Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Vet Radiol Ultrasound. 2023 Jul;64(4):677-685. doi: 10.1111/vru.13258. Epub 2023 Jun 6.
Metal artifacts in CT negatively impact the evaluation of surgical implants and the surrounding tissues. The aim of this prospective experimental study was to evaluate the ability of a single energy metal artifact reduction (SEMAR™, Canon) algorithm and virtual monoenergetic (VM) dual-energy CT (DECT) scanning techniques to reduce metal artifacts from stainless steel screws surgically inserted into the equine proximal phalanx. Seven acquisitions of 18 cadaver limbs were performed on a Canon Aquilion One Vision CT scanner (Helical +SEMAR, Volume +SEMAR, Standard Helical, Standard Volume and VM DECT at 135, 120, and 105 keV) and reconstructed in a bone kernel. Blinded subjective evaluation performed by three observers indicated a significant effect of acquisition in both adjacent tissues (P < 0.001) and distant tissues (P < 0.001) and the best metal artifact reduction was seen with Helical +SEMAR and Volume +SEMAR. The subjective overall preference of CT acquisition type was (1) Helical +SEMAR, (2) Volume +SEMAR, (3) VM DECT 135 keV, (4) VM DECT 120 keV, (5) VM DECT 105 keV, (6) Standard Helical, (7) Standard Volume (P < 0.001). Unblinded objective evaluation performed by one observer showed that VM DECT 120 keV, Helical +SEMAR, and Volume +SEMAR performed similarly and were objectively the best at reducing blooming artifact. Overall, the best metal artifact reduction was obtained with SEMAR, followed by VM DECT. However, VM DECT performance varies with energy level and was associated with decreased image quality in distant tissues and artifactual overcorrection of metal artifacts at high energy levels.
CT 中的金属伪影会对手术植入物及其周围组织的评估产生负面影响。本前瞻性实验研究的目的是评估单能金属伪影降低（SEMAR™，佳能）算法和虚拟单能（VM）双能 CT（DECT）扫描技术降低不锈钢螺钉植入马近节段骨后金属伪影的能力。在佳能 Aquilion One Vision CT 扫描仪（螺旋+SEMAR、容积+SEMAR、标准螺旋、标准容积和 VM DECT 135keV、120keV 和 105keV）上对 18 个尸体肢体的 7 次采集进行了扫描，并在骨核中进行了重建。三位观察者进行的盲法主观评估表明，在相邻组织（P<0.001）和远处组织（P<0.001）中采集都有显著影响，并且螺旋+SEMAR 和容积+SEMAR 具有最佳的金属伪影降低效果。CT 采集类型的总体主观偏好为（1）螺旋+SEMAR，（2）容积+SEMAR，（3）VM DECT 135keV，（4）VM DECT 120keV，（5）VM DECT 105keV，（6）标准螺旋，（7）标准容积（P<0.001）。一位观察者进行的非盲法客观评估显示，VM DECT 120keV、螺旋+SEMAR 和容积+SEMAR 表现相似，在降低blooming 伪影方面效果最佳。总体而言，SEMAR 可获得最佳的金属伪影降低效果，其次是 VM DECT。然而，VM DECT 的性能随能量水平而变化，并且与远处组织的图像质量下降和高能水平下金属伪影的过度校正有关。
