Publication

Noise-optimized advanced image-based virtual monoenergetic imaging for improved visualization of lung cancer: Comparison with traditional virtual monoenergetic imaging

Journal Paper/Review - Dec 29, 2015

Units
PubMed
Doi

Citation
Frellesen C, Vogl T, Lehnert T, Kerl J, Bauer R, Metzger S, Albrecht M, Scholtz J, Hüsers K, Wichmann J, Kaup M, Bodelle B. Noise-optimized advanced image-based virtual monoenergetic imaging for improved visualization of lung cancer: Comparison with traditional virtual monoenergetic imaging. Eur J Radiol 2015; 85:665-72.
Type
Journal Paper/Review (English)
Journal
Eur J Radiol 2015; 85
Publication Date
Dec 29, 2015
Issn Electronic
1872-7727
Pages
665-72
Brief description/objective

PURPOSE
To assess the effect of a noise-optimized image-based virtual monoenergetic imaging (VMI+) algorithm in direct comparison with the traditional VMI technique and standard linearly-blended images emulating 120-kVp acquisition (M_0.3) on image quality at dual-energy CT in patients with lung cancer.

MATERIALS AND METHODS
Dual-source dual-energy CT examinations of 48 patients with biopsy-proven primary (n=31) or recurrent (n=20) lung cancer were evaluated. Images were reconstructed as M_0.3, and VMI+ and traditional VMI series at 40, 55, and 70keV. Attenuation of tumor, descending aorta, pulmonary trunk, latissimus muscle, and noise were measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used by three observers to subjectively evaluate general image impression, tumor delineation, image sharpness, and image noise.

RESULTS
Background noise was consistently lower with VMI+ compared to VMI at all keV levels (all p<0.0001) and M_0.3 (all p≤0.0004). Tumor SNR and CNR peaked in the 40keV VMI+ series, significantly higher compared to all VMI and M_0.3 series (all p<0.0008). Observers preferred the 55keV VMI+ series regarding general image impression and tumor delineation compared to all other series (all p<0.0001). Image sharpness and image noise ratings were highest in the 55keV VMI+ and 70keV VMI and VMI+ reconstructions.

CONCLUSIONS
Tumor CNR peaked at 40keV VMI+ while observers preferred 55keV VMI+ series overall other series for dual-energy CT of lung cancer. The noise-optimized VMI+ technique showed significantly lower background noise and higher SNR and CNR compared to the traditional VMI technique at matching keV levels.