Differentiation of tumor budding grade in colon cancer using noise-optimized virtual monoenergetic image in dual-energy CT.

OBJECTIVE

To evaluate the value of noise-optimized virtual monoenergetic image (VMI+) in dual-energy CT (DECT) in predicting tumor budding (TB) grade in colon cancer.

METHODS

Seventy-six patients with pathologically confirmed colon cancer who underwent contrast-enhanced DECT were retrospectively enrolled and were divided into low/intermediate-grade TB (n = 52) and high-grade TB groups (n = 24). The contrast-to-noise ratio (CNR), overall image quality, and lesion delineation were evaluated on VMI+ (40-0 keV with an interval of 10 keV). The DECT quantitative parameters were analyzed, including attenuation of VMI+, iodine concentration (IC), normalized IC (NIC), electron density (Rho), and effective atomic number (Zeff). The diagnostic performance in differentiating TB grade in colon cancer was evaluated using the area under the curve (AUC).

RESULTS

40 keV, 50 keV, and 60 keV showed good diagnostic performance in differentiating TB grade (AUC: 0.825, 0.833, and 0.843; sensitivity: 0.708, 0.708, and 0.750; specificity: 0.904, 0.904, and 0.846; cutoff value: 179.5 HU, 129.9 HU, and 101.2 HU) and had significantly higher AUC than IC (0.770), NIC (0.647), Rho (0.642), and Zeff (0.785) (all P < 0.05). 40 keV had the best lesion delineation and provided significantly higher CNR than other VMI + levels, while 60 keV provided better overall image quality than other VMI + levels (all corrected P < 0.05).

CONCLUSIONS

The DECT-derived low-keV VMI+ (40 keV, 50 keV, and 60 keV) provided better diagnostic performance in differentiating TB grade in colon cancer. 40 keV showed better CNR and lesion delineation, while 60 keV provided better overall image quality.