Comparison of 'dynamic susceptibility contrast' perfusion imaging and 'arterial spin labeling' imaging for grading of brain tumors

Perfusion MRI is an important advanced imaging technique in glial tumors since early diagnosis and correct grading increases survival rates. The purpose of this study is to assess the role of perfusion MRI (DSC-ASL) in grading brain tumors by comparing them to histopathology results. Thirty two patients were included in the study, 23 (71.9%) of which had high grade gliomas and 9 (28.1%) of which had low grade. ASL and DSC-rCBV images of all patients were evaluated visually by two neuroradiologists. Inter-observer agreement in DSC and ASL evaluation was found to be very good. In DSC images, relative cerebral blood volume (rCBV) of the lesions and in ASL relative signal intensity (rSI) was measured. In our study, visual evaluation of DSC and ASC maps were found to have low sensitivity and specificity for differentiation of low grade and high grade tumors. Measuring rCBV in DSC, however; was found to have high sensitivity. Therefore, we think these methods can provide information beyond conventional MRI for purposes of glial tumor grading, but should not be used alone for grading. ASL perfusion is likely to provide beneficial information in the future with technical advances and has the advantage of not requiring an exogeneous contrast agent.