Real-time Ultrasound Elastography Research Articles

Assessment of Carotid Arterial Wall Elasticity in Type 2 Diabetes Mellitus Patients with Microalbuminuria by Real-Time Ultrasound Elastography

The aim of this study was to evaluate carotid arterial wall elasticity in type 2 diabetes mellitus (T2DM) with microalbuminuria by real-time ultrasound elastography. Two hundred and ten T2DM patients were divided into two groups according to levels of urinary albumin excretion (UAE): T2DM without microalbuminuria (T2DM1 group, 120) and T2DM with microalbuminuria (T2DM2 group, 90). The right common carotid arteries were examined by real-time ultrasound elastography. The strain ratio (SR, blood to arterial wall strain ratio) was calculated by dividing the strain value of the blood by that of the carotid arterial wall. The correlation between SR and general data was analyzed. The mean SR value ± SD of T2DM2 group was significantly higher than that of T2DM1 group (P < 0.05). SR was positively and significantly correlated with UAE, HbA1c, and systolic blood pressure (r = 0.456,0.435,0.235, P < 0.05 for all). The mean value ± SD of UAE, HbA1c, 2hPG, BMI, and TC of T2DM2 group was significantly higher than that of T2DM1 group (P < 0.05 for all). In conclusion, there is an association between microalbuminuria and carotid arterial wall elasticity in T2DM patients.

Shear Wave Elasticity Imaging of Cervical Lymph Nodes

A pilot study of real-time shear wave ultrasound elastography (SWE) for cervical lymphadenopathy in routine clinical practice was conducted on 55 nodes undergoing conventional ultrasound (US) with US-guided needle aspiration for cytology. Elastic moduli of stiffest regions in nodes were measured on colour-coded elastograms, which were correlated with cytology. Malignant nodes (n = 31, 56.4%) were stiffer (median 25.0 kPa, range 6.9–278.9 kPa) than benign nodes (median 21.4 kPa, range 8.9–30.2 kPa) (p = 0.008, Mann Whitney U test). A cut-off of 30.2 kPa attained highest accuracy of 61.8%, corresponding to 41.9% sensitivity, 100% specificity and 0.77 area under the receiver operating characteristic curve. Qualitatively, elastograms of benign nodes were homogeneously soft; malignant nodes were homogeneously soft or markedly heterogeneous with some including regions lacking elasticity signal. SWE is feasible for neck nodes. It appears unsuitable for cancer screening but may detect a subset of malignant nodes. The cause of spatial heterogeneity of malignant nodes on SWE is yet to be established.

Efficacy of an Artificial Neural Network–Based Approach to Endoscopic Ultrasound Elastography in Diagnosis of Focal Pancreatic Masses

By using strain assessment, real-time endoscopic ultrasound (EUS) elastography provides additional information about a lesion's characteristics in the pancreas. We assessed the accuracy of real-time EUS elastography in focal pancreatic lesions using computer-aided diagnosis by artificial neural network analysis. We performed a prospective, blinded, multicentric study at of 258 patients (774 recordings from EUS elastography) who were diagnosed with chronic pancreatitis (n = 47) or pancreatic adenocarcinoma (n = 211) from 13 tertiary academic medical centers in Europe (the European EUS Elastography Multicentric Study Group). We used postprocessing software analysis to compute individual frames of elastography movies recorded by retrieving hue histogram data from a dynamic sequence of EUS elastography into a numeric matrix. The data then were analyzed in an extended neural network analysis, to automatically differentiate benign from malignant patterns. The neural computing approach had 91.14% training accuracy (95% confidence interval [CI], 89.87%-92.42%) and 84.27% testing accuracy (95% CI, 83.09%-85.44%). These results were obtained using the 10-fold cross-validation technique. The statistical analysis of the classification process showed a sensitivity of 87.59%, a specificity of 82.94%, a positive predictive value of 96.25%, and a negative predictive value of 57.22%. Moreover, the corresponding area under the receiver operating characteristic curve was 0.94 (95% CI, 0.91%-0.97%), which was significantly higher than the values obtained by simple mean hue histogram analysis, for which the area under the receiver operating characteristic was 0.85. Use of the artificial intelligence methodology via artificial neural networks supports the medical decision process, providing fast and accurate diagnoses.

