Sonography of the Skin at 100 MHz Enables In Vivo Visualization of Stratum Corneum and Viable Epidermis in Palmar Skin and Psoriatic Plaquesy1

Abstract

A main drawback of 20-25 MHz ultrasound units for skin imaging is their limited resolution. We used a transducer with a center frequency of 95 MHz and a resolution of 8.5 microm axially and 27 microm laterally - an almost 10-fold increase compared with 20 MHz. By means of a new scanning technology we reached a depth of field of 3.2 mm. We examined normal palmar skin, normal glabrous skin on the abdomen, the upper back, the calf and the dorsal forearm, and 35 lesions of psoriasis vulgaris. From 11 psoriatic plaques biopsies were taken for correlation with the sonograms. In normal palmar skin, the horny layer is represented as an echopoor band below the skin entry echo, traversed by echorich coils, which correspond to eccrine sweat gland ducts. The thickness of this band significantly increases after occlusive application of petrolatum. Its lower border is defined by an echorich line, representing the stratum corneum/stratum Malpighii-interface. Underneath, a second echopoor band is visible, which corresponds to the viable epidermis plus the papillary dermis, bordered by the scattered echo reflexes of the reticular dermis. This band is also visible in glabrous skin; however, the stratum corneum cannot be detected. In psoriatic lesions, the thickened horny layer appears echorich; after application of petrolatum, its echodensity decreases. Below, the acanthotic epidermis plus the dermis with the inflammatory infiltrate are represented as an echopoor band. There is an excellent correlation between the sonometric thickness of this band and the histometric thickness of the acanthosis plus the infiltrated dermis. Our results show that 100 MHz sonography is a valuable tool for in vivo examination of the upper skin layers.

A New High Frequency Ultrasound Skin Imaging System: Imaging Properties and Clinical in Vivo Results

“…Utilizing HFUS in the 100MHz range, the structures in the uppermost skin layers can be imaged with much better resolution and, consequently, much more details can be identified 17 . Furthermore, a much finer echo texture is visible in the dermis, which indicates the better spatial resolution as well.…”

The microvascular and morphostructural changes of nails in psoriatic patients with nail disease; a link between ultrasound and videocapillaroscopy findings in the nailfold

“…Patients with PND were categorized into two groups by NPT measured by US as NPT <20 mm (n=16) and NPT ≥20 mm (n=18) and the median NAPSI in two groups were 20.5 (12.2-33) and 28.5 (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), respectively (p= 0.05). There were 6 patients in type 1GS changes of psoriatic nails, 6 patients in type 2, 20 patients in type 3, and 2 patients in type 4.…”

“…US is also a non-invasive imaging method which allows viewing the anatomical and physiological details of the nails and provides information about the morphological appearance of the nail lesions, together with changes of the underlying tissue and blood flow alteration [22]. During the past decade, several studies have evaluated the usefulness of US for diagnosis, identification of disease activity and follow-up response to treatment in patients with psoriasis [23][24][25][26][27].…”

A highly compact packaging concept for ultrasound transducer arrays embedded in neurosurgical needles

“…When embedding transducer dies in a needle, the space available for the electrical and mechanical connections is extremely limited. This integration scheme requires therefore an interconnection technology that can offer a higher compactness compared to the conventional wire bonding method, which is the current state-of-the-art technique for lower frequency systems and Microultrasound (mUS) devices deployed externally (El Gammal et al 1999).…”