US can be used for patients with COVID-19.

By Theresa Pablos, AuntMinnie staff writer

March 19, 2020 -- Ultrasound scans show promise for helping to monitor patients with COVID-19, according to a letter published on March 12 in Intensive Care Medicine. The researchers used lung ultrasonography to monitor more than a dozen patients in China with COVID-19 infections.

Because of its high sensitivity, CT is currently the imaging method of choice to diagnose and monitor patients with COVID-19. However, chest CT may also present difficulties for patients with hypoxemia and hemodynamic failure, and the enclosed environment may contribute to the spread of the coronavirus.

In the research letter, the authors found lung ultrasonography could overcome some of CT's limitations. Ultrasound may even be the better imaging choice for patients in critical condition who cannot be easily moved.

"Based upon our experience, we consider that lung ultrasonography has major utility for management of COVID-19 with respiratory involvement due to its safety, repeatability, absence of radiation, low cost, and point of care use," wrote the authors, led by Qian-Yi Peng, from the critical care department at Xiangya Hospital in Changsha, China.

COVID-19 on lung ultrasound scans

Peng and colleagues performed lung ultrasonography on 20 patients with COVID-19. They used a 12-zone examination method, which resulted in the following five characteristic findings:

1. Pleural line thickening and irregularity
2. Variety of B-line patterns, including focal, multifocal, and confluent
3. Variety of consolidation patterns, including multifocal small, nontranslobar, and translobar with occasional mobile air bronchograms
4. Visible A-lines during the recovery phase
5. Rare occurrence of pleural effusions

"The observed patterns occurred across a continuum from mild alveolar interstitial pattern, to severe bilateral interstitial pattern, to lung consolidation," the authors wrote.

Above: A CT scan and ultrasound scan from one patient with COVID-19. Below: A CT scan and ultrasound scan from a second patient with COVID-19. All images published in SSRN and courtesy of Yi Huang and colleagues.

During the early stages of COVID-19, patients tended to exhibit focal B-line patterns, followed by alveolar interstitial syndrome as the disease progressed. In patients who were critically ill, ultrasound scans showed A-line patterns in the convalescence. For patients with pulmonary fibrosis, the scans found pleural line thickening with uneven B-line patterns.

"The findings of lung ultrasonography features of [COVID-19] are related to the stage of disease, the severity of lung injury, and comorbidities," the authors wrote. "The predominant pattern is of varying degrees of interstitial syndrome and alveolar consolidation, the degree of which is correlated with the severity of the lung injury."

The findings from Peng and colleagues mirror those of a previous study published on February 28 in SSRN. In the earlier study, lead author Yi Huang and colleagues used ultrasound scans for 20 patients with COVID-19 at the Xi'an Chest Hospital in Xi'an, China.

Huang and colleagues also used the 12-zone examination method and found similar ultrasound scan characteristics to Peng and colleagues. For instance, they found a higher proportion of B-line patterns in lesion areas, including fused B lines, as well as pleural lines that presented as discontinuous, interrupted, or unsmooth.

Better than CT?

The ultrasound scan findings from both studies lined up well with chest CT scans results. For instance, in Peng and colleague's study thickened pleura on CT scans presented as a thickened pleural line on ultrasound. Further, pulmonary infiltrating shadow on CT was linked to confluent B-line patterns on ultrasound.

Similarly, the chest CT scan of one patient in Huang and colleague's study showed ground-glass opacity and air bronchogram sign under the pleura of one lung (Figure 1). The ultrasound scan of the same patient revealed an uneven pleural line and B-line patterns (Figure 2).

While both sets of authors agreed that lung ultrasonography had several benefits over chest CT for patients with COVID-19, they also noted ultrasound shouldn't be used as the only imaging method. For instance, CT is still needed to identify patients who have pneumonia that does not extend to the pleural cavity,

• "Our study indicated that ultrasound can show typical manifestations and has advantages over CT in the clinical diagnosis and treatment of noncritical COVID-19, but it cannot replace CT," wrote Huang and colleagues. "Ultrasound can be used as a supplemental method."

What US scoring system works best in diabetes?

By Theresa Pablos, AuntMinnie staff writer

March 18, 2020 -- Only one technique to assess medial arterial calcification (MAC) from an ultrasound scan can also predict related cardiovascular and diabetes complications, according to a study published on March 6 in Ultrasound in Medicine and Biology.

The authors evaluated two methods for diagnosing MAC severity:

1. The presence of MAC in three unique artery segments
2. The length of MAC in centimeters

Only MAC identified through the segmentation method was able to independently predict whether a patient would also experience peripheral artery disease and diabetic nephropathy, the authors noted. However, both methods for calculating MAC from ultrasound scans were still valuable.

"Consistent with previous studies, the presence and severity of MAC were associated with diabetic complications in our univariate analysis, regardless of whether the length or segmentation method was used," wrote the authors, led by Jing Tian from Sun Yat-Sen Memorial Hospital in Guangzhou, China.

Ultrasound is one tool that can be used to help screen patients with diabetes for MAC, but there is no consensus on the best scoring method to evaluate MAC severity from ultrasound scans. Therefore, the authors compared two commonly used scoring systems: the segmentation method and the length method.

In the length method, MAC severity is determined based on the severity of calcification in a 4-cm scanned area. A MAC length of 0 cm, less than 1 cm, 1 to 2 cm, 2 to 3 cm, and greater than 3 cm on ultrasound scans correspond to MAC scores of 0, 1, 2, 3, and 4, respectively. The scores are then added up, with higher scores indicating higher MAC severity.

In the segmentation method, a point is given for the presence of any MAC in the superficial femoral artery to popliteal artery segment, the anterior tibial artery to dorsalis pedis artery segment, and the posterior tibial artery and peroneal artery segment. Like in the length method, the scores are added up, and higher scores indicate higher MAC severity.

The researchers used both MAC scoring methods on 359 patients with type 2 diabetes who stayed at a hospital endocrinology department between March 2015 and December 2017. A radiologist with 15 years of clinical ultrasound experience performed the bilateral lower limb artery ultrasound examinations on the patients.

About 37% of patients had MAC based on the ultrasound scan findings, but the diagnosis of mild and severe MAC differed based on the scoring approach. Using the length method, the researchers found 105 mild MAC cases and 123 severe cases, whereas the segmentation method identified 98 mild cases and 130 severe ones.

Both methods helped predict the odds of diabetic complications, including peripheral artery disease, peripheral neuropathy, retinopathy, and nephropathy. However, the segmentation method was also an independent predictor of peripheral artery disease and diabetic nephropathy, suggesting it may be better for evaluating cardiovascular abnormalities and risk for diabetes complications.

A main limitation of the study was that it only included ultrasound imaging instead of also using another imaging modality, the authors noted. However, it also demonstrated that two different ultrasound scoring methods can help predict diabetic complications -- although the segmentation might be better.

"MAC scores calculated by the segmentation method were significantly correlated with [peripheral arterial disease] and diabetic nephropathy," they concluded. "The segmentation method for assessing MAC may be a valuable tool in clinical work."