Wrist MR Arthrography: How, Why, When

Ultrasound-guided injection and aspiration of small joints: techniques, pearls, and pitfalls

Ultrasound (US)-guided musculoskeletal intervention of small joints or joints other than the shoulder, elbow, hip, knee, and ankle can be technically challenging. Small joints produce a narrower landing zone for the needle and a smaller target that may be made even more inaccessible by bulky osteophytes. Sonographic (US) guidance offers important advantages including near-field visualization of the joint and soft tissues, ease of access, portability, ability to compare with the contralateral side, and lack of ionization radiation. This review article focuses on the performance of US-guided injections and aspirations involving small joints (joint capacity < 2 mL and/or typically evaluated or injected with a compact linear transducer). For each joint (temporomandibular, acromioclavicular, sternoclavicular, distal radioulnar, symphysis pubis, and joints of the digits of the hands and feet), a brief overview of the relevant anatomy, indications, procedural description, pearls and pitfalls will be highlighted. This article demonstrates the various approaches to diagnostic or therapeutic injection and aspiration of small joints with the aid of US images, cines and graphic illustrations, emphasizing joint positioning, anatomic landmarks, and needle trajectory for a safe and efficacious procedure. A brief review of available literature for each joint will also be provided.

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.

Radio-carpal wrist MR arthrography: comparison of ultrasound with fluoroscopy and palpation-guided injections

OBJECTIVE

To compare ultrasound- (US), fluoroscopy- (FL), and palpation-guided contrast injection techniques used for dorsal radio-carpal wrist MRA.

MATERIALS AND METHODS

Patients with chronic wrist pain were randomized as to which injection technique they underwent into three groups of 50 participants. Dorsal radio-carpal contrast injection was performed under US, FL guidance (one radiologist for each), or palpation guidance by an orthopedic surgeon. The three techniques were compared by procedure time, success rate, number of attempts needed, frequency and grade of extravasation, joint distension, and MRA image quality. Additionally, any change from baseline wrist pain was recorded using the visual analog scale (VAS) at five time points (immediately, 8 h, 24 h, 48 h, and 1 week) after injection.

RESULTS

One hundred and fifty patients (83 males and 67 females; mean age 29 ± 6.5 years) were included. Success rates for US- and FL-guided injections were 100%, while palpation-guided approach was significantly less successful (72%) (P = 0.02) with significantly more frequent extravasation (56%)(P < 0.001). US guidance was the least time-consuming (6.5 ± 1.6 min) compared to FL guidance (12.5 ± 1.9 min) and palpation guidance (8 ± 1.2 min) (all P < 0.001). The mean number of joint puncture attempts was significantly lower with imaging-guided techniques (1.1 ± 0.24 and 1.2 ± 0.4 for US and FL, P = 0.23) compared to palpation-guided one (1.6 ± 0.8) (P = 0.007). The largest increases in baseline-pain were 8-h post-injection, and US guidance was the least painful at all-time points (all P < 0.05). Joint distension and image quality were significantly better with imaging-guided techniques (P < 0.001 and P = 0.003).

CONCLUSIONS

US-guided radio-carpal injection is a less time-consuming, more tolerable, and successful radiation-free method when compared to FL guidance. Palpation-guided injections require multiple attempts to enter the joint with high failure rates and frequent extravasation.

SLAC and SNAC Wrist: The Top Five Things That General Radiologists Need to Know

Wrist osteoarthritis (OA) is a common painful condition that affects the patient’s quality of life by limiting the range of wrist motion and grip strength. Wrist OA often results from scapholunate advanced collapse (SLAC) or scaphoid nonunion advanced collapse (SNAC). Early diagnosis of SLAC and SNAC is crucial because it affects treatment planning. Thus, radiologists should be able to interpret the early imaging findings. This pictorial review discusses the pathophysiology and the clinical symptoms of SLAC and SNAC and presents the imaging findings with emphasis on the proper imaging algorithm. Finally, it focuses on the treatment according to the degenerative status of each of these patterns.

