Effect of Spectral CT on Tumor Microvascular Angiogenesis in Renal Cell Carcinoma

Abstract Background: To examine the value of spectral CT quantitative parameters in renal cell carcinoma (RCC) microvascular angiogenesis.Methods: The authors evaluated 32 patients with pathologically confirmed RCC who underwent triple-phase contrast-enhanced CT with spectral CT imaging mode from January 2017 to December 2019. Quantitative parameters including the parameters derived from iodine concentration (IC) and water concentration (WC) of 120 keV monochromatic images. The microvascular density (MVD), microvascular area (MVA) and etc. al. of specimens were evaluated. The correlation between IC and WC (including average values and random values) with microvascular parameters were analyzed using Pearson or Spearman rank correlation coefficients.Results: The MVD of all tumors was 26.00 (15.00-43.75) vessels per field at ×400 magnification. The MVD of RCC correlated positively with the mean IC, mean WC, mean NWC, mean NIC, random IC, random NIC in renal cortical phase, WCD1, WCD2, NWCD2 and ICD1 (Spearman rank correlation coefficients, r range, 0.362–0.533; all p < 0.05). The MVA of all tumors was (16.16±8.98) % per field at ×400 magnification. The MVA of RCC correlated positively with the mean IC, mean WC, mean NWC, mean NIC, random IC, random NIC in renal cortical, mean WC and mean NWC in renal parenchymal phase, WCD1, WCD2, WCD3, NWCD2, and NWCD3 (Pearson or Spearman rank correlation coefficients, r range, 0.357–0.576; all p < 0.05). Microvascular grading correlated positively with the mean NWC, mean NIC and random NIC in renal cortical phase, mean NWC in renal parenchymal phase, NWCD2, WCD3, NWCD3, NICD2 and NICD3 (Spearman rank correlation coefficients, r range, 0.367–0.520; all p < 0.05). As for tumor diameter (55.19±19.15), μm, only NWCD3 was associated with it (Spearman rank correlation coefficients, r = 0.388; p < 0.05). Conclusions: IC and WC indexes derived from spectral CT, especially the renal cortical phase, difference between renal cortical phase and parenchymal phase were useful indicators for evaluating tumor angiogenesis. Moreover, the difference of the derived parameters of WC in different phases has stronger correlation with tumor angiogenesis than that of IC.