Magnetic Resonance Diffusion-Weighted and Perfusion-Weighted Imaging in Differentiation of Brain Lesions

Abstract

Introduction: In an educational manner are shown the diagnostic benefits of DWI and PWI in some clinically relevant cases. Aim: DWI estimates the lesion structure, water content, cellularity. PWI shows the capillary density, neovascularization. Significant differences in diffusion and perfusion were found in cases of acute ischaemia, postencephalitic lesion, metastatic lesion, lymphoma, low-and high-grade glioma. Material and Methods: DWI and PWI DSC (dynamic susceptibility contrast) Spin Echo EPI, and T1 pre, T2, T2 FLAIR, 3DT1 postcontrast images. Injector MEDRAD, Gadovist 1,0 mmol/l, dose 0,1ml/kg. Physiological serum 20 ml. Injection speed 5ml/sec. The minimum ADC (apparent diffusion coefficient) and the maximum rCBV(relative cerebral blood volume) value of each lesion was determined by placing ROI(region of interest) with area between 50-60 mm2, using the Advantage Workstation (GE Healthcare) by the radiologist. Calculation of rCBV and rADC, takes into account the maximum values in the lesion area, compared with the intact contralateral parenchymal zone. Results: Significant differences were found in these cases as follows: acute ischaemia ADC=0,0003 mm/s2, rADC=0,395, rCBV=0,113; meta ADC=0,00061 mm/s2, rADC=1,19, rCBV=0,7; lymphoma ADC=0,00071 mm/s2, rADC=1,5, rCBV=0,384; postencephalitic lesion ADC=0,00064 mm/s2, rADC=1,13, rCBV=0,44; low-grade glioma ADC=0,00184mm/s2, rADC=2,5, rCBV=0,5; high-grade glioma ADC=0,00064 mm/s2, rADC=0,816, rCBV=4. Conclusion: DWI and PWI are helpful in glioma grading, in differentiation of acute ischemia from glial tumor, in discriminating between high-grade glioma and lymphoma. This could help in finding the right and earlier treatment for the patients.