ESTRO 2024 - Abstract Book

S953

Clinical - CNS

ESTRO 2024

2899

Digital Poster

Can perfusion predict response to treatment in patients undergoing stereotactic radiosurgery?

Najmus S Iqbal 1,2 , Richard Wise 3 , Maeve Williams 4 , John N Staffurth 1,5 , James R Powell 1

1 Velindre University Hospital NHS Trust, Clinical Oncology, Cardiff, United Kingdom. 2 Cardiff University Brain Research Imaging Centre, Department of Psyhcology, Cardiff, United Kingdom. 3 G. D’Annunzio University, Institute for Advanced Biomedical Technologies & Department of Neuroscience, Imaging and Clinical Sciences, Chieti, Italy. 4 Velindre University Hospital NHS Trust, Medical Physics, Cardiff, United Kingdom. 5 Cardiff University, School of Medicine, Cardiff, United Kingdom

Purpose/Objective:

Stereotactic radiosurgery (SRS) is the treatment of choice for patients with brain metastases with a volume <20 cc, performance status 2 or better, and controlled or controllable extracranial disease (1). Surgery tends to be reserved for patients with larger volume single brain metastasis in a favourable location or where tissue is required to reach a diagnosis. The majority of brain metastases are diagnosed radiologically. NICE recommends performing standard structural Magnetic Resonance Imaging (MRI) sequences: T1-weighted pre and post contrast volume, T2- weighted, fluid-attenuated inversion recovery (FLAIR) and diffusion weighted imaging (DWI) (1). Perfusion MRI is not performed as a standard, although it is used frequently to differentiate between true and pseudo-progression (5). Choosing the most appropriate treatment to optimise clinical outcomes can be challenging and limited information exists from standard imaging that can predict response to treatment. In this study we explored whether tumour perfusion could be used to predict response to treatment in patients with brain metastases. We performed a study in patients with brain metastases receiving SRS treatment whereby patients underwent arterial spin labelling (ASL) MRI scans prior to, and at 1- and 3-months after SRS treatment, to measure changes in tumour perfusion, utilising the 3T Siemens MRI scanner at the Cardiff University Brain Research Imaging Centre (CUBRIC). We used ASL MRI to measure cerebral blood flow (CBF) in 20 patients between April 2017 and December 2018. To normalise for age, CBF in brain metastasis was calculated as a ratio to CBF in grey matter (BM:GM ratio). Mann-Whitney U Test was performed to test the statistical significance. A statistical significance of a p-value <0.05 was used. 20 patients had MRI imaging at baseline, 15 at 1 month and 8 at 3 months including T1 and T2 weighted images along with 3D pulsed ASL sequences. MRI data of 26 metastases in 20 patients who had MRI scans at CUBRIC were analysed. Response assessment in Neuro-Oncology in brain metastases (RANO-BM) criteria was used to assess tumour status (2). In addition to these scans at CUBRIC, patients underwent routine clinical assessment MRI scans at 3 months following SRS. Material/Methods:

Results: