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Comparison of different cardiovascular magnetic resonance sequences for native myocardial T1 mapping at 3T.

ABSTRACT: BACKGROUND:T1 mapping based on cardiovascular magnetic resonance (CMR) is a novel approach using the magnetic relaxation T1 time as a quantitative marker for myocardial tissue composition. Various T1 mapping sequences are being used, with different strengths and weaknesses. Data comparing different sequences head to head however are sparse. METHODS:We compared three T1 mapping sequences, ShMOLLI, MOLLI and SASHA in phantoms and in a mid-ventricular slice of 40 healthy individuals (mean age 59?±?7 years, 45 % male) with low (68 %) or moderate cardiovascular risk. We calculated global and segmental T1 in vivo through exponential curve fitting and subsequent parametric mapping. We also analyzed image quality and inter-observer reproducibility. RESULTS:There was no association of T1 with cardiovascular risk groups. T1 however differed significantly depending on the sequence, with SASHA providing consistently higher mean values than ShMOLLI and MOLLI (1487?±?36 ms vs. 1174?±?37 ms and 1199?±?28 ms, respectively; p?

SUBMITTER: Teixeira T

PROVIDER: S-EPMC5050636 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Comparison of different cardiovascular magnetic resonance sequences for native myocardial T1 mapping at 3T.

Teixeira Tiago T Hafyane Tarik T Stikov Nikola N Akdeniz Cansu C Greiser Andreas A Friedrich Matthias G MG

Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance 20161004 1

<h4>Background</h4>T1 mapping based on cardiovascular magnetic resonance (CMR) is a novel approach using the magnetic relaxation T1 time as a quantitative marker for myocardial tissue composition. Various T1 mapping sequences are being used, with different strengths and weaknesses. Data comparing different sequences head to head however are sparse.<h4>Methods</h4>We compared three T1 mapping sequences, ShMOLLI, MOLLI and SASHA in phantoms and in a mid-ventricular slice of 40 healthy individuals ...[more]

PMID: 27716344

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Project description:BackgroundNative T1 may be a sensitive, contrast-free, non-invasive cardiovascular magnetic resonance (CMR) marker of myocardial tissue changes in patients with pulmonary artery hypertension. However, the diagnostic and prognostic value of native T1 mapping in this patient group has not been fully explored. The aim of this work was to determine whether elevation of native T1 in myocardial tissue in pulmonary hypertension: (a) varies according to pulmonary hypertension subtype; (b) has prognostic value and (c) is associated with ventricular function and interaction.MethodsData were retrospectively collected from a total of 490 consecutive patients during their clinical 1.5 T CMR assessment at a pulmonary hypertension referral centre in 2015. Three hundred sixty-nine patients had pulmonary hypertension [58?±?15 years; 66% female], an additional 39 had pulmonary hypertension due to left heart disease [68?±?13 years; 60% female], 82 patients did not have pulmonary hypertension [55?±?18; 68% female]. Twenty five healthy subjects were also recruited [58 ±4 years); 51% female]. T1 mapping was performed with a MOdified Look-Locker Inversion Recovery (MOLLI) sequence. T1 prognostic value in patients with pulmonary arterial hypertension was assessed using multivariate Cox proportional hazards regression analysis.ResultsPatients with pulmonary artery hypertension had elevated T1 in the right ventricular (RV) insertion point (pulmonary hypertension patients: T1?=?1060?±?90 ms; No pulmonary hypertension patients: T1?=?1020?±?80 ms p <?0.001; healthy subjects T1?=?940?±?50 ms p <?0.001) with no significant difference between the major pulmonary hypertension subtypes. The RV insertion point was the most successful T1 region for discriminating patients with pulmonary hypertension from healthy subjects (area under the curve?=?0.863) however it could not accurately discriminate between patients with and without pulmonary hypertension (area under the curve?=?0.654). T1 metrics did not contribute to prediction of overall mortality (septal: p =?0.552; RV insertion point: p =?0.688; left ventricular free wall: p =?0.258). Systolic interventricular septal angle was a significant predictor of T1 in patients with pulmonary hypertension (p <?0.001).ConclusionsElevated myocardial native T1 was found to a similar extent in pulmonary hypertension patient subgroups and is independently associated with increased interventricular septal angle. Native T1 mapping may not be of additive value in the diagnostic or prognostic evaluation of patients with pulmonary artery hypertension.

Project description:BackgroundPreclinical studies and pilot patient studies have shown that chronic infarctions can be detected and characterized from cardiac magnetic resonance without gadolinium-based contrast agents using native-T1 maps at 3T. We aimed to investigate the diagnostic capacity of this approach for characterizing chronic myocardial infarctions (MIs) in a multi-center setting.MethodsPatients with a prior MI (n=105) were recruited at 3 different medical centers and were imaged with native-T1 mapping and late gadolinium enhancement (LGE) at 3T. Infarct location, size, and transmurality were determined from native-T1 maps and LGE. Sensitivity, specificity, receiver-operating characteristic metrics, and inter- and intraobserver variabilities were assessed relative to LGE.ResultsAcross all subjects, T1 of MI territory was 1621±110 ms, and remote territory was 1225±75 ms. Sensitivity, specificity, and area under curve for detecting MI location based on native-T1 mapping relative to LGE were 88%, 92%, and 0.93, respectively. Native-T1 maps were not different for measuring infarct size (native-T1 maps: 12.1±7.5%; LGE: 11.8±7.2%, P=0.82) and were in agreement with LGE (R2=0.92, bias, 0.09±2.6%). Corresponding inter- and intraobserver assessments were also highly correlated (interobserver: R2=0.90, bias, 0.18±2.4%; and intraobserver: R2=0.91, bias, 0.28±2.1%). Native T1 maps were not different for measuring MI transmurality (native-T1 maps: 49.1±15.8%; LGE: 47.2±19.0%, P=0.56) and showed agreement (R2=0.71; bias, 1.32±10.2%). Corresponding inter- and intraobserver assessments were also in agreement (interobserver: R2=0.81, bias, 0.1±9.4%; and intraobserver: R2=0.91, bias, 0.28±2.1%, respectively). While the overall accuracy for detecting MI with native-T1 maps at 3T was high, logistic regression analysis showed that MI location was a prominent confounder.ConclusionsNative-T1 mapping can be used to image chronic MI with high degree of accuracy, and as such, it is a viable alternative for scar imaging in patients with chronic MI who are contraindicated for LGE. Technical advancements may be needed to overcome the imaging confounders that currently limit native-T1 mapping from reaching equivalent detection levels as LGE.

Project description:BACKGROUND:Myocardial recovery after primary percutaneous coronary intervention in acute myocardial infarction is variable and the extent and severity of injury are difficult to predict. We sought to investigate the role of cardiovascular magnetic resonance T1 mapping in the determination of myocardial injury very early after treatment of ST-segment elevation myocardial infarction (STEMI). METHODS:STEMI patients underwent 3?T cardiovascular magnetic resonance (CMR), within 3?h of primary percutaneous intervention (PPCI). T1 mapping determined the extent (area-at-risk as %left ventricle, AAR) and severity (average T1 values of AAR) of acute myocardial injury, and related these to late gadolinium enhancement (LGE), and microvascular obstruction (MVO). The characteristics of myocardial injury within 3?h was compared with changes at 24-h to predict final infarct size. RESULTS:Forty patients were included in this study. Patients with average T1 values of AAR ?1400?ms within 3?h of PPCI had larger LGE at 24-h (33% ±14 vs. 18% ±10, P?=?0.003) and at 6-months (27% ±9 vs. 12% ±9; P?<?0.001), higher incidence and larger extent of MVO (85% vs. 40%, P?=?0.016) & [4.0 (0.5-9.5)% vs. 0 (0-3.0)%, P?=?0.025]. The average T1 value was an independent predictor of acute LGE (? 0.61, 95%CI 0.13 to 1.09; P?=?0.015), extent of MVO (? 0.22, 95%CI 0.03 to 0.41, P?=?0.028) and final infarct size (? 0.63, 95%CI 0.21 to 1.05; P?=?0.005). Receiver-operating-characteristic analysis showed that T1 value of AAR obtained within 3-h, but not at 24-h, predicted large infarct size (LGE >?9.5%) with 100% positive predictive value at the optimal cut-off of 1400?ms (area-under-the-curve, AUC 0.88, P?=?0.006). CONCLUSION:Hyper-acute T1 values of the AAR (within 3?h post PPCI, but not 24?h) predict a larger extent of MVO and infarct size at both 24?h and 6?months follow-up. Delayed CMR scanning for 24?h could not substitute the significant value of hyper-acute average T1 in determining infarct characteristics.

Project description: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.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.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).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.

Dataset Information

Comparison of different cardiovascular magnetic resonance sequences for native myocardial T1 mapping at 3T.

Publications

Comparison of different cardiovascular magnetic resonance sequences for native myocardial T1 mapping at 3T.

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