Evaluation of thyroid lesions with gray scale ultrasound/ color doppler imaging and fine needle aspiration cytology correlation

ABSTRACT

Background: Thyroid gland is afflicted by various pathologies ranging from diffuse enlargement (goitre) to nodular lesions, thyroiditis, and malignancy. Presently high resolution ultrasound with color Doppler is the primary imaging modality of choice in morphological evaluation of thyroid gland. It is used to define the nature of the lesion, whether solid or cystic, to differentiate thyroid from extra thyroidal masses, to assess the size of nodule in patients who are under observation or therapy, to monitor patient who are at increased risk of thyroid malignancy especially those with radiation exposure or having a family history, to detect recurrence of thyroid malignancy after surgery and in interventional procedure like guiding in FNAC. Materials and methods: Study was carried out using standard 5-12 MHz frequency probe with grey scale and color Doppler spectrum to evaluate and analysis of different thyroid nodules and taking Ultrasound guided fine needle aspiration cytology and correlate histopathologically. Results: Majority of patients belonged to middle age group between 21-60 years with mean age of 38.2 years. Colloid goitre was most common presentation on ultrasound and it showed wide spectrum of appearance, majority being nodular with anechoic echotexture. Malignant lesions of thyroid were usually hypoechoic, though all hypoechoic lesions were not malignant. (Sensitivity of 75%, specificity of 81.48%, PPV of 37.5% and NPV 95.65%). The most sensitive sign for picking up malignancy on USG were Intralesional vascularity; absent halo sign and regional lymph node Siddharth Zala, C. Raychaudhuri. Evaluation of thyroid lesions with gray scale ultrasound/ color doppler imaging and fine needle aspiration cytology correlation. IAIM, 2019; 6(4) 86-91. Page 87 involvement (sensitivity of 100%) the most specific signs were invasion of adjacent tissue (specificity of 92.59%), Lymphadenopathy (85.18%) and hypoechotexture (81.48%). A combination of signs aid in prediction of malignancy and in guidance for site of FNAC. The most useful combination of sign proved to be Invasion to adjacent tissue, Lymphadenopathy, absent halo, hypoechogenicity, microcalcification and Intralesional vascularity on color flow imaging. Conclusion: The ultrasonographic findings in thyroiditis were usually hetroechogenicity and coarse calcification with diffuse vascularity on color flow imaging. The addition of color flow imaging to gray scale ultrasound had increased the overall sensitivity for diagnosis of thyroiditis (96.87%) and was also highly specific (89.70%)