T-1 Mapping for the Diagnosis of Acute Myocarditis Using CMR Comparison to T-2-Weighted and Late Gadolinium Enhanced Imaging

Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
JACC. Cardiovascular imaging (Impact Factor: 7.19). 08/2013; 6(10). DOI: 10.1016/j.jcmg.2013.03.008
Source: PubMed


We sought to test the diagnostic performance of native T1 mapping in acute myocarditis compared with cardiac magnetic resonance (CMR) techniques such as dark-blood T2-weighted (T2W)-CMR, bright-blood T2W-CMR, and late gadolinium enhancement (LGE) imaging.
The diagnosis of acute myocarditis on CMR often requires multiple techniques, including T2W, early gadolinium enhancement, and LGE imaging. Novel techniques such as T1 mapping and bright-blood T2W-CMR are also sensitive to changes in free water content. We hypothesized that these techniques can serve as new and potentially superior diagnostic criteria for myocarditis.
We investigated 50 patients with suspected acute myocarditis (age 42 ± 16 years; 22% women) and 45 controls (age 42 ± 14 years; 22% women). CMR at 1.5-T (median 3 days from presentation) included: 1) dark-blood T2W-CMR (short-tau inversion recovery); 2) bright-blood T2W-CMR (acquisition for cardiac unified T2 edema); 3) native T1 mapping (shortened modified look-locker inversion recovery); and 4) LGE. Image analysis included: 1) global T2 signal intensity ratio of myocardium compared with skeletal muscle; 2) myocardial T1 relaxation times; and 3) areas of LGE.
Compared with controls, patients had significantly higher global T2 signal intensity ratios by dark-blood T2W-CMR (1.73 ± 0.27 vs. 1.56 ± 0.15, p < 0.01), bright-blood T2W-CMR (2.02 ± 0.33 vs. 1.84 ± 0.17, p < 0.01), and mean myocardial T1 (1,010 ± 65 ms vs. 941 ± 18 ms, p < 0.01). Receiver-operating characteristic analysis showed clear differences in diagnostic performance. The areas under the curve for each method were: T1 mapping (0.95), LGE (0.96), dark-blood T2 (0.78), and bright-blood T2 (0.76). A T1 cutoff of 990 ms had a sensitivity, specificity, and diagnostic accuracy of 90%, 91%, and 91%, respectively.
Native T1 mapping as a novel criterion for the detection of acute myocarditis showed excellent and superior diagnostic performance compared with T2W-CMR. It also has a higher sensitivity compared with T2W and LGE techniques, which may be especially useful in detecting subtle focal disease and when gadolinium contrast imaging is not feasible.

