Assessment of parotid gland masses with B-mode ultrasonography and strain elastography findings

Abstract

Aim: Ultrasound elastography (USE) has been found useful in differentiation between malignant and benign lesions of various tissues, such as the thyroid, breast, lymph node and prostate, however, there is limited data on the parotid gland. The aim of this study is to assess the diagnostic performance of B-mode ultrasonography (US) and USE findings in differentiating between benign and malignant parotid gland masses. A secondary goal is to evaluate results for the most frequent benign lesions. 

Methods: In this cross-sectional study, 57 masses in 48 patients were evaluated. 2 radiologists examined each patient. B-mode US (size, contour, skin depth, internal structures, calcification, cystic component) and USE (a semiquantitative value strain index (SI)) findings were noted. We considered each feature individually. All patients underwent fine needle aspiration cytology (FNAC) and surgical resection.

Results: 50 masses were benign and 7 were malignant. Among B-mode US results, contour irregularity was found to have the highest accuracy (85.7%) in differentiating malignant lesions. When USE findings were considered, intra-observer agreement was moderate to fair and interobserver agreement was moderate. Malignant masses had mildly high SI scores. There was a wide range overlap between malignant and benign lesions. There was no statistically significant difference (P=0.422) and we could not attain a reliable SI cut-off value.

Conclusion: Despite the promising results of USE in breast and thyroid lesions, conventional US findings and FNAC are still the primary diagnostic tool to evaluate parotid lesions.

Keywords

• Ultrasound elastography,Strain elastography,Strain index,Parotid gland

Parotis bezi kitlelerinin B-mod ultrasonografi ve strain elastografi bulguları ile değerlendirilmesi

Abstract

Amaç: Ultrason elastografi (USE) tiroid, meme lenf nodu ve prostat dokularının benign ve malign lezyonlarının ayrımında kullanışlı bulunmuştur. Bununla birlikte parotis bezindeki kullanımında sınırlı data mevcuttur. Biz bu çalışmada parotis bezi lezyonlarında benign malign ayrımında B-mod ultrasonografi (US) ve USE bulgularının tanısal performansını değerlendirmeyi amaçladık. İkincil hedef olarak da en sık rastlanan benign parotis bezi lezyonlarını kendi içerisinde değerlendirmeyi hedefledik.

Yöntemler: Bu kesitsel çalışmada 48 hastada 57 lezyon değerlendirilmeye alındı. Her hasta iki radyolog tarafından muayene edildi. B-mod US (boyut, kontur, ciltten derinlik, içyapı, kalsifikasyon, kistik komponent) ve USE (gerinim oranı olarak belirtilen yarı nicel değer) bulguları not edildi. Her bulgu ayrı ayrı değerlendirildi. Her hastaya ince iğne aspirasyon biyopsisi ve sonrasında cerrahi rezeksiyon uygulandı.

Bulgular: Lezyonların 50’si benign, 7’si malign olarak patolojik tanı aldı. B-mod ultrason bulguları dikkate alındığında düzensiz kontur özelliğinin malign lezyonların ayrımında en yüksek doğruluk oranına (%85,7) sahip olduğu görüldü. USE bulguları değerlendirildiğinde gözlemciler içi uyum orta-ortanın altında; gözlemciler arası uyum ise orta olarak saptandı. Malign kitleler benign olanlar ile kıyaslandığında hafif daha yüksek gerinim oranı değerlerine sahip olmakla birlikte istatistiksel olarak anlamlı fark tespit edilmedi (P=0,422) ve güvenilir bir eşik değer saptanamadı.

Sonuç: USE ile meme ve tiroid lezyonlarındaki umut verici sonuçlar elde edilmesine rağmen parotis kitlelerinin değerlendirilmesinde konvansiyonel US bulguları ve ince iğne aspirasyon biyopsisi hala temel tanı aracı olarak geçerliliğini sürdürmektedir.

Keywords

• Ultrason elastografi,Strain elastografi,Gerinim oranı,Parotis bezi

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