ORIGINAL ARTICLE Microscopic magnetic resonance in congenital diaphragmatic hernia and associated malformations in rats Montserrat Bret • Ana Lourdes Luis • Emilio Cuesta • Federica Pederiva • Rosa Aras • Leopoldo Martinez • Juan A. Tovar Published online: 24 October 2009 Ó Springer-Verlag 2009 Abstract Background/aim The research on congenital diaphrag- matic hernia (CDH) is often carried out on the nitrofen fetal rat model in which most investigations involve microdis- sections and fastidious assessment of serial sections of different anatomic areas. Current microscopic magnetic resonance (MMR) equipment allows detailed anatomic studies of alive, fresh or fixed fetuses. The purpose of the present study was to demonstrate that CDH itself and most of the associated malformations are adequately imaged and measured by MMR. Materials and methods Fetuses from pregnant rats treated with either i.g. vehicle (control, n = 10) or 100 mg nitro- fen (only those with CDH, n = 18) on E9.5 were recovered on E21 (term = E22) and total body was scanned by MMR under sedation in a 7 T MRI system (Bruker Medical, Ettlingen, Germany). CDH was detected with a coronal multislice fast spin echo sequence with a long repetition time and short effective echo time. Oblique MPR and 3D reconstructions were used. All studies were processed with attention to the hernia and its contents and the structure of the tracheobronchial tree and the lung, the heart and great vessels, the thymus and cervico-thoracic vertebrae. The findings in both groups were compared. Results Congenital diaphragmatic hernia, lung hypo- plasia and parenchymal features were clearly depicted. Tracheal ring anomalies were also demonstrated. The thymus was significantly smaller in CDH pups (2.9 9 1 9 2.4 mm) than in controls (4 9 1.3 9 2.8 mm) (p \ 0.01). MRI was particularly performant for imaging cardiovas- cular anomalies: 4 double aortic arches, 3 Fallots, 3 right aortic arches, 3 ventricular septal defects and 1 aberrant subclavian artery. Conclusions Microscopic magnetic resonance involves refined and expensive equipment but it provides a powerful research tool for the study of CDH and other malforma- tions in rat fetuses. Further work on this area is warranted. Keywords Microscopic magnetic resonance  Rat  Nitrofen  Diaphragmatic hernia  Heart  Thymus  Malformations Introduction Animal research is necessary for unveiling some of the embryologic, molecular and genetic mechanisms of the relatively frequent and often lethal malformations. Con- genital diaphragmatic hernia (CDH) and its associated defects can be reproduced in a high proportion of embryos after prenatal exposure to the herbicide nitrofen (2,4- dichloro-4 0 -nitrodiphenyl ether) and much knowledge has been gained with this reliable research tool. The patterns of both CDH and of some of the associated malformations are consistent with a mechanism involving defective neural crest cell signaling [1]. These migrating cells account for shaping the stroma of the embryonal thymus, thyroid, and Presented at the 22nd International Symposium of Paediatric Surgical Research, Genoa, Italy, 16–17 September 2009. A. L. Luis  F. Pederiva  R. Aras  L. Martinez  J. A. Tovar (&) Department of Pediatric Surgery, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain e-mail: jatovar.hulp@salud.madrid.org M. Bret  E. Cuesta Department of Radiology, Hospital Universitario La Paz, Madrid, Spain 123 Pediatr Surg Int (2010) 26:51–57 DOI 10.1007/s00383-009-2518-4