Brainstem Cavernoma Surgery with the Support of Pre- and Postoperative Diffusion Tensor Imaging

Objective: The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows visualization of white matter tracts and enables a better understanding of the anatomical location of corticospinal and sensory tracts before and after surgery. We investigated the feasibility and clinical usefulness of DTI based fiber tractography in patients with BSC. We assessed the accuracy of fiber visualization, its correlation with clinical outcome, and its value for planning the surgical approach.

Methods: Pre- and postoperative DTI visualization of corticospinal and sensory tracts were retrospectively analyzed in 23 individuals with BSC. Pre- and postoperative DTI-fiber accuracy was correlated with neurological findings.

Results: Preoperatively, DTI was available in 21 out of 23 patients. Corticospinal tracts were visualized in 90% of the cases. The sensory tracts could be visualized in 82% of the cases. Postoperatively, DTI was available in 15 out of 23 cases. The corticospinal tracts were visualized in 93% of the cases. Sensory tracts could be visualized in 79% of the cases. In each case the BSC has caused displacement, thinning, or interruption of the fiber tracts to various degrees. Tract visualization correlated well with the pre- and postoperative neurological findings. There was no surgical damage of corticospinal tracts detectable on postoperative DTI. In one patient the sensory tracts were lost postoperatively.

Conclusions: This study confirms that DTI tractography allows accurate and detailed white matter tract visualization not only in the supratentorial area but also in the brainstem, even when this structure is affected by an intra-axial lesion. There is a clear correlation between the appearance of the tracts and the patients’ neurological status. Furthermore, visualizing the tracts adjacent to the lesion adds to our understanding of the distorted intrinsic brainstem anatomy and furnishes valuable information for planning the surgical approach.