Evaluating disease status in idiopathic inflammatory myopathies with quantitative muscle ultrasound.

INTRODUCTION/AIMS: Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients. METHODS: Patients with IIM, excluding inclusion body myositis, were recruited along with age- and sex-matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures. RESULTS: Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing-8. DISCUSSION: Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.

Quantitative muscle ultrasound as a disease biomarker in hereditary transthyretin amyloidosis with polyneuropathy.

INTRODUCTION: There is an increasing need for a reproducible and sensitive outcome measure in patients with hereditary transthyretin amyloidosis (ATTRv) with polyneuropathy (PN) due to the emergence of disease modifying therapies. In the current study, we aimed to investigate the role of quantitative muscle ultrasound (QMUS) as a disease biomarker in ATTRv-PN. METHODS: Twenty genetically confirmed ATTRv amyloidosis patients (nine symptomatic, 11 pre-symptomatic) were enrolled prospectively between January to March 2023. Muscle ultrasound was performed on six muscles at standardized locations. QMUS parameters included muscle thickness (MT) and muscle echo intensity (EI). Twenty-five age- and sex-matched healthy controls were recruited for comparison. Significant QMUS parameters were correlated with clinical outcome measures. RESULTS: Muscle volume of first dorsal interosseus (FDI) muscle [measured as cross-sectional area (CSA)] was significantly lower in symptomatic patients compared to healthy controls and pre-symptomatic carriers (98.3 ± 58.0 vs. 184.4 ± 42.5 vs. 198.3 ± 56.8, p < 0.001). EI of biceps and FDI for symptomatic ATTRv-PN patients were significantly higher compared to the other two groups (biceps: 76.4 ± 10.8 vs. 63.2 ± 11.5 vs. 59.2 ± 9.0, p = 0.002; FDI: 48.2 ± 7.5 vs. 38.8 ± 7.5 vs. 33.0 ± 5.3, p < 0.001). CSA of FDI and EI of biceps and FDI correlated with previous validated outcome measures [polyneuropathy disability score, neuropathy impairment score, Karnofsky performance scale, Rasch-built overall disability scale, European quality of life (QoL)-5 dimensions and Norfolk QoL questionnaire-diabetic neuropathy]. CONCLUSION: QMUS revealed significant difference between ATTRv amyloidosis patients and healthy controls and showed strong correlation with clinical outcome measures. QMUS serves as a sensitive and reliable biomarker of disease severity in ATTRv-PN.

Nerve Ultrasound Score in Chronic Inflammatory Demyelinating Polyneuropathy.

Background and Objectives: Studies have suggested that, by applying certain nerve ultrasound scores, demyelinating and axonal polyneuropathies can be differentiated. In the current study, we investigated the utility of ultrasound pattern sub-score A (UPSA) and intra- and internerve cross-sectional area (CSA) variability in the diagnostic evaluation of demyelinating neuropathies. Materials and Methods: Nerve ultrasound was performed in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and acute inflammatory demyelinating polyneuropathy (AIDP) and compared to patients with axonal neuropathies. The UPSA, i.e., the sum of ultrasound scores at eight predefined measurement points in the median (forearm, elbow and mid-arm), ulnar (forearm and mid-arm), tibial (popliteal fossa and ankle) and fibular (lateral popliteal fossa) nerves, was applied. Intra- and internerve CSA variability were defined as maximal CSA/minimal CSA for each nerve and each subject, respectively. Results: A total of 34 CIDP, 15 AIDP and 16 axonal neuropathies (including eight axonal Guillain-Barré syndrome (GBS), four hereditary transthyretin amyloidosis, three diabetic polyneuropathy and one vasculitic neuropathy) were included. A total of 30 age- and sex-matched healthy controls were recruited for comparison. Significantly enlarged nerve CSA was observed in CIDP and AIDP with significantly higher UPSA in CIDP compared to the other groups (9.9 ± 2.9 vs. 5.9 ± 2.0 vs. 4.6 ± 1.9 in AIDP vs. axonal neuropathies, p < 0.001). A total of 89.3% of the patients with CIDP had an UPSA score ≥7 compared to the patients with AIDP (33.3%) and axonal neuropathies (25.0%) (p < 0.001). Using this cut-off, the performance of UPSA in differentiating CIDP from other neuropathies including AIDP was excellent (area under the curve of 0.943) with high sensitivity (89.3%), specificity (85.2%) and positive predictive value (73.5%). There were no significant differences in intra- and internerve CSA variability between the three groups. Conclusion: The UPSA ultrasound score was useful in distinguishing CIDP from other neuropathies compared to nerve CSA alone.

