Marieke van Rosmalen

MRI of the intraspinal nerve roots in chronic inflammatory neuropathies 81 5 Intrarater reliability Table 5.3 shows the intrarater reliability. We found moderate to excellent intrarater reliability for measurements in ventral roots (ICC 0.71 – 0.91) as well as for measurements in dorsal roots (ICC 0.72 – 0.94). Table 5.3 Reliability of intraspinal nerve root measurements Site Intrarater reliability (95% CI) Ventral Dorsal C5 Right 0.84 (0.77 – 0.89) 0.83 (0.76 – 0.88) Left 0.80 (0.71 – 0.87) 0.72 (0.61 – 0.81) C6 Right 0.77 (0.64 – 0.86) 0.86 (0.80 – 0.91) Left 0.71 (0.54 – 0.82) 0.78 (0.68 – 0.85) C7 Right 0.91 (0.85 – 0.95) 0.89 (0.82 – 0.93) Left 0.83 (0.73 – 0.90) 0.94 (0.92 – 0.96) Interclass correlation coefficient (ICC) with 95% confidence interval (CI) per measurement location, i.e. at C5, C6 or C7 level, left or right, and ventral or dorsal. Mean intraspinal nerve root size per study group Mean intraspinal nerve root sizes are summarized in Table 5.4 . Nerve root sizes in patients with CIDP, MMN and MND were larger compared to healthy controls, at all predetermined sites ( p varied from < 0.001 to 0.003, Figure 5.2 ). We found no differences in the intraspinal nerve root sizes between patients with CIDP, MMN and MND, other than the right ventral root C6 patients with MMN compared to patients with CIDP ( p = 0.03). Figure 5.3 shows examples of patients with thickened intraspinal nerve roots. We established that patients with thickened intraspinal nerve roots did not necessarily have thickened cervical nerve roots in the brachial plexus ( Figure 5.3 ). Mean intraspinal nerve root sizes per clinical phenotype Mean intraspinal nerve root sizes per phenotype are summarized in Table 5.5 . In healthy controls ventral (0.53, (standard deviation (SD) 0.12)) and dorsal nerve roots (0.56 (SD 0.12)) did not differ ( p = 0.149). Dorsal nerve roots were thicker (0.67 (SD 0.16)) than ventral nerve roots (0.64 (SD 0.14); p < 0.001) in all clinical phenotypes of the chronic inflammatory neuropathies, except for patients with a pure motor presentation ( p = 0.248). Between groups we found thicker ventral nerve roots in patients with a motor phenotype compared to patients with a sensorimotor phenotype ( p = 0.018) and patients with MND ( p = 0.002). In contrast, we found thicker dorsal nerve roots in patients with a sensory or ataxic phenotype compared to patients with a sensorimotor phenotype ( p = 0.001) and patients with MND ( p = 0.006).