Serial MR findings of Metaphyseal Cyst in Legg-Calve'-Perthes Disease: A Case Report

Metaphyseal cysts are common findings in Legg-Calv Perthes(LCP) disease, though usually disappear within 6-12 months. Several studies have described the MR imaging findings of these cysts, though serial MRI findings have not been documented. In this report, therefore, we report the serial MRI results of metaphyseal cyst in LCP patients.

MR Evaluation of "Metaphyseal" Change in Legg-Calve-Perthes Disease

PURPOSE: To determine the metaphyseal changes occurring in Legg-Calve-Perthes(LCP) disease using MRI. MATERIALS AND METHODS: Between 1992 to 1999, 80 LCP patients (87 hips) underwent MR imaging and plain radiography. All MR images were reviewed, bone marrow signal intensity, the size and location of the metaphyseal cyst and its epiphyseal necrosis grade determined. RESULTS: Metaphyses were abnormal in 43hips (49%), while bone marrow edema was present in 28 (32%) and a metaphyseal cyst in 30 (34%). Metaphyseal cysts were classified as either 'true' (n=9) or 'false' (n=21) according to the enhancement pattern. The maximum diameters of true and false cysts were 1.1+/-0.3 cm and 1.1+/-0.4 cm, respectively. Their most commom location was the anterior column; a true cyst occurred there in 7cases (78%), and false cyst in 16 (76%). Using the Waldenstrom classification, seven of the nine hips wih a true cyst (78%), were found to be at the avascular stage and 15 of the 21 with a false cyst (71%) were at the fragmentation stage. Seven of these nine (78%) and 19 of these 21 (90%) were Catterall grade IV. CONCLUSION: According to the findings of MR imaging, the metaphyseal changes occurring in LCP disease were bone marrow edema and metaphyseal cyst. This latter was visualized mainly in the anterior column and severely affected hip, and was classified as 'true' or 'false'.

Peripheral Cholangiocarcinoma: Radiologic Significance of Hypoechoic Halo Sign on Sonography

PURPOSE: To determine the prevalence and characteristics of the hypoechoic halo sign in peripheral cholangiocarcinoma. MATERIALS AND METHODS: Seventeen sonograms of 17 patients with peripheral cholangiocarcinoma histologically proven by either percutaneous needle biopsy (n=16) or surgical biopsy (n=1) were retrospectively reviewed. The size, margin, homogeneity and internal echogenicity of the masses as well as their peritumoral ductal dilatation and intratumoral calcification were ascertained, and the presence of a hypoechoic halo, and if present, its thickness and type, were also determined. We arbitrarily defined a 'thin' and 'thick' halo respectively, as one with a thickness less than of less than 3 mm, and 3 mm or more, and classified halos as 'intratumoral', 'extratumoral', or 'mixed'. RESULTS: Tumor diameter ranged from 4 to 13.5 (mean, 7.3) cm, and the margin was well-defined in 15 cases (smooth: n=2; lobulated: n=13) and irregular in two. Echogenicity was slightly heterogeneous in 11 cases, severely heterogeneous in three, and homogeneous in three, while the central portion was hyperechoic in eight cases, isoechoic in seven, and hypoechoic in only two. A hypoechoic halo was detected in 10 of 15 tumors(67%) with isoechoic centers. In evaluating the halo, two cases in which the mass was hypoechoic were excluded. All ten hypoechoic halos were at least 3 (range, 4-13; mean, 8.3) mm thick; in two cases the presence of a halo was equivocal, and in three there was no halo. Eight of ten halos were the mixed type, two were intratumoral, and none were extratumoral. Peritumoral ductal dilatation was seen in four cases (24%), but no internal calcification was observed. CONCLUSION: US showed that the margins of peripheral cholangiocarcinomas were mostly well-defined and smooth (12%) or lobulated (76%), and that masses were mainly heterogeneous (64%). A hypoechoic halo, which in all cases was thick and in 80% of cases was mixed, was noted in 67% of tumors with a hyper (47%) or isoechoic (41%) center. A halo of this kind may be useful in isoechoic mass detection and also in the differentiation of hyperechoic peripheral cholangiocarcinoma from hepatic hemangioma, the most common hyperechoic benign tumor.