Real-time elastography for the differentiation of benign and malignant breast lesions: a meta-analysis

The prognostic significance of ultrasound real-time elastography (RTE) in patients with breast lesions is controversial. There are two different diagnostic methods: the elasticity score (ES) and the strain ratio (SR). A meta-analysis was performed using a random-effect model to assess the overall sensitivity and specificity of RTE in the differentiation of breast lesions. MEDLINE, EMBASE, PubMed, and the Cochrane Library before February 2011 were searched. A total of 22 studies, which included 4,713 breast nodules in 4,266 patients were analyzed. The overall mean sensitivity and specificity for the diagnosis of malignant breast lesions by RTE were 0.834 [95% confidence interval (CI) 0.814-0.853] and 0.842 (95% CI, 0.829-0.854) for ES, and 0.883 (95% CI, 0.844-0.916) and 0.814 (95% CI, 0.786-0.839) for SR, respectively. RTE has a high sensitivity and specificity in the evaluation of breast lesions and can potentially reduce unnecessary breast biopsies.

Evaluation of tomosynthesis elastography in a breast-mimicking phantom

ObjectiveTo evaluate whether measurement of strain under static compression in tomosynthesis of a breast-mimicking phantom can be used to distinguish tumor-simulating lesions of different elasticities and to compare the results to values predicted by rheometric analysis as well as results of ultrasound elastography. Materials and methodsWe prepared three soft breast-mimicking phantoms containing simulated tumors of different elasticities. The phantoms were imaged using a wide angle tomosynthesis system with increasing compression settings ranging from 0N to 105N in steps of 15N. Strain of the inclusions was measured in two planes using a commercially available mammography workstation. The elasticity of the phantom matrix and inclusion material was determined by rheometric analysis. Ultrasound elastography of the inclusions was performed using two different ultrasound elastography algorithms. ResultsStrain at maximal compression was 24.4%/24.5% in plane 1/plane 2, respectively, for the soft inclusion, 19.6%/16.9% for the intermediate inclusion, and 6.0%/10.2% for the firm inclusion. The strain ratios predicted by rheometrical testing were 0.41, 0.83 and 1.26 for the soft, intermediate, and firm inclusions, respectively. The strain ratios obtained for the soft, intermediate, and firm inclusions were 0.72±0.13, 1.02±0.21 and 2.67±1.70, respectively for tomosynthesis elastography, 0.91, 1.64 and 2.07, respectively, for ultrasound tissue strain imaging, and 0.97, 2.06 and 2.37, respectively, for ultrasound real-time elastography. ConclusionsDifferentiation of tumor-simulating inclusions by elasticity in a breast mimicking phantom may be possible by measuring strain in tomosynthesis. This method may be useful for assessing elasticity of breast lesions tomosynthesis of the breast.

Preliminary application of ultrasound real-time elastography in diagnosis of thyroid diffuse disease

Objective To explore the diagnosis value of ultrasound real-time elastography in thyroid diffuse diseases.Methods Eleven elastic quantitative parameters of 123 patients with thyroid diffuse diseases and 42 healthy volunteers obtained from the ultrasound real-time elastography were analyzed with principal components analysis to attain a comprehensive evaluation value which was named stiffness index(SI),reflecting the organization elastic information of different thyroid diffuse diseases.SI among each group was compared by ANOVA.Results Chronic lymphocytic thyroiditis SI was 86.37±20.45,subacute thyroiditis SI was 86.14±19.95,primary hyperthyroidism SI was 54.68±21.69,normal control group SI was 41.34±15.59,respectively.The SI between chronic lymphocytic thyroiditis,subacute thyroiditis,primary hyperthyroidism and normal controls had significant statistical differences (P 0.05).Conclusions Ultrasound real-time elastography could indirectly reflect the stiffness information of thyroid lension tissue and have a certain degree of diagnosis value in thyroid diffuse disease. Key words: Ultrasonography; Thyroid diseases; Elasticity

