Systematic study on nail plate assessment: differences in nail plate shape, thickness, power Doppler signal and scanning approach

Abstract

Ultrasonography (US) of the nail is raising interest in the last years and its feasibility, quickness and amount of descriptive data may provide valuable information. Different authors presented several scanning approaches to nail complex in different pathological conditions, such as psoriasis, but no scanning protocol was ever proposed using healthy subjects as population of reference. The aim of the study was to establish a protocol for the US of nail plate and to assess whether the measurement of the nail plate is influenced by longitudinal vs transverse scan, sex, digit and hand dominance. Using high frequency probe and a Canon Aplio i800 machine, ultrasonographers took scans of nail plates of the hands from healthy subjects. Nail plate shape, thickness and power Doppler signal (PDUS) were evaluated and scans were taken both on longitudinal and transverse axis, at distal, middle and proximal portion of the nail plate or at a fixed angles of − 45°, 0° or + 45°. All the images were then revised and scored using a DICOM software, in order to allow good standards of accuracy and reproducibility. A total of 27 subjects (14 females and 13 males) were assessed. The measures did not result to differ in different portions or angles. Furthermore, no difference appears in sex or dominant vs not dominant hand. A decreasing and significant trend for nail plate thickness was found from the first to the fifth finger. Doppler signal was found in all but one subjects, with a range from almost absent to very evident. No difference was found between groups regarding PDUS. The data provided suggest that a proper scan protocol should include all the nails and evaluation should be done both on longitudinal and transverse axis. Since Doppler signal is highly variable in healthy subjects, its presence should be carefully considered as pathological finding. Observations provided by this study clarify important points of the scanning technique and solve doubts related to which nails should be scanned and where to evaluate quantitative parameters.

Ultrasound clinical references of the healthy toenail unit

“…Of the five parameters assessed in this study, only nail plate thickness and distance from the center of the distal phalange to the nail plate have been addressed by other authors using ultrasound, although the available data refer to the hand (Bellinato et al, 2022; Cecchini et al, 2009; De Rossi et al, 2021; Idolazzi et al, 2018; Idolazzi et al, 2019; Marina et al, 2016; Mondal et al, 2018; Naredo et al, 2019; Ureyen et al, 2018; Wortsman et al, 2004), and therefore any interpretation is problematic because there is evidence to support differences between the two models (hand and foot). For nail plate thickness, the literature includes a study on the toenail unit (Mingorance Álvarez et al, 2021).…”

“…The literature includes studies on ultrasound parameters of the nail, in all cases in the fingernail unit (Bellinato et al, 2022; Cecchini et al, 2009; De Rossi et al, 2021; Idolazzi et al, 2018; Idolazzi et al, 2019; Mondal et al, 2018; Naredo et al, 2019; Wollina et al, 2001; Wortsman et al, 2004). Only two of these studies (Bellinato et al, 2022; Cecchini et al, 2009) were performed on healthy participants.…”

“…The literature includes studies on ultrasound parameters of the nail, in all cases in the fingernail unit (Bellinato et al, 2022; Cecchini et al, 2009; De Rossi et al, 2021; Idolazzi et al, 2018; Idolazzi et al, 2019; Mondal et al, 2018; Naredo et al, 2019; Wollina et al, 2001; Wortsman et al, 2004). Only two of these studies (Bellinato et al, 2022; Cecchini et al, 2009) were performed on healthy participants. The others compared ultrasound parameters between healthy subjects and patients diagnosed with systemic skin and nail disorders, including psoriasis, psoriatic and rheumatoid arthritis, and systemic lupus erythematosus.…”

Ultrasonographic Evaluation of Nail Involvement in Patients With Axial Spondyloarthritis

“…Also, the thicknesses of the nail plates decreased from the first to the fifth finger, in accordance with the literature. 23 In studies conducted with PsA patients, nail plate thicknesses were found to be between 0.15 and 0.86 mm. 24,25 The high level of variability between measurements may be related to patient selection.…”

“…In studies conducted in PsA cases, the nail bed thicknesses were measured between 1.76 and 2.5 mm. [20][21][22][23][24][25][26] Some studies reported that the nail bed thickness above 2.0 mm should be defined as a sign of nail PsO. 6,27 In contrast to other studies, Marina et al found no significant difference in the nail bed thicknesses of PsA cases compared to healthy controls.…”