Diagnostic evaluation of magnetic resonance imaging in shoulder pathologies.
Normal shoulder function is essential for day-to-day life. As the shoulder joint has a complex anatomy, imaging of the shoulder and its dysfunction is challenging for radiologist and orthopedic practitioners. Magnetic resonance imaging (MRI) played an important role as a non-invasive investigation due to its non-invasive nature, high degree of resolution, lack of contrast exposure and non-ionizing radiation, multiplanar capability, and excellent soft tissue resolution. [1,2] The most common indications for shoulder MRI are suspected shoulder instability, osteonecrosis, rotator cuff tear, infection, and neoplasm. Rotator cuff is being the most commonly affected, and subacromial impingement syndrome is the leading cause of rotator cuff injury. [3-5]
In this article, the most common indications for shoulder MRI are reviewed and discussed, but we focused primarily on the rotator cuff syndrome and shoulder instability. The present study was done to assess the prevalence of most common glenohumeral joint pathology and to study usefulness, advantages, and pitfalls of MRI in patients presenting with symptoms of glenohumeral joint pathologies.
MATERIALS AND METHODS
The main source of data for this prospective study was 50 patients referred for shoulder MRI to the Department of Radiodiagnosis, Geetanjali Medical College and Hospital, Udaipur, Rajasthan, during the period of September 2016-November 2017.
Method of Collection of Data
All patients diagnosed and suspicious of shoulder joint pathology were included in this study. They were advised and consulted by their physicians. Patients were explained about the procedure, and brief history of any prosthetic implant and illness was taken. Significant clinical findings of all patients were recorded. Previous investigations were reviewed (AP and axial radiograph of shoulder and sonography if done).
Duration of study
The study was conducted over a period of 14 months from September 2016 to November 2017.
MRI of the shoulder was performed using 1.5T Somatom, Siemens imaging system. The sequences used were--AXIAL T1 weighted (T1W), AXIAL T2W, AXIALPD, CORONALOBLIQUE STIR, CORONAL OBLIQUE PD, and SAGITTAL OBLIQUE T2. No medication/IV contrast was used in the study.
Adults between 18 and 70 years of age were included in the study.
Patients below 18 and above 70 years of age; patients with known history of malignancy and previous operative history of the shoulder; and those who have contraindications for MRI such as pacemaker, metallic implants, and claustrophobia were excluded from the study.
In our study, the incidence of shoulder joint pathologies was highest in the age group of 41-50 years which is 38%. Mean age of our study population is 46.6 years. 28 males (56%) and 22 females (44%) were affected in our study and male: female ratio was 1.27:1. Among 50 patients included in the study, the various pathologies detected on MRI are tabulated in Table 1. Rotator cuff disease was found in 88% of cases, making it the most common pathology of glenohumeral joint, for which MRI was done. MRI was done in an emergency for traumatic injuries for 46% of patients. For the rest of 66% of patients, there was a chronic course, for which MRI was advised. The least common group was infective (10%). The most common symptom, for which MRI is done, is shoulder pain. In around half of the patients, pain is associated with restriction of joint movements. In patients with recent traumatic injury and infective etiology, swelling and redness of the joint are found. Of 50 patients with glenohumeral pathology, 42 patients (84%) presented with a history of shoulder pain. 33 patients (66%) presented with a history of restriction of joint movements. 11 (22%) patients presented with a history of localized swelling or redness.
In our study, involvement of supraspinatus muscle or tendon was 74% in all the pathologies. Involvement of subscapularis and infraspinatus muscles does not show much difference [Figure 1]. Of the 42 patients diagnosed with supraspinatus tear, partial tear was seen in 34 patients (81%) and complete tear was seen in 8 (19%) patients [Figure 2]. In supraspinatus tendon tear, traumatic (n = 21) and non-traumatic (n = 21) etiologies comprise the same number of patients. Partial supraspinatus tear was more commonly seen with traumatic injuries.
In patients with single tendon involvement, supraspinatus tendon was the most common tendon involved. Involvement of other tendon along with supraspinatus tendon varies as per table, but it does not show much difference. In 10% of patients, all the three major rotator cuff muscles were involved [Table 2]. Osteoarthritis of acromioclavicular joint is a common occurrence in our study. Many of these patients (42%) had partial tear of supraspinatus tendon along with osteoarthritis [Table 3]. Joint effusion is a common association of glenohumeral pathologies. Possible etiologies are a direct injury to bicipital tendon insertion site or associated inflammation in the early phase of pathology. Subacromial-subdeltoid bursitis was seen in 44% of patients. It was more commonly related to early inflammatory changes [Table 4].
