摘要
目的：初步探讨CT能谱成像技术分析不同病理改变下肺灌注异常区碘及空气的分布情况。材料与方法：对70例临床怀疑肺栓塞患者行能谱CT GSI模式增强扫描，经后处理分析可获得70 keV单能CTPA图像、碘基物质图像和最小密度投影（Min IP）图像。在CTPA图中观察肺动脉内有无栓子，记录栓子位置、类型及数量。分析碘基物质图表现并记录灌注异常区的位置、类型并测量碘含量，然后对照Min IP图像分析灌注异常区肺组织形态及充气情况。结果：正常组（33例）CTPA图未见栓塞征象，碘基物质图灌注均匀。正常患者前、中、后纵隔水平肺野碘含量由腹侧向背侧呈典型梯度分布，同层面两侧肺野碘分布无显著差异（P>0.05），在Min IP图中各肺段充气均匀。栓塞组（18例）CTPA图像共发现110个栓子（38个为完全型，72个为不完全型）。不完全型栓塞中有35个表现为灌注减低，碘含量为0.62 mg/mL，Min IP图中灌注异常区肺组织充气无或轻度增加。完全型栓塞碘基物质图均表现为灌注显著减低，碘含量为0.13 mg/mL，Min IP图中栓塞肺组织呈低密度。肺磨玻璃样改变患者（5例）CTPA图正常，碘基灌注图中磨玻璃样改变区呈斑片状高灌注，碘含量为2.56 mg/mL，Min IP图中均表现为与灌注异常区形状相似的高密度影。肺动脉高压患者（6例）CTPA未见栓塞但碘基物质图呈弥漫性灌注缺损，碘含量为0.48 mg/mL，Min IP图中灌注减低区充气增加。弥漫性肺气肿（4例）患者碘基物质图呈弥漫性灌注减低，碘含量为0.20 mg/mL，Min IP图中气肿区充气增加。间质性纤维化（4例）患者碘基物质图呈明显低灌注，碘含量为-0.07 mg/mL，Min IP图充气显著降低呈高密度。结论：CT能谱肺灌注成像可以定量测量不同病理改变下肺组织内碘含量及气体分布情况，为评价肺组织不同病理改变下血流、空气的分布情况提供了一个可视化的研究方法。
Abstract
Objective: To explore the feasibility of using spectral CT to evaluate the distribution of iodine and air in pulmonary perfusion disorders with different pathological changes. Materials and Methods: Seventy patients suspected of pulmonary embolism underwent CT scanning with GE Discovery CT 750HD scanner. 70 keV CTPA images, iodine-based material decomposition images and Min IP images were acquired. Location, type and number of pulmonary emboli were observed on CTPA. Location and type of abnormal perfusion were observed on iodine-based material decomposition images, and iodine content was calculated. Aeration of abnormally perfused lung parenchyma was analyzed based on Min IP images. Results: In 33 normal persons, CTPA showed no pulmonary embolism, with even iodine distribution. Iodine content in anterior, middle and posterior regions of lung parenchyma showed gradient distribution from ventral to dorsal. There was no obvious difference between left and right lungs(P>0.05) for iodine, and air distributed homogeneously on Min IP. In 18 patients with pulmonary embolism, a total of 110 emboli were found, including 38 occlusive clots and 72 non-occlusive clots. Thirty-five cases with non-occlusive clots showed reduced perfusion(iodine content 0.62 mg/mL), and the air content presented no obvious increment. Perfusion exhibited noticeable reduction in all cases with occlusive clots(iodine content 0.13 mg/mL), and the air content increased on Min IP. Five patients with pulmonary ground-glass opacity showed areas of hyper-perfusion(iodine content 2.56 mg/mL) and reduced aeration on the Min IP. Six patients with pulmonary hypertension showed diffuse perfusion defect of iodine(iodine content 0.48 mg/mL) but normal CTPA. On Min IP, areas of increased aeration were seen, corresponding to the areas of reduced perfusion. In 4 cases of diffuse emphysema, the iodine content was 0.20 mg/mL. Areas with markedly reduced density on the Min IP matched those with reduced perfusion on the iodine maps. In 4 cases of interstitial fibrosis, reduced perfusion(iodine content -0.07 mg/mL) of the pulmonary parenchyma was found, together with reduced aeration on Min IP. Conclusions: Spectral CT imaging is able to quantitatively measure the content of iodine and the distribution of gas in lungs with different pathological changes, which can be used as a visualization of the pulmonary blood flow/ventilation changes.
关键词
肺栓塞 /
体层摄影术 /
螺旋计算机
Key words
Pulmonary embolism /
Tomography /
spiral computed
于蒙蒙;白雪冬;陈 荣;张 迪;季 洋;苏贝尔;王 丹.
能谱CT肺灌注成像评价不同病理改变肺组织通气及血流灌注情况[J]. 中国临床医学影像杂志. 2014, 25(3): 165-171
YU Meng-meng;BAI Xue-dong;CHEN Rong;ZHANG Di;JI Yang;SU Bei-er;WANG Dan.
Detection of iodine and air distribution in abnormal pulmonary perfusion using spectral CT imaging[J]. Journal of China Clinic Medical Imaging. 2014, 25(3): 165-171
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