ARFI in DIFFERENTIATION of MALIGNANT from BENIGN THYROID NODULES with a cut-off value of Elastic V=2.545m/s

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Acoustic Radiation Force Impulse (ARFI) Imaging of Thyroid Nodules 

Vo Mai Khanh, Nguyen Thien Hung, Phan Thanh Hai 

MEDIC MEDICAL CENTER, HCMC, Vietnam

Purpose: The aim of the present study was to evaluate the feasibility of ARFI-measurements in combining of VTI in the thyroid nodule.

Methods and materials: All patients underwent conventional ultrasound, ARFI-imaging and cytological assessment. ARFI-imaging (VTI and VTQ technology) were performed with 9L4 probe, using Siemens (ACUSON S2000) B-mode-ARFI combination transducer. 

Results and Discussions: 130 nodules were available for analysis. 103 nodules were benign on cytology, 20 nodules were malignant (papillary carcinomas), and 7 follicular lesions. The average velocity of ARFI-imaging in benign and malignant thyroid nodules was of 2.4 m/s,  and of 3.2 m/s, respectively. A sensitivity of 79.4% and specificity  of 53.7% of ARFI-imaging could be achieved using a cut-off of 2.19 m/s (area under ROC curve is 0.731, p under  0.0001).
Conclusions: ARFI can be performed in thyroid nodule with reliable results. ARFI might be the reference criteria for differentiation of benign and malignant thyroid nodules. 

PURPOSES:

Acoustic radiation force impulse (ARFI) imaging is a novel ultrasound-based elastography method enabling quantitative measurement and qualitative assessment of tissue stiffness. In some recent studies, the feasibility of ARFI for evaluating the thyroid gland was shown. Most of those studies used VTQ (Virtual Touch Tissue Quantification) of ARFI-Imaging to measure the shear wave speed of tissue. However, the VTI (Virtual Touch Tissue Imaging) was still available, but it was subjective and dependent on the experience of the sonographer.

The aim of the present study was to evaluate the VTQ of normal thyroid tissues, benign and malignant thyroid nodules. Besides, VTI (Virtual Touch Tissue Imaging) of ARFI-Imaging was assessed in these objects as well.

MATERIALS AND METHODS:

A cross-sectional study was done from August 2011 to October 2012 at Medic Medical Center.  One hundred and thirty nodules  underwent conventional ultrasound, including Color Doppler ultrasound using a 7.5MHz linear transducer. Next, nodule stiffness were measured and assessed by VTQ and VTI of ARFI-Imaging (Acuson Siemens S2000).  The Region-of-interest (ROI) placed at the center of nodules and in the healthy thyroid gland away from thyroid nodules. In addition, five measurements were performed with the ROI for each nodule.  Exclusion criteria were “X.XX m/s” measurements. With VTI assessment, each nodule was assessed by 2 separate examiners. Afterward, FNAC (Fine needle aspiration cytology) under ultrasound guide was used as reference method for the diagnosis of benign and malignant thyroid nodules.

Statistical analysis was performed using Medcalc for Windows.

RESULTS:

Patient characteristics:

Age: 45 (range 16 – 69)

Size of nodule: 14mm (range 5 – 47mm)

Table 1: ARFI velocity characteristics:

ARFI velocity (m/s)	Normal thyroid	Benign nodule	Malignant nodule
Mean ± standard deviation	1.51 ± 0.07	2.15 ± 0.09	3.21 ± 0.46
Median	1.41	2.11	2.59
Minimum	0.84	0.80	0.90
Maximum	3.00	4.04	9.22

Figure 1: Receiver-operating characteristic (ROC) curve for VTQ values for diagnosis of benign and malignant thyroid nodules (AUROC 0.731, p under 0.0001).

Figure 2: Receiver-operating characteristic (ROC) curve for the difference of VTQ between normal thyroid tissue and thyroid nodule for diagnosis of benign and malignant thyroid nodules (AUROC 0.72, p under 0.0001)

Table 2:  Frequency table and Chi-square test for independence of VTI and the differentiation of benign and malignant nodules:

Codes X	VTI
Codes Y	FNAC

	Codes X
Codes Y	1	2	3	4
0	30	10	89	70	199 (76.5%)
1	51	1	4	5	61 (23.5%)
	81 (31.0%)	11 (4.2%)	93 (35.7%)	75 (29.1%)	260

Chi-square	102.553
DF	3

 Chi-square statistic = 102.553, predetermined alpha level of significance = 0.001,  degrees of freedom (DF=3), there is a relationship between VTI and the differentiation of benign and malignant thyroid nodules.

