Background:

Although diffusion-weighted imaging (DWI) is useful for differential diagnosis between lung cancers and benign pulmonary nodules and masses (BPNMs), it is difficult to differentiate pulmonary abscesses from lung cancers because pulmonary abscesses show restricted diffusion. With this research we will present how to assess the total apparent diffusion coefficient (ADC) and inside/wall ADC ratio for these pulmonary nodules and masses (PNMs).

Methods:

The pulmonary lesions were divided into next 3 groups. There were 40 lung cancers, 41 inflammatory benign PNMs (mycobacteria disease 13, pneumonia 12, pulmonary abscess 10, other 6) and 7 noninflammatory benign PNMs. Definitions were as follows: wall ADC = ADC value in outer one-third of the lesion; inside ADC = ADC value in central two-thirds of the lesion: inside/wall ADC ratio = ratio of inside ADC/wall ADC.

Results:

Mean total ADC (1.26 ± 0.32 × 10⁻³ mm²/s) of the lung cancers was remarkably lower than that (1.53 ± 0.53) of the BPNMs. The mean total ADC values were 1.26 ± 0.32 in lung cancer, 1.45 ± 0.47 in inflammatory BPNM and 2.04 ± 0.63 in noninflammatory BPNM, and there were significant differences among them. The mean inside ADC value (1.33 ± 0.32) of the lung cancers was remarkably higher than that (0.94 ± 0.42) of the pulmonary abscesses. The mean inside/wall ADC ratio (1.20 ± 0.28) of the lung cancers was remarkably higher than that (0.74 ± 0.14) of the pulmonary abscesses.

Conclusions:

Although ADC of DWI could differentiate lung cancer from BPNM, the inside/wall ADC ratio of DWI is efficient for differentiation between lung cancer and lung abscess. The inside/wall ADC ratio of DWI strengthens a weak point of DWI.

中文翻译：

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如何区分肺癌与良性肺结节和肿块？具有表观扩散系数和内/壁表观扩散系数比的扩散加权磁共振成像的有用性

背景：

尽管弥散加权成像 (DWI) 可用于鉴别肺癌和良性肺结节和肿块 (BPNM)，但由于肺脓肿显示扩散受限，因此很难区分肺脓肿和肺癌。通过这项研究，我们将介绍如何评估这些肺结节和肿块 (PNM) 的总表观扩散系数 (ADC) 和内/壁 ADC 比率。

方法：

将肺部病变分为接下来的3组。有 40 例肺癌，41 例炎症性良性 PNM（分枝杆菌病 13 例，肺炎 12 例，肺脓肿 10 例，其他 6 例）和 7 例非炎症性良性 PNM。定义如下：壁ADC=病灶外三分之一处的ADC值；内ADC =病灶中央三分之二处的ADC值：内/壁ADC比=内ADC/壁ADC比。

结果：

肺癌的平均总ADC（1.26±0.32×10 ^-3 mm ² /s）显着低于BPNM的（1.53±0.53）。肺癌的平均总ADC值为1.26±0.32，炎症性BPNM为1.45±0.47，非炎症性BPNM为2.04±0.63，它们之间存在显着差异。肺癌的平均内ADC值（1.33±0.32）明显高于肺脓肿（0.94±0.42）。肺癌的平均内/壁ADC比（1.20±0.28）显着高于肺脓肿（0.74±0.14）。

结论：

虽然 DWI 的 ADC 可以区分肺癌和 BPNM，但 DWI 的内/壁 ADC 比率对于区分肺癌和肺脓肿是有效的。DWI的内/壁ADC比加强了DWI的弱点。