MR arthrography of the hip: diagnostic performance of a dedicated water-excitation 3D double-echo steady-state sequence to detect cartilage lesions

Radial Planes in Hip Magnetic Resonance Imaging: Techniques, Applications, and Perspectives

The hip cartilage and labrum, as the main targets of femoroacetabular impingement, sports-related or traumatic damage, as well as congenital and developmental abnormalities, have attracted increasing attention with the development of magnetic resonance imaging (MRI) and hip arthroscopy. MRI is a commonly used imaging modality to noninvasively visualize the hip cartilage and labral lesions. However, conventional orthogonal MRI planes encounter unique challenges given the ball-and-socket configuration of the hip joint, its anatomically abducted and anteverted orientation, and the thin, closely apposed cartilage enveloping the femoral head and acetabulum. Advancements in hip MRI's radial plane, which is acquired through the center of the hip joint, offer a solution. This technology provides true cross-sectional images of the cartilage and labrum perpendicular to the curvature of the joint, thereby mitigating the partial-volume-averaging effects. The integration of 3.0-Tesla high field strength and three-dimensional (3D) acquisition techniques further enhances the capabilities of the radial plane. This combination yields a high signal-to-noise ratio, high spatial resolution, high contrast between intraarticular structures, while minimizing partial-volume-averaging effects. Such improvements potentially facilitate the comprehensive detection of even minor chondral and labral lesions. The capability for multiplanar reconstruction from a single 3D volumetric acquisition further strengthens the usefulness of the radial plane by aiding in precise localization of hip cartilage and labral lesions, in line with hip arthroscopy findings. These advancements have the potential to standardize MRI evaluations and radiographic reporting systems for hip cartilage and labrum, offering precise guidance for hip arthroscopy. This article presents a comprehensive review of radial plane technology applied to the hip MRI, and discusses the morphological assessment and localization of hip cartilage and labral lesions utilizing this advanced imaging technique. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 2.

Comparison of conventional MR arthrography and 3D volumetric MR arthrography in detection of cartilage defects accompanying glenoid labrum pathologies

OBJECTIVES

In this study, we aimed to compare conventional and T1-weighted volumetric magnetic resonance arthrography (MRA) in the diagnosis and grading of glenoid cartilage defects that accompany labral pathologies.

MATERIALS AND METHODS

A total of 79 patients who were prediagnosed with labrum pathologies based on shoulder magnetic resonance imaging (MRI) had MRA and CTA between December 2021 and May 2022. CTA was regarded as reference standard. CTA images were examined by a radiologist experienced in musculoskeletal radiology, and MRA images were examined by two radiologists independently to determine presence, grade, and localization of any glenoid cartilage defect, if present. Sensitivity, specificity, and accuracy were calculated separately for conventional and T1-weighted volumetric MRA. In addition, at the last stage, two observers examined all MRAs together, and the presence of a cartilage defect was decided by consensus, and the overall sensitivity, specificity, and accuracy were calculated.

RESULTS

Cartilage defect was detected on CTAs of 48 (60.75%) cases of among 79 patients with labrum pathology. The sensitivity, specificity, and accuracy of conventional MRA for two examiners were 17-19%, 100-100%, and 49-51%, respectively, while those values were 67-65%, 92-97%, and 84-77%, respectively, for T1-weighted volumetric MRA. Inter-examiner agreement was excellent for diagnosis of cartilage defects on all MRAs. The overall sensitivity, specificity, and accuracy for detection of glenoid cartilage lesions by MRA were 69%, 97%, and 80%, respectively.

CONCLUSION

T1-weighted volumetric MRA seems to demonstrate cartilage defects accompanied with labrum pathologies accurately with high sensitivity, specificity, and excellent inter-examiner agreement.

MR-Neurography of the facial nerve in parotid tumors: intra-parotid nerve visualization and surgical correlation

PURPOSE

One of the most severe complications in surgery of parotid tumors is facial palsy. Imaging of the intra-parotid facial nerve is challenging due to small dimensions. Our aim was to assess, in patients with parotid tumors, the ability of high-resolution 3D double-echo steady-state sequence with water excitation (DE3D-WE) (1) to visualize the extracranial facial nerve and its tracts, (2) to evaluate their relationship to the parotid lesion and (3) to compare MRI and surgical findings.

METHODS

A retrospective study was conducted including all patients with parotid tumors, who underwent MRI from April 2022 to December 2023. Two radiologists independently reviewed DE3D-WE images, assessing quality of visualization of the facial nerve bilaterally and localizing the nerve's divisions in relation to the tumor. MRI data were compared with surgical findings.

RESULTS

Forty consecutive patients were included (M:F = 22:18; mean age 56.3 ± 17.4 years). DE3D-WE could excellently visualize the nerve main trunk and the temporofacial division in all cases. The cervicofacial branch was visible in 99% of cases and visibility was good. Distal divisions were displayed in 34% of cases with a higher visibility on the tumor side (p < 0.05). Interrater agreement was high (weighted kappa 0.94 ± 0.01 [95% CI 0.92-0.97]). Compared to surgery accuracy of MRI in localizing the nerve was 100% for the main trunk, 96% for the temporofacial and 89% for the cervicofacial branches.

CONCLUSIONS

Facial nerve MR-neurography represents a reliable tool. DE3D-WE can play an important role in surgical planning of patients with parotid tumors, reducing the risk of nerve injury.

