at FA 30°. Synovial fluid-cartilage CNR was highest at FA 90° ( P < 0.05). At 3.0 T, the maximum synovial fluid signal was at FA 90°, and the maximum cartilage signal was at FA 20°. Synovial fluid-cartilage CNR was highest at FA 90° ( P < 0.05). Conclusion In order to improve the visibility of cartilage itself, FA settings of 30° at 1.5 T and 20° at 3.0 T are apparently ideal. For observing the cartilage surface, the most effective FA setting is 90° for both 1.5 T and 3.0 T.
Subject
Radiology Nuclear Medicine and imaging,General Medicine,Radiological and Ultrasound Technology
Cited by
9 articles.
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