Pathology in the Digital Era

Over the past decade, advances in digital imaging have transformed radiology departments by making it easier and faster for radiologic images to be shared among physicians via digital platforms, regardless of geographic location. Similar technology has advanced into the field of pathology, although the practice currently has limited approved application in the United States.

“Digital pathology is a generic term that refers to capturing microscopic images into a digital format,” said Thomas Bauer, MD, PhD, medical director for e-pathology in the department of pathology at the Cleveland Clinic in Ohio. Encompassed within digital pathology, he said, is the use of whole-slide imaging, which specifically refers to the use of high-resolution scanners to scan entire microscopic slides rather than isolated higher magnification fields.

Dr. Bauer and his colleagues have conducted a number of validation studies that successfully show that pathologists arrive at the same interpretation of an image whether it appears on a slide or is collected from a scan. These validation results were shown for routine pathology cases and difficult consultation cases, as well as when using frozen sections (Arch Pathol Lab Med. 2013;137:518-524; Arch Pathol Lab Med. 2014;138:1459-1465; J Pathol Inform. 2015;6:49).

Andrew B. Sholl, MD, director of autopsy pathology at Tulane University in New Orleans, called the benefits of digital pathology “quite extraordinary” and pointed out that the advantages of digital imaging over microscope slides include the ability of multiple pathologists to look at a case in real time and, at the same time, create a permanent digital record to allow for multiple reviews of the patient’s material. Additionally, he noted, the digitizing process allows for the ability to provide robust education for students and residents on difficult and unusual cases that may otherwise rarely be seen.

The drawbacks, he said, include the time it takes to digitize the images. “When scanning slides at 40x, it may take upward of 15 to 20 minutes per slide,” he said, which, he added, is not feasible for some cases, such as prostatectomy specimens that can range from 30 to more than 100 slides. “Another drawback is that the pathologist may feel uncomfortable that the provided image(s) do not portray enough data/histologic information to make a complete diagnosis,” he added.

Dr. Bauer also stressed that the time needed to interpret information from a scanned image is more than it would be from a microscope slide, particularly if used for primary diagnosis. “Pathologists have looked at microscope slides for a long time and we can do it relatively quickly,” he said. “The work stations we use to look at digital pathology images are not as fast as work stations in radiology, so the workflow of getting the patient information in front of us and the way you navigate between the images of each slide is not as efficient as it is for radiologists.”

Thomas Bauer, MD, PhDI think the most useful application right now and in the near future is to allow us to provide subspecialty expertise quickly for consultation diagnoses to pathologists anywhere in the world. —Thomas Bauer, MD, PhD

Current Use of Digital Pathology in the U.S.

Other than for education and research, digital pathology in the United States as approved by the U.S. Food and Drug Administration (FDA) is currently limited primarily to consultation cases, providing a second opinion for diagnostic cases that are difficult or ambiguous. For Dr. Bauer, that is the best application of this technology. “I think the most useful application right now and in the near future is to allow us to provide subspecialty expertise quickly for consultation diagnoses to pathologists anywhere in the world,” he said, adding that he and his colleagues routinely provide consultations to labs in China, Hawaii, Abu Dhabi, and Florida using digital pathology imaging.