ABUS deliveres better diagnostic performance

By Wayne Forrest, AuntMinnie.com staff writer

December 9, 2019 -- Both automated breast ultrasound (ABUS) and traditional handheld ultrasound can significantly improve breast cancer detection when used as an adjunct to mammography in women with dense breasts. But ABUS yields better diagnostic performance, according to research presented at RSNA 2019 in Chicago.

In a study involving over 1,200 women, a team of researchers led by Dr. Mengmeng Jia of the Chinese Academy of Medical Sciences in Beijing found that ABUS produced a higher specificity, positive predictive value, and area under the curve (AUC) than handheld ultrasound.

Breast cancer is the most commonly diagnosed cancer in Chinese women, but less than 1% of cases are detected by screening, according to Jia. Compared with Western countries, Chinese women also have a higher proportion of dense breasts, for which mammography is less sensitive, she said. As a result, these patients need adjunctive imaging modalities such as ultrasound, digital breast tomosynthesis, or MRI.

Traditional handheld ultrasound is inexpensive, safe, and suitable for dense breasts. But it's also labor intensive and highly dependent on the operator. ABUS, on the other hand, is specifically designed for finding cancer in dense breast tissue. It's also reproducible due to its operator-independent acquisition method, Jia noted.

"Most importantly, the image acquisition can be separated from interpretation," she said. "That means that images can be taken by the operator and then interpreted by radiologists [at another location]. That is helpful in resource-limited areas [where there are not enough qualified radiologists]."

The researchers sought to evaluate the diagnostic performance of ABUS and handheld ultrasound as an adjunct to mammography in women ages 40 to 69. They also wanted to assess the performance of both methods in mammography-negative dense breasts.

The team enrolled 1,266 women ages 40 to 69 in a multicenter study involving five tertiary hospitals. All women received mammography, as well as handheld ultrasound and ABUS. Of the 1,266 women, 958 were deemed to have dense breasts.

Overall, sensitivity increased from 87.3% with mammography alone to 96.9% for both handheld ultrasound and ABUS. Negative predictive value also increased from 95.5% to 98.8% with handheld ultrasound and 98.8% for ABUS. Mammography alone had an AUC of 0.88, compared with an AUC of 0.92 for mammography and handheld ultrasound and 0.93 for mammography and ABUS.

In women with mammographically negative dense breasts, ABUS and handheld ultrasound detected 31 additional cases of breast cancer. The techniques had comparable sensitivity and negative predictive value, but ABUS had a higher specificity, positive predictive value, and AUC, according to the researchers.

Performance in women with mammographically negative dense breasts
	Handheld ultrasound	ABUS
Sensitivity	31/33 (93.9%)	31/33 (93.9%)
Specificity	619/665 (93.1%)	635/665 (95.5%)
Positive predictive value	31/77 (40.3%)	31/61 (50.8%)
Negative predictive value	619/621 (98.8%)	635/637 (99.7%)
Area under the curve	0.935	0.947

"More studies are [now] needed to [further] evaluate the performance of adjunctive ultrasonography, including ABUS and handheld ultrasound,  in [resource]-limited areas," Jia concluded.

Are clinicians overusing CTA for carotid stenosis?

By Abraham Kim, AuntMinnie.com staff writer

December 9, 2019 -- The use of CT angiography (CTA) as the first-line imaging exam for carotid artery stenosis has increased nearly threefold during the past several years, raising concerns over growing patient costs and radiation exposure, according to a study presented on Friday at RSNA 2019.

The researchers, led by Dr. Jina Pakpoor from Johns Hopkins Hospital, examined imaging requests for the diagnosis of carotid artery stenosis from outpatient centers across the U.S. Their analysis of the data revealed that CTA usage rates increased every year from 2011 to 2016, whereas ultrasound usage steadily trended downward.

"Overall, there is actually high compliance with the current recommendation to use Doppler ultrasound for initial testing," Pakpoor told session attendees. "We did, however, find that there was a shift in the direction, where CTA use is increasing and Doppler ultrasound use is actually decreasing, which is going to have higher costs for patients and higher radiation exposure."

