Type I Diabetes Mellitus is a chronic autoimmune condition characterized by the destruction of insulin-producing beta cells in the pancreas, resulting in insulin deficiency and a propensity to develop ketosis.

Type II Diabetes Mellitus (T2DM) represents a heterogeneous group of metabolic disorders marked by varying degrees of insulin resistance, impaired insulin secretion, and increased hepatic glucose production. It is strongly associated with obesity.[1]

Diagnostic Criteria for Diabetes Mellitus [2]

According to established guidelines, a diagnosis of diabetes can be made based on any of the following:

• Fasting plasma glucose (FPG) ≥ 126 mg/dL (7.0 mmol/L), after at least 8 hours of fasting.
• 2-hour plasma glucose (PG) ≥ 200 mg/dL (11.1 mmol/L) during an OGTT using a 75 g glucose load.
• HbA1c ≥ 6.5% (48 mmol/mol), using NGSP-certified methods.
• Random plasma glucose ≥ 200 mg/dL in patients with classic hyperglycaemic symptoms.
• Gestational Diabetes Mellitus (GDM) is diagnosed in the second or third trimester in previously non-diabetic women.

T2DM disproportionately affects underserved and socioeconomically disadvantaged populations. Many remain undiagnosed due to the invasive, expensive, and often inconvenient nature of current screening tools. Alarmingly, nearly 50% of T2DM cases are diagnosed after irreversible complications have already set in. These include renal failure, neuropathy, retinopathy, and cardiovascular disease.

T2DM is a leading cause of ESRD, lower-limb amputations, and significantly elevates mortality risk. However, effective glycemic control can reduce complications by up to 40%.

Ultrasound as a Screening Tool in T2DM Musculoskeletal ultrasound (US) is increasingly used for shoulder pathologies, particularly in T2DM, were patients commonly present with rotator cuff disorders and adhesive capsulitis. Studies have shown that diabetic patients exhibit a hyperechoic deltoid muscle on US, independent of obesity status. This echogenicity is thought to correlate with reduced intramuscular glycogen rather than adipose infiltration alone.

Our study aimed to assess whether these qualitative ultrasound findings could be objectively quantified using the deltoid muscle-to-humeral cortex echogenicity ratio. This non-invasive, accessible method may serve as a powerful screening tool in resource-limited settings, aiding early diagnosis and reducing the burden of T2DM-related complications.

Objectives:

Evaluation of ultrasound appearance of the deltoid muscle to predict type 2 diabetes mellitus as potential non-invasive and screening test.

A time-bound, hospital-based cross-sectional study was conducted in the Department of Radiodiagnosis at M.G.M. Medical College, M.Y. Hospital, and Super-speciality Hospital, Indore, Madhya Pradesh, India. The study was carried out over a one-year period, from February 2024 to January 2025, following approval from the Institutional Scientific and Ethical Committee.

A total of 200 patients referred to the Department of Radiodiagnosis for shoulder ultrasound by other departments of M.Y. Hospital and associated hospitals, with clinical suspicion of being prediabetic or diabetic, were included.

Inclusion Criteria:

1. Obese (n=50) and non-obese (n=50) patients with Type II Diabetes Mellitus.
2. Obese (n=50) and non-obese (n=50) patients without Type II Diabetes Mellitus.
3. Patients with associated conditions such as tendinosis, bursitis, and capsulitis.
4. Patients who provided informed consent.

Exclusion Criteria:          

• Patients with a history of trauma.
• Cases of paralysis, myositis, rhabdomyolysis.
• Strain-induced myopathies.

Study Protocol:

After obtaining informed consent and providing the patient information sheet, each participant underwent detailed history-taking and clinical assessment. Ultrasound examinations were performed using a high-frequency linear transducer (7–13 MHz). The patient was seated facing the examiner.

