Diagnosis of Chronic Hip Pain After Total Hip Arthroplasty Using SEMAC-VAT MR Imaging
Yimin Ma1, Panli Zuo2, Mathias Nittka3, and Xiaoguang Cheng4

1Department of radiology, Department of radiology, Jishuitan Hospital, Beijing, China, Beijing, China, China, People's Republic of, 2Siemens Healthcare, MR Collaborations NE Asia, Beijing, China, Beijing, China, China, People's Republic of, 3Siemens Healthcare, Erlangen, Germany, Erlangen, Germany, 4Department of Radiology, Department of Radiology, Jishuitan Hospital, Beijing, China, Beijing, China, China, People's Republic of

Synopsis

With the rapid development of medicine technology, total hip arthroplasty (THA) is now widely used in the treatment of endstage hip osteoarthritis, severe hip fracture, hip bone tumor, and so forth. THA can relieve hip pain and improve the activity of the joints, while it still brings some unexpected complications, such as periprothesis bone resorption, periprothesis fractures, and metallic implants dislocation. Since then, distortion-free MRI near metal, like SEMAC-VAT MR, has shown its great clinical potential in diagnosing patients treated with THA.

Purpose

The purpose of this study was to compare the metal artifact area and the definition of periprosthesis structures between SEMAC-VAT TSE and standard TSE MR imaging in patients with chronic hip pain after total hip arthroplasty (THA), and to interpret the possible causes of chronic hip pain in patients after THA using MR imaging, digital radiography (DR) imaging, and pathology finding.

Materials and methods

A total number of 17 patients (8 males and 9 females; mean age, 54.6±12.9 years; age range, 29-79 years) with 11 unilateral and 6 bilateral THA were enrolled in this study. All patients suffered chronic post-THA hip pain for more than 3 months. MR imaging was performed on a 1.5T MR scanner (MAGNETOM Espree, Siemens Healthcare, Erlangen, Germany) with standard and SEMAC-VAT TSE sequences including coronal and axial T1-weighted imaging (TE/TR, 16/484ms; FOV, 380´380 mm2; FA, 150°; matrix, 320´320; slice thickness, 4.0 mm), coronal and axial T2-weighted TIRM imaging (TE/TR, 51/7450 ms; FOV, 380´380 mm2; FA, 150°; matrix, 320´320; slice thickness, 4.0 mm). For SEMAC, 6 encoding steps were used. All patients also underwent DR examination. Two radiologists independently measured the area of metal artifact, evaluated the definition of acetabulum zone and femur zone on 3 score, and interpreted the possible causes of chronic pain based on MR imaging, DR imaging, and pathology findings.

Results

The area of metal artifact was significantly reduced in SEMAC-VAT compared with standard TSE images (Table 1). The qualitative score was also higher in SEMAC-VAT compared with standard TSE images (Table 2). Figure 1 shows an example case of intraoperatively confirmed periprosthetic bone resorption both positive on MR imaging and DR imaging; Figure 2 shows an example case of periprosthetic bone resorption positive on MR imaging but negative on DR imaging; Figure 3 shows an example of pathologically confirmed adverse local tissue reaction positive on MR imaging but negative on DR imaging. In 17 THA patients, 16 patients showed positive in diagnosis on SEMAC-VAT images with the following findings: 1 adverse local tissue reaction (0 in DR), 1 synovitis (0 in DR), 3 periprosthetic bone resorption (2 in DR), 3 synovial-like membrane surrounding the prosthesis (2 in DR), 7 hip muscle atrophy or edema (0 in DR), 8 synovial hyperplasia (0 in DR) and 11 osseous stress reactions (0 in DR).

Conclusion

Compared to standard TSE, SEMAC-VAT TSE significantly reduced metal artifact and accurately detected many positive findings in post-THA patients that were missing in DR imaging.

Acknowledgements

No acknowledgement found.

References

No reference found.

Figures

Tab. 1 Standard TSE compared with SEMAC-VAT TSE, ***p <0.001 for all.

Tab. 2 0 for severe metal artifacts with no delineation of prosthesis; 1 for blur in periprosthesis structures; 2 for clear delineation of prosthesis with good imaging of periprosthesis structures. ***p <0.001 for all.

Figure 1. Female, 56 years old, with right hip of THA. (A) T1-weighted SEMAC-VAT image shows low-single band at the interface of bone and implant (arrow); (B) T2-TIRM-weighted SEMAC-VAT image shows high-single band at the interface of bone and implant (arrow); (C) DR image shows light line surrounding implant.

Figure 2. Male, 73 years old, with right hip of THA. (A) T1-weighted SEMAC-VAT image shows low-single band at the interface of bone and implant (arrow); (B) T2-TIRM-weighted SEMAC-VAT image shows high-single band at the interface of bone and implant (arrow); (C) DR image does not show significant light line surrounding implant.

Figure 3. Male, 49 years old, with left hip of THA. (A) T1-weighted SEMAC-VAT image shows non-uniform signals in the soft tissue (arrow); (B) T2-TIRM-weighted SEMAC-VAT image shows high-single at the soft tissue (arrow); (C) DR image shows no signal; (D) pathological findings show fibrous hyperplasia and metallic particles (arrow).



Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)
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