US effective for working up masses found on DBT

By Kate Madden Yee, AuntMinnie.com staff writer

August 24, 2020 -- Ultrasound appears to be an effective and safe diagnostic workup modality when it comes to evaluating masses identified on screening digital breast tomosynthesis (DBT), according to research published in the European Journal of Radiology (EJR).

The findings suggest that, at least in the case of breast masses, it may not be necessary for women to undergo both digital mammography and ultrasound after screening DBT -- which has the benefit of reducing radiation exposure, wrote a group led by Dr. Jessica Porembka of the University of Texas Southwestern Medical Center in Dallas.

"DBT has been shown to be superior to conventional views in the diagnostic setting ... [and] women who already underwent screening DBT may be receiving unnecessary digital mammography prior to ultrasound imaging," the group wrote in an EJR article posted on August 5. "This potentially adds unnecessary complexity, cost, and radiation exposure, as well as prolonged diagnostic workup times without adding significant value."

Screening DBT reduces recalls compared with digital mammography alone, but still, sometimes follow-up is needed. Porembka and colleagues investigated whether in some of these cases --perhaps by type of lesion found on DBT -- women could undergo ultrasound alone rather than also having additional mammography.

The study included 266 noncalcified lesions in 247 women detected on screening DBT between January 2014 and December 2016. The lesions ranged from architectural distortions and asymmetries to focal asymmetries and masses. The investigators assessed the number and type of lesions that underwent diagnostic follow-up only with ultrasound.

The researchers found that ultrasound alone was used in 69% of workups of recalled masses, and that the odds of masses being worked up with ultrasound alone was eight times that of the odds of digital mammography and ultrasound being used. The authors also found that "ultrasound alone in the diagnostic evaluation of a mass seen on screening DBT had a higher yield of true lesions than masses worked up with digital mammography/ultrasound," confirming that "masses seen on screening DBT can be adequately evaluated with ultrasound alone."

However, ultrasound alone did less well with architectural distortions and focal asymmetries, with a detection rate of 44% and 25%, respectively, Porembka and colleagues cautioned.

"Our findings suggest that a combination of both [digital mammography and ultrasound] was preferred by radiologists in the work up of architectural distortions given the differential diagnosis of radial scar versus malignancy," the team noted. "For focal asymmetries, 68% were evaluated with digital mammography/ultrasound, while only 25% were evaluated with ultrasound alone, indicating that a combination of digital mammography/ultrasound is likely warranted in the work up of focal asymmetry on DBT."

In any case, the study results are good news for women undergoing diagnostic follow-up for masses found on screening DBT, according to the researchers.

"The implication of our findings is that we can save women unnecessary radiation and unnecessary cost of digital mammography by utilizing ultrasound alone in the evaluation of recalled masses," they concluded.

Transcranial U S helps solve COVID-19 mystery

By Theresa Pablos, AuntMinnie staff writer

August 21, 2020 -- Ultrasound scans with a robotic transcranial Doppler device provided a clue into why patients with COVID-19 experience severe hypoxemia without lung stiffness. In a serendipitous discovery, researchers linked the ultrasound findings to suspiciously low oxygen levels in patients with severe cases of COVID-19.

The researchers used a robotic transcranial Doppler (TCD) ultrasound system to assess cerebral blood flow in 18 patients with severe COVID-19 pneumonia. They had been looking for stroke and other cranial abnormalities, but they instead found that the majority of patients had detectable microbubbles, a finding that indicates abnormally dilated pulmonary blood vessels.

"This study helps explain the strange phenomenon seen in some COVID-19 patients known as 'happy hypoxia,' where oxygen levels are very low, but the patients do not appear to be in respiratory distress," stated senior author Dr. Hooman Poor, an assistant professor at the Icahn School of Medicine at Mount Sinai in a press release. Poor and colleagues published their research on August 6 as a letter in the American Journal of Respiratory and Critical Care Medicine.

In patients with classic acute respiratory distress syndrome (ARDS), pulmonary inflammation results in blood vessel changes that make the lungs stiff and impair oxygenation. But the amount of hypoxemia seen in patients with COVID-19 is often drastically out of proportion with lung stiffness.

The new pilot study revealed that vasodilation could help explain why COVID-19 pneumonia differs from classic ARDS. Using transcranial Doppler ultrasound scans, the researchers found that 83% of patients had detectable microbubbles. In addition, the number of microbubbles correlated with hypoxemia severity in patients with severe COVID-19.

In comparison, only about 26% of patients with classic ARDS show detectable microbubbles on transcranial Doppler scans. The number of microbubbles also did not correlate with hypoxemia severity for patients with classic ARDS.

"It is becoming more evident that the virus wreaks havoc on the pulmonary vasculature in a variety of ways," stated Poor.

The study included 18 patients with severe COVID-19 pneumonia who also had altered mental status and required mechanical ventilation. The patients underwent robotic transcranial Doppler ultrasound (Lucid Robotic System by NovaSignal) with an agitated saline solution.

The researchers injected the contrast agent in an upper extremity or through a central line in the internal jugular vein. NovaSignal's ultrasound software automatically counted the number of microbubbles detected over 20 seconds, and the researchers manually counted and confirmed the number of microbubbles as a precaution.

In healthy patients, the contrast microbubbles enter the lung blood vessels and get filtered out by pulmonary capillaries. If bubbles are detected in the brain, it indicates that the patient either has a hole in the heart or that the capillaries are abnormally dilated, which the researchers believe might be contributing to hypoxemia in patients with COVID-19.

Poor and his team at Mount Sinai are continuing their research and have thus far collected data from roughly 80 patients with various COVID-19 severity. The team plans to analyze microbubble transit, including how transit varies throughout the course of the disease.

"If these findings are confirmed in larger studies, pulmonary microbubble transit may potentially serve as a marker of disease severity or even a surrogate endpoint in therapeutic trials for COVID-19 pneumonia," Poor stated. "Future studies that investigate the use of pulmonary vascular constrictors in this patient population may be warranted."