Marieke van Rosmalen

Chapter 4 64 The added value of MRI ROC analysis showed that at a set specificity of 95%, the sensitivities are 27% for G 0 and 17% at G 1 . With this specificity, a probability of ≥ 61% for measurements at G 0 and ≥ 69% at G 1 in the risk chart were considered abnormal or likely to have a chronic inflammatory neuropathy ( Figure 4.3 ). With these cut-off values, we determined which patients in our data set had an abnormal MRI and we investigated the added value of brachial plexus MRI in addition to NCS and nerve ultrasound. We found that NCS combined with nerve ultrasound identified most patients with an inflammatory neuropathy. The majority of patients with abnormal ultrasound findings also had abnormal MRI findings ( Figure 4.4A and B ). However, 5/50 (10%) patients with CIDP had an abnormal MRI result, while NCS did not fullfill the criteria for CIDP and ultrasound did not show abnormalities. All patients had a good response to treatment. Clinical symptoms and laboratory findings of these 5 patients are summarized in Table 4.5 . MRI did not have any added diagnostic value for MMN. Figure 4.2 ROC analysis of nerve root size measurements on MRI C5 C6 C7 Reference line Sensitivity Sensitivity 1 – Specificity 1 – Specificity AUC = 0.78 (95%CI 0.69 – 0.87) AUC = 0.81 (95%CI 0.72 – 0.91) Sensitivity C5 C6 C7 Reference line A B Sensitivity C D ROC curves of measurements per nerve root next to the ganglion (A) and 1 cm distal of the ganglion (B) are shown in the upper panels. Combined ROC curves of measurements next to the ganglion (C) and 1 cm distal of the ganglion (D) are shown in the lower panels. Combined measurements are expressed as area under the curve (AUC) and 95% confidence interval (CI).