| 摘要: |
| 目的:观察99mTc腈类单光子发射计算机断层扫描(SPECT)心肌灌注显像时肝脏高放射性对下壁心肌图像的影响，并探讨其校正方法。方法:应用特制的心脏和肝脏模型。浓度研究选用心/肝放射性计数皆比为0.6,0.7,0.8,0.9和无肝脏5个点。距离研究选用心-肝距离为1,2,3,4,5,6 cm和无肝脏7个点(心/肝放射性计数比皆为0.5)。用常规对比增强型Ramp滤波函数(Ramp-C)和定量分析用Ramp滤波函数(Ramp-Q)重建图像。以Ramp-C重建的无肝脏影响的心脏下壁/前壁放射性计数比为正常,用直线相关分析不同浓度和不同距离时下壁/前壁比减低程度。结果:下壁/前壁比减低程度与心/肝比呈直线负相关(r=-0.987,P<0.01),当心/肝比为0.9时,下壁/前壁比减低程度<10％。下壁/前壁比减低程度与心-肝距离呈直线负相关(r＝-0.970, P<0.01)。Ramp-Q重建较Ramp-C重建下壁/前壁比增加2.2％？10.0％,且心/肝比越低,心-肝距离越近,增加越明显。结论:肝脏高放射性可引起重建图像下壁心肌伪影性放射性计数减低(肝-心伪影),肝脏放射性浓度越高,后者减低越严重。心脏与肝脏的距离越近,伪影越明显。Ramp-Q重建可部分校正Ramp-C重建时下壁计数减低,且计数减低程度越大,校正作用越明显。 |
| 关键词: 断层摄影术,发射型计算机,单光子 心脏 锝 |
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| The effect of high hepatic activity on the inferior wall in 99mTc-nitriles SPECT myocardial perfusion imaging:a phantom study |
| 潘文舟,乔宏庆,尚玉琨 |
| () |
| Abstract: |
| Objective: To assess the effect of high hepatic activity on the inferior myocardium in 99mTc-nitriles SPECT myocardial perfusion imaging. Methods :A heart and liver phantom was used. Images were performed in different heart-to-liver activity ratios(H/L) and heart-to-liver distances. The acquired projections were reconstructed with both contrast-enhancement(standard) and quantitative Ramp filters(Ramp-C and Ramp-Q). Considering the inferior-to-anterior (I/A) wall activity ratio in the no-liver phantom study reconstructed with Ramp-C as “normal”, the rate of decrease of I/A in other images was calculated. The relations between the rates of decrease of I/A and the various H/L and heart-to-liver distances were analyzed by linear correlation. Results: The decrease rate of I/A was linearly negatively correlated with the H/L(r=-0.986,P<0.01) and the heart-to-liver distances (r=-0.970,P<0.01).The I/A reconstructed with Ramp-Q were higher for 2.2%？10.0%than that with Ramp-C.Conclusion: High hepatic activity may create artifactual count loss in inferior wall in 99mTc-nitriles SPECT myocardial perfusion imaging.The degree of count loss is proportional to the activity level of a liver and inversely proportional to heart-to-liver distance.The extent of count loss, while tomographic images are reconstructed with Ramp-Q, is smaller than that with Ramp-C. |
| Key words: tomography, emission computed,single photon heart technetium |
