CT radiation dose reduction in patients with total hip arthroplasties using model-based iterative reconstruction and orthopaedic metal artefact reduction

Abstract

ObjectiveTo evaluate the impact of radiation dose reduction on image quality in patients with metal-on-metal total hip arthroplasties (THAs) using model-based iterative reconstruction (MBIR) combined with orthopaedic metal artefact reduction (O-MAR).Materials and methodsPatients with metal-on-metal THAs received a pelvic CT with a full (FD) and a reduced radiation dose (RD) with −20%, −40%, −57%, or −80% CT radiation dose respectively, when assigned to group 1, 2, 3, or 4 respectively. FD acquisitions were reconstructed with iterative reconstruction, iDose4. RD acquisitions were additionally reconstructed with iterative model-based reconstruction (IMR) levels 1–3 with different levels of noise suppression. CT numbers, noise and contrast-to-noise ratios were measured in muscle, fat and bladder. Subjective image quality was evaluated on seven aspects including artefacts, osseous structures, prosthetic components and soft tissues.ResultsSeventy-six patients were randomly assigned to one of the four groups. While reducing radiation dose by 20%, 40%, 57%, or 80% in combination with IMR, CT numbers remained constant. Compared with iDose4, the noise decreased (p < 0.001) and contrast-to-noise ratios increased (p < 0.001) with IMR. O-MAR improved CT number accuracy in the bladder and reduced noise in the bladder, muscle and fat (p < 0.01). Subjective image quality was rated lower on RD IMR images than FD iDose4 images on all seven aspects (p < 0.05) and was not related to the applied radiation dose reduction.ConclusionIn RD IMR with O-MAR images, CT numbers remained constant, noise decreased and contrast-to-noise ratios between muscle and fat increased compared with FD iDose4 with O-MAR images in patients with metal-on-metal THAs. Subjective image quality reduced, regardless of the degree of radiation dose reduction.

Diagnostic Performance of Dual-Energy CT for Detecting Painful Hip Prosthesis Loosening

“…Although several approaches were suggested to reduce the artifacts caused by prostheses, including the optimization of single-energy CT scanning (14), iterative reconstructions, and specific software for iterative metal artifact reduction (18,19), these techniques can generate new artifacts, such as blurring and shape distortion (20-26). Moreover, in the study by Bamberg et al ( 23), image quality with DECT was superior to that with single-energy CT in 29 of 31 cases.…”

Application of low‐dose CT to the creation of 3D‐printed kidney and perinephric tissue models for laparoscopic nephrectomy

“…At present, the methods for reducing the CT radiation dose include reducing the tube voltage, reducing the tube current, shortening the scanning time, and applying iterative algorithms. 14,15 Liu et al 12 proved that low-dose CT scanning technology (100 kVp) in renal CTA examination can significantly decrease ED, by 37.24%. However, we chose 80 kVp in the present study, further reduced the tube voltage, and decreased ED by approximately 50.54%.…”

Low-dose CT with metal artifact reduction in arthroplasty imaging: a cadaveric and clinical study

“…Adopting this type of postoperative protocol that includes multiple follow-up CT scans further highlights the importance of minimizing radiation exposure in this patient population [15]. Recently introduced advanced MAR techniques have not only shown substantial benefit in reducing artifact compared with standard CT techniques when imaging patients with arthroplasties, including TSAs [23,24] and reverse shoulder arthroplasties [25], but have also shown the potential to reduce the high radiation exposure associated with standard MAR CT techniques (generally in phantom studies) [5][6][7]. The purpose of this study, therefore, was to determine whether a lower-dose protocol using an advanced MAR CT technique could be used in a clinical setting to evaluate bone and soft tissue structures adjacent to hardware without compromising the ability to detect pathology.…”

“…To our knowledge, only one human study has assessed reduced-dose and full-dose CT in patients with metal-onmetal hip arthroplasties using an advanced MAR technique from a single vendor [7]. This study found that subjective image quality with reduced-dose CT was significantly worse than with full-dose CT. We have found no other reports of clinical studies evaluating low-dose MAR CT for other types of implants or using other MAR techniques.…”

“…In recent CT phantom studies, these advanced MAR techniques have been shown to not only reduce metal artifacts to a greater degree than traditional techniques but to do so while reducing the high radiation exposure associated with traditional methods [5,6]. Specifically, Wellenberg et al [5,7] found that using an advanced MAR reconstruction technique (O-MAR, Phillips) in combination with iterative reconstruction allowed a dose reduction of 83% (while still maintaining a diagnostic contrast-tonoise ratio) when compared with traditional techniques using filtered back projection. Similarly, Subhas et al [6] found that the accuracy of lesion detection adjacent to metal implants when using a half-dose sinogram inpainting technique (iMAR, Siemens) was significantly higher than the accuracy seen with a high-dose traditional CT MAR technique in a phantom study.…”