Analysis and 3-dimensional visualization of neurovascular compression syndromes.

RATIONALE AND
OBJECTIVES: Neurovascular compression syndromes are currently examined with 2-dimensional representations of tomographic volumes. To overcome this drawback, coarse segmentation followed by direct volume rendering of magnetic resonance (MR) data is introduced supporting a detailed 3-dimensional analysis of the related structures.
MATERIALS AND METHODS: This approach is based on MR-CISS (constructive interference in steady state) volumes providing the required high resolution to achieve an improved spatial understanding. In relation to the size of the involved nerves and vessels, an explicit segmentation is extremely difficult. Therefore, a semi-automatic preprocessing sequence was developed consisting of noise reduction, morphologic filtering, and volume growing. To delineate the target structures within the segmented and labeled subvolumes, interactive direct volume rendering was applied that allows delineating the target structures in the area of the cerebrospinal fluid with implicit segmentation based on predefined transfer functions assigning opacity and color values to the intensity values of the image data. For a further improved analysis, registration of the MR-CISS volumes with MR angiography is recommended to support differentiating vessels and nerves on the one side and arteries and veins on the other.
RESULTS: The presented method was applied in a consecutive series of 47 cases of different neurovascular compression syndromes, supporting the presurgical analysis of the image data. Additionally, the results were compared with the operative findings.
CONCLUSION: Overall, this approach contributes significantly to an optimized 3-dimensional analysis and understanding of neurovascular compression syndromes. Based on the obtained results, it is of high value for the planning of surgery.