Marieke van Rosmalen

Chapter 4 62 Table 4.2 Rate of overall successful measurements per nerve root on brachial plexus MRI performed by one rater Nerve root Coronal Sagittal Ganglion 1 cm Ganglion 1 cm C5 Right 120 (97.5%) 100 (81.3%) 115 (93.5%) 74 (60.2%) Left 119 (96.7%) 85 (69.1%) 110 (89.4%) 56 (45.5%) C6 Right 120 (97.5%) 96 (78.0%) 120 (97.5%) 89 (72.4%) Left 122 (99.2%) 87 (70.7%) 118 (95.9%) 66 (53.7%) C7 Right 118 (95.6%) 73 (59.3%) 116 (94.3%) 68 (55.2%) Left 119 (96.7%) 70 (56.9%) 114 (92.7%) 60 (48.8%) Number of measurements performed per nerve root differed between coronal and sagittal plane due to lower image quality, and between measurement site (next to ganglion or 1 cm distal from ganglion) due to merging or dividing of nerve roots. Intra- and interrater reliability Table 4.3 shows the intraclass correlation coefficients (ICC) within and between raters. We found moderate to good intrarater reliability in both plane orientations (ICC 0.55 – 0.87 in coronal plane, and 0.63 – 0.86 in sagittal plane). We found moderate to good interrater reliability in the coronal plane (ICC 0.65 – 0.90) but a poor to good reliability in the sagittal plane (ICC 0.47 – 0.84). Overall, we found higher consistency in measurements performed in the coronal plane orientation. Table 4.3 Reliability of nerve root measurements on brachial plexus MRI Site Intrarater reliability Interrater reliability Coronal Sagittal Coronal Sagittal C5 Ganglion 0.81 (0.74 – 0.86) 0.69 (0.58 – 0.77) 0.81 (0.58 – 0.92) 0.52 (0.09 – 0.78) 1 cm 0.55 (0.41 – 0.67) 0.63 (0.47 – 0.74) 0.78 (0.51 – 0.91) 0.62 (0.14 – 0.87) C6 Ganglion 0.77 (0.69 – 0.84) 0.68 (0.58 – 0.77) 0.77 (0.37 – 0.89) 0.47 (0.04 – 0.75) 1 cm 0.84 (0.77 – 0.89) 0.83 (0.74 – 0.88) 0.82 (0.58 – 0.93) 0.79 (0.50 – 0.92) C7 Ganglion 0.78 (0.70 – 0.84) 0.75 (0.67 – 0.82) 0.65 (0.13 – 0.87) 0.73 (0.44 – 0.89) 1 cm 0.87 (0.81 – 0.91) 0.86 (0.79 – 0.91) 0.90 (0.60 – 0.97) 0.84 (0.35 – 0.96) Intraclass correlation coefficient (ICC) with 95% confidence interval for every measurement site in coronal and sagittal planes. Mean nerve root size Mean nerve root sizes are summarized in Table 4.4 . Nerve root sizes in patients with CIDP and MMN were larger compared to disease controls, at all predetermined anatomical sites ( p varied from < 0.001 to 0.026).