The shoulder is a highly mobile joint in which stability is maintained by a combination of osseous, capsulolabral, ligamentous, and musculotendinous structures. The rotator cuff is composed of the supraspinatus, infraspinatus, subscapularis, and teres minor tendons. These structures act as a functional unit to centre the humeral head within the glenoid during shoulder movement. Pathology of the rotator cuff is a frequent cause of shoulder pain and may range from tendinopathy and partial-thickness tearing to full-thickness tendon disruption and associated bursopathy.[1,2] Accurate characterization of rotator cuff disease is important because imaging findings influence clinical management, the need for conservative treatment, injection therapy, surgical referral, and operative planning. Conventional radiography has a limited role in direct tendon assessment, whereas USG and MRI provide substantially better soft-tissue characterization. MRI can demonstrate tendon integrity, tear morphology and extent, muscle atrophy, fatty change, and associated labral, capsular, biceps, and osseous abnormalities.[3] USG has several practical advantages. It is inexpensive, rapid, does not use ionizing radiation, permits dynamic examination, and can be performed in patients who cannot undergo MRI. High-resolution USG can demonstrate tendon discontinuity, focal hypoechoic defects, tendon retraction, bursal abnormalities, and calcific deposits. Earlier studies and systematic reviews have shown that USG has good diagnostic performance for full-thickness tears, although performance for partial-thickness tears is generally lower and is influenced by operator experience.[4–7] MRI is frequently used when a detailed assessment of the shoulder is required. It has excellent soft-tissue contrast and provides information beyond the rotator cuff itself. MRI may be particularly useful when USG findings are indeterminate, when a partial-thickness tear is suspected, or when there is concern for associated labral, capsular, muscle, or intra-articular pathology.[3,8] The Society of Radiologists in Ultrasound has emphasized that imaging should be selected according to the clinical scenario and that high-quality shoulder USG can be an important component of the diagnostic pathway for suspected rotator cuff disease.[8] Contemporary systematic reviews likewise indicate that USG and MRI can have comparable diagnostic performance for many rotator cuff tears, especially when USG is performed by experienced operators, although partial-thickness tears remain a recognized challenge.[6,9] The present prospective study was undertaken to describe the pattern of rotator cuff pathology in a tertiary-care setting and to evaluate the performance of USG compared with MRI in the assessment of rotator cuff abnormalities. Aim and Objectives Primary aim: To evaluate the spectrum of rotator cuff pathology and compare the diagnostic findings of USG with MRI in patients with clinically suspected rotator cuff disease. • To determine the frequency and distribution of pathology involving the supraspinatus, subscapularis, infraspinatus, and teres minor tendons. • To compare USG and MRI findings for tendinosis and partial- and full-thickness tendon tears. • To assess associated findings including joint effusion, biceps tendon sheath fluid, subacromial-subdeltoid bursal effusion, acromial morphology, and acromioclavicular joint degenerative changes.

This was a prospective observational study conducted in the Department of Orthopaedics at a tertiary-care healthcare centre in India. The study period was January 2024 to January 2025. Fifty patients with clinical suspicion of rotator cuff pathology who met the study eligibility criteria were included. Patient selection Patients were clinically assessed and referred for shoulder USG because of suspected rotator cuff pathology. MRI of the same shoulder was subsequently performed, and the findings of both imaging modalities were compared. Inclusion criteria • Patients with clinical suspicion of rotator cuff pathology. Exclusion criteria • Contraindication to MRI. • Shoulder fracture identified on radiography. • Patients unwilling or unable to cooperate with the study. • Previous shoulder surgery. • Previous history of recurrent shoulder dislocation. • Patients who did not undergo one of the two imaging examinations. Imaging assessment The principal structures assessed were the supraspinatus, infraspinatus, subscapularis, and teres minor tendons. The study also recorded joint effusion, peribicipital fluid, subacromial-subdeltoid bursal effusion, acromial morphology, and acromioclavicular joint degenerative changes. MRI was used as the comparator for the present diagnostic analysis. Because no operative or histopathological reference standard was reported in the supplied study, MRI should not be described as an absolute gold standard. Statistical analysis Categorical variables were summarized as frequencies and percentages. For tendon-level comparisons, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated from the explicit 2×2 counts reported in the Results section, with MRI treated as the comparator. Fisher's exact test was reported in the source document for selected tendon comparisons. A two-sided P value <0.05 was considered statistically significant in the original analysis. Because the source manuscript contains internally inconsistent counts for some tendon-level comparisons, the recalculated diagnostic metrics in this edited manuscript are restricted to the counts explicitly stated together in the Results section. The infraspinatus discrepancy is specifically flagged in the author-verification checklist.

