The role of spectral CT for the evaluation of renal lesions
Number:28ESURABS0121
Type:Educational Electronic Presentation
Authors: Carmelo Sofia, Maria Adele Marino, Francesco Marcello Arico', Nicola Migliaccio, Antonino Cattafi, Giorgio Ascenti
Keywords:kidney lesions , spectral ct, dual energy ct
SECTIONS
Educational objective

To show the main applications of Spectral Computed Tomography for the evaluation of renal lesions.

Topic Review

LIMITS OF STANDARD CT

Standard computed tomography (CT) scanners are able to distinguish different tissues based on their attenuation, conventionally measured in Hounsfield Units (HU). Tissue attenuation value is a function of X-ray energy.  Since Hounsfield numbers result from polychromatic X-ray beam, they can hide pitfalls.

Pseudo-enhancement, equivocal enhancement and attenuation value overlaps are challenges that every radiologist have to face during clinical daily practice, especially in the evaluation of renal lesions.

Pseudo-enhancement
Pseudo-enhancement is an artifact characterized by an inaccurate increased density of a lesion surrounded by high enhanced tissue after contrast medium injection. This phenomenon depends on a combination of partial volume averaging, beam hardening and scatter radiation and it...

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Fig. 1. Axial True Non-Contrast (A), Conventional Arterial Phase (B) and Virtual Non-Contrast (C) CT images of a cystic renal mass Bosniak II type. Note the calcified septa well-identified on the TNC as well as on the VNC images.
Fig. 2 A-B. Sagital true non-contrast (A) and arterial phase (B) CT images of a pathologically-proven Papillary Renal Cell Carcinoma. Note the equivocal enhancement of the solid renal mass on the arterial phase (Δ HU < 20) .
Conclusions

Spectral computed tomography represents an effective modality for the evaluation of patients having renal lesions, yielding more accurate information on tissue vascularization compared to standard HU evaluation, with reduction of radiation dose and contrast medium volume injected.