In normal practice, radiologists don’t get do-overs, which is why it’s imperative to get the diagnosis correct the first time. A recently published retrospective review of CT lung cancer screening images showed how cancers can be missed, and underscored the importance of advanced image processing techniques for early detection.

Dong Ming Xu, MD, and colleagues from the Department of Radiology at Mount Sinai School of Medicine in New York City, sought to understand reasons that a malignant nodule could be missed in the context of lung cancer screening, so they reviewed CT images of patients with lung cancer diagnosed in annual rounds of screening as part of the International Early Lung Cancer Action Program. They wanted to see if cancers discovered on annual repeat screenings could be spotted on a previous scan.

Results showed that of the 104 lung cancer patients in the study, 80 could have had their cancers identified on the previous screening.

While there are a number of reasons these cancers were not flagged for follow up, Xu and colleagues noted 21 patients with nodules larger than 3 mm that were similar in size to adjacent blood vessels.

“This finding suggests that use of computer-assisted diagnosis, which is particularly useful for separating nodules from blood vessels, would have led to even earlier diagnosis,” wrote the authors. “Perhaps in the future such visualization techniques will become an integral part of the reading process.”

Xu and colleagues pointed out that one-third of the patients with nodules masked by adjacent blood vessels saw their disease progress beyond stage I by their next screening.

Additional training in the varied appearance of malignant nodules could also be beneficial, but the results of this study seem to support the use of additional imaging display methods and the continued development of computer-assisted techniques. A patient’s early diagnosis may depend on it.

-Evan Godt
Editor – Health Imaging