Advanced diffusion-weighted imaging of invasive tumor front for identification of macrotrabecular-massive
Qianyun Liu1, Zhimin Yan2, Da Li1
1Department of Medical Imaging, Yueyang Central Hospital, No. 39 Dongmaoling Road, Yueyang, 414020, Hunan, China.
Objective:
To evaluate the performance of intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) in identifying the macrotrabecular-massive (MTM) subtype of hepatocellular carcinoma (HCC).
Materials And Methods:
This prospective study enrolled 76 consecutive patients who underwent surgical resection for HCC. Preoperative MRI examination, including multiple b value diffusion-weighted imaging (DWI), was performed. The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), kurtosis-corrected ADC (AD), and apparent diffusion kurtosis (AK) were calculated for the whole tumor (including central and peripheral parts) and within two peritumor 3-mm-thick layers (i.e., inner and outer layers). The presence of the MTM subtype was histopathologically assessed. Based on the quantitative imaging parameters between the two groups, logistic regression analysis was used to determine predictors of the MTM subtype, and receiver operating characteristics (ROC) curves were used to evaluate the diagnostic performance.
Results:
There were 58 MTM-negative tumors and 18 MTM-positive tumors. The ADC, D, and AD values for the whole tumor as well as the central and peripheral parts were significantly lower, while the D* value for the tumor peripheral part and D* value for the peritumor inner layer were higher in MTM-positive tumors compared to MTM-negative tumors (all P < 0.05). Multivariable analysis revealed that the AD value for the tumor peripheral part (odds ratio [OR], 0.498; P = 0.027) and the D* value for the peritumor inner layer (OR, 1.919; P = 0.038) were independent predictors of the MTM subtype. Incorporating these two parameters into a conventional model based on MRI features significantly improved diagnostic performance (area under the curve [AUC], 0.871 vs. 0.752; P = 0.020).
Conclusion:
Our proof-of-concept study demonstrates that advanced DWI-derived parameters of the invasive tumor front, located between the tumor core and liver parenchyma, provide incremental value over conventional MRI features for evaluating the MTM subtype of HCC.