Real‐time ultrasound elastography in the diagnosis and differential diagnosis of subacute thyroiditis

To assess the value of real-time sonographic (US) elastography in the diagnosis of subacute thyroiditis (SAT). This study included 29 lesions from 20 patients with SAT, 33 nodules from 24 patients with multinodular goiter, and 27 nodules from 23 patients with thyroid cancer. Eighty-nine lesions in these patients were examined by grayscale US and real-time US elastography. An elasticity score (ES), based on four classes of tissue stiffness (class 1 for soft lesions; class 2 and 3 for lesions intermediate in stiffness; class 4 for inelastic lesions), was introduced. The distribution of ESs for SAT and multinodular goiter or thyroid cancer was compared. Also, the correlation between serum-free thyroxine (FT4) concentrations and ESs for lesions in patients with SAT was analyzed. Nineteen of 29 SAT lesions had an ES of 3; the rest had an ES of 4. Of 33 multinodular goiter nodules, 5 had an ES of 1, 23 had an ES of 2, and 5 had an ES of 3. Eleven of 27 malignant thyroid nodules had an ES of 3; 15 had an ES of 4, and 1 had an ES of 2. In the distribution of ESs, there was a statistically significant difference between SAT lesions and multinodular goiter nodules (p < 0.05), but there was no significant difference between SAT lesions and malignant nodules (p > 0.05). No correlation existed between serum FT4 concentrations and ESs for the lesions in patients with SAT (p > 0.05). Real-time US elastography does not provide conclusive information in the diagnosis and differential diagnosis of SAT due to its inability to distinguish between SAT and thyroid cancer.

Value of two-dimensional,color Doppler ultrasound and real-time ultrasound elastography in diagnosing of Hashimoto's thyroiditis

Objective To investigate the different roles of two-dimensional,color Doppler ultrasound and real-time ultrasound elastography in the diagnosis of Hashimoto's thyroiditis(HT).Methods One hundred and forty-one patients clinically diagnosed as HT underwent traditional ultrasound and elastography.The patients were classified into three groups,the hyperthyroidism group,the hypothyroidism group and the euthyroidism group.One hundred and eight volunteers with normal thyroid functions were enrolled as control group.Ultrasonic characteristics (size,echo,accompanied nodules,blood flow distribution of thyroid) and thyroid elastic parameters were recorded and analyzed.Results ①Focal hypoechoic pattern was mainly seen in the group of HT hyperthyroidim,diffuse hypoechoic pattern was mainly seen in the groups of HT euthyroidism,diffuse hypoechoic pattern with heterogeneous linear hyperechoic and nodular changes were mainly seen in the HT hypothyroidism group.②Blood flow reduced according to the order by the hyperthyroidim group,euthyroidism group and hypothyroidism group.③Patients with HT hyperthyroidism had elastic image pattern Ⅰ.Patients with HT euthyroidism had pattern Ⅰ and pattern Ⅱ.Patients with HT hypothyroidism had pattern Ⅱ and pattern Ⅲ.④There were significant differences (P＜0.05) between the mean elastic strain and the ratio of the blue area in each group.Conclusions Real-time ultrasound elastography is helpful for the diagnosis of HT. Key words: Ultrasonography; Hashimoto disease; Elastography

Cystic change in thyroid nodules: A confounding factor for real-time qualitative thyroid ultrasound elastography

