Estimation of myocardial strain from non-rigid registration and highly accelerated cine CMR.
Sparsely sampled cardiac cine accelerated acquisitions show promise for faster evaluation of left-ventricular function. Myocardial strain estimation using image feature tracking methods is also becoming widespread. However, it is not known whether highly accelerated acquisitions also provide reliable feature tracking strain estimates. Twenty patients and twenty healthy volunteers were imaged with conventional 14-beat/slice cine acquisition (STD), 4× accelerated 4-beat/slice acquisition with iterative reconstruction (R4), and a 9.2× accelerated 2-beat/slice real-time acquisition with sparse sampling and iterative reconstruction (R9.2). Radial and circumferential strains were calculated using non-rigid registration in the mid-ventricle short-axis slice and inter-observer errors were evaluated. Consistency was assessed using intra-class correlation coefficients (ICC) and bias with Bland-Altman analysis. Peak circumferential strain magnitude was highly consistent between STD and R4 and R9.2 (ICC = 0.876 and 0.884, respectively). Average bias was -1.7 ± 2.0 %, p < 0.001, for R4 and -2.7 ± 1.9 %, p < 0.001 for R9.2. Peak radial strain was also highly consistent (ICC = 0.829 and 0.785, respectively), with average bias -11.2 ± 18.4 %, p < 0.001, for R4 and -15.0 ± 21.2 %, p < 0.001 for R9.2. STD circumferential strain could be predicted by linear regression from R9.2 with an R2of 0.82 and a root mean squared error of 1.8 %. Similarly, radial strain could be predicted with an R2of 0.67 and a root mean squared error of 21.3 %. Inter-observer errors were not significantly different between methods, except for peak circumferential strain R9.2 (1.1 ± 1.9 %) versus STD (0.3 ± 1.0 %), p = 0.011. Although small systematic differences were observed in strain, these were highly consistent with standard acquisitions, suggesting that accelerated myocardial strain is feasible and reliable in patients who require short acquisition durations.
Department of Radiology, Auckland District Health Board, Auckland, New Zealand.
Jonathan E N
JE
Langton
Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand.
Hoi-Ieng
HI
Lam
Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand.
Brett R
BR
Cowan
Auckland District Health Board, Auckland, New Zealand.
Christopher J
CJ
Occleshaw
Auckland District Health Board, Auckland, New Zealand.
Ruvin
R
Gabriel
Auckland District Health Board, Auckland, New Zealand.
Boris
B
Lowe
Auckland District Health Board, Auckland, New Zealand.
Suzanne
S
Lydiard
Siemens Healthcare GmbH, Erlangen, Germany.
Andreas
A
Greiser
Siemens Healthcare GmbH, Erlangen, Germany.
Michaela
M
Schmidt
Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand. a.young@auckland.ac.nz.|Department of Anatomy with Radiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland, 1142, New Zealand. a.young@auckland.ac.nz.
Alistair A
http://orcid.org/0000-0001-5702-4220
AA
Young
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005240:Feasibility Studies; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D013997:Time Factors; D016277:Ventricular Function, Left
Iterative reconstruction; Non-rigid registration; Strain; Ventricular function