Digital Imaging in Pathology

The field of pathology is adopting digital imaging technology. Newer versions of laboratory information systems and anatomic pathology information systems include image capture modules that allow digital pathology images - captured by the digital camera on a microscope - to be appended to patient reports. Early adopters revere digital pathology imaging as a means to gather additional information for clinicians and patients and benefit long-term care. They also talk about the day when pathology images will be integrated into electronic medical records. On the other hand, pathologists resistant to changing their slide-centered world are not yet convinced that these digital images are a necessity in the field.

"There is not a pathology department that does not operate without a laboratory information system [LIS]," says Bruce Friedman, MD, professor of pathology at the University of Michigan Medical School. The LIS and APIS (anatomic pathology information system) acquires numerical and textual information generated in anatomic and clinical pathology, stores it and makes it available to clinicians. Some systems offer image capture modules that allow pathologists to integrate laboratory images into final patient reports. 

Using a high-end digital camera attached to a microscope, pathologists capture static images of small biopsies, tumors and skin biopsies. The images, typically in JPEG format, are appended to the report that is distributed to clinicians, specialists and referring physicians. As informatics continues to play a role in advancing the field of pathology, these images may one day be incorporated into electronic medical records (EMRs).

Is there a need to integrate pathology images into reports and EMRs? It can improve the clarity of communication between pathologists and clinicians, reduce errors and provide medico-legal documentation, says Mark Tuthill, MD, division head, pathology informatics, Henry Ford Health System. "Cost is another benefit: we have to take pictures in pathology for documentation purposes. Digital imaging is superior to traditional film-based photography for several reasons, including cost."

Some pathologists question its clinical relevance, arguing that clinicians, interested in textual information do not need to look at images. From a workflow perspective, pathologists must take extra time to capture representative images that buttress the diagnosis, and this may be seen as a hindrance.

Another piece of information

An image is an important part of a pathology report in complex cases, says Friedman. "Image capture, storage, retrieval and integration into the pathology report and EMR is very important. A digital image can only add to the report," he says.

At Sacred Heart Hospital in Allentown, Pa., pathologists use Psyche Systems' Window Path APIS and its image management module to permit the integration of JPEG pathology images into reports. "I can demonstrate to the physicians who sent the biopsies as to what I am talking about in my diagnosis and why I am calling something malignant or not," says James Chiadis, MD, a pathologist at the hospital. "I can integrate either [digital] microscopic slide images or gross photographs and include that in a report to show to the physician, or even the patient, if he or she so desires."

There are probably two main reasons that the field is interested in incorporating pathology images into reports, says Walter Henricks, MD, director of laboratory information services and a surgical pathologist at the Cleveland Clinic Foundation. "The first of these is primarily a response to market demands. Pathology labs have heard from the referring physician clients that they like to see images in reports.

"The other driver, which is related, is that some clinicians indicate that they consider the images useful for patient education and communication," continues Henricks "Many sites and pathology groups that are capturing images are using them for educational, quality assurance, and or documentation purposes."

At Duke University Medical Center, surgical pathology as well as laboratory information constitutes two thirds of a patient's EMR. Pathology images are not integrated with EMRs; nor are they appended to reports. However, digital gross specimen images and microscopic images are captured for research, teaching and illustration purposes. "We are in the process of looking at an upgrade to our LIS and one of the key features we are looking for is support for images for the pathology report, which will be transmissible to the EMR," says John Madden, MD, PhD, associate professor of pathology at Duke.

In addition to making the pathology report more attractive and more engaging for physicians, incorporating images is important for documentation purposes. "If it's a diagnosis of cancer, the picture provides a medical legal record of the field upon which the diagnosis was based. Particularly in small biopsies, I think many pathologists feel better actually having the picture electronically stored within the system together with the report," explains Madden.

Information at your fingertips

Entering the informatics realm, the pathology department at the University of Virginia Health System in Charlottesville digitizes selected fields within a pathology slide to create an annotated image. "A dermatopathologist with a skin biopsy will slice and dice it and put it under the microscope to decide whether it's a benign condition or something a little more invasive," says Robin Felder, PhD, professor of pathology and director of the Medical Automation Research Center. "A [digital] picture can be captured and shared with other pathologists within the institution."

As the technology evolves, Felder says the pathology department's ultimate goal is to be able to quickly attach images to the EMR so that clinicians spend less time carrying glass slides around the building. "Because that is what the current system is - a sneaker net of slides."

EMRs are longitudinal records of patient information, and images will only add to the value. "When a patient is seen 20 years hence and has a reoccurring lesion in the lung, very quickly we can see whether it's the same lesion or a different lesion by referring to the images in the EMR," explains Michigan's Friedman. "But there is also this notion now that you have a more complete record for clinical care delivery and also for research. For research, not only do we have a clinical record of patients with observations and vital signs, but we have an accurate representation of the lesion."

The whole is greater than its parts

Some pathologists are on the fence as to the need for taking digital pictures of pathology slides for inclusion in final reports. Those who are more resistant to the technology may be waiting for improvements in virtual slide technology. Also called digital microscopy systems, the technology lets pathologists digitize an entire pathology slide, rather than just capture a single representation of the slide. The digital image can be uploaded to a computer for processing, manipulation and review. Each image will be archived as an original file and pathologists will not have to store glass slides.

