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Table 4 Dose and noise evaluationa

From: Low-dose CT for quantitative analysis in acute respiratory distress syndrome

Measurement 140 mAs 60 mAs 15 mAs 7.5 mAs P-value
CTDIvol (mGy) 22.1 ± 0.0 9.2 ± 0.8 2.2 ± 0.3 1.1 ± 0.1 <0.001
DLP (mGy/cm) 870.5 ± 47.7 362.2 ± 45.2 96.5 ± 39.0 44.9 ± 6.4 <0.001
E (mSv) 17.8 ± 1.0 7.4 ± 0.9 2.0 ± 0.8 0.9 ± 0.1 <0.001
Image noise (HU) 10.0 ± 1.1 15.9 ± 3.5 37.5 ± 10.6 73.8 ± 17.5 <0.001
  1. aCTDIvol = volume computed tomography dose index; DLP = dose-length product; E = effective dose; HU = Hounsfield unit; Image noise = image noise of each applied mAs calculated as the mean SD of tissue density (expressed in HUs) of ten regions of interest placed on a uniform tissue (aorta) in ten different scans; mAs: tube current-exposure time product; mSv = millisievert; P = P-value of one-way analysis of variance. Data are expressed as mean ± SD.