The ultrasound probe was positioned longitudinally at the anterior aspect of the supraspinatus tendon insertion at the greater tuberosity. Measurements included grey pixel echogenicity intensity (GPEI) within three circular regions of interest (ROI) on the deltoid muscle, as well as the humeral cortex. The ratio of deltoid to humeral cortex GPEI was calculated to assess muscle echogenicity both qualitatively and quantitatively.

Table 1: DISTRIBUTION OF PATIENTS ACCORDING TO AGE AND GENDER

• T2DMis most prevalent in the 51–70 age group, regardless of obesity status.
• Younger age groups(18–30) are more common in non-diabetic groups.
• Older age group(>71) has more obese non-diabetics, which may suggest delayed onset or resilience to diabetes despite obesity.
• Overall, each group maintains a total of 50 participants for balanced comparison.

Table 2: Body Mass Index (BMI) Distribu1on of Study Participants.

Underweight and normal BMI individuals were found only in the non-obese, non-diabetic group.Overweight and obese ranges dominate in the diabetic and/or obese groups.A substantial number of males from the "non-obese" groups actually fall in higher BMI categories, suggesting that classification may also depend on factors like body composition, waist circumference, or clinical judgment.Gender imbalance in data reporting: Female entries are missing or incomplete for most categories except the "Obese with T2DM" group.

Table 3 Participants BMI, HbA1c, Blood sugar level, muscle/bone ratio and deltoid muscle echogenicity among the study.

Age, BMI, HbA1c, blood glucose, muscle-bone ratio, and muscle echogenicity all show highly significant differences between the groups.These findings support the hypothesis that T2DM—especially in obese individuals—is associated with measurable changes in muscle structure and metabolic markers, which can be assessed non-invasively using ultrasound and basic clinical data.

Case 1: 74years patient 22.9kg/m2 (BMI )and (HBA1C) 4.9%

USG images show hypoechoic deltoid muscle Deltoid humeral cortical ratio - 0.4

Case 2: 68 years patient ,28.4kg/m 2 ( BMI ) and 5.1% (HBA1C ) Nondiabetic mellitus obese patient.

USG images show hypoechoic-isoechoic deltoid muscle Deltoid humeral cortical ratio - 0.45

The study was conducted in the Department of Radiodiagnosis, Medical College Indore, involving 200 patients divided into four groups: 50 each of clinically diagnosed obese and non-obese diabetic patients, and 50 each of non-diabetic obese and non-obese individuals. All patients underwent ultrasonographic assessment for deltoid muscle echogenicity and deltoid-to-humeral cortex ratio using the grayscale pixel echogenic intensity (GPEI) scale.

Age Distribution: Our study found that the majority of T2DM patients were aged 40–69 years, with the highest prevalence in the 51–70 age group among both obese and non-obese diabetics. This is consistent with findings by Rosen et al., who also reported a higher average age among T2DM patients in their sonographic assessment cohort [3]. Soliman et al. similarly observed that the diabetic cohort skewed older, reflecting the known epidemiology of T2DM [4].

Gender Distribution: In Our cohort, females slightly outnumbered males in T2DM groups, while non-diabetic groups had more males. This aligns with observations by Soliman et al., who noted a higher prevalence of T2DM in females, potentially due to hormonal and lifestyle factors, though their study also included a substantial number of males [4].

BMI Distribution: Our findings that underweight individuals were only in non-obese groups, and that overweight/obese status was predominant in T2DM and obese non-T2DM groups, match the literature. Rosen et al. reported that obesity is a significant but not exclusive risk factor for T2DM, and that increased deltoid echogenicity is not solely explained by BMI, as obese non-diabetics did not show the same ultrasound changes as diabetics[3,4].

Blood Glucose: The stratification of blood glucose levels in Our study—highest in obese T2DM, intermediate in non-obese T2DM, and lowest in non-diabetics—mirrors the expected glycaemic trends and is consistent with the clinical profiles described by Soliman et al. and Rosen et al.[3,4].

