能谱CT碘基物质分离技术定量评价肺灌注

摘要

目的 探讨能谱CT碘基物质成像定量分析肺血流灌注分布的价值.方法 对10例可疑肺栓塞患者行能谱CT模式(GSI)肺动脉CTA,由腹侧向背侧重建5个冠状位碘基物质图像,分别为P3、P6、P9、P12及P15,测量其左、右肺上、中、下肺野ROI碘含量值,统计分析左、右肺及腹背、头足方向上碘含量的差异.结果 P3～P15图像上,ROI碘含量由腹侧向背侧递增,分别为(1.24±0.43)mg/ml、(1.52±0.42) mg/ml、(1.68±0.46)mg/ml、(1.81±0.44) mg/ml和(1.94±0.52)mg/ml,差异有统计学意义(P＜0.001),回归系数(r)为0.0436,平均变化率为(3.47±1.77) ％/cm.头足方向上,肺上、中、下野碘含量分别为(1.66±0.43) mg/ml、(1.71±0.50)mg/ml及(1.55±0.60)mg/ml,下肺野碘含量低于上、中肺野(P均＜0.001).左肺[(1.65±0.53) mg/ml]与右肺[(1.62±0.50) mg/ml]碘含量的差异无统计学意义(P＞0.05).结论 能谱CT碘基图像能够显示肺灌注沿重力方向的梯度变化,可作为评价肺血流灌注状态的新方法.%Objective To explore the value of iodine-based material decomposition images in the quantitative assessment of lung perfusion with spectral CT. Methods Ten consecutive patients with suspected pulmonary embolism underwent CT pulmonary angiography (CTPA) with spectral imaging mode (GSI). Then from ventral to dorsal, 5 groups of coronal iodine-based material decomposition images (P3, P6, P9, P12, P15) were obtained by image reconstruction, and in each coronal image, both left and right lung parenchyma were divided into three regions (up, middle, and down). In each region, the iodine density of ROI was measured. The distribution of iodine density in the direction of ventral-dorsal, head-toe and left-right was analyzed statistically. Results In the image of P3-PI 5, the iodine density of ROI increased gradually from ventral to dorsal ([1. 24 ± 0. 43]mg/ml, [1. 52 ± 0. 42]mg/ml, [1. 68 ± 0. 46]mg/ml, [1. 81±0. 44]mg/ml, [1. 94±0. 52] mg/ml, P<0. 001) , the regression coefficient (r) was 0. 0436, the average change rate was (3. 47 ± 1. 77)%/cm. From head to toe, the iodine density of up, middle and down region was (1. 66 ± 0. 43)mg/ml, (1. 71± 0. 50)mg/ml, (1.55 ± 0. 60)mg/ml, respectively, and the iodine density of down region was lower than that of up and middle region (both P< 0. 001). The iodine densities of left ([1. 65 ±0. 53]mg/ml) and right lung parenchyma ([1. 62±0. 50]mg/ml) had no significant difference (P>0. 05). Conclusion lodine-based material decomposition images can show the gradient variation of lung perfusion along the gravity direction, therefore providing a new tool to evaluate lung perfusion function.