Radiomic analysis based on multi-phase magnetic resonance imaging to predict preoperatively microvascular invasion in hepatocellular carcinoma

Figure 1 Flowchart of study selection process. HCC: Hepatocellular carcinoma; MVI: Microvascular invasion.

Figure 2 Hepatocellular carcinoma without microvascular invasion in a 60-year-old man. A: The lesion showed slightly high signal intensity on T2-weighted imaging (T2WI) and was first regions of interest segmented; B: T1WI showed hypointensity; C: Hyper-enhancement in the arterial phase; D: The lesion showed wash-out in the portal venous phase; E: Histogram map derived from the portal venous phase.

Figure 3 Hepatocellular carcinoma with microvascular invasion in a 68-year-old woman. A: The lesion also showed slightly high signal intensity on T2-weighted imaging (T2WI) and was segmented; B: T1WI showed hypointensity; C: Hyper-enhancement in the arterial phase; D: The lesion showed wash-out in the portal venous phase; E: Histogram map derived from the portal venous phase indicating that the parameter of histogram was significantly different between the two groups.

Figure 4 Similar histogram features but different most discriminant factors. A: Hepatocellular carcinoma without microvascular invasion and the feature derived from the portal venous phase (PVP); B: Hepatocellular carcinoma with microvascular invasion and features derived from the PVP. Case B showed similar histogram features but different most discriminant factors (MDF) compared with case A; C: Hepatocellular carcinoma without microvascular invasion and features derived from the arterial phase (AP); D: Hepatocellular carcinoma with microvascular invasion and features derived from the AP. Case D showed similar histogram features but different MDF compared with case C.

Figure 5 Hepatocellular carcinoma with microvascular invasion in a 47-year-old man. A: Gd-enhanced arterial phase magnetic resonance imaging showed arterial rim enhancement (arrow); B: Hepatobiliary phase image showing peritumoral hypointensity (arrow).

Figure 6 Area under the receiver operating characteristic curve of the final model. A: Receiver operating characteristic (ROC) curves of the selected model and the ROC curve of the 5-fold cross-validation; B: Nomogram of the integrated model. Hepatobiliary phase (HBP) means peritumoral hypointensity in the HBP, most discriminant factor (MDF)_AP means the MDF of the arterial phase, and MDF_PVP means the MDF of the portal venous phase; C: Comparison of ROC curves for prediction of microvascular invasion. The area under the ROC curve (AUC) was largest for the MDF_PVP alone (AUC = 0.881). ARE: Arterial rim enhancement; MTD: Maximum tumor diameter; PHOH: Peritumoral hypointensity in the HBP; TM: Tumor margin.