DISCUSSION:

-          The mean VTQ value of  benign thyroid nodules was higher than the one of normal thyroid tissue and lower than malignant thyroid nodules. It was reasonable because most of malignant nodules had harder stiffness than benign nodules.

-          However, the VTQ values were fluctuant and overlapped among these groups.  A malignant nodule was not completely solid, there were some necrosis regions inside it. Similar to benign nodule, some calcifications could make it become harder. Besides, the region of interest (ROI) of Acuson Siemens S2000 was rather big (D=6x5mm) and unadjustable. With some nodules were smaller than 6mm in size, the ROI could involve normal thyroid tissue in measuring VTQ. Anyhow, because AUROC was 0.731, VTQ of ARFI-Imaging could be considered as a helpful method in differentiating of benign and malignant thyroid nodules.

-           Some thyroid nodules combined with diffuse thyroid diseases (Basedow-Graves’ disease, chronic autoimmune thyroiditis,…) might influent to the result of VTQ. Recent study by Sporea I. et al, the stiffness of normal thyroid tissue was lower than in Graves’ disease and chronic autoimmune thyroiditis. In this study, we got VTQ values of thyroid tissue of the other lobe and measured the difference of VTQ values between thyroid nodule and thyroid tissue of the other lobe. The AUROC was 0.72, it meant the difference of VTQ between them would be considered to be “fairly good” at separating benign and malignant nodules. The harder nodule and the larger difference of VTQ between nodule and thyroid tissue of the other lobe were, the larger probability of malignant nodule was.

-          VTI was a qualitative variable therefore it depended on examiners. We had 2 examiners working separately and blinded with FNAC results. Each nodule had 2 evaluations in the classification (including 4  groups: dark, iso, bright and mixed color). The darker VTI was, the more malignant thyroid nodule was. The Chi-square test result showed a dependance between VTI and the differentiation of benign and malignant nodules, alpha level of significance = 0.001.

-          But this study existed some disadvantages:

+ This is a prospective study and FNAC was used as a reference method in differentiating benign and malignant nodules. As we all know, FNAC was not a gold standard of thyroid nodule’s diagnosis, histology was. But in our conditions of an out-patient clinic, it was impossible to have all postoperative results. Multicenters studies are awaited.

+ Our inclusion criteria was any size thyroid nodules detected by ultrasound. This might affect the VTQ result of Acuson Medison S2000 because of the big ROI. We suggested chosing nodules with > 10mm in size or waiting for another improvement of smaller ROI are.

+ The diffuse thyroid diseases combined thyroid nodules were popular, but in this study, they were not enough to do a statistical analysis. Larger studies are awaited.

ARFI RUỘT THỪA VIÊM @ MEDIC CENTER

Đến nay (02/2014) chúng tôi thu thập được 17 ca siêu âm đàn hồi ARFI ruột thừa viêm trước mổ trên máy ACUSON Siemens S2000, tất cả đều được chụp CT xác chẩn và phẫu thuật sau đó. Độ đàn hồi ARFI vách ruột thừa viêm= 2,715+/-0,325m/s trong khi độ đàn hồi vách ruột non lân cận =1,03+/-0,2m/s và mô mỡ mạc treo= 1,34+/-0,3m/s. Vách ruột thừa viêm cứng hơn ruột non không viêm và mô mỡ mạc treo.

Point-of-Care Ultrasound for Suspected Appendicitis in Children Deemed Effective Front-Line Tool

Point-of-Care Ultrasound for Suspected Appendicitis in Children Deemed Effective Front-Line Tool

By Medimaging International staff writers
Posted on 17 Feb 2014

Image: A recent study showed portable ultrasound used as a first-line imaging tool in children with suspected appendicitis helps cut emergency room length of stay and reduces the need for computed tomography (CT) scanning (Photo courtesy of James W. Tsung, M.D / Icahn School of Medicine at Mount Sinai).

