Contents:
IntroductionBefore an image collection can serve as an educational tool, the student, researcher or health care practitioner must have access to it. Slide and photograph collections, which have been heavily used in fields such as radiology and pathology, are laden with access and management problems. These problems include both physical and intellectual access, the high cost of duplication and the inability to easily integrate and disseminate new materials.
The combination of digital image formats and networked computer environments provides the potential to overcome the traditional problems of medical image collections. This paper reports on medical image databases on the World Wide Web (WWW). An annotated list of Web sites containing medical images is also provided.
Physical and intellectual access
Both physical and intellectual access present problems to the users of image collections.
Photograph and slide collections are typically stored in a single area within the university. Storage may be at the medical department, or a more centralized location such as the medical library or learning resource center. In each of the cases the user and the collection must be physically brought together. This requirement severely restricts the user who may wish to study at home or at a location miles away from the collection. Additional restrictions are placed on the user if the image collection can only be accessed during limited operating hours or if the collection is in use by another person.
Once the user and the collection are brought together, intellectual access, that is retrieving the set of images relevant to the user's needs, presents another barrier. Browsing through large sets of photographs or trays of slides can be extremely time consuming. Even when cataloging is provided, it is often difficult to determine the usefulness of an image from a textual description.
Providing an image database on-line alleviates the problems of physical access. On-line image files can be viewed from computer terminals directly connected to the university network from anywhere on campus, from a remote connection at home or from anywhere else in the world. Connecting to the WWW with browsers such as Mosaic and Netscape allows for seamless downloading of image files. Furthermore, files can be available 24 hours a day, seven days a week and available simultaneously to many users.
Within the Web environment, intellectual access problems can be overcome by using combinations of search engines and thumbnail size images. For example, users could fill in a key word or string and retrieve a set of small images to browse. The set of small images can, in turn, be clicked to retrieve the document containing that image and its associated text. This strategy saves time by allowing the user to preview small, low resolution images prior to downloading large, high quality image files.
Deterioration of the collection and duplication costs
The quality of photographs and slides degrades over time and collections need to be replaced. Depending on the type of emulsion used, films turn brown, pink and may fade away altogether. Photographs and slides can also be easily damaged; a fingerprint or a drop of water can permanently ruin the image. Additionally, photos and slides can be lost and stolen.
Replacement and duplication of film collections is expensive. The cost of copying a 1000-case teaching file can be upwards of $10,000 for the film alone. A digital image can be duplicated swiftly and economically with a few simple keystrokes. The digital copy is an exact duplicate of the original with no loss of quality regardless of how many copies are made.
Inability to distribute collection updates
A well maintained teaching file should be dynamic with new cases added at regular intervals. Photograph and slide collections, however, become static entities as soon as they are distributed. Digital image files stored on a server have the power to be updated with ease. Changes that are made to a file are immediately available to the networked users.
In addition to overcoming the above problems, digital images on the WWW provide many distinct advantages over film-based collections. Digital images can easily be manipulated and enhanced. They can be saved at various sizes and resolutions, annotated and filtered. Global access to the teaching file can be bi-directional; contributions to the file can be transmitted over the network and incorporated into the file.
Problems related to Navigation
A common complaint regarding the WWW is the lack of indexing and the inability to find useful information. This criticism applies to medical image files on a macro and micro level.
On the broad, macro scale, wading through long lists and directories of potential sites can be time consuming. Search engines and directories may expedite the process but Web sites vary greatly in terms of content, quality and size, therefore users may need to explore several sites before finding an appropriate database of images.
On a micro level, navigating through a Web site may leave the user frustrated. Links within a Web site can be organized in a hierarchical arrangement, a flat arrangement or any permutation of the two. Indexes and tables of contents may not be logically arranged or may simply not be included. Terms chosen as links may be misleading or ambiguous and the user may follow several wrong paths before arriving at the desired destination.
Document boundaries present another navigational problem. Web sites can be comprised of any number of files. Well designed sites include consistent formatting and layout, graphics and metadata to maintain the look and feel of the parent document. When these cues are missing, it can be difficult to determine if there is a connection between documents or if a link has been followed outside of the initial Web site.
Another problem related to formatting is the over-use or inappropriate use of HTML tags. Poor design or ill attempts to enhance a document can obliterate the content and make the document difficult to use.
Problems related to Images
A further issue affecting the ease-of-use of medical image Web sites is related to the large size of image files. Good quality images are large in terms of transmission time across a network.
In designing Web sites, it necessary to consider the impact of how the images are incorporated into the document. Many sites do not include thumbnail versions of the image, thus forcing the user to wait for lengthy downloads before its value can be determined.
