Systemic sclerosis (SSc) is a connective tissue disease that results in excessive accumulation of collagen in the skin and internal organs. Overall, SSc is a rare disorder, but has a high mortality, particularly in last decade of life. To improve the survival rate, an accurate and early diagnosis is crucial. Currently, the modified Rodnan skin score (mRSS) is the gold standard for evaluating SSc progression based on clinical palpation at 17 sites on the body. However, this procedure can be time consuming, and the assessed score may be biased by the experience of the clinician, causing inter- and intraobserver variabilities. Moreover, the instrinsic elasticity of skin may further bias the mRSS assessment in the early stages of SSc, such as oedematous. To overcome these limitations, there is a need for a rapid, accurate, and objective assessment technique. Optical coherence elastography (OCE) is a novel, rapidly emerging technique, which can assess mechanical contrast in tissues with micrometer spatial resolution. In this work, we demonstrate the first use of OCE to assess the mechanical properties of control and SSc-like diseased skin non-invasively. A focused air-pulse induced an elastic wave in the skin, which was detected by a home-built OCE system. The elastic wave propagated significantly faster in SSc skin compared to healthy skin. The Young’s modulus of the SSc skin was significantly higher than that of normal skin (P<0.05). Thus, OCE was able to objectively differentiate healthy and fibrotic skin completely noninvasively and is a promising and potentially useful new technology for quantifying skin involvement in SSc.
Acute Glomerulonephritis caused by anti-glomerular basement membrane disease has a high mortality due to delayed diagnosis. Thus, an accurate and early diagnosis is critical for preserving renal function. Currently, blood, urine, and tissue-based diagnoses can be time consuming, while ultrasound and CT imaging have relatively low spatial resolution. Optical coherence tomography (OCT) is a noninvasive imaging technique that provides superior spatial resolution (micron scale) as compared to ultrasound and CT. Pathological changes in tissue properties can be detected based on the optical metrics analyzed from the OCT signal, such as optical attenuation and speckle variance. Moreover, OCT does not rely on ionizing radiation as with CT imaging. In addition to structural changes, the elasticity of the kidney can significantly change due to nephritis. In this work, we utilized OCT to detect the difference in tissue properties between healthy and nephritic murine kidneys. Although OCT imaging could identify the diseased tissue, classification accuracy using only optical metrics was clinically inadequate. By combining optical metrics with elasticity, the classification accuracy improved from 76% to 95%. These results show that OCT combined with OCE can be potentially useful for nephritis detection.
The mechanical anisotropic properties of the cornea can be an important indicator for determining the onset and severity
of different diseases and can be used to assess the efficacy of various therapeutic interventions, such as cross-linking and
LASIK surgery. In this work, we introduce a noncontact method of assessing corneal mechanical anisotropy as a
function of intraocular pressure (IOP) using optical coherence elastography (OCE). A focused air-pulse induced low
amplitude (<10 μm) elastic waves in fresh porcine corneas in the whole eye-globe configuration in situ. A phase-stabilized
swept source optical coherence elastography (PhS-SSOCE) system imaged the elastic wave propagation at
stepped radial angles, and the OCE measurements were repeated as the IOP was cycled. The elastic wave velocity was
then quantified to determine the mechanical anisotropy and hysteresis of the cornea. The results show that the elastic
anisotropy at the corneal of the apex of the cornea becomes more pronounced at higher IOPs, and that there are distinct
radial angles of higher and lower stiffness. Due to the noncontact nature and small amplitude of the elastic wave, this
method may be useful for characterizing the elastic anisotropy of ocular and other tissues in vivo completely