MR imaging of the shoulder. Impingement and instability-related abnormalities

In addition to the case history and the clinical examination, MR imaging has an important role in the diagnosis and differential diagnosis of numerous shoulder abnormalities and in the investigation of chronic shoulder pain. Important indications for MR imaging are any conditions or symptoms making assessment of the rotator cuff and the labrocapsular complex necessary. Assessment of the rotator cuff muscles, in particular, is crucial. The value of MR arthrography, which is still controversial, is discussed. The greatest potential benefit of MR arthrography is the accurate evaluation of subtle rotator cuff abnormalities and shoulder instability-related lesions, and the assessment of pathologic conditions of the long biceps tendon. This paper describes the most common pathologic findings of the shoulder joint and describes how the relevant findings are reported and quantified for the orthopaedic shoulder surgeon.     

Magnetresonanztomographie der Schulter

In addition to the case history and the clinical examination, MR imaging has an important role in the diagnosis and differential diagnosis of numerous shoulder abnormalities and in the investigation of chronic shoulder pain. Important indications for MR imaging are any conditions or symptoms making assessment of the rotator cuff and the labrocapsular complex necessary. Assessment of the rotator cuff muscles, in particular, is crucial. The value of MR arthrography, which is still controversial, is discussed. The greatest potential benefit of MR arthrography is the accurate evaluation of subtle rotator cuff abnormalities and shoulder instability-related lesions, and the assessment of pathologic conditions of the long biceps tendon. This paper describes the most common pathologic findings of the shoulder joint and describes how the relevant findings are reported and quantified for the orthopaedic shoulder surgeon.     

Imaging of degenerative and posttraumatic disease in the shoulder joint with ultrasound

This article reviews the examination technique of shoulder ultrasound, normal and abnormal ultrasound findings in acute (posttraumatic) and chronic (degenerative) lesions. Moreover, it reviews the effectiveness of ultrasound in relation to magnetic resonance (MR) imaging. Most authors report that full-thickness tears of the supraspinatus can reliably be diagnosed by ultrasound. However, the simple diagnosis of a full-thickness rotator cuff tear is no longer sufficient for surgical management. The precise localization and size of rotator cuff tears as well as the extent of muscle degeneration is important for surgical planning. For this aspect and for partial-thickness tears of the supraspinatus, for subscapularis lesions as well as for lesions of the long biceps tendons there is no consensus regarding the diagnostic value of ultrasound. To the present, ultrasound (contrary to MR imaging) has failed to demonstrate that it consistently influences the clinician's degree of confidence in the clinical diagnosis or the treatment plan. Therefore, some orthopedic surgeons prefer MR imaging to ultrasound in the evaluation of rotator cuff tears and other abnormalities of the glenohumeral joint. Moreover, MR imaging, especially when combined with arthrography, represents a one-step investigation, which not only allows for assessment of rotator cuff lesion but also of lesions of the labrum (Bankart lesions, SLAP lesions), the joint capsule and the biceps tendon. It also demonstrates muscle atrophy, which represents an important predictor of surgical outcome in rotator cuff repair.     

Rotator cuff lesions: evaluation with RM and US

Physical and instrumental examination of the patients with an "aching shoulder" is often difficult and a positive out-come of surgical treatment may be impaired by the late diagnosis of long-standing rotator cuff lesions causing tendon adhesions and muscle atrophy. The authors report the results obtained in 25 selected patients with an aching shoulder examined with arthrography, real-time ultrasound (US) with a 5 MHz linear probe, and high-field (1.5 T) Magnetic Resonance (MR) imaging. Arthrography was able to demonstrate a cuff tear in 14/25 cases; US detected signs of tear in 14/25 (1 false negative); MR imaging showed a cuff lesion in 16/25 patients, and in one case allowed a partial cuff tear to be demonstrated, which had not been visualized with arthrography. MR imaging could also demonstrate other signs of periarticular pathologies (tendinitis, longhead of biceps inflammation, and bursitis) that may represent the early stages of the inflammatory-degenerative process underlying most of cuff lesions. The high diagnostic accuracy of US (95%) is stressed in the detection of cuff tears, in patients with an aching shoulder; as for questionable cases at US, MR imaging is indicated as a valid alternative to arthrography, which is more invasive and less accepted by the patients.     