Carpal Instability: II. Imaging

Beyond clinical examination, the various forms of carpal instability are assessed with radiologic methods and arthroscopy. For this purpose, the imaging demand for spatial and contrast resolution is particularly high because of the small ligamentous structures involved. The entities of carpal instability are classified into degrees of severity. Early (dynamic) forms of instability can either be indirectly detected with X-ray stress views and cineradiography or by direct visualization of ruptured ligaments in high-resolution magnetic resonance (MR) imaging and MR or computed tomography (CT) arthrography, with the latter the standard of reference in imaging. Advanced (static) forms of carpal instability are sufficiently well detected on radiographs; visualization of early carpal osteoarthritis is superior on CT. To prevent disability of the hand, the radiologist has to provide an early and precise diagnosis. This case-based review highlights the imaging procedures suitable for detection and classification of carpal instability.

MRI of the Wrist Ligaments

Technological advances in magnetic resonance imaging (MRI) have improved radiologists' ability to evaluate wrist ligaments. MRI interpretation often guides clinical management. This article aims to review the normal and pathologic appearance of intrinsic and extrinsic wrist ligaments with a focus on MRI. Variant anatomy, imaging pearls, and clinical significance are also discussed. Special attention is paid to key wrist ligaments that play a role in carpal stability.

Traumatic injury of the triangular fibrocartilage complex (TFCC)-a refinement to the Palmer classification by using high-resolution 3-T MRI

OBJECTIVE

The aim of this study was to investigate the MR features of the traumatic injury of the triangular fibrocartilage complex (TFCC) by using high-resolution 3-T magnetic resonance imaging (MRI) and to refine the Palmer classification system.

MATERIALS AND METHODS

From November 2015 to May 2019, sixty-seven patients met the including and excluding criteria and were enrolled into this retrospective study. All subjects had high-resolution 3-T MRI scan of the wrist and eleven had indirect MR arthrography of the wrist. All the MRI were read by two experienced musculoskeletal radiologists. Diagnostic sensitivity, specificity, and accuracy of MRI were calculated by using the arthroscopy and surgery as the standard of reference. A P value less than 0.05 was considered statistically significant. The interobserver agreement was assessed by kappa analysis.

RESULTS

There were 49 cases of TFCC injuries proven by the arthroscopy or surgery. The TFCC injuries in the other 18 patients were proved by the combination of clinical follow-up examination and follow-up MRI. Among the arthroscopy- or surgery-confirmed cases, there were 32 patients with original Palmer injuries (IA = 10, IB = 19, ID = 3), 5 with capsular detachment, 4 with bucket-handle tear of the TFCC that have rarely been reported, and 8 with complex injuries that involved the listed classifications above. The sensitivities and specificities of MRI for diagnosing IA, IB, ID, complex injuries, and bucket-handle tear were 67-100% and 90-100%, and overall good to perfect interobserver agreements (kappa, 0.64-1.00). The diagnostic performance for the capsular detachment was lower (kappa, 0.38).

CONCLUSION

With high-resolution 3-T MRI, more detailed injury patterns were found including capsular injuries, the horizontal tear of the articular disk, and the bucket-handle tear. It is necessary to refine the classic Palmer classification of TFCC injuries.

MR arthrography versus conventional MRI and diagnostic arthroscope in patients with chronic wrist pain

Objective

To assess the diagnostic accuracy of direct wrist MR arthrography (MRA) compared to conventional MRI in diagnosis of different pathologic entities causing chronic wrist pain.

Materials and methods

37 consecutive patients 22 males and 15 females, with age range from 16 to 49 years "mean age 28 years" complaining of unexplained chronic wrist pain were prospectively examined by using MRI and MRA with arthroscopic correlation in 25 of them. Findings were divided into 5 main groups of lesions including triangular fibrocartilage complex (TFCC) lesions, ligamentous injuries, osseous lesions, tendon pathology and ganglion.

