Prospective evaluation of acoustic radiation force impulse technology in the differentiation of thyroid nodules: accuracy and interobserver variability assessment.

PURPOSE: The aim of this study is to assess the diagnostic efficacy and interobserver agreement of acoustic radiation force impulse (ARFI) elasticity imaging in differentiating thyroid nodules. METHODS: In our study, 74 consecutive patients (52 females, 22 males; age range 27-77 years, mean: 41 years) with 82 thyroid nodules (60 benign nodules, and 22 malignant) were examined by two radiologists with different experience. Patients underwent either cytology using fine needle aspiration cytology or thyroid surgery. The diagnostic performance of the two operators at ARFI with sensitivity, specificity, positive predictive and negative predictive value, and ROC curves was estimated. Inter-reader variability between the two operators was defined using Cohen's k. RESULTS: According to receiver operating characteristics ROC curves (AUROC = 0.86 for observer 1; 0.81 for observer 2) sensitivity, specificity, PPV and NPV of reader 1 and 2 were respectively: 90, 75, 90.91 and 96.55 %; (cut-off value of shear wave: 2.455 m/s); 90, 72, 90 and 96.90 % (cut-off value shear wave: 2.365 m/s). Concordance between the two operators was good (k = 0.755). CONCLUSIONS: This work is a feasibility study evaluating ARFI imaging. Its results suggest that ARFI imaging is a reproducible method which can be utilized with good diagnostic performance in the thyroid for discriminating benign and malignant nodules using the cut-off value of 2.455 m/s. However, larger studies are needed to validate this method.

Ultrasound elastography in the evaluation of thyroid pathology. Current status.

Thyroid pathology including thyroid nodules and diffuse thyroid diseases represents often a diagnosing challenge for clinicians. US, although highly accurate in identifying thyroid nodules and diffuse thyroid diseases, is still not sufficiently accurate to evaluate them. US-elastography has been introduced in order to further increase US accuracy in many fields and eventually for thyroid disease. The aim of the present paper it to provide an update of the literature on different available techniques and the results reported both for thyroid nodules differentiation and for diffuse thyroid disease evaluation. Advantages and limitations of elastography are also discussed.

Clinical application of breast elastography: state of the art.

Breast elastography is a new sonographic imaging technique for the characterization of focal breast lesions in addition to conventional ultrasonography (US) and mammography. Elastography provides a non-invasive evaluation of the stiffness of a lesion. Two different technical approaches are available for clinical use: free-hand elastography (USE) and shear wave elastography (SWE). Initial results of these techniques in clinical trials suggest that elastography substantially improves the US capability in differentiating benign from malignant breast lesions, thus reducing the number of breast biopsies in benign nodules. This review paper, based on an extensive literature search, highlights the basics of breast elastography, including main technical features, how to do suggestions, limit and pitfalls, and presents the results of major clinical studies.

Metastatic signet ring cell carcinoma presenting as a thyroid diffuse involvement: report of a case studied with Q-elastographic and acoustic radiation force impulse imaging features.

Metastatic carcinomas to the thyroid are rare in daily clinical practice. However, when encountered they represent a diagnostic challenge, since it is difficult to distinguish them from primary thyroid lesions, especially when occurring in patients with occult malignant history. Nevertheless, it is critical to differentiate a metastatic tumor from primary thyroid lesions, as the clinical management and the prognosis are different for the two entities. More recently, elastosonography opened new possibilities to ultrasound in different fields, such as thyroid nodule differentiation. Herein, we report a case of metastatic signet ring cell carcinoma to the thyroid studied with quantitative elastography and acoustic radiation force impulse imaging.

Ultrasound evaluation of liver fibrosis: preliminary experience with acoustic structure quantification (ASQ) software.

