Indirect magnetic resonance arthrography: applications in sports imaging

[Current MR imaging of cartilage in the context of knee osteoarthritis (part 1) : Principles and sequences]

Magnetic resonance imaging (MRI) is the clinical method of choice for cartilage imaging in the context of degenerative and nondegenerative joint diseases. The MRI-based definitions of osteoarthritis rely on the detection of osteophytes, cartilage pathologies, bone marrow edema and meniscal lesions but currently a scientific consensus is lacking. In the clinical routine proton density-weighted, fat-suppressed 2D turbo spin echo sequences with echo times of 30-40 ms are predominantly used, which are sufficiently sensitive and specific for the assessment of cartilage. The additionally acquired T1-weighted sequences are primarily used for evaluating other intra-articular and periarticular structures. Diagnostically relevant artifacts include magic angle and chemical shift artifacts, which can lead to artificial signal enhancement in cartilage or incorrect representations of the subchondral lamina and its thickness. Although scientifically validated, high-resolution 3D gradient echo sequences (for cartilage segmentation) and compositional MR sequences (for quantification of physical tissue parameters) are currently reserved for scientific research questions. The future integration of artificial intelligence techniques in areas such as image reconstruction (to reduce scan times while maintaining image quality), image analysis (for automated identification of cartilage defects), and image postprocessing (for automated segmentation of cartilage in terms of volume and thickness) will significantly improve the diagnostic workflow and advance the field further.

ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update

Chronic hip pain is a frequent chief complaint for adult patients who present for evaluation in a variety of clinical practice settings. Following a targeted history and physical examination, imaging plays a vital role in elucidating the etiologies of a patient's symptoms, as a wide spectrum of pathological entities may cause chronic hip pain. Radiography is usually the appropriate initial imaging test following a clinical examination. Depending on the clinical picture, advanced cross-sectional imaging may be subsequently performed for further evaluation. This documents provides best practice for the imaging workup of chronic hip pain in patients presenting with a variety of clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. While radiographs remain the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This review leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR angiography, as well as imaging evaluation of the postoperative rotator cuff, are also considered. Through careful selection among the available imaging modalities, as well as optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Magnetic resonance-guided interventions of large and small joints

Magnetic resonance (MR)-guided interventions of large and small joints are feasible and safe procedures offering several advantages compared with standard guiding techniques. Nevertheless, MR-guided interventions are not routinely performed in daily practice apart from a few centers. Accurate injections are crucial for clinical outcome in diagnostic arthrography as well as therapeutic joint injections. In particular, palpatory joint puncture was shown to be inaccurate or uncertain in a substantial percentage of injections of the shoulder, the hip, and the knee. Magnetic resonance imaging offers respective merits of a cross-sectional technique with high soft-tissue contrast. Exact depiction of structures, which should be preserved, such as the labrum, should be aimed for. Areas with complex anatomy can be approached by adapting the right imaging plane(s) because of multiplanar capacity. Lack of ionizing radiation for patients is of growing interest particularly in young patients with repeated interventions. Magnetic resonance guidance alone allows an "all-in-one" MR arthrography combining precise targeting with high-field-strength imaging. Modern short-bore and open-bore high-field-strength systems offer a good comfort for patients as well as clinicians and enhance patient positioning options such as supine or prone position. Thus, a tailored approach such as a posterior technique for suspected anterior lesions in shoulder MR arthrography is possible.In this article, we describe the advantages and limitations of MR guidance in joint interventions with focus on shoulder and hip interventions. We review the requirements for needle material and MR sequences, discuss several different techniques developed to date, and present current results in clinical outcome.

MRI image overlay: Application to arthrography needle insertion

Magnetic Resonance Imaging (MRI) offers great potential for planning, guiding, monitoring and controlling interventions. MR arthrography (MRAr) is the imaging gold standard for assessing small ligament and fibrocartilage injury in joints. In contemporary practice, MRAr consists of two consecutive sessions: (1) an interventional session where a needle is driven to the joint space and MR contrast is injected under fluoroscopy or CT guidance; and (2) a diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space and evaluate the condition of the joint. Our approach to MRAr is to eliminate the separate radiologically guided needle insertion and contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners. We propose a 2D augmented reality image overlay device to guide needle insertion procedures. This approach makes diagnostic high-field magnets available for interventions without a complex and expensive engineering entourage. In preclinical trials, needle insertions have been performed in the joints of porcine and human cadavers using MR image overlay guidance; in all cases, insertions successfully reached the joint space on the first attempt.