Results

MRA picked up more ligamentous injuries and triangular fibrocartilage complex (TFCC) lesions that couldn`t be detected on MRI study while both were equal in detection of other types of lesions. TFCC lesions were the most common pathologic findings in both MRI and MRA. Arthroscopic correlation in 25 suspected TFCC lesions (clinically, radiologically or both) revealed that the sensitivity / specificity / accuracy of MRI and MRA were 87.5% / 100% / 96% and 100% / 100% / 100% respectively for central lesions while were 71.4% / 81.3% / 76% and 100% / 90.9% / 96% respectively For peripheral lesions. Extra-capsular lesions, like tenosynovitis and fracture hook of hamate couldn`t be confirmed arthroscopically.

Conclusion

MRA can replace both MRI and diagnostic arthroscopy in detecting causes of chronic wrist pain.

Comparison of Magnetic Resonance Arthrography and Wrist Arthroscopy in the Evaluation of Chronic Wrist Pain in Indian Population

BACKGROUND

The purpose of our study was to compare magnetic resonance arthrography (MRA) as a diagnostic modality against the gold standard of wrist arthroscopy in the evaluation of chronic wrist pain.

MATERIALS AND METHODS

Thirty three patients with chronic wrist pain suspected to have ligament injuries of the wrist were prospectively recruited. They underwent MRA examinations followed by wrist arthroscopy. Arthroscopic findings were compared with radiological findings focusing on three important structures - triangular fibrocartilage complex (TFCC), scapholunate ligament (SLL), and lunotriquetral ligament (LTL).

RESULTS

For the 17 patients with TFCC tears/perforations on arthroscopy, MRA gave a sensitivity (SEN) = 88%, specificity (SPE) = 87.5%, positive predictive value (PPV) = 88%, and negative predictive value (NPV) = 87.5%. For the 13 patients with SLL tears on arthroscopy, MRA gave SEN = 77%, SPE = 100%, PPV = 100%, and NPV = 87%. For the 7 patients with LTL tears on arthroscopy, MRA gave SEN = 29%, SPE = 100%, PPV = 100%, and NPV = 84%. A composite correlation between findings on MRA and wrist arthroscopy revealed an overall SEN = 73%, SPE = 96%, PPV = 93%, and NPV = 85% for MRA, with overall accuracy = 88%.

CONCLUSIONS

The presented diagnostic results of MRA are superior to those of magnetic resonance imaging quoted in literature. MRA is a potent tool for evaluating chronic wrist pain but tends to miss lesions of intrinsic carpal ligaments (SLL and LTL) more than TFCC. Wrist arthroscopy may be recommended when the clinical suspicion is strong.

Secondary Abutment Syndromes of the Wrist in Trauma: A Pictorial Essay

Traumatic lesions of the wrist occur frequently and may give rise to underdiagnosed secondary abutment syndromes. The latter are a common cause of incapacitating pain and limited range of motion, despite minimal or even absent alterations on radiographs. Moreover, the complex wrist anatomy often results in ignorance or underappreciation of these syndromes.

This paper presents a pictorial review of frequent and rare secondary abutment syndromes at the wrist joint, which – in contrast to primary abutment syndromes – are not based on anatomical variants or congenital deformations. The merit of each imaging modality is briefly mentioned.

Anatomy and injuries of the pediatric wrist: beyond the basics

Ligamentous injuries of the pediatric wrist, once thought to be relatively uncommon, are increasingly recognized in the context of acute high-energy mechanism trauma and chronic axial loading, including those encountered in both recreational and high-performance competitive sports. Recent advances in MR-based techniques for imaging the pediatric wrist allow for sensitive identification of these often radiographically occult injuries. Detailed knowledge of the intrinsic and supportive extrinsic ligamentous complexes, as well as normal developmental anatomy and congenital variation, are essential to accurately diagnose injuries to these structures. Early identification of ligamentous injury of the pediatric wrist is essential within the conservative treatment culture of modern pediatric orthopedics because treatment of these lesions often necessitates surgery, and outcomes often depend on early and sometimes aggressive intervention. In this article, we review MR arthrogram technique and pediatric wrist anatomy, and correlate appearances on MR and selected ligamentous pathologies of the pediatric wrist.

