DOI: 10.1148/rg.276075054
RadioGraphics 2007;27:1839-1844
© RSNA, 2007
INFORMATICS
Recording, Editing, Archiving, and Distributing Radiology Lectures: A Streamlined Approach
Derk D. Purcell, MD,
Christopher P. Hess, MD, PhD,
Jeremy C. Durack, MD, and
Richard S. Breiman, MD
1 From the Department of Radiology, University of California San Francisco, 505 Parnassus Ave, Box 0628, M-392, San Francisco, CA 94143-0628. Presented as an Informatics exhibit at the 2006 RSNA Annual Meeting. Received March 26, 2007; revision requested May 18 and received June 25; accepted July 20. All authors have no financial relationships to disclose.
Address correspondence to D.D.P. (e-mail: derk.purcell{at}radiology.ucsf.edu).
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Abstract
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Recent advances in digital recording technology have simplified the recording of audio, video, and image information from didactic radiology conferences. Recording lectures in a suitable digital format has several advantages, including the ability to edit lecture content, combine lectures conducted at different times and places, store media digitally, and broadcast conferences electronically over the Internet. An inexpensive, commercially available conversion device was developed that allows straightforward capture and compression of multimedia audiovisual information, thus facilitating the use of this information by the conference presenter as well as the end user. A converter is connected to a personal computer (PC) by means of standard connections, and editing and compression of digital media are performed on the PC prior to their distribution and archiving. The result is a high-quality, highly compressed file that can be played back from any PC and from many portable video devices. This approach represents a simple and cost-effective means of creating and maintaining a library of didactic lectures for students and trainees in radiology.
© RSNA, 2007
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Introduction
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Although much of radiology training takes place in the reading room or through self-directed learning, didactic conferences that feature digital slide shows are one of the primary means of formal training in diagnostic radiology residency programs. The ability to capture didactic conferences in digital formats enables programs to develop high-quality teaching libraries for later review. Low-tech approaches involving video cameras directed at projected slide shows suffer from low resolution and high cost, the latter due to additional labor and personnel requirements. Direct digital capture of digital slide shows with Power-Point (Microsoft, Redmond, Wash) or Keynote (Apple Computer, Cupertino, Calif) has recently become possible, resulting in higher-resolution video recordings, simplified storage and distribution of digital media, and minimal ongoing administrative cost once the recording-encoding infrastructure has been installed. Some systems require separate audio and video capture mechanisms, necessitating the use of dedicated hardware and software to combine audio and video feeds. To our knowledge, the practice of digitally recording teaching sessions in radiology has not been discussed in the medical literature.
In this article, we describe a system for capturing didactic conferences in digital formats that we developed for our large residency program. In addition, we discuss user experience and output quality with typical didactic lectures captured with this system. Furthermore, using this system as a model, we explore potential platforms for the distribution, viewing, and archiving of digital teaching material. The proposed system is simple to implement and promises to improve radiology teaching sessions for medical students, residents, and postgraduate students.
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Recording a Lecture
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Background and Equipment
The essential components of a digital slide presentation are the slide content, the slide progression, and the presenter’s voice. Slide content may consist solely of textual information but typically also includes high-quality digital images or video clips. During the actual lecture, the presenter defines the slide progression by advancing between slides. To capture slide content and progression, the standard video graphics array (VGA) output from the presenter’s personal computer (PC) is split into two signals. One feed is routed to the digital projector, and the other feed is routed to the digital video converter (DVC). Our system makes use of a VGA2USB converter (Epiphan Systems, Ottawa, Ontario, Canada), which is widely available and ships with all of the necessary cables. Although this converter is compatible with both Mac OS (Apple Computer) and Windows (Microsoft) operating systems, we currently use a Macintosh system as the "encoder" PC. The actual digital recording is performed on this system using two software packages: BTV (www.bensoftware.com) for video capture and QuickTime Pro (Apple Computer) for processing. Not including the cost of the presenter and encoder PCs, the total cost of the DVC and software is approximately $350.
Hardware Setup
Once the presenter PC is properly connected to the projector by means of the VGA cable and the projected slide appears on the screen, the VGA cable is disconnected from the projector. The VGA splitter is then inserted between the cable and the projector, at which time the image should again appear on the screen. The second VGA output is then connected to the DVC, and the output from the DVC is connected to the encoder PC with a universal serial bus (USB) plug (Fig 1). To record audio, we used the built-in microphone in the encoder PC, but an external microphone could be used to improve sound quality and reduce background noise. Note that neither the speaker nor the presenter PC is affected by the system.