CTA on the rise

Current guidelines from the Society of Vascular Surgery recommend Doppler ultrasound as the first-line imaging exam for carotid stenosis. More advanced imaging exams such as CTA and MR angiography (MRA) are typically reserved as a second-line imaging test for cases requiring more detailed stenosis characterization or urgent therapy.

Dr. Jina Pakpoor.

However, recent studies have shown that CT usage rates have increased dramatically for carotid imaging in general over the past decade, whereas rates for other imaging modalities have been decreasing. These reports motivated Pakpoor and colleagues to determine whether physicians in the U.S. were complying with existing guidelines for the initial imaging workup of suspected carotid artery stenosis in the outpatient setting.

The researchers obtained information from the 2011 to 2016 IBM MarketScan U.S. national commercial claims and insurance database, which includes data submitted by large employers, managed care organizations, hospitals, electronic medical record providers, Medicare, and Medicaid.

The study population included 229,464 patients ages 18 to 65 who underwent neck CT angiography, Doppler ultrasound, or MR angiography for their first carotid stenosis encounter. Approximately half of the patients were male, and their average age was 55.

Over the eight-year period, the vast majority of patients received an ultrasound exam at 95.8%, followed by CTA at 2.4%, and finally MRA at 1.3%.

Though ultrasound remained by far the most used imaging modality overall, a year-by-year analysis showed that the ultrasound usage rate decreased by a statistically significant degree from 2011 to 2016. In contrast, the usage rates roughly tripled for CTA and remained relatively constant for MRA.

Trends in carotid stenosis detection on ultrasound, MRA, and CTA
	2011			2016
	Ultrasound	MRA	CTA	Ultrasound	MRA	CTA
Proportion of all imaging exams	96.9%	1.2%	1.6%	93.8%	1.5%	4.7%

The differences by year were statistically significant for ultrasound and CTA (p < 0.001).

Room for concern

Further analysis revealed that use of CTA and MRA varied depending on the region of the U.S. where the exams were performed. To be specific, combined CTA and MRA use was considerably greater in the western U.S. (5.5%) than in the northeastern U.S. (2%; p < 0.001). In addition, females were more likely than males to receive advanced imaging.

Though most referring providers appear to be complying with current recommendations for the diagnosis of carotid stenosis, the sustained increase in CTA utilization poses a concern, Pakpoor noted. Growing reliance on CTA for first-line imaging may stem from the increasing availability of CT scanners throughout the U.S.

"These days a lot of institutions have CT scanners available in the emergency department, and CT is known as a modality that you can easily and quickly get access to," she said. "And from a provider's perspective, if you're not worried about practice costs and radiation, CTA can provide a lot more information and avoid the need for a second [imaging] study. But it is not the current recommendation, and we don't want people to be moving in that direction."

The findings suggest a possible need to educate outpatient providers on the appropriate protocol in order to prevent this trend from continuing in the same direction, Pakpoor concluded. "It will certainly be something important to look at in the future -- to emphasize the importance of continuing to use Doppler ultrasound as the first modality, despite the fact that we're seeing an increase in use of CT over all aspects of radiology."

LOW BACK PAIN and ULTRASOUND

FETAL BIOMETRY GUIDELINES

CONCLUSION

The performance and interpretation of fetal biometry is an important component of obstetric ultrasound practice. In fetuses for which gestational age has been established appropriately, measuring key biometric parameters, together with transformation of these measurements into EFW using one of the many validated formulae, permits detection and monitoring of small fetuses. Serial sonographic assessment of fetal size over time can provide useful information about growth, with the possibility of improving the prediction of SGA infants, particularly those at risk for morbidity. However, errors and approximations that may occur at each step of such a process greatly hamper our ability to detect abnormal growth, and most importantly FGR. Therefore, in clinical practice, fetal biometry should represent only one component of how we screen for abnormal growth. It is reasonable to believe that no single measurement, EFW formula or chart will significantly improve our current practices. Improved FGR screening may be feasible by using a combined approach that includes biometry as well as other clinical, biological and/or imaging markers. This goal will come within reach only when the ‘biometric component’ is better standardized for all those who care for pregnant women.

SIÊU ÂM MỠ THÀNH BỤNG VÀ DÀY NỘI MẠC ĐỘNG MẠCH CẢNH