Lisette van Dam

Chapter 5 80 METHODS Study design and patients The Selene study was a prospective, international, multicenter diagnostic study conducted at three hospitals across three countries from December 2016 to December 2020 (NTR5738). Patients aged 18 years or older with clinically suspected UEDVT, in whom UEDVT was confirmed or excluded by a diagnostic algorithm, were included in the study. Exclusion criteria were suspected recurrent ipsilateral UEDVT, onset of symptoms of more than 10 days prior to presentation, medical or psychological condition not permitting completion of the study or signing informed consent, and general contraindications for MRI, including but not limited to a cardiac pacemaker or subcutaneous defibrillator. The study protocol was approved by the institutional review board of the Leiden University Medical Center ((LUMC) Leiden, the Netherlands), Danderyd Hospital (Stockholm, Sweden) and Østfold Hospital (Østfold, Norway). All patients provided written informed consent. Procedures Patientsweremanaged by a predefined diagnostic algorithm, consisting of a clinical decision rule (CDR) for UEDVT by Constans et al 15 , a D-dimer test and imaging including (repeat) CUS and/or (CT) venography ( Figure 1 ). 16 D-dimer levels were measured with an automated, well-validated, high-sensitivity, quantitative D-dimer assay in accordance with local guidelines (STA-Lia test or Siemens dependent on study site). UEDVT was excluded by either an unlikely clinical probability according the Constans rule in combination with a normal D-dimer test, a normal serial CUS or a normal (CT) venography. UEDVT was confirmed by a positive CUS or (CT) venography. Anticoagulant treatment was started when UEDVT was confirmed according to local protocols. In all patients with confirmed (group 1) or excluded UEDVT (group 2) MR-NCTI, including both MRDTI and 3D-TSE SPAIR sequences, was performed within 48 hours of the initial diagnosis. MRI scans were performed with a 1.5 or 3.0 Tesla unit using an integrated 16-channel posterior coil and a 16-channel anterior body coil for signal reception. 9,10,17 The complete MRDTI and 3D-TSE SPAIR sequence