3D MRI of the Hip Joint: Technical Considerations, Advantages, Applications, and Current Perspectives

Magnetic resonance imaging (MRI) is a common choice among various imaging modalities for the evaluation of hip conditions. Conventional MRI with two-dimensional acquisitions requires a significant amount of time and is limited by partial-volume artifacts and suboptimal fluid-to-cartilage contrast. Recent hardware and software advances have resulted in development of novel isotropic three-dimensional (3D) single-acquisition protocols that cover the volume of the entire hip and can be reconstructed in arbitrary planes for submillimeter assessment of bony and labro-cartilaginous structures in their planes of orientation. This technique facilitates superior identification of small labral tears and other hip lesions with better correlations with arthroscopy. In this review, we discuss technical details related to 3D MRI of the hip, its advantages, and its role in commonly encountered painful conditions that can be evaluated with great precision using this technology. The entities described are femoroacetabular impingement with acetabular labral tears, acetabular dysplasia, avascular necrosis, regional tendinopathies and tendon tears, bursitis, and other conditions.

3D MRI of Articular Cartilage

Osteoarthritis, characterized by the breakdown of articular cartilage and other joint structures, is one of the most prevalent and disabling chronic diseases in the United States. Magnetic resonance imaging is a commonly used imaging modality to evaluate patients with joint pain. Both two-dimensional fast spin-echo sequences (2D-FSE) and three-dimensional (3D) sequences are used in clinical practice to evaluate articular cartilage. The 3D sequences have many advantages compared with 2D-FSE sequences, such as their high in-plane spatial resolution, thin continuous slices that reduce the effects of partial volume averaging, and ability to create multiplanar reformat images following a single acquisition. This article reviews the different 3D imaging techniques available for evaluating cartilage morphology, illustrates the strengths and weaknesses of 3D approaches compared with 2D-FSE approaches for cartilage imaging, and summarizes the diagnostic performance of 2D-FSE and 3D sequences for detecting cartilage lesions within the knee and hip joints.

Elite Rowers Demonstrate Consistent Patterns of Hip Cartilage Damage Compared With Matched Controls: A T2* Mapping Study

BACKGROUND

Rowing exposes the femoral head and acetabulum to high levels of repetitive abutment motion and axial loading that may put elite athletes at an increased risk for developing early hip osteoarthritis.

QUESTIONS/PURPOSES

Do elite rowers demonstrate characteristic hip cartilage lesions on T2 MRI sequences compared with asymptomatic individuals who do not row?

METHODS

This study included 20 asymptomatic rowers (mean age, 23 ± 3 years; nine females, 11 males) who had a minimum of 5 years of intensive (≥ 12 hours/week) training. The recruiting of the rowers took place from the central German federal rowing base, which has inherent intense training and selection requirements to declare these athletes as "elite rowers." We investigated one hip per study participant. MRI was performed on a 3-T scanner. The protocol included standard sequences, a double-echo steady-state sequence, and a multiecho data image combination sequence with inline T2 calculation (= the decay of transverse magnetization arising from molecular interactions [T2] and inhomogeneities in the magnetic field resulting from tissue susceptibility-induced field distortions and variations in the magnet itself), which detects changes in water content and the disruption of collagen structure. Although extrinsic and intrinsic influences on the T2 values including diurnal effects, MR technic-derived variations, and anatomic-related regional disparities need to be taken into account, low T2 values well below 20 ms indicate cartilage degeneration. Cartilage was morphologically analyzed in the anterior, anterosuperior, superoanterior, superior, superoposterior, posterosuperior, and posterior regions of the hip and graded as follows: Grade 0 = normal; Grade 1 = signal changes; Grade 2 = cartilage abrasion; Grade 3 = cartilage loss. Labrum was classified as follows: Grade 0 = normal; Grade 1 = partial tear; Grade 2 = full-thickness tear; Grade 3 = labrum degeneration. The T2 measurement was done through a region of interest analysis. For reliability assessment, morphologic evaluation and T2 measurement were performed by two observers while one observer repeated his analysis with a time interval > 2 weeks. Intra- and interobserver reliability was determined using κ analysis and intraclass correlation coefficients. Control T2 data were derived from a previous study on 15 hips in 15 asymptomatic volunteers of similar ages (seven males and eight females) who were not competitive rowers with similar MR hardware and imaging sequences.

RESULTS

Compared with the control group of asymptomatic volunteers who were not competitive rowers, we noted a high level of labrum and cartilage degeneration in the cohort of elite rowers. In the group of elite rowers, cartilage degeneration was noted in all hips. Regarding the acetabular cartilage, 271 zones could be evaluated. Of those, 44% (120 of 271) were graded normal, 6% (15 of 271) revealed signal alteration, 45% (122 of 271) demonstrated cartilage abrasion, and 5% (14 of 271) were noted to have full-thickness cartilage loss. Morphologic cartilage degeneration in the femoral head was less frequent. T2 values were lower than the control hips in all zones except for the posterior central acetabular zone (global T2 acetabular: 20 ± 6 ms, range, 9-36 ms, 95% confidence interval [CI], 19-21 ms versus 25 ± 5 ms, range, 14-44 ms, 95% CI, 24-25 ms, p < 0.001; global T2 femoral: 23 ± 7 ms, range, 9-38 ms, 95% CI, 22-24 ms versus 27 ± 5 ms, range, 17-45 ms, 95% CI, 26-28 ms, p < 0.001). The difference in T2 between the two study groups was superior in the peripheral zone of the anterosuperior region (16 ± 3 ms; range, 10-22 ms, 95% CI, 15-18 ms versus 26 ms ± 5 ms, range, 18-38 ms, 95% CI, 24-29 ms, p < 0.001).

CONCLUSIONS

We found signs of hip cartilage degeneration to a much greater degree in elite rowers than in asymptomatic controls. Although causation cannot be inferred, this is concerning, and future investigations including controlled longitudinal studies both on elite and nonelite athletes with sufficient cohort size are warranted to clarify our findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Clinical and Radiographic Predictors of Acetabular Cartilage Lesions in Adolescents Undergoing Hip Arthroscopy

BACKGROUND

Acetabular cartilage lesions are a known cause of poor outcomes after hip arthroscopy and are seen regularly among adolescents. However, studies identifying preoperative factors predictive of acetabular cartilage lesions have been limited to adult populations.

