Lisette van Dam

MRI for diagnosis of recurrent ipsilateral DVT 2 25 Table 3. Primary outcome of the study. Category Patients (n) Incidence of the primary outcome (%, 95%CI) Patients with MRDTI negative for both DVT and thrombophlebitis who were not treated with any anticoagulant during follow-up * 119 1.7 (0.20-5.9) All patients with MRDTI negative for DVT 189 1.1 (0.13-3.8) *Patients who developed thrombophlebitis during follow-up were not included in this cohort because they received a course of anticoagulant treatment. Reference CUS All 189 patients with MRDTI negative for DVT were subjected to a reference CUS examination after the treatment decision was made, showing incompressibility in 88 (47%). In the report of these reference CUS examinations, it was mentioned specifically that recurrent DVT was likely or could not be excluded in 57 patients (30%). Notably, prior CUS examinations for comparison were only available in 90 patients with MRDTI negative for DVT (48%). Of these 90 patients, recurrent DVT was likely or could not be excluded in 24 (27%). Secondary outcomes The agreement between initial local reading and post-hoc central reading of the MRDTI images was excellent (kappa statistic 0.91). Among the 444 screened patients, only 16 patients (3.6%) could not be included because the MRDTI was not available or possible to perform within 24 hours. The median time from study inclusion to performing the MRDTI was 4 hours (interquartile range 2-22 hours). DISCUSSION Our study demonstrates that the incidence of VTE recurrence after negative MRDTI was low. The failure rate among patients with baseline MRDTI negative for DVT who remained without anticoagulant treatment during follow-up was 1.7%,