Superb microvascular imaging for evaluating the activity of juvenile localised scleroderma: a preliminary study.

Objectives: To investigate microvascular changes in juvenile localised scleroderma (JLS) lesions using superb microvascular imaging (SMI) and assess SMI's utility in evaluating disease activity.

Methods: This prospective study enroled 16 children (7 males) with pathologically diagnosed JLS between January 2021 and June 2023. Lesions were assessed using Localised Scleroderma Cutaneous Assessment Tools, including the localised scleroderma skin activity index (LoSAI) and localised scleroderma skin damage index (LoSDI). Lesions with LoSAI scores > 0 were classified as active. The thickness and blood flow of the lesions and healthy skin layers of the contralateral site were evaluated using ultrasound. SMI was used to detect microvascular blood flow in the lesions and healthy skin, and the vascular index (VI) was calculated. The difference in VI between active lesions and healthy skin was correlated with LoSAI and total scores.

Results: Of 46 lesions, 23 were active and 23 inactive. The skin thickness of the lesion was 0.094 ± 0.024 cm, and that of the healthy site was 0.108 ± 0.026 cm (p < 0.001). The VI of the active lesions and healthy skin were 7.60 (3.60, 12.80)% and 1.10 (0.50, 2.10)%, respectively (p < 0.001). The VI of the inactive lesions and the healthy skin were 0.85 (0.00, 2.20)% and 1.60 (1.00, 3.10)%, respectively (p = 0.011). VI differences between active lesions and healthy skin positively correlated with the LoSAI clinical score (r = 0.625, p = 0.001) and total score (r = 0.842, p < 0.001).

Conclusion: SMI can quantitatively detect microvascular blood flow changes in JLS skin, indicating lesion activity and severity.

Clinical Relevance Statement: SMI is a convenient, non-invasive, technique for detecting active JLS lesions and can provide valuable information to guide treatment options.

Key Points: Current grading systems of juvenile localised scleroderma rely on subjective clinical information. Superb Microvascular Imaging identified that vascular indexes between active lesions and healthy skin positively correlated with clinical scores. Superb Microvascular Imaging effectively assesses microvascular blood flow, aiding juvenile localised scleroderma lesion activity evaluation.