Different types of pathologies are presented in Figures 3-9.
MRI of the shoulder joint has achieved wide acceptance due to the sensitivity and specificity of MR in detection of rotator cuff pathologies and impingement syndrome. The negative likelihood ratio for a rotator cuff tear is 0.08 with MRI. [6-8] In our study, rotator cuff disease was the most common pathology of glenohumeral joint, for which MRI was done. Among all the analyzed shoulder MRI examinations, rotator cuff injury was the most common injury (diagnosed in 44 [88%] patients), which is concordant with a study by Tuite indicating that supraspinatus muscle tendon is damaged in 95% of rotator cuff pathologies.  Involvement of supraspinatus muscle was the same in traumatic and non-traumatic injuries. Associated involvement of subscapularis and infraspinatus muscles did not show much difference. MR features are 100% sensitive and 100% specific for combined full and partial thickness tears. 
According to Carrino
* Grade 0--Normal--uniform low signal intensity of tendon.
* Grade I--Increased signal intensity in tendon, more obvious on T1W image (T1WI) and proton images but not seen or less obvious on T2WI.
* Grade II--Tendinosis/tendinitis--Increased signal intensity on T2WI that does not involve inferior (articular) or superior (bursal) surface.
* Grade III--Degenerative--Increased signal intensity on T2WI in one or multiple areas but no changes to the criteria of partial tear.
* Grade IV--Partial tear--Increased signal intensity on T2WI that involves the inferior or superior surface of the tendon.
* Grade V--Full thickness tear with few spared fibers.
* Grade VI--Full thickness tear without tendon retraction.
* Grade VII--Full thickness tear with tendon retraction.
Sometimes, tear may not show hyperintensity in T2WI, so few secondary signs which may suggest tear are as follows:
* Fatty atrophy of muscle belly in the complete tear as hyperintensity on T1WI associated with loss of volume.
* Tendons may be completely nonvisualized due to retraction in the complete tear.
* Loss of peribursal or subdeltoid fat plane and fluid in subacromial-subdeltoid bursa.
* Joint effusion.
* Marrow signal changes and cyst formation in greater tuberosity on fat-suppressed T2WI with osseous changes such as osteophytosis and spur formation suggest cuff tendinopathy in advanced stages.
* Partial volume averaging with superior + lateral infraspinatus tendon.
* Vascular watershed area.
* Magic angle effect is the orientation of collagen fibers at 55[degrees] relative to main magnetic field.
* Hyperintense focus within rotator cuff on T2WI.
* Partial volume averaging with fluid in biceps tendon sheath/subscapularis bursa.
* Partial volume averaging with fat of peribursal fat.
* Motion artefacts: Respiration, vascular pulsation, and patient movement.
* Fatty atrophy of muscle.
Osteoarthritis of acromioclavicular joint was a common occurrence in our study (42%). Many of these patients had a partial tear of supraspinatus tendon along with osteoarthritis, which is concordant with other studies indicating it as one of the causes of rotator cuff injury. 
Findings seen in our study showed that traumatic injuries result in fractures (26%) and bone contusion (30%). Involvement of glenohumeral joint in infective etiology is much less common. Joint effusion is a common association of glenohumeral pathologies. Possible etiologies are direct injury to bicipital tendon insertion site or associated inflammation in the early phase of pathology. Subacromial-subdeltoid bursitis was seen in 44% of patients.
MRI proves to be a valuable tool in the evaluation of biceps tendon disorders, avascular necrosis, inflammatory processes, and tumors. 
Pitfalls in Diagnosis of Labral Tears [14-16]
In several trials, relatively low sensitivity and negative predictive value has been noticed which makes the diagnosis of labral lesions challenging. [17,18] MRI appearance of labrum is usually triangular. The configuration of the anterior labrum may vary considerably from one individual to another, and in the same person, labral shape changes with rotation of the humerus.
Some normal structures may be misinterpreted as labral tears. The hyaline articular cartilage of the glenoid extends under and undercuts the base of the labrum. At MRI, this produces a linear area of increased signal intensity that may resemble a tear. At the level of the subscapularis tendon, the middle glenohumeral ligament runs parallel to the anterior labrum and also shows low signal intensity. The space between the ligament and the labrum may mimic a tear along the outer border of the labrum, but its true nature is usually revealed when one follows the ligament along its normal course on sequential images.
