MR arthrography of the shoulder: evaluation of isotropic 3D intermediate-weighted FSE and hybrid GRE T1-weighted sequences

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Dual-Energy CT Arthrography: Advanced Muscolo-Skelatal Applications in Clinical Practice

This paper provides a comprehensive overview of the potential applications of dual-energy CT (DECT) in improving image quality and the diagnostic capabilities of CT arthrography (CTA) in clinical practice. The paper covers the use of virtual non-contrast (VNC) images, in which the injected contrast medium is subtracted from the articular cavity in order to better analyze 2D and 3D images of the bone. Moreover, virtual monoenergetic imaging (VMI) applications and their potential use for the reduction of metal artifacts and improving image contrast are reviewed. The role of virtual non-calcium (VNCa) in detecting bone marrow edema surrounding the imaged joint will be discussed. Furthermore, the role of iodine maps in enhancing the contrast between soft tissues, optimizing the visualization of contrast material, and distinguishing contrast material from calcifications is described. Finally, a case series including different joints is provided to underline the additional advantages of high-spatial-resolution dual-energy CT reconstructed images.

Detecting Rotator Cuff Tears: A Network Meta-analysis of 144 Diagnostic Studies

BACKGROUND

Many imaging techniques have been developed for the detection of rotator cuff tears (RCTs). Despite numerous quantitative diagnostic studies, their relative accuracy remains inconclusive.

PURPOSE

To determine which of 3 commonly used imaging modalities is optimal for the diagnosis of RCTs.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Studies evaluating the performance of magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA), and ultrasound (US) used in the detection of RCTs were retrieved from the PubMed/MEDLINE and Embase databases. Diagnostic data were extracted from articles that met the inclusion/exclusion criteria. A network meta-analysis was performed using an arm-based model to pool the absolute sensitivity and specificity, relative sensitivity and specificity, and diagnostic odds ratio as well as the superiority index for ranking the probability of these techniques.

RESULTS

A total of 144 studies involving 14,059 patients (14,212 shoulders) were included in this network meta-analysis. For the detection of full-thickness (FT) tears, partial-thickness (PT) tears, or any tear, MRA had the highest sensitivity, specificity, and superiority index. For the detection of any tear, MRI had better performance than US (sensitivity: 0.84 vs 0.81, specificity: 0.86 vs 0.82, and superiority index: 0.98 vs 0.22, respectively). With regard to FT tears, MRI had a higher sensitivity and superiority index than US (0.91 vs 0.87 and 0.67 vs 0.28, respectively) and a similar specificity (0.88 vs 0.88, respectively). The results for PT tears were similar to the detection of FT tears. A sensitivity analysis was performed by removing studies involving only 1 arm for FT tears, PT tears, or any tear, and the results remained stable.

CONCLUSION

This network meta-analysis of diagnostic tests revealed that high-field MRA had the highest diagnostic value for detecting any tear, followed by low-field MRA, high-field MRI, high-frequency US, low-field MRI, and low-frequency US. These findings can help guide clinicians in deciding on the appropriate imaging modality.

Evaluation of glenoid labral tears: comparison between dual-energy CT arthrography and MR arthrography of the shoulder

OBJECTIVE

To compare the diagnostic accuracy of dual-energy computed tomography arthrography (DE-CTA) and magnetic resonance arthrography (MRA) of the shoulder in depicting glenoid labral tears.

METHODS

This prospective institutional review board-approved study included 47 consecutive patients (28 males, 19 females; mean age of 34.2 years) studied between January 2017 and October 2018. All patients underwent DE-CTA and MRA the same day. Two radiologists (25 and 11 years of experience, respectively), blinded to clinical data, evaluated the presence labral tears on virtual-blended 120 kV standard CTA and on DE-CTA images. A third radiologist (18 years of experience) evaluated the MRA images. Diagnostic accuracy values were calculated by using surgery as standard of reference. Inter-observer and intra-observer agreements were calculated with k statistics. A value of p < 0.05 was considered statistically significant.

RESULTS

Surgery revealed the presence of labral tears in 38/47 patients (80.9%). Sensitivity and specificity values in diagnosing labral tears were 84.2% and 77.8% for MRA (Reader 3), 84.2% and 77.8% for CTA (Reader 1), 84.2% and 88.9% for CTA (Reader 2), 89.5% and 88.9% for DE-CTA (Reader 1), and 92.1% and 88.9% for DE-CTA (Reader 2). A nonsignificant increase in AUC values with respect to MRA was obtained by reading the CTA (p = 0.470) and DE-CTA dataset (p = 0.217), respectively. Inter-observer agreements were near perfect for CTA (k = 0.84) and substantial for DE-CTA reading (k = 0.76). Intra-observer agreements were near perfect both for CTA (k = 0.88) and for DE-CTA reading (k = 0.82).

CONCLUSION

DE-CTA and MRA were not different in terms of diagnostic performance.

Diagnostic performance of shoulder magnetic resonance arthrography for labral tears having surgery as reference: comparison of high-resolution isotropic 3D sequence (THRIVE) with standard protocol

PURPOSE

To compare the diagnostic performance of T1 high-resolution isotropic volume excitation (THRIVE) sequence with that of a standard protocol for direct shoulder magnetic resonance arthrography (MRA) for the diagnosis of superior labral anterior-to-posterior (SLAP) and Bankart lesions, using arthroscopy findings as a reference standard.

MATERIALS AND METHODS

We retrospectively studied 84 patients who underwent direct shoulder 3T MRA using THRIVE and two-dimensional three-plane proton-density fat-suppressed (2D-PD-FS) sequences. One reviewer evaluated the contrast-to-noise ratio (CNR) as a quantitative image quality. Other two reviewers independently evaluated the subjective image noise, image sharpness, and radiologic diagnosis as qualitative image quality. Arthroscopic surgical findings were considered the reference standard. Wilcoxon rank sum, Chi-square/Fisher's exact, and DeLong's tests, as well as intraclass correlation coefficients (ICCs) were used to evaluate differences between THRIVE and 2D-PD-FS images.

RESULTS

THRIVE images had significantly higher CNR (p < 0.001), and subjective ratings of image noise (p = 0.009) and sharpness (p = 0.039) than 2D-PD-FS images (p < 0.001). THRIVE images had similar (p ≥ 0.18) diagnostic performance (sensitivity, 93.0-97.2%; specificity, 95.8-100%; accuracy, 95.2-97.6%) for the diagnosis of SLAP and Bankart lesions with excellent agreement (ICC = 0.898-0.942) when compared to 2D-PD-FS images (sensitivity, 86.1-91.7%; specificity, 93.8-95.8%; accuracy, 90.5-92.9%; agreement, ICC = 0.782-0.858). The scan time was reduced by 69% for THRIVE sequence compared to 2D-PD-FS sequence (2 min 40 s vs. 8 min 40 s).

CONCLUSION

The THRIVE sequence may be helpful in the diagnosis of SLAP and Bankart lesions, and may be routinely used during direct shoulder 3T MRA.