Point-of-care wrist ultrasonography in trauma patients with ulnar-sided pain and instability

OBJECTIVE

We evaluated the effectiveness of point-of-care wrist ultrasonography compared with 3T-magnetic resonance imaging (MRI) for diagnosing triangular fibrocartilage complex (TFCC) injuries in trauma patients with ulnar-sided pain and instability. Moreover, we assessed the inter-observer variability between an emergency physician and a musculoskeletal radiology fellow.

MATERIAL AND METHODS

A prospective cross-sectional study was conducted in an emergency department; patients with ulnar-sided sprain and instability were recruited. An emergency physician and a musculoskeletal radiology fellow independently evaluated the TFC, meniscal homologue, volar and dorsal distal radioulnar ligaments, and extensor carpi ulnaris using point-of-care ultrasonography. Findings were classified as normal, partial rupture, or complete rupture. Wrist 3T-MRI was used as the reference standard. We compared the diagnostic values for point-of-care ultrasonography obtained by both reviewers using DeLong's test. Intra-class correlation coefficients (ICCs) were calculated for agreement between each reviewer and the reference standard, and directly between the two reviewers.

RESULTS

Sixty-five patients were enrolled. Point-of-care wrist ultrasonography showed acceptable sensitivity (97.2-99.1%), specificity (96.8-97.3%), and accuracy (96.9-97.9%); these diagnostic performance values did not differ significantly between reviewers (p=0.58-0.98). Agreement between each reviewer and the reference standard was excellent (emergency physician, ICC=0.964; musculoskeletal radiology fellow, ICC=0.976), as was the inter-observer agreement (ICC=0.968).

CONCLUSION

Point-of-care wrist ultrasonography is as precise as MRI for detecting TFCC injuries, and can be used for immediate diagnosis and further preoperative imaging. Moreover, it may shorten the interval from emergency department admission to surgical intervention while reducing costs.

High-resolution 3-T MRI of the triangular fibrocartilage complex in the wrist: injury pattern and MR features

OBJECTIVES

To investigate if using high-resolution 3-T MRI can identify additional injuries of the triangular fibrocartilage complex (TFCC) beyond the Palmer classification.

MATERIALS AND METHODS

Eighty-six patients with surgically proven TFCC injury were included in this study. All patients underwent high-resolution 3-T MRI of the injured wrist. The MR imaging features of TFCC were analyzed according to the Palmer classification.

RESULTS

According to the Palmer classification, 69 patients could be classified as having Palmer injuries (52 had traumatic tears and 17 had degenerative tears). There were 17 patients whose injuries could not be classified according to the Palmer classification: 13 had volar or dorsal capsular TFC detachment and 4 had a horizontal tear of the articular disk.

CONCLUSION

Using high-resolution 3-T MRI, we have not only found all the TFCC injuries described in the Palmer classification, additional injury types were found in this study, including horizontal tear of the TFC and capsular TFC detachment. We propose the modified Palmer classification and add the injury types that were not included in the original Palmer classification.

[Ligament injuries of the wrist]

The distal radioulnar joint, the triangular fibrocartilage complex (TFCC) and the wrist are stabilized by many ligaments allowing not only a wide range of motion but also providing sufficient stability. The complex arrangement of carpal ligaments and prosupination around the forearm joint enables multiaxial motion patterns. In the wrist, intra-articular ligaments can be differentiated from extra-articular capsular ligaments as well as intrinsic and extrinsic ligament courses. Imaging is essential for classification of dynamic and static instability patterns. This review article illustrates the ligamentous anatomy of the wrist, the symptoms of carpal instability as well as the diagnostic capability of projection radiography, cinematography, computed tomography (CT) arthrography, magnetic resonance imaging (MRI) and MR arthrography.

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy

BACKGROUND

The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese.

METHODS

Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists.

RESULTS

Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr.

CONCLUSION

High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese.