Diagnosis of tears in rotator-cuff-injuries

Pathology of the rotator cuff is the cause of most common problems at the shoulder joint. Acute injuries are not as frequent as chronic cuff disease, but often they aggravate inflammatory or degenerative tendon alterations, even if they are of minor severity. Traumatic rotator cuff tears predominantly affect the supraspinatus tendon or the rotator interval. The subscapularis tendon is involved in anterior dislocations of the glenohumeral joint or in direct trauma. Plain film radiography still remains the base of all further imaging studies. If only full-thickness tears must be ruled out, double-contrast arthrography and ultrasound are acceptable imaging modalities. However, the former has a drawback in being invasive and does not detect partial tears at the bursal site of the cuff or rotator cuff tendinopathy, whereas the latter heavily depends on the experience of the radiologist and is restricted to the rotator cuff. Nowadays the most comprehensive imaging method is magnetic resonance (MR) imaging. MR imaging enables the detection or exclusion of complete rotator cuff tears with a reasonable accuracy and is also suitable to diagnose further pathologies of the shoulder joint. MR arthrography is valuable in the detection of subtle anatomic details and further improves the differentiation of rotator cuff diseases. Although in comparison MR imaging is still the most expensive imaging method, its high negative predictive value for the diagnosis of complete rotator cuff tears and its reliability evaluating different shoulder joint pathologies make it the preferred imaging modality.     

MR imaging of rotator cuff tears: is there a diagnostic benefit of shoulder exercise prior to imaging

The purpose of this study was to determine if shoulder exercise prior to MR imaging accentuates findings related to rotator cuff tears. In 32 consecutive patients undergoing MR imaging to evaluate the rotator cuff, after routine MR examination, the joint was moved by active or passive exercise (circumduction, including abduction, if possible) in an attempt to redistribute any joint fluid. The exercise was performed according to pain tolerance and for no longer than 4 minutes. The coronal oblique fast spin-echo T2-weighted images of these patients performed before exercise were reviewed by consensus agreement of two musculoskeletal radiologists who were blinded to clinical information. The appearance of the rotator cuff tendons and the distribution of fluid in the glenohumeral joint were determined. The identical postexercise MR images then were placed alongside the corresponding preexercise MR images, and a direct comparison of findings was made with regard to any change in the appearance of the rotator cuff or joint fluid by consensus opinion of the same two radiologists. Five patients (five shoulders) could not perform exercise because of pain. In the remaining 27 patients (27 shoulders), changes in the location of joint fluid were seen when the preexercise and postexercise images were reviewed together, the diagnosis of partial rotator cuff tear (n = 8) was changed to normal in two cases, and the diagnosis of partial tear was made with more confidence in one case. The diagnoses of normal rotator cuff (n = 16) and complete rotator cuff tear (n = 3) were unchanged. Eight patients had arthroscopy; in each of these, the preexercise and postexercise images showed similar results, and proved to be correct surgically (six normal, one partial rotator cuff tear, and one complete rotator cuff tear). Although postexercise MR images show changes in the distribution of joint fluid when compared to preexercise images, the diagnostic benefits of the postexercise images in the analysis of the rotator cuff appear to be limited.     

肩关节损伤的MR影像诊断

目的 探讨常规MRI和MR间接关节造影对肩关节损伤的诊断价值.方法 回顾分析经关节镜证实的90例肩关节损伤患者肩关节常规MRI和MR问接关节造影表现,其中肩袖病变组57例、盂肱关节不稳组33例.对常规MRI和MR间接关节造影诊断结果进行Fisher确切概率法比较.结果 (1)肩袖病变组中MR间接关节造影37例,显示部分撕裂10例,1例漏诊;显示完全撕裂17例,2例误诊,7例肩袖无撕裂.MR间接关节造影显示部分撕裂的敏感度、特异度、准确度分别为90.9%(10/11)、92.3%(24/26)、91.9%(34/37);显示完全撕裂的敏感度、特异度、准确度分别为89.5%(17/19)、94.4%(17/18)、91.9%(34/37).MR间接关节造影诊断肩袖部分及完全撕裂的敏感度及准确度均高于常规MRI(P<0.05).(2)盂肱关节不稳组中,盂唇损伤26例,Hill-sachs病变27例、反Hill-sachs病变2例、骨陛Bankart损伤7例、关节囊损伤18例.间接关节造影20例,显示盂唇损伤14例,1例漏诊,5例正常.MR间接关节造影显示盂唇损伤的敏感度、特异度、准确度分别为93.3%(14/15)、100.0%(5/5)、95.0%(19/20).前者诊断盂唇损伤的敏感度及准确度明显高于常规MRI(P<0.05).结论 MR检查特别是MR间接关节造影能够准确显示肩关节常见病变及相关组织的病理发展过程,为临床诊断及治疗提供影像学依据.     

Shoulder magnetic resonance imaging

MRI provides excellent soft tissue contrast and allows for multiplanar imaging in anatomic planes. Because of these advantages MRI has become the study of choice for imaging of shoulder pathology. Some structures, such as the rotator cuff, humeral head contour, and glenoid shape, are evaluated well with conventional MRI. When more sensitive evaluation of the labrum, capsule, articular cartilage, and glenohumeral ligaments is required or when a partial-thickness rotator cuff tear is suspected,magnetic resonance arthrography with intra-articular contrast can be performed. For MR arthrography contrast is injected directly into the glenohumeral joint. This article reviews the appearances of normal anatomic structures in MRI of the shoulder and disorders involving the rotator cuff and glenoid labrum.     