A total of 50 patients fulfilling the stated eligibility criteria were included. The supplied study document did not provide a complete demographic table for age, sex, symptom duration, or laterality; therefore, these variables have not been inferred or added. MRI findings The supraspinatus was the most frequently abnormal tendon. MRI demonstrated abnormal supraspinatus findings in 43 patients (86%), comprising tendinosis in 19 (38%), full-thickness tear in 3 (6%), and partial-thickness tear in 21 (42%). The remaining 7 patients (14%) had a normal supraspinatus tendon. MRI demonstrated subscapularis abnormality in 20 patients (40%), comprising tendinosis in 14 (28%) and partial-thickness tear in 6 (12%); no full-thickness subscapularis tear was reported. The infraspinatus was abnormal in 6 patients (12%), including 5 partial-thickness tears (10%) and 1 case of tendinosis (2%). No teres minor pathology was identified. Tendon / MRI finding n % of 50 Supraspinatus tendinosis 19 38 Supraspinatus partial-thickness tear 21 42 Supraspinatus full-thickness tear 3 6 Supraspinatus normal 7 14 Subscapularis tendinosis 14 28 Subscapularis partial-thickness tear 6 12 Subscapularis full-thickness tear 0 0 Subscapularis normal 30 60 Infraspinatus tendinosis 1 2 Infraspinatus partial-thickness tear 5 10 Infraspinatus full-thickness tear 0 0 Infraspinatus normal 44 88 Teres minor pathology 0 0 USG findings and comparison with MRI USG detected abnormal supraspinatus findings in 40 patients (80%), including 18 with tendinosis (36%), 3 with full-thickness tears (6%), and 19 with partial-thickness tears (38%). All 7 patients with a normal supraspinatus on MRI were reported as normal on USG. For the subscapularis, USG detected 19 of the 20 abnormal tendons identified on MRI. USG reported 14 cases of tendinosis and 5 partial-thickness tears. One articular-surface partial tear reported on MRI was missed by USG. For the infraspinatus, the Results section of the source document reported 4 abnormal cases detected by USG (3 partial tears and 1 tendinosis) compared with 6 abnormal cases on MRI. All 44 MRI-normal infraspinatus tendons were reported as normal on USG. Tendon MRI abnormal, n USG abnormal, n MRI-normal, n USG false-negative count* Supraspinatus 43 40 7 3 Subscapularis 20 19 30 1 Infraspinatus 6 4 44 2 Teres minor 0 0 50 0 *Calculated from the explicit counts in the Results section. The later Discussion section of the source document states 5 rather than 4 USG-detected infraspinatus abnormalities; this discrepancy requires verification against the original dataset before journal submission. Diagnostic performance of USG When the explicit Results-section counts were reconstructed as 2×2 tables with MRI as the comparator, USG showed high specificity for all three tendons. For supraspinatus abnormality, sensitivity was 93.0%, specificity 100%, PPV 100%, NPV 70.0%, and accuracy 94.0%. For subscapularis abnormality, sensitivity was 95.0%, specificity 100%, PPV 100%, NPV 96.8%, and accuracy 98.0%. For infraspinatus abnormality, sensitivity was 66.7%, specificity 100%, PPV 100%, NPV 95.7%, and accuracy 96.0%. Tendon Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Supraspinatus 93.0 100.0 100.0 70.0 94.0 Subscapularis 95.0 100.0 100.0 96.8 98.0 Infraspinatus 66.7 100.0 100.0 95.7 96.0 Associated imaging findings Joint effusion was reported in 43 patients (86%); mild effusion was present in 27 patients (54%) and moderate effusion in 16 (32%). Peribicipital tendon sheath fluid was present in 17 patients (34%), while subacromial-subdeltoid bursal effusion was reported in 15 (30%). Type I acromion was the most common morphology (37 patients, 74%), followed by type II acromion (11 patients, 22%). Acromioclavicular joint degenerative changes were present in 20 patients (40%). The source study reported no statistically significant association between joint effusion or its degree and rotator cuff pathology.

