Joint Ictal-Interictal SPECT Reconstruction for Accurate Epileptic Focus Localization

 描述（由申请人提供）：癫痫是儿童和年轻人最常见的神经系统疾病之一，是一种具有重大心理社会和经济影响的毁灭性疾病。在当前的临床实践中，发作间期图像从发作图像中减去以获得发作图像。癫痫发作图像与受试者的结构MRI重叠，用于定位癫痫病灶。发作期SPECT的一个主要挑战是在癫痫发作后获得快速示踪剂注射。在临床实践中，示踪剂注射延迟数分钟并不罕见。随着示踪剂注入延迟的增加，与癫痫发作相关的统计计数变得少得多。而且，由于减影，癫痫发作图像中的总体噪声水平增加。由这两种效应引起的癫痫发作图像中的所得高方差降低了癫痫病灶定位的性能。我们提出了一种新的方法来重建发作和发作间期SPECT投影联合直接获得癫痫发作图像。因为发作和发作间期SPECT投影上的泊松噪声在该单个重建框架中被保留，所以癫痫发作图像的图像质量被极大地提高。我们还建议将点扩散函数建模和基于MR的SPECT衰减校正纳入联合SPECT重建中。我们期望我们的方法将大大提高癫痫灶定位的准确性，并具有较高的临床应用价值。

 DESCRIPTION (provided by applicant): Epilepsy, one of the most common neurological disorders in children and young adults, is a devastating disease with a major psychosocial and economic impact. In current clinical practice, interictal image is subtracted from ictal image to obtain a seizure image. The seizure image is overlapped to the subject's structural MRI for localizing epileptic focus. One major challenge of ictal SPECT is to obtain rapid tracer injection after the seizure. It is not uncommon that tracer injection is delayed by minutes in clinical practice. The statistical counts associated with the seizure become much less as the delay of the tracer injection increases. Also, the overall noise level in the seizure image is increased because of the subtraction. The resulting high variance in the seizure image caused by these two effects degrades the performance of epileptic focus localization. We propose a novel approach to reconstruct ictal and inter-ictal SPECT projections jointly to obtain the seizure image directly. Because Poisson noise on both the ictal and inter- ictal SPECT projections are preserved in this single reconstruction framework, image quality of the seizure image is greatly improved. We also propose to incorporate point spread function modeling and MR-based SPECT attenuation correction into the joint SPECT reconstruction. We expect that our method will greatly improve the accuracy of epileptic focus localization and have high clinical impact.