Valerie Neff Newitt
December 2018—Quality in histology is at the heart of successful whole slide imaging, and a new program that rolls out in January will provide laboratories the aid they may need as they bring whole slide imaging on board.
The CAP/NSH Whole Slide Image Quality Improvement Program is intended for laboratories that have the ability to perform whole slide image scans and want those scans to be assessed externally. Enrollment is underway now.
“If you have a bad H&E-stained slide, you will get an even worse digital slide. You need good H&E preparation and techniques to get
a good scanned slide. Not everyone understands that adequately,” says Humberto Trejo Bittar, MD, assistant professor of pathology, Division of Anatomic Pathology, University of Pittsburgh Medical Center Presbyterian Hospital.
Some laboratories may think they can stick with old specimen and slide preparation practices and habits, he says. “They do not think they need to incorporate anything new. Well, think again,” advises Dr. Trejo Bittar, a member of the CAP/NSH Histotechnology Committee.
“There are several characteristics that an H&E slide must have to be a good scanned slide,” he says. The new program, a collaboration of the CAP/NSH Histotechnology and CAP Digital Pathology committees, “will help labs understand that.”
The Whole Slide Image Quality Improvement Program will begin with two mailings to participants, six months apart. The “A” mailing will be distributed Jan. 22. Laboratories will be instructed to stain with H&E tissue from a breast resection, lung resection, breast needle core biopsy, and prostate needle core biopsy. “For each, they will create a slide, stain with H&E, and make a scan. Then they will upload their scan to a wonderful tool called DigitalScope,” says Histotechnology Committee member Robert Lott, BS, HTL(ASCP), external quality assessment manager, Roche Tissue Diagnostics. DigitalScope is the CAP platform that allows the user to pull up a digital image, focus up and down on it, and move it five, 10, 20, or 40×, “just like on a microscope,” Lott says, adding, “All details can be seen.”
Labs will be instructed in how to package their glass slides and send them to the CAP.
In July participants will receive the “B” mailing with instructions for tissue from a colon resection, kidney resection, colon biopsy, and skin punch biopsy.
Group A scans will be graded in April 2019, group B scans in September. Pathologists and histotechnologists who have been approved to grade will perform the assessments using a numeric scale. “They will be pathologists from the CAP Digital Pathology Committee as well as individuals experienced in digital pathology from the CAP’s Histotechnology Committee,” says Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC, manager of Premier Laboratory, LLC, Longmont, Colo., and a member of the Histotechnology Committee. All graders will undergo an extensive orientation. “They will learn the different scoring criteria so that everyone is on the same page with respect to how they score the scans,” Chlipala says.
Subscribers will be able to access DigitalScope and see their scans and the quality-related issues the graders may have found, Chlipala says. “The grading committee will be able to put annotations on the images and point out specifics: ‘Here’s where a sectioning artifact is causing the image not to be in focus,’” for example, or “‘There is a fold, or holes or bubbles, in the tissue and it is causing the scan to go out of focus in certain areas.’” Participants can view their scans and see in real time where a problem exists. “I think that is a great learning tool,” she says. “Labs can see what the graders are seeing and are concerned about. They can see why they’ve been graded off for a particular parameter.” It is that connection between written criteria and a viewable image, Chlipala says, that will allow participants to say, “‘Now I understand why it is important that our histology quality is good.’”
Lott says laboratories will see the benefits of enrolling because the program is not just about scanning. “We will be using participants’ digital images to evaluate if they are of diagnostic quality, but we will also provide feedback on the quality of their tissue preparations. Since we will have both their glass slides and digital scans, we will be able to compare the two.”
Chlipala agrees that not all laboratories fully understand the extreme dependency of digital imaging on histology. “You must have proper scanning procedures in place, yes, but that’s not the whole picture. The quality of the histology preparations is integral to the success of implementing a WSI solution.” What makes for an acceptable glass slide in the lab, she says, does not necessarily translate to a successful digital scan. “As an early adopter of digital technology, I am aware of that fact, but I don’t think most people are.”
Lott says while pathologists have learned to work through, and interpret in spite of, the artifacts in a glass slide, those same defects can affect the quality of a scan. “If the tissue section is uneven or if there are scratches or other kinds of artifacts in the original preparation, the quality of the scan suffers and may affect its use for diagnosis. Pathologists can fine focus on a microscope and have wiggle room to work through artifacts present in some samples. But they won’t have that option with whole slide imaging because they lose the ability to fine focus.”
The cutting, staining, and placement of a sample on a slide all affect a digital scan. “For example,” Lott says, “if a tissue section laps over the edge of a slide, the scanner can’t detect that piece of tissue. There may be important diagnostic information in that little piece lapping over. If you inadvertently cut off a piece of tissue, the scan is incomplete and virtually useless to the pathologist.” How these issues affect the scanning will be part of the educational component of the program. “Labs will get a technical assessment of the quality of their images and their histology, and an assessment of whether the product they submit is of diagnostic quality.”
“Part of the beauty of the program,” Dr. Trejo Bittar says, “is that when we send grading results to subscribers, we will troubleshoot problems and tell them how to fix errors.”The new program is part of the CAP HQIP menu in the anatomic pathology section of the 2019 CAP catalog. As the program continues to improve the quality of digital slides, committee members are hopeful it will have an impact on the international community. Laboratories in some countries face barriers in sending glass slides to the CAP, and those that do cannot participate in HQIP programs. “This program can be the building block for subsequent programs for quality assessment using digital equipment,” Dr. Trejo Bittar says. Instead of having to send glass slides, labs will be able to send digital slides. “This will be especially important to our international subscribers who have restrictions on what they can and cannot send out of their countries. In the near future, they may be able to send us digital slides and we can provide them with the same assessment we give to subscribers who provide glass slides. This will further extend the reach of CAP to worldwide HQIP subscribers.”
The Histotechnology Committee, chaired by Mansoor Nasim, MD, PhD, and the Digital Pathology Committee, led by Andrew Evans, MD, PhD, had begun to create this program before the Food and Drug Administration approved last year the Philips IntelliSite Pathology Solution for primary diagnosis. “The Philips FDA approval lit a fire under our efforts. It was great timing,” Lott says. “However, it was not the driving force. We had already started before the approval was granted.” He credits the program to the groups having a “proactive vision of the future and anticipating a need.” Dr. Trejo Bittar, who says they wanted to be “in the beginning of the wave, not at the end,” predicts whole slide imaging will be the norm in five to 10 years.
Ensuring the quality of histology and whole slide image scans is important not only for primary diagnosis, Dr. Trejo Bittar says, but also for research, teaching, and remote consultation. “The new program provides to pathologists peace of mind that their labs are making whole slide digital images that truly represent glass slides. It will help labs and all scanning facilities to have the expertise they need to produce slides that pathologists will feel comfortable reading. And ultimately this may encourage those pathologists doing only research with digital scans to say, ‘Okay, I am getting better, our scanning people are getting better, our slides are looking better. Now we can consider moving forward to the next level of use, primary diagnosis.’”
Valerie Neff Newitt is a writer in Audubon, Pa. The program price is $550. To enroll, call the CAP at 800-323-4040 option 1 or (outside the U.S.) at 847-832-7000 option 1. Or enroll at www.cap.org (click on Shop tab) or send an email to firstname.lastname@example.org.