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.