USPSTF advises against carotid artery stenosis screening

By Theresa Pablos, AuntMinnie staff writer

August 5, 2020 -- The U.S. Preventive Services Task Force (USPSTF) is poised to once again recommend against screening for asymptomatic carotid artery stenosis. The task force reaffirmed its D rating in a draft recommendation statement published on August 4.

The USPSTF last weighed in on the topic in 2014, concluding with moderate certainty that the harms of screening for carotid artery stenosis in the general population outweighed the benefits. In its new draft recommendation statement, the agency reaffirmed that position, stating there was not enough new evidence to change its previous recommendation against screening with either carotid duplex ultrasound, CT angiography, or MR angiography.

"The USPSTF found no new substantial evidence that could change its recommendation and therefore reaffirms its recommendation," the task force wrote.

In theory, screening the general population for stenosis could lead to early detection of narrowed blood vessels, thus enabling medical professionals to conduct potentially life-saving interventions, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS). But the USPSTF concluded that the evidence it reviewed didn't readily support that hypothesis.

The task force has consistently found limited evidence in favor of asymptomatic carotid artery stenosis screening, especially when compared with other medical therapies, such as statins and antihypertensive agents. And the evidence has been particularly lacking since the USPSTF's last review in 2014.

USPSTF draft recommendation rationale for asymptomatic carotid artery stenosis
Detection	Ultrasonography has reasonable sensitivity and specificity for detecting clinically relevant carotid artery stenosis, but it also yields many false-positive results in the general population.
	Scanning the neck for carotid bruits has poor accuracy for clinically relevant carotid artery stenosis.
Benefits	Direct evidence does not indicate that screening for asymptomatic carotid artery stenosis can improve stroke, mortality, or other adverse health outcomes.
	Carotid endarterectomy (CEA) or carotid artery angioplasty and stenting (CAS) provides little or no benefit for improving stroke, myocardial infarction, mortality, or other adverse outcomes compared with current medical therapy.
Harms	While direct evidence does not show that screening for asymptomatic carotid artery stenosis can cause harm, there are known harms with confirmatory testing and interventions.
	Direct evidence supports that treating asymptomatic patients with CEA or CAS could cause harms, including stroke or death.
	Harms related to screening and treating asymptomatic carotid artery stenosis have small-to-moderate magnitude.

After searching the scientific literature, USPSTF investigators found no recent eligible studies that directly investigated the benefits or harms of asymptomatic carotid artery stenosis screening. The two studies that were conducted on the topic in the past six years were both prematurely terminated and produced mixed results.

When looking at the benefits and harms of CEA or CAS, the authors found an additional two national datasets and three surgical registries that met their inclusion criteria. Rates of 30-day postoperative stroke or death after CEA ranged from 1.4% to 3.5% depending on the registry or database. Similarly, 30-day stroke or death after CAS ranged from 2.6% to 5.1%.

Based on the evidence -- or lack thereof -- the investigators concluded there wasn't enough new information to change the D rating for asymptomatic carotid artery stenosis screening. However, they pointed out that two clinical trials are currently underway, which may shed light on the topic in the future.

"There were few new trials, all with methodologic concerns, examining the important question of the comparative effectiveness and harms of revascularization plus best medical treatment compared with best medical treatment alone," they wrote. "The ongoing CREST-2 and ECST-2 trials will be the largest trials to address this issue."

The draft recommendation is available for public comment through August 31. After the comment period has ended, the task force will publish its final recommendation.

COVID-19 pandemic driving increase in ultrasound use

By Theresa Pablos, AuntMinnie staff writer

August 3, 2020 -- The COVID-19 pandemic is driving an increase in the use of lung ultrasonography among physicians in Italy, according to the results of a small survey published in the Journal of Ultrasound in Medicine.

More physicians said they're using ultrasound equipment now than before the pandemic, and experienced physicians are performing more lung ultrasound scans than ever before. The findings support anecdotal evidence that COVID-19 has increased interest in ultrasound, including among clinicians with no prior ultrasound experience.

