Fig. 4
From: Material analysis through X-ray attenuation decomposition in spectral computed tomography
Cardiac CT angiography scan of a 71-year-old male patient after open aortic arch repair shows two regions of interest (cyan ROIs in a) with HU value similar to that of contrast-enhanced blood in the aortic arch (magenta ROI in a), suspected for graft leakage. The ROI average and (standard deviation) in the conventional image are 359 (20) HU for the magenta ROI and 349 (21) HU and 313 (40) HU for the cyan ROIs. XAD analyses clearly identifies the magenta ROI as a mixture of iodine and blood and shows that the cyan ROIs do not contain blood with iodine, but are in fact some other material (b) because they reside in a completely different part of the XAD plot. This material turned out to be surgical felt to support sutures.
