Links J M, Becker L C, Rigo P, Taillefer R, Hanelin L, Anstett F, Burckhardt D, Mixon L
Johns Hopkins University, Baltimore, MD, USA.
J Nucl Cardiol. 2000 Sep-Oct;7(5):414-25. doi: 10.1067/mnc.2000.108350.
The diagnostic accuracy of cardiac single photon emission computed tomography (SPECT) is limited by image-degrading factors, such as heart or subject motion, depth-dependent blurring caused by the collimator, and photon scatter and attenuation. We developed correction approaches for motion, depth-dependent blur, and attenuation and performed a multicenter validation.
Motion was corrected both transversely and axially with a cross-correlation technique. Depth-dependent blurring was corrected by first back-projecting each projection and then applying a depth-dependent Wiener filter row by row. Attenuation was corrected with an iterative, nonuniform Chang algorithm, based on a transmission scan-generated attenuation map. We validated these approaches in 112 subjects, including 36 women (20 healthy volunteers, 8 angiographically normal patients, and 8 patients with coronary artery disease [CAD] found by means of angiography) and 76 men (23 healthy volunteers, 10 angiographically normal patients, and 43 patients with CAD found by means of angiography). Either technetium 99m or thallium 201 was used for emission; either gadolinium 153 or Tc-99m was used for transmission. Images were reconstructed and blindly interpreted with a 5-point scale for receiver operating characteristic analysis in 2 ways: motion correction plus a Butterworth filter, and combined motion and blur and attenuation corrections. The interpretation by means of consensus was for the overall presence of CAD and vascular territory. The receiver operating characteristic curves for overall presence and each of the 3 main coronary arteries were all shifted upward and to the left and had larger areas under the curve, for combined corrections compared with motion correction and Butterworth. Sensitivity/specificity for motion correction and Butterworth were 84/69, 64/71, 32/94, and 71/81 overall for the left anterior descending, the right coronary artery, and circumflex territories, respectively, compared with 88/92, 77/93, 50/97, and 74/95, respectively, for the combined corrections.
The proposed combined corrections for motion, depth-dependent blur, and attenuation significantly improve diagnostic accuracy, when compared with motion correction alone.
心脏单光子发射计算机断层扫描（SPECT）的诊断准确性受到多种图像质量下降因素的限制，如心脏或受检者运动、准直器导致的深度依赖性模糊以及光子散射和衰减。我们开发了针对运动、深度依赖性模糊和衰减的校正方法，并进行了多中心验证。
采用互相关技术在横向和轴向上校正运动。通过先对每个投影进行反投影，然后逐行应用深度依赖性维纳滤波器来校正深度依赖性模糊。基于传输扫描生成的衰减图，采用迭代非均匀Chang算法校正衰减。我们在112名受试者中验证了这些方法，其中包括36名女性（20名健康志愿者、8名血管造影正常患者以及8名经血管造影发现患有冠状动脉疾病[CAD]的患者）和76名男性（23名健康志愿者、10名血管造影正常患者以及43名经血管造影发现患有CAD的患者）。发射显像使用锝99m或铊201；传输显像使用钆153或锝99m。图像重建后，以5分制进行盲法解读，用于两种方式的受试者操作特征分析：运动校正加巴特沃斯滤波器，以及联合运动、模糊和衰减校正。通过共识解读来判断CAD的整体存在情况和血管区域。与运动校正和巴特沃斯滤波器相比，联合校正后，CAD整体存在情况以及三条主要冠状动脉各自的受试者操作特征曲线均向上和向左移动，曲线下面积更大。对于左前降支、右冠状动脉和回旋支区域，运动校正和巴特沃斯滤波器的灵敏度/特异度总体分别为84/69、64/71、32/94和71/81，而联合校正分别为88/92、77/93、50/97和74/95。
与单独的运动校正相比，所提出的针对运动、深度依赖性模糊和衰减的联合校正显著提高了诊断准确性。
