ARDMS March 18, 2011 NewsWire‏

Pre-operative Ultrasound Scans Help Predict Outcomes of Thyroid Cancer Patients

Among other medical tests administered to patients with thyroid diseases, ultrasound scans of the neck may accurately predict a person's post-operative health outcomes, according to a new scientific investigation.

A study published in the journal Archives of Otolaryngology - Head and Neck Surgery found that scanning the neck compartments of patients treated for papillary thyroid cancer provided an accurate indication of a patient's six-year health outcomes.

Endocrinologists at the Universities of Arkansas and Texas came to this conclusion after examining the medical test data taken from more than 300 patients with papillary thyroid carcinomas over a 12-year period.

Papillary thyroid cancer is the most common variety of the disease. It constitutes at least 70 percent of all diagnosed cases of thyroid cancer, according to the Columbia University Department of Surgery. It is also the most treatable form of thyroid cancer.

Before surgery - which was typically a lateral neck dissection - the group of participants almost unilaterally had ultrasonographic scans performed on their necks. This is a non-invasive procedure designed to detect nodules in the lymph nodes and thyroid and salivary glands.

The outcomes of these scans were highly predictive of a patient's overall health over the next five to 10 years.

Those whose scans contained nodular abnormalities tended to see a reduction in their survival rates. The presence of an abnormality on ultrasound reduced the measured 10-year survival rate from more than 95 percent to 58 percent.

Overall, though, the rate of recurrence of papillary thyroid cancer was extremely low when surgery was prefaced with an ultrasound. The team found that the disease returned in just 0.3 percent of patients who'd had a pre-operative neck scan.

In the United States, nearly 45,000 people are diagnosed with some form of thyroid cancer every year, according to the National Cancer Institute.
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Article written by staff at endocrineweb.com and adapted for the purposes of this newsletter.

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Ultrasound Elastography Developments Lead to Increased Sensitivity of Malignant Nodes

Developments in ultrasonography, including ultrasound elastography, offer increased sensitivity for assessment of malignant nodes. Further, microbubbles were shown to reduce the need for completion axillary lymph node dissection (ALND) by 50 percent. These findings were presented at European Congress of Radiology 2011.

Ultrasound elastography used in conjunction with conventional ultrasound demonstrates axillary lymph nodes (ALNs) and differentiates benign from malignant nodes. The method also potentially increases sensitivity of identifying abnormal nodes for biopsy.

Dr. Kathryn Taylor, from Addenbrookes Hospital, Cambridge, UK, was the lead investigator on the study. Researchers looked at imaging modalities for preoperative assessment of axillary metastases in suspected breast cancer. Due to the relatively high false negative rate with conventional ultrasound plus needle biopsy, the researchers investigated the sensitivity of ultrasound elastography as an adjunct to conventional ultrasound.
Elastography is based on the principle that malignant tissue is stiffer than non-malignant tissue. A conventional ultrasound can be used with some additional software for the elastography. Taylor explained that some form of stress is applied to the tissue and any resulting tissue deformation is assessed, and an elastogram is displayed visually as a grey-scale (white is soft and dark is stiff tissue) or a color-scale (red is soft and blue is stiff).

“In terms of ALNs, the gold standard is conventional ultrasound +/- needle biopsy, which is performed as routine practice in women with routine breast cancer, but we know that this carries a false negative rate of up to 30 percent of nodes which show normal morphology but are metastatic,” said Taylor.

In this study, 50 women with suspected solid breast lesions received routine conventional ultrasound of ipsilateral ALNs followed by quasi-static ultrasound elastography using software from the University of Cambridge. “The ultrasound elastography was retrospectively scored one to four (blinded for histology) and compared to histology as reference standard,” Taylor said.

Results showed that adding ultrasound elastography to conventional ultrasound reduces the false positive rate from 44 percent to 19 percent. Twenty-seven were morphologically normal on conventional ultrasound of which five were malignant at surgical histology. Importantly, all five were suspicious/malignant (score 3/ 4) on ultrasound elastography. Adding ultrasound elastography to conventional ultrasound raises sensitivity by 24 percent.

“Of the 21 ultimately positive in histology, 15 were correctly identified by ultrasound elastography as positive, and an additional four from the conventional ultrasound arm. Remember this scenario, unlike that of elastography of breast lesions where we are more interested in specificity than sensitivity because we want to avoid unnecessary biopsy, in the axilla, within reason, we are more interested in sensitivity to avoid unnecessary surgical sentinel lymph node biopsy,” according to Taylor

The results showed sensitivity of ultrasound elastography of 90 percent and specificity of 86 percent.

At the same session on ultrasound developments, Dr. Ali Riza Sever from Maidstone Hosptial, UK, presented results from a study which evaluated use of microbubbles to identify involvement of the sentinel lymph node (SLN) compared to SLN biopsy with blue dye which is the standard procedure for axillary staging in early breast cancer.

Twenty-five percent of patients undergoing SLN biopsy currently require a second operation. This study looked at whether identification of SLNs with microbubbles would prevent or reduce the need for second operation.

“In order to validate our results with surgical results, we inserted a guide-wire into the enhancing lymph node preoperatively and correlated these nodes with the surgeons ‘hot’ and blue nodes. We showed that what we saw was the same as what a surgeon would have otherwise seen,” Sever said.