Portable ultrasound used as a first-line imaging tool in children with suspected appendicitis helps cut emergency room length of stay and reduces the need for computed tomography (CT) scanning. Bedside ultrasound, also known to as point-of-care (POC) ultrasonography, has a specificity of about 94%, according to recent research.

The study’s findings were published online February 2014 in the journal Academic Emergency Medicine. “From an institutional perspective, this is the most common surgical problem that we encounter with children in the emergency department,” said the study’s senior author, James W. Tsung, MD, MPH, associate professor of emergency medicine and pediatrics at the Icahn School of Medicine at Mount Sinai (New York, NY, USA). “CT scans have been the best imaging test for diagnosing appendicitis, but they expose children to radiation, which cumulatively can prove harmful, as increasing numbers of studies have shown.”

Several studies have reported lifetime risks of cancer from abdominal and pelvis CT scanning in children results in one cancer death for every 500 to 3,000 CT scans ordered, depending on age and sex. Efforts to try to reduce the four million radiation-emitting CT scans obtained in children annually are underway, led by front-line radiologists, physicians, and radiologic professional societies. “CT scanning rate was reduced by over 35%, from a 44% CT scan rate prior to the study to a 27% rate during the study,” commented Ee Tay, MD, assistant professor of emergency medicine and pediatrics, Icahn School of Medicine at Mount Sinai, and the study’s second author.

Investigators, in their research, used a prospective observational sample of 150 children seen consecutively between May 1, 2011 and October 1, 2012 in an urban pediatric emergency department. All children were under evaluation for suspected appendicitis. Outcomes were determined by surgical or pathology report in those found to have appendicitis and three weeks later in patients who were considered not to have appendicitis. Operator accuracy reading the ultrasound scans was reviewed in a blinded fashion by trained pediatric emergency medicine sonologists. The time to perform the POC ultrasound and CT scan use was measured.

The study’s findings revealed that emergency department length of stay decreased by two hours and 14 minutes (46% decrease) for those requiring radiology department ultrasound and almost six hours (68% decrease) for those requiring CT scanning when POC ultrasound was inconclusive as a first-line imaging study. Significantly, no instances of appendicitis were overlooked with the POC ultrasound protocol and no needless surgeries were performed for a normal appendix. Pediatric emergency clinicians, with the use of focused ultrasound training, were able to assess ultrasound exams with the similar accuracy as radiologists (approximately 94% accuracy). Dr. Tsung noted, “Surgeons are becoming more comfortable using ultrasound for decision-making and that is a big change from reliance on CT scans.”

The Mt. Sinai division of emergency ultrasound is involved with an effort to educate providers to use safer ultrasound as a faster first-line study in children.

Related Links:
Icahn School of Medicine at Mount Sinai

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Canadian ob/gyns, rads target entertainment ultrasound

Canadian ob/gyns, rads target entertainment ultrasound
By Erik L. Ridley, AuntMinnie staff writer

February 20, 2014 -- The growing use of fetal ultrasound for nonmedical purposes has prompted two Canadian medical societies to issue a statement against the scans, which have been linked to gender-specific abortion in the country.


The Society of Obstetricians and Gynaecologists of Canada (SOGC) and the Canadian Association of Radiologists (CAR) issued a joint policy statement in the Journal of Obstetrics and Gynaecology Canada indicating their strong opposition to the nonmedical use of fetal ultrasound. The statement encouraged governments to join with them "to find appropriate means to deal with this public health issue."

Sex-selective abortion as a result of fetal ultrasound scans has long been a problem in developing countries such as India and China, where it has resulted in lopsided male-to-female ratios among the general population. But the problem is believed to be spreading to some developed countries such as Canada and the U.S. that have large immigrant communities.

The problem has been exacerbated by the rise of nonmedical ultrasound centers that offer "entertainment" scans, such as keepsake ultrasound images provided to expecting parents. Recent media coverage has highlighted the role of first-trimester gender determination by these centers in contributing to gender-specific abortion.

As a result, SOGC and CAR updated their individual policy statements on this issue with a new joint policy statement. The joint statement was prepared by the SOGC Diagnostic Imaging Committee and the CAR Point of Care Ultrasound Working Group, and it was approved by SOGC's executive council and CAR's board of directors (J Obstet Gynaecol Can, February 2014, Vol. 36:2, pp. 184-185).

