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T1 mapping: characterisation of myocardial interstitial space.

Perea RJ, Ortiz-Perez JT, Sole M, Cibeira MT, de Caralt TM, Prat-Gonzalez S, Bosch X, Berruezo A, Sanchez M, Blade J - Insights Imaging (2014)

Bottom Line: Myocardial fibrosis is always present in end-stage heart failure and is a major independent predictor of adverse cardiac outcome.T1 mapping techniques performed both with and without contrast enable the quantification of diffuse myocardial fibrosis and myocardial infiltration.This article reviews current imaging techniques, emerging applications and the future potential and limitations of CMR for T1 mapping. • Myocardial fibrosis is a common endpoint in a variety of cardiac diseases. • Myocardial fibrosis results in myocardial stiffness, heart failure, arrhythmia and sudden death. • T1-mapping CMR techniques enable the quantification of diffuse myocardial fibrosis. • Native T1 reflects myocardial disease involving the myocyte and interstitium. • The use of gadolinium allows measurement of the extracellular volume fraction, reflecting interstitial space.

View Article: PubMed Central - PubMed

Affiliation: Radiology Department. Hospital Clinic, University of Barcelona, Barcelona, Spain, rjperea@clinic.ub.es.

ABSTRACT

Unlabelled: Myocardial fibrosis is always present in end-stage heart failure and is a major independent predictor of adverse cardiac outcome. Cardiac magnetic resonance (CMR) is an imaging method that permits a non-invasive assessment of the heart and has been established as the "gold standard" for the evaluation of cardiac anatomy and function, as well as for quantifying focal myocardial fibrosis in both ischaemic and non-ischaemic heart disease. However, cardiac pathologies characterised by diffuse myocardial fibrosis cannot be evaluated by late gadolinium enhancement (LGE) imaging, as there are no reference regions of normal myocardium. Recent improvements in CMR imaging techniques have enabled parametric mapping of relaxation properties (T1, T2 and T2*) clinically feasible within a single breath-hold. T1 mapping techniques performed both with and without contrast enable the quantification of diffuse myocardial fibrosis and myocardial infiltration. This article reviews current imaging techniques, emerging applications and the future potential and limitations of CMR for T1 mapping.

Teaching points: • Myocardial fibrosis is a common endpoint in a variety of cardiac diseases. • Myocardial fibrosis results in myocardial stiffness, heart failure, arrhythmia and sudden death. • T1-mapping CMR techniques enable the quantification of diffuse myocardial fibrosis. • Native T1 reflects myocardial disease involving the myocyte and interstitium. • The use of gadolinium allows measurement of the extracellular volume fraction, reflecting interstitial space.

No MeSH data available.


Related in: MedlinePlus

T1 mapping in acute myocardial infarction. Subendocardial enhancement (a) in the inferolateral, midventricular segment of the left ventricle. Although the T2-weighted images (b) show only a mild increase in brightness (long arrows), there is an area of increased T1 values (1,208 ms, into the orange range of the colour scale) (short arrows) (c) exceeding the area of LGE enhancement
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Fig11: T1 mapping in acute myocardial infarction. Subendocardial enhancement (a) in the inferolateral, midventricular segment of the left ventricle. Although the T2-weighted images (b) show only a mild increase in brightness (long arrows), there is an area of increased T1 values (1,208 ms, into the orange range of the colour scale) (short arrows) (c) exceeding the area of LGE enhancement

