MYOCARDIAL VIABILITY--NUCLEAR TECHNIQUES

门控铊成像与多头SPECT区分衰减 常规临床研究中的心肌损伤 ~（99）Tc-m标记心电门控心肌灌注研究 允许评价区域收缩期壁增厚（SWT）， 低灌注 然而，门控铊（Tl）图像没有获得 广泛接受，由于其低计数。多头的出现 伽马照相机增加Tl计数，改善图像质量， 信噪比和门控Tl（G-Tl）研究的可能性。到 为了确定G-Tl成像的实用性，我们研究了36例连续的 患者（29名男性和7名女性）被转诊为T1应激- 再分布-再注射成像，使用3头SPECT相机。 30例患者有CAD，6例患者无已知CAD。 对于每例患者， 分为4个长轴断层图像，包括整个LV和 12个具有收缩期壁的可比较区域的心肌Tl活性 评估了增厚（SWT）。 在284例轻度-中度（MM， 50-84%的峰值正常活动）和59例中的39例（65%）严重降低TI 区域（<50%的峰值）可以评估SWT。 因为区别 衰减伪影与既往心肌梗死（MI）之间的关系 临床关注，我们将注意力集中在159个MM区域， 修复了Tl缺陷。SWT在27个区域中的23个（85%）正常 无CAD的患者中，132个区域中只有64个区域（48%） 冠心病组（P<0.01）。在68个区域中，37个区域（54%）存在SWT异常 心电图Q波或心肌梗死这些数据表明，常规ECG门控 TL研究是可行的。 在异常减少的区域中， 轻度-中度固定T1缺陷，G-T1中的SWT可能有助于 区分人为的T1缺陷与真正的先前损伤。

Gated Thallium Imaging With Multiheaded SPECT Differentiates Attenuation Artifact From Myocardial Injury in Routine Clinical Studies ECG gated myocardial perfusion studies with Tc-99m labelled tracers allow evaluation of regional systolic wall thickening (SWT) in areas of hypoperfusion. However, gated thallium (Tl) images have not gained widespread acceptance, due to its low counts. The advent of multiheaded gamma cameras increases Tl counts, improving image quality, increasing signal to noise ratio and the potential for gated Tl (G-Tl) studies. To determine the utility of G-Tl imaging, we studied 36 consecutive patients (29 men and 7 women) who were referred for Tl stress- redistribution-reinjection imaging using a 3-headed SPECT camera. Thirty pts had CAD and 6 pts had no known CAD. For each pt, the LV was divided into 4 long-axis tomograms encompassing the entire LV and the myocardial Tl activity of 12 comparable regions with systolic wall thickening (SWT) was assessed. In 269 of 284 (95%) mild-moderate (MM, 50-84% of peak normal activity) and 39 of 59 (65%) severely reduced Tl regions (<50% of peak) could be assessed for SWT. Because distinction between attenuation artifact and prior myocardial infarction (MI) is of clinical concern, we directed our attention to the 159 regions with MM fixed Tl defects. SWT was normal in 23 of 27 (85%) regions in pts without CAD compared to only 64 of 132 (48%) regions in pts with known CAD (p<0.01). Abnormal SWT was present in 37 of 68 regions (54%) in pts with ECG Q-waves or MI. These data suggest that routine ECG gating of Tl studies is feasible. Among regions with anomalous reduced mild-moderate fixed Tl defects, SWT in G-Tl may be helpful in distinguishing artifactual Tl defect from true prior injury.