The role of sonoelastography in the differential diagnosis of neck nodules

Abstract

KEYWORDSTechnology assessment; Thyroid; Tumor.Abstract Sonoelastography is an imaging technique that provides information on tissue elasticity. Its use as a diagnostic procedure is based on the premise that pathological processes like cancer alter the physical characteristics of the involved tissue. Ultrasonographic studies of the neck can reveal the nonpalpable thyroid nodules, but the nature of these lesions generally has to be established on the basis of FNAB findings. In our hands, sonoelastography displayed a diagnostic accuracy of 86.2% in identifying thyroid nodule malignancy, with positive and negative predictive values (PPV and NPV) of 64% and 94.5%, respectively. In the study of cervical lymph nodes, the results were less impressive (sensitivity 75%, specificity 80%, accuracy 77%, PPV 80%, NPV 70%), but the information obtained with this technique can in our opinion be a useful adjunct to sonographic findings. Indeed, in 5 lymph nodes with sonographic features consistent with malignancy, sonoelastography revealed diffuse elasticity that was indicative of benign disease, which was confirmed by pathological studies. Other nodular lesions of the neck can also be evaluated with sonoelastography, including enlarged parotid glands, but the data in the literature are too limited to allow hypotheses on the role of this imaging modality in this field. Sonoelastography is rapid and simple to perform, and it appears to be a potentially useful tool for the differential diagnosis of neck nodules. This is particularly true of thyroid nodules. Our experience with these lesions indicates that diffuse elasticity is strongly correlated with benign disease. If this finding is confirmed in larger studies, sonoelastography might be used to identify thyroid nodules that do not require immediate biopsy.Sommario L'elastosonografia è una tecnica di imaging che fornisce informazioni relative alla elasticità dei tessuti e che può essere utilizzata nella pratica clinica basandosi sul presupposto che i processi patologici, come il cancro, inducono modificazioni della caratteristiche fisiche dei tessuti ammalati. Lo studio ecografico della loggia cervicale permette di individuare formazioni nodulari non palpabili all'interno della tiroide, tuttavia l'accuratezza diagnostica di questa tecnica è scarsa e per tale motivo il ricorso alla FNAB è spesso necessario. Nella nostra esperienza l'elastosonografia ha dimostrato, nella diagnosi differenziale dei nodi tiroidei, un'accuratezza diagnostica del 86,2% con VPN 94,5% e VPP 64%. Nello studio dei linfonodi cervicali i risultati ottenuti sono meno brillanti (sensibilità, specificità e accuratezza rispettivamente del 75%, 80% e 77% con VPP e VPN di 80% e 70%), ma riteniamo che le informazioni ottenibili possono in molti casi essere utili per integrare i dati ecografici; in particolare in 5 casi di linfonodi con caratteristiche morfo-strutturali indicative di malignità, l'elastosonografia ha dimostrato un pattern di completa elasticità, riconoscendo la natura benigna confermata dalle succes...

Impact of nodular size on the predictive values of gray-scale, color-Doppler ultrasound, and sonoelastography for assessment of thyroid nodules

“…Recent studies demonstrated that ultrasoundbased elastography could improve detection of malignant thyroid nodules with a high sensitivity and good specificity (Lyshchik et al, 2005;Rago et al, 2007;Asteria et al, 2008;Dighe et al, 2008;Rubaltelli et al, 2009;Bojunga et al, 2010). In our study, the NPV of sonoelastography was 91% in SNs and 96% in LNs, which could be useful in determining which nodules could be safely observed without biopsy.…”

“…Pathologic changes are generally correlated with changes in tissue stiffness. Some benign nodules, such as subacute thyroiditis, nodules with coarse calcification or fibrosis, may have increased stiffness (Rago et al, 2007;Asteria et al, 2008;Hong et al, 2009;Rubaltelli et al, 2009;Bojunga et al, 2010). Thus, the false-positive results may increase, resulting in a specificity decrease.…”

“…Second, not all nodules are amenable to sonoelastography. Sonoelastography cannot be performed on nodules with peripheral rim calcification, nodules with a large cystic component, nodules with a diameter of <5 mm and coalescent nodules (Lyshchik et al, 2005;Rago et al, 2007;Asteria et al, 2008;Dighe et al, 2008;Hong et al, 2009;Rubaltelli et al, 2009;Bojunga et al, 2010;Kagoya et al, 2010). Third, the overall quality of sonoelastography is dramatically affected by the decorrelation noise caused by the out-of-plane motion of the examined lesion under compression and the pulsation of the carotid artery (Lyshchik et al, 2005;Asteria et al, 2008;Rubaltelli et al, 2009;Bojunga et al, 2010).…”

“…Preliminary results of sonoelastography have shown an excellent differentiation of variable hardness of thyroid nodules when compared to histopathology (Lyshchik et al, 2005;Rago et al, 2007;Asteria et al, 2008;Dighe et al, 2008;Rubaltelli et al, 2009;Bojunga et al, 2010). Whether elastographic measurement can give reliable results in nodules less than 10 mm is not clear.…”

Roles of gray-scale, Color-Doppler ultrasound and sonoelastography for assessment of thyroid nodules: nodule size correlation

“…Ultrasound features predictive of malignant nodules include the presence of irregular margins, marked hypoechogenicity, microcalcifications, taller-than-wide shape, intranodularvascularity (17,20,21,22,23,24). Ultrasound evaluation of the border of a thyroid nodule can be classified as well-defined or ill-defined.…”