Imaging of Sports-related Hand and Wrist Injuries: Sports Imaging Series

Hand and wrist injuries are common occurrences in amateur and professional sports and many of them are sport-specific. These can be divided into two categories: traumatic injuries and overuse injuries. The aim of this article is to review the most common hand and wrist sports-related lesions. Acute wrist injuries are predominantly bone fractures, such as those of the scaphoid, hamate hook, and ulnar styloid. Ligament lesions are more challenging for radiologists and may lead to carpal instability if undiagnosed. Overuse wrist injuries are mainly represented by tendinous disorders, with De Quervain syndrome and extensor carpi ulnaris tendon disorders being the most common among them; however, there are other possible disorders such as impaction syndromes, stress fractures, and neurovascular lesions. Finally, finger lesions, including closed-tendon injuries (mallet and boutonniere injuries, jersey finger, and boxer's knuckle), flexor pulley injuries, and skier's thumb, should also be detected. (©) RSNA, 2016 Online supplemental material is available for this article.

Imaging in carpal instability

Carpal instability is a complex and heterogeneous clinical condition. Management requires accurate identification of structural injury with an understanding of the resultant movement (kinematic) and load transfer (kinetic) failure. Static imaging techniques, such as plain film radiography, stress views, ultrasound, magnetic resonance, MR arthrography and computerized tomography arthrography, may accurately depict major wrist ligamentous injury. Dynamic ultrasound and videofluoroscopy may demonstrate dynamic instability and kinematic dysfunction. There is a growing evidence base for the diagnostic accuracy of these techniques in detecting intrinsic ligament tears, but there are limitations. Evidence of their efficacy and relevance in detection of non-dissociative carpal instability and extrinsic ligament tears is weak. Further research into the accuracy of existing imaging modalities is still required. Novel techniques, including four-dimensional computerized tomography and magnetic resonance, can evaluate both cross-sectional and functional carpal anatomy. This is a narrative review of level-III studies evaluating the role of imaging in carpal instability.

Comparison of conventional MRI and MR arthrography in the evaluation wrist ligament tears: A preliminary experience

Aims:

To compare conventional magnetic resonance imaging (MRI) and direct magnetic resonance (MR) arthrography in the evaluation of triangular fibrocartilage complex (TFCC) and intrinsic wrist ligament tears.

Materials and Methods:

T1-weighted, fat suppressed (FS) proton density plus T2-weighted (FS PD/T2), 3D multiple-echo data image combination (MEDIC) sequences and direct MR arthrography were performed in 53 patients with wrist pain. Images were evaluated for the presence and location of TFCC, scapholunate ligament (SLL) and lunatotriquetral ligament (LTL) tears, and imaging findings were compared with operative findings in 16 patients who underwent arthroscopy or open surgery (gold standard).

Results:

Sixteen patients underwent arthroscopy/open surgery: 12 TFCC tears were detected arthroscopically out of which 9 were detected on FS PD/T2 sequence, 10 on MEDIC sequence, and all 12 were detected on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in the detection of TFCC tears were 75%, 83.3%, and 100%, respectively. Out of the eight arthroscopically confirmed SLL tears, three tears were detected on FS PD/T2 sequence, five on MEDIC sequence, and all eight were visualized on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in detecting SLL tears were 37.5%, 62.5%, and 100%, respectively. One arthroscopically confirmed LTL tear was diagnosed on FS PD/T2 sequence, three on MEDIC sequence, and all five arthroscopically confirmed LTL tears were detected with MR arthrography. The sensitivities of PD, MEDIC sequences, and MR arthrography in detecting LTL tears were 20%, 40%, and 100%, respectively.

Conclusions:

MR arthrography is the most sensitive and specific imaging modality for the evaluation of wrist ligament tears.

Real-time magnetic resonance imaging (MRI) during active wrist motion--initial observations

BACKGROUND

Non-invasive imaging techniques such as magnetic resonance imaging (MRI) provide the ability to evaluate the complex anatomy of bone and soft tissues of the wrist without the use of ionizing radiation. Dynamic instability of wrist--occurring during joint motion--is a complex condition that has assumed increased importance in musculoskeletal medicine. The objective of this study was to develop an MRI protocol for evaluating the wrist during continuous active motion, to show that dynamic imaging of the wrist is realizable, and to demonstrate that the resulting anatomical images enable the measurement of metrics commonly evaluated for dynamic wrist instability.

