SWE and plantar fasciitis diagnosis.

By Kate Madden Yee, AuntMinnie.com staff writer

June 3, 2019 -- Shear-wave elastography (SWE) boosts diagnostic accuracy in patients with plantar fasciitis, according to a new study published online May 30 in Academic Radiology.

And its diagnostic power is even greater when it's combined with B-mode ultrasound, yielding 100% sensitivity, according to a team led by Dr. Matthias Gatz of University Hospital RWTH Aachen in Germany.

"[Our] study showed for the first time that SWE has an additive diagnostic value for diagnosing plantar fasciitis, with a sensitivity of 100% for the combined usage of SWE and B-mode ultrasound," the group wrote. "Additionally, the diagnostic accuracy increased from 79% using B-mode ultrasound to 84% using SWE."

The current standard for diagnosing plantar fasciitis is B-mode ultrasound to identify hypoechoic areas, border irregularities of the fascia, and calcifications. In particular, plantar fascia thickness of more than 4 mm is the key diagnostic sign for diagnosing fasciitis with B-mode ultrasound. But since fascia thickness can actually decrease over time, even in patients with fasciitis, B-mode ultrasound can miss fasciitis cases.

Gatz and colleagues hypothesized that SWE would be more effective in diagnosing fasciitis because it measures tissue stiffness and can therefore identify the condition even if the fascia isn't thickened, according to the group. The technique may also be more effective than B-mode ultrasound for monitoring the effects of treatment, according to the team.

To investigate, the group conducted a study that included 82 patients with plantar fasciitis. These patients were divided into three groups: symptomatic (39), asymptomatic (23) and bilateral asymptomatic (20). The reference standard for the study was B-mode ultrasound findings of a plantar fascia thickness greater than 4 mm. The researchers measured shear-wave tissue elasticity at the calcaneus, at 1 cm away from the calcaneus, and at the central part of the calcaneus. The group then calculated sensitivity, specificity, and diagnostic accuracy of SWE compared with B-mode ultrasound.

Gatz's team found that SWE was more sensitive and more diagnostically accurate than B-mode ultrasound alone, although it was less specific.

SWE compared with B-mode ultrasound for diagnosis of plantar fasciitis
Performance measure	B-mode	SWE
Sensitivity	61%	85%
Specificity	95%	83%
Diagnostic accuracy	79%	84%

Sensitivity and diagnostic accuracy were highest when the two techniques were combined, at 100% and 90%, respectively.

The study results show that SWE can boost B-mode ultrasound's performance -- good news for patients with a condition like plantar fasciitis, which doesn't necessarily present in a way ultrasound can identify, according to Gatz's team.

"SWE provides a quantitative assessment of plantar fasciitis integrity and can distinguish between symptomatic and asymptomatic patients better than B-mode ultrasound," the group concluded.

Ultrasound for evaluating liver steatosis.

By Kate Madden Yee, AuntMinnie.com staff writer

May 31, 2019 -- Ultrasound is a reliable alternative to MRI for assessing liver steatosis in the clinical setting, according to a study published in the July issue of Clinical Radiology. The findings offer clinicians a cost-effective, accessible option for evaluating steatosis.

While MRI has become an accepted modality for detecting liver steatosis, it comes with a high cost and is generally less available than other modalities, according to a team led by Dr. Marie-Luise Kromrey of University Medicine Greifswald in Germany. "Ultrasonography is commonly used to detect liver steatosis and has the advantage of being cost-effective, simple, and widely available," the team wrote.

Fat storage in the liver can be an indicator of metabolic syndrome, a condition characterized by insulin resistance and a precursor to type 2 diabetes. Since liver steatosis is also a risk factor for a variety of other diseases, having an effective way to assess it is important, Kromrey and colleagues noted.

Yet although ultrasound is regularly used to detect liver steatosis, its diagnostic accuracy and reliability for assessing the severity of fatty liver have been unclear. So Kromrey and colleagues conducted a study to compare the modality's performance to that of MRI.

The study included 2,783 patients who underwent 1.5-tesla MRI scans of the liver; from these MRI exams, the group calculated proton-density fat fraction and transverse relaxation rate to estimate liver steatosis and iron overload. Patients also underwent B-mode ultrasound. Kromrey's team then assessed the sensitivity and specificity of ultrasound to identify different degrees of steatosis and amounts of liver iron (Clin Radiol, July 2019, Vol. 74:7, pp. 539-546).

MRI showed liver steatosis in 40% of participants (mild, 68.9%; moderate, 26.7%; severe, 4.4%), while ultrasound found liver steatosis in 37.8%, which corresponded to a sensitivity of 74.5% and a specificity of 86.6%.

The group also found that ultrasound sensitivity increased with the amount of liver fat present (65.1% for low fat content, 95% for moderate fat content, and 96% for high fat content). Liver iron did not affect ultrasound's ability to detect liver steatosis, Kromrey and colleagues noted.

"The present results show excellent sensitivity and specificity of ultrasound for the estimation of fatty liver disease in patients with moderate and high liver fat content," the group wrote.

However, since ultrasound didn't perform as well in patients with low liver fat content, additional evaluation methods may still need to be used, according to the team.

"The weakness of ultrasound in assessing small amounts of liver fat should be considered and compensated by additional liver enzyme quantification or MRI," the authors concluded.