Brainstem cavernoma surgery with the support of pre- and postoperative diffusion tensor imaging: initial experiences and clinical course of 23 patients

Abstract

The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows for the 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.Pre- and postoperative DTI visualization of corticospinal and sensory tracts were retrospectively analyzed in 23 individuals with BSC. Preoperative and postoperative DTI-fiber accuracy were associated to the neurological findings. Preoperatively, the corticospinal tracts were visualized in 90 % of the cases and the sensory tracts were visualized in 74 % of the cases. Postoperatively, the corticospinal tracts were visualized in 97 % of the cases and the sensory tracts could be visualized in 80 % of the cases. In all cases, the BSC had caused displacement, thinning, or interruption of the fiber tracts to various degrees. Tract visualization was associated with pre- and postoperative neurological findings. Postoperative damage of the corticospinal tracts was observed in two patients. On follow-up, the Patzold Rating (PR) improved in 19 out of 23 patients (83 %, p = 0.0002).This study confirms that DTI tractography allows accurate and detailed white matter tract visualization in the brainstem, even when an intraaxial lesion affects this structure. Furthermore, visualizing the tracts adjacent to the lesion adds to our understanding of the distorted intrinsic brainstem anatomy and it may assists in planning the surgical approach in specific cases.

Longitudinal evaluation of corticospinal tract in patients with resected brainstem cavernous malformations using high-definition fiber tractography and diffusion connectometry analysis: preliminary experience

“…DTI studies 11,12,28,31,37,40 in general have qualitatively demonstrated the orientation of the eloquent white matter tracts (deviated and partially interrupted) around the brainstem CMs for planning the surgical trajectory. A recent study 40 using DTI-based tractography retrospectively analyzed the pre-and postoperative visualization of the CST and sensory tracts in 23 cases.…”

“…A recent study 40 using DTI-based tractography retrospectively analyzed the pre-and postoperative visualization of the CST and sensory tracts in 23 cases. The improvement in visualization was associated with the patients' neurological status.…”

“…11,12,28,31,37,40 Its limitations include its inability to represent the crossing of multiple fibers or to determine with precision their cortical and subcortical terminations. 7,24 DTI indices (e.g., fractional anisotropy [FA]) are susceptible to partial volume effects, leading to underestimation in areas with multiple crossing fibers.…”

“…6,33 Despite these limitations, DTI has been an important adjunct in the resection of tumors 23,51 and CMs. 12,28,31,40 High-definition fiber tractography (HDFT), an advanced white matter imaging technique, addresses some of the limitations of DTI. HDFT is accurate in tracking fiber pathways through complex crossings to subcortical regions and targets.…”

Diffusion Tensor Tractography of the Brainstem Pyramidal Tract: A Study on the Optimal Reduction Factor in Parallel Imaging

“…DTT has proven effective for evaluating several brainstem pathologies (12)(13)(14)(15)18). A previous study (13) reported the reliability of DTT in differentiating between diffuse pontine glioma and brainstem demyelinating disease, in which the fiber tracts of the brainstem are displaced by a tumor but are obscured or even transected by demyelinating disease.…”