"Thanks to online resources, many operators could e-learn and apply the technique," wrote the authors, Dr. Allessandro Zanforlin and Dr. Francesco Tursi, who are both members of the Italian thoracic ultrasound academy behind the survey (July 16, 2020, Journal of Ultrasound in Medicine).

The informal, one-week-long survey was conducted by Italian ultrasound society Academia di Ecografia Thoracia after the group noticed its membership spiked from 1,700 members in February to 4,000 members in May. The academy promoted its survey on social media and received 123 responses.

Survey respondents worked in a variety of settings, including on COVID-19 floors (34%), in intensive care units (31%), and in the emergency department (20%). The majority said they used lung ultrasound to monitor pneumonia (63%) and screen for COVID-19 (60%).

A total of 14% of respondents started using lung ultrasound exclusively because of the COVID-19 pandemic. Among these respondents, 81% said they learned how to perform lung ultrasound scans by following video tutorials or participating in webinars. The remaining 19% of respondents gained experience through expert mentoring or local courses.

As the number of patients with COVID-19 surged at hospitals in Italy, so too did the number of lung ultrasound exams. Respondents said the number of daily chest scans increased from an average of three per day before the pandemic to seven per day during the outbreak. For so-called "expert operators" with at least five years of lung ultrasound experience, the number of exams rose from five per day to nine per day.

The majority of respondents also said their lung ultrasound exams had increased in quality (58%) and accuracy (66%) during the pandemic. These percentages were even higher for participants who took an online course or webinar, with 83% of these respondents saying their exams increased in both quality and accuracy.

One factor driving the increase in lung ultrasound exams could be the availability of additional equipment thanks to donations and emergency purchase approvals. More than half of respondents said they acquired new ultrasound equipment during the pandemic, namely portable wheeled systems (37%) or handheld/wireless systems (19%).

The survey adds to the evidence that ultrasound is becoming an invaluable tool for care teams, especially those in Italy, who are treating patients with the novel coronavirus. However, the increase in skilled operators and new equipment may mean the modality will remain prominent for lung imaging even after the pandemic is over.

"What we are learning from this pandemic is the importance of [lung ultrasound] in the diagnosis, evaluations, and monitoring of pneumonia, which, in the hands of many physicians ... could improve the quality of the treatment of respiratory patients," the authors concluded.

US correlates with COVID-19 severity, duration

By Theresa Pablos, AuntMinnie staff writer

July 28, 2020 -- Findings on lung ultrasound scans were correlated with COVID-19 severity and duration in a study published on July 23 in the American Journal of Roentgenology. In particular, pulmonary consolidations distinguished between patients with moderate and severe forms of the novel coronavirus disease

The study included dozens of patients who were consecutively treated for COVID-19 at a Chinese hospital in March. The findings may aid physicians in managing patients with moderate-to-severe COVID-19, the authors noted.

"Our results indicate that lung [ultrasound] findings can be used to reflect both the infection duration and disease severity," wrote the authors, led by Dr. Yao Zhang from Ditan Hospital in Beijing.

Zhang and colleagues enrolled 28 patients consecutively hospitalized for COVID-19 at their institution between March 1 and March 30. The patients all tested positive for the novel coronavirus on a nasopharyngeal test and underwent a bedside lung ultrasound scan in a sitting, supine, and decubitus position.

Every patient in the study had B-lines on their ultrasound scans, which indicate areas of increased interstitial fluids and decreased alveolar air. Another two-thirds of patients had pulmonary consolidation, and 61% had a thickened pleural line. Only one patient had a pleural effusion.

Pulmonary consolidation occurred significantly more often in patients with severe or critical COVID-19 than patients with moderate disease, the authors found. Almost 87% of patients with severe or critical disease had pulmonary consolidation on ultrasound, compared with just 46% of patients with moderate COVID-19.

(A) Lung ultrasound image obtained with a convex probe. The outer arrows show confluent B-lines. The middle arrowheads point to a thickened pleural line. (B) Lung ultrasound image obtained with a linear probe. The arrow points to a B-line. The star denotes a patchy pulmonary consolidation. (C) Chest CT image showing reticular and interlobular septal thickening and patchy, focal opacities associated with architectural distortion. Image courtesy of the American Journal of Roentgenology.

