[Accuracy Verification for Slice Sensitivity Profile Measurement Method by Averaging the Multiple Tilted Wires in Computed Tomography Image].

PURPOSE: Several studies present the unsuitability of the tilted-wire method for slice sensitivity profile (SSP) in helical scan. We compared the accuracy for SSP by the tilted-wire averaging method using multiple wire profiles and by the conventional micro-coin method. METHODS: A micro-coin phantom positioned at the center or the off-center was scanned using a 64-detector row CT scanner in different positions where an X-ray tube starts scanning. In the same way, tilted-wire averaging phantoms, approximately 70 mm in diameter, in the shape of a donut, 8 wires tilted from the circumference toward the center, were scanned. Images were reconstructed with a slice thickness of 0.5 mm. RESULTS: The relative errors of full width at half maximum (FWHM) by the tilted-wire averaging method were -0.015 mm to -0.004 mm (-1.98% to -0.56%) at the center compared to those by the micro-coin method, and it is almost the same value regardless of the number of wires. Relative errors were 0.001 mm to 0.029 mm (0.11% to 3.74%) at the upper 8 cm from the center, and 0.014 mm to 0.078 mm (1.86% to 10.25%) at the upper 16 cm, and the value of relative errors increased as it got farther from the center and as the number of wires went fewer. CONCLUSION: This study indicated that accurate measurement of SSP may be achieved by using 4 (arranged every 90 degrees) or more averaging wires.

Impact of Number of Drugs on Rehabilitation Outcomes in Patients after Traumatic Brain Injury: A Retrospective Cohort Study.

OBJECTIVE: To investigate the impact of the number of drugs on rehabilitation outcomes for patients with acute traumatic brain injury. DESIGN: Retrospective cohort study. SETTING: Hospital-based database created by the Japan Medical Data Center. PARTICIPANTS: Patients with acute traumatic brain injury admitted between April 2014 and November 2017. METHODS: Analysis of relationships among 1-5 and ≥ 6 drugs as well as clinical outcomes in 2603 patients. MAIN OUTCOME MEASUREMENTS: The primary outcome was defined as the Barthel index efficiency, and the secondary outcome was Barthel index gain and length of hospital stay. RESULTS: Median Barthel index score on admission was 40. Barthel index efficiency and Barthel index gain were significantly higher in the group that had taken 1-5 drugs than in the group that had taken ≥6 drugs on admission (median: 1.19 vs 0.50, 20.0 vs 10.0). Also, the group that had taken 1-5 drugs had a significantly shorter length of hospital stay than in the group that had taken ≥6 drugs on admission (median 11.0 vs 14.0). Moreover, multiple linear regression analysis showed that having taken ≥6 drugs on admission was independently associated with Barthel index efficiency, Barthel index gain, and length of stay. CONCLUSIONS: Taking≥6 drugs for acute traumatic brain injury was associated with lower Barthel index efficiency, lower Barthel index gain, and longer length of stay than taking 1-5 drugs.