Hudsmith Lucy E, Petersen Steffen E, Tyler Damian J, Francis Jane M, Cheng Adrian S H, Clarke Kieran, Selvanayagam Joseph B, Robson Matthew D, Neubauer Stefan
University of Oxford Center for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK.
J Magn Reson Imaging. 2006 Aug;24(2):312-8. doi: 10.1002/jmri.20638.
To compare cardiac cine MR imaging using steady state free precession (SSFP) and fast low angle shot (FLASH) techniques at 1.5 and 3 T, and to establish their variabilities and reproducibilities for cardiac volume and mass determination in volunteers. To assess the feasibility of SSFP imaging in patients at 3 T and to determine comparability to volume data acquired at 1.5 T.
Ten healthy volunteers underwent cardiac magnetic resonance imaging using SSFP and segmented gradient-echo FLASH, using both a 1.5 and a 3 T MR system on the same day. Ten patients with impaired left ventricular (LV) function were also studied at both field strengths with SSFP.
For both SSFP and FLASH, field strength had no effect on the quantification of LV and right ventricular (RV) volumes, mass, or function (P > or = 0.05 for field strength for all parameters). At both 1.5 and 3 T, SSFP yielded smaller LV mass (e.g., at 3 T 109 +/- 30 g vs. 142 +/- 37 g; P = 0.011) and larger LV volume (e.g., at 3 T end-diastolic volume 149 +/- 37 mL vs. 133 +/- 31 mL at 5 T; P = 0.041) measurements than FLASH. In patients with reduced LV function, all volume and mass measurements were again similar for SSFP sequences at 1.5 vs. 3 T. In volunteers and patients, measurement variabilities for LV parameters were small for both field strength and sequences, ranging between 3.7% and 10.7% for mass.
Compared to 1.5 T, cardiac cine MR imaging at 3 T, using either FLASH or SSFP sequences, is feasible and highly reproducible. Field strength does not have an influence on quantification of cardiac volume or mass, but the systematic overestimation of LV mass and underestimation of LV volume by FLASH compared to SSFP is present at both 1.5 and 3 T. Normal values for cardiac volumes and mass established at 1.5 T can be applied to scans obtained at 3 T.
比较在1.5 T和3 T场强下使用稳态自由进动（SSFP）和快速小角度激发（FLASH）技术进行的心脏电影磁共振成像，确定其在志愿者心脏容积和质量测定中的变异性和可重复性。评估3 T场强下SSFP成像在患者中的可行性，并确定其与1.5 T场强下采集的容积数据的可比性。
10名健康志愿者在同一天使用1.5 T和3 T磁共振系统，分别采用SSFP和分段梯度回波FLASH序列进行心脏磁共振成像。10名左心室（LV）功能受损的患者也在这两种场强下采用SSFP序列进行研究。
对于SSFP和FLASH序列，场强对左心室和右心室（RV）容积、质量或功能的量化均无影响（所有参数的场强P值均≥0.05）。在1.5 T和3 T场强下，与FLASH序列相比，SSFP序列测得的左心室质量较小（如在3 T场强下为109±30 g，而FLASH序列为142±37 g；P = 0.011），左心室容积较大（如在3 T场强下舒张末期容积为149±37 mL，而在1.5 T场强下为133±31 mL；P = 0.041）。在左心室功能降低的患者中，1.5 T和3 T场强下SSFP序列的所有容积和质量测量结果再次相似。在志愿者和患者中，左心室参数的测量变异性对于场强和序列来说都较小，质量测量的变异性在3.7%至10.7%之间。
与1.5 T场强相比，在3 T场强下使用FLASH或SSFP序列进行心脏电影磁共振成像是可行且具有高度可重复性的。场强对心脏容积或质量的量化没有影响，但与SSFP序列相比，FLASH序列在1.5 T和3 T场强下均存在对左心室质量的系统性高估和对左心室容积的系统性低估。在1.5 T场强下建立的心脏容积和质量正常值可应用于3 T场强下获得的扫描图像。