Furthermore, patients with a thickened pleural line had experienced a longer infection period than those without a thickened pleural line. Patients with fewer than 20 days between the day they first noticed COVID-19 symptoms and the day of their ultrasound scan were significantly less likely to have a thickened pleural line than those with a difference of 20 days or more.

The study findings add to the growing body of research demonstrating that severity on lung ultrasound scans can predict worse outcomes and even mortality for patients with COVID-19. The authors emphasized that ultrasound also has unique benefits over other imaging modalities, including CT, for treating patients with the novel coronavirus.

"[Ultrasound] is repeatable in critically ill patients, which ensures that monitoring of the severity of the disease and the effects of therapies can be easily carried out," they wrote. "This capability is particularly important in situations in which chest CT is not available, such as in isolation wards and [intensive care units]."

The authors cautioned that their study focused on a small number of patients and did not evaluate how ultrasound findings might have changed over time. They hope future studies will continue to study the use of lung ultrasound for COVID-19, particularly how lung ultrasound scoring systems might improve COVID-19 assessment and treatment.

"Lung [ultrasound] was highly sensitive for detecting abnormalities in patients with COVID-19, and B-lines, a thickened pleural line, and pulmonary consolidation were the most commonly observed features," the authors concluded.

A New Standardize Doppler waveform reporting

By Theresa Pablos, AuntMinnie staff writerJuly 24, 2020 -- A new set of guidelines aims to standardize the terminology used to report arterial and venous spectral Doppler ultrasound waveforms. The document was jointly published on July 15 in Vascular Medicine and the Journal for Vascular Ultrasound.

The statement creates a designated set of key terms to describe findings on spectral Doppler ultrasound waveforms, the main diagnostic assessment for arterial and venous diseases. It was written by sonographers, vascular specialists, and other experts commissioned by the Society of Vascular Medicine and Society of Vascular Ultrasound.

"The hope of the writing committee is that this document will help us all to 'speak the same language,' and thereby advance the field of vascular ultrasound and improve patient care," stated lead study author Dr. Esther Kim, vascular labs medical director at Vanderbilt University Medical Center, in a press release.

The lack of shared nomenclature has been an ongoing problem for vascular ultrasound professionals. In fact, one out of five ultrasound professionals has had to perform a repeat arterial Doppler ultrasound examination because of terminology differences, according to a survey cited in the consensus statement.

"Over a decade ago, the lack of a standardized nomenclature to describe spectral Doppler waveforms was demonstrated to result in confusion amongst ultrasound professionals," Kim stated. "Not surprisingly, this can lead to negative clinical outcomes."

In the consensus statement, the committee established three major descriptors for ultrasound waveforms: flow direction, phasicity, and resistance for arterial waveforms and flow direction, flow pattern, and spontaneity for venous waveforms.

Major descriptors for arterial ultrasound waveforms
Flow direction	Antegrade Blood flows in normal direction Previously known as forward flow
	Retrograde Blood flows in opposite direction Previously known as reverse flow
	Bidirectional Blood enters and leaves through the same opening Previously known as to-fro
	Absent No detected blood flow
Phasicity	Multiphasic Waveform crosses zero-flow baseline Previously known as triphasic or biphasic
	Monophasic Waveform does not cross zero-flow baseline Blood flows in single direction
Resistance	High resistive Sharp upstroke and brisk downstroke
	Intermediate resistive Visible end-systolic notch Continuous flow above the zero-flow baseline
	Low resistive No end-systolic notch Prolonged downstroke in late systole

Major descriptors for venous ultrasound waveforms
Flow direction	Antegrade Blood flows in normal direction Previously known as central or forward flow
	Retrograde Blood flows in opposite direction Previously known as peripheral or reverse flow
	Absent No detected blood flow
Flow pattern	Respirophasic Flow velocity related to respiratory cycle Previously known as respiratory phasicity
	Decreased Respirophasic flow with less variation than expected Previously known as dampened or blunted
	Pulsative Flow velocity is inversely linked to cardiac cycle Previously known as cardiophasic
	Continuous Respiratory/cardiac cycles do not affect flow velocity Steady Doppler signal with minimal variation
	Regurgitant Flow velocity varies with cardiac cycle
Spontaneity	Spontaneous Blood flows without external influence
	Nonspontaneous Blood flows only with external maneuvers

