Thallium 201 Thyroid Scan: Differential Diagnosis of Benign and Malignant Nodules

PURPOSE: To evaluate useful findings and diagnostic value of TI-201 thyroid scan in differentiating benign from malignant nodules. MATERIAL AND METHOD: We studied 77 cold thyroid nodules proven histologically(27 malignat and 50 benign). Early (5--15rain) and delayed images(3--5hours) were obtained after intravenous injection of thallium 201. In these nodules, we retrospectively analyzed the degree of TI-201 uptake in early and delayed images, histopathologic type, size, and presence or absence of cystic change in the sonograms of 22 malignant nodules. RESULTS: Useful finding for diagnosis of malignant nodules was strong uptake of TI-201 in early and delayed images(specificity:98%, sensitivity:63%, positive predictive value:94.4%). Useful finding for benign nodules was no uptake of TI-201 in delayed image(specificity :88.9%, sensitivity :68%, positive predictive value :91.9%). The accuracy of TI-201 thyroid scan in differentiating benign from malignant nodules was 66.2%. The nodules with strong TI-201 uptake in early image and low TI-201 uptake in delayed image were malignant in 29.4%. Cystic changes were found in 40% of malignant nodules with atypical TI-201 uptake. TI-201 thyroid scan showed high specificity in follicutar neoplasm and adenomatous goiter in which differentiation of benignancy and malignancy is difficult with only cytologic examination. CONCLUSION: We consider that TI-201 thyroid scan is valuable in differentiating benign from malignant nodules and when combined with fine needle aspiration and ultrasound examination, it will enable more accurate differential diagnosis between benign and malignant thyroid nodules.

Intussusception in Childhood: The Role of Plain Abdominal Radiographs

PURPOSE: The purposes of this study were to evaluate the plain radiologic findings of the childhood intussusception and to evaluate the role of plain abdominal films in predicting the success of air or barium reduction. SUBJECTS AND METHODS: We retrospectively reviewed 140 cases with the diagnosis of intussusception in children. The radiological signs that included soft tissue mass, dilatation of small bowel suggesting obstruction, crescent sign, and target sign were evaluated in terms of frequency. The relationship between radiological findings and outcome of reduction was analyzed. The site of soft tissue mass or crescent sign seen on plain radiographs was correlated with the position of the apex of the intussusceptum seen at the beginning of barium enema. The degree of dilated small bowel was evaluated by calculating the proportion of air-filled small bowel occupying peritoneal cavity and measuring the maximal diameter of dilated bowel lumen. The radiological finding for small bowel obstruction is determined by observation of the degree of small bowel dilatation and/or air-fulid levels. RESULTS: Ninety-two cases out of 140 showed one or more radiographic signs. Two most common signs were soft tissue mass and small bowel obstruction. The success rate of air or barium reduction was significantly lower in patients with most severe degree of dilatation of small bowel and/or more than 7 air-fulid levels on erect view. The suspected location of intussusception on plain radiographs correlated well with the true location of intussusception seen in the first few seconds of barium reduction. CONCLUSION: Plain abdominal radiography is useful in the diagnosis of intussusception and provides helpful informations for the reduction procedure as well as for the exclusion of the contraindications such as bowel perforation.