802 Table 3 Qualifying event and stroke characteristics of the PER- FORM study population Qualifying event (%) Ischemic stroke Transient ischemic attack Arterial retinal ischemic event Delay between qualifying event and randomization (%) B1 week [1 week to B1 month [1 month Ischemic stroke subtypes (%) Atherothrombotic strokea Likely atherothrombotic strokea Cardioembolic strokea Lacunar strokea Coexisting Unknown cause Modiﬁed Rankin Scale (%) Class 0 Class 1 Class 2 Class 3 Class 4 87.4 12 0.6 30 40 30 16 53 1 26 15 19 28 36 23 8 5 a Pure and coexisting cause According to the Modiﬁed Rankin Scale scores at baseline, 87% of the patients had scores B2, indicative of no or slight disability. These data were comparable to the main study popula- tion characteristics [7]. Conclusion The PERFORM MRI study is an exemplary study of a large-scale international multi-centre trial. Although such studies are expected, the complexity and difﬁculties at various levels have been hindering factors in the past. We describe the rationale, design and practical organization of a large stroke patient MRI trial. The project should provide important data on longitudinal brain disease progression with a follow-up of 2 years. Conﬂict of interest The organization of the main PERFORM study has been described at length elsewhere [6]. The PERFORM MRI Project is supervised by the MRI Scientiﬁc Committee, com- prising ﬁve members: Prof. M. Hennerici (Chairman), Prof. H. Chabriat, Prof. A. Gass, Prof. P. Maeder, and Dr. P. Michel. BioClinica, Lyon, France is responsible for the image quality con- trol, the image processing and the reading of the MR images. The authors have all received honoraria, research grants, or both from Servier. 123 J Neurol (2011) 258:795–803 Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Appendix Principal investigators from MRI centres per country Australia: C. Bladin, S. Davis, R. Helme, C. Levi, R. Schwartz; Austria: R. Schmidt, M. Vosko, J. Willeit; Belgium: P. Desfontaines, A. Michotte; Brazil: M. T. T. Da Silva, A. C. A. Ferraz, M. S. G. Rocha, J. R. C. B. Silveira; Canada: M. Hill, F. Silver, P. Teal; France: P. Clavelou, I. Crassard, T. De Broucker, C. Lamy, T. Moulin, C. Robin; Germany: J. Berrouschot, A. Grau, G. Hamann, L. Harms, R. Stingele, K. Szabo; Hungary: M. Szabo; Italy: C. Ferrarese, G. Neri, E. Parati; The Netherlands: W. M. Mulleners; Poland: J. Pniewski, K. Selmaj, A. Wajgt; Singapore: H. M . Chang, N. V . Ramani; Spain: A. Arboix Damunt, E. Diez Tejedor, O. Fernandez Fernandez, G. Izquierdo Ayuso, J. Roquer Gonzalez; Switzerland: P. Lyrer, P. Michel; Taiwan: K.-C. Chang; The United Kingdom: M. Dennis, K. Muir. MRI project investigators by country Australia: N. Ferris, S. Hudson, L. Masters, H. Prime, B. Tress; Austria: F. A. Fellner, S. Ropele, D. Zur Nedden; Belgium: T. Stadnik, L. Tshibanda; Brazil: L. Alberto Moreira De Souza, A. C. M. Maia Junior, M. S. Nacif, A. Sarmet Dos Santos; Canada: M. Heran, W. Hu, D. Mikulis; France: F. De Broucker, J. Gabrillargues, J-P. Guichard, Y. Narboux, C. Oppenheim, P. Wagner; Germany: A. Bor- mann, O. Jansen, R. Kern, R. Klingebiel, G. Layer, K. Wernecke; Hungary: E. Torok; Italy: E. Ciceri, M. Grim- aldi, P. Ottaviano; The Netherlands: D. Venderink; Poland: M. Konopka, K. Selmaj, J. Walecki; Singapore: W. E. H. Lim, Y-Y. Sitoh; Spain: L. Ballenilla, C. Caparros-Escu- dero, A. Ferna´ndez Prieto, E. Mundt, J. Perich; Switzer- land: P. Maeder, E-W. Radue; Taiwan: Y-L. Kuo; The United Kingdom: K. Muir, J. Wardlaw. References 1. Neumann-Haefelin T, Moseley ME, Albers GW (2000) New magnetic resonance imaging methods for cerebrovascular dis- ease: emerging clinical applications. Ann Neurol 47(5):559–570 2. Werring DJ, Frazer DW, Coward LJ et al (2004) Cognitive dysfunction in patients with cerebral microbleeds on T2*- weighted gradient-echo MRI. Brain 127:2265–2275