Medical scan mistakes: what's behind the problems?

Problems with medical scans — such as missed cancers and misdiagnoses — stem from technology changing faster than radiologists training can handle, but some health authorities are trying put in a system to double check scans.

Radiologists to put in more checks to address concerns

As John Moser's health slowly deteriorated in 2010, he began to suspect he might be battling cancer.

His daughter, Janet Baird, told him that he couldn't be — a scan in Powell River, B.C., in August that year revealed nothing to be concerned about.

"We told him, 'It's not cancer, they checked,'" Baird told CBC News. 

But a scan before Christmas that year showed cancer so widespread through Moser's body that his case was terminal.  Baird says the doctors told her family to take him home, and prepare for the worst.

The news devastated her. Her father was suffering and their family knew he was nearing the end, but if they had known he had cancer perhaps they could have made him more comfortable, Baird said. 

She also felt terrible that the family didn't listen to her father at the time he needed them most.

"It was really horrible. I feel like we kind of failed him," Baird said. "But we didn't know."

Moser died in January 2011. Later, the radiologist who conducted Moser's scans and three other radiologists would become the focus of an investigation by B.C. health authorities. A review by the B.C. Patient Safety and Quality Council eventually showed that these four radiologists were not qualified to read the scans they were interpreting.

Issues found in at least 5 provinces

A similar problem surfaced in Quebec just a couple of weeks ago, when a review of thousands of mammograms flagged for possible errors found 109 breast cancers that were missedNewfoundlandSaskatchewan and Alberta have also faced problems with potential misinterpretations of medical scans.

It's a recurring issue that has left some Canadians, such as Baird, worried about the reliability of medical scans.

James Fraser, the president of the Canadian Association of Radiologists, says there are many efforts in place, both provincially and nationally, to add more checks and balances to try to catch mistakes before they happen.

"Right now with what's going on, it's really the focus of our work right now to get all of these in place to make sure that Canadian radiologists are providing the utmost safety and quality to our patients," he said.

Changing technology part of problem

Doug Cochrane, the chair of the B.C. Patient Safety and Quality Council, said medical imaging has always been an inexact science, but part of the problem stems from rapid advances in diagnostic imaging technology in the last decade.

Physicians say that improvements in medical scanning technology have progressed so rapidly that it is difficult for radiologists to keep up without additional training. (Mike Groll/File/Associated Press)

Years ago, radiologists would typically use a single-slice CT scanner, which could produce one scan a minute, he said. Now, with new technology, doctors can retrieve hundreds of high-resolution images in the same amount of time, he added.

Not only is there more data, analyzing these scans is not as simple as applying the same principles used with previous technology, Cochrane said. Now, radiologists can see structures and physiological processes that could never have been seen before, in detail. Interpreting this wealth of information is difficult without specialized training, he added.

"The technology in some ways has outstripped our ability to learn on the job … This is really an issue of mature people, old people like myself, trying to keep up," he said.

Scans on record increase scrutiny

Fraser says another factor is the plethora of scans and images on record which make it easy to scrutinize the work of doctors after the fact.

"The main factor here is there are very few medical specialties or practices in medicine where there is this kind of scrutiny available," he told CBC News. "In our field, the images are archived onto computers and our reports are put next to them, and it's a permanent record. It's very easy to go back and agree or disagree."

Other fields of medicine do not have that luxury, said Patrice Bret, chair of medical imaging at the University of Toronto.

"If you have surgery, you don't have a video camera recording of the procedure … you don't have a black box like in a plane. In radiology, you have that … That's why you see this explosion now of things [happening] more in radiology than in other specialties."

Still, Fraser says the bulk of the problems involving misdiagnoses and misinterpretations of scans usually involve radiologists in a rural setting, without much support, or older radiologists.

Incidents not isolated: Quebec lawyer

But Jean-François Leroux, whose Montreal law firm represents nine women considering or already taking legal action against a Quebec radiologist who missed dozens of breast cancers, says these were not isolated incidents.

"It was really the absence of any control of the quality of the procedures," he said.

To try and detect problems before they impact patients, many health authorities are looking at closing the gap.

The Quebec College of Physicians has recommended better oversight of radiologists, digitized mammograms to make them easier for others to consult and more uniform standards for private clinics.

Another option in the works is a peer-review system, where a percentage of the scans conducted are reviewed by another radiologist.

B.C. is looking at setting up a program where about three to five per cent of radiology scans would be examined by a fellow radiologist to avoid mistakes, Cochrane says.

This peer review would take place within three or four working days after the scan, he said. If there are inconsistencies, the College of Physicians and Surgeons and the B.C. health authorities would be responsible for making sure the radiologist's skills are up to par, or directing him or her towards a different career, he said.

Portion of scans to be reviewed

B.C. is also trying to establish a system where radiologists can request a test of their skills, to see if there are shortfalls.

"[These systems] will help the public be assured that the process that they think is there has some rigour and has some teeth," Cochrane said. "And that's part of trying to rebuild the face of the system. For some, we may not be able to rebuild. But for some we will be able to, and provide a reliable and stable system for them."

They aim to have the system implemented provincewide by August of this year, he said.

But Baird says that all scans should be examined twice, not just a percentage, to avoid cases like her father's slipping through the cracks.

"I think every single one should have two eyes looking at it," she says.

Bret said while this would be ideal, it would be very costly and lengthen the already long waiting lists for medical scans.

"If we suddenly double the work of radiologists, we will have to double the work of each radiologist or double the number of radiologists. There is a cost," he said.

Faith in system 'destroyed'

Also, being overly suspicious can be detrimental as well, calling for too many invasive tests and biopsies, he said.

Overall, Bret says he believes the vast majority of radiology practices are "very safe."

"What we need to do is to provide now an accountability process ... The patients need that," he said.

Although these systems, once in place, will improve things, Baird won't be letting her guard down anytime soon.

"If I were to get really ill, it would be like a dice tossed," she said. "Would they catch it? Would I get into a hospital? ... It has destroyed any faith in any kind of system."