Article Figures & Data
Figures
- Fig 1.
Grades 0 and 1 neurovascular conflict. Coronal NE-CISS (A) and CE-CISS (B) images show grade 1 (simple contact) on the patient's right side with a branch from the superior cerebellar artery (white solid arrow) contacting the cisternal segment of the trigeminal nerve root (dashed black arrow) from above. Note enhancement of the artery on the CE-CISS image. On the patient's left, the cisternal trigeminal nerve root (dashed black arrow) has no neurovascular conflict (grade 0).
- Fig 2.
Grade 2 neurovascular conflict. Coronal NE-CISS (A) and CE-CISS (B) and sagittal NE-CISS (C) and CE-CISS (D) images show neurovascular conflict of the cisternal segment of the patient's right trigeminal nerve with a branch of the superior cerebellar artery from above (solid white arrow) and the superior petrosal vein from below (dashed white arrow), resulting in flattening of the nerve near the porus trigeminus. On the NE-CISS images (A and C), the nerve is not well-delineated from the adjacent vascular structures. On the CE-CISS images (B and D), the vessels enhance, outlining the compressed nerve between them. Zoomed-in images of the site of neurovascular conflict in the coronal plane (E and F) illustrate the poor contrast between vessels and nerve on the NE-CISS image (E) and the improved contrast after administration of gadolinium contrast material (F), allowing more confident delineation of the compressed nerve from the adjacent vessels (G). Both NE-CISS and CE-CISS images were interpreted as grade 2 compression. On the patient's left, grade 0 was given for both the NE-CISS and CE-CISS images.
- Fig 3.
Grade 3 neurovascular conflict. Coronal NE-CISS (A) and CE-CISS (B) images show compression of the cisternal segment of the patient's right trigeminal nerve (black dashed arrow) by branches of the superior cerebellar artery from above (solid white arrow). On the unenhanced image (A), the nerve root is not well-distinguished from the compressing arterial branches. After contrast administration (B), at least 2 arterial branches enhance, allowing more confident delineation of the markedly compressed nerve. Zoomed-in images of the site of neurovascular conflict in the coronal plane (C–E) illustrate the poor contrast between vessels and nerve on the NE-CISS image (C) and the improved contrast after administration of gadolinium contrast material (D), allowing more confident delineation of the compressed nerve from the adjacent vessels (E). In this patient, grade 3 was given for both the NE-CISS and CE-CISS images, but the measured CSA was lower and the degree of flattening was more pronounced on the CE-CISS images. On the patient's left, grade 0 was given for both the NE-CISS and CE-CISS images.
- Fig 4.
High-grade neurovascular conflict. Coronal NE-CISS (A) and CE-CISS (B) images show compression of the distal cisternal segment of the patient's left trigeminal nerve (gray dashed arrow) by a branch of the superior petrosal venous complex from below (solid white arrow). On the unenhanced image (A), the nerve root is not well-distinguished from the compressing venous branch. After contrast administration (B), the venous branch fills with contrast, showing a severely compressed unenhanced adjacent trigeminal nerve root at the level of the porus trigeminus. Zoomed-in images of the site of neurovascular conflict in the coronal plane (C–E) illustrate the poor contrast between vessels and nerve on the NE-CISS image (C) and the improved contrast after administration of gadolinium contrast material (D), allowing more confident delineation of the compressed nerve from the adjacent vessel (E). In this patient, grade 2 was given on the NE-CISS and grade 3 was given on CE-CISS images. On the patient's right, grade 1 was given on both the NE-CISS and CE-CISS images.
- Fig 5.
Correlation of the metrics of neurovascular conflict with postsurgical outcomes after MVD. Grades of neurovascular conflict (A), CSA (B), and DOF (C) were correlated with different postsurgical outcomes after MVD, as described in the individual graphs. Non-con indicates non-contrast; Con, contrast-enhanced.
- Fig 6.
Receiver operating curves assessing the performance of the grade of neurovascular conflict (A, D, and G), CSA (B, E, and H), and DOF (C, F, and I) in predicting complete relief without further need for analgesic medication (type 1 outcome) after MVD (A–C), complete relief with or without further need for analgesic medication (type 1 or 2 outcome) after MVD (D–F), and symptom side in patients with TN (G–I) for both NE-CISS and CE-CISS images, as delineated in the graphs. The area under the curve and P values comparing the NE-CISS and CE-CISS curves are provided in the individual graphs.
