Work

Nimg-80. Shape Attributes of Enhancing Lesion Boundaries Can Differentiate Tumor Recurrence From Pseudo-progression on Routine Brain Mri Scans: Preliminary Findings

Year: 2017

Type: conference-abstract

Abstract: A significant challenge in post-chemo-radiation response assessment in brain tumors is distinguishing pseudo-progression (PsP), a temporary radiation-induced treatment effect, from tumor recurrence (TR). PsP closely mimics TR appearance on MRI, making their visual identification challenging. This work targets analyzing enhancing lesion shape of TR and PsP. Studies show that tumors may alter white-matter structure due to infiltration leading to uneven lesion boundaries. The hypothesis is that shape analysis of lesion could reveal morphometric differences across PsP and TR, thus distinguishing them on MRI. 32 MRI studies were acquired from an IRB approved study from Brigham and Women’s hospital (10 PsP, 22 TR cases). Co-registration and bias correction followed by expert delineation of lesion were performed. Three shape features were computed; Curvedness (C), describes how highly curved a point is, Sharpness (S), measures sharpness of curvature, and Shape Index (SI), captures areas with low curvature, were computed from lesion regions for all subjects. The mean, standard deviation, median, and kurtosis were computed per feature. Finally, a KNN classifier and leave-one-out-approach were employed to identify the top 10 significant features between PsP and TR, to be used to classify cases from an independent study obtained from Cleveland Clinic (8 PsP, and 5 TR cases). The most significant features were identified as Mean of C (0.7 +/- 0.3 TR, 0.4 +/- 0.1 PsP), mean of S (1.5 +/- 1.6 TR, 0.6 +/- 0.4 PsP), and median of SI (0.4 +/- 0.1 TR, 0.06 +/- 0.6 PsP) of lesion, and resulted in correctly classifying 26 out of 32 subjects. These features, when used with subjects from the independent study, classified 10 out of 13 subjects. Shape features of enhancing lesion can classify PsP and TR on MRI. CLINICAL IMPLICATION: Distinction of PsP from TR helps early identify patients with TR, while avoiding overtreatment in PsP.

Source: Neuro-Oncology

DOI: 10.1093/neuonc/nox168.651