Quantitative analysis of the anatomical changes in the scalp and hair follicles in androgenetic alopecia using magnetic resonance imaging

Abstract

Background Although the structural changes of the scalp in androgenetic alopecia (AGA) have been reported, these changes have been poorly understood. It is expected that modern MRI would visualize the scalp anatomy in vivo. This study aimed to explore whether AGA causes (a) changes in the thickness of the scalp, (b) anatomical changes in the hair follicles, and (c) changes in the signal intensity of MRI. Materials and Methods Twenty‐seven volunteers underwent MRI for hair and scalp (MRH) and were categorized into two according to the Hamilton‐Norwood Scale: the “AGA group” and the “normal group.” Two radiologists analyzed the thickness and signal intensity of the scalp, and the depth of hair follicles. These measurements were compared between the two groups. Results The thickness of the hypodermis and the entire scalp was significantly thinner in the AGA group than in the control group. The AGA group had significantly shallower depth of hair follicles and relative depth of the hair follicles to that of the entire scalp than the normal group. The hypodermis showed higher signal intensity in the AGA group than the normal group. Conclusion MRH allowed noninvasive visualization of the scalp anatomy and demonstrated the thinner nature of the entire scalp and hypodermis, along with the shallower depth of the hair follicles in the AGA group in comparison to the normal group. Additionally, MRH demonstrated the increased MR signal intensity in the scalp associated with AGA. MRH may be a promising new method for quantitative and objective analyses of AGA.

Diagnosis and differential diagnosis of tertiary androgenetic alopecia with severe alopecia areata based on high‐resolution MRI

“…A previous study reported the pathological and imaging findings of AGA, revealing that patients with AGA had reduced scalp thickness and thinner subcutaneous tissue layer compared with healthy controls. 22 Our findings were consistent with the previous results. At the vertex, the subcutaneous tissue layer was not statistically significantly different in patients with severe alopecia areata compared with healthy volunteers.…”

“…We found that the scalp and subcutaneous layer were thinner than healthy volunteers in patients with tertiary AGA at the vertex. A previous study reported the pathological and imaging findings of AGA, revealing that patients with AGA had reduced scalp thickness and thinner subcutaneous tissue layer compared with healthy controls 22 . Our findings were consistent with the previous results.…”

Skin ultrasonography and magnetic resonance; new clinical applications and instrumentation

“…Furthermore, recent reports demonstrated the utility of MRI in evaluating dermatofibrosarcoma tumors 27 as with tumors mentioned above in this paragraph MRI was useful in designing a surgical excision and in differentiating between this tumor and other lesions. 27 New skin/skin related MRI diagnostic applications include MRI evaluation of scalp alopecia 28,29 (primary use is to evaluate effectiveness of new therapies-see MRS discussion below), abnormal brain MRI findings in patients with atopic deramtitis 30 and use of brain functional MRI to evaluate changes induced by skin pricking/itch/pain sensation. 31,32 In the field of skin MRS no new studies appeared recently.…”

Age‐related changes in scalp biophysical parameters: A comparative analysis of the 20s and 50s age groups

“…Magnetic resonance imaging had been utilized to noninvasively analyze anatomical changes in the scalp and hair follicles in androgenetic alopecia and alopecia areata. 6,7 A previous study sought to construct a facial map based on six biophysical parameters in 20 volunteers, aged 24−83 years. 1 When the participants were divided into groups with mean ages in their 30s and 70s, the younger group displayed significantly higher TEWL and stratum corneum hydration, while exhibiting lower pH levels.…”

“…Ongoing research efforts have attempted to elucidate age‐related variations in noninvasive parameters. Magnetic resonance imaging had been utilized to noninvasively analyze anatomical changes in the scalp and hair follicles in androgenetic alopecia and alopecia areata 6,7 . A previous study sought to construct a facial map based on six biophysical parameters in 20 volunteers, aged 24−83 years 1 .…”