The statement also established terms that can be used to modify the main descriptors. For arterial waveforms, the seven modifying terms are as follows:

1. Rapid upstroke -- Near vertical rise to peak systole
2. Prolonged upstroke -- Abnormally gradual slope to peak systole; previously known as tardus, delayed, or damped upstroke
3. Sharp peak -- Single, well-defined peak
4. Spectral broadening -- Widening of the velocity band or filling in the typically clear area under the systolic peak; previously known as nonlaminar, turbulent, disordered, or chaotic
5. Staccato -- High-resistance pattern with a short, low-amplitude diastolic signal punctuated by spikes of acceleration and deceleration
6. Dampened -- Abnormal upstroke and peak, typically with decreased velocity; previously known as parvus et tardus, attenuated, or blunted
7. Flow reversal -- Flow that changes direction but not as part of normal flow, can be transient or consistent with the cardiac cycle; previously known as pre-steal, competitive flow, or oscillating

For venous waveforms, the three modifying terms as follows:

1. Augmentation -- Changes in flow velocity related to physical maneuvers, can be described as normal, reduced, or absent augmentation
2. Reflux -- Persistent retrograde flow beyond normal closure time
3. Fistula flow -- Flow with an arteriovenous fistula that becomes pulsatile due to communication with artery, sharp peaks often appear as pulsatile; previously known as arterialized or fistulous

In addition to creating the key descriptors and modifiers, the statement defined the reference baseline for spectral Doppler waveforms as the zero-flow baseline. It also advised against using the terms "normal" or "abnormal" to describe a waveform, since what is normal will depend on the part of the body and situation.

The statement also instructed sonographers to use image optimization techniques to acquire quality Doppler waveforms. This includes using an optimal transducer-to-vessel angle, the normal peripheral artery systolic waveform acceleration of 0.2 seconds, and proper transducer support.

Finally, the committee advised sonographers to provide complete descriptions for referring providers, including indication, relevant history, velocity measurements, and waveform characteristics. Sonographers should also include a conclusion with the clinical indication.

"We hope that this new Doppler waveform nomenclature will eliminate confusion and lead to appropriate diagnosis and better patient care," stated Dr. Raghu Kolluri, president of the Society of Vascular Medicine.

POCUS PHÁT HIỆN U HỐC MẮT

NEGATIVE Y SIGN=NONRECURRENT LARYNGEAL NERVE

POCUS Findings can Predict COVID-19 Death Risk

By Theresa Pablos, AuntMinnie staff writer

July 17, 2020 -- The findings on initial lung scans with point-of-care ultrasound (POCUS) can predict which patients with COVID-19 are at a greater risk of death, according to a prospective study from Italy published on July 15 in Ultrasound in Medicine & Biology.

Physicians in Rome performed lung ultrasound scans on 41 adult patients who visited a tertiary emergency department with symptoms of the novel coronavirus disease. Patients who later died or were later admitted to the intensive care unit (ICU) had significantly worse pathological findings on their initial scan.

"Our study shows that [lung ultrasound scan] is able to detect COVID-19 pneumonia and to predict, during the first evaluation in the emergency department, patients at risk of intensive care unit admission and death," wrote the authors, led by Nicola Bonadia, from the department of emergency medicine at Agostino Gemelli University Policlinic.

Physicians performed point-of-care ultrasound (POCUS) scans on all patients with suspected cases of COVID-19 who visited the emergency department in March. The emergency department staff used a pocket device with a wireless 6-MHz convex probe and followed a previously described lung ultrasound protocol that includes 14 chest areas.

Each scanned area received a numeric score of 0 to 3 based on the severity of the findings in that section. A higher lung ultrasound score (LUS) signified worse disease severity, with a score of 3 indicating dense or large areas of white lung with or without subpleural consolidations.

The authors analyzed the lung ultrasound findings from 41 patients with a positive SARS-CoV-2 test result and known outcomes. They specifically excluded children and patients with less than six months life expectancy due to preexisting chronic conditions, such as advanced cancer or dementia.