The present prospective study evaluated 50 patients with clinically suspected rotator cuff disease and compared USG findings with MRI. The principal observation was that the supraspinatus was the most frequently abnormal tendon, followed by the subscapularis and infraspinatus. This distribution is consistent with the established clinical and imaging literature, in which supraspinatus pathology accounts for a substantial proportion of rotator cuff disease.[2,3] The high frequency of supraspinatus involvement in this cohort is clinically plausible because the tendon passes beneath the acromial arch and is exposed to repetitive mechanical loading. MRI identified abnormalities in 86% of supraspinatus tendons, including both tendinosis and partial- and full-thickness tears. USG detected 40 of the 43 MRI-abnormal supraspinatus tendons and all seven MRI-normal tendons. Based on the reported counts, this corresponded to 93.0% sensitivity and 100% specificity for detecting any supraspinatus abnormality. The performance of USG for supraspinatus pathology in the present study compares favourably with published evidence, although direct comparison should be interpreted cautiously because different studies use different reference standards and definitions of a positive test. Farooqi et al. reported high diagnostic accuracy for supraspinatus tears and found no statistically significant difference between USG and MRI in the studies that directly compared the two modalities.[6] Earlier work by Teefey et al. also demonstrated that experienced shoulder ultrasonography can provide accurate detection and measurement of rotator cuff tears.[7] The subscapularis findings are also noteworthy. MRI identified abnormality in 20 patients, while USG detected 19. The reconstructed sensitivity and specificity were 95.0% and 100%, respectively. Published studies demonstrate that subscapularis lesions can be more challenging than supraspinatus lesions, particularly when tears are small or partial. Studies comparing USG with arthroscopy have shown that sensitivity can be lower for small or partial subscapularis lesions than for larger supraspinatus tears, emphasizing the effect of lesion size, location, and operator experience.[10,11] The high performance observed in the present cohort may therefore reflect the local operator expertise and the case mix. The infraspinatus results should be interpreted more cautiously. The Results section reported six abnormal MRI findings and four detected on USG, producing a reconstructed sensitivity of 66.7%. This is lower than the corresponding sensitivity for supraspinatus and subscapularis. The source manuscript later reports five USG-detected infraspinatus abnormalities, creating an internal inconsistency that should be resolved from the original patient-level data before submission. This issue illustrates the importance of retaining a tendon-by-tendon diagnostic dataset rather than relying only on narrative summaries. A consistent finding across the literature is that full-thickness tears are generally easier to detect by USG than subtle partial-thickness tears. Ottenheijm et al. reported pooled USG sensitivity and specificity of 95% and 96%, respectively, for full-thickness tears, compared with 72% and 93% for partial-thickness tears.[5] A systematic review of 62 studies similarly found good diagnostic performance of USG for both partial- and full-thickness tears, with better performance for full-thickness tears.[4] These findings support the observation in the present study that USG was particularly useful for identifying complete tears but less reliable for subtle partial-thickness lesions. The difficulty in detecting partial-thickness tears is clinically important. Partial tears may involve the articular surface, bursal surface, or tendon substance, and their sonographic appearance can overlap with tendinosis or anisotropy. In the present study, one articular-surface partial tear of the subscapularis was missed on USG, and the source document describes missed partial-thickness abnormalities of the supraspinatus and infraspinatus. Ok et al. reported substantially lower sensitivity and accuracy of office-based USG for partial-thickness tears than for full-thickness tears, highlighting the influence of operator experience and lesion characteristics.