HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Paturneau-Jouas, M. Articles by Leroy-Willig, A. Search for Related Content PubMed PubMed Citation Articles by Paturneau-Jouas, M. Articles by Leroy-Willig, A.

Electrotransfer at MR Imaging: Tool for Optimization of Gene Transfer Protocols—Feasibility Study in Mice¹

¹ From INSERM U 582 (M.P.J., J.T.V., K.S.) and Laboratoire de RMN (AFM-CEA) (E.P., G.V., P.G.C., C.W., A.L.W.), Institut de Myologie, Hôpital de la Pitié-Salpêtrière, 47 Boulevard de l’Hôpital, 75651 Paris, France; and Service de Radiologie, Hôpital Saint-Louis, Paris, France (E.d.K.). Received April 26, 2002; revision requested July 9; final revision received December 4; accepted January 13, 2003. Supported by the Association Française contre les Myopathies, the Institut Fédératif de Recherche 14, the Institut National de la Santé et de la Recherche Médicale, the Commissariat à l’Energie Atomique, and the Centre National de la Recherche Scientifique. E.P. supported by the Ministère de la Recherche. Address correspondence to A.L.W. (e-mail: a.leroywillig@myologie.chups.jussieu.fr).

View larger version (93K): [in a new window]   Figure 1. In vivo MR images at day 3 after electroporation in animals of groups 1-3. Transverse spin-echo T1-weighted images (700/11) of control and electroporated legs of animals of groups 1 (A, B), 2 (C, D), and 3 (E, F). A, C, E, Images of contralateral control legs of the animals do not exhibit signal intensity variation. B, D, F, Images of electroporated treated legs show areas of increased signal intensity that mostly reflect the accumulation of gadopentetate dimeglumine. B, Electroporation after intraperitoneal injection of the contrast agent. In the presence of extracellular gadopentetate dimeglumine, muscle signal intensity is increased, with a complex pattern through a large fraction of leg section. Intermuscular aponeurosis and a central zone show lower signal intensity. D, Electroporation before intraperitoneal injection of gadopentetate dimeglumine. Muscle signal intensity is very faintly increased. F, Electroporation after intramuscular injection of gadopentetate dimeglumine. Muscle signal intensity increase is strong but distributed into a smaller volume compared with that in B.

View larger version (15K): [in a new window]   Figure 2. Graph depicts signal intensity variations measured in vivo on T1-weighted images of electroporated treated legs, normalized to that of the control legs, in groups 1-3. In groups 1 and 3, a strong signal intensity increase () is measured in ROIs of treated legs normalized to corresponding ROIs of control legs (mean value, 1.64 ± 0.2 and 1.58 ± 0.17, respectively). In group 2, the mean signal intensity increase is much weaker (mean value, 1.16 ± 0.06). It is related to the contamination of T1-weighted images by T2 variation. Signal intensity increase corrected for T2 values () is measured in the same ROIs of treated legs and control legs (mean value, 1.47 ± 0.19 in group 1 and 1.04 ± 0.09 in group 2). Bars indicate mean ± SD of signal intensity increase.

View larger version (135K): [in a new window]   Figure 3. MR images at day 3 in two mice of groups 1 and 2. Transverse spin-echo T2-weighted images (1,100/50) of control and electroporated legs of one animal of group 1 (A, B) and one animal of group 2 (C, D). A, C, Control legs of the animals do not exhibit signal intensity variation. B, D, MR signal intensity increase is observed in electroporated areas. It reflects both the accumulation of gadopentetate dimeglumine, which increases signal intensity, and tissue modification, which increases T2 and also signal intensity at high echo time. B, In group 1 animal, topography of signal intensity increase is similar to that observed in Figure 1, B. D, In group 2 animal, signal variation exhibits similar topography but weaker intensity, reflecting that only T2 variation is involved.

View larger version (48K): [in a new window]   Figure 4. Comparison of ex vivo T1-weighted images with the corresponding histologic images of group 3. MR image of the central slice through the removed gastrocnemius muscle and the corresponding histologic section are displayed for the treated legs of the five mice (1-5) of group 3. Magnification is the same for all images. Differences between animals in shape and size of the labeled territories are obvious with both techniques. For each animal, a clear similarity is observed between the area where muscle MR signal intensity is increased through intracellular trapping of gadopentetate dimeglumine and the area where expression of the reporter gene is revealed with staining. (X-Gal blue stain; original magnification, x6.8.)