European journal of radiology open · 2026
Spatial non-uniformity of liver virtual non-contrast attenuation on dual-layer spectral CT: Impact of body habitus and peripheral right-lobe error.
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Valek Vlastimil, Rohan Tomas, Pecinkova Katerina, Andrasina Tomas
Аннотация
PURPOSE: To evaluate the global and spatial accuracy of virtual non-contrast (VNC) liver attenuation derived from dual-layer spectral CT and its association with patient body habitus.
METHODS: This retrospective single-center study included 99 patients examined with true non-contrast (TNC) and three post-contrast phases on dual-layer CT. Global TNC-VNC agreement was assessed in liver segments S2, S7, and S8. Detailed center-to-periphery analysis in segments S7 and S8 was performed in 87 patients. Spatial non-uniformity was quantified using the spatial error gradient (SEG), defined as the difference between peripheral and central absolute VNC error.
RESULTS: Median absolute whole-liver TNC-VNC differences were 3.0 HU in the arterial phase, 4.4 HU in the portal venous phase, and 3.1 HU in the delayed phase. Peripheral VNC error exceeded central error in all phases; the largest difference was observed in the portal venous phase (4.4 vs 2.3 HU), with a corresponding SEG of 2.4 HU (p < 0.001). Abdominal effective diameter showed a weak but statistically significant correlation with SEG in the portal venous and delayed phases (both p = 0.004). In an exploratory ROC analysis, effective diameter predicted elevated peripheral error with an AUC of 0.746.
CONCLUSION: Dual-layer CT-derived VNC images showed good overall agreement with TNC, but exhibited a population-level tendency toward spatial non-uniformity, with peripheral error exceeding central error. Based on these exploratory data, in evaluation of diffuse liver attenuation, central liver measurements may be preferred over peripheral measurements in larger patients.
METHODS: This retrospective single-center study included 99 patients examined with true non-contrast (TNC) and three post-contrast phases on dual-layer CT. Global TNC-VNC agreement was assessed in liver segments S2, S7, and S8. Detailed center-to-periphery analysis in segments S7 and S8 was performed in 87 patients. Spatial non-uniformity was quantified using the spatial error gradient (SEG), defined as the difference between peripheral and central absolute VNC error.
RESULTS: Median absolute whole-liver TNC-VNC differences were 3.0 HU in the arterial phase, 4.4 HU in the portal venous phase, and 3.1 HU in the delayed phase. Peripheral VNC error exceeded central error in all phases; the largest difference was observed in the portal venous phase (4.4 vs 2.3 HU), with a corresponding SEG of 2.4 HU (p < 0.001). Abdominal effective diameter showed a weak but statistically significant correlation with SEG in the portal venous and delayed phases (both p = 0.004). In an exploratory ROC analysis, effective diameter predicted elevated peripheral error with an AUC of 0.746.
CONCLUSION: Dual-layer CT-derived VNC images showed good overall agreement with TNC, but exhibited a population-level tendency toward spatial non-uniformity, with peripheral error exceeding central error. Based on these exploratory data, in evaluation of diffuse liver attenuation, central liver measurements may be preferred over peripheral measurements in larger patients.