More than 90% of adult patients with COVID-19 had at least one area with an abnormal lung ultrasound finding. Pathological findings occurred in all 14 scanned areas but were most prominent in the lateral lung regions, the authors noted.

Patients with fatal cases of COVID-19 had pathological findings in 100% of scanned areas, compared with just 50% of scanned areas in discharged patients. These patients also had a mean lung ultrasound score of 1.43, compared with 1.0 in discharged cases.

Similarly, patients admitted to the ICU had pathological findings in 93% of scanned areas, compared with just 20% of areas in patients not admitted to the ICU. ICU patients also had a mean LUS of 1.36, compared with 1.0 in non-ICU patients.

Based on their findings, the authors determined the cutoff for a strict definition of COVID-19 pneumonia should be an LUS of 0.4 and a pathological findings rate of at least 20%. Furthermore, no study participants died if they had a mean LUS less than 1.1 and an average pathological rate under 70%.

The authors cautioned their study took place at one institution and had a small sample size. Nevertheless, the findings may help health professionals better triage patients with COVID-19 and spur future studies to evaluate whether lung ultrasound scores can guide patient treatment and admission decisions.

"We found a significant correlation between ultrasound findings and severity of the disease, assessed as mortality and need for ICU admission," the authors wrote. "To our knowledge, this is the first study describing the predictive role of LUS in patients with COVID-19."

US SWE ở trẻ em

In fact, for pSWE and 2D-SWE experience in B-mode US is mandatory. Data acquisition should be undertaken by specialists. Operators experienced both in ultrasonography and elastography are needed to obtain reliable liver stiffness measurements in children, considering the different anatomy, especially in babies (liver situated lower in the abdomen), and the fact that cooperation from a small child is sometimes difficult. The location for measurements can be more difficult to establish in children and here the operator’s experience can play a role.

Neonatal brainSome early reports on the use of transcranial SWE of the periventricular brain parenchyma, in preterm infants and infants with hydrocephalus, suggest that SWE is possible and technically feasible [101,102] (fg 5, fg 6).
Albayrak et al showed that differences between brain stiffness values in preterm and term neonates can be demonstrated by using 2D-SWE. Brain stiffness measured from both the thalamus and periventricular white matter were found to be signifcantly lower in preterm neonates compared with term neonates (cut-off values for determining prematurity less than 8.28 kPa for mean
thalamus stiffness and less than 6.59 kPa for periventricular white matter stiffness). The authors suggested that the results might be reference points for evaluating neonatal brain stiffness in research on patients with various illnesses. 2D-SWE also seems to have the ability to depict increased intracranial pressure (ICP) in infants, with a positive linear correlation between SWE values and ICP
[102]. Infants with ICP seem to have increased 2D-SWE values (mean 24.2±5.1 kPa) compared to healthy infants (mean 14.1±6.6 kPa). However, larger prospective studies are still not available. If these preliminary observations of the benefts of transcranial SWE of the neonatal brain will be confrmed by further studies, SWE might be a useful method for additional diagnostic imaging and
monitoring in premature infants and children with proven or suspected increased ICP. When performing SWE of the neonatal brain, potential risks and harms of applying high energy levels by US to the neonatal brain should be considered. Recently, an experimental study on mice dealing with the potential biological effects associated with 2D-SWE on the neonatal brain was published [103].
The results indicated that 2D-SWE does not cause detectable histologic changes in the brain of neonatal mice, nor does it have long-term effects on the learning and memory abilities. However, some temporary effects were observed when the scanning lasted for more than 30 min. Thus, it is recommended to pay attention to the scanning duration when assessing neonatal brains with 2D-     SWE elastography.  

The examiner should acquire appropriate knowledge and training in US elastography [104,105]. The operator Fig 5. SWE of the neonatal brain in a healthy newborn (14 days old). Sagittal view of the periventricular region in a healthy newborn. B-mode shows no abnormalities 

(a). 2D-SWE shows a mean periventricular tissue stiffness of 13.5 kPa and a maximum value of 14.8 kPa 

(b). must distinguish a good B mode US image from suboptimal images.