Cardiovascular magnetic resonance by non contrast T1-mapping allows assessment of severity of injury in acute myocardial infarction.
BACKGROUND
Current cardiovascular magnetic resonance (CMR) methods, such as late gadolinium enhancement (LGE) and oedema imaging (T2W) used to depict myocardial ischemia, have limitations. Novel quantitative T1-mapping techniques have the potential to further characterize the components of ischemic injury. In patients with myocardial infarction (MI) we sought to investigate whether state-of the art pre-contrast T1-mapping (1) detects acute myocardial injury, (2) allows for quantification of the severity of damage when compared to standard techniques such as LGE and T2W, and (3) has the ability to predict long term functional recovery.


METHODS
3T CMR including T2W, T1-mapping and LGE was performed in 41 patients [of these, 78% were ST elevation MI (STEMI)] with acute MI at 12-48 hour after chest pain onset and at 6 months (6M). Patients with STEMI underwent primary PCI prior to CMR. Assessment of acute regional wall motion abnormalities, acute segmental damaged fraction by T2W and LGE and mean segmental T1 values was performed on matching short axis slices. LGE and improvement in regional wall motion at 6M were also obtained.


RESULTS
We found that the variability of T1 measurements was significantly lower compared to T2W and that, while the diagnostic performance of acute T1-mapping for detecting myocardial injury was at least as good as that of T2W-CMR in STEMI patients, it was superior to T2W imaging in NSTEMI. There was a significant relationship between the segmental damaged fraction assessed by either by LGE or T2W, and mean segmental T1 values (P < 0.01). The index of salvaged myocardium derived by acute T1-mapping and 6M LGE was not different to the one derived from T2W (P = 0.88). Furthermore, the likelihood of improvement of segmental function at 6M decreased progressively as acute T1 values increased (P < 0.0004).


CONCLUSIONS
In acute MI, pre-contrast T1-mapping allows assessment of the extent of myocardial damage. T1-mapping might become an important complementary technique to LGE and T2W for identification of reversible myocardial injury and prediction of functional recovery in acute MI.
Oxford Centre for Clinical Magnetic Resonance Research, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK. stefan.neubauer@cardiov.ox.ac.uk
Erica
E
Dall'Armellina
Stefan K
SK
Piechnik
Vanessa M
VM
Ferreira
Quang Le
QL
Si
Matthew D
MD
Robson
Jane M
JM
Francis
Florim
F
Cuculi
Rajesh K
RK
Kharbanda
Adrian P
AP
Banning
Robin P
RP
Choudhury
Theodoros D
TD
Karamitsos
Stefan
S
Neubauer
D000704:Analysis of Variance; D015906:Angioplasty, Balloon, Coronary; D016009:Chi-Square Distribution; D003287:Contrast Media; D004489:Edema, Cardiac / Q000175:diagnosis / Q000473:pathology; D004739:England; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D016015:Logistic Models; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D020127:Recovery of Function; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA