急性单发局灶肺炎的CT诊断

Acute solitary localized pneumonia: CT diagnosis

目的研究局灶肺炎ＣＴ影像的鉴别诊断价值。方法局灶肺炎２５例，均诊断或疑诊为周围型肺癌。病人年龄均在４０岁以上，其中５０～８０岁２１例，占８４％；无临床症状１３例，占５２％；痰中带血５例，占２０％。ＣＴ设备档次不同，均未做增强。结果ＣＴ表现有３种：（１）不规则结节，磨玻璃样密度，其中见少数点状高密度灶；（２）不规则形状结节，边缘较清楚，边缘毛刺，密度均匀；（３）形状规则结节，边缘清楚，密度均匀。这３种表现以第３种多见。好发生于两肺下叶背段或后基底段１５例，占６０％。除３例手术外，２２例均经抗炎治疗，２～３周吸收１８例，占２２例中的８２％。结论临床和影像有时鉴别局灶肺炎和周围型肺癌较困难。在ＣＴ上不规则形状结节且边缘有毛刺，而在胸片上边缘毛刺不明确，证明胸片有助于诊断。在相同层面上观察肺窗和纵隔窗病灶大小的变化，若纵隔窗较肺窗明显缩小多见于肺炎，肺泡癌也可有这种变化。

bjective To evaluate CT in the differential diagnosis of solitary localized pneumonia. Methods Only plain CT without contrast study was done because of different types of CT scanners weed. There were 25 cases with localized pneumonia with initial diagnosis as suspected peripheral bronchogenic carcinoma. All patients were over forty years of age ,84% 50-80 years, 13(52%) patients were asymptomatic, 5(20%)patients had bloody sputum. Results The CT features were divided into three patterns: (1) irregular nodule with relatively welldefined margin, groundglass opacity and a few punctate high densities. (2)irregular nodule with sharply circumscribed, spiculated border and homogeneous density. (3) regular nodule with relatively welldefined margin, and homogeneous density. The third type was most frequent (60%) with predilection for the dorsal segments of the lower lobes, or the posterior basal segments. Of the 25 patients 3 had operation, the remaining cases were treated as pneumonia, the lesions were resolved in 18(82%) patients in 2-3 weeks. Conclusions Sometimes it is very difficult to differentiate localized pneumonia from peripheral lung cancer on the basis of clinical presentation and imaging. The spiculated margins of irregular nodule shown on CT could be indeterminate on chest radiograph, and as a result chest radiograph is helpful in differential diagnosis of localized pneumonia. Change in size of the lesion as observed at the same crosssection scan, smaller at mediastinal window than at lung window is in favor of localized pneumonia, however,with the exception of alveolar carcinoma, treatment with antibiotic therapy for a period of 2-3 weeks,helps differentiate these diseases.