Comparative study of three dimensional dynamic contrast-enhanced MR perfusion imaging in healthy volunteers and patients with chronic obstructive pulmonary disease / 中华放射学杂志

ABSTRACT

Objective To prospectively compare MR pulmonary perfusion imaging with quantitative HRCT for the detection of mild chronic obstructive pulmonary disease (COPD) and classification of COPD.Methods Sixty-two consecutive patients with COPD and 17 healthy volunteers underwent pulmonary function test (PFT),HRCT and MR perfusion imaging on the same day.According to the Global Initiative for Chronic Obstructive Lung Disease (GOLD),all COPD patients were classified into 4 stagesstage Ⅰ (n =19),stage Ⅱ (n =17),stage Ⅲ (n =14),stage Ⅳ (n =12).The signal intensity of perfusion defects (SIPD),signal intensity of normal lung perfusion (SInormal) on 3D MR perfusion were obtained through postprocessing and the signal intensity ratio (RSI) was calculated.The total lung volume (TLV) was calculated automatically on HRCT and the total emphysema volume (TEV) was obtained by applying -950 HU thresholds.The TEV/TLV was deduced as emphysema index (EI).Several comparisons were made between the volunteers and COPD patients by one-way ANOVA and Kruskal-Wallis test.Results The RSI,SIPD,PEI,MSI,MSD values of MRI perfusion in volunteers (43.9 ± 7.2,48.2 ± 19.7,31.4,55.7,44.1) were significantly different from those in patients with COPD (18.1 ± 8.1,47.4 ± 20.0,8.6,30.2,22.7) (P ＜ 0.01).The RSI showed a significant difference between stage Ⅰ (24.4 ± 9.8) and stage Ⅲ (15.9 ± 5.3) or Ⅳ (9.2 ± 2.7) and between stage Ⅱ (19.9 ± 3.1) and stage Ⅳ (t =4.05-6.64,P ＜0.01).However,all MRI perfusion parameters between stage Ⅰ and stage Ⅱ,stage Ⅱ and stage Ⅲ,stage Ⅲ and stage Ⅳ were no differences (t =2.00-4.46,P ＞ 0.05).The median of EI in volunteers and stage Ⅰ-Ⅳ COPD patients were 1.2,3.8,8.0,13.7,18.3,and the quartile range were 3.7,7.1,9.2,10.5,7.7,respectively.The EI in volunteers showed significant differences with that of stage Ⅱ-Ⅳ COPD and the EI of stage Ⅳ was different from that of stage Ⅱ or Ⅰ (t =-7.32--1.85,P ＜ 0.01),but there was no significant difference between volunteers and stage Ⅰ COPD (t =-1.99,P ＞ 0.05).Conclusions The RSI of MRI is more sensitive than that of HRCT for assessing mild COPD.The severity of COPD could be reflected by MRI perfusion and HRCT.