In any image database, the images themselves do not provide descriptive information. This becomes salient on the WWW because images can easily become detached from the textual portion of the document, as when images are copied and saved to a remote terminal. An advantage of digital images is the ability to attach annotations and watermarks onto an image. Watermarks create a digital signature which help to protect the owner of the image from copyright violations. At this time, attaching descriptive text and watermarks to medical images on the WWW is not standard practice.
Sophisticated image production has improved diagnostic procedures in many medical fields, such as radiology and cardiology. For example, physicians can view images of the brain with CT (computed tomography) and MRI (magnetic resonance imaging), and can observe organ physiology such as cardiac circulation with angiography.
The Web sites listed in the following section, Medical Image Sites on the Web, contain various types of medical images such as X-ray, PET and MRI. Brief descriptions are presented here to introduce the basic concept underlying each imaging modality. The descriptions are presented in order of increasing technical complexity.
This list of medical image Web sites illustrates a cross-section of what's out there and is not intended to be exhaustive. A well maintained, extensive list of internet medical resources produced by Gary Malet and Lee Hancock can be viewed at Medical Matrix. Pointers to more medical image sites can be found at Medical Images and Multimedia.
Images: X-ray, CT, MRI
Description:
Images: 3-D Reconstructions
Description:
Images: Line Drawing, X-ray, CT, MRI Description:
Images: X-ray, ECG, EKG
Description:
Images: MRI
Description:
Images: Photograph
Description:
Images: Microscope Slides
Description:
Images: Microscope Slides
Description:
Photograph and slide teaching collections present several access and management problems. The following list of problems applies to educational image collections in general, as well as to medical image teaching collections: Problem-Solving with Digitization and the WWW
This section addresses each of these problems and how they may be solved by using a digitized image collection available through the WWW.
In spite of the advantages discussed in the previous section, current use of medical image databases on the WWW is not flawless. Some of the problems are related to current limitations in technology, such as retrieving large image files via a slow modem connection. Other problems are related to the WWW in general, for example, the difficulty of finding good information among millions of documents. This section will explore some of the problems of using medical image teaching files on the WWW, specifically problems related to navigation and problems related to images.The Downside of On-line Image Files
Image file formats available for storing digital images include TIFF, GIF, JFIF, SPIFF, PICT, TGA, EPS, CGM, and Photoshop. GIF, TIFF, and JPEG formats are compatible with the World Wide Web. For an explanation of file formats, view Working with Images by Lee Liming or Graphics maintained by Martin Reddy.Image File Formats & Medical Image Modalities
Many fields of medicine have produced image databases for the internet. Fields that have traditionally been heavily image oriented, such as radiology and pathology are highly represented on the World Wide Web. Other medical disciplines represented on the WWW include dermatology, ophthalmology, pediatrics and more.Medical Image Sites on the Web
Go to:
Anatomy |
Cardiology |
Dermatology |
Hematology |
Nuclear Medicine |
Neurology |
Obstetrics & Gynecology |
Oncology |
Ophthalmology |
Pathology |
Pediatrics |
Pulmonology |
Radiology |
End of List
ANATOMY
URL: http://www.cc.emory.edu/ANATOMY/Radiology/Home.Page.MENU.HTML
Image File Format: GIF, JPEG
Thumbnails: No
Search Engine: No
Contains annotated images of body structures divided into four sections: Limbs, Head, Neck, Thorax, and Abdomen and Pelvis. GIFs are anchor images to larger JPEGs.
URL: http://www.vis.colostate.edu/library/gva/gva.html
Image File Format: GIF, JPEG, MPEG
Thumbnails: Yes
Search Engine: Yes
Contains "3D geometric database of the human body".
URL: http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/GA.html
Image File Format: GIF, JPEG
Thumbnails: No
Search Engine: No
Presents a course on "Structure of the Human Body." Learning modules are divided into regions including: Back, Upper Limb, Head and Neck, Thorax, Abdomen, Pelvis and Perineum, Lower Limb and Cross-sectional Anatomy. Each module presents objectives and key concepts. Tutorial and clinical cases are also included.
CARDIOLOGY
URL: http://www.med.umich.edu/lrc/cardiax/cardiax.html
Image File Format: GIF, MPEG
Thumbnails: No
Search Engine: No
"CARDIAX is a computer aided instructional package of 20 planned cases in basic cardiology. " This site includes a sample selection with Chest X-ray, Echocardiogram, EKG, Video Vignette and Heart Murmur.
URL: http://www-mri.uta.edu/cardiac/intro.html
Image File Format: GIF
Thumbnails: Yes
Search Engine: No
Publications and conference are exhibited with Power Point Slide presentations.