Deltoid Muscle Echogenicity: Our observation that both obese and non-obese T2DM patients had hyperechoic deltoid muscles, while non-diabetics had hypoechoic or isoechoic muscles, is strongly supported by multiple studies. Soliman et al. demonstrated that a hyperechoic deltoid muscle is a powerful predictor of T2DM and prediabetes, with a positive predictive value of 89% for diabetes diagnosis[4,5,6]. Rosen et al. also confirmed that increased echogenicity is more pronounced in T2DM, regardless of obesity status[3,6]. The literature suggests this is due to reduced intramuscular glycogen and increased adipose infiltration, both consequences of insulin resistance[7].

HbA1c Correlation: Our finding that hyperechoic muscles correlated with higher HbA1c (>7.5% in obese T2DM, 6.5–7.5% in non-obese T2DM, <5.9% in non-diabetics) is corroborated by Abdulkareem et al., who found a significant positive correlation between muscle echo intensity and HbA1c levels[8]. De Luis Román et al. also reported that higher HbA1c is associated with greater muscle quality decline and sarcopenia in T2DM[9].

Deltoid-to-Humeral Cortex Ratio: Our reported ratios (T2DM obese: >0.6; T2DM non-obese: 0.5–0.6; obese non-T2DM: 0.3–0.4; non-obese non-T2DM: <0.3) are in line with Rosen et al., who found mean muscle/bone ratios of 0.54 for obese T2DM, 0.48 for non-obese T2DM, 0.42 for obese non-T2DM, and 0.35 for non-obese non-T2DM, with statistically significant differences between groups (P < 0.001)[3,10,11]. These ratios reflect the degree of muscle degradation and metabolic dysfunction, reinforcing the utility of quantitative ultrasound as a screening tool.

Our study shows that deltoid muscle echogenicity on ultrasound, when correlated with HbA1c, blood sugar, and BMI, can serve as a sensitive and non-invasive tool to detect Type 2 Diabetes Mellitus, especially in obese patients, aiding in early diagnosis and better care in underserved populations.

1. American Diabetes Association. (2023). Standards of Medical Care in Diabetes—2023. Diabetes Care, 46(Supplement_1), S1–S290.
2. World Health Organization. (2006). Definition and Diagnosis of DiabetesMellitus and Intermediate Hyperglycaemia WHO.
3. Rosen KA, et al. The sonographic quantitative assessment of the deltoid muscle to detect type 2 diabetes mellitus. J Ultrasound Med. 2022;41(7):1843-1851.
4. Soliman SB, et al. The Hyperechoic Appearance of the Deltoid Muscle on Shoulder Ultrasound: A Predictor of Diabetes Mellitus. J Ultrasound Med. 2020;39(2):327-334.
5. Rosen KA, et al. The Hyperechoic Appearance of the Deltoid Muscle on Shoulder Ultrasound: A Predictor of Diabetes Mellitus. J Ultrasound Med. 2020;39(2):327-334.
6. Soliman SB, et al. The Echogenic Appearance of the Diabetic Deltoid Muscle on Shoulder Ultrasound. Henry Ford Health Scholarly Commons. 2019 May 1.
7. Rosen KA, et al. The Echogenic Appearance of the Diabetic Deltoid Muscle on Shoulder Ultrasound. Henry Ford Health Scholarly Commons. 2019 May 1.
8. Abdulkareem SH, et al. Ultrasonic Evaluation of Muscle Echogenicity in the Lower Limbs in Diabetic Neuropathy. FBT. 2024;11(3):462-470.
9. de Luis Román D, et al. Diabetic Sarcopenia. A proposed muscle screening protocol for patients with diabetes. Rev Endocr Metab Disord. 2024;25(1):1-12.
10. Rosen KA, et al. A potential noninvasive and sensitive screening method? J Ultrasound Med. 2022;41(7):1843-1851.
11. Soliman SB, et al. Deltoid Ultrasound Could Help Detect Type 2 Diabetes. HCPLive. 2023 Apr 17.