The 1000Plus study protocol – a prospective observational study on the mismatch concept in a 3.0 T MRI

Background: Stroke MRI and the mismatch of DWI lesion and perfusion imaging (PI) deficit volumes may help to replace CT guided selection for thrombolysis based on a rigid time frame and hemorrhage exclusion. Two studies, DEFUSE and EPITHET, investigated the mismatch concept with relatively low recruiting rates. Therefore, confirmation of the positive results in a larger cohort is desirable. Provided with a purely research dedicated 3T MR scanner installed on the neurologic ward we are able to screen all patients with a suspected cerebrovascular event. We hypothesize that the prognostic value of the mismatch concept strongly depends on vessel status and stroke-to-MRI time.

Methods: 1000Plus is designed as a prospective, single centre observational study with a recruiting goal of 1200 patients. All acute cerebrovascular events admitted to the hospital within a time frame of 24h after onset of symptoms are screened. Patients not able to give informed consent at time of admission receive an MRI for individual benefit. Further examinations are performed on the following day and 5–7 days after onset to assess final infarct size. Every examination contains pre-MRI NIHSS scoring and the following sequences: T2*, DWI, TOF-MRA, FLAIR and on days 1 and 2 PI. Perfusion images are obtained by dynamic susceptibility-enhanced contrast imaging with a fixed dose of 5ml 1M Gadobutrol (except for weight ≥100kg 6ml/weight ≤50kg 4ml). By the use of PMA Software (version 3.1 or newer) from ASIST-Japan, MTT parametric images are determined by deconvolution of the automatically identified arterial input function. Primary endpoint is the change of infarct size between baseline and day 5–7 examination.

Results: Interim analysis results will be presented at the DGN.