肩袖损伤MRI与关节镜下表现对比的初步研究

刘佳超 陈建海 黄伟 王天兵 姜保国

通讯作者：姜保国,Email:jiangbaoguo@vip.sina.com

【摘要】目的研究MRI对肩袖损伤诊断的准确性和关节镜检查肩袖损伤的适应证。方法回顾性分析2007年7月至2010年12月北京大学人民医院创伤骨科行关节镜检查或治疗患者的59例肩部疾病患者，将MRI表现与关节镜检查所见进行对照分析。结果59例患者中，术前MRI检查明确诊断肩袖损伤36例；经关节镜检查证实肩袖撕裂35例，未见明显撕裂者1例。术前MRI检查未发现肩袖撕裂而关节镜下见撕裂7例，MRI检查与关节镜下均未见肩袖撕裂者16例。MRI对肩袖损伤诊断的敏感性为88.3%，特异性为94.1%，阳性预测值97.2%，阴性预测值69.6%，准确性86.4%。结论MRI是诊断肩袖损伤的有效辅助检查手段，但仍存在一定程度的漏诊情况；关节镜检查是诊断肩袖损伤最为可靠的辅助检查手段。

【关键词】 肩关节； 肩袖； 关节镜

【Abstract】BackgroundRotator cuff, a sleeve-like structure composed of supraspinatus, infraspinatus muscle, teres minor and subscapularis, is the major anatomical structure to maintain shoulder stability. Rotator cuff pathologies are frequently encountered in patients with pain at the shoulder. The rotator cuff can be visualized with different imaging techniques such as ultrasonography (US), arthrography, arthroscopy, computed tomography (CT) and magnetic resonance imaging (MRI). MRI had quickly become the favored method for preoperative diagnosis of the rotator cuff injury, with high soft tissue resolution ratio, sensitivity and accuracy. It is clinically significant to correctly understand the MRI manifestation of patients with the painful shoulder. We retrospectively analyzed the MRI examination and arthroscopy findings of 59 rotator cuff injuries treated in one hospital.Methods(1)Subjects：From July 2007 to December 2010, a total of 59 patients (25 males and 34 females, aged from 24 to 83 years old, mean age 54.33 years), who underwent arthroscopic surgery for their shoulder joint diseases, were selected. All the patients had shouder MRI examination before operation, we compared their preoperative MRI results with surgical findings.(2)Arthroscopic surgery：All arthroscopic surgical procedures were performed by experienced directors or deputy directors of physicians to obtain an accurate diagnosis of the rotator cuff injury. All patients were treated by Stryker (Stryker) arthroscopic systems for their diagnosis and treatment. Diagnosis was based on the surgical records or video records.(3)Magnetic resonance imaging：Multi-planar MR imaging of the shoulder was performed using coronal oblique, sagittal oblique and axial sequences. All MRIs were reported by a radiologist with special trained in musculoskeletal imaging. (4)Diagnosis of rotator cuff injury：Based on the lannotti classification criterion, according to their pathological changes, rotator cuff injuries can be classified as ① Tendinitis:increased tendon signal intensity, no morphological changes, and intact shoulder-deltoid bursa fat layer. ②Partial-thickness tear:the increased limitations of signal intensity at the tendon, morphological changes accompanied by the discontinuity of the shoulder-deltoid bursa fat layer. ③ Full thickness tear:the significantly increased tendon signal intensity, obvious morphological abnormalities such as discontinuity of the tendon, tendon-muscle belly retraction or obvious muscle atrophy, ie the increased signal intensity of the muscles, the discontinuity or disappearance of the acromion-the deltoid bursa fat layer.ResultsThirty-six out of 59 cases were diagnosed as the rotator cuff injury by MRI before operation,35 of which had been confirmed with tendinitis, partial-thickness tear or full thickness tear by arthroscopy during operation. One rotator cuff injury diagnosed before operation was proved to be intact arthroscopically. Seven cases with negative findings under MRI examination had been found to be rotator cuff injuries by arthroscopy. 16 cases (including fractures, shoulder instability or Bankart injury) of them presented intact in both MRI examination and arthroscopy operation. The sensitivity level of MRI examination for the rotator cuff injuries was 83.3%. The specificity level of MRI examination was 94.1%.The accuracy was 86.4%.The degree of positive prediction was 97.2%, and that of negative prediction was 69.6%. These rotator cuff injuries included 3 cases of tendinitis,13 cases of partial-thickness tear (10 of bursa side and 3 of articular side) and 22 cases of full-thickness tear.DiscussionPatients with rotator cuff injury are frequently encountered. As a hub of upper limb activities, rotator cuff determines the range of the shoulder activitivy and space accuracy. The rotator cuff muscles are main strength source of the shoulder, which play a vital role in the shoulder function. Therefore, rotator cuff injuries at the shoulder would produce different degrees of dysfunction and painfulness, and seriously affect the patient′s quality of life and activities of daily living.Firstly, we need to define that the rotator cuff injury is a partial-thickness tear or a full-thickness tear. Ellman divided the partial-thickness rotator cuff tears into three categories:synovial side partial-thickness tear,intra-tendon partial-thickness tear and articular side partial-thickness tear. Each category is divided into three degrees according to the depth of tear:degree Ⅰ (<3 mm),degree Ⅱ (3-6 mm),degrees Ⅲ (>6 mm), or more than 50% of the full-thickness at the tendon. Full-thickness tear classification is generally based on the size of tear:small tear (<1 cm), medium tear (1-3 cm), large tear (3-5 cm) and a massive tear (>5 cm).The imaging examination on the shoulder is indispensable in the diagnosis and classification of rotator cuff injuries, in addition to their detailed medical history and physical examination. The non-invasive and non-radioactive MRI, with excellent anatomy repeatability and organizational control comparability, can provide multi-angle, multi-plane and multi-level scan imaging, presenting a variety of normal and abnormal tissue structure imaging, which seems to be very important for the diagnose of shoulder diseases. In our study, the sensitivity level of MRI in diagnosis of the rotator cuff injury is 83.3%. Seven cases which were negatively diagnosed in MRI examination had been proved to be rotator cuff injuries by arthroscopy.Using arthroscopy, we can observe the rotator cuff directly to identify the scope, size, and shape of tears. And the shoulder joint synovitis, supraspinatus tendon degeneration and partial tears of the biceps tendon and other pathological changes can be also determined by arthroscopy, which can′t be comparable with other imaging techniques. Therefore, it is necessary to use arthroscopy for the patients who have long-term shoulder pain, functional limitation, long-term conservative treatment fails and other tests difficult to diagnose. Arthroscopy can provide not only the confirmation of the diagnosis, but also the treatment such as debridement of the shoulder joint synovial tissue and calcification of supraspinatus tendon and suture of the teared rotator cuff.ConclusionsAccording to our research and literature, generally speaking, MRI examination plays an important role for the diagnosis of rotator cuff injuries, which can provide the accurate determination of the extent, size and scope of rotator cuff injuries, as well as the signs associated. MRI can facilitate the development of treatment programs for the rotator cuff injuries, and eventually help patients to get timely and correct treatment.