MR arthrography of the ankle: indications and technique

MR arthrography has become an important tool for the assessment of a variety of ankle disorders. MR arthrography permits more sensitive imaging of suspected intra-articular pathology in cases in which conventional MR imaging is either insufficient or inadequate for diagnosis or treatment planning. The main indications for MR arthrography are the evaluation of ligamentous injuries, impingement syndromes, cartilage lesions, osteochondral lesions of the talus, loose bodies, and several synovial joint disorders. Indirect MR arthrography can be a useful adjunct to conventional MR imaging and may be preferable to direct MR arthrography in those cases in which an invasive procedure is contraindicated or image guidance is not available.

Modern imaging of the hand, wrist, and forearm

A review of the current state of the relevant diagnostic imaging technologies and methods and their clinical application in imaging common conditions of the hand, wrist, and forearm is presented. Evolving and future imaging technologies are also considered.

Técnica e indicaciones de la resonancia magnética artrografía. Extremidad superior (I)

Magnetic resonance (MR) is the most effective imaging technique in the diagnosis of articular pathology. MR arthrography (MRA), with intra-articular injection of diluted gadolinium or physiological saline solution has become more common in recent years. The intra-articular fluid facilitates the detection of articular pathology by delineating the articular structures, separating adjacent anatomic structures, and filling potential spaces that originate in or communicate with the joint. MRA provides additional information about the integrity of the articular structures, especially cartilage, fibrocartilage, and ligaments. MRA has proven especially useful in the shoulder, where most of the studies have been centered. The detection of subtle lesions of the capsule/labrum complex is fundamental for presurgical evaluation. MRA can be used to complement conventional MR imaging in some cases and in others it is the initial technique of choice. Indirect MRA with intravenous gadolinium administration is based on the enhancement of articular fluid caused by diffusion from the synovial space to the articular space. This technique offers better results in articulations with less capacity for distension, such as the wrist, ankle, hand, and foot. This first part of two-part article reviews the current role of MRA in the upper limb. Special emphasis is placed on the shoulder joint, where its usefulness has been most clearly established. The usefulness of this technique in other joints is also described, reviewing the most important anatomic aspects, techniques and applications.

Comparison of the MR findings on indirect MR arthrography in patients with rotator cuff tears with and without symptoms

PURPOSE

To compare indirect magnetic resonance (MR) arthrography findings in patients with rotator cuff tears with and without symptoms.

MATERIALS AND METHODS

Indirect MR arthrography results of 15 asymptomatic and 23 symptomatic rotator cuff tears were retrospectively reviewed, comparing the type and size of tears and amount of subacrominal-subdeltoid bursal fluid.

RESULTS

There were 14 partial-thickness tears and one full-thickness tear in the asymptomatic group, with 4 small and 11 medium tears. In the symptomatic group, there were 16 partial-thickness and 7 full-thickness tears, with 14 small, 5 medium, and 4 large tears. In the asymptomatic group, the amount of subacrominal-subdeltoid bursal fluid was grade 0, 6 patients; grade 1, 6 patients; grade 2, 2 patients; and grade 3, 1 patient. In the symptomatic group, the amount of subacrominal-subdeltoid bursal fluid was grade 0, 4 patients; grade 1, 3 patients; grade 2, 8 patients; and grade 3, 8 patients. We found no statistically significant difference between symptomatic and asymptomatic tears in the kind and size of tears, and in the amount of subacrominal-subdeltoid bursal fluid.

CONCLUSION

We found no difference in the MR findings between symptomatic and asymptomatic rotator cuff tears.