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Figure 1. Schematic illustrates the hardware setup. Presenter PC–VGA output is split and connected to a DVC and a digital projector. Converted output from the DVC is then fed into the encoder PC.
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Software Setup
Next, the BTV software package must be started on the encoder PC. Once the proper connection is made, the BTV window and capture controls will appear and display the same image projected by the liquid crystal display projector (Fig 1). The BTV software allows the user to choose different file types for video capture and adjust the frame rate and image quality (Settings 
Video settings) (Fig 2). Obviously, higher frame rates and image quality settings will increase the size of the captured video file (Table 1). We record at the highest quality ("Best" setting), knowing that the file can be compressed at a later date depending on its intended use (eg, archiving, large-screen display, portable video display). Audio gain (Settings Sound settings) should be adjusted to optimize the speaker’s voice and minimize background noise (Fig 3). Although a "Middle" setting is often adequate, a simple adjustment during sound check will correct for differences in speaker and microphone interaction.
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Figure 2. Screen shows the Video settings window, which allows the user to select different file types for video capture (small arrow) and adjust the frame rate (arrowhead) and image quality (large arrow).
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With the video and audio settings properly adjusted, recording of the lecture can begin. Clicking on the "Capture video" button in the Capture Controls window starts the recording. A minute timer will appear in the Capture Controls window once recording has commenced (Fig 4). We encourage our speakers to use (whenever possible) a mouse-controlled arrow to point within the slide show, since a laser pointer aimed at the projector screen will not be captured with this method.
When the lecture has ended, the "Stop capturing movie" button in the Capture Controls window is selected (Fig 4). The movie file will be deposited onto the desktop, labeled "BTV Movie 001.mov." Subsequent recordings will be labeled "BTV Movie 002.mov," "BTV Movie 003.mov," and so on; however, we recommend renaming the file for future archiving and editing purposes (eg, "MRI_Brain.Tumors_DDPurcell_2.11.2007 .mov").
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Video File Processing and Compression
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Compressing the original video files allows decreased storage requirements, reduced transfer times, and the potential for portable viewing on a laptop computer or video iPod (Apple Computer). With the relatively low cost of mass data storage devices (eg, external hard drives, digital video disks), one could elect to maintain an archive of the original recordings. However, significant reductions in file size can be achieved without appreciable reduction in image quality.
There are many programs capable of video conversion and compression. For our implementation, QuickTime Pro (Apple Computer) was selected due to its ease of use, low cost, and availability for both Mac OS and Windows operating systems. First, the movie file is opened with QuickTime Pro. Audio and video content captured before or after the presentation can be trimmed using the calipers in the progress bar at the bottom of the viewer window by placing the calipers on either side of the desired content and choosing "Trim to selection" from the "Edit" drop-down menu.
The next step is to optimize the file for the intended purpose. For archiving, in lieu of the original uncompressed file, we use a compressed Moving Picture Experts Group (MPEG)-4 format that is suitable for both high-quality–large-screen viewing and archiving purposes. With the original movie file open in QuickTime Pro (Apple Computer), select "Export" from the "File" drop-down menu. The "Save exported file as. . ." window will open. Select "MPEG-4" from the "Export:" drop-down menu, then select "LAN/Intranet" or "Broadband-High" from the "Use:" drop-down menu. For optimizing smaller files for viewing on portable video devices, select "Broadband-Low" (Fig 5). Alternatively, select "iPod" from the "Export:" drop-down menu. Note that these are only suggested settings; we routinely tailor the video file size and quality settings depending on lecture content and desired use (Table 2).
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Distribution and Archiving
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The low cost of off-line storage options (eg, external hard drives, optical media) makes archiving a relatively simple and inexpensive task. At our institution, the original uncompressed files are saved on an external hard drive in the department library. Users can view the video files on password-protected computers or download selected lectures to their own portable storage device (eg, USB drive). Compressed versions are also uploaded to the department server for online access anytime. The file names include the date, the speaker’s name and division, and an abbreviated title, thereby allowing rapid browsing of available lecture topics. Access to this network is password protected. Another option for online distribution would be podcasting (1), a form of online media broadcasting.
