不同材料金属烤瓷冠磁共振成像伪影的比较

Comparison of the artifacts on magnetic resonance imaging caused by different porcelain-fused-to-metals

背景:口腔内有金属烤瓷冠的患者在进行磁共振成像检查时会形成伪影,但是在临床方面鲜见有关不同材料金属烤瓷冠在磁共振成像形成伪影的定量报道。目的:研究不同材料金属烤瓷冠在FSE T2WI序列中磁共振成像伪影的大小。方法:在核磁室收集需做磁共振成像检查且有右下颌第一磨牙烤瓷冠修复的患者48例,分为镍铬合金烤瓷冠组、钴铬合金烤瓷冠组及纯钛烤瓷冠组。采用1.5T MRI扫描仪对所有患者进行FSE T2WI扫描,观察同一序列不同材料金属烤瓷冠患者成像伪影的大小。结果与结论:选择金属修复体边界出现清晰的弧形高信号环带且可进行测量的样本共45例,每种材料各15例。不同材料的金属烤瓷冠患者在同一序列产生的伪影大小不同,镍铬合金烤瓷冠组、钴铬合金烤瓷冠组和纯钛烤瓷冠组的伪影分别为(321.67±33.29),(263.53±34.95),(143.67±31.13)mm2,3组间两两比较差异均有显著性意义(P<0.05)。表明3种临床常用的金属烤瓷冠修复材料中,纯钛烤瓷冠形成的伪影最小,镍铬合金烤瓷冠伪影最大。

BACKGROUND：The patients with porcelain-fused-to-metal crowns who do examination of magnetic resonance imaging （MRI） can cause artifacts. In recent years, researching for MRI artifacts of different porcelain-fused-to-metal materials has been some progress, but there are less quantitatively reports on the MRI artifacts of different porcelain-fused-to-metal materials. OBJECTIVE：To evaluate the artifact sizes shown on fast spin-echo T 2-weighted sequence caused by different kinds of porcelain-fused-to-metal crowns. METHODS：Forty-eight lower right first molar crown patients who had MRI examination in MRI room were enrol ed. The patients were divided into nickel-chromium al oy group, cobalt-chromium al oy group and titanium crown group. Al patients were examined with fast spin-echo T 2-weighted sequences by means of 1.5 T MRI apparatus. MRI artifacts areas of same sequence on the MRI images of different porcelain-fused-to-metal materials were analyzed with variance test. RESULTS AND CONCLUSION：Forty-five cases appearing to have high signal samples with clearly curved boundary zone that can be measured were selected, 15 cases for each material. Different artifact sizes were produced on the same sequence of different porcelain-fused-to-metal materials, which were （321.67＆#177;33.29） mm in the nickel-chromium al oy group, （263.53＆#177;34.95） mm2 in the cobalt-chromium al oy group, and （143.67＆#177;31.13） mm2 in the titanium crown group. There were significant differences between groups （P＜0.05）. The artifact size is smal est for the titanium crown and largest for the nickel-chromium al oy crown.