Rotator Cuff Pathology Workup

Updated: Nov 30, 2015
  • Author: R H Bilal, MBBS, MRCS; Chief Editor: S Ashfaq Hasan, MD  more...
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Workup

Approach Considerations

A wide variety of imaging examinations are offered to image the rotator cuff, including plain radiography, arthrography, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography. Each of them has advantages and limitations. Bone scintigraphy is not used routinely in rotator cuff disease imaging.

To prescribe the most useful examination, one must start with a good clinical history and physical examination. Imaging should be used to confirm the anomaly and to describe its extension and the associated findings. The following sections briefly explain the indications, the technique, and the findings for each modality available to image the rotator cuff in radiology. [25, 26]

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Plain Radiography

Plain films are not very specific or sensitive for rotator cuff disease, but they remain the first examination to perform. Radiographs are used for gross evaluation of the mineralization of the bone, the alignment, posttraumatic changes, the normal variant of the acromion shape, the presence of degenerative changes, and the presence of fine soft tissue calcifications that could be missed with by other modalities. This is the most useful test in trauma situations or to assess chronic complete tears. In the last stage of complete chronic rotator cuff tear, it could be the only imaging modality needed to confirm the diagnosis (see the image below).

In this patient's shoulder radiography, the humera In this patient's shoulder radiography, the humeral head no longer matches up with the glenoid because the rotator cuff is torn and the strong deltoid muscle is pulling the head superiorly toward the acromion. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

Plain films are acquired routinely in three planes (ie, neutral, internal, external rotation).

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Arthrography

The main indication for arthrography is to identify complete rotator cuff tears and intra-articular infiltration of the corticoid. As a diagnostic tool, it is combined generally with CT arthrography. [27]

Arthrography is performed by injecting iodine contrast medium, air, or both into the glenohumeral joint. Either 8-12 mL of contrast or 3-4 mL of contrast with 10-12 mL of air is injected to distend the joint capsule. If air and contrast are injected, the term double-contrast study is used. Then, plain films are taken in different positions, such as external rotation, internal rotation, and subacromial views, before and after motions. (See the image below.)

This image depicts the channel between the articul This image depicts the channel between the articular capsule and the subacromial-subdeltoid bursa in a complete rotator cuff tear. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

In the presence of a complete tear, the contrast floods from the glenohumeral joint into the subacromial-subdeltoid bursa (see the images below).

Even if the channel cannot be always identified, t Even if the channel cannot be always identified, the presence of contrast medium in the subdeltoid-subacromial bursa signals the presence of a complete rotator cuff tear. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.
CT-arthrography of the shoulder in the axial plane CT-arthrography of the shoulder in the axial plane. Note the presence of air and contrast in the subacromial-subdeltoid bursa. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

With a partial tear, the contrast is seen as a line or a small filled cavity within the tendon but without contrast in the subacromial-subdeltoid bursa. This finding is more difficult to demonstrate in a complete tear. Intratendon tears and tears on the superior aspect of the tendon (bursal side) are not visualized with this technique. Arthrography can also provide some information about the long portion of the biceps tendon, loose bodies, and synovial disorders, such as inflammatory synovitis, osteochondromatosis, or villonodular pigmented synovitis.

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CT Arthrography

CT arthrography, though very accurate (100% sensitivity, 100% specificity) in depicting complete rotator cuff tears, is limited in the evaluation of tendinitis and partial tears, for which its sensitivity drops to 17-43%. On the other hand, this test yields more information than arthrography regarding the joint itself and the soft tissues around it. The ability to evaluate the labrum, the glenohumeral ligaments, the long head of the biceps tendon, and the bony structures, as well as the presence of loose bodies, makes this a useful study.

CT arthrography is performed exactly like double-contrast (air and iodine contrast) arthrography but is followed by tomodensitometry imaging (CT scanning). For this examination, the shoulder is imaged in the axial plan in internal and external rotation. Thin slices as small as 2-3 mm are acquired throughout the entire joint. With new CT technology, it has become easy to reformat images in multiple planes.

