title: SEMAC-VAT MR Imaging Unravels Peri-instrumentation Lesions in Patients With Attendant Symptoms After Spinal Surgery.
abstract: The study aimed for evaluating the diagnostic value of a 2D Turbo Spin Echo (TSE) magnetic resonance (MR) imaging sequence implanted slice-encoding metal artifact correction (SEMAC) and view-angle tilting (VAT) in patients with spinal instrumentation.Sixty-seven consecutive patients with an average age of 59.7 ± 17.8 years old (range: 32-75 years) were enrolled in this study. Both sagittal, axial T1-weighted and T2-weighted MRI images were acquired with a standard TSE sequence and a high-bandwidth TSE sequence implemented the SEMAC and VAT techniques. Three continuous sections around the instrumentation in axial and sagittal images were selected for quantitative evaluation. The measurement included cumulative areas of signal void on axial images and the length of spinal canal obscuration on sagittal images. Three radiologists independently evaluated all images blindly. The inter-observer reliability was evaluated with inter-class coefficient. We defined patients with discomfortable symptoms caused by spinal instrumentation as spinal instrumentation adverse reaction.Visualizations of all periprosthetic anatomic structures were significantly better for SEMAC-VAT compared with standard imaging. For axial images, the area of signal void at the level of the instrumentation were statistically reduced with SEMAC-VAT TSE sequences than with standard TSE sequences for T2-weighted images (9.9 ± 2.6 cm vs 29.8 ± 14.7 cm, P < 0.001). For sagittal imaging, the length of spinal canal obscuration at the level of the instrumentation was reduced from 5.2 ± 2.0 cm to 1.2 ± 0.6 cm on T2-weighted images (P < 0.001), and from 4.8 ± 2.1 cm to 1.1 ± 0.5 cm on T1-weighted images with SEMAC-VAT sequences (P < 0.001). Interobserver agreement for visualization of anatomic structures and image quality was good for both SEMAC-VAT (k = 0.77 and 0.68, respectively) and standard (k = 0.74 and 0.80, respectively) imaging. The number of abnormal findings noted on SEMAC images (59 findings) was significantly higher than detected on standard images (40 findings). The incidence rate of spinal instrumentation adverse reaction was 38.81%.MR images with SEMAC-VAT can significantly reduce metal artifacts for spinal instrumentation and improve delineation of the instrumentation and periprosthetic region. Furthermore, SEMAC-VAT technique can improve diagnostic accuracy in patients with post-instrumentation spinal diseases.
authors.affiliation: From the Department of Radiology (SQ, LLG, YL, HY), Xijing Hospital, the Fourth Military Medical University, Xi'an, PR China; Department of Orthopaedics (ZGW), No. 518 Hospital of Chinese People's Liberation Army, Xi'an, PR China; Department of Orthopedics (ZGW), Lanzhou General Hospital of Lanzhou Military Region, People's Liberation Army, Lanzhou, PR China; Department of Radiotherapy (YFM), Xijing Hospital, the Fourth Military Medical University, Xi'an, PR China; Department of Radiology (SQ, JY), The First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, PR China; Siemens Healthcare (PLZ), MR Collaborations NE Asia, Beijing, PR China; Siemens Healthcare (MN), Erlangen, Germany; and Department of Orthopaedics (HQW), Xijing Hospital, The Fourth Military Medical University, Xi'an, PR China.
authors.forename: Shun
authors.initials: S
authors.lastname: Qi
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Wu
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Mu
authors.forename: Lang-Lang
authors.initials: LL
authors.lastname: Gao
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Pan-Li
authors.initials: PL
authors.lastname: Zuo
authors.forename: Mathias
authors.initials: M
authors.lastname: Nittka
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Hai-Qiang
authors.initials: HQ
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D001863:Bone Screws; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies; D013116:Spinal Cord / Q000601:surgery*; D014025:Titanium
chemical_list: D014025:Titanium