Harald Marcel Bonel | PubMed Health

PubMed2006

A novel multiple-trauma CT-scanning protocol using patient repositioning.

Emergency CT examination is considered to be a trade-off between a short scan time and the acceptance of artifacts. This study evaluates the influence of patient repositioning on artifacts and scan time. Eighty-three consecutive multiple-trauma patients were included in this prospective study. Patients were examined without repositioning (group 1, n=39) or with patient rotation to feet-first with arms raised for scanning the chest and abdomen/pelvis (group 2, n=44). The mean scan time was 21 min in group 1 and 25 min in group 2 (P=0.01). The mean repositioning time in group 2 was 8 min. Significantly, more artifacts were observed in group 1 (with a repeated scan in 7%) than in group 2 (P=0.0001). This novel multiple- trauma CT-scanning protocol with patient repositioning achieves a higher image quality with significantly fewer artifacts than without repositioning but increases scan time slightly.

Adolescent↗

PubMed2005

Optimization of MDCT of the wrist to achieve diagnostic image quality with minimum radiation exposure.

OBJECTIVE: This study tests various acquisition and reconstruction protocols for MDCT of the wrist to determine the optimal protocol for obtaining diagnostic image quality with minimal radiation exposure. MATERIALS AND METHODS: Thirty anatomic specimens were examined with an MDCT collimation of 4.0 x 1.0 mm and 2.0 x 0.5 mm (80, 120, and 140 kV; 80, 100, 130, 160, and 200 mA; rotation time, 0.5 0.75, 1.0 sec; pitch, 1.0, 1.3, 1.5, and 2.0). Coronal images were reconstructed using a slice thickness of 0.5, 1.0, and 2.0 mm with 60% overlap. Three observers evaluated all images independently for gross and fine anatomic detail. Diagnostic confidence was tested using Shrout-Fleiss intraclass correlation coefficients. Interobserver agreement was assessed by Kappa statistics and the Kruskal-Wallis test. RESULTS: Fine anatomic detail was best presented in 0.5-mm or 1.00-mm reconstructions based on a 2.0 x 0.5 mm acquisition. A rotation time of > or = 0.75 sec resulted in fewer artifacts; a significant dose reduction was achieved with 80 kV and 100 mA at the expense of somewhat increased noise, but without significant loss of anatomic detail in bone presentation. Artifacts were tolerable with a pitch of 1.5 or less. CONCLUSION: MDCT at the described optimal settings allows significant dosage reduction without sacrificing image quality. An acquisition and reconstruction thickness of 0.5 mm results in the best depiction of anatomic detail. A reconstruction thickness of 1.0 mm with a reconstruction interval of 0.5 mm represents a good trade-off between noise and resolution when using low-dose protocols.

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