Inan Nagihan, Arslan Arzu, Akansel Gür, Arslan Zeliha, Elemen Levent, Demirci Ali
Department of Radiology, Kocaeli University School of Medicine, Kocaeli, Turkey.
Diagn Interv Radiol. 2009 Mar;15(1):13-8.
To evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of pleural effusions.
58 pleural effusions (21 transudative, 37 exudative) were included in this prospective study. Single-shot echo-planar spin echo DWI was performed with two b factors (500 and 1000 s/mm (2)), and apparent diffusion coefficients (ADCs) were calculated. On diffusion- weighted (DW) trace images, signal intensity (SI) of the pleural effusions was visually compared to the SI of the paraspinal muscles with the use of a 3-point scale: 0: isointense, 1: moderately hyperintense, 2: significantly hyperintense. For quantitative evaluation, effusion- to-paraspinal muscle SI ratios, and ADCs of the effusions were compared between the groups.
On visual evaluation, most of the transudative effusions were isointense, while most of the exudative effusions were hyperintense on DWI with b factors of 500 and 1000 s/mm (2). Quantitatively, with a b factor of 500 and 1000 s/mm(2), effusion-to-paraspinal muscle SI ratios of the exudative effusions were significantly higher than those of transudative effusions. The ADCs of the exudative effusions were significantly lower than those of transudative effusions (mean ADC was 3.3 x 10 (-3)+/- 0.7 mm(2)/s for exudative effusions, and 3.7 x 10 (-3)+/-0.3 mm(2)/s for transudative effusions). Setting the cutoff value at 3.6 x 10(-3), ADC had a sensitivity of 71% and a specificity of 63% for differentiating transudative from exudative effusions.
DWI may help in the differential diagnosis of pleural effusions.
评估扩散加权成像（DWI）在胸腔积液鉴别诊断中的价值。
本前瞻性研究纳入了58例胸腔积液患者（21例漏出液，37例渗出液）。采用单次激发回波平面自旋回波DWI序列，设置两个b值（500和1000 s/mm²），并计算表观扩散系数（ADC）。在扩散加权（DW）追踪图像上，使用三点量表将胸腔积液的信号强度（SI）与椎旁肌的SI进行视觉比较：0：等信号，1：中等高信号，2：显著高信号。为进行定量评估，比较了两组之间的积液与椎旁肌SI比值以及积液的ADC值。
视觉评估显示，大多数漏出液在b值为500和1000 s/mm²的DWI上为等信号，而大多数渗出液为高信号。定量分析表明，当b值为500和1000 s/mm²时，渗出液的积液与椎旁肌SI比值显著高于漏出液。渗出液的ADC值显著低于漏出液（渗出液的平均ADC为3.3×10⁻³±0.7 mm²/s，漏出液为3.7×10⁻³±0.3 mm²/s）。将临界值设定为3.6×10⁻³时，ADC鉴别漏出液与渗出液的灵敏度为71%，特异度为63%。
DWI有助于胸腔积液的鉴别诊断。
