COMMENTARY Open Access Effectively incorporating selected multimedia content into medical publications Alexander Ziegler1*, Daniel Mietchen2, Cornelius Faber3, Wolfram von Hausen4, Christoph Sch��bel5, Markus Sellerer6, Andreas Ziegler1 Abstract Until fairly recently, medical publications have been handicapped by being restricted to non-electronic formats, effectively preventing the dissemination of complex audiovisual and three-dimensional data. However, authors and readers could significantly profit from advances in electronic publishing that permit the inclusion of multimedia content directly into an article. For the first time, the de facto gold standard for scientific publishing, the portable document format (PDF), is used here as a platform to embed a video and an audio sequence of patient data into a publication. Fully interactive three- dimensional models of a face and a schematic representation of a human brain are also part of this publication. We discuss the potential of this approach and its impact on the communication of scientific medical data, particularly with regard to electronic and open access publications. Finally, we emphasise how medical teaching can benefit from this new tool and comment on the future of medical publishing. Editorial note During proofing and production of this article, there was significant debate about whether the multimedia files should be included as figures or additional files. We have taken the view that readers and indexers currently expect figures to be 2D graphical images suitable for printing, which is not the case with these files. The mul- timedia files are embedded into the PDF version of the article, and downloadable from links in the HTML ver- sion of the article. This article may act as a catalyst for Publishers to agree on the best way to present multime- dia content. Introduction Despite substantial improvements since the early attempts of anatomists during the Renaissance, medical illustrations have always been handicapped by being restricted to two dimensions (2D). Comparable, but even more severe limitations have prevented the distri- bution of moving images as well as sounds through medical publications. A common solution to communi- cate complex multimedia data currently relies on the creation of supplemental files that are available for download either through the publisher���s or the author���s website. However, this results in the unattractive separa- tion of the actual publication from supporting multime- dia data, which may contain crucial information (see [1] for an example). As electronic publishing gains momen- tum, it seems logical to fully exploit its potential by inte- grating multimedia and text files into a single article. While online publishing formats are gaining popular- ity, there can be no doubt that the current standard in electronic publishing is the portable document format (PDF). Since June 2008, this file type provides also the possibility to integrate three-dimensional (3D), video, and audio content together with the text into a single file. Strangely, the potential of this technique does not seem to have been recognised so far in the field of med- ical publishing, while astronomers [2], chemists [3], structural biologists [4,5], as well as zoologists [6,7] have already exploited the many opportunities offered by this approach. Using examples from various medical disci- plines, we demonstrate how the readers of medical pub- lications can profit from embedded multimedia content. We also point out some of the opportunities that are now available for medical publishing in general. Interactive 3D imagery embedded into publications To highlight the improvements that are attainable, we present here two fully interactive 3D models. The model of a face that is integrated into this article (Additional * Correspondence: alexander.ziegler@charite.de 1Institut f��r Immungenetik, Charit��-Universit��tsmedizin Berlin, Freie Universit��t Berlin, Berlin, Germany Full list of author information is available at the end of the article Ziegler et al. BMC Medicine 2011, 9:17 http://www.biomedcentral.com/1741-7015/9/17 �� 2011 Ziegler et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

file 1) illustrates that the ability to freely manipulate a 3D structure, for example by zooming in on particular characteristics, offers interesting opportunities for a range of medical disciplines, since, for example, the shape of individual anatomical features of the skin could be apprehended by the reader in a truly interactive fash- ion. In contrast, the semischematic, surface-rendered 3D model of a human brain that is based on a magnetic resonance imaging dataset (Additional file 2) is intended to serve as an example of a greatly simplified anatomical representation of a human organ in 3D. In addition to colour coding, individual components have been labelled using so-called 3D mark-ups. Interactive 3D imagery of human organs such as, for example, the brain is also available through the web (Table 1). However, most of the freely accessible brain models can be viewed only while the user is online, or require the installation of specialised software. In addition, certainly the greatest disadvantage of many of the models on offer is that they do not permit the viewer to ���take possession��� of the visualisations and to disseminate them in any way desired. In contrast, the advantages of the approach implemen- ted here include (i) the full integration of the entire 3D model into the final publication, (ii) an intuitive, interac- tive form of access to the embedded model online as well as offline, (iii) the opportunity to disseminate the embedded model as desired, and (iv) the possibility to generate views and representations not predetermined by the author(s) of the manuscript, as would be the case, for example, in a video. Audiovisual content embedded into publications The strength of videos, however, rests in their ability to convey time-dependent changes within an image, which is exemplified by a short video sequence embedded into this article (Additional file 3). Clearly, the possibility to integrate videos is likely to find a wide range of applica- tions in medical publishing. As we show here, this is particularly evident in cardiology. Audio sequences can be integrated into a PDF as well. As an example, we present a striking case of sleep apnoea (Additional file 4). As in the case of videos, the integration of audio files into a publication might be of considerable interest for practitioners in several medical fields. For instance, doc- umenting phenotypic variations in genetic disorders, such as in different variants of cri du chat syndrome [8], provides an example for the application of this techni- que. Readers not familiar with the use of PDF-embedded multimedia content will find a brief explanation towards the end of this article. Impact on medical publishing The opportunities offered by embedding multimedia files have a number of foreseeable implications for pub- lications that communicate medical data. From a scienti- fic point of view, the greatest asset is presumably that the transparency of the presented data can be expected to increase, while the need for explanatory supplemental material will largely become obsolete. In recognising these opportunities, the Journal of Neuroscience has recently decided to ban supplemental material altogether [9]. Instead, authors are encouraged to ���publish articles with embedded movies or three-dimensional models, both online and in downloadable PDFs���. PDF files with embedded multimedia content are available as a single download and may be viewed online as well as offline at the reader���s discretion. As stressed by the editor of the Journal of Neuroscience, this new policy ���eliminates the only essential role of supplemental material��� and is meant to strengthen the desirable concept of an article as ���a complete, self-contained scientific report��� [9]. Click for 3D Additional file 1 Portable document format (PDF)-embedded, interactive three-dimensional (3D) model of a face. The 3D model was generated using an optical face scanner (FaceSCAN3D, 3D-Shape GmbH, Erlangen, Germany). This system measures the 3D shape of an object in less than a second using projected light patterns and a set of cameras. Applications of this methodology may include, for example, before and after surgery comparisons and the documentation of dermatological or orthopaedic patient characteristics. Scanning was performed on a healthy male volunteer. Activation of the embedded multimedia content requires the use of a PDF reader compatible with version 1.7 Extension Level 3 (for example Adobe Reader 9). Use the ���+/- zoom��� or ���toggle full- screen��� options in order to maximize window size. Ziegler et al. BMC Medicine 2011, 9:17 http://www.biomedcentral.com/1741-7015/9/17 Page 2 of 6