Myocardial T1: quantification by using an ECG-triggered radial single-shot inversion-recovery MR imaging sequence.
OBJECTIVE
To develop and validate a fast cardiac magnetic resonance imaging T1 mapping technique with high spatial resolution based on a radial inversion-recovery (IR) spoiled gradient-echo acquisition.


METHODS
Approval for the study was granted by the local institutional review board, and all subjects gave written informed consent. An electrocardiographically triggered radial single-shot IR (TRASSI) sequence was developed in conjunction with a custom-written fitting algorithm. The proposed imaging technique was validated in phantom measurements and then used for cardiac T1 mapping in 62 subjects with or without cardiac disease. The study population included 51 healthy subjects, three patients with arrhythmia, and eight patients with myocardial infarction. The potential heart rate dependency of the TRASSI method was tested by using linear regression analysis. Statistically significant differences between the sexes and various section orientations were analyzed with a Student t test for independent groups and a repeated-measures analysis of variance for dependent groups.


RESULTS
High-spatial-resolution T1 maps (1.17 × 1.17 mm) without motion artifacts and without heart rate dependency (slope = -0.0303, R(2) = 0.0000887, P = .899) were acquired with an acquisition time of less than 6 seconds in all subjects. The mean T1 of healthy left ventricular myocardium across all examined subjects was 1031 msec ± 33 (standard deviation). Testing for reproducibility in three individuals with 34 repetitive measurements revealed a mean standard deviation of 4.1 msec (0.412%). Subacute and chronic myocardial infarction could be detected in all eight patients. T1 disturbances due to arrhythmia proved to be minimal in three patients (standard deviation, <1.2%).


CONCLUSIONS
Fast and accurate cardiac T1 mapping is feasible within a single-shot IR experiment.
From the Research Center Magnetic-Resonance-Bavaria, Würzburg, Germany (D.G., P.M., F.F., P.M.J.); Department of Internal Medicine I-Cardiology, University Hospital Würzburg, Oberdürrbacher Str 6, 97080 Würzburg, Germany (D.G., O.R., W.R.B., G.E., P.N.); Comprehensive Heart Failure Center (O.R., W.R.B., G.E., P.N.) and Department of Experimental Physics 5 (P.M.J.), University of Würzburg, Würzburg, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany (H.H.Q.); Department of High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany (H.H.Q.); and Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany (M.E.L.).
Daniel
D
Gensler
Philipp
P
Mörchel
Florian
F
Fidler
Oliver
O
Ritter
Harald H
HH
Quick
Mark E
ME
Ladd
Wolfgang R
WR
Bauer
Georg
G
Ertl
Peter M
PM
Jakob
Peter
P
Nordbeck
D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis*; D057791:Cardiac Imaging Techniques / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D055815:Young Adult