多b值下表观弥散系数值对肺部良、恶性病变的诊断效能

目的  探讨不同b值扩散加权成像图像对肺部不同病变的鉴别效能。方法  对62例电子计算机断层扫描检查发现肺部占位性病变的患者，进行常规磁共振T1加权像、T2加权像及扩散加权成像扫描（测得病变表观弥散系数值采用t检验及方差分析，比较肺部良恶性病变及不同病理类型肺癌在不同b值下的表观弥散系数值是否有差异，并根据受试者工作特征曲线衡量相应的鉴别效能），分析肺部良恶性病变及不同病理类型肺癌在不同b值下的鉴别诊断效能。结果  62例患者均经病理证实，小细胞肺癌6例，11例鳞状细胞癌，8例高分化腺癌，13例低分化腺癌及24例良性病变。当b值取800 s/mm2时，高分化腺癌、中低分化腺癌、小细胞肺癌及鳞癌的表观弥散系数值分别为（1.80±0.14）×10-3 mm2/s、（1.09±0.15）×10-3 mm2/s、（0.80±0.10）×10-3 mm2/s及（1.19±0.18）×10-3 mm2/s；b值分别为200 s/mm2、500 s/mm2和800 s/mm2时，肺部良性病变表观弥散系数值分别为：（2.18±0.27）×10-3 mm2/s、（2.06±0.16）×10-3 mm2/s和（1.84±0.21）×10-3 mm2/s；恶性病变表观弥散系数值分别为（1.49±0.36）×10-3 mm2/s、（1.33±0.38）×10-3 mm2/s和（1.22±0.36）×10-3 mm2/s，肺部良恶性病变的表观弥散系数值差异有统计学意义（P <0.01）。结论  同一b值（b=200 s/mm2、500 s/mm2和800 s/mm2）下，表观弥散系数值对肺部良恶性病变及不同病理类型肺癌均有鉴别意义，且b=800 s/mm2时，高分化腺癌及中低分化腺癌鉴别效能最大。

Diagnostic efficacy of different apparent diffusion coefficient values in diagnosing different lung pathological types

Objective To explore the diagnostic efficacy of Diffusion-weighted imaging(DWI) in identifying different lung lesions at varied b values. Methods After diagnosed by CT examination, 62 lung lesions cases were examined by conventional T1WI, T2WI and DWI pulse sequence. The ADC values of lesions were measured and analyzed by t test and variance. The differences of benign and malignant lung lesions and different pathological types of lung cancer in ADC values under different b values were compared, and their diagnostic efficacy were measured by receiver operating characteristic (ROC) curve. The differential diagnostic efficacy for benign and malignant lung lesions and different pathological types of lung cancer was analysed under different b values. Results A total of 62 cases were pathologically confirmed (6 cases of small cell lung carcinoma, 11 cases of squamous cell carcinoma, 8 cases of well-differentiated adenocarcinoma, 13 cases of poorly differentiated adenocarcinoma and 24 cases of benign lesions). When the b value was 800 s/mm2, the ADC values of well-differentiated adenocarcinoma, low differentiated adenocarcinoma, small cell lung carcinoma and squamous cell carcinoma respectively were (1.80 ± 0.14) × 10-3 mm2/s, (1.09 ± 0.15) × 10-3 mm2/s, (0.80 ± 0.10) × 10-3 mm2/s and (1.19 ± 0.18) × 10-3 mm2/s respectively. When the b values respectively were 200 s/mm2, 500 s/mm2, 800 s/mm2, the ADC values of lung benign lesions were (2.18 ± 0.27) × 10-3 mm2/s, (2.06 ± 0.16) × 10-3 mm2/s, (1.84 ± 0.21) × 10-3 mm2/s respectively and malignant lesions were respectively (1.49 ± 0.36)×10-3 mm2/s, (1.33 ± 0.38) × 10-3 mm2/s, (1.22 ± 0.36) × 10-3 mm2/s respectively. The ADC values of lung benign and malignant lesions were statistically different (P < 0.001). Conclusions Under the same b value (b = 200 s/mm2, 500 s/mm2, 800 s/mm2 respectively), ADC values have great value to distinguish benign and malignant lesions of lung and different pathological types of lung carcinoma. The diagnostic efficacy is the best for well-differentiated adenocarcinomas and low differentiated adenocarcinomas when b values 800 s/mm2.