[11] MRI has important advantages when the clinical question extends beyond the detection of a simple full-thickness tear. MRI can characterize the size and configuration of tears, muscle atrophy and fatty infiltration, tendon retraction, and associated labral, capsular, biceps, and osseous abnormalities.[3] Thus, USG and MRI should not be considered mutually exclusive techniques. Instead, the choice should be guided by the clinical question, availability, operator expertise, and the need for comprehensive preoperative assessment. The findings concerning joint effusion and bursal fluid deserve careful interpretation. In the present study, 86% of patients had joint effusion, but no statistically significant relationship between effusion and rotator cuff pathology was reported. This differs from some earlier studies. Hollister et al. found that isolated joint fluid had limited sensitivity and specificity for rotator cuff tears, whereas combined bursal and joint fluid was highly specific and had a high positive predictive value in their surgically evaluated population.[12] Other work has likewise shown that fluid findings should be interpreted in conjunction with direct assessment of the rotator cuff rather than used as an isolated diagnostic marker.[13] The study also found peribicipital fluid in 34% and subacromial-subdeltoid bursal fluid in 30% of patients. These findings may accompany rotator cuff and rotator interval pathology but are not specific enough to replace direct tendon evaluation. MRI can additionally demonstrate fluid in the subcoracoid space and associated anterior cuff or rotator interval abnormalities.[13,14] From a practical perspective, the advantages of USG include lower cost, rapid examination, dynamic assessment, absence of ionizing radiation, and greater accessibility. The Society of Radiologists in Ultrasound consensus statement supports a structured imaging pathway for painful shoulders and recognizes the value of high-quality USG in suspected rotator cuff disease.[8] A recent systematic review published in 2026 also concluded that USG can be a useful adjunct or first-line modality, particularly for full-thickness tears, while MRI remains important for partial tears, complex disease, and detailed preoperative planning.[15] The present study has several limitations. First, the sample size was small and the study was conducted at a single centre, which limits generalizability. Second, MRI rather than surgical or arthroscopic findings was used as the comparator; therefore, the reported measures describe agreement with MRI rather than definitive diagnostic accuracy against an independent reference standard. Third, the source document does not provide complete demographic and clinical variables, nor does it describe blinding, ultrasound equipment, transducer frequency, operator experience, MRI protocol, or interobserver agreement in sufficient detail for reproducibility. Fourth, several numerical inconsistencies are present in the source document, especially for infraspinatus findings and some tear-specific denominators. These discrepancies should be resolved against the original database before submission. Despite these limitations, the study provides clinically relevant prospective data from a tertiary-care setting and supports the role of USG as an accessible assessment tool for rotator cuff disease. The results are broadly consistent with the literature showing high performance for full-thickness tears and more variable performance for partial-thickness lesions.[4–6,15] CONCLUSION In this prospective single-center cohort of 50 patients with clinically suspected rotator cuff pathology, the supraspinatus was the most commonly affected tendon, followed by the subscapularis and infraspinatus. USG demonstrated high specificity and good sensitivity for detecting supraspinatus and subscapularis abnormalities when MRI was used as the comparator. The principal limitation of USG in the present study was the detection and characterization of partial-thickness abnormalities, particularly in less frequently affected tendons. USG may be considered a practical first-line imaging investigation for selected patients with suspected rotator cuff disease when performed by an experienced operator. MRI remains important when USG is inconclusive, when partial-thickness or complex pathology is suspected, and when comprehensive preoperative assessment is required. Larger prospective studies using arthroscopic or surgical findings as the reference standard would strengthen the evidence base.

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