"Pathology images typically require a pathologist to interpret them, so they do not have the same value once distributed as say a chest x-ray that any doctor should be able to make a basic interpretation on," says Henry Ford's Tuthill. "To date, the words have said it all for the pathologist and the picture may have little meaning to the unskilled. That said, many clinical providers desire to see their patients pathology, and this has long been a key component of quality laboratory diagnosis that allows for education and exchange for information.

"Digital images in reports can make up for some of this lost communication since doctors now practice in geographically separate areas," continues Tuthill. "Technical barriers and limitations to digital imaging as applied to pathology have also kept this process slow. Up until now, images had to be made by digitally photographing fields of view, saving them, and attaching a few selected images to a case. This is inefficient and may not represent the case overall. Now, we can digitize the entire glass slide - effectively allowing one to use a virtual microscope to browse the image at different magnifications and locations on the slide."

Henricks agrees that the future of pathology lies in digital microscopy. "In the future, whole slide digitization technology and virtual microscopy tools promise to make the use of digital imaging in pathology more central to the practice," says Henricks. "In these technologies, entire glass slides are scanned to create digital slides, which in conjunction with virtual microscopy tools allow for field selection, magnification selection, and depth of focus that mimics traditional microscopy. As these tools mature, adoption of digital imaging may become more widespread in pathology."


Mayo's Electron Microscope Lab pioneers digital imaging

The Electron Microscopy Core Facility at the Mayo Clinic in Rochester, Minn., has been involved in digital imaging since 1997. Capturing approximately 70,000 electronic images annually, Jon Charlesworth, manager of the laboratory, says nearly 90 percent of clinical diagnostic cases are renal biopsies, tumors and storage diseases. Just about anything is looked at on the research side, explains Charlesworth, including virus particles, cells grown in culture, tissues from various animal models, purified protein molecules as well as nonbiological samples such as stents, polymers and prosthesis devices.

"Pathologists give us a biopsy or an autopsy sample," says Charlesworth. "We cut very thin slices of the sample and place that on a small grid that goes into the electron microscopes. We evaluate the samples looking for particular indicators of various diseases. We capture representative digital images [although we do produce film for some of our clients] and save them on a server. A pathologist who has access to the clinical sample can log into the server and can copy the folders to his or her desktop or review them at their leisure.

"If the case is from a patient from outside Mayo [sent through Mayo Medical labs], then we create a CD with the annotated images and send it with the report to the requesting physician," continues Charlesworth. "If the case is a Mayo patient, then the images are reviewed by the Mayo pathologist and noted on the pathology report that electron microscopy was performed and either confirm or contradict the suspected diagnosis. Images in these cases are generally not included on the patient report. If another Mayo clinician would like to review the images for that case, he or she would contact our laboratory and we would place the images on a server that he or she could access. We convert the original images to tif images for the cases on CD, but Mayo pathologists receive images in their original format. These original images are 1 to 5 MB in size."


Pathologists 'Reach' Out and Touch Patients Around the Globe

"From the Armed Forces Institute of Pathology (AFIP) located in Washington, D.C., we control microscopes located elsewhere in the world," says Bruce Williams, MD, chairman of the department of telemedicine at AFIP. "We currently have 27 scopes installed at Army hospitals around the world - a majority of these are in the United States, but we also have scopes located in Baghdad, Seoul, Germany and Honolulu."

The technology, called robotic microscopy, permits Washington-based pathologists to provide immediate diagnostic assistance and consultation via telepathology to pathologists in Baghdad, for example, for a soldier reporting a rapidly growing pigmented lesion on his arm. Quickly ruling out melanoma, the soldier avoids an emergency Medivac and doctors can proceed with local treatment. "These are the kinds of things that allow the AFIP to transcend time and space and to impact patient care just about in real time" says Williams. Pathologists worldwide - at both civilian- and military-based medical facilities - can use AFIP's services for help on difficult cases.
AFIP's telemedicine program, which began in 1993, started with static image telepathology in which a high-resolution digital camera is mounted on a microscope. A local area network connection is used by a remote pathologist to send static images (saved in standard format) to AFIP headquarters. Until 1999, that was pretty much standard, says Williams, but AFIP pathologists could be at a disadvantages because they had only a fraction of the entire slide at their disposal and the captured image was highly subjective. Follow-up material was needed on most cases.

With the Army's ample investment of more than $2 million in robotic microscopy technology, Williams says this advanced form of telepathology now constitutes 70 percent of his department's cases.

Williams forsees whole slide technology - where an entire pathology slide is digitized - as AFIP's future realm. "Virtual slide technology has been with us since about 1997, but it is currently used for education and research," says Williams. "These machines are not yet FDA-approved for diagnostic applications. Virtual slides, being a precise digital replica of the scanned slide, can be infinitely reproduced, transported to remote consultants in seconds, and never get lost or broken.

"The AFIP has about 2,500 virtual slides being saved on its web servers," continues Williams. "We are the only site where a pathologist can see a virtual slide of SARS (severe acute respiratory syndrome) or monkeypox. We can make a slide of these very rare diseases and make them available to any pathologist in the world. In terms of research, we are using [this technology with a range of academic institutions and other government facilities]. It's a great way for people located around the world to be able to look at the same slides at the same time as us and reach a diagnosis."