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The critical shoulder angle (CSA) was measured by identifying the superior and inferior corners of the lateral glenoid joint face and the lateral edge of the acromion on (A) Grashey view radiographs and (B) 3-dimensional, zero echo time (ZTE), magnetic resonance image (MRI) scans with 20 mm-thick, coronal oblique reformatted, inverted minimum intensity projection. Note that both measurements are similar (34.0 vs 34.4 ) in this patient (the ratio of the transverse to longitudinal diameter of the lateral glenoid outline was 0.06). During measurement, the anatomic landmarks of the CSA were cross-referenced on ZTE MRI scans: (C) sagittal oblique (white dots mark superior and inferior glenoid corners) and (D) transverse (white dot marks lateral edge of the acromion). The sagittal oblique ZTE image in (C) was derived from reformatting according to (E) coronal and (F) axial ZTE images, which ensures the most accurate depiction of the lateral glenoid joint face. The blue lines in (E) and (F) show the orientation of (C).
Source publication
Background
Suboptimal positioning on Grashey view radiographs may limit the prognosticating potential of the critical shoulder angle (CSA) for shoulder disorders.
Purpose
To investigate whether radiography optimized according to the latest research is reliable for measuring CSA in comparison with magnetic resonance imaging (MRI) featuring 3-dimens...
Contexts in source publication
Context 1
... observers (a third-year radiology resident and a radiologist with 3 years of dedicated musculoskeletal imaging experience after the residency (Y.Y. and A.E.Y. respectively) independently measured the CSA on both the Grashey view radiographs ( Figure 3A) and the ZTE images that entailed 20 mm-thick, coronal oblique reformatted, inverted minimum intensity projection ( Figure 3B); for the latter, the measurement points were verified by crossreferencing on images from other planes (Figure 3, C-F). The obliquity of coronal ZTE reformats was determined on a virtual workstation such that the resultant images were perpendicular to the glenohumeral joint face of the scapula on the axial plane and parallel to the longitudinal axis of the lateral glenoid joint face on the sagittal plane ( Figure 3, B, E, and F). ...
Context 2
... observers (a third-year radiology resident and a radiologist with 3 years of dedicated musculoskeletal imaging experience after the residency (Y.Y. and A.E.Y. respectively) independently measured the CSA on both the Grashey view radiographs ( Figure 3A) and the ZTE images that entailed 20 mm-thick, coronal oblique reformatted, inverted minimum intensity projection ( Figure 3B); for the latter, the measurement points were verified by crossreferencing on images from other planes (Figure 3, C-F). The obliquity of coronal ZTE reformats was determined on a virtual workstation such that the resultant images were perpendicular to the glenohumeral joint face of the scapula on the axial plane and parallel to the longitudinal axis of the lateral glenoid joint face on the sagittal plane ( Figure 3, B, E, and F). ...
Context 3
... observers (a third-year radiology resident and a radiologist with 3 years of dedicated musculoskeletal imaging experience after the residency (Y.Y. and A.E.Y. respectively) independently measured the CSA on both the Grashey view radiographs ( Figure 3A) and the ZTE images that entailed 20 mm-thick, coronal oblique reformatted, inverted minimum intensity projection ( Figure 3B); for the latter, the measurement points were verified by crossreferencing on images from other planes (Figure 3, C-F). The obliquity of coronal ZTE reformats was determined on a virtual workstation such that the resultant images were perpendicular to the glenohumeral joint face of the scapula on the axial plane and parallel to the longitudinal axis of the lateral glenoid joint face on the sagittal plane ( Figure 3, B, E, and F). ...
Context 4
... observers (a third-year radiology resident and a radiologist with 3 years of dedicated musculoskeletal imaging experience after the residency (Y.Y. and A.E.Y. respectively) independently measured the CSA on both the Grashey view radiographs ( Figure 3A) and the ZTE images that entailed 20 mm-thick, coronal oblique reformatted, inverted minimum intensity projection ( Figure 3B); for the latter, the measurement points were verified by crossreferencing on images from other planes (Figure 3, C-F). The obliquity of coronal ZTE reformats was determined on a virtual workstation such that the resultant images were perpendicular to the glenohumeral joint face of the scapula on the axial plane and parallel to the longitudinal axis of the lateral glenoid joint face on the sagittal plane ( Figure 3, B, E, and F). We decided to use the 20 mm on coronal oblique ZTE reformats after measuring the projectional distance between the lateral rim of the acromion and the superior corner of the glenoid cavity on 10 patients (outside the study group with similar demographic and clinical characteristics). ...
Citations
... Benefits of ZTE application in shoulder MRI were previously demonstrated, with strong inter-modality agreements between CT and ZTE images [9][10][11]. As an inherently 3D volume technique, ZTE also accommodates multiplanar reformations and maximum intensity projection renderings, like CT. ...
Objectives
To assess a deep learning-based reconstruction algorithm (DLRecon) in zero echo-time (ZTE) MRI of the shoulder at 1.5 Tesla for improved delineation of osseous findings.
Methods
In this retrospective study, 63 consecutive exams of 52 patients (28 female) undergoing shoulder MRI at 1.5 Tesla in clinical routine were included. Coronal 3D isotropic radial ZTE pulse sequences were acquired in the standard MR shoulder protocol. In addition to standard-of-care (SOC) image reconstruction, the same raw data was reconstructed with a vendor-supplied prototype DLRecon algorithm. Exams were classified into three subgroups: no pathological findings, degenerative changes, and posttraumatic changes, respectively. Two blinded readers performed bone assessment on a 4-point scale (0-poor, 3-perfect) by qualitatively grading image quality features and delineation of osseous pathologies including diagnostic confidence in the respective subgroups. Quantitatively, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of bone were measured. Qualitative variables were compared using the Wilcoxon signed‐rank test for ordinal data and the McNemar test for dichotomous variables; quantitative measures were compared with Student’s t -testing.
