Application of 20 MHz high-frequency ultrasound in scar evaluation
10.3760/cma.j.cn114453-20220320-00075
- VernacularTitle:20 MHz高频超声在瘢痕评估中的应用
- Author:
Lu BAI
1
;
Xueqin SHI
;
Li YANG
;
Wenli ZHAO
;
Na LI
;
Juntao HAN
;
Dahai HU
Author Information
1. 空军军医大学第一附属医院烧伤与皮肤外科，西安 710032
- Keywords:
Cicatrix;
Ultrasonography;
High-frequency ultrasound;
Pathology;
Masson staining;
Vancouver scar scale;
Scar thickness
- From:
Chinese Journal of Plastic Surgery
2023;39(6):583-589
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the role of 20 MHz high-frequency ultrasound in evaluating scar thickness and morphology.Methods:The clinical data of patients with the initial stage of scar formation after burn trauma (<1 month), hypertrophic scar (1-6 months) and atrophic scar (>6 months) treated by the Department of Burn and Cutaneous Surgery, the First Affiliated Hospital of Air Force Medical University from April 2019 to December 2020, were retrospectively analyzed. All patients were evaluated by 20 MHz high-frequency ultrasound, histopathology and Vancouver scar scale (VSS). Three measurement points were randomly selected at the scar during ultrasonic examination, and the average value was recorded as the ultrasonic thickness measurement value. The scar tissue samples were collected from the site of ultrasonic examination, and HE staining and Masson staining were performed. At the same time, scar thickness was evaluated by two physicians using VSS. The difference of scar thickness assessment result among the 3 method in patients at the initial stage of scar formation, hypertrophic scar and atrophic scar was compared. Meanwhile, the relationship between the characteristics of 20 MHz high-frequency ultrasound and histopathology was compared. The measurement data of normal distribution were expressed as Mean±SD. One-way ANOVA was used for comparison among three groups, and SNK- q test was used for pairwise comparison between groups. Counting data were analyzed by Chi-square test. Results:A total of 224 patients were included, including 91 males and 133 females, aged from 1 to 34 years, with an average age of 25.7 years. There were 79 patients at the initial stage of scar formation, 102 at the hypertrophic stage, and 43 at the atrophic stage. (1) In the initial stage of scar formation, the thickness measured by 20 MHz ultrasound was about (2.01±0.68) mm, the thickness evaluated by VSS was (1.72±0.49) mm, and the thickness measured by pathological section was (2.11±0.45) mm. In the hyperplastic scar stage, the thickness measured by 20 MHz ultrasound was (4.11±0.73) mm, the thickness evaluated by VSS was (3.02±0.47) mm, and the thickness measured by pathological section was (4.27±0.44) mm. In the atrophic scar stage, the thickness measured by 20 MHz ultrasound was (1.74±0.64) mm, the thickness measured by VSS was (1.77±0.61) mm, and the thickness measured by pathological section was (1.71±0.67) mm. For scars in the above three periods, there was no statistical significance between scar thickness measured by 20 MHz high-frequency ultrasound and that measured by pathological sections(all P<0.05). In the initial stage of scar formation and hypertrophic stage, the thickness evaluated by VSS was significantly different from that measured by 20 MHz high-frequency ultrasound and pathology (all P<0.05), respectively. (2) Echo intensity was evaluated by ultrasound. In the initial stage of scar formation, the thickness of the epidermis shown by high-frequency ultrasound was close to that of the normal epidermis and presented a high-intensity echo, but there was a strip of echoless or no echo zone of <1 mm between the high-intensity echo epidermis and dermis, which looked like dermal edema. Pathology showed that there were acanthoid changes in the epidermis of the scar at this stage, rich capillaries and a small amount of collagen fibrous tissue in the dermis. In the hyperplastic scar stage, the scar epidermis still showed strong echo, while the dermis showed uneven echo, the superficial dermis showed obvious isoecho, and the deep dermis showed no echo or hypoecho. Pathology showed that the epidermis was thin and smooth, and keratosis was obvious. Collagen fibers parallel to the epidermis could be seen in the superficial layer of the dermis, with regular arrangement. Collagen fibers were increased and thickened in the deep layer of the dermis, in the shape of nodules and swirls. In the atrophic scar stage, the scar epidermis presented a strong echo, and there was no obvious demarcation between the dermis and subcutaneous tissue, presenting a uniform echo. Pathological findings showed that the epidermis became thinner with a "skin nails" -like structure, the junction between the superficial and deep dermis was not obvious, and the collagen fibers were arranged in parallel or oblique direction, and the surface boundary was unclear. Conclusion:20 MHz high-frequency ultrasound is more accurate than VSS in the assessment of thickness of hypertrophic scar, and can reflect the collagen content and moisture ratio in scar. Compared with pathological examination, it has the advantages of non-invasive and fast, and is an effective means to evaluate scar thickness and morphology.
