Fig. 16.

Infection/abscesses: increased conspicuity at lower keV. A 65-year-old-male patient presented with a neck mass and a c-reactive protein of 180 μg/ml one week after carotid endarteriectomy. Mixed/blended imaging showed right-sided swelling of the neck (a). Anterior of the sternocleidomastoid muscle, a fluid collection was visible, without obvious rim enhancement at mixed imaging. b–d The virtual mono-energetic reconstructions of 40 (b), 55 (c), and 70 (d) keV. At higher keV, SNR was increased, but showed decrease of lesion conspicuity. At 40 keV, the lesion conspicuity and rim enhancement of the lesion were most optimal and suggestive of abscess formation. Small air bubbles were visible at the anterior part of the lesion