Tables
- Table 1:
Prevalence of various grades of neurovascular conflict and types of vascular involvement in patients with TN and in controls
Contrast Enhancement Symptomatic Side (No.) (%) of 81 Cases Asymptomatic Side (No.) (%) of 81 Cases Control (No.) (%) of 30 Cases Grades of neurovascular conflict 0 Contrast− 10 (12.3) 27 (33.3) 12 (40.0) Contrast+ 10 (12.3) 27 (33.3) 12 (40.0) 1 Contrast− 33 (40.7) 48 (59.3) 18 (60.0) Contrast+ 29 (35.8) 48 (59.3) 18 (60.0) 2 Contrast− 26 (32.1) 6 (7.4) 0 (0.0) Contrast+ 15 (18.5) 6 (7.4) 0 (0.0) 3 Contrast− 12 (14.8) 0 (0) 0 (0.0) Contrast+ 27 (33.3) 0 (0) 0 (0.0) 1, 2, or 3 Contrast− 71 (87.7) 54 (66.7) 18 (60.0) Contrast+ 71 (87.7) 54 (66.7) 18 (60.0) 2 and 3 Contrast− 38 (46.9) 6 (7.4) 0 (0.0) Contrast+ 42 (51.9) 6 (7.4) 0 (0.0) Artery alone 27 (33.3) 17 (21.0) 4 (13.3) Artery involved 49 (60.5) 30 (37.0) 5 (16.7) Vein alone 22 (27.2) 24 (29.6) 12 (40.0) Vein involved 44 (54.3) 37 (45.7) 13 (43.3) Mixed 22 (27.2) 13 (16.0) 1 (3.3) Note:—Contrast+ indicates contrast enhancement; Contrast−, no contrast enhancement.
Grades of Neurovascular Conflict Contrast Enhancement P Values Contrast vs Noncontrast Sensitivity Specificity Sym vs Asym Sym vs Cntrl Asym vs Cntrl Sym Asym 0 Contrast− .002 .002 .51 1 1 12.3% 66.7% Contrast+ .002 .003 .51 12.3% 66.7% 1 Contrast− .03 .09 1 0.63 1 40.7% 40.5% Contrast+ .004 .03 1 35.8% 40.5% 2 Contrast− <.001 <.001 .19 0.07 1 32.1% 94.6% Contrast+ .06 .01 .19 18.5% 94.6% 3 Contrast− <.001 .03 1 0.001 1 14.8% 100.0% Contrast+ <.001 <.001 1 33.3% 100.0% 1, 2, or 3 Contrast− .002 .003 .51 1 1 87.7% 35.1% Contrast+ .002 .002 .51 87.7% 35.1% 2 and 3 Contrast− <.001 <.001 .19 0.64 1 46.9% 94.6% Contrast+ <.001 <.001 .19 51.9% 94.6% Note:—Sym indicates symptomatic; Asym, asymptomatic; Cntrl, control; Contrast +, contrast enhancement; Contrast −, no contrast enhancement.
Involvement of Neurovascular Conflict P Values Sym vs Asym Sym vs Cntrl Asym vs Cntrl Contrast vs Noncontrast Artery alone 0.11 0.06 0.43 33.3% 81.1% Artery involved .005 <.001 .06 60.5% 68.5% Vein alone 0.86 0.25 0.36 27.2% 67.6% Vein involved 0.35 0.39 1 54.3% 55.0% Mixed 0.13 0.007 0.11 27.2% 87.4% - Table 4:
Cutoff values for grade of neurovascular conflict, CSA, and DOF to obtain the highest sum of sensitivity and specificity in predicting complete relief of pain after MVD (type 1 outcome), complete relief of pain with or without need for analgesic medication (type 1 or 2 outcome), or in predicting the side of symptoms in patients with TN
Outcome Cutoff Contrast Sensitivity Specificity Type 1 Grade ≥2 − 59.6 90.7 ≥2 + 67.3 90.7 CSA ≤5.1 − 63.5 67.6 ≤4.15 + 55.8 79.9 DOF ≥2.0 − 69.2 73.4 ≥2.5 + 59.6 87.1 Type 2 Grade ≥2 − 52.4 91.4 ≥2 + 58.7 91.4 CSA ≤4.7 − 57.1 72.7 ≤4.15 + 54 82 DOF ≥2.0 − 63.5 74.3 ≥2.5 + 54 88.3 Predicting side of sym in patients with TN Grade ≥2 − 46.9 94.6 ≥2 + 51.9 94.6 CSA ≤4.7 − 55.6 75.7 ≤4.15 + 50.6 85.6 DOF ≥2.2 − 53.1 84.7 ≥2.5 + 49.4 91 Note:—sym indicates symptoms; −, absent; +, present.
