Radiology Case Study Ppt Sample
Import Video Files Successfully
Static images are sometimes insufficient to effectively depict complex three-dimensional (3D) anatomy or dynamic viewing methods, such as cine loops obtained with ultrasonography or angiography. Even simple cross-sectional images can be made more engaging if you display a stack of images serially, allowing your audience to make the diagnosis as they would at a PACS workstation. Most radiology workstations provide a means of exporting cine and image stacks either as video files in the common AVI (audio-video interleave) or MPEG (Moving Picture Experts Group) video file formats or as folders of serial static images. PowerPoint allows you to insert video files onto a slide via the same menu-based commands used for single images and, if all goes well, these video files will run smoothly when the slide is displayed. However, seeing video fail during a PowerPoint presentation is an aggravation most everyone has experienced at radiology meetings, whether at the podium or in the audience.
Sometimes, the causes for these frustrating occurrences are within the user’s control, but other times they are not. Unlike video, image files are rarely problematic because once they are inserted, a copy becomes embedded within the main PowerPoint file so that the original file is no longer required. For video, however, a link is created from a slide to the location of the file on the computer hard drive, portable memory device, or network storage. Unfortunately, it is too easy to sever the link to these files, particularly when transferring documents between different folders on your computer or when transferring your presentation files onto the central servers, which are becoming increasingly common at larger meetings.
Even if you are diligent in keeping your media intact, the conference presentation system you are using may fail to play the videos. This is often the result of unsupported or missing codecs, which are critical files for decompressing video for playback that must be preinstalled on the presentation system. There is huge variability among these files and in how widely they are installed, so you cannot assume that your preferred video format will play without testing. Unfortunately, there is often scant opportunity to do a practice run in the presentation hall, and what works in the speaker preparation room does not always display properly before the actual audience. A way of incorporating moving sequences while avoiding video files altogether is discussed later in this article.
A third major cause of video playback glitches is file size, which can easily run into the tens of megabytes depending on length, resolution, format, and compression codec. Older and inexpensive computers, including the portable class of netbooks, have slower processors for handling video. Running the presentation from an external storage device such as a USB (universal serial bus) thumb drive can exacerbate the problem, causing video to stutter, and it can even crash the system entirely.
Understanding and planning around these typical video playback pitfalls can help increase the chances of video playback success. Technical issues for importing and editing video clips into radiology presentations are discussed in greater detail in a useful two-part series by Yam et al in the American Journal of Roentgenology (2,3).
A More Reliable Alternative to Video: Animated Graphic Interchange Files
What if there was a way of reliably incorporating cine loops and other motion clips into a PowerPoint presentation while avoiding the use of video files altogether? Surprisingly, this is indeed possible if one converts video files or image series into an image format known as an animated graphic interchange file (GIF). This widely compatible file format is used to create animated sequences in a small size footprint and was one of the first elements to provide World Wide Web users with a dynamic experience. Although people may be more familiar with animated GIFs as simple moving cartoonlike figures on Web pages, they are indeed able to meet the spatial and temporal resolution requirements for video in most radiology presentations. In addition to assurance of video playback during your presentation, there are additional benefits that come with the use of animated GIFs. One can expect around a 10-fold reduction in file size compared with linked video files, and animated GIFs can be embedded in your main PowerPoint presentation file just like normal JPEG (Joint Photographic Experts Group) images and other static image formats. Unlike linked video files, animated GIFs can be adjusted for size, brightness, contrast, and rotation. One can even place text, arrows, and other annotations over the animated GIF sequence. This is impossible with video files, which always superimpose over any other slide elements. A step-by-step method that uses Adobe Photoshop (Adobe Systems, San Jose, Calif) to convert video into animated GIFs is described in another excellent article by Yam et al (4). A free alternative for those who do not own the expensive Photoshop application is Beneton MovieGIF, which converts image stacks and video files to the animated GIF format easily. After loading one’s files and selecting the desired frames, the speed of playback (Fig 1a) and the number of times the animation loops (Fig 1b) can be easily set.
Figure 1a:(a, b) Screenshots show Beneton Movie GIF, a free application used to convert video files or image series into animated GIFs. (a) You can change playback speed by setting the delay between selected frames (type Ctrl-A first to select all frames). (b) When saving an animated GIF, you are given the option of having the animation loop forever or only a specified number of times.
Figure 1b:(a, b) Screenshots show Beneton Movie GIF, a free application used to convert video files or image series into animated GIFs. (a) You can change playback speed by setting the delay between selected frames (type Ctrl-A first to select all frames). (b) When saving an animated GIF, you are given the option of having the animation loop forever or only a specified number of times.
Case reports are a type of radiology research literature. They belong to the class of descriptive studies.
The purpose of a radiology case report is to describe the patient history, clinical course, and imaging for a notable or unusual case. The case may be intended to aid other practitioners in interpretation, but frequently the oddity, rarity, and non-generalisibility of cases are meant more to amuse or entertain the reader.
A case report typically contains:
- a short introduction
- patient history and presentation
- a discussion of the imaging and other relevant interventions
- patient course
In radiology case reports, images from multiple imaging modalities are usually included, and gross pathology or histology is considered an excellent addition.
Case reports are generally considered the easiest and fastest radiology research paper to assemble.
Although debatable, the lack of "generalisibility" of case reports causes them to be regarded as lesser vehicles within research. Many journals will no longer accept case reports, for various reasons.
One disadvantage of case reports is that it may contribute to a type of recall bias in the reader. The attention the reader gives to a vanishingly rare case is held by the mind in a disproportionate regard compared with more common cases. The well-known maxim "an atypical presentation of a common disease is more likely than a typical presentation of a rare disease", is an effort to combat this type of bias.
Other disadvantages of case reports include:
- large numbers of case reports introduce an element of "noise" when searching the literature
- case reports claiming the first presentation of a case often find that they are actually not the first
- journals find that case reports do not get accessed as much as original research (it lowers their "impact factor")
That said, there are some advantages to case reports as well:
- the easier format allows junior researchers a chance to contribute to the literature, and helps them develop their skills
- a few case reports may develop into larger contributions to original research (for instance, in interventional radiology)
- they can be entertaining