DERMATOLOGY
URL: http://www.uni-erlangen.de/docs/FAU/fakultaet/med/kli/derma/bilddb/db.htm
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: Yes
Contains approximately 800 dermatology images indexed by ICD-9 code.
HEMATOLOGY
URL: http://pathy.fujita-hu.ac.jp/~ichihasi/Pictures/atoras.html
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Contains microscope slides of hematology pathologies.
URL: http://www.hslib.washington.edu/education/blood/start.htm
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Contains hematology microscope slides with descriptions. Index can be viewed by thumbnail image index or by textual description.
Go to:
Anatomy |
Cardiology |
Dermatology |
Hematology |
Nuclear Medicine |
Neurology |
Obstetrics & Gynecology |
Oncology |
Ophthalmology |
Pathology |
Pediatrics |
Pulmonology |
Radiology |
End of List
Images: X-ray, MRI, Scintigraph
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
Nuclear medicine cases are presented with image findings, discussion and references. Cases are organized by diagnosis.
Images: Scintigraph
Image File Format: GIF
Thumbnails: No
Search Engine: Yes
Description:
Nuclear medicine cases are presented with diagnosis, very brief history and image. Cases are listed alphabetically by subject or may be searched with a form using controlled vocabulary.
Images: CT, MRI
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
Central nervous system images plus case histories. Includes Normal Brain, Cerebrovascular Disease, Neoplastic Disease, Degenerative Disease, Inflammatory and Infectious Disease sections.
Images: Ultrasound
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
Contains obstetric and gynecological ultrasound images with descriptive text. Sections include Normal first trimester findings, Normal second and third trimester findings, Abnormal first trimester findings, Abnormal fetal anatomy, Abnormal placenta and uterine findings
Images: Photograph, X-ray
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Description:
Contains a small set of radiation oncology images.
Images: Ultrasound, CT, MRI, Angiography
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
Includes sections on Diagnosis, Preoperative staging, Treatment and Follow-up of HCC with images and descriptive text.
Images: Photograph, Video
Image File Format: GIF, MPEG
Thumbnails: No
Search Engine: No
Description:
Includes interactive tutorial on Lens Removal, Phacoemulsification, and Wound Construction, currently under development. Contains lens placement and Peritomy MPEG movies.
Images: Angiogram, Photograph, X-ray
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Description:
"This site presents interesting cases from the Massachusetts Eye and Ear Infirmary's Grand
Rounds, as well as cases submitted from ophthalmologists from around the world." Cases are indexed chronologically and by diagnosis.
Images: Photograph
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
Includes images and text describing Macular Degeneration, Retinitis Pigmentosa, Glaucoma, Corneal Dystrophies and Retinal Detachments.
Images: Microscope Slides
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Description:
Contains two large volumes of images: Overview of General Pathology and Cardiovascular Pathology. Each image is presented as a thumbnail anchor with descriptive text. An alphabetical index is included.
Images: Microscope Slides
Image File Format: GIF
Thumbnails: No
Search Engine: No
Description:
A large collection of annotated pathology slides presented with the look of Power Point slides.
Images: Microscope Slides
Image File Format: JPEG
Thumbnails: No
Search Engine: No
Description:
Includes "more than 1700 archived images demonstrating
gross and microscopic pathologic findings associated with human disease states" plus descriptive text. Also includes tutorials in AIDS Pathology, Pathology of CNS Degenerative Diseases, Pathology of Diabetes Mellitus, Pathology of Drug Abuse, Pathology of Systemic Lupus Erythematosus, Pathology of Inflammatory Bowel Diseases and Pathology of Tuberculosis.
Images: Microscope Slides, X-ray
Image File Format: GIF
Thumbnails: Yes
Search Engine: Not Implemented Yet
Description:
Includes extensive case presentations of neonatal chest diseases.
Images: X-ray
Image File Format: JPEG
Thumbnails: No
Search Engine: No
Description:
Pediatric emergency room cases presented in two chronological volumes. History and discussion are included for each case.
Images: Photograph, CT, X-ray
Image File Format: GIF
Thumbnails: Yes
Search Engine: Yes
Description:
Includes sections on Pediatric Airway Disease, Lung Anatomy, Pulmonary Embolus, Diffuse Lung Disease with images, sounds and descriptive text.
Images: X-ray
Image File Format: GIF, JPEG
Thumbnails: Yes
Search Engine: No
Description:
Case presentations and images indexed by organ systems, Anatomic Area and Pathologic Diagnosis
Images: Ultrasound
Image File Format: GIF, JPEG, QuickTime
Thumbnails: No
Search Engine: No
Description:
Includes radiological images with sections on Liver, Pancreas, and Bile duct, Heart and Major vessels, Head and Kidney and Urinary tracts.
ConclusionReferences
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