Magnetic resonance arthrography of the hip: technique and spectrum of findings in younger patients

Magnetic Resonance Imaging and Magnetic Resonance Arthrography Are Both Reliable and Similar When Measuring Hip Capsule Thickness in Patients With Femoroacetabular Impingement Syndrome

Purpose

To propose an accurate method of measuring hip capsular thickness in patients with femoroacetabular impingement syndrome and to compare the reliability of these measurements between magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA).

Methods

A previously established database of patients with femoroacetabular impingement syndrome (FAIS) was used to identify candidates with preoperative MRI or MRA from November 2018 to June 2021. Two reviewers independently examined preoperative imaging for 85 patients. Capsular thickness was measured in 12 standardized locations. Intraclass correlation coefficients (ICCs) were calculated using an absolute-agreement, 2-way random-effects model. Using the same method, 30 patients were randomly selected for repeat measurements by 1 reviewer following a washout period. Ten additional patients with preoperative MRI and MRA of the same hip were identified to compare measurements between modalities using paired samples t test.

Results

ICCs for measurements on MRIs and MRAs using these proposed measurements to compare inter-rater reliability were 0.981 and 0.985. ICCs calculated using measurements by a single reviewer following a washout period for intrarater reliability were 0.998 and 0.991. When comparing MRI and MRA measurements in the same patient, t test for all pooled measurements found no difference between modality (P = .283), and breakdown of measurements by quadrant found no difference in measurements (P > .05), with the exception of the inferior aspect of the capsule on coronal sequences (P = .023).

Conclusions

In patients with FAIS, both MRI and MRA have excellent reliability for quantifying hip capsular thickness. A difference in capsular thickness was found only when comparing MRI and MRA on inferior coronal aspects of the hip capsule, indicating interchangeability of these imaging modalities when measuring the clinically important aspects of the hip capsule.

Level of Evidence

Level IV, diagnostic case series.

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.

Image quality of hip MR arthrography with intra-articular injection of hyaluronic acid versus gadolinium-based contrast agent in patients with femoroacetabular impingement

OBJECTIVE

To compare image quality of magnetic resonance arthrography (MRA) of the hip with intra-articular injection of high-viscosity hyaluronic acid (HA-MRA) versus Gd-based contrast agent (Gd-MRA) in patients with femoroacetabular impingement (FAI).

MATERIALS AND METHODS

Design: single-centre, observational, retrospective, inter-individual, and cross-sectional. FAI patients who underwent HA-MRA (3 mL of high-viscosity HA plus 17 mL of saline) were compared with 37 age- and sex-matched FAI patients who underwent Gd-MRA (20 mL of 2 mmol/L solution of gadopentetate dimeglumine). Two independent blinded radiologists assessed image quality for all sequences (two-dimensional proton density, non-fat-sat axial, fat-sat coronal and sagittal; three-dimensional dual-echo steady state), using a 5-point Likert scale considering separately labrum, cartilage, round ligament, transverse ligament, and capsule. Pearson χ² and Cohen κ were used.

RESULTS

The HA-MRA group was composed of 37 patients (23 males, 14 females; median age 38 years), the Gd-MRA group of 37 patients (21 males, 16 females; median age 38 years), without significant difference for age (p = 0.937) and sex (p = 0.636). Image quality did not differ between the two readers for any structure: labrum (p ≥ 0.340), cartilage (p ≥ 0.198), round ligament (p ≥ 0.255), transverse ligament (p ≥ 0.806), and capsule (p ≥ 0.314). Inter-reader agreement (κ) ranged from 0.785 to 1.000.

CONCLUSIONS

HA-MRA provided an image quality not significantly different from that of Gd-MRA. This may open the possibility of combining MRA and viscosupplementation in one single procedure.

Magnetic Resonance Imaging in Symptomatic Children With Hereditary Multiple Exostoses of the Hip

BACKGROUND

Magnetic resonance imaging (MRI) is useful in evaluating nontraumatic hip pain. It provides information about associated injuries like labral/chondral tears or ischiofemoral impingement (IFI). However, in hereditary multiple exostoses (HME) there has been no report about MRI findings in symptomatic children with hip involvement.

METHODS

Records of children with HME and hip osteochondromas, who had hip MRI/magnetic resonance arthrography, were reviewed. The presence of chondral lesions and labral tears, as well the presence of IFI, was recorded. IFI was defined as edema or fatty replacement/atrophy in the quadratus femoris muscle or decrease of the space for this muscle between the ischium and the proximal femur. The measurements used to determine the space included the ischiofemoral space, the quadratus femoris space, and the minimum ischiofemoral space (MIFS). All measurements were performed on axial T1-weighted images.

