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In this study, we aimed to describe the immediate and long-term vascular effects of OAS in patients with peripheral arterial disease (PAD) and moderate to severely calcified lesions.Debulking the calcified atherosclerotic plaque with the orbital atherectomy system (OAS) can potentially enhance vessel compliance and increase the chance of reaching a desirable angioplasty result.A total of 7 patients were evaluated both at baseline and at 6-month follow-up. Following a diagnostic peripheral angiogram, patients with significant SFA disease had a baseline intravascular optical coherence tomography (IV-OCT) and the lesion was treated with OAS. Repeat IV-OCT was performed after atherectomy and after drug-coated balloon, if used. Patients were also evaluated with angiography and IV-OCT imaging at their 6-month follow-up.The majority of tissue removed was fibrous tissue. During follow-up, luminal volume increased for 4 of the 7 patients from baseline to 6-month follow-up and decreased in 3 patients. On average there was a 6% increase of luminal volume (P.01 compared with baseline). A recent virtual histology algorithm was used for automatic classification of IV-OCT images unaided by any reader. The algorithm used convolutional neural networks to identify regions as either calcium, fibrous, or lipid plaque, and it agreed with an expert reader 82% of the time.To the best of our knowledge, the current report is the first to describe vascular effects of OAS in medial calcified lesions immediately after and at follow-up using IV-OCT in patients with severe PAD. more...

Author(s): Gardner, Michael R; Baruah, Vikram; Vargas, Gracie; Motamedi, Massoud; Milner, Thomas E; Rylander, Henry G | Abstract: PurposeClinical intensity-based optical coherence tomographic retinal imaging is unable to resolve some of the earliest changes to Alzheimer's disease (AD) neurons. The aim of this pilot study was to demonstrate that scattering-angle-resolved optical coherence tomography (SAR-OCT), which is sensitive to changes in light scattering angle, is a candidate retinal imaging modality for early AD detection. SAR-OCT signal data may be sensitive to changes in intracellular constituent morphology that are not detectable with conventional OCT.MethodsIn this cross-sectional study, retinas of a triple transgenic mouse model of AD (3xTg-AD) were imaged alongside age-matched control mice (C57BL/6J) using SAR-OCT. A total of 32 mice (12 control, 20 3xTg-Ad) at four ages (10, 20, 30, and 45 weeks) were included in this cross-sectional study, and three retinal feature sets (scattering, thickness, and angiography) were examined between the disease and control groups.ResultsAD mice had significantly increased scattering diversity (lower SAR-OCT C parameter) at the earliest imaging time (10 weeks). Differences in the C parameter between AD and control mice were diminished at later times when both groups showed increased scattering diversity. AD mice have reduced retinal thickness compared to controls, particularly in central regions and superficial layers. No differences in vascular density or fractional blood volume between groups were detected.ConclusionsSAR-OCT is sensitive to scattering angle changes in a 3xTg-AD mouse model and could provide early-stage biomarkers for neurodegenerative diseases such as AD.Translational relevanceClinical OCT systems may be modified to record SAR-OCT images for non-invasive retinal diagnostic imaging of patients with neurodegenerative diseases such as AD. more...

Optical coherence tomography (OCT) retinal imaging contributes to understanding central nervous system (CNS) diseases because the eye is an anatomical “window to the brain” with direct optical access to nonmylenated retinal ganglion cells. However, many CNS diseases are associated with neuronal changes beyond the resolution of standard OCT retinal imaging systems. Though studies have shown the utility of scattering angle resolved (SAR) OCT for particle sizing and detecting disease states ex vivo, a compact SAR-OCT system for in vivo rodent retinal imaging has not previously been reported. We report a fiber-based SAR-OCT system (swept source at 1310 nm ± 65 nm, 100 kHz scan rate) for mouse retinal imaging with a partial glass window (center aperture) for angular discrimination of backscattered light. This design incorporates a dual-axis MEMS mirror conjugate to the ocular pupil plane and a high collection efficiency objective. A muring retina is imaged during euthanasia, and the proposed SAR-index is examined versus time. Results show a positive correlation between the SAR-index and the sub-cellular hypoxic response of neurons to isoflurane overdose during euthanasia. The proposed SAR-OCT design and image process technique offer a contrast mechanism able to detect sub-resolution neuronal changes for murine retinal imaging. more...

The adoption of intravascular optical coherence tomography (IVOCT) by cardiologists has been limited partially by the complexity of image interpretation, which is difficult even for expert readers. Identification of thin-cap fibroatheroma (TCFA), in particular, is problematic since other plaque more...

Intravascular optical coherence tomography use in the cardiac catheterization laboratory setting has been limited, in part due to the complexity of image interpretation. TCFA can be falsely identified due to tissue morphologies that mimic them. Fifty-four human coronary arteries were imaged ex vivo more...

Although virtual histology algorithms using intravascular ultrasound data can successfully classify plaque composition, parallel results have not been demonstrated with intravascular optical coherence tomography (IVOCT). The complexity of IVOCT images has limited its clinical acceptance despite its more...