Pediatric EDs using more ultrasound, MRI instead of CT

By Erik L. Ridley, AuntMinnie staff writer

August 3, 2020 -- Although pediatric emergency departments (EDs) performed fewer CT exams between 2009 and 2018, their utilization of advanced imaging increased overall due to expanded use of MRI and ultrasound exams, according to research published online August 3 in JAMA Pediatrics

A research team led by Dr. Jennifer Marin of UPMC Children's Hospital of Pittsburgh assessed the change in CT, ultrasound, and MRI rates in over 26 million ED visits archived in the Pediatric Health Information System administrative database from January 1, 2009, to December 31, 2018.

They found that the proportion of pediatric ED encounters that resulted in a CT exam decreased amid expanded use of ultrasound and MRI. But there was also considerable variation in utilization between practices.

"The magnitude of the decrease in CT use varied by site and was associated, in part, with the use of alternative advanced imaging modalities for certain diagnoses, most notably ultrasonography for abdominal conditions," they wrote. "Future efforts appear to be needed to standardize imaging approaches and evaluate the effect of the changing

landscape of advanced imaging on patient-level outcomes."

Change in use of advanced imaging in pediatric ED
	2009	2018
At least one advanced imaging study	6.4%	8.7%
CT	3.9%	2.9%
Ultrasound	2.5%	5.8%
MRI	0.3%	0.6%

*All differences were statistically significant (p < 0.001, p = 0.001, p < 0.001, and p < 0.001, respectively).

Delving further into the data, the researchers found that most of the decrease in CT occurred in eight all patient-refined diagnosis-related groups (APR-DRGs), led by concussion (-23%), appendectomy (-14.9%), ventricular shunt procedures (-13.3%), and migraine and other headaches (-12.4%). Declines in CT use also occurred in other disorders of the nervous system (-10.1%); abdominal pain (-6.1%); other ear, nose, mouth, throat, and cranial or facial diagnoses (-5.9%); and seizure (-5.3%).

The researchers also found that strategies to reduce abdominal CT use by performing ultrasound first for evaluating abdominal pain may be associated with the higher use of ultrasound for that application.

"Interestingly, the increase in the use of ultrasonography for these conditions was greater than the decrease in the use of CT," they wrote. "Therefore, a proportion of these ultrasonographic examinations likely represent overuse of a typically widely available and nonradiating imaging tool."

In other findings, the researchers observed wide variation among EDs in the use of ultrasound for appendectomy (median 57.5%), as well as MRI (median 15.8%) and CT (median 69.5%) for ventricular shunt procedures.

In terms of outcomes, the researchers found that hospitalization and three-day ED revisits decreased during the study period. However, the ED length of stay did not change.

While it's encouraging that lower utilization of CT avoided radiation exposure in nearly 28,000 fewer kids, the increase in the number of children receiving at least one form of advanced imaging was less encouraging from a healthcare value perspective, according to an accompanying editorial by Dr. Alan Schroeder and Dr. Alan Imler of Stanford University in Palo Alto, CA.

Although outcomes appeared to have improved somewhat during the study period, other secular trends -- such as heightened public awareness of concussions -- might also explain those outcomes, wrote Schroeder and Imler. Increased imaging among patients who were ultimately hospitalized also further suggests that the more imaging is not associated with reduced hospitalization. 

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.