Myocardial perfusion imaging with a combined x-ray CT and SPECT system.
Myocardial perfusion imaging with a combined x-ray CT and SPECT system.
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发表时间：
1997-10
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通讯作者：
K. Kalki;S. Blankespoor;J. K. Brown;Bruce H. Hasegawa;Michael W. Dae;Marshall H. Chin;C. Stillson
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作者：
K. Kalki;S. Blankespoor;J. K. Brown;Bruce H. Hasegawa;Michael W. Dae;Marshall H. Chin;C. Stillson
我们评估了一种新的x射线CT和SPECT联合医学成像系统，用于定量测量心肌灌注动物模型中99mTc-sestamibi的体内摄取。方法获得7 ~ 10 kg猪的相关发射透射心肌图像。x射线CT图像用于生成目标特定的衰减图，该衰减图被纳入迭代ML-EM算法，用于对共配准的SPECT图像进行重建和衰减校正。SPECT图像中的像素强度以放射性核素浓度（MBq/g）为单位进行校准，然后与从切除心肌中测量的体外99mTc活性浓度进行比较。此外，利用x线CT共配图确定解剖边界，定量低灌注心肌区域。结果通过靶特异性衰减校正，提高了猪心肌体内活性浓度定量测定的准确性。然而，需要对部分体积误差进行额外的校正才能从重建的SPECT图像中检索到真实的活性浓度。结论准确的SPECT绝对定量需要对衰减和部分体积效应进行对象特异性校正。来自x射线CT图像的附加解剖信息有助于确定SPECT图像定量的兴趣区域。
UNLABELLED We evaluated a novel combined x-ray CT and SPECT medical imaging system for quantitative in vivo measurements of 99mTc-sestamibi uptake in an animal model of myocardial perfusion. METHODS Correlated emission-transmission myocardial images were obtained from 7- to 10-kg pigs. The x-ray CT image was used to generate an object-specific attenuation map that was incorporated into an iterative ML-EM algorithm for reconstruction and attenuation correction of the coregistered SPECT images. The pixel intensities in the SPECT images were calibrated in units of radionuclide concentrations (MBq/g), then compared against in vitro 99mTc activity concentration measured from the excised myocardium. In addition, the coregistered x-ray CT image was used to determine anatomical boundaries for quantitation of myocardial regions with low perfusion. RESULTS The accuracy of the quantitative measurement of in vivo activity concentration in the porcine myocardium was improved by object-specific attenuation correction. However, an additional correction for partial volume errors was required to retrieve the true activity concentration from the reconstructed SPECT images. CONCLUSION Accurate absolute SPECT quantitation required object-specific correction for attenuation and partial volume effects. Additional anatomical information from the x-ray CT image was helpful in defining regions of interest for quantitation of the SPECT images.