The sublabral recess or foramen can mimic a labral tear. A collection parallel to the shape of the bony glenoid and extending medially is probably a normal structure, whereas a collection that turns in a lateral direction into the substance of the labrum is most likely a tear. The exact location of the fluid collection may also provide a hint because a normal recess or foramen should not extend posterior to the biceps origin, whereas a labral tear often does.
MRI may reveal occult fractures, which appear as a line of abnormal signal intensity extending through cancellous bone to reach a cortical surface. Rotator cuff tears associated with greater tuberosity fractures can also be assessed. MRI can also demonstrate soft tissue injuries such as the glenoid labrum and cartilage disruption. Injuries to the muscles, such as the pectoralis major, can also be demonstrated. MR findings on proton-density-weighted images include hyperintense edema in the clavicle, sternum, humerus, or ribs, reflecting injury to the attachment sites of the pectoralis major tendons. Edema and hemorrhage in the muscle, myotendinous junction, perifascial zone, or subcutaneous fat can also be demonstrated. The degree of tendon retraction can also be assessed. In addition, both computed tomography and MRI are important to demonstrate incidental findings associated with trauma, such as a hemothorax or pneumothorax. [19,20]
MRI has become the gold standard for diagnostic imaging of the soft tissue injury of the shoulder. This is mainly because of its non-invasive nature, high degree of resolution, lack of contrast exposure, non-ionizing radiation, and the ability to evaluate and analyze multiple potential pathologic processes.  As the shoulder joint has a complex anatomy, imaging of the shoulder and its dysfunctions is one of the most challenging regions for radiologists and orthopedicians. Technical development in MRI and clinical advances in shoulder therapy ensures that MRI will continue to play an important role in the diagnostic and therapeutic management of patients with shoulder disease.
[1.] de Jesus JO, Parker L, Frangos AJ, Nazarian LN. Accuracy of MRI, MR arthrography, and ultrasound in the diagnosis of rotator cuff tears: A meta-analysis. AJR Am J Roentgenol 2009;192:1701-7.
[2.] Murray PJ, Shaffer BS. Clinical update: MR imaging of the shoulder. Sports Med Arthrosc 2009;7:40-8.
[3.] Van der Windt DA, Koes BW, De Jong BA, Bouter LM. Shoulder disorders in general practice: Incidence, patient characteristics, and management. Ann Rheum Dis 1995;54:959-64.
[4.] Blanchard TK, Bearcroft PW, Constant CR, Grifn DR, Dixon AK. Diagnostic and therapeutic impact of MRI and arthrography in the investigation of full-thickness rotator cuff tears. Eur Radiol 1999;9:638-42.
[5.] Sheehan SE, Gaviola G, Gordon R, Sacks A, Shi LL, Smith SE, et al. Traumatic shoulder injuries: A force mechanism analysis-glenohumeral dislocation and instability. AJR Am J Roentgenol 2013;201:378-93.
[6.] Torstensen ET, Hollinshead RM. Comparison of magnetic resonance imaging and arthroscopy in the evaluation of shoulder pathology. J Shoulder Elbow Surg 1999;8:42-5.
[7.] Burk DL Jr., Karasick D, Kurtz AB, Mitchell DG, Rifkin MD, Miller CL, et al. Rotator cuff tears: Prospective comparison of MR imaging with arthrography, sonography, and surgery. AJR Am J Roentgenol 1989;153:87-92.
[8.] Yeu K, Jiang CC, Shih TT. Correlation between MRI and operative findings of the rotator cuff tear. J Formos Med Assoc 1994;93:134-9.
[9.] Tuite MJ. Magnetic resonance imaging of rotator cuff disease and external impingement. Magn Reson Imaging Clin N Am 2012;20:187-200.
[10.] Needell SD, Zlatkin MB, Sher JS, Murphy BJ, Uribe JW. MR imaging of the rotator cuff: Peritendinous and bone abnormalities in an asymptomatic population. AJR Am J Roentgenol 1996;166:863-7.
[11.] Zlatkin MB. Rotator Cuff Disease. MRI of the Shoulder. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003. p. 117.
[12.] Giaroli EL, Major NM, Higgins LD. Coracohumeral interval imaging insubcoracoid impingement syndrome on MRI. Am J Roentgenol 2006;186:242-6.
[13.] Link TM, Waldt S, Stawy WK. In: Rummeny EJ, Reimer P, Heindel W, editors. Obrazowanie Ciala Metodq Rezonansu Magnetycznego. Warszawa: Medmedia; 2010. p. 470-542.
[14.] McCauley TR, Pope CF, Jokl P. Normal and abnormal glenoid labrum: Assessment with multiplanar gradient-echo MR imaging. Radiology 1992;183:35-7.