RESULTS

Ten children were included (4 males, 6 females). In 2 patients, MRI was unilateral, therefore a total of 18 hips were analyzed. The indication for MRI was hip pain. Mean age, when MRI was performed, was 11.7 years. Labral tears were found in 44% (8/18) and chondral lesions in 33% (6/18) of the hips. The mean ischiofemoral space was 17.2 mm (SD, 7.3), the mean quadratus femoris space was 14.9 mm (SD, 5.3), and the mean MIFS was of 12.8 mm (SD, 5.9). IFI was seen in 44% (8/18) of hips. Two patients had bilateral IFI. MIFS was <10 mm in all hips with IFI (8/8). Of these hips, 88% (7/8) had edema of the quadratus femoris muscle and 38% (3/8) had fatty replacement/atrophy in the muscle. Osteochondromas were seen in the lesser trochanter in all hips with IFI (8/8) and in the ischium in 50% of them (4/8).

CONCLUSIONS

In symptomatic children with HME of the hip, MRI is helpful in detecting the source of pain. A high percentage of these children have IFI and intra-articular lesions. These findings can play an important role in the indication and planning of the surgical approach.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

Sports Injuries about the Hip: What the Radiologist Should Know

Injuries of the hip and surrounding structures represent a complex and commonly encountered scenario in athletes, with improper diagnosis serving as a cause of delayed return to play or progression to a more serious injury. As such, radiologists play an essential role in guiding management of athletic injuries. Familiarity with hip anatomy and the advantages and limitations of various imaging modalities is of paramount importance for accurate and timely diagnosis. Magnetic resonance (MR) imaging is often the modality of choice for evaluating many of the injuries discussed, although preliminary evaluation with conventional radiography and use of other imaging modalities such as ultrasonography (US), computed tomography, and bone scintigraphy may be supplementary or preferred in certain situations. Stress fractures, thigh splints, and posterior hip dislocations are important structural injuries to consider in the athlete, initially imaged with radiographs and often best diagnosed with MR imaging. Apophyseal injuries are particularly important to consider in young athletes and may be acute or related to chronic repetitive microtrauma. Femoroacetabular impingement has been implicated in development of labral tears and cartilage abnormalities. Tear of the ligamentum teres is now recognized as a potential cause of hip pain and instability, best evaluated with MR arthrography. Greater trochanteric pain syndrome encompasses a group of conditions leading to lateral hip pain, with US playing an increasingly important role for both evaluation and image-guided treatment. Muscle injuries and athletic pubalgia are common in athletes. Lastly, snapping hip syndrome and Morel-Lavallée lesions are two less common but nonetheless important considerations. ^©RSNA, 2016.

Clinical and surgical correlation of hip MR arthrographic findings in adolescents

OBJECTIVE

The purpose of this study was to analyze the utility of MRA-H in adolescents by comparing the results of imaging with surgical findings and/or clinical outcome.

MATERIAL AND METHODS

After obtaining appropriate IRB approval, the Radiologic Information System database was queried for all patients 13-18 years of age who underwent MRA-H from 2004 through 2013. The electronic medical record was reviewed for clinical history, clinical examination findings, and operative notes. MRA-H images were reviewed for soft tissue abnormalities (labral tear, paralabral ganglion, articular cartilage loss, synovitis, ligament tears) and bony abnormalities (cam-type femoroacetabular impingement (FAI), pincer-type FAI, hip dysplasia). MRA-H findings were correlated with surgical findings and with clinical outcomes.

RESULTS

Twenty-six patients with labral tears by MRA-H were included in study and grouped as follows: Group I) patients who underwent surgical management (n=10); group II) patients managed non-surgically (medication, intra-articular injection, physical therapy) (n=9); group III) patients lost to follow up after being advised to have surgery (n=7). With regard to presenting symptomatology, 87.5% of patients with labral tear had groin pain. Of those patients who were diagnosed with a labral tear, 52% were categorized as idiopathic labral tears, 26% as secondary tears (secondary to abnormal bony morphology), and 22% as traumatic labral tears. The labral tears were found to be anterior in 61% and posterior in 22%. Associated articular cartilage lesions were found in 29% of patients. In group I (surgical patients), MRA-H labral findings were confirmed at surgery in 9/10. Seventy percent of labral tears in our study had some form of abnormal bony morphology. Nine of the 12 patients with bone abnormalities were derived from group I patients. Six out of 7 patients with cam-type FAI had a labral tear.

CONCLUSION

Labral tears diagnosed by MRA-H in the adolescent population correlated well with clinical examination and surgical findings. Also, MRA-H contributed by defining bony morphology that was directly applied to surgical management. Non-surgical management of labral tears diagnosed on MRA-H had a generally favorable outcome.

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.