Quality assurance for intraoperative MRI RF coils in stereotactic neurosurgical planning

The application of MRI during a surgical procedure (intraoperative MRI) provides the surgical team with up-to-date anatomical information to improve precision and inform decision making during the operation. This requires the use of a stereotactic frame or RF coil that affixes to the patient throughout the procedure, with the clinical team requiring assurance that the image quality is consistent and appropriate. The following QA program has been developed in order to monitor the condition of an intraoperative head coil.

This was set up for a third party intraoperative 8-channel head coil in conjunction with a 3.0T MRI scanner. QA testing consists of acquiring a large Field of View isometric (1.5 mm) 3D T1-weighted rapid gradient echo (FFE) of a 5000 CC Phantom Bottle, with two dynamic acquisitions and the individual channel data saved. Offline analysis is then performed to calculate the signal-to-noise ratio (SNR) of the phantom within the coil, the SNR for each channel, and the distance (D) from the coil at which the SNR decreases to half the value within the coil.

Testing has been performed on a monthly basis since May 2022 with consistent values for SNR (including for each channel) and D. There were three occasions where the coil failed the QA tests.

A monthly QA program has been developed to monitor coil element performance, confirming that the coil has been functioning as expected.