Multichannel CT Imaging of Orthopedic Hardware and Implants

ABSTRACT

The introduction of multichannel CT scanners provides both radiologists and surgeons with a new tool to image patients with orthopedic hardware. The key parameters that have made it possible to image the implants and the surrounding bone with multichannel CT are the higher available technical factors (kVp and mAs) coupled with the ability to acquire thin slices over a large scan region. These properties make it possible to produce high-quality multiplanar reformations that facilitate visualization of the orthopedic device and the surrounding bone. An important consideration for multichannel CT imaging of hardware is the reduction of cone beam artifacts caused by the geometry of multichannel CT scanners. This artifact is reduced by using a narrower x-ray beam collimation and a low pitch setting. This article discusses CT scan parameters and image postprocessing used at our institution and illustrates common clinical problems encountered when imaging implanted orthopedic devices. These include fracture healing, loosening of joint prostheses, evaluation of particle disease, and the use of CT for preoperative planning in revision arthroplasty.

KEYWORDS

X-ray computed tomography - CT - bone - joint prosthesis - prostheses and implants

REFERENCES

• 1 White L M, Buckwalter K A. Technical considerations: CT and MR imaging in the postoperative orthopedic patient.  Semin Musculoskelet Radiol. 2002;  6 5-17
• 2 Fishman E K, Magid D, Robertson D D et al.. Metallic hip implants: CT with multiplanar reconstruction.  Radiology. 1986;  160 675-681
• 3 Haramati N, Staron R B, Mazel-Sperling K et al.. CT scans through metal scanning technique versus hardware composition.  Comput Med Imaging Graph. 1994;  18 429-434
• 4 Chiang P P, Burke D W, Freiberg A A et al.. Osteolysis of the pelvis: evaluation and treatment.  Clin Orthop Relat Res. 2003;  (417) 164-174
• 5 DeFrang R D, Guyer W D, Porter J M et al.. Synovial cyst formation complicating total hip arthroplasty: a case report.  Clin Orthop Relat Res. 1996;  (325) 163-167
• 6 Adelman S C, Urquhart A G, Sondak V et al.. Polyethylene wear debris presenting as a retroperitoneal tumor.  Surgery. 1998;  123 111-112
• 7 Puri L, Wixson R L, Stern S H et al.. Use of helical computed tomography for the assessment of acetabular osteolysis after total hip arthroplasty.  J Bone Joint Surg Am. 2002;  84 609-614
• 8 Engh C A, Massin P, Suthers K E. Roentgenographic assessment of the biologic fixation of porous-surfaced femoral components.  Clin Orthop Relat Res. 1990;  (257) 107-128