[15.] McNiesh LM, Callaghan JJ. CT arthrography of the shoulder: Variations of the glenoid labrum. AJR Am J Roentgenol 1987;149:963-6.
[16.] Seeger LL, Gold RH, Bassett LW, Ellman H. Shoulder impingement syndrome: MR findings in 53 shoulders. AJR Am J Roentgenol 1988;150:343-7.
[17.] Iannotti JP, Zlatkin MB, Esterhai JL, Kressel HY, Dalinka MK, Spindler KP. Magnetic resonance imaging of the shoulder. Sensitivity, specificity, and predictive value. J Bone Joint Surg 1991;73:17-29.
[18.] Green MR, Christensen KP. Magnetic resonance imaging of the glenoid labrum in anterior shoulder instability. Am J Sports Med 1994;22:493-8.
[19.] Hodler J, Kursunoglu-Brahme S, Snyder SJ, Cervilla V, Karzel RP, Schweitzer ME, et al. Rotator cuff disease: Assessment with MR arthrography versus standard MR imaging in 36 patients with arthroscopic confirmation. Radiology 1992;182:431-6.
[20.] Kilcoyne RF, Shuman WP, Matsen FA 3rd, Morris M, Rockwood CA. The neer classification of displaced proximal humeral fractures: Spectrum of findings on plain radiographs and CT scans. AJR Am J Roentgenol 1990;154:1029-33.
Hari Ram, Ravinder Kumar
Department of Radiodiagnosis, Geetanjali Medical College and Hospital, Geetanjali University, Udaipur, Rajasthan, India
Correspondence to: Ravinder Kumar, E-mail: firstname.lastname@example.org
Received: April 25, 2018; Accepted: May 13, 2018
Caption: Figure 3: Tear of supraspinatus tendon
Caption: Figure 4: Tear of infraspinatus, supraspinatus and subscapularis tendons, displaced fracture of humeral neck with posterior dislocation of humeral head, osteoartritis of acromio-clavicular joint
Caption: Figure 5: Complete tear of suprispinatus tendon, partial tear of teres minor and subscapularis tendon, Bankart's lesion
Caption: Figure 6: Subarticular edema in antero-mferior glenoid with labral tear--Bankart's lesion
Caption: Figure 7: Complete supraspinatus tear, partial infraspinatus tear, osteoarthritic changes in acromioclavicular joint
Caption: Figure 8: Partial supraspinatus tear on interstitial and bursal attachment?
Caption: Figure 9: Osteomyelitis changes
Table 1: Frequency of shoulder pathologies Pathologies of shoulder joint Number of patients (%) Rotator cuff disease 44 (88) Glenohumeral joint instability 11 (22) Labral injuries 8 (16) Traumatic injuries 23 (46) Degenerative osteoarthritis 14 (28) Infective etiology 5 (10) Table 2: Involvement of multiple tendons Tendon involved Number of patients (%) Supraspinatus 24 (48) Supraspinatus+subscapularis 7 (14) Supraspinatus+infraspinatus 5 (10) Supraspinatus+teres minor 1 (2) Supraspinatus+infraspinatus+subscapularis 5 (10) Table 3: Bony changes (n=23) Bony changes Number of patients (%) Fracture 6 (26) Osteoarthritis of 11 (42) acromioclavicular joint Osteoarthritis of 3 (13) glenohumeral joint Bone contusion 7 (30) Defect on posterolateral 3 (13) aspect of humerus Osteomyelitis 5 (21) Bony cyst 1 (4) Table 4: Joint effusion Joint effusion Number of patients (%) In joint cavity 14 (28) In subacromian subdeltoid bursa 22 (44) In bicipital grove 22 (44) In all above three compartments 3 (6) Figure 1: Involvement of muscles Muscles involved ibscapularis 18 Supraspinatus 74 Infraspinatus 22 Teres minor 2 Note: Table made from bar graph. Figure 2: Involvement of supraspinatus tendon Partial tear 81.0% Complete tear 19.0% Note: Table made from pie chart.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Research Article|
|Author:||Ram, Hari; Kumar, Ravinder|
|Publication:||International Journal of Medical Science and Public Health|
|Article Type:||Clinical report|
|Date:||Sep 1, 2018|
|Previous Article:||Awareness of diabetic retinopathy and barriers for eye screening among adults with type 2 diabetes mellitus attending tertiary care teaching...|
|Next Article:||A study on dietary intake among school going adolescent girls in rural and urban area of Jamnagar District, Gujarat.|