The human shoulder, with its intricate network of bones, muscles, tendons, and ligaments, stands as a marvel of biomechanical complexity. It enables a wide range of motion, facilitating everyday activities from lifting weight to executing precise athletic manoeuvres. However, this remarkable mobility also renders the shoulder vulnerable to a myriad of pathologies, often resulting in debilitating pain and functional impairment. Rotator cuff issues, notably rotator cuff tears,

frequently contribute to shoulder pain. Relying solely on clinical examination has limitations in determining the appropriate management approach for the underlying cause. Deciding between conservative treatment and surgery hinges on an accurate diagnosis and the severity of any rotator cuff tear ^{[1, 2]}.

Individuals experiencing shoulder pain or impairment may exhibit typical indicators and symptoms that enable precise clinical identification. Nonetheless, distinguishing between these conditions can sometimes pose challenges, prompting the utilization of diverse imaging methods for further assessment. These methods range from conventional plain radiographs to advanced magnetic resonance imaging (MRI) employing intra-articular contrast and phased array surface coils. Each imaging modality possesses distinct strengths and weaknesses in the assessment of shoulder pathology. High-resolution ultrasound (USG) and magnetic resonance imaging (MRI) are the INDISPENSABLE tools in the armamentarium of clinicians. High-resolution ultrasound (USG) and magnetic resonance imaging (MRI) are the preferred imaging methods for assessing suspected rotator cuff tears. Each modality has its advantages and disadvantages, with factors such as accuracy, availability, cost-effectiveness, and expertise influencing the choice of modality ^[3].

These imaging techniques offer distinct advantages in visualizing the anatomical structures of the shoulder, providing invaluable insights into the underlying pathology. Ultrasound, characterized by its real-time imaging capability and non-invasiveness, allows for dynamic evaluation of soft tissues, including tendons, muscles, and bursae ^[4]. Its portability and cost-effectiveness make it particularly advantageous for point-of-care assessment and guided interventions [5]. Conversely, magnetic resonance imaging offers unparalleled spatial resolution and tissue contrast, enabling detailed visualization of both osseous and soft tissue structures within the shoulder complex [6]. Furthermore, advanced MRI techniques, such as magnetic resonance arthrography and diffusion-weighted imaging, have expanded the diagnostic utility of MRI in delineating subtle pathology.

Previous studies have evaluated the accuracy of ultrasound or MRI individually in detecting rotator cuff tears, with only a few comparing the two methods. Shoulder ultrasonography offers advantages such as low cost, widespread availability and real-time imaging, although literature review indicates variability in its accuracy, particularly in distinguishing between complete and partial tears. MRI boasts multiplanar capability, providing detailed soft tissue information. It has demonstrated high sensitivity and specificity in evaluating rotator cuff tears [7].

Among the diagnostic modalities available for assessing shoulder conditions, ultrasound (US) and magnetic resonance imaging (MRI) have emerged as the most reliable and widely used tools, offering complementary strengths in evaluating soft tissue and structural pathologies. The aim of the present study was to assess the role of USG and MRI in painful shoulder joint.

The Descriptive correlational study was carried out in the Department of Radiodiagnosis, Maharishi Markandeshwar Institute of Medical Sciences and Research, Mullana, Ambala. 50 cases were included in the study.

INCLUSION CRITERIA

• All patients with painful shoulder
• Patients of both sexes

EXCLUSION CRITERIA

• Patients suffering from claustrophobia.
• Patients having any metallic implants/ foreign body.
• Patients refusing to consent.

METHOD

Patients meeting the inclusion criteria were subjected to undergo ultrasonography (Philips Affinity) and an MRI on 1.5 Tesla scanner (ACHIEVA Philips Medical Systems or MULTIVA Philips Medical Systems). This study was conducted for a period of 2 years from 2022-2024. Consent was obtained from each patient. The detailed history and general physical and systemic examination was done as mentioned in the proforma.

TECHNIQUE

USG: The patient had to sit on a stool with a short back support, which allowed patient stability and US access to all aspects of the shoulder. 10-15 MHz linear transducer ensures adequate penetration and resolution.

GENERAL CONSIDERATIONS

The patient has to sit on a stool with a short back support, which allows patient stability and US access to all aspects of the shoulder. The examiner can sit on a stool in front of the patient or stand behind the patient and should ideally be positioned so that his or her shoulder is higher than the patient's shoulder and the elbow should be close to the body rather than extending the arm toward the patient. The transducer should be held at its end, stabilizing the transducer by resting either the edge of the hand or the little finger on the patient, which reduces strain on the shoulder and allows fine motor control during USG scanning.

