基于原始数据域噪声模拟的功能性心脏CT成像协议优化
Protocol Optimization for Functional Cardiac CT Imaging Using Noise Emulation in the Raw Data Domain
AI总结：
本文提出一种投影域噪声模拟方法，从高剂量4D心脏CT数据生成准确的低剂量模拟图像，并引入图像质量指标以优化不同体型患者的扫描协议，实现功能性心脏CT成像的剂量最小化。
摘要：
四维（4D）宽覆盖计算机断层扫描（CT）是测量心肌机械功能的有效成像方式。然而，在多个心动周期中重复进行CT测量仍是一个令人担忧的问题。本文提出了一种投影域噪声模拟方法，可从高剂量扫描生成准确的低剂量（毫安调制）4D心脏CT扫描，从而能够优化协议，在尽可能低的合理剂量水平下为功能性心脏分析提供足够的图像质量。针对目标低剂量毫安调制曲线，所提出的噪声模拟方法在投影域向高剂量数据注入适当幅度和相关性（correlation）的量子噪声和电子噪声。提出了空间变化的探测器增益项及其校准方法，以进一步提高噪声模拟的准确性。为确定低剂量阈值，提出了一种基于未落入探测器非线性区域的投影射线数量的投影域图像质量（IQ）指标。实验使用体模和临床数据验证了噪声模拟方法。对于体模和临床数据，低剂量模拟图像在噪声幅度、伪影和纹理方面均与真实低剂量图像相似。所提出的通道相关探测器增益项进一步提高了模拟准确性。利用所提出的IQ指标，为不同体型患者的低剂量4D心脏CT采集计算了推荐的kVp和mA设置。总之，本文描述了一种为基于原始数据的低剂量模拟框架估计系统相关参数的详细方法。所提出的低剂量模拟方法可用于前瞻性地选择针对患者个体的功能性心脏CT最小剂量协议。
英文摘要：
Four-dimensional (4D) wide coverage computed tomography (CT) is an effective imaging modality for measuring the mechanical function of the myocardium. However, repeated CT measurement across several heartbeats is still a concern. A projection-domain noise emulation method is presented to generate accurate low-dose (mA modulated) 4D cardiac CT scans from high-dose scans, enabling protocol optimization to deliver sufficient image quality for functional cardiac analysis while using a dose level that is as low as reasonably achievable. Given a targeted low-dose mA modulation curve, the proposed noise emulation method injects both quantum and electronic noise of proper magnitude and correlation to the high-dose data in projection domain. A spatially varying detector gain term as well as its calibration method were proposed to further improve the noise emulation accuracy. To determine the low dose threshold, a projection domain image quality (IQ) metric was proposed that is based on the number of projection rays that do not fall under the non-linear region of the detector. Experiments were performed to validate the noise emulation method with both phantom and clinical data. For both phantom and clinical data, the low-dose emulated images exhibited similar noise magnitude, artifacts, and texture to that of the real low-dose images. The proposed channel-dependent detector gain term resulted in additional increase in emulation accuracy. Using the proposed IQ metric, recommended kVp and mA settings were calculated for low dose 4D Cardiac CT acquisitions for patients of different sizes. In conclusion, a detailed method to estimate system-dependent parameters for a raw-data based low dose emulation framework was described. The proposed low-dose emulation method can be used to prospectively select patient-specific minimal-dose protocols for functional cardiac CT.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