PURPOSE

To assess clinical and radiographic predictors of acetabular cartilage lesions in a large cohort of adolescents undergoing hip arthroscopy.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

Patients undergoing hip arthroscopy for idiopathic femoroacetabular impingement or acetabular labral tears at a children's hospital were reviewed. Demographic predictors were analyzed by use of univariate logistic regression with generalized estimating equations. A matched case-control analysis was subsequently performed to identify radiographic predictors of acetabular cartilage lesions through use of univariate and multivariable conditional logistic regression.

RESULTS

Four hundred two patients (446 hips) undergoing hip arthroscopy between 2010 and 2015 were analyzed. Median age was 16.7 years (range, 13.6-19.0) and 72% of patients were female. Ninety-five hips (21%) were found to have an acetabular cartilage lesion at the time of arthroscopic surgery. Age (odds ratio [OR], 1.7; 95% CI, 1.4-2.1), male sex (OR, 2.5; 95% CI, 1.7-5.0), and body mass index (OR, 1.07; 95% CI, 1.01-1.14) were found to be predictive of intraoperative acetabular cartilage lesions. In the matched case-control analysis, femoral alpha angle as calculated on a Dunn lateral radiograph was independently predictive of an intraoperative acetabular cartilage lesion (OR, 1.8; 95% CI, 1.2-2.6). Additionally, the presence of a crossover sign was independently associated with a decreased odds of an acetabular cartilage lesion (OR, 0.3; 95% CI, 0.1-0.7). On multivariate analysis, alpha angle (Dunn lateral) (OR, 2.0; 95% CI, 1.3-3.1) and crossover sign (OR, 0.2; 95% CI, 0.1-0.7) remained independently associated with the presence of an acetabular cartilage lesion. The presence of an acetabular labral tear was not predictive of an associated cartilage lesion (OR, 1.17; 95% CI, 0.39-3.47; P = .78).

CONCLUSION

In an adolescent population undergoing hip arthroscopy, older age, male sex, and higher body mass index were predictive of acetabular cartilage lesions. From an imaging standpoint, increased alpha angle increased the likelihood of an acetabular cartilage lesion whereas the presence of a crossover sign decreased this likelihood. Predicting the presence of an acetabular cartilage lesion is important when considering a hip arthroscopy procedure to facilitate preoperative planning and to more accurately set patient expectations.

Factors increasing risk of failure following hip arthroscopy: a case control study

We aimed to identify factors such as pre-arthroscopy and intra-operative variables that were associated with failure of hip arthroscopy as a joint preserving operation. We performed a retrospective analysis of a database containing 344 consecutive hip arthroscopies performed at our institution. Forty-four hips were identified that underwent a subsequent arthroplasty procedure following their hip arthroscopy (cases). Sixty-six control hips (hip arthroscopy with no subsequent arthroplasty) were randomly selected from the same database. Cases and controls were matched for age, sex and follow-up (P = 0.59, 0.48, 0.10, respectively). Pre-operative radiographs/MRI scans plus intra-operative findings were analysed to identify factors associated with failure. Both a lower centre edge angle and higher acetabular index on pre-operative radiographs were associated with higher rates of failure (P < 0.001). The presence of any acetabular wear at operation was also associated with failure (P < 0.001). Highest rates of failure were seen in hips with both features of dysplasia on pre-operative radiographs and any intra-operative acetabular wear (relative risk: 5, odds ratio: 9.13, P < 0.001). Dysplastic features on pre-operative radiographs and the finding of acetabular wear at hip arthroscopy increase the risk of subsequent arthroplasty. Identification of these features pre-operatively with evolving imaging techniques would improve the results of hip arthroscopy as joint preserving surgery.

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.

Hip Imaging in Athletes: Sports Imaging Series

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016.

3D double-echo steady-state sequence assessment of hip joint cartilage and labrum at 3 Tesla: comparative analysis of magnetic resonance imaging and intraoperative data

OBJECTIVES

To assess the diagnostic accuracy of a high-resolution, three-dimensional (3D) double-echo steady-state (DESS) sequence with radial imaging at 3 Tesla (T) for evaluating cartilage and labral alterations in the hip.

METHODS

Magnetic resonance imaging (MRI) data obtained at 3 T, including radially reformatted DESS images and intraoperative data of 45 patients (mean age 42 ± 13.7 years) who underwent hip arthroscopy, were compared. The acetabular cartilage and labrum of the upper hemisphere of the acetabulum and the central femoral head cartilage were evaluated. Sensitivity, specificity, accuracy, and negative and positive predictive values were determined.

RESULTS

Sensitivity, specificity and accuracy of the DESS technique were 96.7%, 75% and 93.7% for detecting cartilage lesions and 98%, 76.2% and 95.9% for detecting labral lesions. The positive and negative predictive values for detecting or ruling out cartilage lesions were 96% and 78.9%. For labral lesions, the positive and negative predictive values were 97.5% and 80%.

CONCLUSION

A high-resolution, 3D DESS technique with radial imaging at 3 T demonstrated high accuracy for detecting hip cartilage and labral lesions with excellent interobserver agreement and moderate correlation between MRI and intraoperative assessment.

KEY POINTS

• High-resolution, 3D DESS with radial imaging allows accurate cartilage and labrum evaluation. • DESS demonstrated high sensitivity, specificity, accuracy for detecting cartilage and labral lesions. • Highly accurate sequence may influence treatment decisions in patients with hip pain.

