Division of Paediatric Respiratory Medicine and Allergology, Department of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Division of Paediatric Pulmonology and Allergology, Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Centre, Nijmegen, The Netherlands.
Magn Reson Med. 2021 Dec;86(6):3224-3235. doi: 10.1002/mrm.28947. Epub 2021 Aug 2.
Lung impairment from functional MRI is frequently assessed as defect percentage. The defect distribution, however, is currently not quantified. The purpose of this work was to develop a novel measure that quantifies how clustered or scattered defects in functional lung MRI appear, and to evaluate it in pediatric cystic fibrosis.
The defect distribution index (DDI) calculates a score for each lung voxel categorized as defected. The index increases according to how densely and how far an expanding circle around a defect voxel contains more than 50% defect voxels.
Fractional ventilation and perfusion maps of 53 children with cystic fibrosis were previously acquired with matrix pencil decomposition MRI. In this work, the DDI is compared to a visual score of 3 raters who evaluated how clustered the lung defects appear. Further, spearman correlations between DDI and lung function parameters were determined.
The DDI strongly correlates with the visual scoring (r = 0.90 for ventilation; r = 0.88 for perfusion; P < .0001). Although correlations between DDI and defect percentage are moderate to strong (r = 0.61 for ventilation; r = 0.75 for perfusion; P < .0001), the DDI distinguishes between patients with comparable defect percentage.
The DDI is a novel measure for functional lung MRI. It provides complementary information to the defect percentage because the DDI assesses defect distribution rather than defect size. The DDI is applicable to matrix pencil MRI data of cystic fibrosis patients and shows very good agreement with human perception of defect distributions.
功能磁共振成像中的肺损伤通常以缺陷百分比来评估。然而，目前尚未对缺陷分布进行量化。本研究旨在开发一种新的测量方法，量化功能性肺磁共振成像中的缺陷分布的聚集或分散程度，并在小儿囊性纤维化中进行评估。
缺陷分布指数（DDI）对分类为缺陷的每个肺体素计算一个得分。该指数随着围绕缺陷体素的扩展圆中包含超过 50%缺陷体素的密度和距离而增加。
先前使用矩阵铅笔分解 MRI 获得了 53 名囊性纤维化儿童的分通气和灌注图。在这项工作中，将 DDI 与 3 位评估者的视觉评分进行比较，评估肺缺陷的聚集程度。此外，还确定了 DDI 与肺功能参数之间的 Spearman 相关性。
DDI 与视觉评分高度相关（通气时 r = 0.90；灌注时 r = 0.88；P <.0001）。尽管 DDI 与缺陷百分比之间的相关性为中等至强（通气时 r = 0.61；灌注时 r = 0.75；P <.0001），但 DDI 可区分缺陷百分比相似的患者。
DDI 是一种新的功能性肺磁共振成像测量方法。它提供了与缺陷百分比不同的补充信息，因为 DDI 评估的是缺陷分布，而不是缺陷大小。DDI 适用于囊性纤维化患者的矩阵铅笔 MRI 数据，并且与人类对缺陷分布的感知具有非常好的一致性。