To evaluate real-time qualitative ultrasound elastography for focal thyroid masses undergoing fine-needle aspiration in a routine thyroid ultrasound clinic. Ninety-four thyroid nodules scheduled for fine-needle aspiration cytology in a thyroid ultrasound clinic also underwent real-time freehand elastography. Colour-scaled elastograms were graded visually on the stiffness of the solid component of nodules relative to thyroid parenchyma using an elastography score (ES) scale from 1 (soft) to 4(stiff). The ES for benign and malignant nodules and the influence of cystic change on ES were analysed using Chi-square with trend and Fishers exact tests, with a p<0.05 used to indicate statistical significance. There were 19 papillary carcinomas, five metastases, 57 hyperplastic nodules, and four follicular adenomas based on definitive cytology (n=54) or histology (n=31). Nine nodules were excluded due to indeterminate cytology and no histology. Of malignancies (allsolid), two were ES=1, four were ES=2, eight were ES=3, and 10 were ES=4. Of benign nodules, 17 were ES=1, 17 were ES=2, 16 were ES=3, and 11 were ES=4. An ES>2 was more common in benign nodules with predominant cystic components (17/18) than mildly cystic (3/12) or completely solid (7/31) benign nodules (p=0.0004, p<0.0001). The ES was not significantly different between benign and malignant nodules (p=0.09) unless partially cystic nodules were excluded (p=0.005). For solid nodules, an ES>2 optimally predicted malignancy, achieving 74% sensitivity, 77% specificity, and 76% accuracy. Qualitative real-time thyroid elastography predicts malignancy only if predominantly cystic nodules are excluded, which may limit its utility in routine clinical practice.

Real-time quasi-static ultrasound elastography.

Ultrasound elastography is a technique used for clinical imaging of tissue stiffness with a conventional ultrasound machine. It was first proposed two decades ago, but active research continues in this area to the present day. Numerous clinical applications have been investigated, mostly related to cancer imaging, and though these have yet to prove conclusive, the technique has seen increasing commercial and clinical interest. This paper presents a review of the most widely adopted, non-quantitative, techniques focusing on technical innovations rather than clinical applications. The review is not intended to be exhaustive, concentrating instead on placing the various techniques in context according to the authors' perspective of the field.

Real-Time Qualitative Ultrasound Elastography of Cervical Lymph Nodes in Routine Clinical Practice: Interobserver Agreement and Correlation with Malignancy

To evaluate real-time qualitative ultrasound (US) elastography for cervical lymphadenopathy in routine clinical practice, 74 nodes (37 malignant, 37 benign) in 74 patients undergoing sonography underwent US elastography prior to fine needle aspiration for cytology. Dynamic cine loops of elasticity imaging displayed using a chromatic-scale were qualitatively scored by three independent observers for the proportion of stiff areas from ES1-4 (soft to stiff). There was fair to good interobserver agreement as indicated by weighted kappa (κ) statistic from 0.374 to 0.738. Median ES for benign and malignant nodes were 2 and 3 respectively. ES was higher in malignant nodes ( p = 0.0003–0.0049, Mann Whitney U tests) although areas under receiver operating characteristic curves (0.68–0.74) indicated suboptimal discrimination. The optimal discriminatory cut-off, ES > 2, achieved only 62.2% sensitivity, 83.8% specificity and 73% accuracy for malignancy. Improvements in reliability and accuracy of real-time qualitative ultrasound elastography are required for it to be adopted into routine clinical practice. (E-mail: aniltahuja@cuhk.edu.hk)

Real-Time Elastosonography: Useful Tool for Refining the Presurgical Diagnosis in Thyroid Nodules with Indeterminate or Nondiagnostic Cytology

Indeterminate and nondiagnostic patterns represent the main limitation of fine-needle aspiration (FNA) cytology of thyroid nodules, clinical and echographic features being poorly predictive of malignancy. The newly developed real-time ultrasound elastography (USE) has been previously applied to differentiate malignant from benign lesions. The aim of this study was to get further insights into the role of USE in the presurgical diagnosis of nodules with indeterminate or nondiagnostic cytology. The study included 176 patients who had one (n=138) or multiple (n=38) nodules with indeterminate or nondiagnostic cytology on FNA, for whom histology was available after thyroidectomy. A total of 195 nodules (142 indeterminate, 53 nondiagnostic) were submitted to USE, and elasticity was scored as 1 (high), 2 (intermediate), or 3 (low). In indeterminate lesions, the score 1, describing high elasticity, was strongly predictive of benignity, being found in 102 of 111 benign nodules and in only one of 31 carcinomas (P<0.0001). By combining the scores 2 and 3, USE had a sensitivity of 96.8% and a specificity of 91.8%. In nodules with nondiagnostic cytology, score 1 was found in 39 of 45 benign nodules and in only one of eight carcinomas (P<0.0001). By combining the scores 2 and 3, USE had a sensitivity of 87.5% and a specificity of 86.7%. USE may represent an important tool for the diagnosis of thyroid cancer in nodules with indeterminate or nondiagnostic cytology and may prove useful in selecting patients who are candidates for surgery.

