VTTI Assessment of Thyroid Nodules for Biopsy

Point-of-Care Ultrasound Helps Find Fluid

By Kate Madden Yee, AuntMinnie.com staff writer

October 26, 2017 -- Point-of-care ultrasound (POCUS) is an effective tool that is increasingly being implemented to help diagnose disease and plan treatment. The technology is particularly useful for finding fluid, according to a study published online October 23 in JAMA Internal Medicine.

Dr. Rachel Liu from Yale School of Medicine.

Localizing fluid can make ensuing procedures safer and more effective, according to a team led by Dr. Rachel Liu of Yale School of Medicine.

"[Point-of-care ultrasound] can improve the safety and success of accessing fluid-filled spaces through procedural guidance, and guidelines increasingly recognize ultrasonographic guidance as the standard of care," the group wrote.

However, POCUS does require some skill, according to Liu and colleagues.

"Appropriate use of point-of-care ultrasound requires investment in equipment, adequate education and training, and understanding limitations of both the technology and the user," the researchers wrote. "Performing high-quality POCUS requires comprehension of basic concepts in ultrasonography, knowledge of normal and pathological anatomy, and skill in both acquiring and interpreting images."

Particular procedures

POCUS has been shown to reduce hospital stays and healthcare costs, while also improving diagnostic accuracy and the safety and success of procedures, Liu and colleagues wrote. In fact, some compare it to the stethoscope in its potential to influence medical practice (JAMA Intern Med, October 23, 2017).

"Just as the stethoscope improved upon existing examination techniques, POCUS used by medical students and residents with focused training has been shown to offer more diagnostic accuracy than either their own physical examinations or those of experienced clinicians," the researchers wrote.

Liu's team reviewed the principles of diagnostic and procedural ultrasound, outlining its utility in finding and accessing fluid in key thoracic and abdominal areas as a supplement to basic diagnosis and procedures. A few clinical applications are as follows:

• Pulmonary edema. Ultrasound can image the pleural line, where the interaction of the parietal and visceral pleura creates a sliding appearance of lung pleura against the chest wall, the group wrote. The presence of abnormal interstitial fluid is called alveolar interstitial syndrome and can cause pulmonary edema or fibrosis. It can be identified by detecting ultrasound B-lines (the reverberation artifact at the pleural line). A linear probe works best for imaging the pleural line and should be oriented sagittally with the indicator toward the patient's head, Liu and colleagues noted.
  "Most often in the acute medical setting, assessment for B-lines is performed when there is concern for fluid overload states or decompensated heart failure," they wrote.
• Pericardial effusion. Practitioners should use a phased-array probe to evaluate this condition, which can be fatal. The pericardium will appear as a hyperechoic layer around the heart, and effusion will appear as an anechoic or hypoechoic space between the visceral and parietal layers, according to the researchers.
  "While large effusions are often straightforward to diagnose, it is important to be aware of the normal appearance of pericardial fatty tissue to avoid overcalling an effusion," they wrote.
• Peritoneal fluid. Ultrasound is the gold standard for diagnosing ascites, or the buildup of protein-containing fluid within the abdomen. It can identify as little as 100 mL of fluid, while physical examination is estimated to be about 45% to 84% sensitive and 59% to 90% specific, with overall accuracy under 60%, according to Liu's team.
  "The curvilinear probe should be used to assess for intraperitoneal fluid, but a phased-array probe may also suffice," the group wrote. "Typically, the examination begins with the probe placed on the right flank at the midaxillary line, using a coronal orientation."
• Fluid removal. Ultrasound can improve the success of paracentesis and thoracentesis by detecting the largest areas of fluid closest to the skin surface, Liu and colleagues noted. All three probes can be used: The curvilinear and phased array may be more helpful in delineating fluid, while the linear probe offers superficial detail. POCUS has been shown to improve the success of paracentesis compared with the traditional method of using anatomical landmarks, and ultrasound-guided thoracentesis has been shown to reduce morbidity associated with complications from the procedure, such as pneumothorax, the group wrote.

Take time for training

POCUS is a user-dependent technology in two respects: image acquisition and interpretation, Liu's group noted. It definitely requires some training.

"Physicians may think that POCUS is intended to answer yes or no questions -- that it's binary, so it's easy," Liu told AuntMinnie.com. "And sure, the concept of finding fluid isn't rocket science. But a good amount of practice and training is still needed to be accurate in diverse clinical situations. A medical student can pick up a probe and start doing it right away to help learn anatomy, but making complex clinical decisions using POCUS requires dedicated practice."

Are physicians being trained to use ultrasound? Not as they could be, the researchers found. In 2014, only 28% of U.S. medical schools reported having a formal curriculum for ultrasonography, and in 2013, only about a fourth of entering residents reported exposure to bedside ultrasound.

So it's extra important to institute a training program for POCUS, including how to handle incidental findings, Liu and colleagues wrote.

"Ideally, POCUS would be incorporated longitudinally into residency training and overseen by experienced faculty, although this may take time to develop," they wrote. "Learning ultrasonography requires didactic and hands-on instruction combined with proctored clinical use."