Results
DLRecon scored significantly higher than SOC in all visual metrics of image quality (all, p < 0.03), except in the artifact category ( p = 0.37). DLRecon also received superior qualitative scores for delineation of osseous pathologies and diagnostic confidence ( p ≤ 0.03). Quantitatively, DLRecon achieved superior CNR (95 CI [1.4–3.1]) and SNR (95 CI [15.3–21.5]) of bone than SOC ( p < 0.001).
Conclusion
DLRecon enhanced image quality in ZTE MRI and improved delineation of osseous pathologies, allowing for increased diagnostic confidence in bone assessment.
... Later studies supported this proposition, and some studies that refuted it likely performed inaccurate measurement of CSA owing to positional variability associated with the Grashey view (34,35). By using the ZTE sequence for CSA measurement, we showed in a recent study that more stringent measures needed to be used in the quality check of Grashey views (36). In fact, the ZTE sequence can be used as a proxy for the Grashey view for CSA measurement in patients with shoulder problems, many of whom are scheduled for MRI examinations already (36) (Fig E1). ...
Zero echo time (ZTE) imaging is an MRI technique that produces images similar to those obtained with radiography or CT. In ZTE MRI, the very short T2 signal from the mineralized trabecular bone matrix and especially cortical bone-both of which have a low proton density (PD)-is sampled in a unique sequence setup. Additionally, the PD weighting of the ZTE sequence results in less contrast between soft tissues. Therefore, along with gray-scale inversion from black to white and vice versa, ZTE imaging provides excellent contrast between cortical bone and soft tissues similar to that of radiography and CT. However, despite isotropic or near-isotropic three-dimensional (3D) imaging capabilities of the ZTE sequence, spatial resolution in this technique is still inferior to that of radiography and CT, and 3D volume renderings are currently time-consuming and require postprocessing software that features segmentation and manual contouring. Optimization of ZTE MRI mostly entails adjustments of bandwidth, flip angle, field of view, and image matrix. A wide range of structural abnormalities and disease or healing processes in the musculoskeletal system are well delineated with ZTE MRI, including conditions that involve bone-based morphometric analyses (which aid diagnosis, help prognostication, and guide surgery), impaction, avulsion and stress fractures, loose bodies or erosions in and around joints, soft-tissue calcifications and ossifications, and bone tumors (including treatment response). The pitfalls of ZTE imaging include mimics of foci of calcification or ossification such as intra-articular gas and susceptibility artifacts from surgical materials and hemosiderin deposition, which can be avoided in many instances by cross-referencing images obtained with other MRI sequences. Online supplemental material is available for this article. ©RSNA, 2022.
The introduction of new ultrashort and zero echo time (ZTE) sequences is revolutionizing magnetic resonance imaging (MRI) and optimizing patient management. These sequences acquire signals in tissues with very short T2: mineralized bone, cortical bone, and calcium deposits. They can be added to a classic MRI protocol. ZTE MRI provides computed tomography–like contrast for bone.
Background:
The amount of glenoid width that must be restored with a Latarjet procedure in order to reestablish glenohumeral stability has not been determined.
Purpose/hypothesis:
The purpose of this article was to determine the percentage of glenoid width restoration necessary for glenohumeral stability after Latarjet by measuring anterior humeral head translation and force distribution on the coracoid graft. The hypothesis was that at least 100% of glenoid width restoration with Latarjet would be required to maintain glenohumeral stability.
Study design:
Controlled laboratory study.
Methods:
Nine cadaveric shoulders were prepared and mounted on an established shoulder simulator. A lesser tuberosity osteotomy (LTO) was performed to allow accurate removal of glenoid bone. Coracoid osteotomy was performed, and the coracoid graft was sized to a depth of 10 mm. Glenoid bone was sequentially removed, and Latarjet was performed using 2 screws to reestablish 110%, 100%, 90%, and 80% of native glenoid width. The graft was passed through a subscapularis muscle split, and the LTO was repaired. A motion tracking system recorded glenohumeral translations, and force distribution was recorded using a TekScan pressure sensor secured to the glenoid face and coracoid graft. Testing conditions included native; LTO; Bankart tear; and 110%, 100%, 90%, and 80% of glenoid width restoration with Latarjet. Glenohumeral translations were recorded while applying an anteroinferior load of 44 N at 90° of humerothoracic abduction and 0° or 45° of glenohumeral external rotation. Force distribution was recorded without an anteroinferior load.
Results:
Anterior humeral head translation progressively increased as the proportion of glenoid width restored decreased. A marked increase in anterior humeral head translation was found with 90% versus 100% glenoid width restoration (10.8 ± 3.0 vs 4.1 ± 2.6 mm, respectively; P < .001). Greater glenoid bone loss also led to increased force on the coracoid graft relative to the native glenoid bone after Latarjet. A pronounced increase in force on the coracoid graft was seen with 90% versus 100% glenoid width restoration (P < .001).
Conclusion:
Anterior humeral head translation and force distribution on the coracoid graft dramatically increased when <100% of the native glenoid width was restored with a Latarjet procedure.
Clinical relevance:
If a Latarjet is unable to fully restore the native glenoid width, surgeons should consider alternative graft sources to minimize the risk of recurrent instability or coracoid overload.