Real-Time Qualitative Ultrasound Elastography of Miscellaneous Non-Nodal Neck Masses: Applications and Limitations

To evaluate real-time qualitative ultrasound elastography as an adjunct to conventional sonography for evaluation of non-nodal neck masses identified in routine clinical practice, 52 consecutive masses in 49 patients underwent both techniques. Lesion stiffness was graded visually on chromatic-scale elastograms from ES0-3 (low to high). Diagnosis was based on (cyto)pathology (11), corroborative cross-sectional imaging (18) or characteristic conventional sonography (23). There were 16 lipomas, 15 lymphatic/venous vascular malformations (LVVMs), six neurogenic tumours/neuromas, five thyroglossal duct cysts (TGCs), five (epi)dermoids, three abscesses, one second-arch branchial cleft cyst (BCC), and one soft-tissue metastasis. In general terms, lesion stiffness was high (ES2-3) for neurogenic tumours/neuromas, (epi)dermoids and metastasis, and low (ES0-1) for lipomas, LVVM, TGCs and BCC. Abscesses displayed variable stiffness according to fluid content. Technical limitations and artefacts of elastograms were identified. Data from real-time qualitative ultrasound elastography may be a useful adjunct to sonography for diagnosis of non-nodal neck masses (E-mail: aniltahuja@cuhk.edu.hk)

Evaluation of real-time qualitative sonoelastography of focal lesions in the parotid and submandibular glands: applications and limitations

To evaluate qualitative ultrasound elastography for focal salivary gland masses identified during routine clinical practice. Sixty-five parotid or submandibular masses in 61 patients underwent real-time qualitative ultrasound elastography and were scored on colour-scaled elastograms in terms of their stiffness relative to adjacent normal salivary parenchyma from ES 1 (soft) to ES 4 (stiff). This was correlated with diagnosis from aspiration cytology or histology. There were 29 Warthin's tumours (WTs), 23 pleomorphic adenomas (PAs), 2 adenoid cystic carcinomas, 1 adenosquamous carcinoma, 1 nodal metastasis from nasopharyngeal carcinoma, 1 lymphoma (2 deposits), 3 Kuttner tumours and 4 cases of Kimura's disease. ES scores showed clustering according to pathological condition. In this respect, PAs were firmer than WTs (P < 0.004, Fisher's exact test). Nine, 19, 14 and 17 of the benign masses and 0, 1, 2 and 3 of the malignant masses were ES 1, 2, 3 and 4 respectively. All three primary salivary malignancies were ES 4 compared with 1/29 WTs and 16/23 PAs. These preliminary findings suggest that qualitative real-time ultrasound elastography, although an ancillary technique to conventional ultrasound in the salivary glands, is likely to have a poor ability to discriminate benign lesions (particularly PAs) from malignant disease.

Differential Diagnosis of Small Single Solid Thyroid Nodules using Real-Time Ultrasound Elastography

In this prospective study, the diagnostic value of real-time ultrasound elastography (USE) was evaluated in 51 consecutive patients referred for surgical treatment with single solid thyroid nodules < 10 mm in maximum diameter with an indeterminate result on B-mode and colour Doppler ultrasonography. Ultrasonographic results were compared with histopathological data. Nineteen follicular adenomas and 32 papillary thyroid microcarcinomas (PTMCs) were observed. A real-time USE score of 4 - 5 diagnosed PTMCs with a sensitivity of 90.63%, a specificity of 89.47% and an accuracy of 90.20%. The positive and negative predictive values were 93.55% and 85.00%, respectively. It is concluded that real-time USE is a promising imaging technique that could assist in the differential diagnosis of single solid thyroid nodules < 10 mm in maximum diameter that give indeterminate results on conventional ultrasound.

