Is MRI an adequate replacement for CT scans in the three-dimensional assessment of acetabular morphology?

Abstract

Background Appropriate three-dimensional imaging of the hip joint is a substantial prerequisite for planning and performing surgical correction of deformities. Although surgeons still use computed tomography (CT), modern and fast acquisition techniques of volumetric imaging using magnetic resonance imaging (MRI) for pelvic measurements enable similar resolution. Purpose This study was designed to determine if already described measures of acetabular morphology are comparable in both techniques and if assessment can be performed with equal intra-observer and inter-observer reliability. Material and Methods Thirty-two hips (16 patients) were examined with a pelvic CT and a MRI with 3-T. Pelvic orientation was standardized by each observer in coronal, axial, and sagittal planes. Acetabular version as well as seven acetabular sector angles were measured by two observers twice with a minimum of four weeks between sessions. Results Inter-rater reliability showed excellent results for intra- and inter-rater reliability for CT (0.977-0.999) and MRI (0.969-0.998) measuring acetabular version and sector angles. Evaluating the reliability of CT and MRI for each observer revealed excellent results (0.972-0.998). Evaluating the Bland-Altman plots for intra-observer reliability showed an equal distribution of angles, within acceptable 95% limits of agreement. The same results were observed for inter-observer reliability evaluating CT and MRI as well as inter-method reliability. Conclusion Modern MRI scans are equally applicable to assess the bony pelvis as CT scans. In addition, MRI would enable the examination of soft tissues such as chondrolabral structures and muscle in the same examination. Since hip-preserving surgery is mostly conducted in younger patients, the reduction of radiation exposure is a benefit.

MRI-based static and functional assessment of complex hip deformities in comparison with CT: a validation study

“…The differences in ASA may be explained by the difficulty in differentiating between bone and labrum in MRI data, thereby leading to assumed over coverage. The mean differences of ASA were similar to the manual measurements performed by Goronzy et al [8]. Exact measurement of the alpha angle can be demanding in both CT and MRI.…”

“…These studies focused on static parameters and did not perform intermethod correlation. Goronzy et al investigated manual measurements of acetabular anteversion and coverage of the femoral head and report mean absolute differences not exceeding 0.65° ± 0.86° for inter-and intraobserver as well as intermethod comparison [8]. Chu et al compared manual and fully automatic segmentation of pelvic CT scans and found mean absolute differences of 2.0° ± 1.5° for acetabular version [14].…”

“…State-of-the-art high-resolution 3D magnetic resonance imaging (MRI) sequences fulfill these requirements and can be used to acquire imaging data for virtual motion analysis. MRI has been shown to be comparable to CT for the static measurement of the femur [7] and acetabulum [8,9]. With the advent of improved semiautomatic segmentation algorithms for volumetric MRI datasets, it has become possible to use virtual ROM analysis in clinical practice [4].…”

Development of acetabular anteversion in children with normal hips and those with developmental dysplasia of the hip: a cross-sectional study using magnetic resonance imaging

“…Although MRI is expensive and sometimes requires sedation, it is still widely used in the examination of immature hips because it does not expose children to radiation and can provide multiplanar, high-quality images that clearly show the boundaries between osseous and cartilaginous structures. A large number of anatomical and MRI studies have shown that MRI can accurately show various morphological changes of the developing hip (Goronzy et al 2019), but few studies have investigated whether MRI is reliable in measuring the OAA and CAA during development. We found excellent consistency between observers, indicating that the repeatability of MRI measurement is high.…”

“…Owing to the advantage of noninvasively distinguishing the osseous rim from the cartilaginous acetabulum in the immature hip, magnetic resonance imaging (MRI) has been widely used to evaluate the pathological abnormity of DDH (Mootha et al 2010, Krasny et al 1991, Falliner et al 2002, Douira-Khomsi et al 2010, Goronzy et al 2019. In this retrospective cross-sectional MRI study we measured OAA and CAA in children of various ages using MRI, analyzed their Background and purpose -Acetabular anteversion (AA) is related to hip function.…”