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

PURPOSE

To compare the diagnostic accuracy of three-dimensional (3D) fast spin echo (FSE) intermediate-weighed (IW-3D) and 3D hybrid double-echo steady-state T1-weighted sequences (Hy-3D) and two-dimensional (FSE) images (2D) at shoulder MR arthrography (MRA).

MATERIALS AND METHODS

Institutional review board approval was obtained and informed consent was waived for this retrospective study. From September 2011 to October 2014, 102 patients who had undergone 1.5 Tesla MRA of the shoulder, including conventional 2D-FSE and IW-3D and Hy-3D images were included in our study. The mean interval between MRA and surgery was 21 days (range 2-70 days). MR images were retrospectively and independently reviewed by two experienced radiologists blinded to the clinical and surgical data. Supraspinatus tendon (SST), infraspinatus tendon (IST) and subscapularis tendon (SCT) tears, as well as antero-inferior, superior and posterior labral lesions were assessed, using surgery as the reference standard. Each reader's performance in assessing rotator cuff and labrum abnormalities was evaluated using the area under the receiver operating characteristic curve (AUC) and 95% confidence intervals (CIs). The difference was evaluated using a univariate z test. The sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV) and accuracy (Acc) for all types of rotator cuff tears and labral lesions were calculated. A value of p < 0.05 was considered statistically significant. Inter-observer agreement was calculated using kappa statistics.

RESULTS

The difference of diagnostic accuracy achieved was not significant (p > 0.05). In particular, differences in AUC values ranged from 0.002 (p = 0.98) to 0.014 (p = 0.82) as regards the comparison between 2D and IW-3D images, from 0.002 (p = 0.98) to 0.034 (p = 0.08) concerning the comparison between 2D and Hy-3D images and from 0.010 (p = 0.82) to 0.032 (p = 0.09) when comparing Hy-3D to IW-3D images. Accuracy values in evaluating RC lesions and labral lesions were 95.1, 92.1, 91.2, 93.1, 93.1 and 94.1% by reading 2D, Hy-3D and IW-3D images, respectively. The difference of diagnostic accuracy achieved using the datasets analyzed was not significant (p > 0.05). Inter-observer agreement was very good for each of the datasets that were evaluated, with near-perfect agreement for 2D dataset (k = 0.86), Hy-3D (k = 0.81) and IW-3D (k = 0.83).

CONCLUSIONS

The accuracy of IW-3D and Hy-3D images was not significantly higher than the 2D sequences in evaluating RC and labral lesions.

MRI of Labral and Chondral Lesions of the Hip

OBJECTIVE

Unenhanced MRI, indirect MR arthrography, and direct MR arthrography have been used in the radiologic evaluation of patients with suspected labral tears and chondral lesions of the hip. The purpose of this article is to examine the existing evidence for the use of these techniques in patients with hip pain and suspected labral or chondral abnormalities.

CONCLUSION

Evidence from a review of the radiologic literature supports the use of direct MR arthrography over unenhanced MRI and indirect MR arthrography for the detection of labral and cartilage abnormalities in the hip. Although high-resolution unenhanced 3-T MRI appears promising, limited information in the literature supports its use in the detection and characterization of chondrolabral lesions.

Accuracy of 3D dual echo steady state (DESS) MR arthrography to quantify acetabular cartilage thickness

PURPOSE

To deploy and quantify the accuracy of 3D dual echo steady state (DESS) MR arthrography with hip traction to image acetabular cartilage. Clinical magnetic resonance imaging (MRI) sequences used to image hip cartilage often have reduced out-of-plane resolution and may lack adequate signal-to-noise to image cartilage.

MATERIALS AND METHODS

Saline was injected into four cadaver hips placed under traction. 3D DESS MRI scans were obtained before and after cores of cartilage were harvested from the acetabulum; the two MRIs were spatially aligned to reference core positions. The thickness of cartilage cores was measured under microscopy to serve as the reference standard. 3D reconstructions of cartilage and subchondral bone were generated using automatic and semiautomatic image segmentation. Cartilage thickness estimated from the 3D reconstructions was compared to physical measurements using Bland-Altman plots.

RESULTS

As revealed by the automatic segmentation mask, saline imbibed the joint space throughout the articulating surface, with the exception of the posteroinferior region in two hips. Locations where air bubbles were introduced and regions of suspected low density bone disrupted an otherwise smooth automatic segmentation mask. Automatic and semiautomatic segmentation yielded a bias ± repeatability coefficient (95% limits of agreement) of 0.10 ± 0.51 mm (-0.41 to 0.61 mm) and 0.06 ± 0.43 mm (-0.37 to 0.49 mm), respectively.

CONCLUSION

Cartilage thickness can be estimated to within ∼0.5 mm of the physical value with 95% confidence using 3D reconstructions of 3D DESS MR arthrography images. Manual correction of the automatic segmentation mask may improve reconstruction accuracy.

Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T

OBJECTIVE

This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability.

DESIGN

We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI).

RESULTS

Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement.

CONCLUSIONS

Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.

Hip MRI: how useful is intraarticular contrast material for evaluating surgically proven lesions of the labrum and articular cartilage?

OBJECTIVE

The objective of our study was to prospectively compare the diagnostic performance of MR arthrography and conventional MRI with surgical correlation in the same patient for detecting labrum and articular cartilage defects.

SUBJECTS AND METHODS

Twenty-eight patients (mean age, 31.8 years) underwent MR arthrography, conventional MRI, and subsequent hip surgery, which served as the reference standard. Labrum and cartilage defects were evaluated at MRI by two independent readers. A McNemar test and kappa statistics were used for statistical analysis.