10-15 MAz linear array transducer ensures adequate penetration and resolution with minimal anisotropy. One of the important prerequisites is the tendon should be perpendicular to the sound beam. If the bone cortex under a tendon is clearly defined and hyper echoic, that indicates the sound beam is perpendicular to the overlying tendon minimizing anisotropy. Long head of biceps was assessed with the patientʻs hand placed on his or her leg. Subscapularis was assessed with the patients shoulder in external rotation. Supraspinatus and Infraspinatus were assessed in crass position where the patient is asked to place the back on his or her ipsilateral hand in the lower lumbar region and the elbow is kept close to the body. Another position that can be used is Modified Crass position where the patient is asked to place his or her hand on the ipsilateral hip area.

MRI

PATIENT POSITION: The patient lies in supine position with arm in mild external rotation. This position allows good assessment of anterior capsular components and subscapularis muscle.

COIL: The surface coil is used for imaging the shoulder which helps in producing images with high signal to noise ratio and improved spatial resolution.

SEQUENCES: Standard MRI of Shoulder at our institute includes T1W, T2W, PD-SPIR and FFE sequences in various planes.

Field of view of 160 mm x 160 mm and slice thickness of 3-4 mm is used and images are acquired in transaxial, coronal oblique and Sagittal oblique planes. Overall the bones, muscles, tendons and neurovascular structures are fully evaluated with integration of all three planes.

Table 1: Patient characteristics

It shows that out of the total participants, 15 are female, which constitutes 30% of the group, while 35 are male, making up 70% of the group. The data indicates that 34% of the participants are associated with the left side, while 66% are associated with the right side. The majority of respondents, comprising 88%, reported experiencing pain. A very small proportion, merely 2%, reported pain accompanied by swelling. Additionally, 10% of the sample cited trauma as the cause of their discomfort.

Table 2: Distribution of tendon lesions on USG and MRI

Among those with lesions, the supraspinatus tendon was most frequently affected, with 12 subjects (24%) showing a full tear and 6 subjects (12%) a partial tear. Additionally, there were 2 cases (4%) of supraspinatus tendinosis. Partial thickness tears in the subscapularis tendon were found in 4 subjects (8%), while full thickness tears were found in 5 subjects (10%). The most common lesion was tendinosis of supraspinatus tendon observed in 20 patients (40%), followed by full thickness supraspinatus tear, observed in 13 subjects (26%), which was followed by supraspinatus partial-thickness tears (PT) in 10 subjects (20%). Subscapularis was the second most common affected tendon with partial thickness tear seen in 9 subjects (18%) and full thickness tears seen in 5(10%) cases.

Table 3: Distribution of Tendon lesion USG by Tendon lesion MRI

The sensitivity of the ultrasound (USG) in detecting tendon lesions is high at 95.65%, indicating it correctly identifies 95.65% of true tendon lesions diagnosed by MRI. However, the specificity is low at 22.22%, meaning it only correctly identifies 22.22% of non-lesions, often misclassifying non-lesions as lesions. The PPV of 51.16% indicates that when USG identifies a lesion, there is a 51.16% chance it is correct, while the NPV of 85.71% suggests that when USG identifies no lesion, it is likely correct 85.71% of the time.

Table 4: Distribution of Overall Tendinosis USG by Overall Tendinosis MRI

• Sensitivity: 25%
• Specificity: 100%.
• Positive Predictive Value (PPV): 100%.
• Negative Predictive Value (NPV):2%.

In our study involving 50 patients, tendinosis was detected by MRI in 28 cases, whereas ultrasound (USG) identified tendinosis in only 7 of these 28 patients. USG exhibited a sensitivity of 25%, indicating it detected tendinosis in only a quarter of the cases identified by MRI. However, USG had a perfect specificity of 100%, meaning it accurately identified all patients without tendinosis. The positive predictive value (PPV) of USG was also 100%, reflecting that all detected cases by USG were true positives. Conversely, the negative predictive value (NPV) was 51.2%, indicating that less than half of the patients without tendinosis were correctly identified by USG.

Table 5: Distribution of subjects by Ligament lesion on MRI and Glenoid lesion on MRI

The majority of subjects, 45 out of 50 (90%), had no ligament lesions (NIL). Among those with lesions, the superior glenohumeral ligament (SGHL) was the most frequently affected, with 4 subjects (8%) showing lesions. Lesions in the middle glenohumeral ligament (MGHL) were found in 2 subjects (4%), and the inferior glenohumeral ligament (IGHL) had lesions in 1 subject (2%). Among the observed cases, the vast majority, constituting 56%, showed no evidence of Glenoid lesions. The most common pathology was SLAP I tear found in 13 patients (26%). Additionally, 10% of cases displayed an anterior inferior Glenoid lesion and 4% a labral tear.