Mentions: Native T1 distinguishes normal from abnormal myocardium, indicating myocardial disease involving both the myocyte and interstitium. Measurement requires no exogenous contrast administration, making it feasible in patients with severe renal dysfunction or pregnancy. Cardiac T1-mapping without the use of a GBCA has been shown to be sensitive to a variety of pathologies where increased water is present, such as oedema [63, 64], focal or diffuse fibrosis [65] and amyloidosis [66]. Acute myocardial injury is accompanied by intracellular and interstitial oedema and is traditionally detected by increased T2 signal, although pre-contrast T1 mapping may prove to be equally effective and robust [64]. The oedema in myocardial ischaemia and infarction can be recognised by increases in T1 with high sensitivity and specificity [67, 68, 69] (Fig. 11). In chronic myocardial infarction, there is replacement of myocardial cells by fibrosis with an increase in extracellular collagen. Consequently, T1 values are higher than in normal myocardium, but not as high as in acute myocardial infarction [67]. For determining the area at risk, native T1 and T2 mapping provide similar results and closely match the area at risk as defined by microspheres in animal models [64]. Native T1 mapping is superior compared with T2-weighted and LGE techniques in detecting acute myocarditis [70, 71], which is helpful in subtle focal disease [72] and may detect pathology missed by LGE technique, such as pan-myocarditis [72]. Native T1 values provide diagnostic accuracy to discriminate between normal and diffuse fibrosis in patients with non-ischaemic dilated cardiomyopathies [73, 74] and hypertrophic cardiomyopathy [73, 74], having the potential to become a test in patients with suspected diffuse fibrosis, which may be missed by classic LGE imaging. Furthermore, native T1 is significantly elevated in patients with aortic stenosis and correlates with the CVF quantified at biopsy [65]. Diffuse fibrosis is an important clinical parameter in aortic stenosis and is also reflected in the degree of postoperative recovery. However, fibrosis is a potentially reversible phenomenon under several therapies [75]. Cardiac amyloidosis shows markedly increased non-contrast T1 relaxation times in the myocardium [66, 76], even more pronounced that in aortic stenosis [66] (Fig. 12). Myocardial T1 mapping is an accurate technique for the detection of cardiac involvement in amyloidosis, avoiding the administration of GBCA that frequently is problematic in this group of patients [66]. Other pathologies may result in a decrease of native T1 values, like Anderson-Fabry disease, because of the intracellular lipid accumulation [77], and iron overload where T1 mapping is superior to the classic T2* sequence for the detection of early iron overload [78].Fig. 11


T1 mapping: characterisation of myocardial interstitial space.

Perea RJ, Ortiz-Perez JT, Sole M, Cibeira MT, de Caralt TM, Prat-Gonzalez S, Bosch X, Berruezo A, Sanchez M, Blade J - Insights Imaging (2014)

T1 mapping in acute myocardial infarction. Subendocardial enhancement (a) in the inferolateral, midventricular segment of the left ventricle. Although the T2-weighted images (b) show only a mild increase in brightness (long arrows), there is an area of increased T1 values (1,208 ms, into the orange range of the colour scale) (short arrows) (c) exceeding the area of LGE enhancement
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4376813&req=5