【Keywords】 Shoulder; Rotator cuff; Arthroscopy

肩袖是由冈上肌、冈下肌、小圆肌及肩胛下肌的肌腱构成的包裹肱骨头的袖套样结构，是维持肩关节稳定的主要解剖结构。肩袖损伤是临床较为常见的引起肩关节疼痛的疾病，多为撕裂伤，大部分需行手术治疗，术前明确诊断对手术适应证及手术方案的制定都有重要意义。用于肩部影像学诊断方法有X线片、肩关节造影、肩关节CT及MRI。MRI以其对软组织的高分辨率、对损伤的高敏感性和特异性等特点已成为肩关节检查的首先考虑的影像学检查[1-3]。对有临床症状患者的MRI表现的正确理解无疑对肩关节镜诊疗有重要意义和价值，我们对北京大学人民医院创伤骨科59例肩关节镜检查患者的MRI资料进行回顾分析，旨在探讨MRI与肩关节镜诊断的准确性。

图1 冈上肌腱全层撕裂MRI和关节镜检查图像。A、B图示全层撕裂MRI表现；C图示全层撕裂关节镜下表现

材料和方法

一、一般资料

收集2007年7月至2010年12月59例因肩关节疾病而行肩关节镜检查或治疗患者的MRI和手术资料。其中男性25例，女性34例；年龄24～83岁，平均56岁。患者均因肩关节疼痛就诊，并入院行关节镜检查或治疗。经关节镜检查证实，肩袖损伤42例，其他肩部疾病17例。对59例肩关节的MRI表现和关节镜手术记录资料与影像进行对照分析。