METHODS

A 3-Tesla "active-MRI" protocol was developed using a bSSFP sequence with 475 ms temporal resolution for continuous imaging of the moving wrist. Fifteen wrists of 10 asymptomatic volunteers were scanned during active supination/pronation, radial/ulnar deviation, "clenched-fist", and volarflexion/dorsiflexion maneuvers. Two physicians evaluated distal radioulnar joint (DRUJ) congruity, extensor carpi ulnaris (ECU) tendon translation, the scapholunate (SL) interval, and the SL, radiolunate (RL) and capitolunate (CL) angles from the resulting images.

RESULTS

The mean DRUJ subluxation ratio was 0.04 in supination, 0.10 in neutral, and 0.14 in pronation. The ECU tendon was subluxated or translated out of its groove in 3 wrists in pronation, 9 wrists in neutral, and 11 wrists in supination. The mean SL interval was 1.43 mm for neutral, ulnar deviation, radial deviation positions, and increased to 1.64 mm during the clenched-fist maneuver. Measurement of SL, RL and CL angles in neutral and dorsiflexion was also accomplished.

CONCLUSION

This study demonstrates the initial performance of active-MRI, which may be useful in the investigation of dynamic wrist instability in vivo.

Musculoskeletal aspiration procedures

With advances in imaging technology, there has been a significant increase in the number and range of interventional musculoskeletal image-guided procedures. One of the most commonly performed image-guided musculoskeletal interventions is the diagnostic and therapeutic percutaneous aspiration and drainage of multiple types of intra-articular, juxta-articular, and intramuscular pathologic fluid collections. These procedures may be performed under fluoroscopic, ultrasound, computed tomography, or even magnetic resonance guidance depending on the location to be accessed, type of pathology, patient characteristics, and operator preference. Musculoskeletal image-guided aspiration and drainage procedures are minimally invasive and generally very safe while offering valuable diagnostic information as well as therapeutic benefit. This article focuses on the appropriate indications, contraindications, and general technique for accessing the major joints via imaging guidance. For each joint, we discuss pertinent anatomy, appropriate imaging modalities, and preferred approaches to gaining intra-articular access. Additionally, the article discusses some of the more frequently encountered juxta-articular and intramuscular fluid collections that can be accessed and aspirated via percutaneous intervention, with mention of the importance of recognizing extremity sarcomas that can mimic these benign collections.

Wrist MRI Arthrogram v Wrist Arthroscopy: What are we Finding?

The aim of the study was to compare the radiological findings of wrist arthrogram with wrist arthroscopy. This allowed us to establish the accuracy (sensitivity, specificity) of MRI arthrogram as a diagnostic tool. Thirty patients (20 female and 10 male) have undergone both wrist MRI arthrogram and wrist arthroscopy over the last 3 years at a District General Hospital. The mean age at arthrogram was 42.4 years with an average 6.7 month interval between the two procedures.

The MRI arthrogram was reported by a consultant radiologist with an interest in musculoskeletal imaging and the arthroscopies performed by two upper limb surgeons. Patients who underwent both procedures were identified. The arthrogram reports and operation notes were examined for correlation. Three main areas of pathology were consistently examined: TFCC (triangular fibrocartilage complex), scapholunate and lunotriquetral ligament tears. The sensitivity and specificity of arthrogram was calculated for each. Other areas of pathology were also noted.

In the case of TFCC tears MRI arthrogram had 90% sensitivity and 75% specificity. The lunotriquetral ligament examination with this technique was 100% sensitivity and specificity. However for scapholunate ligament tears it only had 91% sensitivity and 88% specificity.

Wrist arthrogram and arthroscopy are both invasive techniques. In cost terms the arthrogram remains cheaper but is superseded by arthroscopy as it is both diagnostic and therapeutic.

