DOI: 10.36347/sjams.2016.v04i06.049

Pages: 2111-2119

The major aim of the present study was to measure the ADC values of low grade and high grade tumors using diffusion weighted MRI, to determine their contribution to differential diagnosis and also to propose a cut off ADC value. A retrospective study was done in which the magnetic resonance imaging findings of 50 patients diagnosed as having intra-axial brain tumors on histopathology were studied co-relate the ADC values with the World Health Organization grade of the tumor. Higher grade tumors had lower ADC values (<1.0 x 10-3 mm2/s) than lower grade tumors (>1.0 x 10-3 mm2/s). Conventional MR was 100% accurate in differentiating grade I from higher grade tumors. Cut-off ADC of >1.4 X10-3 mm2/s was 100% specific for grade I tumors though differentiation among the various grade I tumors was not possible on DWI. Using a cut-off ADC value of 1.0 X10-3 mm2/s, the sensitivity of MRI to differentiate low grade from high grade tumors was increased from 91% to 100%, specificity from 84.6 to 96% and accuracy from 86.4 to 97.3%. Diffusion weighted imaging and the accompanying ADC values can add useful information to the morphological details provided by contrast enhanced magnetic resonance imaging.. It can increase the PPV, NPV and accuracy of MRI to distinguish low grade from high grade neoplasm's as well as to differentiate lymphomas from other malignant lesions.