Diagnostic Imaging's Weekly Scan: Feb. 15, 2021, to Feb. 19, 2021

Whitney J. Palmer

Mammography "Sweet Spot" Recall Rate; MRI for Early-Stage Testicular Cancer Follow-Up; COVID-19 and Body Self-Attack; Plus, Global Radiology

Welcome to Diagnostic Imaging’s Weekly Scan. I’m senior editor, Whitney Palmer.

Before we get to our featured interview with a multi-institutional panel about efforts to expand radiology education and the use of radiology technologies globally, here are the top stories of the week.

The “sweet spot” recall rate for screening mammography is actually lower than the currently accepted level, according to new research. Rather than the 12 percent-to-14 percent recognized, new research published in the American Journal of Roentgenology shows that the appropriate recall rate for 2D digital mammography and 3D tomosynthesis is 7 percent-to-9 percent. Following this new benchmark could potentially reduce the number of women who are called back for additional diagnostic imaging. To identify the optimal recall rate, the team examined nearly 1.1 million 2D and 3D exams from women between the ages of 40 and 79 from January 2005 until December 2017. Based on their evaluation, they identified an overall mean recall rate for mammography of 10.7 percent and a cancer detection rate of 4 per 1,000 studies. The biopsy recommendation rate was 1.6 percent. When they drilled down, though, they discovered that 2D analog exams had the highest recall rate at 11.2 percent, followed by 2D digital exams at 10.8 percent and 3D tomosynthesis at 9.4 percent. 3D tomosynthesis also had the highest mean biopsy recommendation rate at 1.93 percent, followed by 2D digital and 2D analog exams at 1.55 percent and 1.47 percent, respectively. These results, they said, showed that a recall rate of 7 percent-to-9 percent maximized cancer detection and minimized unnecessary biopsy.

Using MRI, instead of CT, for follow-up in men who have been treated for early-stage testicular cancer reduces their exposure to additional radiation and could lower their risk of developing future cancers. Currently, treatment for these men involves removing the affected testicle and following the patient with CT for five years. However, new research presented at the GU ASCO conference this month shows that MRI performs just as well at detecting any cancer relapse without the extra exposure. Investigators reached this conclusion by testing three follow-up protocols – the standard seven CT scans, three CT scans, and the same regimens with MRI – with 669 men with stage-one testicular cancer who had their affected testicle removed. Only 12 percent of the men had a relapse, 10 of which were advanced disease at detection. Of the cancers, nine were detected in the three-scan group, and only one was picked up in the seven-scan group, indicating that any additional CT scans after three years are unnecessary. CT detected eight cancers while MRI identified two – this difference, however, was not significant, the team noted.

Sore muscles, achy joints, and swollen toes – it’s not what we typically think of when we talk about COVID-19. But, these symptoms are proof that the virus does not only attack the body – it pushes the body to attack itself. In a study released this week in Skeletal Radiology, investigators revealed that CT, MRI and ultrasound scans show evidence of how the virus can kick-start rheumatological issues in some patients. By examining scans from patients who presented between May 2020 and December 2020, the team pinpointed several causes of these musculoskeletal symptoms, including edema, inflammation, hematomas, and gangrene. In addition, some images revealed blood clots or nerves that were bright and enlarged, indicating injury. If radiologists know to look for these findings, they can better identify patients who might benefit from a referral to a rheumatologist or a dermatologist for more extensive treatment, the team said.

And, finally, this week, Diagnostic Imaging spoke with several of the radiologists from Penn Medicine (Abass Noor, M.D.), the Children’s Hospital of Philadelphia (Kassa Darge, M.D.), the University of Texas Southwestern (Ajay Kohli, M.D.), and the University of California at San Francisco (Bhavya Rehani, M.D.) who are currently involved in efforts to expand radiology education and technologies to resource-limited areas globally. They discussed the importance of these efforts, what has been accomplished to date, and what the future holds. Here’s what they shared.

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