HDCT量化分析鉴别浆膜腔积液性质的价值

The nature of the serous cavity effusion differentiated by quantitative analysis with HDCT

目的探讨CT能谱成像量化分析鉴别浆膜腔积液性质的价值。方法回顾分析因体检或者肿瘤复查等原因进行能谱CT扫描并经证实的浆膜腔积液患者66例,并根据临床、实验室检查及影像学表现,将其分为良性浆膜腔积液(包括肝硬化性、心衰或肾衰性、炎症性、结核性)和恶性肿瘤所致的恶性浆膜腔积液(胃肠道恶性肿瘤、肺癌、乳腺癌肝脏转移和卵巢恶性肿瘤所致)。应用能谱分析软件,分别测量这些浆膜腔积液的常规混合能量CT值、不同Kev水平(40～140)Kev CT值、有效原子序数,再比较良性与恶性上述定量参数的差异,结果进行独立样本t检验。结果①混合能量CT值:良恶性之间差别无统计学意义;②良恶性积液在低能量(40～50Kev)的CT值有差异;在高能量图像上(80～140)Kev的CT值差异有统计学意义;在60～70Kev单能量(接近于混合能量)差异无统计学意义;③有效原子序数:良、恶性之间差异有统计学意义,良性组(7.54±0.21)高于恶性组(7.31±0.20)。结论浆膜腔积液的性质单凭常规混合能量及60～70Kev的CT值是无法鉴别的;而低能量图像(40～50Kev)的CT值在良恶性积液的鉴别中起到重要作用;有效原子序数对积液性质诊断有一定的价值。能谱CT为鉴别浆膜腔积液的性质提供了一种全新的多参数方法。

Objective To assess the feasibility of characterizing serous cavity effusion utilizing spectral CT imaging. Methods 66 cases of patients with serous cavity effusion underwent spectral CT imaging. In all 66 patients, benign serous cavities （liver cirrhosis, heart failure and renal failure, inflammation, and tuberculosis） and malignant serous cavities （in- cluding gastrointestinal cancers, lung cancer, liver metastasis from breast cancer, and ovarian malignancies）were selected according to laboratory examination. 140 kVp images and monochromatic images （40~140） keV were reconstructed for quantitative imaging analysis. The mean CT value and effective atomic number （eft-Z） were measured. The difference of these spectral characteristic parameters was evaluated statistically by independent-samples t test. Results （1） The CT val ues on 140 kVp polychromatic images between benign and malignant didn＇t show any statistically significant difference （ P 〉0.05） ; （2） There was statistically significant difference between benign and malignant at low energy of 40-50 keV. And statistically significant difference could be found between benign and malignant serous cavity effusion at high energy of 80 -140 keV, however, there was no statistically significant differences of the CT value at 60-70 keV （equivalent to the CT values of 140 kVp image）; （3）The eff- Z of benign （7.54±0.21） was higher than malignancy （7.31±0.20） with difference. Conclusion The nature of the serous cavity effusion is unable to be identified only by the CT values on conventional 140 kVp images and the CT values on 60~70 keV images. CT values at low energy keV（40- 50 Key）play an important role in identifying malignant and benign effusion. And the effective atomic number could be applied on identifying the na- ture of the serous cavity effusion. Spectral CT imaging provides multi-parameter method for differentiating the nature of the serous cavity effusion.