Qualitative And Quantitative Magnetic Resonance Imaging Assessment Of Focal Liver Lesions: A Study To Evaluate The Role Of Different MRI Sequences.

Background: Focal liver lesions have a broad differential diagnosis. MRI with its improved soft tissue characterization and newer sequences can significantly narrow the differentials especially when discriminating benign from malignant lesions. Methods: T1, T1 IN AND OUT OF PHASE, T2, LONG TE T2 AND Diffusion Weighted Imaging was done in 159 patients with USG documented focal liver lesion. Qualitative and quantitative assessment of ADC values and long TE images was done and a threshold for differentiating benign from malignant lesions was obtained. The MRI diagnosis was compared with final diagnosis obtained from histopathology in most cases or follow up and other tests (markers and RBC scan) were histopathology was not available. Sensitivity, specificity and accuracy of MRI sequences in differentiating various focal lesions were obtained. Results: T1 weighted images were useful for identifying fat, hemorrhage and iron within the lesions. T2 weighted imaging was able to correctly classify 82.0% lesions as malignant and 83.7% lesions as benign. Long TE T2 images were highly accurate in distinguishing haemangiomas and cysts from solid lesions. On diffusion-weighted (DW) imaging, 89.5% (i.e. 60 out of 67) lesions were correctly classified as malignant and 88.0% (i.e. 81 out of 92) lesions were correctly classified as benign. Threshold ADC value of 1.37 × 10-3 mm2/s is highly accurate for differentiating malignant from benign lesions. Conclusion: DWI is a sine qua non in liver lesion assessment allowing improved detection and characterization. Long TE T2 weighted imaging can accurately detect haemangiomas and cysts and rule out metastasis