Abstract: Objective To explore the value of multimodal imaging quantitative parameters in the differential diagnosis of small hepatocellular carcinoma (SHCC) and dysplastic nodules (DN) on the background of cirrhosis.Methods Eighty patients with cirrhosis and focal space-occupying lesions were divided into SHCC group (46 cases, SHCC) and nodule group (34 cases, DN) according to their pathological diagnosis. Preoperative CT, contrast-enhanced ultrasound (CEUS) and MRI examinations were conducted in both groups of patients. The imaging characteristics of lesions and quantitative parameters were compared between the two groups of patients.Results As shown by CT, the blood flow (BF) (170.37±58.49 vs 143.45±55.24), blood volume (BV) (16.51±5.89 vs 13.12±4.03), mean transit time (MIT) (9.39±2.58 vs 8.12±2.37), surface permeability (PS) (49.30±15.16 vs 42.71±13.28), and hepatic artery fraction (HAF) (59.34±13.70 vs 46.35±11.38) were different between the SHCC group and the nodule group (all P<0.01). As shown by CEUS, the arrival time (AT) (15.23±3.64s vs 19.11±3.08s), time to peak (TTP) (29.63±9.68s vs 62.37±13.65s), peak intensity (PI) (65.19±7.64 vs 55.29±6.81), regional blood volume (RBV) in arterial phase (3367.5±751.7 vs 1458.2±709.8), regional blood flow (RBF) in arterial phase (64.3±18.9 vs 48.2±13.1), regional blood volume (RBV) in delay phase (473.2±155.1 vs 736.5±295) between the SHCC group and the nodule group were also different (all P<0.01). MRI shown that the apparent diffusion coefficient (ADC) {(0.78±0.17)×10^-3 mm²/s vs 1.35±0.39)×10^-3 mm²/s}, pure diffusion coefficient (D) {(0.89±0.21)×10^-3 mm²/s vs (1.17±0.25)×10^-3 mm²/s}, pseudo diffusion coefficient (D*) {(45.14±10.12)×10^-3 mm²/s vs (81.56±15.41)×10^-3 mm²/s} were also different between the SHCC group and the nodule group (all P<0.01). The detection rates of SHCC and DN on the background of cirrhosis by CT in combination with CUES or with MRI was 93.48% and 94.12%, respectively, which were significantly higher than those of by themselves alone (P<0.05).Conclusion The quantitative parameters of CT, CEUS and MRI can reflect tumor pathophysiology and hemodynamic changes to certain extents. However, single detection still has limitation to distinct SHCC and DN on the background of cirrhosis. The combinations of multiple imaging parameters improve the diagnostic accuracy and reliability.

Key words: Cirrhosis, Small hepatocellular carcinoma, Dysplastic nodule, Contrast-enhanced ultrasound, Magnetic resonance imaging, Quantitative parameter, Differential diagnosis