Retrieving fMRI data in real-time: difficulties and pitfalls

Abstract

One of the significant challenges in real-time fMRI environments is to ensure that the functional images are exported in real-time. The prerequired ability to reconstruct these images immediately after the acquisition has already been resolved in 2004. Nowadays, more sophisticated sequences allow for higher resolution and faster repetition times and thereby challenging the ability to export this data in real-time. In this article, we tackle the potentially arising problem of sending the reconstructed data from the MRI to an external PC to perform the real-time fMRI analysis. We show that depending on the implementation of the data transfer, long delays can occur that can differ drastically in time and how often they occur. In addition, we propose a solution for SIEMENS MRI devices which was tested and applied already on multiple MRI devices including 3T and 7T machines on different vendor software versions. This new technique can be used as a blueprint that can be directly applied to other manufacturers. We also provide the source code of the described solution and show that the delay in the data transfer can be completely resolved using our proposed procedure. Finally, we integrate measurement options for the data transfer times to improve quality measures in real-time fMRI environments (e.g., clinical) that can implement the proposed solution. Efforts should be taken by the real-time community and MRI manufacturers to employ a standardized real-time export e.g., similar to the lab streaming layer which is used as a standard export method in EEG environments.

Practical challenges of continuous real‐time functional magnetic resonance imaging neurofeedback with multiband accelerated echo‐planar imaging and short repetition times

“…This, and helpful advice from Siemens engineers and reviewers helped narrow down the problem: The console platforms of both Prisma Fit scanners are equipped with a Windows 7‐based operating system only supporting an older version (2.x) of the Server Message Block (SMB) protocol required to exchange data with the real‐time processing laptop. Older SMB versions are slower and incur more overhead than newer protocol versions (e.g., SMB 3.3, see also Lührs et al, 2022 ). Especially when using outdated devices (e.g., Windows XP‐based computers supporting only SMB versions 1.x), this could lead to such massive delays that even neurofeedback experiments with intermittent feedback may be affected.…”