Magnetic resonance imaging, ultrasound and real-time ultrasound elastography of the thigh muscles in congenital muscle dystrophy

Congenital muscle dystrophy includes a range of genetic disorders characterized by muscle weakness and contractures. We report the magnetic resonance (MR), ultrasound (US) and real-time sonoelastography (RTE) imaging findings of the thigh muscles of a 15-year-old boy with Bethlem myopathy diagnosed with clinical, electromyographic and histopathological criteria. Ultrasound and MR showed hyperechoic appearance and high signal intensity on T1- and T2-weighted sequences respectively at the periphery of the vastus lateralis and the long head of the biceps femoris muscles, and at a central area within the rectus femoris muscles. RTE was employed to examine the elastic properties of the muscle. The elastograms were presented as colour-coded maps superimposed on the B-mode images and revealed that the elastographic pattern correlated with the MR and US pattern of involvement. The abnormal muscle areas were stiffer (blue) than the normal-appearing areas (green), a finding that probably correlates with the presence of dystrophic collagen at the affected areas. This report suggests that RTE could be used as an additional imaging tool to evaluate the pattern of muscle changes in congenital myopathy. Further studies are needed to investigate the specificity and clinical value of RTE in the diagnosis and monitoring of neuromuscular disease.

Endosonographic elastography of the anal sphincter in patients with fecal incontinence

Objective. In fecal incontinence the role of elastography has not yet been evaluated. We performed a trial to further characterize the internal and external anal sphincter in patients with fecal incontinence and compared a visual assessment scale with a computerized program for quantifying elastic properties of the anal sphincter. Material and methods. Fifty consecutive patients with fecal incontinence were studied (n = 31 following lower anterior resection, n = 8 with Crohn's disease, n = 9 following colon surgery, n = 2 others). Elastogram color distribution within the sphincter representing elastic properties was quantified using a visual analog scale and an off-line computerized area calculation program. Results. The main finding was that the inner anal sphincter (IAS) differed significantly from the external anal sphincter (EAS) with regard to elastogram color distribution. There were no significant correlations with clinical and functional parameters. There was, however, a non-significant increase in the percentage of blue (hard) areas in the IAS in patients neoadjuvantly irradiated for rectal or cervical cancer compared to non-irradiated patients, which was accompanied by a significant decrease in the resting sphincter pressure (p < 0.009). Conclusions. The IAS, a smooth muscle, and the EAS, a striated muscle, have different elastogram color distributions, probably reflecting their different elastic properties. The absence of significant correlations with the major clinical and functional parameters suggests that in routine clinical practice ultrasound real-time elastography may not yield additional information in patients with fecal incontinence. There may be exceptions, particularly in irradiated patients.

Interobserver Agreement in Assessing the Sonographic and Elastographic Features of Malignant Thyroid Nodules