Leading the charge

That physicians across many specialties -- emergency department, intensive care, and family practice -- are interested in POCUS is good news for radiology, according to Liu.

"Radiologists can help train other physicians in point-of-care ultrasound -- for example, some have instituted hands-on participation during ward rounds, or they hold regular image review and quality assurance sessions with nonradiology physicians," she told AuntMinnie.com. "Also, some emergency departments employ sonographers to help with residency training and medical student education."

In fact, radiology concepts aren't necessarily emphasized in medical school, and radiologists can help remedy that, she said.

"Medical students might see a CT image next to an anatomy slide, but they don't necessarily learn about imaging at the same time," she said. "These are future doctors who will be making diagnostic decisions for patients, and it would be helpful for them to have a solid understanding of imaging concepts before they begin residency."

Acute Flank Pain: Renal Stones and Acute Pyelonephritis

Abstract

Ultrasonography is a useful tool for the differential diagnosis of acute flank pain. Renal stones appear as a focal area of echogenicity with acoustic shadowing on ultrasonography. In acute pyelonephritis (APN), the kidneys may be enlarged and have a hypoechoic parenchyma with loss of the normal corticomedullary junction. However, clinical and laboratory correlations are essential for the diagnosis of renal stones and APN through imaging studies. This review describes the typical ultrasonography features of renal stones and APN. Moreover, in daily practice, cross-sectional imaging is essential and widely used to confirm renal stones and APN and to differentiate them from other diseases causing flank pain. Other diseases causing acute flank pain are also described in this review.

Keywords: Ultrasonography; Kidney; Urinary calculi; Pyelonephritis

Liver stiffness in nonalcoholic fatty liver disease: A comparison of supersonic shear imaging, FibroScan, and ARFI with liver biopsy

Further Readings

gan tham mo va sieu am dan hoi

ROTATOR INTERVAL

Abstract

 Shoulder pathologies of the rotator cuff of the shoulder are common in clinical practice. The focus of this pictorial essay is to discuss the anatomical details of the rotator interval of the shoulder, correlate the anatomy with normal ultrasound images and present selected pathologies. We focus on the imaging of the rotator interval that is actually the anterosuperior aspect of the glenohumeral joint capsule that is reinforced externally by the coracohumeral ligament, internally by the superior glenohumeral ligament and capsular fibers which blend together and insert medially and laterally to the bicipital groove. In this article we demonstrate the capability of high-resolution musculoskeletal ultrasound to visualize the detailed anatomy of the rotator interval. MSUS has a higher spatial resolution than other imaging techniques and the ability to examine these structures dynamically and to utilize the probe for precise anatomic localization of the patient’s pain by sono-palpation.

Zika's effects hard to detect on ultrasound, MRI

By Brian Casey, AuntMinnie.com staff writer

February 5, 2018 -- A new animal study published February 5 in Nature Medicineillustrates the challenges in detecting how the Zika virus affects the fetuses of infected mothers. Researchers found that the Zika virus caused injury to the brains of fetal macaque monkeys that was hard to detect with ultrasound and even MRI.

Zika sent chills throughout tropical regions when cases began appearing frequently in 2016, with Brazil being hit particularly hard. Most often spread by mosquitoes, the disease caused conditions such as microcephaly in infants born to infected mothers. While the outbreak has subsided since then, healthcare providers and public health authorities are keeping a watchful eye for its resurgence.

In the new paper, researchers from multiple centers described their efforts to detect the signs of Zika damage in the brains of fetuses by using tools including ultrasound and MRI (Nat Med, February 5, 2018). Knowledge of these signs could help providers counsel pregnant women with Zika infection, in particular for infants who are infected with the virus but who don't have the telltale signs of microcephaly.

The researchers infected a test group of five pregnant pigtail macaque monkeys, while a control group of animals remained uninfected. They followed the symptoms that emerged after infection and performed regular imaging studies with ultrasound and MRI, in addition to using blood tests and other exams to track the progress of the monkeys and their fetuses.

Weekly ultrasound scans detected no obvious fetal abnormalities except for a periventricular echogenic lesion and ventriculomegaly in one monkey, the group found. Likewise, Doppler ultrasound scans of the middle cerebral artery in the fetuses showed no differences in the resistance index, which the researchers took to mean that fetal brain oxygenation was the same between the infected and control monkeys.

One imaging tool that did work was MRI with a half-Fourier acquisition single-shot turbo spin-echo (HASTE) T2-weighted protocol. The technique revealed periventricular subcortical T2-hyperintense foci in the posterior brain in four of the five animals at 120 to 129 days of gestation, signs that were not found in the control fetuses. The brainstem and cerebellum otherwise appeared normal except for a cyst in one of the infected fetuses.

Researchers found telltale signs of Zika (periventricular subcortical T2-hyperintense foci in the posterior brain) on serial brain MRI scans with a HASTE protocol but said the phenomena were transient.

