gms | German Medical Science

Objective: With continuous improvement of surgical techniques and higher resolution in neuroimaging the management of lesions in the pons is constantly improving. Among pons structures with vital functions that are under the risk of being damaged by surgical manipulation, cranial nerve (CN) nuclei like CN V, VI, and VII play a critical role. The attempt to map the area of CN nuclei and to avoid unintended loss of their function could create an advantage for surgical outcome. We present our initial experiences of 7 patients analysed by DT-imaging in regard to locate and map CN nuclei in the pons and to possibly offer guidance for the surgical planning.

Method: DT-imaging obtained on a 3-T MRI in the area of CN nuclei V, VI and VII were retrospectively analyzed in 7 individuals with intraaxial lesions in the pons. Various levels of axial MR-images and color-coded maps were compared with corresponding anatomical sections of the pons from an anatomical atlas. FA and ADC-maps were generated for quantification of each CN area.

Results: The area of the CN nuclei was identified during the pre- and postoperative course. A list of anatomical structures in the pons could be identified and correlated with the clinical course of each patient. In most cases, associations between postoperative CN-symptoms and quantitative DTI values (FA and ADC) in the corresponding CN-area in the pons were demonstrated.

Conclusions: Our results suggest that DT-imaging allows quantification of certain areas of CN nuclei in pons lesions. When a lesion is present in these structures, mapping the area of cranial nerve nuclei with DT-imaging might help us to better understand the degree of anatomical involvement by the pathological process. In the future even higher spatial resolution DT-imaging could be potentially of importance when scheduling those cases for surgery.