Value and Clinical Application of Orthopedic Metal Artifact Reduction Algorithm in CT Scans after Orthopedic Metal Implantation

Abstract

ObjectiveTo evaluate orthopedic metal artifact reduction algorithm (O-MAR) in CT orthopedic metal artifact reduction at different tube voltages, identify an appropriate low tube voltage for clinical practice, and investigate its clinical application.Materials and MethodsThe institutional ethical committee approved all the animal procedures. A stainless-steel plate and four screws were implanted into the femurs of three Japanese white rabbits. Preoperative CT was performed at 120 kVp without O-MAR reconstruction, and postoperative CT was performed at 80–140 kVp with O-MAR. Muscular CT attenuation, artifact index (AI) and signal-to-noise ratio (SNR) were compared between preoperative and postoperative images (unpaired t test), between paired O-MAR and non-O-MAR images (paired Student t test) and among different kVp settings (repeated measures ANOVA). Artifacts' severity, muscular homogeneity, visibility of inter-muscular space and definition of bony structures were subjectively evaluated and compared (Wilcoxon rank-sum test). In the clinical study, 20 patients undertook CT scan at low kVp with O-MAR with informed consent. The diagnostic satisfaction of clinical images was subjectively assessed.ResultsAnimal experiments showed that the use of O-MAR resulted in accurate CT attenuation, lower AI, better SNR, and higher subjective scores (p < 0.010) at all tube voltages. O-MAR images at 100 kVp had almost the same AI and SNR as non-O-MAR images at 140 kVp. All O-MAR images were scored ≥ 3. In addition, 95% of clinical CT images performed at 100 kVp were considered satisfactory.ConclusionO-MAR can effectively reduce orthopedic metal artifacts at different tube voltages, and facilitates low-tube-voltage CT for patients with orthopedic metal implants.

Orthopaedic metallic artefact reduction algorithm facilitates CT evaluation of the urinary tract after hip prosthesis

“…21 In a prior study by Hu et al, O-MAR showed high efficacy even at low-voltage acquisitions with 80 keV. 22 The authors concluded that O-MAR showed a remarkable reduction in metallic artefacts not only at high, but also low, tube voltages. Therefore, they recommended its use for low-voltage Figure 4 Cases where O-MAR facilitated the diagnosis.…”

“…First, the number of patients is relatively small compared to other studies conducted with O-MAR. The average cohort size in the three clinical studies 7,22,25 published on O-MAR reconstruction after hip arthroplasty was 48 patients. Therefore, the present findings have to be validated using a larger cohort.…”

Evaluation of Orthopedic Metal Artifact Reduction Application in Three-Dimensional Computed Tomography Reconstruction of Spinal Instrumentation: A Single Saudi Center Experience

“…A blinded consultant radiologist, with more than 15 years of experience in radiological diagnosis, conducted the subjective evaluations including severity of the spinal metallic artifacts, density of the related paraspinal muscles, clarity of the intermuscular fat planes, and definition of the scanned vertebral elements using a 5-point scale [ Table 1 ]. [ 1 ] Images scoring 3 or more were considered radiologically satisfactory.…”

“…Magnetic resonance imaging evaluation is limited due to the magnetic severe susceptibility artifacts; so, computed tomography (CT) is now the method of choice for the postoperative assessment of spinal metallic instrumentation. [ 1 2 ] However, the presence of spinal metal implants produces considerable artifacts on CT images, resulting in marked degradation of image quality and subsequent changes of CT attenuation values of the surrounding tissues, which seriously influences the reliability of the postoperative three-dimensional CT (3DCT) assessment of spinal instrumentation. [ 3 ] Hence, many studies investigated the metallic artifact reducing methods used in clinical practice including linear interpolation,[ 4 ] spline interpolation,[ 5 ] simultaneous algebraic reconstruction,[ 6 ] and simultaneous iterative reconstruction[ 7 ] techniques.…”

Radiological Evaluation of Spinal Instrumentation as Treatment for Adolescent Idiopathic Scoliosis, a Single Saudi Center 5-Year Experience

“…Although long-term radiological outcomes have been reported for earlier spinal constructs, the radiological evaluation of spinal instrumentation with pedicle screws were mainly based on short follow-up studies with scarce longer term results [20] [21] [22] [23] [24]. Kim et al [25] compared hybrid and screw constructs with 5-year minimum follow-up in proximal junctional kyphosis mainly.…”