Assessment of diaphragmatic dysfunction by two-dimensional speckle tracking imaging in patients with acute exacerbation of chronic obstructive pulmonary disease / 中华超声影像学杂志

ABSTRACT

Objective:To explore the application value of two-dimensional speckle tracking imaging (2D-STI) in evaluating diaphragm function, and to compare the ability of 2D-STI and conventional diaphragm ultrasonography in diagnosing diaphragmatic dysfunction and evaluating disease severity in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).Methods:A total of 58 AECOPD patients admitted to the First Affiliated Hospital of Xi′an Jiaotong University from January to October 2021 were retrospectively enrolled as AECOPD group, and 34 healthy subjects were recruited as control group during the same period. Repeatability test of diaphragmatic 2D-STI was performed. According to modified Medical Research Council (mMRC) dyspnea scores system and COPD Assessment Test (CAT), mMRC 0-1 and CAT<10 was classified as group A, mMRC≥2 and CAT≥10 was classified as group B. The baseline characteristics, conventional diaphragm ultrasonography parameters(thickening fraction and excursion) and 2D-STI parameters (longitudinal and radial strains) were compared between the AECOPD group and the control group, and the Spearman correlation between parameters of AECOPD group and forced expiratory volume in one second (FEV1) was analyzed. The differences of these parameters between group A and B were also compared. The ROC curve of conventional diaphragm ultrasonography parameters and 2D-STI parameters was plotted to differentiate group A from group B, and the diagnostic efficacy was evaluated.Results:Great intra- and inter-observer reproducibility was found for all diaphragmatic 2D-STI parameters, with ICCs above 0.80 for all measurements. The control group and the AECOPD group did not differ in age, sex and body mass index( P>0.05), whereas there were significant differences in smoking history, lung function, bilateral thickening fraction, excursion, longitudinal and radial strains( P<0.05). Compared with control group, patients in group A had a significant increase in diaphragm thickness ( P<0.05), while there was no significant difference in that between group B and control group ( P>0.05). The bilateral longitudinal strains, radial strains and thickening fraction of diaphragm were linearly correlated with FEV1 (right side rs=0.828, 0.794, 0.843, respectively; all P<0.001; left side rs=0.757, 0.704, 0.752, respectively; all P<0.001 ), while the correlation between excursion and FEV1 was not significant(right side rs=0.247, left side rs=0.253; all P>0.05). There were significant differences in bilateral longitudinal strains, radial strains and thickening fraction between group A and group B(all P<0.05), whereas there was no significant difference in excursion between the two groups ( P>0.05). ROC analysis showed bilateral longitudinal and radial strains had higher accuracy in distinguishing group A from group B than thickening fraction and excursion(right side AUCs 0.90, 0.84, 0.78 and 0.62, respectively; left side AUCs 0.85, 0.83, 0.77 and 0.62, respectively). Conclusions:2D-STI is a real-time noninvasive technique for diaphragm function assessment, which has high clinical value. Compared with conventional ultrasonography, 2D-STI shows more accuracy and effectiveness in diagnosing diaphragmatic dysfunction and evaluating disease severity of patients with AECOPD.