Department of Diagnostic Imaging, Monash Medical Centre, Southern Health, 246 Clayton Road, Clayton, Victoria 3168, Australia.
J Cardiovasc Comput Tomogr. 2011 Nov-Dec;5(6):406-11. doi: 10.1016/j.jcct.2011.10.003. Epub 2011 Oct 22.
CT myocardial perfusion imaging is an emerging CT application using density measurements of contrast-enhanced left ventricular (LV) myocardium.
Using a 320-MDCT we have consistently observed lower Hounsfield unit (HU) values in the lateral LV myocardium, potentially mimicking perfusion defects. This study aimed to evaluate contrast-enhancement patterns of the LV myocardium in normal studies.
Twenty-one clinical cases with normal coronary MDCT-based angiography findings, as determined by 2 qualified readers, were selected for retrospective evaluation. Using 8 identically sized and positioned ROIs, the HU measurements were recorded from short axis axial reconstructions through the LV myocardium in middle, apical, and basal locations. Scans were acquired on a 320-slice MDCT unit.
The middle short axis location demonstrated HU densities of 79.4 (range 42.3-162.7) in the lateral myocardial wall (regions 2, 3, and 4) compared with 103.9 (range 11.4-159.6) in the inferior, septal, and anterior walls (regions 1, 5, 6, 7, and 8; P < 0.001). HU densities for the basal slice were 82.3 (range 51.5-168.4) in the lateral wall compared with 94.9 (range 35.3-144) in the inferior, septal, and anterior walls (P < 0.001). In the apical location, HU densities were 79.9 (range 42.3-139.3) in the lateral wall compared with 100.9 (range 69.0-170.5) in the inferior, septal, and anterior walls (P < 0.001).
Normal LV myocardial enhancement using a 320-slice MDCT demonstrates significantly lower densities in the lateral wall when compared with the anterior, septal, and inferior walls in patients with normal coronary vascular anatomy. Assessment of CT myocardial perfusion studies should therefore be undertaken with caution, to prevent misrepresenting these lower-density values in the LV lateral wall.
CT 心肌灌注成像是一种新兴的 CT 应用，利用对比增强左心室（LV）心肌的密度测量。
使用 320 层 MDCT，我们一致观察到 LV 外侧心肌的 Hounsfield 单位（HU）值较低，可能模拟灌注缺陷。本研究旨在评估正常研究中 LV 心肌的对比增强模式。
选择 21 例经 2 名合格读者确定的正常冠状动脉 MDCT 血管造影的临床病例进行回顾性评估。使用 8 个相同大小和位置的 ROI，从 LV 心肌的短轴轴向重建中记录 HU 测量值，位于中间、心尖和基底位置。扫描在 320 层 MDCT 单元上进行。
中间短轴位置的外侧心肌壁（区域 2、3 和 4）的 HU 密度为 79.4（范围 42.3-162.7），低于下壁、间隔壁和前壁（区域 1、5、6、7 和 8）的 103.9（范围 11.4-159.6）（P<0.001）。基底切片外侧壁的 HU 密度为 82.3（范围 51.5-168.4），低于下壁、间隔壁和前壁的 94.9（范围 35.3-144）（P<0.001）。在心尖位置，外侧壁的 HU 密度为 79.9（范围 42.3-139.3），低于下壁、间隔壁和前壁的 100.9（范围 69.0-170.5）（P<0.001）。
在正常冠状动脉解剖的患者中，使用 320 层 MDCT 进行正常 LV 心肌增强显示，与前壁、间隔壁和下壁相比，外侧壁的密度明显较低。因此，在进行 CT 心肌灌注研究时应谨慎评估，以防止在 LV 外侧壁中误报这些较低的密度值。
