不同年龄组健康小儿磁共振全身扩散加权成像的表现

目的：探讨不同年龄组健康小儿全身扩散加权成像（WB-DWI）表现，为此技术应用于临床疾病的诊断奠定基础。方法：70例健康体检儿，年龄1个月～15岁，按照年龄分成3组：1～12个月、1岁以上～5岁、5岁以上～15岁，在家长知情同意下接受WB-MRI检查，比较不同年龄组之间全身扩散加权图像上信号的差异，并进行相关性分析。结果：wBDwI上双肺、纵隔、肝脏、胰腺及周围软组织呈低信号，脑、脾、肾、睾丸及充盈的膀胱呈高信号，各脏器之间信号无明显差异。四肢长管状骨干骺端及骨干信号强度均随年龄增长而逐渐减低。1个月左右的小儿在WB-DwI上显示四肢骨结构模糊；在2～12个月组长管状骨干骺端表现为高信号者占66．7％，在12个月以上～5岁组占43．4％，5～15岁组为7．7％；长管状者骨干表现为高信号者在2～12个月组占28．6％，1岁以上～5岁组占17．3％，5岁以上～15岁组高信号基本消失。颈部、腋窝、颌下、髂血管周围淋巴结及中下腹、盆腔内部分肠管在WB-MRI上也显示为高信号。结论：WB-DWI技术作为一种无创性检查可在较短时间内完成小儿全身检查，图像能够满足临床诊断要求。正确认识小儿WB-DWI正常表现，为临床诊断疾病奠定基础。

Whole body diffusion-weighted MR imaging in children of different age groups

Objective：To investigate the findings of whole body diffusion-weighted imaging （WB-DWI） in children of different age groups, in order to obtain the basic reference for the diagnosis of clinical diseases. Methods： 70 healthy children （0～15y of age） were divided into 3 groups according to age：less than 12 m, 12m to 5y and more than 5y. Consent was signed by parents and agreed to accept body magnetic resonance diffusion weighted imaging （WB-DWI）. Difference of signal intensities on WB-DWI of different age groups were compared and correlation analysis was performed. Results： Bilateral lungs,mediastinum,liver, pancreas and soft tissue showed low signal intensity whereas brain, spleen, kidney, scrotum and fulfilled urinary bladder showed high signal intensity. No obvious difference could be revealed in different organs. The signal intensity of metaphysis and diaphysis in long bones of extremities reduced gradually following increase of age. On WB-DWI, inconspicuous bone structure of extremities was found in infants lm of age. High signal intensity of metaphysis could be seen in 66.7% of infants around lm of age;in 43.4%of 1～5y;7.7% in 5～15y of age. High signal intensity in diaphysis of long bone was assessed in 28.6%of infants 2～12m,17.3% in 1～5y and basically vanished in 5～15y of age. Lymph nodes in the neck, axilla, submandibular region,iliac region as well bowel in mid-lower abdomen, pelvis presented as high signal in- tensities on WB-DWI. Conclusion：WB-DWI can be used as a non-invasive whole body examination in children,the examina- tion could be completed in a relatively short period of time. The images can fulfill the requirement of clinical diagnosis. Un- derstanding of the normal manifestations of WB-DWI in children could lay the foundation for its clinical diagnostic applica- tion.