The study shows the difficulty in detecting signs of brain injury in fetuses carrying the Zika virus, the researchers concluded. While T2-hyperintense foci were detected by MRI, the phenomenon was transient, and in any event MRI is not widely available in many regions where Zika is prevalent.

"Our study highlights the inability of standard prenatal diagnostic tools to detect silent pathology in the fetal brain associated with congenital Zika infection in the absence of microcephaly," they wrote.

Low-risk thyroid nodules safe to track with ultrasound

By Kate Madden Yee, AuntMinnie.com staff writer

February 1, 2018 -- It's safe to use ultrasound to track thyroid nodules that don't have suspicious features after fine-needle aspiration (FNA) biopsy -- although nodules with intermediate or highly suspicious features should be evaluated with another biopsy, according to research in the February issue of the American Journal of Roentgenology.

The findings address disagreement among researchers regarding how to handle nondiagnostic nodules, defined as nodules that can't be classified as malignant or benign after FNA biopsy, wrote a team led by Dr. Chae Jung Park of Yonsei University College of Medicine in Seoul, South Korea. Some professional groups recommend repeat fine-needle aspiration biopsy if a nondiagnostic nodule is solid at ultrasound examination, while others say this isn't necessary.

"Some researchers suggest that clinical and ultrasound follow-up may be more appropriate than repeat fine-needle aspiration after nondiagnostic biopsy regardless of ultrasound features because few malignancies are diagnosed in this population," the study authors wrote. "The purposes of this study were to evaluate the malignancy rate of nodules with nondiagnostic cytologic results ... and to establish management guidelines for these nodules according to the ultrasound patterns."

Safe and reliable

Ultrasound-guided FNA biopsy is considered a safe, reliable, and cost-effective way to distinguish between benign and malignant thyroid nodules. But the procedure can produce a nondiagnostic result if the sample isn't adequate, the group wrote (AJR, February 2018, Vol. 210:2, pp. 412-417).

In 2015, the American Thyroid Association (ATA) recommended repeat FNA biopsy for initially nondiagnostic nodules and surgical confirmation for nodules with suspicious ultrasound features, along with continued close follow-up with ultrasound for repeatedly nondiagnostic nodules without suspicious ultrasound features.

However, these guidelines have not been confirmed, Park and colleagues wrote.

"To our knowledge, no validation studies have been conducted to assess these management guidelines according to the 2015 ATA ultrasound patterns," they wrote.

Park's group assessed 441 nodules larger than 1 cm found in 437 patients with nondiagnostic ultrasound results between January 2013 and December 2014. Of these 441 nodules, 191 were confirmed with cytopathology or were smaller than 3 mm at follow-up ultrasound. These 191 nodules made up the study sample.

The researchers classified the 191 nodules according to the ATA 2015 guidelines as high, intermediate, low, and very low suspicion for malignancy -- or benign. They used histopathologic confirmation as the reference standard.

Among the 191 nodules, 20 (10.5%) were malignant -- with a mean size of 17.4 mm -- and 171 (89.5%) were benign. Common features of these malignant nodules were solid composition, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and a taller-than-wide shape; the association of these features with malignancy was statistically significant (p < 0.001).

A total of 52 nodules (27.2%) were surgically confirmed; of these, 19 were malignant and 33 were benign. Seventy-seven nodules were evaluated with repeat FNA or core-needle biopsy.

Malignancy rate of nondiagnostic nodules based on ATA suspicion categories
ATA category	No. of nodules	Malignancy rate
Very low	58	0%
Low	45	0%
Intermediate	58	10.3%
High	30	46.7%

p > 0.001

"On the basis of an assessment of ultrasound features according to the ATA guidelines, we observed that the malignancy rate of nondiagnostic nodules increases substantially as the suspicion of malignancy increases," the team wrote. "None of the nodules that had very low or low suspicion of malignancy were confirmed as malignant."

Is ultrasound enough?

The study suggests that nodules with very low or low suspicion of malignancy can be followed up with ultrasound, the authors wrote. There were no malignancies in the 103 nodules that fit these classifications, and among the 77 nodules evaluated with repeat FNA or core-needle biopsy, 42.9% were considered to have low or very low suspicion of malignancy and could have been followed up with ultrasound instead.

"When ultrasound findings on thyroid nodules are assessed according to the 2015 ATA guidelines, nondiagnostic nodules with a very low- or low-suspicion ultrasound pattern can be followed up with ultrasound," Park and colleagues concluded. "Nondiagnostic nodules with intermediate or highly suspicious ultrasound patterns should be evaluated with repeat ultrasound-guided FNA."

FDA clears SuperSonic's Aixplorer for liver disease

By AuntMinnie.com staff writersFebruary 1, 2018

This clearance covers specific ultrasound imaging capabilities related to liver disease, and will allow clinicians to use Aixplorer to assess hepatic fibrosis and steatosis, the company said.

Aixplorer systems image and measure liver and spleen stiffness in real time under image guidance, using SuperSonic Imagine's shear-wave elastography technology. Liver and spleen stiffness are known to be correlated to liver fibrosis severity and are therefore considered key noninvasive markers of disease severity, according to the firm.