CHARACTERIZATION OF HEPATIC METASTATIC LESIONS USING MAGNETIC RESONANCE IMAGING

Abstract

Background. The liver is the most common organ to be involved with metastatic disease. So early detection and characterization of liver lesions in a patient of known primary is of utmost importance.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of various MRI sequences including gadobenate-enhanced MRI in the detection and characterization of liver lesions in a patient of known primary malignancy and to compare MRI with Contrast-enhanced Computed Tomography (CECT) and Ultrasonography (USG) in the detection of liver lesions.

STUDY DESIGN: Prospective study.

PARTICIPANTS: Patients of known primary malignancy with USG/ CECT documented indeterminate liver lesions.

METHODS: All patients underwent multiphase MRI. The final diagnosis was established by HPE/FNAC.

RESULTS. A total of 43 patients of known primary malignancy were enrolled. MRI gave a provisional diagnosis of liver metastases in 21 patients and benign disease in 22 patients with histopathological correlation revealing two false negative and one false positive result. In the detection of lesions, Diffusion-weighted imaging (DWI) outscored other sequences (92.9% vs 83.5% in hepatobiliary phase vs 55.0% in T2-weighted sequences) with a statistical significant difference noted only in comparison with T2-weighted sequences (p<0.001) . In 16 patients MRI added new lesions that were not detected by CECT/USG. Sensitivity and specificity of MRI was 90.9%/ 95.2% and 97.9% and 96.8% for per-patient and per-lesion basis respectively.

CONCLUSION: Multiphase MRI improves both detection and characterization of liver metastases. Adding DWI to the routine MR sequences helps in detecting small liver metastases (<10mm) not detected by conventional T2-weighted sequences.

IMPLICATIONS: Multiphase MRI is a useful diagnostic tool that has the potential to replace other modalities in detecting liver metastases.