Background: Diffusion weighted Imaging (DWI) is a useful noninvasive tool in MRI as it can be performed quickly and does not require contrast injection. In addition to it, DWI imaging and apparent diffusion coefficient (ADC) quantification not only can add additional anatomical data about the lesion but can also help in characterization of focal liver lesions into malignant or benign. The study attempts to establish a cut off value of ADC differentiating a benign from malignant lesion. Materials and Methods : 32 patients with age group of 40-85 years with 46 diagnosed focal liver lesions on CT and MRI were included in the study. MRI was performed using 1.5 Tesla GE Healthcare HDxT machine. Conventional sequences followed by diffusion weighted sequences were acquired. Quantitative analysis was derived from ADC maps with calculation of ADC values. ADC values of the hepatic lesions were compared with histopathology as reference standard and analyzed statistically. Results: In this study, 25 focal lesions in 18 patients had histopathological diagnosis of malignant pathology and had mean ADC value 1.13(x10 (−3) mm 2 /s) and 21 lesions in 14 patients with histopathological diagnosis of benign pathology had ADC value of 1.63(x10 (−3) mm 2 /s). Statistically significant difference between ADC value of benign and malignant lesions was found. Conclusion: The study proclaimed that DWI with ADC quantification be used as an additional non invasive MRI tool to differentiate benign and malignant hepatic lesions with a sensitivity of 85.7%, specificity of 88%, PPV of 88% and NPV of 85.7%

Objectives:To assess the utility of dynamic imaging namely, wash-in and wash-out characteristics through multidetector contrast-enhanced computed tomography in differentiating benign and malignant pulmonary masses.Materials and Methods:Seventy-three patients who were suspected to have malignant pulmonary mass on the basis of clinical symptoms and chest radiograph were included in the study. All the patients underwent multidetector computed tomography scanning, and three series of images were obtained for each patient-noncontrast, early enhanced, and 15 min delayed enhanced scans. Computed tomography (CT) findings were assessed in terms of washin, absolute, and relative percentage washout of contrast. Biopsy of the mass was done and sent for histopathological evaluation. Sensitivity, specificity, and area under curve for diagnosing malignancy in the lung masses were calculated by considering both the wash-in and wash-out characteristics at dynamic CT and plotting the receiver operating curve after the final diagnosis which was obtained by histopathological evaluation.Results:Threshold net enhancement (washin) value of >22.5 HU had sensitivity, specificity, and diagnostic accuracy of 88.5%, 57.1%, and 82%, respectively, in predicting malignancy. Threshold relative percentage washout of <16.235% had 98.1%, 85.7%, and 94% sensitivity, specificity, and diagnostic accuracy, respectively, and threshold absolute percentage washout of <42.72% had 98.1%, 95.2%, and 95% sensitivity, specificity, and diagnostic accuracy, respectively, in predicting malignancy.Conclusion:Threshold net enhancement (washin), absolute and relative washout percentages can be used to predict malignancy with very high diagnostic yield, and possibly obviate the need of invasive procedures for diagnosis of bronchogenic carcinoma.