Magnetic resonance imaging-based classification of trigeminal nerve-superior cerebellar artery relationships

Figure 1 Workflow for identifying the trigeminal nerve and its relationship with the superior cerebellar artery. Step 1: Identification of the trigeminal nerve root on axial slices; Step 2: Confirmation on sagittal and coronal planes; Step 3: Measurement of superior cerebellar artery-trigeminal nerve distance on coronal reconstruction. TN: Trigeminal nerve; SCA: Superior cerebellar artery.

Figure 2 Magnetic resonance imaging-based classification of superior cerebellar artery-trigeminal nerve 8 anatomical types. A-H: Magnetic resonance imaging-based classification of the eight anatomical relationship types between the superior cerebellar artery and the trigeminal nerve: Superior (A), superolateral (B), superomedial (C), medial (D), inferomedial (E), inferior (F), inferolateral (G), and lateral (H). TN: Trigeminal nerve; SCA: Superior cerebellar artery.

Figure 3 Distribution of the superior cerebellar artery-trigeminal nerve distance by demographic factors. A: Boxplot comparing left vs right sides; B: Boxplot comparing female and male patients; C: Scatterplot with regression line comparing superior cerebellar artery-trigeminal nerve distance across age. SCA-TN: Superior cerebellar artery-trigeminal nerve.

Figure 4 Distance and contact frequency according to the superior cerebellar artery-trigeminal nerve superior cerebellar artery-trigeminal nerve relationship. A: Boxplot of superior cerebellar artery-trigeminal nerve distances for each anatomical relationship; B: Heatmap illustrating frequency of superior cerebellar artery-trigeminal nerve contact by relationship type (green = no contact, orange = contact). SCA-TN: Superior cerebellar artery-trigeminal nerve.

Figure 5 Examples of neurovascular contact between the superior cerebellar artery and the trigeminal nerve in different anatomical configurations. A: Medial type; B: Inferolateral type; C: Inferior type. TN: Trigeminal nerve; SCA: Superior cerebellar artery.

Figure 6 Variability in the origin of the superior cerebellar artery. A: Bilateral origin from the basilar artery; B: Common origin with the posterior cerebral artery; C: Unilateral origin from the posterior cerebral artery; D: Boxplot comparing superior cerebellar artery-trigeminal nerve distance according to origin. BA: Basilar artery; PCA: Posterior cerebral artery; SCA: Superior cerebellar artery.

Figure 7 Proposed magnetic resonance imaging-based classification system of the superior cerebellar artery-trigeminal nerve relationship, represented as a heatmap of frequency distribution for each anatomical type. TN: Trigeminal nerve; SCA: Superior cerebellar artery.