Magnetic resonance arthrography

For decades, fluoroscopic arthrography was the only method available to image a joint with contrast enhancement. Advances in CT led to the natural development of CT arthrography. Development of MRI and its capability for multiplanar imaging led to direct magnetic resonance arthrography (MRA). This technique has been performed since 1987 and has surpassed CT arthrography in popularity in the United States. Indirect MRA developed subsequently to offer a less invasive alternative. This article presents an overview of direct MRA and addresses joint-specific issues regarding direct MRA. An overview of indirect MRA also is provided.

Use of intra-articular carbon dioxide and air for MR arthrography: a feasibility study

During animal experiments, carbon dioxide (CO(2)) and air were used as a novel contrast agent for direct magnetic resonance arthrography (MRAr). MRAr was performed after injection of CO(2) and air in the knee joints of two pigs. MR images of phantoms containing air, CO(2) and nitrogen were compared. After intra-articular injection, both present as a signal void on various sequences and permit sharp delineation of cartilage and other adjacent structures. Despite the potential for artefact generation, only a slight susceptibility artefact was seen after injection of CO(2) and air. In phantom experiments, air, CO(2) and nitrogen demonstrated identical slight regular susceptibility artefacts at the phantom margins. CO(2) MRAr can yield high contrast between cartilage, ligaments and synovium relative to the joint compartment. Therefore, this technique might be useful as an investigational method for the evaluation of cartilage surface lesions and possibly as an alternative contrast agent for clinical use.

Ankle MR Arthrography: How, Why, When

MR arthrography has become an important tool for the assessment of a variety of ankle disorders. MR arthrography may facilitate the evaluation of patients with suspected intra-articular pathology in whom conventional MR imaging is not sufficient for an adequate diagnosis and be useful for therapy planning. MR arthrography is valuable in the evaluation of ligamentous injuries, impingement syndromes, cartilage lesions, osteochondral lesions of the talus, loose bodies, and several synovial joint disorders. Indirect MR arthrography is a useful adjunct to conventional MR imaging and may be preferable to direct MR arthrography in cases in which an invasive procedure is contraindicated or when fluoroscopy is not available.

Reactive Carpal Synovitis: Initial Experience with MR Imaging

PURPOSE

To retrospectively evaluate the accuracy of various magnetic resonance (MR) imaging findings in the diagnosis of reactive carpal synovitis.

MATERIALS AND METHODS

Institutional review board approval was obtained, and the need for informed consent was waived. This study was compliant with the Health Insurance Portability and Accountability Act. Thirty-five consecutive patients (19 male and 16 female patients; age range, 13-57 years) who underwent arthroscopy and MR imaging within 4 weeks of surgery were evaluated by two reviewers for the following potential findings of synovitis: (a) distention of the pisotriquetral recess by fluid, (b) distention of the radial and/or prestyloid recess, (c) synovial enhancement (in patients who received contrast material), (d) amount of dorsal capsule distention, and (e) the location of bone marrow edema, if any. The chi2 and paired t tests were used to assess these findings in patients with and patients without arthroscopically proved synovitis. The sensitivity, specificity, positive and negative predictive values, and accuracy of these findings in the detection of synovitis were calculated.

RESULTS

Fluid in the pisotriquetral recess was seen in nine of the 14 patients with synovitis and five of the 21 patients without synovitis (P = .018). Distention of the radial and/or prestyloid recess was observed in six of the 14 patients with synovitis and two of the 21 patients without synovitis (P = .027). Among the 24 patients who received contrast material, synovial enhancement was seen in seven of eight patients with synovitis and three of 16 patients without synovitis (P = .002). The dorsal capsule measured 1-7 mm (mean, 3.07 mm) in the 14 patients with synovitis and 2-7 mm (mean, 3.76 mm) in the 21 patients without synovitis (P = .193). Although bone marrow edema was seen globally in similar frequencies (nine of 14 patients with synovitis, nine of 21 patients without synovitis), pisotriquetral bone marrow edema was seen only in patients with synovitis (two of nine patients).

CONCLUSION

Fluid in the pisotriquetral recess, enhancing synovium, and, less commonly, pisotriquetral bone marrow edema are MR imaging findings that may help in the diagnosis of reactive carpal synovitis.