Following the successful validation phase they recruited 99 patients with proven invasive breast cancer who received microbubbles injected intradermally into the areola margin. SLNs were identified and biopsied preoperatively by contrast-enhanced ultrasonography.

Depending on the biopsy results, patients had either a conventional SLN biopsy or axillary lymph node dissection (ALND). In 97 cases, SLN was successfully identified. Eighteen of these were lymph node positive. Eleven of this group were proven node positive by using the microbubbles and were treated with immediate ALND whilst the remainder underwent conventional SLN biopsy with blue dye and isotope injection. “We reduced futile SLN procedures to 8 percent due to this microbubble procedure,” Sever said.

In conclusion, Sever said that microbubbles can identify the SLN, and when the enhanced lymph node is biopsied it is possible to reduce the completion ALND rates in more than 50 percent of the cases, however a negative biopsy result cannot omit the need of a conventional SLN biopsy.

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Article written by staff at diagonosticimaging.com and adapted for the purposes of this newsletter.

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The Trouble with Ultrasound's Pervasive Use by Non-Radiologist

Use of ultrasound by non-radiologists has shot up in recent years, for procedures and for diagnostics. Thanks to it being a safe, easy-to-use modality and the machines becoming increasingly smaller and more portable, clinicians ranging from trauma surgeons to cardiologists to anesthesiologists, are finding uses for ultrasound.

This is according to a recently published review article in the New England Journal of Medicine, “Point-of-Care Ultrasonography,” written by Christopher M. Moore, MD and Joshua Copel, MD, in conjunction with the November 2010 American Institute of Ultrasound in Medicine (AIUM) Practice Forum on point-of-care use of ultrasound. At the forum, 45 organizations came together to discuss and develop specialty-specific performance and training guidelines for the use of ultrasound. The AIUM continues to work with these groups on guidelines.

Point-of-care ultrasound is by definition more immediate and focused on a specific issue. “When ultrasound is performed in a radiology department, it’s a more complete, comprehensive study, referred by the patient’s physician to evaluate the patient’s symptoms,” said Harvey L. Nisenbaum MD, President of AIUM and a radiologist at the University of Pennsylvania. In “point-of-care ultrasound, the physician examines a patient and uses ultrasound as part of their physical exam to help diagnose the problem. It’s a different focus than the radiologist’s more complete examination.”
While its use is well-known in pregnancy, ultrasound is increasingly helpful in diverse specialties for both procedural guidance as well as diagnostic use. In procedures, ultrasound is used by clinicians to decrease complications and verify needle placement for anesthesia, biopsies, vascular access, thoracentesis, and abscess drainage. In terms of diagnostic use, doctors use it for focused exams of specific organs, trauma, or disease.

This recent article doesn’t uncover ground-breaking science, but it does “inform the medical community and lay people that this is an important modality, very pervasive,” said Nisenbaum.

Point-of-care ultrasound offers a trade-off between modality expertise and speed of diagnosis, according to Deborah Levine, MD, chair of the American College of Radiology (ACR) Ultrasound Commission and Professor of Radiology at Harvard Medical School. “Potentially it offers faster diagnosis, but not necessarily better diagnosis,” she said. “There’s a trade-off between knowing ultrasound and having the best equipment, and being the primary-care provider and using ultrasound.” She noted that radiologists have years of training in the modality, having studied proper use, the physics behind it, and differences in the various machines.
It’s great that ultrasound can offer more immediate results, Levine said, but those results only help if they’re accurate. “The threat of point-of-care ultrasound for patient care is if the machines aren’t good enough quality to answer the clinical question, if the anatomy isn’t understood, if artifacts aren’t understood, if anomalies are missed, and if there are false positive diagnoses that increase patient anxiety or add additional procedures,” she said.

No matter what specialty is using the modality, training is paramount, Nisenbaum and Levine said. In the early days of ultrasound, learning ultrasound was a matter of on-the-job training, said Levine. “Now ultrasound technologists have to go to school to learn about the machines, the anatomy, the physiology, and they have to take a test, so we know there’s a minimum standard for quality patient care.”

Not so for point-of-care ultrasonography.“With point-of-care ultrasound, it’s like you’re taking a huge step backwards, and you’re back to on-the-job training,” she said, adding that many clinicians using it think on-the-job training is fine, because they are doing very focused exams. “But all the pitfalls are still there. If you don’t have a minimum standard of training, things can get lost with on-the-job training.”

She suggests four main categories for minimum training in ultrasound for patient care: training, competence, continuing medical education, and quality assurance. Figuring out who is setting that minimum standard, however, is difficult.

"Who is making sure people using ultrasound have the appropriate training, understanding and competence to do the procedure correctly, and who is monitoring the quality of the exams?" said Dr. Levine

For quality assurance, Levine wants the point-of-care ultrasound images and reports to be available for viewing by other clinicians. “You want to make sure that images taken can be seen by anyone outside of where they’re taken, that they don’t disappear,” she said.

In a hospital, any treating clinician can access a patient’s radiology images. “With a lot of point-of-care ultrasound,” said Levine, “storing images and having them be part of the medical record is not part of the culture, and perhaps the infrastructure is not there.”