Sonographically guided distal radioulnar joint injection: technique and validation in a cadaveric model

Distal radioulnar joint (DRUJ) disorders are uncommon but important causes of ulnar-sided wrist pain and disability. Fluoroscopically guided injections may be performed to diagnose or treat DRUJ-related pain or as part of a diagnostic arthrogram. Sonographic guidance may provide a favorable alternative to fluoroscopic guidance for distal DRUJ injections. This report describes and validates a sonographically guided technique for DRUJ injections in an unembalmed cadaveric model. An experienced clinician used sonographic guidance to inject diluted colored latex into the DRUJs of 10 unembalmed cadaveric specimens. Subsequent dissection by a fellowship-trained hand surgeon confirmed accurate injections in all 10 specimens. Two cases of ulnocarpal flow, indicative of triangular fibrocartilage injury, were noted during injection and subsequently confirmed during dissection. Clinicians should consider using sonographic guidance to perform DRUJ injections when clinically indicated. Further research should explore the efficacy of sonographically guided DRUJ injections to treat patients with painful DRUJ syndromes or to evaluate the triangular fibrocartilage complex in patients with ulnar wrist pain syndromes.

Glenohumeral joint instability

Due to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician.

Differences between radial and ulnar deviation of the wrist in the study of the intrinsic intercarpal ligaments: magnetic resonance imaging and gross anatomic inspection in cadavers

OBJECTIVE

To demonstrate how radial and ulnar deviation of the wrist can affect the visualization of the intrinsic intercarpal ligaments using magnetic resonance (MR) imaging, MR arthrography and gross anatomic inspection in cadavers.

MATERIALS AND METHODS

The detectability of the intrinsic intercarpal ligaments of ten fresh human wrists was analyzed in coronal, axial and sagittal images in the neutral position and in radial and ulnar deviation with MR imaging and MR arthrography. The findings were then correlated with gross anatomic inspection. Additionally, quantitative measurements including the radiocarpal distances and capitate angles were performed.

RESULTS

Differences were noted in the visual conspicuity of only the intercarpal ligaments of the proximal carpal row with different techniques and wrist positions. The average width of the radiocarpal joint was 0.62 mm, 1.55 mm and 2.0 mm (radial side) and 3.78 mm, 2.25 mm and 1.16 mm (ulnar side) in radial deviation, neutral position, and ulnar deviation of the wrist, respectively. Statistically, these maneuvers produced significant opening in the ulnar side during radial deviation (Student's t-test; P = 0.0005) and in the radial side in ulnar deviation (P = 0.007).

CONCLUSION

Significant differences in the width of the radiocarpal joint were observed during radial and ulnar deviation of the wrist, influencing the visualization of the intrinsic ligaments, mainly the scapholunate and lunotriquetral ligaments. The use of MR arthrography with radial and/or ulnar deviation has the potential to improve diagnosis in clinical cases in which injury to one or both of these ligaments is suggested.

Ulnar-sided wrist pain. II. Clinical imaging and treatment

Pain at the ulnar aspect of the wrist is a diagnostic challenge for hand surgeons and radiologists due to the small and complex anatomical structures involved. In this article, imaging modalities including radiography, arthrography, ultrasound (US), computed tomography (CT), CT arthrography, magnetic resonance (MR) imaging, and MR arthrography are compared with regard to differential diagnosis. Clinical imaging findings are reviewed for a more comprehensive understanding of this disorder. Treatments for the common diseases that cause the ulnar-sided wrist pain including extensor carpi ulnaris (ECU) tendonitis, flexor carpi ulnaris (FCU) tendonitis, pisotriquetral arthritis, triangular fibrocartilage complex (TFCC) lesions, ulnar impaction, lunotriquetral (LT) instability, and distal radioulnar joint (DRUJ) instability are reviewed.

Magnetic resonance arthrography

Magnetic resonance arthrography is widely used throughout the world for joint imaging. It extends the capabilities of conventional MR imaging because contrast solution distends the joint capsule, outlines intraarticular structures, and extends into soft tissue tears and defects. MR arthrography exploits the natural advantages gained from a joint effusion and can be performed on any joint.

