FULLY-AUTOMATED ESTIMATION OF UPPER CERVICAL CORD CROSS-SECTIONAL AREA USING PONTOMEDULLARY JUNCTION REFERENCING IN MULTIPLE SCLEROSIS

Roberto Masciullo¹Annine Sutter²Rosaria Sacco¹Nicola Pinna¹Daniela Distefano¹Emanuele Pravatà³Giulia Mallucci¹Alessandro Cianfoni^1,2Claudio Gobbi^1,2Chiara Zecca^1,2Giulio Disanto^1,2*

• ¹Ente Ospedaliero Cantonale (EOC), Bellinzona, Switzerland
• ²Universita della Svizzera italiana, Lugano, Switzerland
• ³Universita degli Studi Gabriele d'Annunzio Chieti Pescara, Chieti, Italy

Background: Spinal cord cross-sectional area (CSA) is a biomarker of disability in multiple sclerosis (MS). Vertebral-based CSA suffers from anatomical variability and positional bias. Objectives: To evaluate a fully automated PMJ-referenced approach, as implemented in the open-source Spinal Cord Toolbox, to assess cervical cord CSA at a fixed distance from the pontomedullary junction (PMJ) in MS. Methods: Retrospective study performed at the MS center of Lugano (Switzerland). Inclusion criteria were treatment with natalizumab or ocrelizumab and absence of clinical/radiological disease activity over ≥2 years. CSA at 64 mm caudal to the PMJ (CSA PMJ) and at C2–C3 vertebral level (CSA C2-C3) were calculated using the Spinal Cord Toolbox. Results: Seventy-five MS patients (females=44 [58.7%], age=45.1 [36.7-53.8] years, natalizumab=36 [48%], ocrelizumab=39 [52%]) were included. Median CSA PMJ and CSA C2-C3 were 57.7 (53.1-62.1) and 58.1 (53.2-62.6) mm2, respectively. The two measures were highly correlated (rho=0.95, p<0.001), with some exceptions related to errors in vertebral labelling in CSA C2-C3 assessments. PMJ was correctly identified in all subjects. CSA PMJ measures were negatively associated with disability (β=–0.08, p=0.002), independent of age and sex. Conclusions: Automated measurement of spinal cord CSA at fixed distance from the PMJ is applicable in MS, performs better than vertebral-based CSA, and correlates with neurological disability.