Incomplete circle of Willis (CoW) configuration is an important risk factor for cerebrovascular pathology, namely aneurysm formation and ischemic stroke. This study was performed to characterize CoW variation using digital subtraction angiography and to identify demographic and physiologic features that may influence the risk of having an incomplete CoW configuration. MATERIALS AND METHODS: A retrospective review of 274 patients who underwent cerebral angiography by a single surgeon for any indication was conducted. Each CoW branch was graded as normal, hypoplastic, or aplastic. Univariate and multivariate regression analyses were conducted to assess the impact of age, gender, race, and certain comorbidities on CoW configuration. RESULTS: A complete CoW was identified in 37.23% of patients. In univariate analysis, patients <40 years old were more likely to have a complete CoW (odds ratio [OR]: 4.973, 95% confidence interval [CI]: 2.610-9.476, P < 0.001) as were patients <70 years old (OR: 2.849, 95% CI: 1.131-7.194, P < 0.05). Univariate analysis on demographic factors and comorbidities revealed CoW completeness to decrease with hypertension (OR: 0.575, 95% CI: 0.347-0.951, P = 0.031) and diabetes mellitus (OR: 0.368, 95% CI: 0.180-0.754, P = 0.006). Multivariable logistic regression analysis used to assess the impact of age on CoW completeness showed age to be an independent predictor of complete CoW, with an inverse correlation between increasing age and CoW completeness (OR: 0.955, 95% CI: 0.937-0.973, P < 0.001) after controlling for potential confounders including hypertension and diabetes mellitus. CONCLUSIONS: CoW configuration shows considerable variation with age; however, further investigation is required to elucidate the full impact of other demographic and vascular risk factors on CoW anatomy.

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Background: Endoscopic airway measurement (EAM) combines optical endoscopic instruments with open source image processing to accurately obtain airway dimensions. Preclinical models have demonstrated EAM as an accurate technique of airway measurement with the added advantage of characterizing multilevel stenosis, non-circular lesions, and distal obstruction. The aim of this prospective clinical study was to compare EAM to airway measurements obtained from endotracheal tube approximation (ETTA) during pediatric aerodigestive evaluation and to evaluate reproducibility of EAM across practitioners. Methods: Thirty-seven pediatric patients undergoing routine microlaryngoscopy and bronchoscopy at a single tertiary care children’s hospital were prospectively recruited. Patients undergoing emergent procedures were excluded. Two blinded reviewers performed airway measurements using ImageJ (NIH) as previously described and average values were compared to ETTA measurements. Additional EAMs were obtained from an ex vivo airway model by 28 separate clinicians and were analyzed by the same reviewers to evaluate reproducibility. Results: EAM and ETTA measurements were themselves significantly different (p = 0.0003); however, the average absolute difference between the two methods was small (Mean: 0.5 mm, 95%CI: −2.6 to 1.6 mm). There were notable differences between raters such that estimates of raters with more experience were more similar to ETTA. Despite observed differences between EAM and ETTA, endoscopic airway measurement was highly correlated with ETTA (p = 0.0002, Spearman r = 0.4185), and strong agreement was observed (Bias: −0.4974 ± 1.083 mm, 95% LOA: −2.62 to 1.625 mm). Conclusion: Clinical use of EAM is a valid and precise approach for quantification of airway luminal dimensions. This method may provide advantages over traditional ETTAs for evaluation of asymmetric airway morphology in the pediatric population.

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