Page 103 - Effects of radiotherapy and hyperbaric oxygen therapy on oral microcirculation Renee Helmers

Late radiation-induced oral microvascular changes
(score 2), and vascular network without any loops (score 3). Capillary density was analyzed by selecting a still frame from each recorded clip according to the former established criteria considering image resolution, clarity, and potential pressure artefacts.9 TCD and FCD assessment was carried out by counting the total and functional capillary loops per visual field in each frame (area of 1.80 mm2). Intra-class correlation coefficient (ICC) was performed on a sample dataset to ascertain inter-rater reproducibility agreement between examiners (I, II, and III) for buccal and gingiva FCD (ICC=0.982; p<0.001). After completing capillary enumeration for each density dataset, the results were divided by 1.80 to standardize and present findings as the mean number of capillaries per millimeter squared (cpll/mm2). MFI was scored as the predominant flow type in each quadrant as being absent (score 0), intermittent (score 1), sluggish (score 2), or normal (continuous) (score 3).5
The AVA software package (AVA v3.02, Microscan BV, Amsterdam, The Netherlands), calibrated for analysis of the CC-derived images (horizontal pitch=1.306944, vertical pitch=1.289930), was used to obtain samples of
diameter measurements from CC exported recordings of our study participants.
After performing a full vascular segmentation procedure and selecting a 5 series of vascular diameters using AVA, a digital overlay Øbv measuring tool
(containing magnitudes of 5, 10, 20, 30, 40 and 50 mm) was prepared in Adobe Photoshop (Adobe Photoshop CC 2017, Adobe Systems Incorporated, San Jose, California, USA). In each of the 4 isolated frames from the buccal mucosa, 5 of the largest vessels per quadrant (20 total) were measured for Øbv and averaged to represent the mean Øbv in each frame.
For each parameter (Fd, angioarchitecture, TCD, FCD, MFI, and buccal Øbv) four datasets were obtained, analyzed at random by two independent investigators (I and III), and averaged to represent the measurement mean at each targeted ROI.
Statistical analysis
Based on a two-tailed independent-samples t-test, a total sample size of 60 (N=30 per group) was computed with an alpha set at 5%, a power of 90%, and a large effect size of 0.86. Normality distribution of all data parameters was assessed by the Shapiro-Wilk test. Comparisons between irradiated and healthy tissue capillary density and Øbv were examined using an independent-samples t-test. As only Fd data was not normally distributed, the Mann-Whitney U test
101