Department of Experimental and Clinical Biomedical Sciences Radiodiagnostic Unit n. 2, University of Florence-Azienda Ospedaliero-Universitaria Careggi, Largo Brambilla 3, 50134, Florence, Italy,
Radiol Med. 2015 Jul;120(7):618-26. doi: 10.1007/s11547-015-0496-2. Epub 2015 Jan 30.
This study aimed at evaluating incidence/degree of metal/motion artifacts and CT-dose-index in oral/maxillofacial examinations using Cone-Beam-CT.
Interferences caused by metal and motion artifacts were evaluated in 500 patients aged from 6 to 81 years, in dental arches, maxillofacial and splanchocranium Cone-Beam-CT exams. The interferences was divided into four progressive degrees (G0-G3) related to the possibility to answer the clinical query. The parameters considered were field-of-view, scan time, patient's age, and anatomical area. Furthermore volumetric CT-dose-index was measured.
In the presence of metal artifacts the clinical query was always answered (G3 = 0). No artifacts (G0) were found in all cases when metal was beyond 5 cm from interest site and in 18.4% when metal was inside this distance. Beam hardening and photon starvation due to implants, restoration and orthodontic therapies achieved 56.2% G1 and 25.4% G2. Motion artifacts were more frequent in under ten (31.5%) and over sixty (82.2%), and in mandible analysis (inferior arch 59.5%, both arches 47.3%). Moreover, their incidence and intensity were influenced by scan time (49.1% at 36 s) but not by field-of-view. Mean volumetric CT-dose-index of all patients was mGy 9.11 (mGy 3.62, 5.78, 8.89, and 13.07 at 18, 24, 26, and 36 s, respectively).
In our series Cone-Beam-CT diagnostic evaluation was never inhibited by metal artifacts and only in 1.9% of the cases by motion artifacts, always with a very low CT-dose-index.
本研究旨在评估口腔/颌面锥形束 CT 检查中金属/运动伪影的发生率/程度和 CT 剂量指数。
对 500 名年龄在 6 至 81 岁的患者的牙弓、颌面和颅面锥形束 CT 检查中的金属和运动伪影干扰进行评估。干扰分为四个渐进程度（G0-G3），与回答临床疑问的可能性相关。考虑的参数包括视野、扫描时间、患者年龄和解剖区域。此外，还测量了容积 CT 剂量指数。
在存在金属伪影的情况下，临床询问总是可以得到回答（G3=0）。当金属距离感兴趣区域超过 5 厘米时，所有情况下均未发现伪影（G0），当金属在该距离内时，18.4%的情况下未发现伪影。由于植入物、修复体和正畸治疗导致的束硬化和光子饥饿导致 56.2%的 G1 和 25.4%的 G2。运动伪影在十岁以下（31.5%）和六十岁以上（82.2%）以及下颌骨分析中更为常见（下弓 59.5%，双弓 47.3%）。此外，它们的发生率和强度受扫描时间的影响（36 秒时为 49.1%），但不受视野的影响。所有患者的平均容积 CT 剂量指数为 mGy 9.11（18、24、26 和 36 s 时分别为 mGy 3.62、5.78、8.89 和 13.07）。
在我们的系列研究中，锥形束 CT 诊断评估从未因金属伪影而受到抑制，只有 1.9%的病例因运动伪影而受到抑制，且 CT 剂量指数始终非常低。
