Apparent diffusion coefficient correlates with different histopathological features in several intrahepatic tumors

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Histopathological features of hepatic malignancies significantly influence patient prognosis and treatment strategies.
• Non-invasive imaging biomarkers are crucial for characterizing liver tumors and guiding clinical decisions.
• Apparent diffusion coefficient (ADC) derived from MRI shows potential in reflecting tumor microenvironment characteristics.

Purpose of the Study:

• To investigate the associations between ADC values and key histopathological features, including cell count, Ki 67 proliferation index, tumor-stroma ratio (TSR), and intratumoral lymphocytes.
• To evaluate the utility of ADC as a surrogate imaging marker across different types of primary and metastatic liver cancers.

Main Methods:

• A retrospective analysis of 149 patients with liver biopsies (hepatocellular cancer, intrahepatic cholangiocarcinoma, colorectal, breast, and pancreatic cancer metastases) was conducted.
• Mean ADC values were measured from pre-biopsy 1.5-T MRI scans.
• Spearman's rank correlation coefficients were calculated to assess associations between ADC and histopathological parameters (cell count, Ki 67, TSR, lymphocytes).

Main Results:

• Excellent inter-reader agreement was observed for ADC measurements.
• ADC significantly correlated with tumor cellularity in hepatocellular cancer (HCC), intrahepatic cholangiocarcinoma (iCC), and colorectal cancer (CRC) metastases.
• ADC reflected the tumor-stroma ratio (TSR) in breast cancer (BC) liver metastases and iCC, and Ki 67 in BC and CRC metastases.
• No significant correlations were found for pancreatic cancer (PC) metastases.

Conclusions:

• ADC serves as a valuable non-invasive imaging biomarker for assessing tumor cellularity and TSR in various hepatic malignancies.
• ADC measurements correlate with specific histopathological features in HCC, iCC, CRC, and BC liver metastases.
• ADC does not appear to reflect intratumoral lymphocyte counts in these lesions.