RESULTS

At surgery, 31 labral tears were identified. MR arthrography had an advantage over conventional MRI for detecting labral tears at the anterosuperior quadrant (sensitivity of MR arthrography, 81% and 69% for readers 1 and 2, respectively; sensitivity of conventional MRI, 50% for both readers); this difference in performance between MR arthrography and conventional MRI was statistically significant for reader 1 (p = 0.02) but not for reader 2 (p = 0.2). Interobserver agreement for labral tears was higher for MR arthrography (κ = 0.81) than for conventional MRI (κ = 0.63). Surgery showed 31 acetabular cartilage defects and nine femoral cartilage defects. MR arthrography had an advantage over conventional MRI for detecting acetabular cartilage defects (sensitivity of MR arthrography, 71% and 92% for readers 1 and 2, respectively; sensitivity of conventional MRI, 58% and 83%), whereas there was no advantage to using MR arthrography for detecting femoral cartilage defects with statistically significant difference for the acetabular cartilage or femoral cartilage. Interobserver agreement was slightly higher for MR arthrography (κ = 0.50) than for conventional MRI (κ = 0.40) for assessing the acetabular cartilage and was almost identical for the femoral cartilage (κ = 0.62 and 0.63, respectively).

CONCLUSION

MR arthrography was superior to conventional MRI for detecting labral tears and acetabular cartilage defects and showed a higher interobserver agreement. For femoral cartilage lesions, both modalities yielded comparable results.

The evolution and concepts of joint-preserving surgery of the hip

The use of joint-preserving surgery of the hip has been largely abandoned since the introduction of total hip replacement. However, with the modification of such techniques as pelvic osteotomy, and the introduction of intracapsular procedures such as surgical hip dislocation and arthroscopy, previously unexpected options for the surgical treatment of sequelae of childhood conditions, including developmental dysplasia of the hip, slipped upper femoral epiphysis and Perthes’ disease, have become available. Moreover, femoroacetabular impingement has been identified as a significant aetiological factor in the development of osteoarthritis in many hips previously considered to suffer from primary osteoarthritis.

As mechanical causes of degenerative joint disease are now recognised earlier in the disease process, these techniques may be used to decelerate or even prevent progression to osteoarthritis. We review the recent development of these concepts and the associated surgical techniques.

Cite this article: Bone Joint J 2014;96-B:5–18.

Application of advanced magnetic resonance imaging techniques in evaluation of the lower extremity

This article reviews current magnetic resonance imaging (MR imaging) techniques for imaging the lower extremity, focusing on imaging of the knee, ankle, and hip joints. Recent advancements in MR imaging include imaging at 7 T, using multiple receiver channels, T2* imaging, and metal suppression techniques, allowing more detailed visualization of complex anatomy, evaluation of morphologic changes within articular cartilage, and imaging around orthopedic hardware.

MRI abnormalities of the acetabular labrum and articular cartilage are common in healed Legg-Calvé-Perthes disease with residual deformities of the hip

BACKGROUND

Varying degrees of femoral deformity may result as Legg-Calvé-Perthes disease heals. Our aims were to investigate the prevalence of abnormalities of the acetabular labrum and cartilage, using noncontrast magnetic resonance imaging, and to correlate the findings with radiographic deformities that may exist after the healing of Legg-Calvé-Perthes disease.

METHODS

In a sample of ninety-nine patients with healed Legg-Calvé-Perthes disease, anteroposterior and lateral radiographs were used to assess the Stulberg classification, femoral head size and sphericity, femoral neck morphology, and acetabular version. A subgroup of fifty-four patients (fifty-nine hips) underwent noncontrast magnetic resonance imaging of the hip an average of eight years after disease onset. The acetabular labrum was evaluated according to a modified classification system, and the acetabular cartilage was evaluated for the presence of delamination and defects. The association among abnormalities of the acetabular labrum, articular cartilage, and radiographic deformities was assessed.

RESULTS

Abnormalities of the acetabular labrum and cartilage were found on magnetic resonance imaging scans in 75% and 47% of the hips, respectively. An alpha angle of ≥55° was the deformity most significantly associated with labral and cartilage abnormalities, followed by coxa brevis. Coxa magna and a higher greater trochanter showed a significant association with labral abnormalities only. Acetabular retroversion showed an increased risk for labral abnormalities when the alpha angle was normal. When deformities coexisted, the alpha angle showed the greatest relative risk for abnormality.

CONCLUSIONS

On the basis of magnetic resonance imaging evaluation of the hip, labral and cartilage abnormalities were a common finding in patients with healed Legg-Calvé-Perthes disease. Our results suggest that hip deformities are significantly associated with labral and cartilage abnormalities on magnetic resonance imaging, and the main predisposing factor was the asphericity of the femoral head with a reduced femoral head-neck offset.

Diagnosis of acetabular labral tears: comparison of three-dimensional intermediate-weighted fast spin-echo MR arthrography with two-dimensional MR arthrography at 3.0 T

BACKGROUND

Magnetic resonance (MR) arthrography is the ideal imaging modality for the acetabular labrum. Three-dimensional (3D) fast spin-echo (FSE) sequences have similar diagnostic performance as two-dimensional (2D) conventional MR imaging for ligaments, menisci, or bone marrow edema in the knee.

PURPOSE

To compare the diagnostic accuracy and inter-observer reliability of 3D intermediate-weighted FSE sequence and 2D FSE sequences for the diagnosis of acetabular labral tears.