While there is no definitive evidence that diagnostic ultrasound produces fetal abnormalities or harmful effects, studies of the biological effects of ultrasound in humans and in animal models indicate a theoretical risk, according to the organizations. For example, recent studies in animal models reported subtle effects on fetal brain physiology and development.

Nonmedical fetal ultrasound raises a number of safety concerns, according to the organizations.

"With the nonmedical use of fetal ultrasound, the maintenance of technical safeguards, operator training, qualifications, expertise, standards for infection control, and governing competency are no longer ensured," they said in the statement. "As a result, fetal energy exposure may not be appropriately monitored, and operators of the equipment may not be adequately trained to recognize fetal and placental abnormalities that may adversely affect fetal and maternal outcomes."

Other potential harms include false-positive diagnoses that lead to unnecessary investigations and anxiety, as well as false reassurance to the patient that everything is "normal," according to the organizations. Physical harm could also result if unsafe levels of abdominal pressure and fetal maneuvering are applied to obtain a suitable commercial product.

"The fetus should not be exposed to ultrasound for commercial and entertainment purposes, and it could be considered unethical to perform these scans," they wrote.

SOGC and CAR noted that both Health Canada and the U.S. Food and Drug Administration have recommended against the practice of commercial or entertainment ultrasound studies. Specifically, Health Canada recommends that ultrasound should not be performed in the following circumstances:

To take a picture of the fetus solely for nonmedical reasons
To learn the sex of the fetus solely for nonmedical reasons
For commercial purposes, such as the display of pictures or videos of a fetus at trade shows
"SOGC and CAR support the Health Canada recommendations and recommend that ultrasound be used prudently and only by qualified health professionals and that energy exposure be limited to the minimum that is medically necessary," according to the statement. "This technology should not be used for the sole purpose of determining fetal gender without a medical indication for that scan."

Related Reading
Report ties keepsake ultrasound to fetal gender tests in Canada, June 15, 2012

Toronto Star: Hospitals won't reveal baby's gender on US, April 18, 2012

AIUM: Keepsake US tied to low birth-gender ratios in Calif., April 3, 2012

Does keepsake ultrasound lead to gender abortions in Calif.?, March 30, 2010

Fetal entertainment ultrasounds draw patient interest, March 20, 2007


Copyright © 2014 AuntMinnie.com

Last Updated np 2/20/2014 11:45:14 AM
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MRElastography for Liver Diseae

Clinical Applications of Magnetic Resonance Elastography Growing

By Rob Goodier

 February 12, 2014

 

NEW YORK (Reuters Health) - Physicians have used Magnetic Resonance Elastography (MRE) to evaluate liver disease for the past five years, but a lengthening list of other applications for the imaging technology are coming on line, researchers say.

"I believe that the most likely application to be adopted next in clinical practice will be to use MRE to evaluate brain tumors preoperatively," Dr. Richard Ehman, a radiologist at Mayo Clinic and president and CEO of Resoundant Inc. in Rochester, Minnesota, told Reuters Health by email.

"Our preliminary experience is that MRE provides a reliable preoperative assessment of meningioma stiffness, which is extremely valuable information for surgical planning," Dr. Ehman said.

Dr. Ehman presented data from his work with MRE on February 4 at the American Society of Mechanical Engineering's third annual conference on Nanoengineering for Medicine and Biology in San Francisco, California.

Based on MR imaging, MRE gathers data from acoustic shear waves as they pass through and interact with the body. The result is maps showing the mechanical characteristics of the tissue - properties such as stiffness, viscosity, and anisotropy - or how its properties change from different angles.

Data from 4000 patients suggest that MRE is at least as accurate as liver biopsy for diagnosis of liver fibrosis, and it may be safer, more comfortable, and less expensive, Dr. Ehman wrote in conference materials.

Other applications under study include preoperative brain tumor analysis, analysis of the skeletal muscle, heart, and lungs, and diagnosis of breast and prostate cancer.

The findings are "very exceptional," said Dr. Jerry Lee, health sciences director at the U.S. National Cancer Institute, who attended the conference but is not involved in MRE research.

"I think it is a real life demonstration of how mechanical engineering theories are being applied to human disease right now," Dr. Lee told Reuters Health.