A model incorporating ultrasound to predict the probability of fast disease progression in amyotrophic lateral sclerosis.

OBJECTIVE: We aimed to develop a model to predict amyotrophic lateral sclerosis (ALS) disease progression based on clinical and neuromuscular ultrasound (NMUS) parameters. METHODS: ALS patients were prospectively recruited. Muscle fasciculation (≥2 over 30-seconds, examined in biceps brachii-brachialis (BB), brachioradialis, tibialis anterior and vastus medialis) and nerve cross-sectional area (CSA) (median, ulnar, tibial, fibular nerve) were evaluated through NMUS. Ultrasound parameters were correlated with clinical data, including revised ALS Functional Rating Scale (ALSFRS-R) progression at one year. A predictive model was constructed to differentiate fast progressors (ALSFRS-R decline ≥ 1/month) from non-fast progressors. RESULTS: 40 ALS patients were recruited. Three parameters emerged as strong predictors of fast progressors: (i) ALSFRS-R slope at time of NMUS (p = 0.041), (ii) BB fasciculation count (p = 0.027) and (iii) proximal to distal median nerve CSA ratio < 1.22 (p = 0.026). A predictive model (scores 0-5) was built with excellent discrimination (area under curve: 0.915). Using a score of ≥ 3, the model demonstrated good sensitivity (81.3%) and specificity (91.0%) in differentiating fast from non-fast progressors. CONCLUSION: The current model is simple and can predict the probability of fast disease progression. SIGNIFICANCE: This model has potential as a surrogate biomarker of ALS disease progression.

Nerve ultrasound can distinguish chronic inflammatory demyelinating polyneuropathy from demyelinating diabetic sensorimotor polyneuropathy.

Diabetic patients with poor glycaemic control can demonstrate demyelinating distal sensorimotor polyneuropathy (D-DSP) on electrophysiology. Distinguishing D-DSP from chronic inflammatory demyelinating polyneuropathy (CIDP) can be challenging. In this study, we investigated the role of nerve ultrasound in differentiating the two neuropathies. Nerve ultrasound findings of D-DSP patients (fulfilling the electrophysiological but not clinical criteria for CIDP) were compared with non-diabetic CIDP patients (fulfilling both criteria). We studied 108 and 95 nerves from 9 D-DSP and 10 CIDP patients respectively. CIDP patients had significantly larger cross-sectional areas of the median nerve at the mid-arm (17.0 ±â€¯12.5 vs 8.7 ±â€¯2.6; p = 0.005), ulnar nerve at the wrist (7.3 ±â€¯3.1 vs 4.1 ±â€¯1.0; p = 0.001), mid forearm (8.8 ±â€¯5.3 vs 5.5 ±â€¯1.5; p = 0.002) and mid-arm (14.5 ±â€¯14.1 vs 7.5 ±â€¯1.9; p = 0.013), and radial nerve at mid forearm (4.1 ±â€¯2.4 vs 1.2 ±â€¯0.4; p < 0.001). In comparison to D-DSP, CIDP patients had markedly larger nerves at the proximal and non-entrapment sites of the upper limbs, suggesting that nerve ultrasound is useful in differentiating the two neuropathies.