Advanced abdominal imaging with dual energy CT is feasible without increasing radiation dose.

BACKGROUND

Dual energy CT (DECT) has proven its potential in oncological imaging. Considering the repeated follow-up examinations, radiation dose should not exceed conventional single energy CT (SECT). Comparison studies on the same scanner with a large number of patients, considering patient geometries and image quality, and exploiting full potential of SECT dose reduction are rare. Purpose of this retrospective study was to compare dose of dual source DECT versus dose-optimized SECT abdominal imaging in clinical routine.

METHODS

One hundred patients (62y (±14)) had either contrast-enhanced SECT including automatic voltage control (44) or DECT (56). CT dose index (CTDIvol), size-specific dose-estimate (SSDE) and dose-length product (DLP) were reported. Image noise (SD) was recorded as mean of three ROIs placed in subcutaneous fat and normalized to dose by [Formula: see text] . For dose-normalized contrast-to-noise ratio (CNRD), mean attenuation of psoas muscle (CTmuscle) and subcutaneous fat (CTfat) were compared by CNRD = (CTmuscle - CTfat)/SDn. Statistical significance was tested with two-sided t-test (α = 0.05).

RESULTS

There was no significant difference (p < 0.05) between DECT and SECT: Mean CTDIvol was 14.2 mGy (±3.9) (DECT) and 14.3 mGy (±4.5) (SECT). Mean DLP was 680 mGycm (±220) (DECT) and 665 mGycm (±231) (SECT). Mean SSDE was 15.7 mGy (±1.9) (DECT) and 16.1 mGy (±2.5) (SECT). Mean SDn was 42.2 (±13.9) HU [Formula: see text] (DECT) and 47.8 (±14.9) HU [Formula: see text] (SECT). Mean CNRD was 3.9 (±1.3) [Formula: see text]. (DECT) and 4.0 (±1.3) [Formula: see text] (SECT).

CONCLUSION

Abdominal DECT is feasible without increasing radiation dose or deteriorating image quality, even compared to dose-optimized SECT including automatic voltage control. Thus DECT can contribute to sophisticated oncological imaging without dose penalty.