Table 6: Distribution of Ligament lesion USG by Ligament lesion MRI and Glenoid lesion USG by Glenoid lesion MRI

The ultrasound (USG) test for ligament lesions shows high specificity and NPV, making it reliable for ruling out ligament lesions when the test result is negative. However, its sensitivity is undefined due to the absence of true positive cases, and its PPV is 0%, meaning it fails to identify true ligament lesions when they are present. Ultrasound (USG) is highly sensitive (100%) and has a perfect negative predictive value (NPV) (100%) for detecting glenoid lesions, making it very effective for ruling out lesions when the result is negative. However,

its moderate specificity (56%) and low positive predictive value (PPV) (50%) suggest that positive findings by USG should be confirmed with MRI to ensure accurate diagnosis and avoid false positives.

Table 7: Distribution of Bursal fluid USG by Bursal fluid MRI, Synovial abnormality USG by Synovial abnormality MRI, Joint effusion USG by Joint effusion MRI and Bone joint lesion USG by Bone joint lesion MRI

Ultrasound (USG) for detecting bursal fluid has a high sensitivity (79%) and very high specificity (92%), making it quite effective in correctly identifying both the presence and absence of bursal fluid. The PPV (90%) and NPV (83%) are also high, indicating that USG is reliable for both confirming and ruling out the presence of bursal fluid. Ultrasound (USG) for detecting synovial abnormalities shows perfect sensitivity (100%), specificity (100%), PPV (100%), and NPV (100%). This means that USG is highly reliable for both confirming the presence and ruling out the absence of synovial abnormalities when compared to MRI. Both ultrasonography and MRI demonstrate perfect sensitivity (100%) in detecting joint effusion, meaning they correctly identify all positive cases. However, specificity, PPV, and NPV for MRI cannot be calculated as there were no true negatives or false positives/negatives recorded in the data. Ultrasonography, on the other hand, exhibits perfect specificity, PPV, and NPV, indicating it correctly identifies all negative cases and has a strong predictive value for both positive and negative results. Therefore, based on the provided data, ultrasonography appears to be highly reliable in both detecting and ruling out joint effusion. Both ultrasonography and MRI demonstrate identical sensitivity, specificity, PPV, and NPV in detecting bone joint lesions. They both correctly identify 60% of positive cases and have a specificity of approximately 71.1%. However, the positive predictive value (PPV) is relatively low (around 18.8%), indicating a higher likelihood of false positives. Conversely, the negative predictive value (NPV) is high (approximately 94.1%), indicating a strong ability to correctly rule out the presence of bone joint lesions.

In light of the evolving landscape of diagnostic imaging and the growing emphasis on personalized medicine, it becomes imperative to critically evaluate the role of ultrasound and MRI in the assessment of painful shoulder pathologies. By elucidating the strengths, limitations, and comparative effectiveness of these imaging modalities, this dissertation seeks to provide a comprehensive understanding of their utility in clinical practice.

The present study reveals a significant gender disparity among participants, with males (72.55%) vastly outnumbering females (27.45%). This distribution aligns with Maravi P et al. [8] (2020) findings, where males (74%) predominated among patients with rotator cuff injuries, and females constituted only 26%. For instance, Singh A et al. [9] (2017) reported a more balanced ratio, though still male-dominant, with men constituting 56% and women 44% of the sample. The present study, with an average participant age of 49.35 years and an age range of 19 to 76 years, reveals a demographic profile that fits well within the spectrum of findings from previous research. This age distribution is comparable to Barad HV et al. [10] (2022) study, which reported a similar age range (20 to 76 years) and a slightly higher mean age of 51.2 years, with a significant concentration of patients aged 40-59 years (54%). Singh A et al. [9] (2017) study also supports this trend, with a majority of patients falling in the 46-55 years (30%) and 56-65 years (36%) age brackets.

The present study's findings indicate a notable asymmetry in shoulder issues, with 66.67% of participants experiencing problems with the right shoulder and 33.33% with the left shoulder. This distribution is consistent with several other studies, reinforcing the predominance of right shoulder afflictions. For instance, Singh A et al. [9] study (2017) reported an even higher incidence of right shoulder involvement at 77%. The present study indicates that pain is the predominant symptom among participants, with 86.27% reporting pain, 1.96% experiencing pain with swelling, and 11.76% attributing their discomfort to trauma. This high prevalence of pain aligns closely with findings from other studies, highlighting the universal nature of pain in shoulder-related conditions. Singh A et al. [9] (2017) similarly observed significant pain reports, with 70% of patients experiencing right shoulder pain and 30% left shoulder pain. This consistency in pain prevalence underscores its significance as a primary symptom in shoulder pathology.