MR arthrography of the wrist: controversies and concepts

Magnetic resonance arthrography (MRA) has become the preferred modality for imaging patients with internal derangement of the wrist. However, several aspects of MRA use need to be clarified before a standardized approach to the imaging of internal derangement of the wrist can be developed. The objective of the study is to evaluate the efficiency of different magnetic resonance (MR) sequences in the detection of lesions of the triangular fibrocartilage complex (TFCC) and scapholunate and lunotriquetral ligaments on direct MRA. Thirty-one consecutive direct magnetic resonance arthrographic examinations of the wrist using a wrist surface coil were performed for the assessment of the TFCC and intrinsic ligaments on a 1.5-T MR imaging system (Signa; 16 channel, Excite, GE Healthcare, Milwaukee, WI, USA). All patients had wrist pain, and in six cases, there was associated clinical carpal instability. The presence, location, and extent of TFCC, scapholunate ligament (SLL), and lunotriquetral ligament (LTL) lesions on T1 fat-saturated, multiplanar gradient recalled (MPGR) and short tau inversion recovery (STIR) images were identified, compared, and analyzed. Forty-one lesions of the TFCC, SLL, and LTL were visualized on contrast-sensitive (T1 fat-saturated) images in 23/31 (74.2%) patients. Twenty-one lesions of the TFCC and intrinsic ligaments were visualized on noncontrast-sensitive (MPGR and STIR) images (15 tears of the TFCC and six tears of the SLL and LTL). All of these lesions were seen on T1 fat-saturated images; 48.8% (20/41) lesions seen on T1 fat-saturated images (eight tears of TFCC and 12 tears of SLL and LTT) were not seen on MPGR and/or STIR images. Superior contrast resolution, joint distention, and the flow of contrast facilitate the diagnosis of lesions of the TFCC and intrinsic ligaments on contrast-sensitive sequences making MRA the preferred modality for imaging internal derangements of the wrist. Little agreement exists regarding the value and location of perforations of the intrinsic ligaments given that both traumatic and degenerative perforations may be symptomatic. Noncommunicating defects of the ulnar attachments of the triangular fibrocartilage (TFC), tears of the dorsal segment of the SLL, and defects at the lunate attachment of the SLL have a higher likelihood of being symptomatic and caused by trauma rather than by degenerative perforation. Although no consensus exists, it would appear that most arthrographies should be started with a radiocarpal injection. Injection into the distal radioulnar joint should be added if no communicational defects are visualized following radiocarpal injection in patients with ulnar-sided wrist pain.

Management of wrist injuries

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the anatomy and the biomechanical properties of the wrist. 2. Understand the standard examination process for wrist injuries. 3. Accurately diagnose common wrist conditions. 4. Establish a management plan for wrist problems.

BACKGROUND

Although common, wrist injuries and conditions are difficult to treat if the physician is unfamiliar with their management.

METHODS

Wrist anatomy and kinematics are discussed. Physical and radiographic examinations that are mandatory for diagnosing wrist conditions are presented. Common wrist injuries are reviewed.

RESULTS

Understanding the anatomy and kinematics of the wrist is important in diagnosing and treating wrist conditions and in predicting outcomes after treatment. Physical examination of the wrist requires an understanding of the surface anatomy and a number of specific maneuvers. Physicians should also be familiar with other diagnostic tests, which include radiography, arthrography, computed tomography, magnetic resonance imaging, and arthroscopy.

CONCLUSIONS

Physicians who treat wrist injuries should be able to establish an adequate management plan for common wrist injuries and conditions and be able to predict outcomes based on these treatment plans.

Imaging of Ulnar-Sided Wrist Pain

Ulnar-sided wrist pain has long been a diagnostic problem, partly because of the complex anatomy and many possible causes of pain in this region. This article discusses anatomy, pathophysiology, and imaging appearance of the more common causes, including tears of the triangular fibrocartilage complex, disorders of the distal radioulnar joint, tears of the lunotriquetral ligament, disorders of the extensor carpi ulnaris tendon, disorders of the pisotriquetral joint, the impingement and impaction syndromes, and ulnar wrist masses. Along with clinical history and physical examination, imaging is important in evaluation of ulnar-sided wrist pain. Conventional radiographs, conventional arthrography, CT, MRI, and MR arthrography are useful modalities that are often used in concert to help guide diagnosis and treatment.

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.

Carpal instability

This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads ("dyskinetics") or suffers from abnormal motion of its bones during movement ("dyskinematics"). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being "occult" for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the hand surgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis.