Differentiation of common liver tumors using tumor-to-liver contrast on routine non-contrast T2-weighted magnetic resonance imaging.

INTRODUCTION Accurate classification of liver tumors requires contrast-enhanced MRI. However, contrast agents are contraindicated in patients with renal impairment or allergies. Concerns regarding the environmental impact of gadolinium-based agents have increased. Thus, classification using non-contrast MRI is desirable. This study evaluated whether tumor-to-liver contrast (TLC) derived from T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), along with apparent diffusion coefficient (ADC), can differentiate common liver tumors: hepatocellular carcinomas (HCCs), metastases, and hemangiomas.

Methods

We retrospectively analyzed 119 patients with 122 liver tumors undergoing liver MRI. We calculated TLC from T2WI and DWI (b = 1000 s/mm²), and measured ADC values. Tumors were classified as HCCs, metastases, or hemangiomas based on radiological or pathological findings. Analyses were stratified by liver function using the albumin-bilirubin (ALBI) score. Group differences were assessed using the Kruskal-Wallis and Steel-Dwass tests. Diagnostic performance was evaluated using one-versus-rest receiver operating characteristic (ROC) analysis.

Results

T2WI-derived TLC differed significantly among tumor types (p < 0.05) and was highest in hemangiomas, followed by metastases and HCCs. DWI-derived TLC and ADC values differed in some tumor comparisons but showed greater variability and overlap. These patterns persisted after ALBI stratification. ROC analysis showed that T2WI-derived TLC performed well for hemangiomas (AUC = 0.975) and HCC (AUC = 0.839), whereas ADC performed best for metastases (AUC = 0.716). Overall, T2WI-derived TLC outperformed DWI-derived TLC.

Conclusions

TLC derived from non-contrast T2WI may serve as a practical, observer-independent marker for differentiating liver tumors, particularly in patients who cannot receive contrast agents. PLAIN LANGUAGE SUMMARY MRI scans with contrast agents are often used to identify different types of liver tumors, but some people cannot safely receive these agents. This study reviewed MRI scans from people with liver tumors and examined whether measurements from standard non-contrast MRI images could help distinguish between common tumor types. This study found that a measurement taken from T2-weighted MRI images was particularly effective at differentiating liver tumors, especially hemangiomas and hepatocellular carcinoma, without the need for contrast agents. This matters because non-contrast MRI methods may help support diagnosis in people who cannot receive contrast agents and may reduce reliance on these substances.