The present study reveals a distinct pattern in the occurrence of shoulder lesions, with a notable 50.98% of cases showing no indication of lesions (NIL). This prevalence of NIL cases is significantly higher compared to the findings in studies by Singh AP et al. 11 (2017), Singh A et al. [9] (2017), and Barad HV et al. [10] (2022), which focused more on specific tendon abnormalities. The present study reveals that fluid presence in the subacromial (SA) and subdeltoid (SD) bursa was observed in 11.76% of cases, with the vast majority (88.24%) showing no detectable bursal fluid. This finding is relatively lower compared to other studies, indicating varying prevalence rates of bursal fluid detection. Maravi P et al. [8] (2020) reported subacromial fluid in 19% of cases, suggesting a higher occurrence of subacromial bursitis than found in the present study. This higher prevalence could indicate a greater degree of inflammation or different diagnostic criteria and methods used for detecting bursal fluid. The present study indicates that 90.2% of cases showed no evidence of joint effusion, with only 9.8% presenting with joint effusion. This finding is significantly lower than that reported by Maravi P et al. [8] (2020), where joint effusion was detected in 66% of cases, making it the most prevalent finding in that study. The stark contrast between the two studies can be attributed to several factors, including differences in diagnostic criteria, imaging techniques, and study populations. Joint effusion, or the accumulation of fluid within the glenohumeral joint, is often a sign of underlying pathology such as inflammation, injury, or degenerative changes.

In the present study, the distribution of tendon lesions shows that the most common lesion was tendinosis of supraspinatus tendon observed in 20 patients (40%), followed by full thickness supraspinatus tear, observed in 13 subjects (26%), which was followed by supraspinatus partial-thickness tears (PT) in 10 subjects (20%). Subscapularis was the second most common affected tendon with partial thickness tear seen in 9 subjects (18%) and full thickness tears seen in 5(10) % cases, while 27.45% of cases showed no tendon lesions (NIL). Comparing these findings with studies by Singh A et al. [9] (2017) and Maravi P et al. [8] (2020) provides a broader perspective on the prevalence and types of tendon lesions observed in rotator cuff pathology.

The present study's findings on bursal fluid accumulation reveal that the majority of cases, accounting for 88.24%, showed no evidence of bursal fluid. However, 9.8% of cases exhibited bursal fluid in both the subacromial (SA) and subdeltoid (SD) bursa, with an additional 1.96% presenting with bursal fluid around the coracoid. These figures highlight a relatively lower incidence of bursal fluid compared to findings from other studies. Singh AP et al. [11] (2017) detected subacromial-subdeltoid bursa effusion in 18 cases via ultrasound and in 8 cases via MRI, indicating variability in detection rates across imaging modalities. Similarly, subcoracoid bursa effusion was found in 11 cases with ultrasound and 2 cases with MRI. These findings underscore the utility of different imaging techniques in identifying specific bursal effusions, with ultrasound often providing more immediate and accessible assessments compared to MRI.

In the present study, the findings indicate that the majority of cases, specifically 90.2%, showed no evidence of joint effusion, while 9.8% exhibited joint effusion. This suggests that while joint effusion is present in a subset of cases, it is relatively less common overall within the study population. Joint effusion, characterized by fluid accumulation within the glenohumeral joint, can be indicative of various underlying conditions such as inflammation, trauma, or degenerative changes. Comparatively, Maravi P et al. [8] (2020) reported a higher prevalence of joint effusion, detected in 20% of cases out of a total of 100. This finding highlights a greater incidence of fluid accumulation within the glenohumeral joint in their study cohort compared to the present study.

The present study underscores the effectiveness of ultrasound (USG) in diagnosing tendon lesions within the shoulder joint, demonstrating robust performance metrics. USG exhibited a high sensitivity of 96.15% in identifying 25 out of 26 cases with tendon lesions, which were subsequently confirmed by MRI, yielding a perfect specificity and positive predictive value (PPV) of 100%. Moreover, USG accurately identified the absence of lesions in the 14 cases where MRI also showed no abnormalities, resulting in a notable negative predictive value (NPV) of 93.33%. Comparing these findings with other studies highlights variability in USG's diagnostic performance across different tendon types and study populations. For instance, Singh AP et al. [11] in 2017 reported varying sensitivities ranging from 78.72% to 83.34% for different tendons, with specificities ranging from 84.6% to 96.29%. The PPVs and NPVs also varied, reflecting the challenges and strengths of USG in detecting tendon tears accurately, depending on the specific tendon and tear characteristics.

In our study, we concluded that most common cause for painful shoulder was rotator cuff disorders which included tendon tears i.e. partial and full thickness tears and tendinosis. Among the rotator cuff tendons most common tendon to be involved was Supraspinatus. USG showed comparable results to MRI in detection of full thickness tears of rotator cuff tendons however, MRI proved to be a better modality for detection of partial thickness tears and tendinosis of rotator cuff tendons. USG showed to have high sensitivity and specificity for full thickness tears and relatively less for detection of partial thickness tears. MRI proved to be superior and provided more accurate assessment of the extent and location of the rotator cuff tendon tears.

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