CLIN-RADIOLOGY

Abstract

INTRODUCTION: Dynamic susceptibility contrast perfusion MRI (DSC MRI) has utility in differentiating recurrent malignant glioma from treatment-related changes. Preliminary studies suggest that arterial spin labeling (ASL) perfusion may be equal to DSC MRI for post-treatment tumor evaluation. We tested this hypothesis with a retrospective analysis of malignant gliomas for which ASL and/or DSC MRI were obtained. METHOD(S): Forty-five studies in 40 patients (18 female and 22 male; median age, 52) were re-evaluated by three neuroradiologists (each case was read by 2 neuroradiologists). Only malignant gliomas previously treated with chemoradiation were evaluated. Radiographic correlation was determined using a 3-point scale: 1 = increased perfusion/persistent tumor, 2 = equivocal perfusion/indefinite, and 3 = decreased perfusion/ treatment necrosis. Clinical assessment also used a 3-point scale: 1 = progressive disease, 2 = equivocal/disease progression versus treatment effect, and 3 = treatment effect or no evidence of disease progression. After independent scoring, the radiographic diagnosis was compared to the actual clinical diagnosis established at neuro-oncologic follow-up or by pathologic assessment. Observer concordance, technique concordance, and clinical accuracy were evaluated. RESULT(S): Observer concordance for ASL was complete in 28/45 cases and partial in 17/45 cases. For DSC MRI, observer concordance was complete in 17/28 cases and partial in 11/28 cases. ASL- and DSC MRI-based diagnoses were the same in 19/28 cases and discordant in 9/28 cases. In all but one of the 9 discordant cases, one of the two observers rated either the ASL or DSC MRI as indefinite. Nine patients had a treatment change at the time of imaging. Clinical assessment at follow-up confirmed the imaging assessment in 35/45 cases. Of the 10 discordant cases, 8 of the clinical assessments remained indeterminate for progression versus treatment effect, without change in therapy, at the time of follow-up. CONCLUSION(S): ASL perfusion may be a reliable alternative to DSC MRI for differentiating recurrent/persistent neoplasm from treatment effect. A controlled prospective study is warranted.