Comparison of line-field confocal optical coherence tomography images with histological sections: Validation of a new method for in vivo and non-invasive quantification of superficial dermis thickness.

BACKGROUND: Line-field confocal optical coherence tomography (LC-OCT) is an imaging technique providing "optical biopsies" of the skin in real time and non-invasively. At a center optical wavelength of 1.3 µm, this innovative technology can be applied to dermo-cosmetic product development due to both high image resolution (~2 µm) and sufficient penetration (~0.5 mm). Nevertheless, the precise dermal area analyzed with LC-OCT has never been identified. In this study, the objective was to compare LC-OCT images with histological sections of the same area, in order to validate a new method for in vivo and non-invasive quantification of superficial dermis thickness. Once validated, this standardized and quantitative method was used to assess age-related changes of the superficial dermis. MATERIALS AND METHODS: Ex vivo LC-OCT acquisitions and hematoxylin-eosin-safran staining were performed on a panel of four healthy Caucasian female volunteers. In vivo LC-OCT study of skin aging was performed on a panel of 37 healthy Caucasian female divided into five different age-groups. RESULTS: Comparison with histological sections revealed that LC-OCT images allow the visualization and the quantification of the superficial portion of papillary dermis. Applied to different age-group of volunteers, LC-OCT images show a constant decrease in this superficial dermis thickness with age. CONCLUSIONS: In conclusion, we have introduced LC-OCT as a novel technique for in vivo and non-invasive evaluation of superficial dermis thickness. This approach could be used in the future to demonstrate visually and quantitatively the capacity of a dermo-cosmetic active ingredient to renormalize the structural properties of the dermis.

Reducing radiation exposure in the electrophysiology laboratory: it is more than just fluoroscopy times!

BACKGROUND: To exposure in patients undergoing cardiac electrophysiology (EP) ablation. This included the use of a "very low" dose protocol, and the impact of angulations and patient body mass index (BMI) on radiation dose as a mean to reduce exposure. METHODS: A total of 212 retrospective patient data sets were collected during EP ablation procedures on a biplane fluoroscopy system. Dose metrics were computed based on dose-area product (DAP) measured by the system for each x-ray acquisition. RESULTS: Dose baselines of different ablation procedures were established as DAP and DAP per hour, with respect to patient BMI. The use of a "very low dose" protocol reduced exposure by 62% while providing adequate image quality. With approximate left anterior oblique (LAO) 50° and right anterior oblique (RAO) 30°, DAP and DAP rate were significantly higher in LAO compared to RAO (11.2 [4.8-25.3] Gy · cm(2) vs 5.28 [2.9-11.1] Gy · cm(2) and 74.0 [38.2-136.1] Gy · cm(2)/h vs 25.0 [16.4-44.1] Gy · cm(2)/h, respectively; P < 0.001). DAP and DAP rate were also significantly higher in patients with BMI > 30 vs BMI ≤ 30 (34.2 [22.3-58.7] Gy · cm(2) vs 12.4 [6.0-26.9] Gy · cm(2) and 84.9 [68.1-120.4] Gy · cm(2)/h vs 34.2 [21.7-52.9] Gy · cm(2)/h, respectively; P < 0.001). CONCLUSION: Protocol setting, system angulation, and BMI, in particular, wider angulation in LAO compared to RAO plane, exposes patients to significant higher radiation doses. Obese patients in standard LAO plane receive six times the radiation dose of nonobese patients in RAO.

Line-field confocal optical coherence tomography for three-dimensional skin imaging.

This paper reports on the latest advances in line-field confocal optical coherence tomography (LC-OCT), a recently invented imaging technology that now allows the generation of either horizontal (x × y) section images at an adjustable depth or vertical (x × z) section images at an adjustable lateral position, as well as three-dimensional images. For both two-dimensional imaging modes, images are acquired in real-time, with real-time control of the depth and lateral positions. Three-dimensional (x × y × z) images are acquired from a stack of horizontal section images. The device is in the form of a portable probe. The handle of the probe has a button and a scroll wheel allowing the user to control the imaging modes. Using a supercontinuum laser as a broadband light source and a high numerical microscope objective, an isotropic spatial resolution of ∼1 µm is achieved. The field of view of the three-dimensional images is 1.2 mm × 0.5 mm × 0.5 mm (x × y × z). Images of skin tissues are presented to demonstrate the potential of the technology in dermatology.

Procedure planning and device positioning for left atrial appendage occlusion: insights from multi detector-row computed tomography with 3D fusion.

To compare planned and achieved device position in patients undergoing left atrial appendage occlusion (LAAO). It is unclear how devices used for LAAO position themselves compared to what is planned. All patients undergoing LAAO at our institution had pre- and post-procedural multi detector-row computed tomography (MDCT) at 3 months (N = 52). Using dedicated software, both datasets were fused to superimpose the left atria in all planes. The effective device position was traced on the post-procedural MDCT and then imported in the pre-procedural dataset to allow comparisons. Planned and effective landing zones were compared with respect to size, location and orientation. The device's final position was in a significantly larger landing zone than planned (452 ± 174 vs. 351 ± 112 mm2 for effective and planned landing zones, respectively, paired t-test: p < 0.0001), resulting in significantly less-than-intended area oversizing (41 ± 31 vs. 12 ± 28%, p < 0.0001). In terms of device orientation, there was a difference of 19.7° between the planned and effective landing zones (p < 0.0001). The Amplatzer device had a shallower-than-planned position in 70% of cases, whereas the Watchman device had a deeper-than-planned position in 75% of cases (p = 0.04). Incomplete occlusion was found in 17 patients (33%). In a multivariable model, oversizing at the effective landing zone was the only MDCT independent predictor of incomplete occlusion (OR: 0.96 per 1% increment, 95% CI 0.95-0.98, p = 0.009). MDCT fusion showed that LAAO device position and orientation are different than planned, and this is associated with incomplete occlusion of the LAA.