MATERIAL AND METHODS

Institutional review board approval was obtained and informed consent was waived for 45 patients (47 hips) who underwent 3D and 2D MR arthrography and subsequent arthroscopic surgery. The 3D sequences were performed using volumetric intermediate-weighted fast spin-echo imaging with fat suppression (voxel size, 0.6 × 0.6 × 1.2 mm; imaging time, 6 min 38 s). Labral tear was retrospectively and independently evaluated by two radiologists in four areas of the labrum (anterosuperior, posterosuperior, anteroinferior, and posteroinferior) on 3D and 2D FSE sequences. Statistical differences between the sensitivity and specificity of the methods were analyzed with the McNemar test, using arthroscopic findings as the reference standard. Inter-observer agreement was calculated using kappa statistics.

RESULTS

Arthroscopic findings confirmed labral tears at 40 anterosuperior, 23 posterosuperior, 0 anteroinferior, and 2 posteroinferior quadrants. Sensitivity and specificity were 74% and 89% for 2D FSE sequences, and 78% and 92% for 3D FSE sequences, respectively. Sensitivities and specificities for the methods were not different statistically (P > 0.05). Inter-observer agreement for labral tear was substantial for 2D FSE sequences (κ = 0.774) and almost perfect for 3D FSE sequences (κ = 0.842).

CONCLUSION

3D intermediate-weighted FSE MR arthrography is excellent for diagnosing acetabular labral tears. Sensitivity, specificity, and inter-observer reliability were similar to conventional 2D MR arthrography. For evaluation of the labrum, 3D FSE MR arthrography is more time-efficient than 2D FSE MR arthrography.

Three-dimensional MRI of the musculoskeletal system

OBJECTIVE

The purposes of this review are to describe commonly available 3D MRI techniques and to discuss the literature to date regarding the utility of such techniques in the assessment of internal derangement of joints.

CONCLUSION

Long acquisition and postprocessing times and limited contrast characteristics have generally prohibited routine use of 3D MRI in clinical practice. However, technical advances, including higher-field-strength MRI systems, high performance gradients, high-resolution multichannel coils, and pulse sequences with shorter acquisition times, have made feasible 3D isotropic MRI with reasonable acquisition times.

A new method to analyze dGEMRIC measurements in femoroacetabular impingement: preliminary validation against arthroscopic findings

OBJECTIVE

To validate a new method to analyze delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) measurements in the hip for early assessment of cartilage defects in femoroacetabular impingement (FAI).

METHODS

We performed a retrospective review of 10 hips in 10 FAI patients, who underwent hip arthroscopy. T1-weighted images and dGEMRIC T(1) maps were acquired at 1.5 T on coronal planes, including the anterior-superior, superior, posterior-superior hip cartilage. For all slices, a region of interest (ROI) was defined over the central portion of the femoral cartilage, assumed to be healthy, and T1 values (x) were transformed to standard scores (z) using z = (x -μ)/σ, where μ and σ are the average and standard deviation of T1 in the femoral ROI. Diagnostic performance of the resulting standardized dGEMRIC maps was evaluated against intraoperative findings and compared with that of a previously proposed dGEMRIC analysis as well as morphologic assessment.

RESULTS

Assuming z = -2 or z = -3 as the threshold between normal and degenerated cartilage, sensitivity, specificity and accuracy were 88%, 51% and 62%, and 71%, 63% and 65%, respectively. By using T1 = 500 ms as single threshold for all dGEMRIC T1 maps, these values became 47%, 58% and 55%, whereas they were 47%, 79% and 70% for morphologic evaluation.

CONCLUSIONS

Standardized dGEMRIC can increase the sensitivity in detecting abnormal cartilage in FAI and has the potential to improve the clinical interpretation of dGEMRIC measurements in FAI, by removing the effect of inter- and intra-patient T1 variability.

Imaging of snapping phenomena

Snapping phenomena result from the sudden impingement between anatomical and/or heterotopical structures with subsequent abrupt movement and noise. Snaps are variously perceived by patients, from mild discomfort to significant pain requiring surgical management. Identifying the precise cause of snaps may be challenging when no abnormality is encountered on routinely performed static examinations. In this regard, dynamic imaging techniques have been developed over time, with various degrees of success. This review encompasses the main features of each imaging technique and proposes an overview of the main snapping phenomena in the musculoskeletal system.

MR imaging of early hip joint degeneration

MR imaging is one of the most commonly used imaging techniques to evaluate patients with hip pain. Intra-articular abnormalities of the hip joint are better assessed with recent advances in MR imaging technology, such as high-field strength scanners, improved coils, and more signal-to-noise ratio-efficient sequences. This article discusses the causes of early hip joint degeneration and the current use of morphologic and physiologic MR imaging techniques for evaluating the articular cartilage of the hip joint. The article also discusses the role of MR arthrography in clinical cartilage imaging.

Routine 3D magnetic resonance imaging of joints

Due to its high spatial resolution and excellent tissue contrast, magnetic resonance imaging (MRI) has become the most commonly used imaging method to evaluate joints. Most musculoskeletal MRI is performed using 2D fast spin-echo sequences. However, 3D sequences have also been used for joint imaging and have the advantage of acquiring thin continuous slices through joints, which reduces the effects of partial volume averaging. With recent advances in MR technology, 3D sequences with isotropic resolution have been developed. These sequences allow high-quality multiplanar reformat images to be obtained following a single acquisition, thereby eliminating the need to repeat sequences with identical tissue contrast in different planes. Preliminary results on the diagnostic performance of 3D isotropic resolution sequences are encouraging. However, additional studies are needed to determine whether these sequences can replace currently used 2D fast spin-echo sequences for providing comprehensive joint assessment in clinical practice.

Radiology

Hip and groin pain are a common complaint among athletes of all ages, and may result from an acute injury or from chronic, repetitive trauma. Hip injuries can be intraarticular, extraarticular, or both. Labral abnormalities may occur in asymptomatic patients as well as in those with incapacitating symptoms and signs. Athletic hip injury leading to disabling intraarticular hip pain most commonly involves labral tear. The extraarticular causes are usually the result of overuse activity, leading to inflammation, tendonitis, or bursitis. In clinical practice, the term athletic pubalgia is used to describe exertional pubic or groin pain.

