Strach K, Clauberg R, Müller A, Wonneberger U, Naehle C P, Kouwenhoven M, Gieseke J, Schild H H, Thomas D
Radiologische Universitätsklinik, Rheinische Friedrich-Wilhelms Universität Bonn, Sigmund-Freud-Strasse 25, Bonn, Germany.
Rofo. 2013 Jan;185(1):34-9. doi: 10.1055/s-0032-1325403. Epub 2012 Nov 5.
To investigate the feasibility of high-dose dobutamine stress (HDDS) imaging using SSFP sequences at 3 T employing patient-adaptive local RF-shimming using a dual-source RF transmission system.
13 Patients underwent a HDDS protocol on a 3 T MRI scanner (Achieva 3.0T-TX, Philips Healthcare), equipped with a dual-source RF transmission system. SSFP cine sequences using patient-adaptive local RF-shimming (RF-S) were compared to cine images acquired without additional shimming. Image quality was evaluated on a 4-point grading scale and number of non-diagnostic segments assessed. Contrast (CN) between myocardium (SIM) and blood pool (SIB) was calculated [(SIB-SIM)/(SIB+SIM)].
Image quality both at rest and maximum stress was significantly improved with RF-S (ED:3.56±0.5 vs. 3.23±0.63; ES:3.4±0.5 vs. 3.1±0.7) compared to no RF-S (ED:2.9±0.72 vs. 2.15±0.78; ES:2.64±0.74 vs. 1.95±0.76; p<0.01). The amount of non-diagnostic segments was significantly reduced when using RF-S at rest and stress (3 vs. 39; 19 vs. 78, p<0.05). All HDDS studies were diagnostic if performed with RF-S (n=13/13) in comparison to conventional shimming (n=5/13). Image contrast was improved for SSFP sequences with RF-S (0.53±0.08) compared to conventional images (0.46±0.09, p=0.06).
Patient-adaptive local RF-shimming using a dual-source RF transmission system allows for reliable SSFP imaging in a clinical high-dose dobutamine stress protocol at 3 T. RF-S significantly improves image quality and reduces the number of non-diagnostic myocardial segments.
探讨在3T磁共振成像系统中，使用双源射频传输系统进行患者自适应局部射频匀场，采用稳态自由进动序列（SSFP）进行大剂量多巴酚丁胺负荷（HDDS）成像的可行性。
13例患者在配备双源射频传输系统的3T磁共振成像扫描仪（Achieva 3.0T-TX，飞利浦医疗）上接受HDDS检查。将采用患者自适应局部射频匀场（RF-S）的SSFP电影序列与未进行额外匀场采集的电影图像进行比较。图像质量采用4分制评分，并评估非诊断节段的数量。计算心肌（SIM）与血池（SIB）之间的对比度（CN）[（SIB-SIM）/（SIB+SIM）]。
与未使用RF-S相比，使用RF-S时静息和最大负荷状态下的图像质量均显著提高（舒张末期：3.56±0.5对3.23±0.63；收缩末期：3.4±0.5对3.1±0.7）（舒张末期：2.9±0.72对2.15±0.78；收缩末期：2.64±0.74对1.95±0.76；p<0.01）。在静息和负荷状态下使用RF-S时，非诊断节段的数量显著减少（3对39；19对78，p<0.05）。与传统匀场相比，所有采用RF-S的HDDS检查均具有诊断价值（n=13/13），而传统匀场检查只有部分具有诊断价值（n=5/13）。与传统图像（0.46±0.09）相比，采用RF-S的SSFP序列的图像对比度有所提高（0.53±0.08，p=0.06）。
使用双源射频传输系统进行患者自适应局部射频匀场，可在3T临床大剂量多巴酚丁胺负荷检查中实现可靠的SSFP成像。RF-S显著提高了图像质量，减少了非诊断性心肌节段的数量。
