A standardized protocol for detection of Amyloid Related Imaging Abnormality (ARIA) on 3T Philips Magnetic Resonance Imaging (MRI)

Abstract Background ARIA is a common side effect of aducanumab, the first anti‐amyloid pharmacotherapy approved by the US Food and Drug Administration (FDA) to treat Alzheimer’s disease. Regular MRI is required by FDA to detect and monitor different forms of ARIA during initiation of therapy. MRI protocols must be a) high resolution to detect abnormalities with high sensitivity, b) fast to accommodate workflow and ensure patient compliance and c) standardized to maximize data acquisition consistency across sites. Based on a vendor agnostic protocol recommendation by Benzinger et al (CTAD 2021), we propose specific parameters for 3T Philips systems, for an accelerated and enhanced protocol. Method The protocol was developed on a 3T Philips Elition X scanner, using 32‐channel head coil, and included 3D T1, 3D FLAIR, 2D DWI, 2D T2 * and multi echo 3D Susceptibility Weighted Imaging (SWI) sequences. Result Acquisition voxel resolution of 3D T1, 3D FLAIR, T2 * and DWI matches current recommendations. 3D SWI resolution is 0.7x0.7x2mm. Compressed‐SENSE (C‐SENSE) acceleration is applied on 3D T1, 3D FLAIR, T2 * and 3D SWI. SENSE is applied on DWI (Figure 1). Total acquisition time including the additional 3D SWI scan is 11 minutes, 6 minutes faster than the original recommendation. Qualitative assessment of images showed high signal‐to‐noise and contrast‐to‐noise. Images were free of acceleration related artifacts. Automated slice prescription localizer ensures better reproducibility for longitudinal assessment. Conclusion Imaging protocol standardization is necessary to ensure consistent accuracy for diagnosing ARIA. Broad recommendations leave room for variability, therefore specific parameters are needed to achieve cross‐platform standardization. Our protocol is applicable for 3T Philips systems with compressed‐SENSE capability and 32‐channel head coil. The recommended C‐SENSE values maintain image quality with shorter exam time. This is more comfortable for patients and easier to fit into the workflow. The higher sensitivity of SWI can improve thresholds for therapy monitoring and provide additional quantitative measurements.