**Description** While dynamic contrast enhanced (DCE-) MRI has been widely used to evaluate diverse brain pathologies, there is a lack of standardized analysis methods, limiting its application in clinical practice, multi-institutional studies, or clinical trials. The Open-Science Initiative for Perfusion Imaging (OSIPI), an initiative of ISMRM perfusion study group and sponsored by ISMRM, was founded to promote reproducible research and open science in perfusion imaging and facilitate translation of software tools into clinical practice. In accordance with the aims of OSIPI, we have designed the DCE (OSIPI-DCE) challenge for evaluating DCE-MRI methods that estimate the volume transfer constant (Ktrans) in brain tumors. **Challenge Overview** The analysis methods submitted by the competing teams will be evaluated and compared withe each other for quantification of Ktrans from DCE-MRI in terms of accuracy, repeatability, and reproducibility. The accuracy of Ktrans estimations by the participating teams will be scored based on synthetic data, i.e., 2 digital reference objects (DROs) each including 2 visits, specifically designed for this challenge; repeatability will be rated based on test-retest DCE-MRI scans of 8 patients from RIDER Neuro MRI Database; reproducibility will be assessed based on an independent analysis by a neutral team. The submissions will be ranked according to a global score reflecting that an ideal method should be accurate AND repeatable AND reproducible. The results of the challenge will be announced in the Perfusion Study Group Workshop in February 2022, and the top three teams will present their methods at the ISMRM 2022 annual meeting. Teams will register for free on http://challenge.ismrm.org (the link to the DCE challenge webpage: https://challenge.ismrm.org/forums/topic/osipi-dce-challenge/; registration form: https://challenge.ismrm.org/2021-osipi-dce-registration/). Upon registration, they receive submission guidelines and a link to the data, which is uploaded in this repository. When you are ready to submit your results, submit a .ZIP file including your Ktrans maps in NifTI format and an accompanying document (Standard Operating Procedures (SOPs)) here: https://ismrm.sharefile.com/r-rb1013490f2df44b6a180f88eab861427. At the end of the challenge, all the submissions will be processed and evaluated by the organizing team. ![OSIPI-DCE Challenge Flyer][1] [1]: https://osf.io/zts95