MRI弥散加权成像鉴别肺结核与肺炎价值初探

The value of diffusion weighted imaging in differential diagnosis of pulmonary tuberculosis and pneumonia

目的探讨MRI弥散加权成像(diffusion weighted imaging,DWI)在肺结核与肺炎鉴别诊断中的应用价值。方法收集就诊并进行CT和MRI检查的肺炎与肺结核患者共47例。肺结核主要表现为结核实变、结核空洞、结核球,肺炎则包括较大实变区。DWI检查中b值分别取0、500和800s/mm2,根据图像信噪比及噪声比筛选出最佳扫描b值。在最佳b值下观察各种肺结核病变类型与肺炎的MRI信号特点,并比较其表观弥散系数(apparent diffusion coefficient,ADC)值的差别。结果肺炎实变组与肺结核实变组在T1WI序列差异无统计学意义;在T2WI序列中,肺结核实变组病变/脊髓信号高于肺炎实变组,差异有统计学意义(P<0.05)。结核各病变类型与肺炎实变间ADC值比较:肺炎实变组高于结核实变组,结核实变组与结核球组高于结核空洞洞壁组,差异有统计学意义(P<0.05);结核实变组与结核球组间差异无统计学意义(P>0.05);肺炎实变组与结核球组间差异无统计学意义(P>0.05)。结论肺炎实变的ADC值高于肺结核实变和肺结核空洞洞壁。DWI可作为除CT以外鉴别肺结核与肺炎的重要手段。

Objective To explore the value of MRI diffusion weighted imaging（DWI） in the differential diagnosis of tuberculosis and pneumonia.Methods A total of 47 pneumonia or pulmonary tuberculosis patients were collected, and all of them were received CT and MRI examination. The tuberculosis group included three types： consolidation, tuberculosis cavity and tuberculoma. The pneumonia group mainly manifested as consolidation. In DWI examination, b value was set as 0, 500 s and 800 s/mm 2,and the best examination b value was chosen according to signal noise ratio and contrast to noise ratio of the image. Under the best b value, MRI signal character and apparent diffusion coefficient（ADC） values between the three types of tuberculosis and pneumonia was interpreted.Results The difference between pneumonia consolidation phase and pulmonary tuberculosis consolidation in T 1WI was not significant statistically. In T 2WI, signal/spinal cord of tuberculosis consolidation was higher than that of pneumonia consolidation phase, which had statistical difference（ P 〈 0.05）. The ADC value comparison between pulmonary tuberculosis types and pneumonia consolidation： ADC value of pneumonia group was higher than that of the tuberculosis consolidation group, the ADC value of tuberculosis consolidation and tuberculoma were higher than that of tuberculosis cavity wall, and they had statistical difference（ P 〈 0.05）. There was not statistically different between tuberculosis consolidation and tuberculoma（ P 〉 0.05）. There was not statistically different between pneumonia consolidation and tuberculoma（ P 〉 0.05）.Conclusion ADC value of pneumonia group is higher than that of the tuberculosis consolidation, tuberculoma and tuberculosis cavity wall. DWI can be used as an important way to identify tuberculosis and pneumonia besides CT.