ULTRASOUND for ROUTINE LUMBAR PUNCTURE

Abstract

Objectives

The objective was to determine if use of ultrasound (US) by emergency physicians (EPs) to localize spinal landmarks improves the performance of lumbar puncture (LP).

Methods

This was a prospective, randomized, controlled study conducted in a county teaching hospital. Subjects, adults 18 years of age or older who were to receive LPs for routine clinical care in the emergency department (ED), were randomized either to undergo US localization of the puncture site or to have the puncture site determined by palpation of spinal landmarks. Primary outcomes were the number of needle insertion attempts and success of the procedure. Secondary outcomes were pain associated with the procedure, time to perform the procedure, number of traumatic taps, and patient satisfaction with the procedure.

Results

One-hundred patients were enrolled in the study, with 50 in each study group. There were no significant differences between the two groups in terms of age, sex, body mass index (BMI), indication for LP, or ease of palpation of landmarks. For both primary outcomes and secondary outcomes there were no significant differences between those undergoing US localization and those with palpation alone.

Conclusions

These data do not suggest any advantage to the routine use of US localization for LP insertion, although further study may be warranted to look for benefit in the difficult to palpate or obese patient subgroups.

Ultrasound accurate for appendicitis in children

Ultrasound accurate for appendicitis in children

By AuntMinnie.com staff writers

February 11, 2014 -- Portable ultrasound is an excellent first-line choice for diagnosing appendicitis in children, according to an article published online February 10 in Academic Emergency Medicine.

Bedside ultrasound delivered a specificity of 94% and reduced the need for CT scans by more than a third, according to study co-author Dr. Ee Tein Tay, assistant professor of emergency medicine and pediatrics at the Icahn School of Medicine at Mount Sinai.

CT is the most accurate imaging modality for diagnosing appendicitis, but it delivers a potentially harmful radiation dose, particularly in children. As a result, efforts are underway to reduce the 4 million radiation-emitting scans given to children each year.

The prospective, observational study included 150 pediatric patients who were evaluated for suspected appendicitis between May 2011 and October 2012 in an urban pediatric emergency department.

Use of portable ultrasound reduced the CT scanning rate by more than 35% -- from a 44% rate before the study to 27% during the study.

In addition, the emergency department length of stay declined 46% (by two hours and 14 minutes) for those undergoing radiology department ultrasound. Length of stay decreased by 68% (almost six hours) for those who required CT after an initial point-of-care ultrasound was inconclusive.

No cases of appendicitis were missed with the use of first-line ultrasound, and no unnecessary surgeries were performed for a normal appendix.

Related Reading

AJR: Using ultrasound 1st for appendicitis saves money, January 14, 2014

Study: Use ultrasound 1st for appendicitis in kids, December 3, 2013

Teleradiology on mobile devices OK for appendicitis, November 4, 2013

ARRS: MRI tops US in appendicitis detection in pregnant women, April 22, 2013

MRI helps guide appendicitis assessment in pregnant women, April 2, 2013

Copyright © 2014 AuntMinnie.com

Last Updated np 2/10/2014 5:41:54 PM

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SHEAR WAVE ELASTOGRAPHY of LIVER FIBROSIS

Sonography is a noninvasive and inexpensive procedure for diagnosis of diffuse liver disease; however, the value of sonography for distinguishing a low degree of liver fibrosis from cirrhosis is limited. In a study by Colli et al, 28 of 107 patients with severe fibrosis or definite cirrhosis (26%) had negative results for liver surface nodularity and caudate lobe hypertrophy and had normal hepatic venous flow. In this regard, elastography integrated into ultrasound systems is an effective adjunctive tool for quantifying liverfibrosis.

Conclusions

In patients with chronic viral hepatitis, particularly in patients with hepatitis C virus infection, all noninvasive methods are ready to be used for detecting and staging liver fibrosis before therapy at a safe level of predictability.

As with transient elastography, elastographic techniques based on shear waves generated by the acoustic beam are more accurate in detecting cirrhosis than significant fibrosis. They have the advantage of B-mode guidance, which allows one to choose an area of liver parenchyma better suited for stiffness assessment (ie, free of large vessels and focal lesions).

These methods are all valid when information about fibrosis is needed. Liver biopsy should still be performed when biochemical tests and imaging studies are inconclusive or information other than liver fibrosis is required.