Bodduluri Sandeep, Bhatt Surya P, Hoffman Eric A, Newell John D, Martinez Carlos H, Dransfield Mark T, Han Meilan K, Reinhardt Joseph M
Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA.
Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Thorax. 2017 May;72(5):409-414. doi: 10.1136/thoraxjnl-2016-209544. Epub 2017 Jan 2.
Traditional metrics of lung disease such as those derived from spirometry and static single-volume CT images are used to explain respiratory morbidity in patients with COPD, but are insufficient. We hypothesised that the mean Jacobian determinant, a measure of local lung expansion and contraction with respiration, would contribute independently to clinically relevant functional outcomes.
We applied image registration techniques to paired inspiratory-expiratory CT scans and derived the Jacobian determinant of the deformation field between the two lung volumes to map local volume change with respiration. We analysed 490 participants with COPD with multivariable regression models to assess strengths of association between traditional CT metrics of disease and the Jacobian determinant with respiratory morbidity including dyspnoea (modified Medical Research Council), St Georges Respiratory Questionnaire (SGRQ) score, 6-min walk distance (6MWD) and the Body Mass Index, Airflow Obstruction, Dyspnoea and Exercise Capacity (BODE) index, as well as all-cause mortality.
The Jacobian determinant was significantly associated with SGRQ (adjusted regression coefficient β=-11.75,95% CI -21.6 to -1.7; p=0.020), and with 6MWD (β=321.15, 95% CI 134.1 to 508.1; p<0.001), independent of age, sex, race, body mass index, FEV, smoking pack-years, CT emphysema, CT gas trapping, airway wall thickness and CT scanner type. The mean Jacobian determinant was also independently associated with the BODE index (β=-0.41, 95% CI -0.80 to -0.02; p=0.039) and mortality on follow-up (adjusted HR=4.26, 95% CI 0.93 to 19.23; p=0.064).
Biomechanical metrics representing local lung expansion and contraction improve prediction of respiratory morbidity and mortality and offer additional prognostic information beyond traditional measures of lung function and static single-volume CT metrics.
NCT00608764; Post-results.
诸如源自肺量计和静态单容积CT图像的传统肺部疾病指标用于解释慢性阻塞性肺疾病（COPD）患者的呼吸发病率，但并不充分。我们假设平均雅可比行列式，一种衡量肺部随呼吸局部扩张和收缩的指标，将独立地对临床相关功能结局产生影响。
我们将图像配准技术应用于吸气-呼气配对CT扫描，并推导两个肺容积之间变形场的雅可比行列式，以描绘肺部随呼吸的局部容积变化。我们使用多变量回归模型分析了490例COPD患者，以评估疾病的传统CT指标与雅可比行列式与呼吸发病率（包括呼吸困难（改良医学研究委员会）、圣乔治呼吸问卷（SGRQ）评分、6分钟步行距离（6MWD）和体重指数、气流阻塞、呼吸困难和运动能力（BODE）指数）以及全因死亡率之间的关联强度。
雅可比行列式与SGRQ显著相关（调整后的回归系数β=-11.75，95%置信区间-21.6至-1.7；p=0.020），与6MWD也显著相关（β=321.15，95%置信区间134.1至508.1；p<0.001），独立于年龄、性别、种族、体重指数、第一秒用力呼气容积（FEV）、吸烟包年数、CT肺气肿、CT气体潴留、气道壁厚度和CT扫描仪类型。平均雅可比行列式还与BODE指数独立相关（β=-0.41，95%置信区间-0.80至-0.02；p=0.039）以及随访期间的死亡率（调整后的风险比=4.26，95%置信区间0.93至19.23；p=0.064）。
代表肺部局部扩张和收缩的生物力学指标可改善对呼吸发病率和死亡率的预测，并提供超越传统肺功能指标和静态单容积CT指标的额外预后信息。
NCT00608764；结果后。
