Department of Medicine, Cardiovascular Division, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA.
Magn Reson Med. 2011 Jul;66(1):180-6. doi: 10.1002/mrm.22769. Epub 2011 Feb 28.
Two-dimensional "pencil-beam" navigator, placed on the right hemidiaphragm, is used for free-breathing late gadolinium enhancement of the left atrium in patients with atrial fibrillation. The pencil-beam navigator creates an inflow artifact in the right pulmonary veins and atrial wall that may obscure local pulmonary vein and left atrium scars. To reduce this artifact, we propose a large slab right hemidiaphragm projection navigator that measures the respiratory motion while reducing the associated inflow artifact. Eighteen subjects underwent pulmonary vein late gadolinium enhancement using the pencil-beam and projection navigator. Subjective inflow and respiratory motion artifact scores (1 = severe, 2 = moderate, 3 = mild, and 4 = none) from two blinded readers were compared. The artifact scores were 3.8 ± 0.4 and 2.1 ± 0.7 for the projection and pencil-beam navigators, respectively (P < 0.001). Respiratory motion artifact scores were similar between the two techniques (3.0 ± 0.5 vs. 3.1 ± 0.5 for projection vs. pencil-beam navigator). The proposed method greatly reduces the inflow artifact in free-breathing pulmonary vein late gadolinium enhancement while allowing adequate respiratory motion compensation.
二维“铅笔束”导航仪置于右膈肌，用于房颤患者左心房自由呼吸晚期钆增强。铅笔束导航仪在右肺静脉和心房壁上产生流入伪影，可能会掩盖局部肺静脉和左心房疤痕。为了减少这种伪影，我们提出了一种大的右膈肌投影导航仪，可以在减少相关流入伪影的同时测量呼吸运动。18 名受试者使用铅笔束和投影导航仪进行了肺静脉晚期钆增强。两名盲法读者比较了主观流入和呼吸运动伪影评分（1=严重，2=中度，3=轻度，4=无）。投影和铅笔束导航仪的伪影评分为 3.8±0.4 和 2.1±0.7（P<0.001）。两种技术的呼吸运动伪影评分相似（投影导航仪为 3.0±0.5，铅笔束导航仪为 3.1±0.5）。该方法在允许充分呼吸运动补偿的同时，大大减少了自由呼吸肺静脉晚期钆增强中的流入伪影。
