Cuddy-Walsh Sarah G, Wells R Glenn
Department of Physics, Carleton University, Ottawa, ON, Canada.
Division of Cardiology, University of Ottawa Heart Institute, H2243 - 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
J Nucl Cardiol. 2021 Aug;28(4):1284-1293. doi: 10.1007/s12350-019-01821-w. Epub 2019 Jul 22.
Dedicated cardiac SPECT cameras which employ multi-pinhole detectors have variable photon sensitivity within the camera's field-of-view such that a lower number of photon counts is typically detected from the base of the heart than from the apex. Consequently, the noise in a reconstructed image is expected to be higher at the base than at the apex of the heart.
Patient emission images were resampled to create statistical replicates which were reconstructed with and without attenuation correction. Noise images were computed using one standard deviation of the replicated images. These were evaluated for 93 patients with normal study results, each imaged with both a dual-headed parallel-hole camera and a multi-pinhole camera. Statistics for a normal database (NDB) of images from the 93 patients were also calculated.
Image noise (1.7-fold) and NDB uncertainty (1.3-fold) increase significantly from the apex-to-the base of the heart in attenuation-corrected multi-pinhole SPECT images. The differences for non-attenuation-corrected images or those acquired with a parallel-hole camera were not significant.
For best interpretation of attenuation-corrected images acquired with multi-pinhole cameras, knowledge of NDB uncertainty gradients should be taken into consideration.
采用多孔径探测器的专用心脏单光子发射计算机断层扫描（SPECT）相机在相机视野内具有可变的光子灵敏度，因此通常从心脏底部检测到的光子计数比从心尖处少。因此，重建图像中预计心脏底部的噪声高于心尖处。
对患者发射图像进行重采样以创建统计复制品，并在有和没有衰减校正的情况下进行重建。使用复制图像的一个标准差计算噪声图像。对93例检查结果正常的患者进行了评估，每位患者均使用双头平行孔相机和多孔径相机进行成像。还计算了来自这93例患者的正常数据库（NDB）图像的统计数据。
在经过衰减校正的多孔径SPECT图像中，从心脏的心尖到基部，图像噪声（1.7倍）和NDB不确定性（1.3倍）显著增加。未进行衰减校正的图像或使用平行孔相机采集的图像的差异不显著。
为了最佳地解读使用多孔径相机采集的衰减校正图像，应考虑NDB不确定性梯度的知识。
