Bohnen Sebastian, Radunski Ulf K, Lund Gunnar K, Tahir Enver, Avanesov Maxim, Stehning Christian, Schnackenburg Bernhard, Adam Gerhard, Blankenberg Stefan, Muellerleile Kai
University Medical Center Hamburg-Eppendorf, University Heart Center, General and Interventional Cardiology, Hamburg, Germany.
University Medical Center Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg, Germany.
Eur J Radiol. 2017 Jan;86:6-12. doi: 10.1016/j.ejrad.2016.10.031. Epub 2016 Oct 31.
T1 mapping is a promising diagnostic tool to improve the diagnostic accuracy of cardiovascular magnetic resonance (CMR) in patients with suspected myocarditis. However, there are currently no data on the potential influence of slice orientation on the diagnostic performance of CMR. Thus, we compared the diagnostic performance of global myocardial T1 and extracellular volume (ECV) values to differentiate patients with myocarditis from healthy individuals between different slice orientations.
This study included 48 patients with clinically defined myocarditis and 13 healthy controls who underwent CMR at 1.5T. A modified Look-Locker inversion-recovery (MOLLI) sequence was used for T1 mapping before and 15min after administration of 0.075mmol/kg Gadolinium-BOPTA. T1 mapping was performed on three short and on three long axes slices, respectively. Native T1, post-contrast T1 and extracellular volume (ECV) -BOPTA maps were calculated using a dedicated plug-in written for the OsiriX software and compared between the mean value of three short-axes slices (3SAX), the central short-axis (1SAX), the mean value of three long-axes slices (3LAX), the four-chamber view (4CH), the three-chamber view (3CH) and the two-chamber view (2CH).
There were significantly lower native T1 values on 3LAX (1081ms (1037-1131ms)) compared to 3SAX (1107ms (1069-1143ms), p=0.0022) in patients with myocarditis, but not in controls (1026ms (1009-1059ms) vs. 1039ms (1023-1055ms), p=0.2719). The areas under the curve (AUC) to discriminate between myocarditis and healthy controls by native myocardial T1 were 0.85 (p<0.0001) on 3SAX, 0.85 (p<0.0001) on 1SAX, 0.76 (p=0.0002) on 3LAX, 0.70 (p=0.0075) on 4CH, 0.72 (p=0.0020) on 3CH and 0.75 (p=0.0003) on 2CH. The AUCs for ECV-BOPTA were 0.83 (p<0.0001) on 3 SAX, 0.82 (p<0.0001) on 1SAX, 0.77 (p=0.0005) on 3LAX, 0.71 (p=0.0079) on 4CH, 0.69 (p=0.0371) on 3CH and 0.75 (p=0.0006) on 2CH.
Native T1 and ECV-BOPTA on short axes slices provide a better diagnostic performance in myocarditis than long axes slices since long axes slices seem to underestimate native myocardial T1 in myocarditis. T1 mapping in suspected myocarditis can be restricted to a single mid-ventricular short-axis slice without a significant loss in diagnostic performance.
T1映射是一种很有前景的诊断工具，可提高心血管磁共振成像（CMR）对疑似心肌炎患者的诊断准确性。然而，目前尚无关于切片方向对CMR诊断性能潜在影响的数据。因此，我们比较了整体心肌T1和细胞外容积（ECV）值在不同切片方向上区分心肌炎患者与健康个体的诊断性能。
本研究纳入了48例临床确诊的心肌炎患者和13名健康对照者，他们均接受了1.5T的CMR检查。在静脉注射0.075mmol/kg钆布醇前后，分别采用改良Look-Locker反转恢复（MOLLI）序列进行T1映射。T1映射分别在三个短轴切片和三个长轴切片上进行。使用为OsiriX软件编写的专用插件计算心肌T1、注射造影剂后的T1和细胞外容积（ECV）-钆布醇图，并比较三个短轴切片的平均值（3SAX）、中心短轴（1SAX）、三个长轴切片的平均值（3LAX）、四腔心切面（4CH）、三腔心切面（3CH）和两腔心切面（2CH）之间的差异。
心肌炎患者中，3LAX上的心肌T1值（1081ms（1037 - 1131ms））显著低于3SAX（1107ms（1069 - 1143ms），p = 0.0022），而在对照组中无此差异（1026ms（1009 - 1059ms）对1039ms（1023 - 1055ms），p = 0.2719）。通过心肌T1区分心肌炎患者与健康对照者的曲线下面积（AUC）在3SAX上为0.85（p < 0.0001），在1SAX上为0.85（p < 0.0001），在3LAX上为0.76（p = 0.0002），在4CH上为0.70（p = 0.0075），在3CH上为0.72（p = 0.0020），在2CH上为0.75（p = 0.0003）。ECV-钆布醇的AUC在3SAX上为0.83（p < 0.0001），在1SAX上为0.82（p < 0.0001），在3LAX上为0.77（p = 0.0005），在4CH上为0.71（p = 0.0079），在3CH上为0.69（p = 0.0371），在2CH上为0.75（p = 0.0006）。
短轴切片上的心肌T1和ECV-钆布醇在心肌炎诊断中比长轴切片具有更好的诊断性能，因为长轴切片似乎低估了心肌炎患者的心肌T1值。疑似心肌炎的T1映射可局限于单个心室中部短轴切片，而不会显著降低诊断性能。