Magnetic resonance imaging of hip joint cartilage and labrum

Hip joint instability and impingement are the most common biomechanical risk factors that put the hip joint at risk to develop premature osteoarthritis. Several surgical procedures like periacetabular osteotomy for hip dysplasia or hip arthroscopy or safe surgical hip dislocation for femoroacetabular impingement aim at restoring the hip anatomy. However, the success of joint preserving surgical procedures is limited by the amount of pre-existing cartilage damage. Biochemically sensitive MRI techniques like delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC) might help to monitor the effect of surgical or non-surgical procedures in the effort to halt or even reverse joint damage.

Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls

With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint.This review outlines the current status of dGEMRIC for assessment of hip joint cartilage. Practical modifications of the standard technique including three-dimensional (3D) dGEMRIC and dGEMRIC after intra-articular gadolinium instead of iv-dGEMRIC will also be addressed.

Intravenous versus intra-articular delayed gadolinium-enhanced magnetic resonance imaging in the hip joint: a comparative analysis

OBJECTIVE

The purpose of this study was to investigate whether T1-mapping of hip joint with intra-articular delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (ia-dGEMRIC) is comparable to the already established intravenous (iv)-technique for assessing different grades of cartilage degeneration.

MATERIALS AND METHODS

The study cohort consisted of 53 patients with symptomatic femoroacetabular impingement (FAI) that were randomly recruited for either iv-dGEMRIC or ia-dGEMRIC studies. RI was performed in supine position at a 1.5 Tesla (T) system (Magnetom Avanto, Siemens, Erlangen, Germany) using a body matrix-phased array coil. Twenty-six patients (18 males, 8 females; mean age +/- standard deviation [SD]: 32.1 +/- 8.8 years, range: 17-49 years) underwent iv-dGEMRIC whereas 27 patients (17 males, 10 females; mean age 34.0 +/- 10.8 years, range: 13.0-57 years) underwent ia-dGEMRIC mapping. On average patients suffered from FAI for 23.9 +/- 20.9 months in the iv-dGEMRIC group (range: 5-108 months) whereas FAI was symptomatic for 20.9 +/- 25.2 months in the ia-dGEMRIC group (range: 3-120 months). Patient demographics and symptomatology in both groups were not statistically different.

RESULTS

Mapping with both techniques (iv and ia) demonstrated appropriately similar differences between various grades of cartilage degeneration. Overall, there was no significant difference between iv-dGEMRIC and ia-dGEMRIC T1 mean values in all grades of cartilage findings (P: 0.394, 0.400, and 0.173). Of note, the T1 values after iv-dGEMRIC were higher (544.3 +/- 104.2 milliseconds) in regions with cartilage damage extent <0.75 cm than in regions where no damage was noted (535.7 +/- 112.4 milliseconds). After ia-dGEMRIC the T1 values were similar (521.2 +/- 125.1 milliseconds vs. 521.1 +/- 94.3 milliseconds).

CONCLUSIONS

Intravenous contrast remains the standard method of contrast administration in the current scenario when dGEMRIC imaging is performed. Our results demonstrate that the information and mapping values obtained by the ia-technique are similar to those of the iv-technique. The intravenous route can have its own problems in certain patients with impaired renal function tests or when parenteral access is an issue in many patients. Intra-articular technique could be a good alternative in such cases whereas maintaining the quality of imaging and obtained information. Thus, in well-selected cases ia-dGEMRIC mapping may be a potential alternative to iv-dGEMRIC for hip joint cartilage analysis.

LEVEL OF EVIDENCE

Prospective case series, Diagnostic study comparing different modalities of assessing status of hip joint cartilage: Level II evidence.

3D double-echo steady-state with water excitation MR imaging of the intraparotid facial nerve at 1.5T: a pilot study

BACKGROUND AND PURPOSE

The intraparotid facial nerve is difficult to delineate using conventional MR sequence. Our aim was to assess the value of 3D DESSWE MR imaging in depicting the normal anatomy of the intraparotid facial nerve.

MATERIALS AND METHODS

A 3D-DESSWE sequence was performed with optimum parameters in 18 healthy volunteers on a 1.5T MR imaging unit. The data obtained were reconstructed in relation to the course of the facial nerve by using the MPR and thin-section MIP programs. Images acquired were analyzed by 2 neuroradiologists. They made the initial evaluations independently but resolved inconsistencies by collaborative review and consensus agreement. The certainty of identifying the intraparotid facial nerve was scored and recorded on an arbitrary scale of 0-2. The lengths of the facial nerves were measured; CNRs of the facial nerves and parotid ducts were calculated. Statistical evaluation of the results was achieved by the 2-tailed Wilcoxon test, ANOVA, and a paired t test.

RESULTS

In all subjects, 3D DESSWE images provided a reliable definition of the normal facial nerve anatomy bilaterally. There were no significant differences between scores, lengths, and CNRs of bilateral facial nerves (P > .05). The intraparotid facial nerve, parotid ducts, and retromandibular vein showed high signal intensity while the surrounding soft tissue showed relatively low signal intensity. The signal intensity between the facial nerves and parotid ducts was significantly different (P < .01); but no differences could be obtained for the CNRs between the 2 structures (P > .05).

CONCLUSIONS

The 3D DESSWE sequence can display the intraparotid course of the normal facial nerve, including the relationship between the facial nerve and the parotid duct.