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Available from: Ntobeko Ntusi, Dec 23, 2013
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    • "Repeat analysis including all image artifacts showed preservation of all relative relationships and statistical significance (AUC of 0.92, 0.94 and 0.75, respectively). These results are closely comparable to our previous results using the same techniques in patients with suspected acute myocarditis [9]. The diagnostic performance of all individual and combination tissue criteria is presented in Table 2. "
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    ABSTRACT: Background Acute myocarditis can be diagnosed on cardiovascular magnetic resonance (CMR) using multiple techniques, including late gadolinium enhancement (LGE) imaging, which requires contrast administration. Native T1-mapping is significantly more sensitive than LGE and conventional T2-weighted (T2W) imaging in detecting myocarditis. The aims of this study were to demonstrate how to display the non-ischemic patterns of injury and to quantify myocardial involvement in acute myocarditis without the need for contrast agents, using topographic T1-maps and incremental T1 thresholds. Methods We studied 60 patients with suspected acute myocarditis (median 3 days from presentation) and 50 controls using CMR (1.5 T), including: (1) dark-blood T2W imaging; >(2) native T1-mapping (ShMOLLI); (3) LGE. Analysis included: (1) global myocardial T2 signal intensity (SI) ratio compared to skeletal muscle; (2) myocardial T1 times; (3) areas of injury by T2W, T1-mapping and LGE. Results Compared to controls, patients had more edema (global myocardial T2 SI ratio 1.71 ± 0.27 vs.1.56 ± 0.15), higher mean myocardial T1 (1011 ± 64 ms vs. 946 ± 23 ms) and more areas of injury as detected by T2W (median 5% vs. 0%), T1 (median 32% vs. 0.7%) and LGE (median 11% vs. 0%); all p < 0.001. A threshold of T1 > 990 ms (sensitivity 90%, specificity 88%) detected significantly larger areas of involvement than T2W and LGE imaging in patients, and additional areas of injury when T2W and LGE were negative. T1-mapping significantly improved the diagnostic confidence in an additional 30% of cases when at least one of the conventional methods (T2W, LGE) failed to identify any areas of abnormality. Using incremental thresholds, T1-mapping can display the non-ischemic patterns of injury typical of myocarditis. Conclusion Native T1-mapping can display the typical non-ischemic patterns in acute myocarditis, similar to LGE imaging but without the need for contrast agents. In addition, T1-mapping offers significant incremental diagnostic value, detecting additional areas of myocardial involvement beyond T2W and LGE imaging and identified extra cases when these conventional methods failed to identify abnormalities. In the future, it may be possible to perform gadolinium-free CMR using cine and T1-mapping for tissue characterization and may be particularly useful for patients in whom gadolinium contrast is contraindicated.
    Journal of Cardiovascular Magnetic Resonance 05/2014; 16(36). DOI:10.1186/1532-429X-16-36 · 4.56 Impact Factor
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    • "A single mid-ventricular short axis slice was acquired for postcontrast T1 maps at 1, 2, 3, 4, 8, 15 and 20 minutes after the administration of contrast (Gd-DOTA). Typical imaging parameters for the sequences used were as previously published [14]. "
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    ABSTRACT: Systemic sclerosis (SSc) is characterised by multi-organ tissue fibrosis including the myocardium. Diffuse myocardial fibrosis can be detected non-invasively by T1 and extracellular volume (ECV) quantification, while focal myocardial inflammation and fibrosis may be detected by T2-weighted and late gadolinium enhancement (LGE), respectively, using cardiovascular magnetic resonance (CMR). We hypothesised that multiparametric CMR can detect subclinical myocardial involvement in patients with SSc. 19 SSc patients (18 female, mean age 55 +/- 10 years) and 20 controls (19 female, mean age 56 +/- 8 years) without overt cardiovascular disease underwent CMR at 1.5T, including cine, tagging, T1-mapping, T2-weighted, LGE imaging and ECV quantification. Focal fibrosis on LGE was found in 10 SSc patients (53%) but none of controls. SSc patients also had areas of myocardial oedema on T2-weighted imaging (median 13 vs. 0% in controls). SSc patients had significantly higher native myocardial T1 values (1007 +/- 29 vs. 958 +/- 20 ms, p < 0.001), larger areas of myocardial involvement by native T1 >990 ms (median 52 vs. 3% in controls) and expansion of ECV (35.4 +/- 4.8 vs. 27.6 +/- 2.5%, p < 0.001), likely representing a combination of low-grade inflammation and diffuse myocardial fibrosis. Regardless of any regional fibrosis, native T1 and ECV were significantly elevated in SSc and correlated with disease activity and severity. Although biventricular size and global function were preserved, there was impairment in the peak systolic circumferential strain (-16.8 +/- 1.6 vs. -18.6 +/- 1.0, p < 0.001) and peak diastolic strain rate (83 +/- 26 vs. 114 +/- 16 s-1, p < 0.001) in SSc, which inversely correlated with diffuse myocardial fibrosis indices. Cardiac involvement is common in SSc even in the absence of cardiac symptoms, and includes chronic myocardial inflammation as well as focal and diffuse myocardial fibrosis. Myocardial abnormalities detected on CMR were associated with impaired strain parameters, as well as disease activity and severity in SSc patients. CMR may be useful in future in the study of treatments aimed at preventing or reducing adverse myocardial processes in SSc.
    Journal of Cardiovascular Magnetic Resonance 03/2014; 16(1):21. DOI:10.1186/1532-429X-16-21 · 4.56 Impact Factor
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    • "Native T1 changes are detectable in both acute and chronic MI [19,20], and may be used to characterize the edematous area at risk [21-23]. Elevated native T1 has also been reported in a number of diseases with cardiac involvement: myocarditis [24], amyloidosis [25], lupus [26], system capillary leakage syndrome [17], and decreases in native T1 have been associated with Anderson Fabry disease [27], and high iron content [28,29]. "
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    ABSTRACT: The longitudinal relaxation time constant (T1) of the myocardium is altered in various disease states due to increased water content or other changes to the local molecular environment. Changes in both native T1 and T1 following administration of gadolinium (Gd) based contrast agents are considered important biomarkers and multiple methods have been suggested for quantifying myocardial T1 in vivo. Characterization of the native T1 of myocardial tissue may be used to detect and assess various cardiomyopathies while measurement of T1 with extracellular Gd based contrast agents provides additional information about the extracellular volume (ECV) fraction. The latter is particularly valuable for more diffuse diseases that are more challenging to detect using conventional late gadolinium enhancement (LGE). Both T1 and ECV measures have been shown to have important prognostic significance. T1-mapping has the potential to detect and quantify diffuse fibrosis at an early stage provided that the measurements have adequate reproducibility. Inversion recovery methods such as MOLLI have excellent precision and are highly reproducible when using tightly controlled protocols. The MOLLI method is widely available and is relatively mature. The accuracy of inversion recovery techniques is affected significantly by magnetization transfer (MT). Despite this, the estimate of apparent T1 using inversion recovery is a sensitive measure, which has been demonstrated to be a useful tool in characterizing tissue and discriminating disease. Saturation recovery methods have the potential to provide a more accurate measurement of T1 that is less sensitive to MT as well as other factors. Saturation recovery techniques are, however, noisier and somewhat more artifact prone and have not demonstrated the same level of reproducibility at this point in time. This review article focuses on the technical aspects of key T1-mapping methods and imaging protocols and describes their limitations including the factors that influence their accuracy, precision, and reproducibility.
    Journal of Cardiovascular Magnetic Resonance 01/2014; 16(1):2. DOI:10.1186/1532-429X-16-2 · 4.56 Impact Factor
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