CT-based attenuation correction in 82Rb-myocardial perfusion PET-CT:: incidence of misalignment and effect on regional tracer distribution
CT-based attenuation correction in 82Rb-myocardial perfusion PET-CT:: incidence of misalignment and effect on regional tracer distribution
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DOI：
10.1007/s00259-007-0607-y
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发表时间：
2008-02-01
影响因子：
9.1
通讯作者：
Bengel, Frank M.
中科院分区：
文献类型：
--
作者：
Lautamaeki, Riikka;Brown, Tracy L. Y.;Bengel, Frank M.
目的用于衰减校正（AC）的低剂量ct可能会引起心脏pet ct伪影。目的是评估不对准的发生率和严重程度及其对区域心肌rb -82分布的定量影响。方法对连续92例患者的休息/双嘧达莫rb -82灌注- pet - ct检查结果进行分析。采用了两种不同的扫描方案：前57名患者分别进行了休息和压力PET扫描。接下来的35例患者在休息时进行了一次CT，用于休息和应激PET的交流。在视觉上以五分制对不对齐进行评分（0=不，1=最小，2=轻度，3=中度，4=严重）。在5例灌注正常、疾病概率低的代表性患者中，在使用专用软件（三维空间；偏移幅度，5,10,14 mm）重建衰减校正数据集之前，通过移动CT与PET创建95个极化图。结果在60%的休息研究和67%的应激研究中检测到PET/CT -错位。休息对中优于应力对中（0.7 +/- 0.7 vs 1.0 +/- 0.9， P=0.03）。两种方案的比较显示对应力研究的对齐没有影响（1.0 +/- 0.9 vs 1.0 +/- 0.9， P=0.9）。定量地说，任何人为失调的最大个体影响是相对Rb-82摄取减少25%。每移动1厘米，对个体影响最大的是降低19%。前壁最常受不对准的影响，但摄取的改变也发生在所有其他节段。结论CT与PET对位不正影响心脏多节段示踪剂的区域分布。双嘧达莫后的重复CT成像并不能改善对齐。这些结果强调了在临床成像方案中改进共配准策略的必要性。
Purpose Misalignment of low-dose-CT used for attenuation correction (AC) may cause artifacts in cardiac-PET-CT. The aim was to evaluate incidence and severity of misalignment and its quantitative effects on regional myocardial Rb-82-distribution.Methods Rest/dipyridamole Rb-82-perfusion-PET-CT studies of 92 consecutive patients were analyzed for misalignment. Two different scanning protocols were employed: the first 57 patients had separate CTs for rest and stress PET. The following 35 patients had one CT at rest, used for AC of rest and stress PET. Misalignment was visually scored on a five-point scale (0=no, 1=minimal, 2=mild, 3=moderate, and 4=severe). In five representative patients with normal perfusion and low probability of disease, 95 polarmaps were created by shifting CT vs PET prior to reconstruction of attenuation-corrected data sets using dedicated software (three dimensions of space; magnitude of shifts, 5, 10, 14 mm).Results PET/CT -misalignment was detected in 60% of rest and 67% of stress studies. Alignment for rest was better than that for stress (0.7 +/- 0.7 vs 1.0 +/- 0.9, P=0.03). Comparison of the two protocols revealed no effect on the alignment of the stress study (1.0 +/- 0.9 vs 1.0 +/- 0.9, P=0.9). Quantitatively, the largest individual effect of any artificial misalignment was a 25% reduction of relative Rb-82 uptake. With a shift of 1 cm, the largest effect in an individual was a 19% decrease. Anterior wall was most frequently influenced by misalignment, but changes of uptake also occurred in all other segments.Conclusions Misalignment between CT and PET in cardiac-PET-CT influences regional tracer distribution in multiple segments. Repeated CT imaging after dipyridamole does not improve alignment. These results emphasize the need for strategies to improve coregistration in clinical imaging protocols.