Efficacy of ultrasonography-guided shoulder MR arthrography using a posterior approach

Aim  

Shoulder MR arthrography has an important role in the assessment of rotator cuff lesions, labral tears, glenohumeral ligaments, rotator interval lesions, and postoperative shoulder status. Injection in direct MR arthrography can be performed with palpation, fluoroscopy, ultrasonography (US), or MRI. Recently, the posterior approach is the preferred method due to the presence of fewer stabilizers, absence of important articular structures and less extravasation, has been advocated. Our aim was to assess the efficacy of US-guided MR arthrography via a posterior approach on the glenohumeral joint.     

Ultrasonographic and MR diagnosis of rotator cuff disorders & shoulder joint instability

Objective

To evaluate the role and efficacy of U/S and MR in diagnosis of rotator cuff disorders and shoulder joint instability.

Patients and methods

This study included 30 patients with shoulder pain and/or movement limitation. They underwent shoulder U/S examination followed by MR examination. The U/S & MR diagnostic criteria of each patient were analyzed, compared and correlated with arthroscopic and/or orthopedic surgical findings.

Results

15 patients had with rotator cuff disorders 15/30 (50%) and 11 patients had shoulder instability 11/30 (36.7%). Out of 15 patients with rotator cuff disorders, 12 patients had rotator cuff tears 12/15 (80%) and 3 patients had tendenosis 3/15(20%). The supraspinatus muscle was involved in all cases (100%), without a significant comparable difference between U/S and MR. Out of 11 patients with shoulder instability 8 patients had anterior labral tear 8/11 (72.7%); 2 patients had superior labral tear 2/11 (18.2%) and only one patient with posterior labral tear.

Conclusion

U/S and MRI are valid diagnostic modalities in detecting, characterizing and discriminating the rotator cuff disorders, with no significant comparable difference. U/S has many challenges in patients with shoulder instability, while MR provides accurate diagnosis even without contrast.     

Low-field MR arthrography of the shoulder joint: technique,indications, and clinical results

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting. Electronic Publication     

MRI在肩关节疼痛疾病诊断中的应用

目的：探讨MRI在肩关节疼痛疾病诊断和鉴别诊断中的应用价值。材料和方法：对28例28侧肩关节疼痛患者，使用0．5T的MR仪行肩关节磁共振检查，分析MRI表现的形态学特点。结果：28例肩关节MRI扫描发现：肩袖完全撕裂、肩袖部分撕裂、肌腱炎、肩袖钙化、肩锁关节积液、肱二头肌腱长头腱鞘炎、肌膜脱位等。6例经手术证实，22例行保守治疗。结论：MRI由于其多平面成像的能力和优良的软组织对比，能详细显示肩关节的解剖结构，敏感地发现软组织异常，对肩关节疼痛的诊断和鉴别诊断有较高的应用价值。     

Magnetic resonance imaging of sports-related injuries to the shoulder: impingement and rotator cuff

MR imaging provides clinically useful information in detecting and characterizing sports-related pathology of the rotator cuff and other shoulder disorders in a non-invasive fashion. Complete and partial tears of the rotator cuff, as well as factors contributing to impingement, can be detected and characterized with MR imaging. The size and location of complete tears of the rotator cuff can be accurately determined with MR imaging.     

Ultrasound of the rotator cuff with MRI and anatomic correlation

Magnetic resonance imaging and high-resolution ultrasound (US) are frequently used for the detection of rotator cuff tears. The diagnostic yield of US is influenced by several factors as technique, knowledge of the imaging characteristics of anatomic and pathologic findings and of pitfalls. The purpose of this article is to illustrates that the standardized high-resolution US examination of the shoulder covers the entire rotator cuff and correlates with MR imaging and anatomic sections.     

Normal MR imaging anatomy of the rotator cuff tendons, glenoid fossa, labrum, and ligaments of the shoulder

The shoulder is commonly imaged using MR imaging, with or without intraarticular contrast medium. Some anatomic structures, such as the rotator cuff tendons and bony components, can be assessed without arthrographic technique, whereas the glenohumeral ligaments and labrum require arthrographic technique for more accurate assessment. In either case, an understanding of the normal anatomy of the shoulder with regard to bony and soft tissue structures is essential for MR imaging interpretation. In this article we discuss normal anatomy and variations of the glenohumeral joint(bone and soft tissues), rotator cuff tendons, and coracoacromial arch.     

