目的将肺孤立性实性病变 的MRI扩散成像(diffusion-weighted imaging,DWI)与MSCT诊断价值进行比 较，探讨磁共振扩散加权成像在肺孤立 性病变良恶性鉴别中的价值。方法 收集 胸部CT发现肺孤立性病变的患者38例， 周围型肺癌组30例，感染性肉芽肿组8 例，均经过病理或临床资料证实。所有 病人术前或治疗前1周内均进行磁共振 常规及DWI扫描，b值为0、600 s/mm2， 测量病灶平均表观弥散系数(apparent diffusion coefficient，ADC)值,获得 ADC诊断的最佳阈值，并对CT及MRI诊断 准确率进行比较。结果 CT诊断正确33例 (86.84%)；30例周围型肺癌的ADC值为 (1.15±0.13)×10-3mm2/s，8例感染性肉 芽肿的ADC值为1.45×10-3±0.20mm2/s。 b值为600s/mm2时ADC值的曲线下面积为 0.917，鉴别周围型肺癌及肉芽肿最佳ADC 阈值为1.35×10-3mm2/s, 敏感度和特异度 分别为96.7％和75.0％。ADC值诊断准确 30例(78.95%)，ADC结合MRI平扫诊断准确 32例(84.21%)，CT与MR两者之间诊断准确 率无明显差异(p值＞0.05)。结论 ADC值 结合MRI平扫能对肺周围型肺癌及感染性 肉芽肿提供有价值的信息，可作为肺部孤 立性病变良恶性鉴别的有效补充手段。

Objective To compare the diagnostic value of diffusion-weighted imaging (DWI) and MSCT in solitary pulmonary lesions; to explore prospectively the value of DWI in the distinguishing benign and malignant solitary pulmonary lesions. Material and Methods 38 patients with solitary pulmonary lesions detected by chest CT were recruited. 30 of which were peripheral lung cancer and 8 were infectious lesions which were all confirmed by biopsy. All patients were performed DWI MRI scans 1 week before operation or treatment with b values of 0 and 600s/mm2 , and the apparent diffusion coefficient (ADC) of lesions were measured. Receiver operating characteristic curve was used to analyze and derive the optimal threshold of ADC, and accuracy rate of CT and MRI was compared. Results 33 out of the 38 patients were diagnosed correctly by CT (86.84%). The ADC value in 30 cases of peripheral lung cancer was (1.15±0.13)×10- 3 mm2 /s, the ADC value in 8 cases of lung infectious granuloma was (1.45±0.20)×10- 3 mm2 /s. When b was 600 s/mm2 , the area under the ROC of the ADC values was 0.917. The cut-off of ADC value in differential diagnosis of peripheral lung cancer and infectious granuloma was 1.35×10-3mm2 /s.The sensitivity, specificity was 96.7％, 75.0％ respectively. 30 patients was diagnosed correctly by the ADC value (78.95%), 32 patients was diagnosed correctly by combining with unenhanced MRI and ADC (84.21%). There were no significant differences between the CT and MRI diagnostic accuracy. (P＞0.05). Conclusion The ADC value combining with unenhanced MRI can provide valuable information in the peripheral pulmonary cancer and infectious granuloma, which can be used as the effectively supplement to distinguish the benign and malignant solitary pulmonary lesions.