Contrast monitoring techniques in CT pulmonary angiography: An important and underappreciated contributor to breast dose

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• 作者：D.P. Mitchell ; ^{dpmmitchell@gmail.com} ; ^{dmitchell@mater.ie} ; M. Rowan ^{mrowan@mater.ie} ; E. Loughman ^{eloughman@mater.ie} ; C.A. Ridge ^{cridge@mater.ie} ; P.J. MacMahon ^{pmacmahon@mater.ie}
• 关键词：AA ; ascending aorta ; BMI ; body mass index ; CNR ; contrast to noise ratio ; CTDIVOL ; CT dose index volume ; CTPA ; CT pulmonary angiography ; CXR ; chest X-ray ; DLP ; dose length product ; ED ; effective dose ; HU ; hounsfield unit ; kV ; peak kilovoltage ; LD ; latissimus dorsi muscle ; mA ; tube current ; MPA ; main pulmonary artery ; PE ; pulmonary embolism ; RA ; right atrium ; ROI ; region of interest ; SD ; standard deviation ; SNR ; signal to noise ratio
• 刊名：European Journal of Radiology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：86
• 期：Complete
• 页码：184-189
• 全文大小：813 K
• 卷排序：86

文摘

The aims of our study were to evaluate the contribution of contrast-monitoring techniques to breast dose in pregnant and non-pregnant women, and to investigate the effect of a reduced peak kilovoltage (kV) monitoring scan protocol on breast dose and Computed Tomography Pulmonary Angiography (CTPA) diagnostic quality.Materials and methodsSingle center retrospective study of 221 female patients undergoing a reduced kV 80 kV contrast-monitoring CTPA protocol compared to 281 patients using the conventional 120 kV contrast-monitoring protocol (Siemens Somatom Definition AS + ). 99 pregnant patients analyzed separately. ImPACT dosimetry software was used to calculate dose. Group subsets were evaluated to assess CTPA diagnostic quality.ResultsThe contrast-monitoring component of a CTPA study constituted 27% of the overall breast dose when using a standard 120 kV protocol compared to only 7% of the overall breast dose in the 80 kV study group. The dose to the breast from the contrast-monitoring component alone was reduced by 79% in the non-pregnant patients (0.36mGy ± 0.37 versus 1.7mGy ± 1.02; p < 0.001), and by 88% in the pregnant population (0.25 mGy ± 0.67 versus 2.24mGy ± 1.61; p < 0.001). There was no statistical difference in CTPA diagnostic quality or timing.ConclusionDespite a short scan length and relatively small DLP, contrast-monitoring techniques (test-bolus or bolus-tracked) set at 120 kV can account for 27% of the overall breast dose accrued from a CTPA study. By decreasing the kilovoltage of the contrast-monitoring component, a significant reduction in breast dose for pregnant and non-pregnant female patients can be achieved without affecting CTPA quality or timing.