The three-dimensional protocol for imaging cerebrospinal fluid is new, and I developed it by adapting a protocol already available on the clinical 3 Tesla MRI used for this project, which is manufactured by Siemens Healthineers (Erlangen, Germany). Further research is necessary to explore similar adaptations on MR systems produced by other vendors. Besides offering the advantage of being readily available on a clinical MRI system, this protocol was advantageous because it could provide, for the first time, three-dimensional images of cerebrospinal fluid while inherently suppressing signal generated by the surrounding brain tissue, which may result in measurement inaccuracy caused by partial volume effects. Moreover, two versions of this protocol were developed: one high-resolution version (0.9-mm isotropic) to capture finer anatomical details of the brain structures containing cerebrospinal fluid; the other, with a lower resolution (3-mm isotropic), to trade some resolution accuracy for speed, and acquire images of dynamic changes in cerebrospinal fluid linked to 100% oxygen breathing. The processing pipeline developed to analyse these images was also novel, as it aimed to process images from a novel imaging protocol to obtain quantitative measurements of T1. This parameter was influenced by breathing pure oxygen.
Results related to T1 measurements showed that oxygen exchange between cerebrospinal fluid and brain tissue primarily occurs in two areas: the cortical subarachnoid space and the medial/posterior lateral ventricles. While these results aligned with findings from previous studies, this project was the first to evaluate changes across the whole brain owing to the use of a three-dimensional protocol. Further research is needed to assess the clinical relevance of these findings.
The results from this fellowship laid the foundations for characterising other structures containing cerebrospinal fluid, namely, perivascular spaces.
