The combined use of shoulder arthrography with MR and CT imaging offers distinct advantages over conventional nonarthrographic imaging techniques. The improved contrast and joint distension afforded by direct arthrography optimize evaluation of various intra-articular structures and help to define subtle abnormalities and distinguish normal variants from true shoulder pathology. In this article, we review the rationale and basic approaches to shoulder arthrography as well as the imaging appearance of the normal shoulder, anatomical variants, and pathology highlighted by this technique.
"Preoperative imaging is essential to obtain a detailed description of possible lesions with excellent delineation of the anterior labrum and associated glenohumeral ligament complex [7–9]. Computed tomography (CT) and CT arthrography are optimal in the quantification of glenoid bony lesions (bony Bankart) or fractures of the humeral head (Hill-Sachs), but show several limitations in the evaluation of muscles and tendons [10, 11]. "
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: To evaluate the diagnostic performance of magnetic resonance (MR) arthrography of the shoulder in the diagnosis of anteroinferior labrum lesions, using arthroscopy as the reference standard and to classify these lesions. METHODS: Institutional review board approval was obtained. The study population included 59 consecutive patients with history and clinical diagnosis of acute or chronic anterior shoulder instability. A total of 62 MR arthrograms were performed, since three patients had undergone a bilateral procedure. Arthroscopy, which was performed within a mean of 3 months (range 2-5 months) after MR arthrography, was used as the reference standard. Sensitivity, specificity, accuracy, positive and negative predictive values were then calculated. RESULTS: MR arthrography showed a sensitivity of 96 % and a specificity of 80 % for the overall detection of anteroinferior labrum abnormalities. The diagnostic accuracy was 95 % and the positive and negative predictive values were 98 % and 66 % respectively. Ten lesions were non-classifiable on surgery, of which eight were non classifiable on MR arthrography also. CONCLUSIONS: MR arthrography is highly accurate for the detection and classification of shoulder anteroinferior labrum lesions. Shoulder surgeons can confidently rely on this method to determine which patients will benefit from arthroscopy. MAIN MESSAGES : • MR arthrography is accurate for the detection and classification of shoulder labrum lesions. • MR arthrography is a valuable tool for the preoperative planning in acute or chronic instability. • Shoulder surgeons can rely on this method to determine which patients will benefit from arthroscopy.
Insights into Imaging 02/2013; 4(2). DOI:10.1007/s13244-013-0225-0
[Show abstract][Hide abstract] ABSTRACT: Objectives:
The objectives of this study were to analyze the spatial resolution of different reconstruction kernels and acquisition protocols, including a prototypic high-resolution protocol in flat-panel (FP) and multidetector (MD) computed tomography (CT), and to evaluate contrast and artificial cartilage depiction quality of in vitro FPCT and MDCT arthrography.
Materials and methods:
An image-quality cone beam phantom was used to compare resolution and different reconstruction kernels of the standard MDCT (120 and 80 kV) and the standard binned (2 × 2) and prototypic high-resolution unbinned (1 × 1) FPCT protocols (5- and 20-second runs each). With the resulting FPCT kernel best matching the standard MDCT kernel (U90u), artificial joint phantoms with differently sized groups of cartilage defects (2, 1, 0.5, and 0.3 mm in width) were then scanned using intra-articular iodinated contrast at 50 mgI/mL. In these joint phantoms, CT numbers and noise in the iodinated contrast and artificial cartilage tissue were measured and contrast-to-noise ratios (CNR) were calculated. Depiction quality of artificial cartilage defects was qualitatively rated by 2 independent radiologists.
A sharp reconstruction kernel for all FPCT protocols suited best for matched resolution to the standard MDCT kernel. High-resolution 20-second 1 × 1 binning FPCT showed comparable resolution with MDCT in the range of 0.4 to 1.6 line pairs (lp) per millimeter with superior resolution in higher frequencies than 1.6 lp per millimeter (P < 0.001). Flat-panel computed tomographic 5-second runs were associated with higher image noise than the 20-second runs were. The CNR differed significantly among the protocols (P < 0.01) and was the highest in the 20-second FPCT, followed by the 5-second FPCT 2 × 2 and MDCT protocols. Interreader agreement for the depiction quality of artificial cartilage defects was substantial and high in the joint phantoms (0.74 and 0.81, respectively; P < 0.001). The best ratings of the artificial cartilage defect depiction quality were seen in the FPCT 20-second, followed by the FPCT 5-second and MDCT acquisitions. The depiction quality of smaller cartilage defects (1.0 and 1.67 lp per millimeter) was rated worst in the MDCT acquisitions.
In vitro FPCT arthrography offers superior CNR and artificial cartilage defect depiction quality to MDCT, and spatial resolution for small structures is higher when applying high-resolution acquisition protocols. Flat-panel computed tomography, thus, has the potential to improve workflow, and tailored high-resolution protocols may allow for advanced cartilage evaluation in CT arthrography.
[Show abstract][Hide abstract] ABSTRACT: Direct MR arthrography of the shoulder is a safe, relatively easy procedure that can increase diagnostic confidence in the evaluation of rotator cuff and labroligamentous disorders compared with conventional MR imaging of the shoulder. Surgeons more often request MR arthrography in younger patients who may have internal impingement or subtle shoulder subluxation rather than obvious cuff rupture, repeated dislocation, or arthropathy. This article describes the advances in glenohumeral injection and MR protocol techniques, imaging pitfalls, anatomical variants, common lesions associated with internal derangement of the shoulder, and MR arthrography of the postoperative shoulder.
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