Background: Amide proton transfer-weighted (APTw) imaging provides molecular-level information for comprehensive tumor characterization, aiding in diagnosis, grading, and treatment response monitoring. The study aimed to investigate the potential of APT imaging in simultaneously predicting three key markers of hepatocellular carcinoma (HCC) aggressiveness-microvascular invasion (MVI), Ki-67 labeling index (LI) and histologic grade-and compare its performance to that of diffusion-weighted imaging (DWI).
Methods: Fifty-six patients with histologically confirmed HCC underwent abdominal magnetic resonance imaging (MRI) including APTw and DWI. Tumor mean APTw and apparent diffusion coefficient (ADC) values were measured and correlated with Ki-67 LI. The differences of APTw and ADC values between MVI positive (MVI+) and negative (MVI-), high and low Ki-67 LI, and high- and low-grade HCC were analyzed. The diagnostic efficacy of APTw and ADC for predicting HCC aggressiveness was assessed using receiver operating characteristic (ROC) curve analysis.
Results: APTw positively correlated with Ki-67 LI (ρ=0.49, P<0.001) and ADC negatively correlated with Ki-67 LI (ρ=-0.27, P=0.04). HCC with MVI+ had higher APTw values than MVI- (1.68%±1.02% vs. 0.21%±1.29%; P<0.001). High Ki-67 LI had higher APTw median values than low Ki-67 LI (1.57% vs. 0.16%; P<0.001). High-grade HCC had higher APTw values than low-grade (1.54%±1.10% vs. 0.02%±1.25%; P<0.001). Diagnostic performance of APTw for predicting MVI+, high Ki-67 LI, and high-grade HCC, was promising with area under the curve values of 0.82 (ADC: 0.65), 0.85 (ADC: 0.76), and 0.82 (ADC: not applicable), respectively.
Conclusions: APTw imaging could potentially provide additional value in assessing HCC aggressiveness, complementing the information obtained from DWI.
Keywords: Hepatocellular carcinoma (HCC); amide proton transfer; diffusion-weighted imaging (DWI); microvascular invasion (MVI).
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