Radiological diagnosis of thyroid nodules

The efficacy of plain radiography, radionucleide study (RN), ultrasonography (US), computed tomography (CT) and angiography in differentiating malignant from benign thyroid nodules in 102 patients was studied. Special attention was paid angiography because of several reports stressing its usefulness. The plain radiographs, RN, and US were all available for review, but the CT of 36 patients and the angiograms of 88 patients were not. Angiographic findings such as arterial encasement, tumor vessels and tumor stains (homogeneous or heterogeneous) were not reliable as criteria to make the differentiation. Only the combination of tumor stains, tumor margins and halo were helpful. Ninety-six percent of vascular tumors without halo were malignant. Seventy-one percent of vascular tumors with halo were benign and 29% were malignant. Among fifty-seven percent of avascular tumors were benign, 43% were malignant, indicating the difficulty in differentiating malignant from benign lesions using this means. On combining plain radiography, RN, US to diagnose thyroid nodules, the differentiation was still difficult. Further examinations such as angiography in addition to these examinations was not helpful. This study indicated that thyroid angiography should be avoided because it often misleads in diagnosis, and because of possible neurological complications using carotid catheterization. (author)