Choi Jung-Yoo Chesaria, Choi Cham Albert, Yeo In-Sung Luke
Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
Department of Field Refurbishment, Optoscan, Seoul, Korea.
J Periodontal Implant Sci. 2018 Aug 29;48(4):202-212. doi: 10.5051/jpis.2018.48.4.202. eCollection 2018 Aug.
Bone-to-implant contact (BIC) is difficult to measure on micro-computed tomography (CT) because of artifacts that hinder accurate differentiation of the bone and implant. This study presents an advanced algorithm for measuring BIC in micro-CT acquisitions using a spiral scanning technique, with improved differentiation of bone and implant materials.
Five sandblasted, large-grit, acid-etched implants were used. Three implants were subjected to surface analysis, and 2 were inserted into a New Zealand white rabbit, with each tibia receiving 1 implant. The rabbit was sacrificed after 28 days. The specimens were subjected to spiral (SkyScan 1275, Bruker) and round (SkyScan 1172, SkyScan 1275) micro-CT scanning to evaluate differences in the images resulting from the different scanning techniques. The partial volume effect (PVE) was optimized as much as possible. BIC was measured with both round and spiral scanning on the SkyScan 1275, and the results were compared.
Compared with the round micro-CT scanning, the spiral scanning showed much clearer images. In addition, the PVE was optimized, which allowed accurate BIC measurements to be made. Round scanning on the SkyScan 1275 resulted in higher BIC measurements than spiral scanning on the same machine; however, the higher measurements on round scanning were confirmed to be false, and were found to be the result of artifacts in the void, rather than bone.
The results of this study indicate that spiral scanning can reduce metal artifacts, thereby allowing clear differentiation of bone and implant. Moreover, the PVE, which is a factor that inevitably hinders accurate BIC measurements, was optimized through an advanced algorithm.
由于伪影会妨碍对骨组织和植入物的准确区分，因此在微型计算机断层扫描（CT）上很难测量骨与植入物的接触（BIC）。本研究提出了一种先进的算法，用于在微型CT采集中使用螺旋扫描技术测量BIC，该算法能更好地区分骨组织和植入物材料。
使用了五枚经过喷砂、大颗粒、酸蚀处理的植入物。对其中三枚植入物进行表面分析，另外两枚植入新西兰白兔体内，每只胫骨植入一枚。28天后处死兔子。对标本进行螺旋（SkyScan 1275，布鲁克公司）和圆形（SkyScan 1172、SkyScan 1275）微型CT扫描，以评估不同扫描技术所产生图像的差异。尽可能优化部分容积效应（PVE）。在SkyScan 1275上分别使用圆形扫描和螺旋扫描测量BIC，并比较结果。
与圆形微型CT扫描相比，螺旋扫描显示的图像更清晰。此外，PVE得到了优化，从而能够进行准确的BIC测量。在SkyScan 1275上进行圆形扫描得到的BIC测量值高于同一机器上的螺旋扫描；然而，圆形扫描中较高的测量值被证实是错误的，是由孔隙中的伪影导致的，而非骨组织。
本研究结果表明，螺旋扫描可减少金属伪影，从而清晰区分骨组织和植入物。此外，通过一种先进算法优化了部分容积效应，该效应是不可避免地妨碍准确测量BIC的一个因素。