The semiologic signs of rotator cuff tears are essentially the same as seen with conventional arthrography. The presence of contrast in the subacromial-subdeltoid space confirms the diagnosis of complete rotator cuff tears (see the images below). The contrast can also facilitate determination of the size and location of the tear to help the surgeon plan the surgery. Degenerative findings such as osteophytes, geodes, sclerosis, and articular space narrowing are also well depicted.

CT-arthrography of the shoulder in the axial plane CT-arthrography of the shoulder in the axial plane. Note the presence of air and contrast in the subacromial-subdeltoid bursa. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.
CT-arthrography of the shoulder in the axial plane CT-arthrography of the shoulder in the axial plane. Note the presence of air and contrast in the subacromial-subdeltoid bursa. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

In addition to conventional arthrography, this technique can identify labral and glenohumeral ligament tears. The presence of contrast between the labrum and the articular space indicates the presence of a tear. The axial views also permit a good visualization of the long head of the biceps tendon in its groove. Therefore, subluxation of this tendon, or rupture, can also be diagnosed. Finally, the shape of the acromion can be evaluated on the oblique sagittal reformatted study, which requires a special acquisition.

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MRI and MRI Arthrography

MRI is the state-of-the-art diagnostic tool for a full evaluation of the shoulder. It allows fine evaluation of the bone marrow, tendons, muscles, ligaments, capsules, bursae, and labrum. It combines the advantage of visualization of the bony structures and of all the soft tissues about the shoulder and in any plane desirable.

With this imaging modality, the full continuum of rotator cuff disease, from simple tendinosis to complete tears, can be diagnosed. MRI is much more powerful than the previous modalities when used to identify partial tears, and it also can identify intratendon tears or tears on the bursal aspect of the tendon. As with CT and plain radiography, the bone structures resulting or contributing to the impingement syndrome can be evaluated. [27, 28, 29]

MRI can also yield information about retraction of the muscle, atrophy, bursitis, and bone marrow abnormalities (eg, edema, contusion), which all are associated findings of rotator cuff disease.

MRI is somewhat limited in the evaluation of the labrum and glenohumeral ligaments. MRI arthrography is the study of choice for the evaluation of labrum and glenohumeral ligaments.

Because this technique takes advantage of the properties of hydrogen protons submitted to a magnetic field and radiofrequency waves, the patient is not subjected to radiation exposure. Multiple sequences are available to highlight different substances, such as water, fat, blood, or solid structures. Mainly spin-echo T1, spin-echo T2, and gradient-echo sequences, in axial, sagittal, and coronal oblique plans, are acquired in different combinations. Inversion recovery, fat saturation, and injection of gadolinium (intravenous or intra-articular) can be added if necessary.

MRI shows great detail of the anatomy in multiple plans. MRI also allows better visualization of the nature of a structure or an anomaly (ie, according to its intrinsic property). Therefore, the examiner should know some characteristics of the MRI signals for the most common structures.

Fat, methemoglobin, melamine, gadolinium, and some forms of calcium all are hyperintense in T1-weighted images. On the contrary, water appears at low signal intensity. In T2-weighted images or in gradient echo, the liquids are hyperintense, as are most lesions, meaning that edema, inflammatory processes, tumors, tendinitis, and tendon tears are hyperintense in T2-weighted images and hypointense in T1-weighted images. Therefore, the presence of fluid in a bursa or articular joint is hyperintense in T2 or gradient echo and indicates inflammatory or posttraumatic fluid. A full-thickness tear of the tendon is demonstrated by a hypersignal intensity in T2 that extends throughout the tendon (see the image below).

Full-thickness tear of the supraspinatus as seen a Full-thickness tear of the supraspinatus as seen as a hyperintensity line through the full thickness of the tendon in a flash 2-dimensional MRI sequence in coronal oblique plane. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

Tendinitis is recognized as a gray signal in the tendon. Finally, calcification and cortical bone appear hypointense in all sequences (see the image below).

Calcifications are seen as hypointense foci in fla Calcifications are seen as hypointense foci in flash 2-dimensional images. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

MRI arthrography is the gold standard as an imaging modality for diagnosis of a rotator cuff tear. It follows the same principle as CT arthrography. This modality can help identify labral tears (see image below) and glenohumeral tears.

