Peritumoral edema measurements provide additional information to RANO-BM based assessment of lung cancer brain metastases after Gamma Knife therapy
Manpreet Kaur1, Gabriel Cassinelli1, Marc von Reppert1, Leon Jekel1, Sunitha Varghese1, Irene Dixe1, Antonio Omuro1, Veronica Chiang1, Mariam Aboian1
1Yale School of Medicine
Objective:

In our study, we aimed to better understand the correlation between post-GK peritumoral edema and CE lesion. 

 

Background:
Gamma Knife (GK) has become standard of care to treat brain metastases (BM), however there is little understanding of the posttreatment volumetric changes of peritumoral edema of BM due to paucity of tools for volumetric segmentation in neuroradiology clinical practice. Recently PACS-integrated tools have become available in select clinical practices, facilitating the comparison of volumetric treatment response curves of peritumoral edema to response curves of RANO-BM based measurements of the contrast-enhancing (CE) tumor core.
Design/Methods:

Patients with NSCLC BM ≥10 mm on post-contrast T1-weighted image and treated with GK had volumetric measurements for up to seven follow-ups using a PACS-integrated tool that segments the FLAIR hyperintense volume surrounding the CE lesion. The 2D and volumetric measurements were compared by creating response curves with incorporation of clinical information including steroid timing.

Results:

Fifty NSCLC BM were included with a median pretreatment metastasis volume of 8.5 cm3 (IQR 1–47 cm3, n=36). A significant decrease was measured at 0–90 days post-GK (median 1.2 cm3, IQR 0.5–6.1 cm3, n=31). The time of peak median peritumoral volume increase was at >365 days (median 1.4 cm3, IQR 0.4–8.1 cm3, n=19). There was a positive correlation between longest diameter (LD) and peritumoral edema volume (rs=.75, p<.05). At 181–270 days post-GK 50% of BM showed incongruent response course for LD and peritumoral edema volume. The congruence/incongruence ratio of edema to enhancing portion of BM changed over follow-up time.

Conclusions:

Volumetric edema assessment of BM post-GK provides critical additional information as compared to RANO-BM based response curves.

10.1212/WNL.0000000000203091