[en] Objective: To study the diagnostic value of calcification in differentiating benign and malignant thyroid lesions. Methods: CT images of 318 consecutive patients with pathologically proven thyroid lesions were retrospectively reviewed by two radiologists. The following characteristics of calcification on CT images were evaluated: (1) size (≤ 2 mm indicating microcalcification and >2 mm or shelly and irregular shape indicating macrocalcification, and both features indicating mixed calcification), (2) number (single or multiple) and (3) location (internal or edge). X² test was used for statistical analysis. Results Of the 318 cases, 48 were diagnosed as malignant (papillary carcinoma 26, follicular carcinoma 7, medullary carcinoma 3 and microcarcinoma 12) and 270 were benign (nodular goiter 36, adenoma 170, nodular goiter with adenoma 38 and adenoma with Hashimoto's thyroiditis 26). Calcification was found in 60 cases (18.9%). Among them 21 (papillary carcinoma 12, microcarcinoma 6, follicular carcinoma 2 and medullary carcinoma 1) were malignant (43.8%) and 39 (nodular goiter 6, adenoma 13, nodular goiter with adenoma 19 and adenoma with Hashimoto's thyroiditis 1) were benign (14.4%) (P<0.01). Sensitivity and specificity for diagnosing thyroid carcinoma were 43.8% (21/48) and 85.6% (231/270), respectively. Microcalification was found in 37 cases (malignant 8, benign 29) and macrocalcification was found in 23 cases (malignant 13, benign 10) (P<0.01). Sensitivity and specificity of macrocalcification for diagnosing thyroid carcinoma were 61.9% (13/21) and 74.4% (29/39), respectively. Single calcification was found in 31 cases (malignant 13, benign 18) and multiple calcification was found in 29 cases (malignant 8, benign 21) (P>0.05). Internal calcification was found in 15 cases of malignant lesions (71.4%) and 12 of benign lesions (30.8%); Edge calcification was found in 6 cases of malignant and 27 of benign, (P<0.01). Sensitivity and specificity of internal calcification for diagnosing thyroid carcinoma were 71.4% (15/21) and 69.2% (27/39), respectively. Conclusion: Internal calcification or (and) macrocalcification of t he thyroid lesions may strongly suspect thyroid carcinoma and fine-needle aspiration or surgery should be further performed. (authors)

[en] Objective: To evaluate MRI in the diagnosis of the bone contusion of the knee .joint and its clinical significance. Methods: Using special coil for knee joint, coronal, sagittal, axial and oblique sagittal plane scanning with fast spin-echo sequence(T₁WI, T₂WI, PDWI + FS) was performed on knee joint in 205 patients in three days after injury. According the distributing bone marrow edema and injury mechanism, bone contusion were classified five types as pivot shift injury, clip injury, dashboard injury, hyperextension injury and lateral patellar dislocation. Results: One hundred and forty-five cases of the 205 patients were found bone marrow edema without fracture on X-ray films. Among them, pivot shift injury was found in 43 cases accompanied with anterior cruciate ligament rupture in 30 cases, tear of the posterior horn of the lateral or medial meniscus in 12 and tears of the medial collateral ligament in 8 cases; clip injury in 53 cases accompanied with anterior cruciate ligament rupture in 10 cases, tear of the posterior horn of the lateral or medial meniscus in 15 and tears of the medial collateral ligament in 38 cases; dashboard injury 40 cases accompanied with posterior cruciate ligament rupture in 16 cases, hyperextension injury. 9 cases accompanied with anterior cruciate ligament rupture in 2 cases, posterior cruciate ligament rupture in 3 cases. No lateral patellar dislocation was found. Forty-eight of 145 patients had undergone arthroscopy, 43 cases (89.6%) of them were in accordance with Mill diagnosis. Bone contusion were defined as geographic regions of abnormal signal intensity, that is, low signal intensity in T₁-weighted images and high signal intensity in PD-weighted or T₂-weigeted images with fat saturation. Conclusion: MRI can accurately display the location and area of bone contusion of the knee joint as well as its adjunctive structure injury and deduce their injury mechanism. MRI should be used routinely for knee trauma. (authors)

[en] Objective: To analyze the MRI feature of cesarean scar pregnancy (CSP) for treatment planning. Methods: MRI of 16 patients with suspected CSP from 2010 to 2013 was retrospectively analyzed and compared with surgical findings. Results: All gestational sacs were clearly demonstrated on MRI with 14 embedded in the anterior cervix and diagnosed as CSP. The gestational sacs were cystic (8/14) or heterogeneous (6/14), located within the uterine cavity (4/14) or deeply implanted in the scar (10/14). Suction and curettage were performed in 6/14 and uterine artery embolization in 8/14. Two patients were diagnosed as early abortion and treated by suction and curettage. Conclusion: MRI is useful in the management of CSP. (authors)