Fig11: T1 mapping in acute myocardial infarction. Subendocardial enhancement (a) in the inferolateral, midventricular segment of the left ventricle. Although the T2-weighted images (b) show only a mild increase in brightness (long arrows), there is an area of increased T1 values (1,208 ms, into the orange range of the colour scale) (short arrows) (c) exceeding the area of LGE enhancement
Mentions: Native T1 distinguishes normal from abnormal myocardium, indicating myocardial disease involving both the myocyte and interstitium. Measurement requires no exogenous contrast administration, making it feasible in patients with severe renal dysfunction or pregnancy. Cardiac T1-mapping without the use of a GBCA has been shown to be sensitive to a variety of pathologies where increased water is present, such as oedema [63, 64], focal or diffuse fibrosis [65] and amyloidosis [66]. Acute myocardial injury is accompanied by intracellular and interstitial oedema and is traditionally detected by increased T2 signal, although pre-contrast T1 mapping may prove to be equally effective and robust [64]. The oedema in myocardial ischaemia and infarction can be recognised by increases in T1 with high sensitivity and specificity [67, 68, 69] (Fig. 11). In chronic myocardial infarction, there is replacement of myocardial cells by fibrosis with an increase in extracellular collagen. Consequently, T1 values are higher than in normal myocardium, but not as high as in acute myocardial infarction [67]. For determining the area at risk, native T1 and T2 mapping provide similar results and closely match the area at risk as defined by microspheres in animal models [64]. Native T1 mapping is superior compared with T2-weighted and LGE techniques in detecting acute myocarditis [70, 71], which is helpful in subtle focal disease [72] and may detect pathology missed by LGE technique, such as pan-myocarditis [72]. Native T1 values provide diagnostic accuracy to discriminate between normal and diffuse fibrosis in patients with non-ischaemic dilated cardiomyopathies [73, 74] and hypertrophic cardiomyopathy [73, 74], having the potential to become a test in patients with suspected diffuse fibrosis, which may be missed by classic LGE imaging. Furthermore, native T1 is significantly elevated in patients with aortic stenosis and correlates with the CVF quantified at biopsy [65]. Diffuse fibrosis is an important clinical parameter in aortic stenosis and is also reflected in the degree of postoperative recovery. However, fibrosis is a potentially reversible phenomenon under several therapies [75]. Cardiac amyloidosis shows markedly increased non-contrast T1 relaxation times in the myocardium [66, 76], even more pronounced that in aortic stenosis [66] (Fig. 12). Myocardial T1 mapping is an accurate technique for the detection of cardiac involvement in amyloidosis, avoiding the administration of GBCA that frequently is problematic in this group of patients [66]. Other pathologies may result in a decrease of native T1 values, like Anderson-Fabry disease, because of the intracellular lipid accumulation [77], and iron overload where T1 mapping is superior to the classic T2* sequence for the detection of early iron overload [78].Fig. 11

Bottom Line: Myocardial fibrosis is always present in end-stage heart failure and is a major independent predictor of adverse cardiac outcome.T1 mapping techniques performed both with and without contrast enable the quantification of diffuse myocardial fibrosis and myocardial infiltration.This article reviews current imaging techniques, emerging applications and the future potential and limitations of CMR for T1 mapping. • Myocardial fibrosis is a common endpoint in a variety of cardiac diseases. • Myocardial fibrosis results in myocardial stiffness, heart failure, arrhythmia and sudden death. • T1-mapping CMR techniques enable the quantification of diffuse myocardial fibrosis. • Native T1 reflects myocardial disease involving the myocyte and interstitium. • The use of gadolinium allows measurement of the extracellular volume fraction, reflecting interstitial space.

View Article: PubMed Central - PubMed

Affiliation: Radiology Department. Hospital Clinic, University of Barcelona, Barcelona, Spain, rjperea@clinic.ub.es.

ABSTRACT

Unlabelled: Myocardial fibrosis is always present in end-stage heart failure and is a major independent predictor of adverse cardiac outcome. Cardiac magnetic resonance (CMR) is an imaging method that permits a non-invasive assessment of the heart and has been established as the "gold standard" for the evaluation of cardiac anatomy and function, as well as for quantifying focal myocardial fibrosis in both ischaemic and non-ischaemic heart disease. However, cardiac pathologies characterised by diffuse myocardial fibrosis cannot be evaluated by late gadolinium enhancement (LGE) imaging, as there are no reference regions of normal myocardium. Recent improvements in CMR imaging techniques have enabled parametric mapping of relaxation properties (T1, T2 and T2*) clinically feasible within a single breath-hold. T1 mapping techniques performed both with and without contrast enable the quantification of diffuse myocardial fibrosis and myocardial infiltration. This article reviews current imaging techniques, emerging applications and the future potential and limitations of CMR for T1 mapping.

Teaching points: • Myocardial fibrosis is a common endpoint in a variety of cardiac diseases. • Myocardial fibrosis results in myocardial stiffness, heart failure, arrhythmia and sudden death. • T1-mapping CMR techniques enable the quantification of diffuse myocardial fibrosis. • Native T1 reflects myocardial disease involving the myocyte and interstitium. • The use of gadolinium allows measurement of the extracellular volume fraction, reflecting interstitial space.

No MeSH data available.


Related in: MedlinePlus