BACKGROUND Bronchoscopy is the gold standard for evaluating tracheomalacia; however, reliance on an invasive procedure limits understanding of normal airway dynamics. Self-gated ultrashort echo-time magnetic resonance imaging (UTE MRI) can assess tracheal dynamics; but has not been rigorously evaluated. METHODS This is a validation of UTE MRI diagnosis of tracheomalacia in neonates using bronchoscopy as the gold standard. Bronchoscopies were reviewed for the severity and location of tracheomalacia based on standardized criteria. The percentage change in cross-sectional area (CSA) of the trachea between end-inspiration and end-expiration was determined by UTE MRI, and receiver operating curves were utilized to determine the optimal cut-off values to predict TM and determine positive and negative predictive value. RESULTS Airway segments with tracheomalacia based on bronchoscopy had more than 3-fold change in CSA measured from MRI (54.4±56.1% vs 14.8±19.5%, p<0.0001). MRI correlated moderately with bronchoscopy for tracheomalacia severity (ρ=0.39, p=0.0001). Receiver operating curves, however, demonstrated very good ability of MRI to identify tracheomalacia (AUC=0.78). A "loose" definition (>20% change in CSA) of tracheomalacia had good sensitivity (80%) but low specificity (64%) for identifying tracheomalacia based on MRI, while a "strict" definition (>40% change in CSA) was poorly sensitive (48%) but highly specific (93%). CONCLUSIONS Self-gated UTE MRI can non-invasively assess tracheomalacia in neonates without sedation, ionizing radiation, or increased risk. This technique overcomes major limitations of other diagnostic modalities and may be suitable for longitudinal population studies of tracheal dynamics.

中文翻译：

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用于评估新生儿气管软化的超短回波时间 MRI

背景支气管镜检查是评估气管软化的金标准。然而，对侵入性手术的依赖限制了对正常气道动力学的理解。自门控超短回波时间磁共振成像（UTE MRI）可以评估气管动力学；但没有经过严格的评估。方法 这是使用支气管镜检查作为金标准对新生儿气管软化的 UTE MRI 诊断的验证。根据标准化标准，对支气管镜检查气管软化的严重程度和位置进行了审查。通过 UTE MRI 确定吸气末和呼气末气管横截面积 (CSA) 的百分比变化，并利用受试者工作曲线确定预测 TM 的最佳截止值并确定阳性和阴性预测价值。结果 根据支气管镜检查发现气管软化的气道段的 CSA 变化超过 3 倍（54.4±56.1% 对 14.8±19.5%，p<0.0001）。MRI 与支气管镜检查对气管软化严重程度有中度相关性（ρ=0.39，p=0.0001）。然而，接受者操作曲线显示 MRI 识别气管软化的能力非常好 (AUC=0.78)。气管软化的“松散”定义（CSA 变化>20%）具有良好的敏感性（80%）但特异性低（64%）基于 MRI 识别气管软化，而“严格”定义（CSA 变化>40%）敏感性差 (48%) 但特异性高 (93%)。结论 自门控 UTE MRI 可以无创评估新生儿气管软化，无需镇静、电离辐射或增加风险。