Diagnostic Imaging Weekly Scan: Sept. 25, 2020

September 25, 2020

PET/MRI vs. PET/CT; Abdominal CT and COVID-19; Chest MRI vs Chest CT; Expert Interpretations of Endometriosis; and Delayed Breast Cancer Treatments for African American Women

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

Before we get to our featured interview this week with Dr. Anupam Basu about the disparities in lung cancer screening guidelines and how they are overlooking African American smokers at risk for developing the disease, here are the top stories of the week.

When it comes to detecting lesions, researchers from University Hospital Essen in Germany published a study this week that shows PET/MRI outperforms PET/CT even though the latter has long been considered the gold standard in oncology imaging and staging. According to their article, published in the Journal of Nuclear Medicine, the PET/MRI combination not only supports faster, more efficient use of local and whole-body staging in a single step, but it does so without exposing the patient to ionizing radiation. That makes it an ideal option for pediatric and adolescent patients. The team based their findings on 1,003 exams from 918 patients with a variety of cancers, including lung, gynecologic, breast, prostate, lymphoma, and several others. All patients underwent both PET/MRI and PET/CT, and based on the results, the team discovered PET/MRI found more lesions, finding additional information on 26.3 percent of scans not detected with PET/CT and changing treatment courses in 2.9 percent of cases. In addition, PET/MRI provided definite lesion classification in 11.1 percent more cases, promptings treatment changes in 0.5 percent of cases. But, perhaps, most importantly, the team said, PET/MRI reduced radiation exposure from 17.6 +/- 8.7 mSv with PET/CT down to 3.6 +/- 1.4 mSv – a 79.6-percent drop in dose.

More research surfaced this week that encourages radiologists to keep their eyes open for signs of COVID-19 outside the lungs. In a study published in the American Journal of Roentgenology, investigators from New York University Langone Medical Center added to the body of knowledge about how the virus manifests in abdominal scans. Based on their review of abdominal and pelvic scans, they discovered thromboembolic findings appear more frequently in COVID-19-positive patients than in those who do not have the virus. The team compared CT scans of a cohort of 82 COVID-19-positive patients and a group of 82 healthy adults, looking for thromboembolism and solid-organ infarction. They found 11 percent of patients who were positive for the virus had thromboembolic findings – four had thromboembolism, three had arterial thromboembolism in the aorta and major branches, and two had splenic infarctions of patent vasculature. In addition, they discovered that COVID-19-positive patients had elevated levels of inflammatory markets. Ultimately, they said, if you see these types of findings in abdominopelvic scans, ring the alarm bell.

And, even though chest MRI hasn’t been discussed as a first-line imaging modality during the pandemic, evidence is emerging that it can be an effective non-ionizing alternative for COVID-19- positive patients who need follow-up imaging, picking up both specific and indeterminate signs of viral infection just as well as CT. In the journal Clinical Imaging, a team from Iran examined chest CT and chest MRI scans conducted on the same day on eight COVID-19-positive patients who all had mild symptoms. The reviewing radiologist was able to identify ground-glass, consolidative, nodular or reticular opacities on both CT and MRI studies. Still, the team cautioned, using MRI presents challenges, such as accessibility and equipment disinfection concerns during the pandemic.

Outside COVID-19 investigations, an investigative team from Switzerland took a deeper look into who should be reading and interpreting MRI scans of suspected endometriosis. It’s a condition that affects between 6 percent and 10 percent of women, and these researchers found that radiologists who have expertise in women’s health imaging are really the ones who should been looking at these studies. As the use of MRI continues to grow because it provides a wider field-of-view for the provider, the team outlined in Academic Radiology that even radiologists with up to two years’ experience have a lower diagnostic performance when identifying this condition. For their study, they had four radiologists – a junior resident, senior resident, fellow, and expert – interpret pelvic MRI scans of 59 women with suspected endometriosis. They found differences in sensitivity, specificity, and area under the curve for all providers with experts performing significantly better. These findings have both clinical and educational implications, the team said – not only should referring providers send their endometriosis patients to radiologists with expertise in women’s imaging, but radiology training programs should also beef up the instruction their provide in this area.

Unfortunately, this week, there was more concerning news about African American women and breast cancer. In a study out of the University of North Carolina at Chapel Hill published in Cancer, women in this patient population are more likely to face treatment delays and longer treatment courses than their white counterparts, especially when they opt for radiation therapy. In a study of 2,841 women with Stage 1 to Stage 3 cancer, the researchers found that 13.4 percent of African American women experience delayed treatment compared to 7.9 percent of white women and they also had longer treatment times – 29.9 percent and 21.2 percent, respectively. Even among the higher socioeconomic group, African American women faced these problems more often – 11.7 percent versus 6.7 percent of white women. Most significantly, when these women added radiation therapy to surgery, they were 22 percent more likely to have delayed care compared to 1.6 percent who opted for chemotherapy and surgery.

And, finally, this week, Diagnostic Imaging spoke with Dr. Anupam Basu, a diagnostic radiologist with Cook County Health in Chicago, about his latest research published in the Journal of the American College of Radiology. Based on his investigations with colleagues at Northwestern University, the team determined that the current 30-pack-year threshold that primary care providers use to determine which patients should be referred for lung cancer screening is too high for African American smokers. Consequently, many are being overlooked when it comes to efforts that exist to find the disease earlier. He spoke with us about the details of his findings, what they mean for African American smokers, and how radiologists can use this information. Here’s what he had to say.

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