Comparison of MR Ultrashort Echo Time and Optimized 3D‐Multiecho In‐Phase Sequence to Computed Tomography for Assessment of the Osseous Craniocervical Junction

Abstract

Background To assess changes of the craniocervical junction (CCJ), computed tomography (CT) is considered the reference standard. Recent advances in bone depiction on magnetic resonance imaging (MRI) enable high‐quality visualization of osseous structures. Consequently, MRI may serve as an alternative to CT, without the use of ionizing radiation. Purpose To compare two MRI sequences optimized for bone visualization to the CT reference standard in the assessment of the osseous CCJ. Study Type Prospective. Population/Subjects Twenty‐seven decedents and five healthy volunteers. Field Strength/Sequence 3T/ultrashort‐echo time gradient echo (UTE) and optimized 3D‐multiecho in‐phase gradient echo sequences (FRACTURE). Assessment All decedents were scanned with both MRI sequences and CT. Three observers rated degeneration to obtain a score for the upper (atlanto‐dental and left/right atlanto‐occipital joint) and for the lower part of the CCJ (left and right atlanto‐axial joint). Two reader rated the following quantitative parameters: basion‐axial‐interval, atlanto‐dental‐interval, atlanto‐occipital‐interval, Powers‐ratio, and signal/contrast‐to‐noise‐ratio. As a proof of concept, five healthy volunteers were scanned with both MRI sequences. Statistical Tests Degeneration was assessed on a Likert scale by three independent observers. Interrater and intermodality reliability were calculated using an intraclass correlation coefficient. To compare distance measurements between examination methods, a Friedman test, between‐degenerative ratings, and a Kruskal–Wallis test were performed. Results Degenerative ratings of the CCJ between MRI sequences and CT showed a good interrater and intermodality agreement. MRI sequences tended to underestimate the degree of degeneration compared to CT, and this became more marked with increasing degeneration severity. There were no significant relationships between distance measurements and the degree of degeneration (PCT = 0.62, PUTE = 0.64, PFRACTURE = 0.67). The in vivo examination proved the feasibility of both MRI methods in a clinical setting. Data Conclusion Quantitative and qualitative ratings on MR images were comparable to CT images; thus, MRI may be a valid alternative to CT assessing the CCJ. Level of Evidence 1. Technical Efficacy Stage 3.

Magnetic Resonance Imaging Versus Computed Tomography for Three‐Dimensional Bone Imaging of Musculoskeletal Pathologies: A Review

“…For intervertebral disc heights, limits of agreement of ±2–3 mm were reported between S‐GRE and CT images and of ±4 mm between UTE and CT images 36 . Similarly, CT/UTE intermodal limits of agreements were within ±1 mm for the distance between the cranium and C1 and within ±2–4 mm between the cranium and C2 55 . However, these intermodal differences in the distances between the cranium and cervical spine were not significant and may partly originate from the differences in resolution between MR (0.8 mm × 0.8 mm × 1.2 mm) and CT (<0.6 mm × 0.6 mm × 0.6 mm).…”

“…In these cases, MRI is suitable for detecting ligamentous or intervertebral disc pathologies whereas CT can detect stenosis of the cervical spinal canal or neuroforamina 5 . In both the craniocervical junction and cervical spine, degenerative changes were graded with good intermodal agreement, 5,55 similar to the interobserver agreement on CT 5 . This was facilitated by multiplanar reformatting possible on isotropic ZTE images 5 .…”

“…In addition, uncontrolled motion was seen in the spine, 36 and the jaw, 53 and is common in clinical care of the shoulder, weakening the diagnostic power of MRI. Nonetheless, motion artifacts can be reduced by using motion insensitive acquisition methods, including breath holds, 67 interleaved scanning, increased parallel imaging with higher signal averaging, or radial sampling of the k‐space 21,55,64,70 …”

“…39 For diagnosing sclerosis, GRE images seemed superior to UTE images 36 or SE images as seen in the sacroiliac joint. 42,92 Other structural anomalies, including degenerative changes in the craniocervical junction 55 and in the cervical spine 5 that can cause neck pain were also investigated. In these cases, MRI is suitable for detecting ligamentous or intervertebral disc pathologies whereas CT can detect stenosis of the cervical spinal canal or neuroforamina.…”

“…Nonetheless, motion artifacts can be reduced by using motion insensitive acquisition methods, including breath holds, 67 interleaved scanning, increased parallel imaging with higher signal averaging, or radial sampling of the k-space. 21,55,64,70 SUSCEPTIBILITY ARTIFACTS. MRI can also be impaired by magnetic susceptibility-related distortions due to the shape of the body, or the presence of air or of implanted devices.…”