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.

CT Features of Second Branchial Cleft Cysts: Emphasis on the Locations of Lesionst

PURPOSE: The purpose of this study was to evaluate the CT features of second branchial cleft cysts. MATERIALS AND METHODS: We retrospectively analyzed the computed tomographic images in nine cases of second branchial cleft cyst which was confirmed pathologically. Emphasis was on localization of the masses to fascial spaces as defined by the deep cervical fasica. RESULTS: In all nine cases, the lerions were located in the submandibular and carotid spaces. Among these cases, six(67%) had simultaneous involvement of the other contiguous spaces, such as anterior and posterior cervical spaces. All cases had round or oval, unilocular, cystic masses with partial or complete rim enhancement. In eight cases(89%), smooth and thin walls were observed. In one case, thick wall and septations were noted. No definite calcifications were noted in all cases. The internal contents of cystic masses showed relatively homogeneous appearance, and CT number ranged from 20 to 35.2 Hounsfield unit(HU)(mean, 28.4HU). CONCLUSION: CT diagnosis of second branchial cleft cyst would be easily obtained from recognition of frequent simultaneous involvement of the other contiguous spaces, along with a typical location and characteristic morphology.

Hypertrophic pyloric stenosis:pre- and post-operative sonographic findings

The authors retrospectively analysed the ultrasonographic findings of 43 cases of surgically confirmed hypertrophic pyloric stenosis and their postoperative findings of sonograms taken at 1 month(n=40) or 3 months( n=5) after pyloromyotomy. In preoperative study, the thickened pyloric muscle was isoechoic or slight hypoechoic relative to liver on the midline longitudinal view and appeared as a "nonuniform acoustic ring" on the transverse view. The results of measurement in the all cases with hypertrophic pyloric stenosis were the pyloric thickness ≥3.8mm, the pyloric diameter ≥14mm, the pyloric channel length ≥16mm, the pyloric muscle volume ≥2.21Cm