MRI arthrography can help to identify labral tears MRI arthrography can help to identify labral tears, as seen in this image. The contrast medium penetrates between the labrum and the articular surface. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

The size and morphologic features of rotator cuff tears may influence treatment selection and affect final outcomes. MRI arthrography allows observation of these features and other intra-articular structures.

In one series, Toyoda et al [30] compared MRI with MRI arthrography. To assess the utility of MRI in assessing size and morphologic features, the authors did a retrospective analysis of 41 shoulders in 37 consecutive surgically treated patients (mean age, 63.2 years) who had MRI followed by MRI arthrography. The maximum rotator cuff defect size in the anteroposterior direction defined transverse size, and the maximum rotator cuff defect size in the mediolateral direction defined longitudinal size. Sensitivity for detecting full-thickness rotator cuff tears by MRI was 90.2%, compared with 100% for MRI arthrography. [30]

MRI arthrography also allowed morphologic classification of the torn tendon as blunt end, tapering end, indistinct end, horizontal tear, and global tear. There was good agreement in classifying torn edges: the imaging findings agreed with findings at surgery. MRI arthrography was more accurate in evaluating both rotator cuff tear size and morphologic features than MRI. [30]

With the aid of fat-suppressed imaging, full thickness and partial cuff tears can be identified with 100% sensitivity and specificity. Fat-suppressed images also showed intratendinous contrast material imbibition in three torn cuffs with frayed, friable tendon margins. Fat suppression in MRI arthrography is valuable in the differentiation between partial and full-thickness cuff tears and in the detection of small partial tears of the inferior tendon surface.

De Jesus et al performed a meta-analysis study to compare the diagnostic accuracy of MRI, MR arthrography, and ultrasound in diagnosing rotator cuff tears. The literature showed that MR arthrography is the most sensitive and specific technique for diagnosing both full- and partial-thickness rotator cuff tears and that ultrasound and MRI are comparable in both sensitivity and specificity. Summary ROC (receiving operating characteristic) curves for MR arthrography, MRI, and ultrasound for all tears showed the area under the ROC curve is greatest for MR arthrography (0.935), followed by ultrasound (0.889) and then MRI (0.878); however, pairwise comparisons of these curves showed no significant differences between MRI and ultrasound (P >.05). [26]

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Ultrasonography

Ultrasonography uses the same principles as radar. The images are created using a high-resolution transducer that first sends a sound signal and then receives the echo produced when the sound hits the different structures at different depths. [28, 31, 32]

The advantages of this technique reside in its low cost, high availability, and high resolution. Ultrasonography is a dynamic study for demonstrating impingement syndrome. The disadvantages are that it is time-consuming for the radiologist and is operator-dependent. Ultrasonography cannot study bone structures because sound does not penetrate bone very well.

With ultrasonography, the normal tendon is an echoic structure, whereas the cartilage and fluids are hypoechoic. All of the tendons, bony landmarks (eg, humerus, greater tuberosity), and intra-articular or intrabursal effusions are easily recognized. Tendinitis is diagnosed when the tendon loses its echogenicity and becomes diffusely hypoechoic. Calcifications appear as bright foci within the tendon, accompanied by a posterior shadowing, because the sound cannot pass through the calcium.

The main, and most sensitive, sign of a complete rotator cuff tear is an interruption in the tendon that fills with fluid, producing a hypoechogenic foci extending from the cartilage surface to the subdeltoid-subacromial bursa (see image below). The secondary signs include the uncovered cartilage (cartilage appears hyperechoic at the site of the tear), bursa herniation, loss of convexity of the tendon and bursa, and effusion within the glenohumeral articulation and the subacromial-subdeltoid bursa.

Ultrasound is another modality to demonstrate a co Ultrasound is another modality to demonstrate a complete rotator cuff tear, as seen here with a gap of more than 2 cm between both extremities of the torn tendon. Courtesy of Dr Thomas Murray, Orthopaedic Associates of Portland.

The diagnosis of a partial rotator cuff tear is made when the hypoechoic or bursal herniation does not cross the full width of the tendon. The use of ultrasound also allows the operator to demonstrate, in real time, the impingement of the supraspinatus tendon on the acromion when the arm is positioned in internal rotation and moved in abduction or flexion.

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