Comparative US-MRI evaluation of the Insall-Salvati index.

PURPOSE: To investigate whether the universally accepted range of normal patellar height ratio derived from MRI for the Insall-Salvati (IS) method could be similarly applied to ultrasound (US). MATERIALS AND METHODS: This study included 52 patients (age range 11-75 years) who underwent a bi-modality (US and MRI) examination, with a total of 60 knees evaluated. IS index (ratio of the patella tendon length to length of the patella) was acquired with both methods. Two operators, with different experiences of musculoskeletal imaging and blinded to the results of other investigators, separately performed the MRI and US measurements. RESULTS: For the two operators, MRI reported a mean value of patellar height ratio of 1.10 ± 0.16 (mean ± standard deviation SD), while US a mean value of 1.17 ± 0.16 (mean ± SD). For comparable results, the small addition of 0.16 is needed for the measurements on US compared with MRI. Inter-observer agreements using intra-class correlation coefficient (ICC) was, respectively, 0.97 for MRI and 0.98 for US. The difference of mean values in patellar height ratios between MRI and US was not statistically significant (p = 0.15). The ICC between the two modalities was 0.94. CONCLUSION: According to our experience, IS index can be appropriately evaluated on US images, reducing the need of other imaging techniques.

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.

Prospective evaluation of multiparametric ultrasound and quantitative elastosonography in the differential diagnosis of benign and malignant thyroid nodules: preliminary experience.

PURPOSE: To assess the clinical value of quantitative elastosonography compared with multiparametric ultrasound in differentiating the nature of thyroid nodules. METHODS AND MATERIALS: Ninety-seven consecutive patients (32 males, 65 females, mean age, 54 years, range 20-81 years) with thyroid nodules previously detected at color-Doppler ultrasound (CDUS), were prospectively examined with elastosonography with dedicated quantitative software (Elasto-Q, Toshiba) before surgery. Ultrasound examination and elastosonography were evaluated by two investigators in consensus. US features, color-Doppler pattern, and strain ratio value were evaluated. Sensitivity and specificity of CDUS and sono-elastography were compared using X(2) test and ROC curves. RESULTS: Sensitivity and specificity of hypoechogenicity, irregular margins or suspicious halo features, CDUS blood flow pattern, and strain ratio in the diagnosis of malignant nodules were 56.8%, 62.2%, 54.1% and 97.3% and 71.7%, 93.3%, 28.3%, and 91.7%, respectively. Elastosonography was more sensitive and specific than all ultrasonographic features in predicting malignancy of the thyroid nodules (p<0.0001). According to elastosonographic features the lesions characterized by strain ratio ≥ 2 were highly likely to be of malignant nature (p<0.0001, O.R. 396, 95%, CI: 44-3530). CONCLUSIONS: The results of the present study suggest that elastosonography with Q system is a valuable tool in the characterization of thyroid nodules and it seems to be far more accurate than CDUS. These findings as well as those of previous studies support its use in selecting patients who are candidates for surgery.