NIMG-24. PATHOLOGY CONFIRMED RADIOGRAPHIC DIAGNOSIS OF TRUE PROGRESSION AND PSEUDO-PROGRESSION MADE BY ADVANCED BRAIN TUMOR IMAGING

Abstract

Differentiation of true tumor progression verse pseudo-pregresion in glioblastomas patients by routine MRI is a challenging task, in part because T1 enhancement and timeline similarities where pseudo-progression can happen within first 3-6 months post chemoradiation. We performed a retrospective data analysis of Advanced Brain Tumor Imaging (ABTI) protocol as a differentiating tool. 29 Patients, ages from 21 to 79 years old with18 Male and 11 females, were included in this study and their MRI showed evidence of new enhancement by RANO or McDonald criteria. ABTI protocol was performed 4 weeks later, including DSC and ASL perfusion, DTI, SWI, MRS and T1 WI delayed post contrast sequences with wash-in/wash-out maps (WIWOM). Eight patients underwent subsequent craniotomy and pathology reports are available for ABTI correlation. Patients were divided in three groups by pathology and ABTI results: a) 15 as pseudo-progression, featuring significant delay wash-in on WIWOM, low Cho/Cr, Naa and Cho, with/wo high lipids on MRS, low ASL/CBF and low DSC/r CBV. b) 9 patients as true progression, featuring significant areas of early wash-out on WIWOM, high Cho/Cr on MRS, high ASL/CBF on and DSC/r CBV. c) 6 cases as mixed responses displaying both pseudo-progression and true progression in separate areas. For patient with pseudo-progression group, original treatment was continued, with subsequent proven stability or lesion regression by MRI. Reports were rectified by pathology in 6 cases. Data analysis with pathological correlation indicates a high predictive value for the ABTI based pseudo-progression diagnosis, posing the proposed ABTI algorithm as a useful tool scrutinizing alleged conventional imaging based tumor progression diagnosis. Significant delay contrast wash-in, low Cho/Cr and low ASL/DSC perfusion parameters, are highly suggestive of treatment response/pseudo-progression, supporting ABTI routine utilization in the modern neurooncological practice to be further validated by a larger sample study.