二、关节镜诊疗技术

所有病例均使用史赛克(Stryker)关节镜系统进行诊疗。关节镜手术操作由经验丰富的主任医师或副主任医师进行，以获得肩袖撕裂的准确诊断。手术情况以手术记录及影像记录为准。

三、MRI技术及扫描位置

采用GE公司四肢关节专用扫描系统，常规取横轴位、斜冠状位、斜矢状位。

四、肩袖损伤的诊断

参考Lannotti等[4]分类方法，根据病理改变特征分类。(1)肌腱炎：肌腱信号强度均匀性增加，但无形态学改变，肩峰-三角肌下滑囊脂肪层完整；(2)不全断裂：肌腱信号强度局限性增加，形态也发生改变，并伴有肩峰-三角肌下滑囊脂肪层连续性中断；(3)完全断裂：肌腱信号强度明显增加，形态明显异常，如肌腱连续性中断、肌腱-肌腹连接处回缩或明显的肌肉萎缩，即肌肉的信号强度增高。肩峰-三角肌下滑囊脂肪层连续性中断或消失。

结 果

59例患者中，MRI检查明确诊断肩袖损伤36例；经关节镜检查证实肩袖损伤(包括肌腱炎、部分撕裂和全层撕裂)35例，肩袖组织完整1例。MRI检查未证实肩袖撕裂而关节镜下见撕裂7例，其他肩关节疾病(骨折、肩关节不稳定、Bankart损伤)经MRI检查与关节镜检查证实无肩袖损伤17例。MRI诊断肩袖损伤的敏感度为83.3%，特异度为94.1%，准确性为86.4%，阳性预测值97.2%，阴性预测值69.6%。经关节镜检查证实肩袖损伤者中，肌腱炎7例，部分肩袖撕裂13例，其中滑囊侧10例，关节侧3例。全层撕裂(图1)22例。

讨 论

肩袖损伤是肩关节外科的常见病。作为上肢的活动枢纽，肩关节决定了整个上肢的活动范围和活动的空间精确度。而肩袖肌群作为肩关节空间位置精确控制的主要动力因素之一，对肩关节的功能发挥起着至关重要的作用。因此肩袖损伤会使肩关节产生不同程度的功能障碍，并伴有疼痛，严重影响患者的日常生活和生活质量。

我们首先需要明确的是肩袖撕裂是部分撕裂还是全层撕裂。Ellman等[4]将肩袖部分撕裂分三类，即滑囊侧部分撕裂、肌腱间部分撕裂和关节侧部分撕裂。每一类根据撕裂深度分为三度：Ⅰ度，<3 mm；Ⅱ度，3～6 mm；Ⅲ度，>6 mm或超过肌腱厚度50%。在全层断裂一般根据断裂的大小分为：小断裂(<1 cm)、中断裂(1～3 cm)、大断裂(3～5 cm)和巨大断裂(>5 cm)[5]。

在肩袖损伤的诊断和鉴别诊断上除了详细询问病史和查体外，肩关节的影像学检查也是必不可少的诊断手段。其中MRI以其非侵入性、非放射性、解剖重复性和优良的组织对照可比性可进行多角度、多平面、多层次的扫描显像，能够同时提供多种组织结构的正常和异常的影像学图像，成为诊断肩部疾病非常重要的影像学检查之一[6]。MRI诊断肩袖损伤的敏感度为83.3%，在本组病例中经MRI检查未证实肩袖撕裂而关节镜下可见肩袖撕裂有7例患者。关节镜可清楚的直接观察到冈上肌腱滑囊侧和关节侧肩袖浅层磨损及全层损伤情况，了解肩袖断裂的范围、大小和形态；显示肩关节内滑膜炎、冈上肌腱退变和肱二头肌腱部分断裂等病理改变，其效果是影像学检查无法比拟的。因此，对肩关节疼痛、功能受限、长期保守治疗无效、其他检查方法难以确诊患者，采用关节镜检查十分必要。关节镜不仅能明确诊断，同时也可以进行镜下手术治疗，如肩关节滑膜组织增生、钙化和冈上肌腱滑膜侧及关节侧肩袖浅层磨损的清理、缝合修补等[7]。

综上所述，MRI检查对肩袖损伤的诊断价值较高，可以较准确地判断肩袖损伤程度、大小、范围及伴发的合并征象，为临床制定治疗方案提供帮助，最终使患者得到及时正确的治疗。

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