Indirect MR arthrography of the unexercised glenohumeral joint in patients with rotator cuff tears.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic utility of indirect MR arthrography of the unexercised glenohumeral joint in patients with rotator cuff tears confirmed by arthroscopy or arthrotomy as the gold standard. METHODS: Twenty-six patients underwent conventional MR imaging and indirect MR arthrography of the stationary glenohumeral joint using a wrap-around surface coil. Unenhanced T1-weighted spin echo/T2-weighted fast spin echo sequences and T1-weighted gradient echo sequences, adding spectral fat suppression after intravenous administration of contrast medium, were performed in the oblique coronal and oblique sagittal planes. Images were analyzed by three experienced radiologists in consensus. Levels of diagnostic confidence were evaluated using a four-point scale of diagnostic certainty. RESULTS: Performing indirect MR arthrography of the unexercised shoulder leads to a diagnostically efficient enhancement of joint fluid (120% at 4 minutes and 145% at 8 minutes after intravenous injection of gadodiamide). In terms of soft tissue delineation, characterization of rotator cuff tears was significantly improved by using enhanced fat-suppressed T1-weighted gradient echo sequences compared with conventional MR imaging. CONCLUSIONS: Indirect MR arthrography without glenohumeral joint exercise in the diagnosis of rotator cuff tears is feasible and represents a more convenient and less time-consuming alternative to indirect MR arthrography after joint exercise.     

Rotator cuff: evaluation with US and MR imaging.

Magnetic resonance (MR) and ultrasound (US) imaging are currently touted for assessment of rotator cuff disease. Optimum clinical imaging techniques include use of (a) a 1.5-T MR imaging unit with small planar coils, proton-density-weighted and T2-weighted fast spin-echo sequences, and 10-12-cm fields of view (yielding 400-470 x 500-625-microm in-plane spatial resolution) and (b) a state-of-the-art commercial US unit with insonation frequencies of 9-13 MHz (yielding 200-400-microm axial and lateral resolution). Proper diagnosis requires familiarity with normal anatomic characteristics and imaging pitfalls. Care must be taken to avoid sonographic tendon anisotropy and MR imaging magic angle effects, which can be misinterpreted as rotator cuff tear. At MR imaging, a complete cuff tear typically appears as either a hyperintense defect or a tendinous avulsion that extends from the bursal to the articular side of the cuff; a partial cuff tear typically appears as a focal hyperintense region that contacts only one surface of the cuff. Complete and partial tears manifest with a wide spectrum of findings at US. MR imaging and US are effective for evaluating rotator cuff injuries, with high reported accuracies for detection of complete tears but more disparate results for detection of partial tears.     

The effectiveness of diagnostic imaging methods for the assessment of soft tissue and articular disorders of the shoulder and elbow

There are no clear guidelines for diagnostic imaging of articular and soft tissue pathologies of the shoulder and elbow. Several methods are used, including magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA) and ultrasound (US). Their cost-effectiveness is still unclear. We performed a meta-analysis of the relevant literature and discussed the role of MR imaging of the shoulder and elbow compared with other diagnostic imaging modalities. For the shoulder impingement syndrome and rotator cuff tears, MRI and US have a comparable accuracy for detection of full-thickness rotator cuff tears. MRA and US might be more accurate for the detection of partial-thickness tears than MRI. Given the large difference in cost of MR and US, ultrasound may be the most cost-effective diagnostic method for identification of full-thickness tears in a specialist hospital setting (Evidence level 3). Both MRA and CT arthrography (CTA) are effective methods for the detection of labrum tears. More recently, multidetector CTA has offered the advantages of thinner slices than with MRA in a shorter examination time. Still, MRA has the advantage towards CTA to directly visualize the affected structures with a better evaluation of extent and location and to detect associated capsuloligamentous injuries. For the elbow pathologies, plain MRI or MRA have the advantage towards CTA to detect occult bone injuries. CTA is better for the assessment of the thin cartilage of the elbow. Both US and MRI are reliable methods to detect chronic epicondylitis; US is more available and far more cost-effective (Evidence level 2). MRA can differentiate complete from partial tears of the medial collateral ligament. US or MRI can detect partial and complete biceps tendon tears and/or bursitis. MRI can provide important diagnostic information in lesions of the ulnar, radial, or median nerve.     

常规MRI及MRI肩关节造影在肩袖撕裂中的应用

目的:探讨常规MRI及MRI肩关节造影在肩袖撕裂诊断中的价值。方法:226例肩关节损伤的患者,分别行常规MRI及MRI肩关节造影检查,以近期肩关节镜检查为金标准,对比2种检查方法的敏感性及特异性。结果:常规MRI对肩袖撕裂诊断的敏感性为70.8%(17/24),特异性100%(2/2),准确性65.4%(17/26);MRI肩关节造影对肩袖撕裂的敏感性为95.8%(23/24),特异性100%(2/2),准确性88.5%(23/26)。两者的诊断敏感性差异有统计学意义(P=0.016)。结论:MRI肩关节造影可以显著提高肩袖撕裂诊断的敏感性。