Objective To explore the imaging characteristics and application of 24 MHz very high-frequency ultrasound (VHFU) in scalp examination of patients with androgenetic alopecia (AGA).

Methods AGA patients who visited Zhongnan Hospital of Wuhan University from June 2023 to June 2024 were selected as the study group, and healthy adults were recruited as the control group during the same period. The epidermal and dermal thickness, echo characteristics, inner diameter of hair follicles, and hair follicle spacing of the subjects in both groups were observed and measured by using 24 MHz VHFU. The scalp blood flow was evaluated by superb microvascular imaging, the peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) were measured, and the differences between the two groups were compared.

Results A total of 120 subjects were included, with 60 in the study group and 60 in the control group. The proportions of widened hair follicle inner diameter, hypoechoic hair follicles, and punctate blood flow were higher in the study group than in the control group. The hair follicle spacing and inner diameter were larger in the study group than in the control group, while the PSV and EDV were lower (P < 0.05). In the study group, the duration of male hair loss and epidermal thickness were greater than those of females (P < 0.05).

Conclusion VHFU can clearly display the subcutaneous hair follicle structure, determine the hair follicle status and blood supply of AGA patients, and provide a new high-resolution and non-invasive visualization tool for the clinical diagnosis of AGA.

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