The Anatomical and Radiologic Relationship of the Superior Longitudinal Fasciculus/Arcuate Fasciculus with the Middle Cerebral Artery

Introduction: The superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) fiber pathway, which passes through the parietal region and connects the temporal and frontal lobes, has important functions. While this pathway has been extensively examined there is no study demonstrating its arterial supply and its 3D anatomical and radiologic relationship with the middle cerebral artery (MCA) and its branches. Our aim was to demonstrate the relationship of SLF/AF with the MCA by fiber dissection and radiologically.

Methods: Ten head specimens injected with colored silicone dye and fixed with 10% formalin were used. Hemispheres in 5 head specimens were removed from the cranium, vascular and meningeal tissues were cleaned and subjected to lateral to medial fiber dissection. In the other 5 head specimens, skin, subcutaneous tissue, bone, meninges and vessels above the supratentorial level were removed. Arteries were preserved along the lateral to medial fiber dissection. MR tractography and angiography images were taken in 10 healthy individuals and visualized in 3D.

Results: In the hemispheres with removed arterial structures, anatomical dissections were performed and SLF-C, SLF-II, SLF-III and AF fiber tracts were exposed and their figures were presented. In the other 5 head specimens with preserved arterial structures, the MCA was protected from the bifurcation to the medullary branches extending into these fibers and white matter dissection was performed, thus both SLF/AF fiber tract was shown and its 3D relationship with the MCA was presented as a whole. In MR tractography images of healthy individuals, the SLF-C, SLF-II, SLF-III and AF tracts were shown individually and together. The relationship between fiber tracts and vascular structure was presented in three dimensions by matching the tractography image with the 3D MCA angiography image obtained from MR angiography.

Conclusion : This is the first report to present the relationship of the MCA with the SLF/AF as a whole from the cortical branches to the medullary branches by anatomical dissection. The tractography of the SLF/AF and the angiography of the MCA were presented for the first time with 3D matching.