Diagnostic accuracy of gray-scale and colour doppler ultrasonography in diagnosing malignant thyroid nodules

Objective: To determine diagnostic accuracy of gray-scale and colour doppler ultrasonography in diagnosing malignant thyroid nodules. Study Design: Validation study. Place and Duration of Study: Radiology department Combined Military Hospital (CMH) and Military Hospital (MH) Rawalpindi from July 2007 to July 2008. Subjects and Methods: Fifty cases of solitary/multinodular goitre with clinical suspicion of malignancy were included in the study by non-probability purposive sampling. Gray-scale and colour doppler ultrasonography of neck/thyroid gland was done and results were compared with histo-pathological findings from Armed Forces Institute of Pathology (AFIP) and Army Medical College keeping histopathology as gold standard. Results: In 50 patients, 10 cases found to have ultrasound findings suspicious of malignancy. Out of these 10 cases, 6 cases confirmed as malignant on histopathology. In 40 patients with benign ultrasound findings, one had malignancy on histo-pathological examination. Out of these 7 patients with confirmed malignancy, four had papillary carcinoma; two had follicular carcinomas and one anaplastic carcinoma. Diagnostic parameters calculated and found to be: sensitivity 85.7 percent; specificity 90.6 percent; PPV 60 percent; NPP 97.5 percent and accuracy of 90 percent. Conclusion: Gray-scale and colour doppler ultrasonography is a good technique in diagnosing malignant thyroid nodules. Entirely solid nodule with no cystic element having spiculated margins, micro-calcifications and central flow are helpful sonographic findings pointing towards malignancy. Associated cervical lymphadenopathy with calcification or degeneration is a significant finding favouring malignancy. (author)