Dose reduction at CT of the lumbar spine using a 320-detector row scanner: initial results

Purpose. To compare radiation dose and image quality for CT of the lumbar spine between helical CT and wide volume mode scanning with a 320-detector row CT. Patients and methods. Monocenter prospective study on 20 consecutive patients divided into two groups. All 20 patients underwent lumbar spine CT on the 320-detector row scanner (Aquilion One, Toshiba). The CT examinations for group I were performed using the wide volume mode with 320 detector rows while the CT examinations for group 2 were performed using a 64-detector row helical CT mode. The acquisition length and delivered close corresponding to the DLPe (extended close length product) as well as qualitative and quantitative image quality were compared between both groups. Results. The mean acquisition length was comparable between both groups. There was a significant close reduction of about 35% for group I compared to group 2 (mean DLPe of 970 mGy.cm for group I compared to 1503 mGy.cm for group 2, p<0.028) when using the wide volume mode acquisition at 320-detector row CT compared to the 64-detector row helical CT mode. No significant difference was noted for image quality between both groups. Conclusion. The acquisition of lumbar CT using the wide volume mode at 320-detector row CT allows significant dose reduction to patients compared to the 64-detector row helical CT mode while preserving image quality.