PURPOSE: The aim of our study was to assess the diagnostic accuracy of acoustic structure quantification (ASQ) ultrasound software in estimating the degree of hepatic fibrosis compared to Fibroscan and liver biopsy. MATERIALS AND METHODS: Seventy-seven patients with chronic viral hepatitis B and C underwent standard ultrasound examination, ASQ, Fibroscan and liver biopsy. ASQ analysis was conducted by placing a single region of interest (ROI) on each image captured, and calculating mode, average and standard deviation. The sonographic technique was developed through a preliminary evaluation of 20 healthy volunteers. RESULTS: The area under the receiver operating characteristic (AUROC) curve for the diagnosis of cirrhosis (F≥4) with ASQ was 0.77, whereas for the diagnosis of any degree of fibrosis (F≥1) it was 0.71. The AUROC for the diagnosis of cirrhosis (F≥4) with Fibroscan was 0.98, while for the diagnosis of any degree of fibrosis (F≥1) it was 0.94. The difference between the AUROC was statistically significant (p<0.05). CONCLUSIONS: ASQ is a promising new ultrasound software programme which offers encouraging results in the diagnosis of both liver cirrhosis (F=4) and fibrosis (F≥1). However, to date it has not attained the same level of diagnostic performance as Fibroscan.

Prospective evaluation in 123 patients of strain ratio as provided by quantitative elastosonography and multiparametric ultrasound evaluation (ultrasound score) for the characterisation of thyroid nodules.

PURPOSE: This study was done to compare quantitative elastosonography and ultrasound analysis in the characterisation of thyroid nodules. MATERIALS AND METHODS: From July 2009 to September 2011, 123 patients with 147 thyroid nodules were included in our study. All patients enrolled had to undergo thyroidectomy because of nodular thyroid disease (goitre or nodules). After preliminary examination with conventional ultrasound (US) and colour Doppler US, the patients were examined with elastosonography, using high-level equipment (Toshiba Aplio XG) and quantitative software (Elasto-Q). Each lesion was characterised using an US score (echogenicity, borders, microcalcifications and colour Doppler pattern), and then by elastosonographic strain ratio. Each patient subsequently underwent thyroidectomy. Histological results were used as the gold standard. RESULTS: Histological examination demonstrated 89 benign and 58 malignant lesions. On average, the strain ratio value was 2.84±2.69 (range, 0.05-14.5; p=0.001). Sensitivity and specificity of the US score were about 56% and 72%, respectively, whereas those of the strain ratio were 93% and 89%, using a cut-off of 2 obtained with receiver operating characteristic (ROC) curve analysis. Elastosonography was more accurate than US and colour Doppler US in characterising thyroid nodules (p=0.002). CONCLUSIONS: Quantitative elastosonography is a useful diagnostic tool in the evaluation of thyroid lesions, and can be used to limit fine-needle aspiration cytology and improve the selection of patients for thyroidectomy.

Beyond laparoscopy: 3-T magnetic resonance imaging in the evaluation of posterior cul-de-sac obliteration.

OBJECTIVES: Endometriosis is the ectopic localization of endometrial glands. Symptoms include a wide variety of chronic pelvic pain. Ovarian endometriosis represents the most frequent site of implantation followed by the Douglas pouch which is undepicted unless peritoneal fluid is present. Pelvic exams may be reported as normal in 40% of evaluations, although multiple nodularities are located in this region. Nowadays, laparoscopy represents the standard technique for endometriosis evaluation. However, magnetic resonance imaging (MRI) remains the best noninvasive technique for the evaluation of pelvic lesions. According to the importance of a precise preoperative diagnosis of deep infiltrative endometriosis involving the Douglas pouch, we evaluated feasibility of a 3-T system in the evaluation of this particular region. METHODS: We enrolled 19 women coming with either ultrasound or anamnestic suspicion of endometriosis. Pelvic MRI examination was performed on the 3-T system. We applied a standard exam protocol including pulse sequences [single-shot fast spin echo (FSE)] and high-resolution T2W and T1W FSE sequences with and without FS. RESULTS: MRI diagnosed posterior cul-de-sac obliteration in 15/19 patients. MRI findings were compared with laparoscopy, thus obtaining the following statistical values: mean sensitivity, specificity, positive predictive value and negative predictive value, respectively, of 93%, 75%, 93% and 75%. Moreover, we calculated an interobserver agreement k value of 0.72 with a substantial degree of agreement between two radiologists of a sensitivity value of 93% and specificity value of 75%. CONCLUSIONS: Precise preoperative mapping of posterior cul-de-sac region is essential for a preoperative planning. In our work, the 3-T MRI was shown to be excellent in the evaluation of posterior cul-de-sac obliteration associated to an optimal evaluation of the uterosacral ligaments due to the higher contrast spatial resolution.