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Discussion
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Our approach to digitally recording multimedia lectures is both simple and affordable. The captured video files afford excellent resolution and ready portability. Archived lectures allow trainees to view lectures missed due (for example) to clinical responsibilities, postcall days, sick leave, or vacation.
Another benefit of recorded lectures is the ease of providing access to teaching sessions at multiple sites, a challenge faced by many teaching institutions (2). The high cost of video teleconferencing equipment and administration may be a significant obstacle to the implementation of lecture capture for many of these programs (3). The benefits of digitally recorded lectures include more efficient use of the instructor’s time, whose presentations are now available to learners at other sites and whose travel time can now be devoted to other more productive activities.
Despite offering many benefits, the system in its current form does not include video of the speaker. Another limitation of the system is that it requires trained personnel for hardware setup, software operation, and post hoc editing and compression of the video files. At our institution, a resident (D.D.P.) currently handles the setup, recording, editing, and archiving. With the required software installed, the system can be made ready for recording in the time it takes to connect the proper cables and splitter, boot up the encoder PC, and start the BTV program (<5 minutes). The time required for video compression and uploading to the server may vary depending on the specifications of the encoder PC and network; however, neither task requires much time or effort. In the future, automated recording and real-time video compression may be incorporated to reduce personnel requirements.
Although not unique to our system, a potential drawback to lecture recording is the risk of plagiarism and unauthorized sharing or selling of the lecture content. Distributing the original slide show files allows capture of high-quality images that could be reused without the presenter’s permission. One possible solution would be to intentionally compromise video resolution with the goal of creating video files that are adequate for lecture review on a PC but inadequate for image capture and publishing. Alternatively, the files could be uploaded to a server for password-protected streaming.
Our preliminary experience indicates that the system is reliable. On one occasion, the encoder PC "froze," necessitating a reboot. The source of this malfunction was not clear; however, the encoder PC and recording system were restarted successfully. Neither the speaker nor the presenter PC was affected.
Software solutions such as Camtasia Studio (TechSmith, Okemos, Mich), Apresso (Anystream, Sterling, Va), and Profcast (Humble Daisy, Ann Arbor, Mich) allow slide show capture (including audio synced with slide progression or animation and mouse movements); however, these programs must be installed on the presenter PC. At our institution, a large majority of the speakers present lectures using their own PCs. In addition to the significant cost of multiple software licenses, the logistics of managing (ie, editing, archiving, and distributing) the video files from multiple PCs would be too cumbersome. Our single hardware-software solution works well as an inexpensive, portable, and centralized recording system.
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Conclusions
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Advances in digital recording technology have simplified the recording of audio, video, and image information from didactic radiology conferences. Our approach represents a simple and cost-effective means of creating and maintaining a library of didactic lectures for students and trainees in radiology.
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TAKE-HOME POINTS
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The ability to capture didactic conferences in digital formats enables programs to develop high-quality teaching libraries for later review.
- Low-tech approaches involving video cameras directed at projected slide shows suffer from low resolution and high cost, the latter due to additional labor and personnel requirements.
- Archived lectures allow trainees to view lectures missed due (for example) to clinical responsibilities, postcall days, sick leave, or vacation.
- Another benefit of recorded lectures is the ease of providing access to teaching sessions at multiple sites, a challenge faced by many teaching institutions.
- Although not unique to our system, a potential drawback to lecture recording is the risk of plagiarism and unauthorized sharing or selling of the lecture content.
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Footnotes
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Abbreviations: DVC = digital video converter, PC = personal computer, USB = universal serial bus, VGA = video graphics array
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References
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- Rowell MR, Corl FM, Johnson PT, Fishman EK. Internet-based dissemination of educational audiocasts: a primer in podcasting—how to do it. AJR Am J Roentgenol 2006;186:1792–1796.[Abstract/Free Full Text]
- Martin VL, Bennett DS. Creation of a web-based lecture series for psychiatry clerkship students: initial findings. Acad Psychiatry 2004;28:209–214.[Abstract/Free Full Text]
- Stain SC, Mitchell M, Belue R, et al. Objective assessment of videoconferenced lectures in a surgical clerkship. Am J Surg 2005;189:81–84.[CrossRef][Medline]
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Abstract
Introduction