The objective of our study was to investigate interobserver agreement for the diagnosis of malignant thyroid nodules using conventional B-mode ultrasound and real-time freehand ultrasound elastography. Between December 2007 and February 2008, 45 patients (age range, 19-73 years; mean age +/- SD, 45.0 +/- 12.2 years) with 52 thyroid nodules were examined with conventional B-mode ultrasound and real-time freehand ultrasound elastography. All the patients were scheduled to undergo thyroid surgery because a thyroid nodule had been proven malignant on aspiration cytology. Three radiologists independently performed conventional ultrasound and elastography and analyzed the ultrasound images. Using conventional ultrasound, observers recorded the following information about nodular features: composition (solid, cystic, or mixed cystic-solid), echogenicity (hyperechoic, isoechoic, hypoechoic, or markedly hypoechoic), margin (well circumscribed, microlobulated, or irregular), calcification (negative [no calcifications]; microcalcification, macrocalcification, or mixed-type calcifications), and shape (parallel or nonparallel). Observers determined the Ueno classification and area ratio for each nodule using ultrasound elastography. Interobserver agreement was evaluated with Spearman's correlation analysis for all findings except the area ratio, for which Pearson's correlation analysis was used. A p < 0.05 was considered to indicate statistical significance. Statistically significant (p < 0.05) concordance among the three radiologists was found on conventional ultrasound for most features except echogenicity and margin of thyroid nodules. The highest value of concordance on conventional ultrasound was achieved for composition (Spearman's correlation coefficient, 0.70-1.00), followed by shape (0.48-0.79) and calcification (0.47-0.62). The least concordant findings on conventional ultrasound were nodular echogenicity (0.04-0.45) and margin (0.03-0.29). However, there was no statistically significant concordance on elastography for the Ueno classification (Spearman's correlation coefficient, 0.08-0.22; p > 0.05) or the area ratio (Pearson's correlation coefficient, -0.03 to 0.23; p > 0.05). Statistically significant concordance among radiologists about most features of malignant thyroid nodules was seen with conventional ultrasound; however, ultrasound elastography did not show reliable interobserver agreement for the diagnosis of malignant thyroid nodules.

Real-time ultrasound elastography of the normal Achilles tendon: reproducibility and pattern description

To investigate the feasibility and reproducibility of real-time freehand ultrasound elastography (RTE) of the normal Achilles tendon and to describe its elastographic appearances. Fifty normal Achilles tendons were prospectively examined using RTE performed by tissue compression using the hand-held transducer. The information was colour-coded (red=soft, green=medium, blue=hard) and superimposed on the B-mode image. Each tendon was examined three times transversely and longitudinally by two radiologists and the ratio between tendon and retro-Achilles fat strain (strain index) was calculated. The reproducibility of the elastograms was assessed qualitatively and quantitatively using the strain index inter and intra observer variation coefficient (intra/inter-CV and intra/inter-CC, respectively). All tendons were clearly visualized on the elastograms. Nineteen tendons (19/50, 38%) appeared homogeneously green/blue (type 1). Thirty-one tendons (31/50, 62%) appeared green with longitudinal red stripes (type 2). The intra- and inter-CC values of the strain index were lower for the transverse plane than for the longitudinal plane (0.43, 0.45, 0.41 and 0.78, 0.66, 0.51, respectively). The intra-CV and inter-CV values were higher for the transverse than for the longitudinal plane measurements (39%, 37%, 30% and 30.50%, 30.10%, 29.60%, respectively). RTE of the normal Achilles tendon is a feasible method. The reproducibility of the strain index is good and higher for longitudinal elastograms. Qualitative assessment enables the discrimination of two distinct elastographic patterns. Further studies are required to assess the clinical value of this method.

Real-time Ultrasound Elastography in the Differential Diagnosis of Benign and Malignant Thyroid Nodules

The purpose of this study was to evaluate the diagnostic utility of real-time ultrasound elastography in differentiating benign from malignant thyroid nodules. A total of 90 consecutive patients with thyroid nodules who were referred for surgical treatment were examined in this prospective study. One hundred forty-five nodules in these patients were examined by B-mode ultrasound, color Doppler ultrasound, and ultrasound elastography. The final diagnosis was obtained from histologic findings. Tissue stiffness on ultrasound elastography was scored from 1 (low stiffness over the entire nodule) to 6 (high stiffness over the entire nodule and surrounding tissue). On real-time ultrasound elastography, 86 of 96 benign nodules (90%) had a score of 1 to 3, whereas 43 of 49 malignant nodules (88%) had a score of 4 to 6 (P <.001), with sensitivity of 88%, specificity of 90%, a positive predictive value of 81%, and a negative predictive value of 93%. The predictivity of ultrasound elastographic measurement was independent of the nodule size. High sensitivity (88%) and specificity (93%) were also observed in 68 nodules that had a greatest diameter of 1 cm or less. Real-time ultrasound elastography is a promising imaging technique that is useful in the differential diagnosis of thyroid cancer.