Comparison of pre-operative dGEMRIC imaging with intra-operative findings in femoroacetabular impingement: preliminary findings

OBJECTIVES

To study standard MRI and dGEMRIC in patients with symptomatic FAI undergoing surgical intervention and compare them with intra-operative findings to see if they were corroborative.

METHODS

Sixteen patients with symptomatic FAI that warranted surgical intervention were prospectively studied. All patients underwent plain radiographic series for FAI assessment followed by standard MRI and dGEMRIC. Subsequently, patients were surgically treated with safe dislocation and the joint was evaluated for any macroscopic signs of damaged cartilage. Data were statistically analyzed.

RESULTS

A total of 224 zones in 16 patients were evaluated. One hundred and sixteen zones were intra-operatively rated as normal with mean T1 values of 510.1 ms ± 141.2 ms. Eighty zones had evidence of damage with mean T1 values of 453.1 ms ± 113.6 ms. The difference in these T1 values was significant (p = 0.003). Correlation between standard MRI and intra-operative findings was moderate (r = 0.535, p < 0.001). Intra-operative findings revealed more damage than standard MRI. On standard MRI, 68.6% zones were graded normal while 31.4% had evidence of damage. On intra-operative visualization, 56.4% zones were graded normal and 43.6% had evidence of damage. Correlation between dGEMRIC and intra-operative findings turned out to be weak (r = 0.114, p < 0.126). On T1 assessment 31.4% of zones were graded as normal and 68.6% as damaged.

CONCLUSIONS

dGEMRIC was significantly different between normal and affected cartilage based on intra-operative assessment. The correlation for morphological findings was limited, underestimating defects. By combining morphological with biochemical assessment dGEMRIC may play some role in the future to prognosticate outcomes and facilitate surgical planning and intervention.

Three-dimensional magnetic resonance imaging of joints

Magnetic resonance (MR) imaging is one of the most commonly used imaging modality for evaluating patients with joint pain. Musculoskeletal MR protocols at most institutions consist of 2-dimensional fast spin echo (FSE) sequences repeated in multiple planes. Three-dimensional sequences have also been used to evaluate the musculoskeletal system and have many potential advantages over 2-dimensional FSE sequences. Three-dimensional sequences acquire thin continuous slices through joints with high in-plane spatial resolution, which minimize the effects of partial volume averaging. Newly developed 3-dimensional isotropic resolution sequences can also be used to create high-quality multiplanar reformat images that allow joints to be evaluated in any orientation after a single acquisition. Preliminary results on the use of 3-dimensional isotropic resolution sequences for evaluating the musculoskeletal system are encouraging. However, additional studies are needed to document the advantages of 3-dimensional sequences before they can replace currently used 2-dimensional FSE sequences for evaluating the musculoskeletal system in clinical practice.

Clinical cartilage imaging of the knee and hip joints

OBJECTIVE

MRI is commonly used to evaluate the articular cartilage of the knee and hip joints in clinical practice. This article will discuss the advantages and limitations of currently available MRI techniques for evaluating articular cartilage.

CONCLUSION

Because of its high spatial resolution, multiplanar capability, and excellent tissue contrast, MRI is the imaging technique of choice for evaluating the articular cartilage of the knee and hip joints.

Acetabular osteochondroplasty and simultaneous reorientation: background and validation of concept

Most hips with femoroacetabular impingement (FAI) have combinations of femoral and acetabular abnormalities, including acetabular deficiency in some cases. Other impinging hips have large acetabular hyaline cartilage lesions that, when treated by resection, lead to acetabular deficiency and the need for a subsequent reorientation to improve coverage. Ideally, large cartilage lesions could be identified preoperatively and treated with 1 procedure. Therefore, a single operative approach that allows for both femoral and acetabular osteochondroplasty where needed, as well as simultaneous acetabular reorientation, is advantageous. We hypothesized that the addition of traction and dry arthroscopy via the Smith-Petersen approach at the time of periacetabular osteotomy could allow for the diagnosis and treatment of intra-articular labral and hyaline cartilage lesions and simultaneous acetabular reorientation. To validate this concept, we performed the procedure on cadaveric hips and subsequently treated a series of patients successfully (4 hips with limited anterior debridement and dry arthroscopy and 1 hip with a simultaneous periacetabular osteotomy). There were no intra- or postoperative complications in the series of 5 hips. The addition of traction and dry arthroscopy can permit the diagnosis and treatment of intra-articular lesions in reorienting periacetabular osteotomy. This enables the surgeon to address both acetabular cartilage and labral lesions, as well as idealizing acetabular orientation and coverage in 1 setting with less morbidity.

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

Magnetic resonance(MR) imaging is the reference imaging technique in the evaluation of hip abnormalities. However, in some pathological conditions-such as lesions of the labrum, cartilaginous lesions, femoroacetabular impingement, intra-articular foreign bodies, or in the pre-operative work-up of developmental dysplasia of the hip-intra-articular injection of a contrast medium is required to obtain a precise diagnosis. This article reviews the technical aspects, contraindications, normal appearance and potential pitfalls of MR arthrography, and illustrates the radiological appearance of commonly encountered conditions.

MRI of hip osteoarthritis and implications for surgery

Osteoarthritis of the hip joint is caused by a combination of intrinsic factors and extrinsic factors. Different surgical techniques are being performed to delay or halt osteoarthritis. Success of salvage procedures of the hip depends on the existing cartilage and joint damage before surgery; the likelihood of therapy failure rises with advanced osteoarthritis. For imaging of intra-articular hip pathology, MR imaging represents the best technique because of its ability to directly visualize cartilage, superior soft tissue contrast, and the prospect of multidimensional imaging. This article gives an overview on the standard MR imaging techniques used for diagnosis of hip osteoarthritis and their implications for surgery.