Human heart: tagging with MR imaging--a method for noninvasive assessment of myocardial motion.

PurposeTo assess myocardial strain using cine displacement encoding with stimulated echoes (DENSE) using 1.5T and 3.0T MRI in healthy adults.Materials and MethodsHealthy adults without any history of cardiovascular disease underwent magnetic resonance imaging (MRI) at 1.5T and 3.0T within 2 days. The MRI protocol included balanced steady‐state free‐precession (b‐SSFP), 2D cine‐echo planar imaging (EPI)‐DENSE, and late gadolinium enhancement in subjects >45 years. Acquisitions were divided into six segments; global and segmental peak longitudinal and circumferential strain were derived and analyzed by field strength, age, and gender.ResultsIn all, 89 volunteers (mean age 44.8 ± 18.0 years, range: 18–87 years) underwent MRI at 1.5T, and 88 of these subjects underwent MRI at 3.0T (1.4 ± 1.4 days between the scans). Compared with 3.0T, the magnitudes of global circumferential (–19.5 ± 2.6% vs. –18.47 ± 2.6%; P = 0.001) and longitudinal (–12.47 ± 3.2% vs. –10.53 ± 3.1%; P = 0.004) strain were greater at 1.5T. At 1.5T, longitudinal strain was greater in females than in males: –10.17 ± 3.4% vs. –13.67 ± 2.4%; P = 0.001. Similar observations occurred for circumferential strain at 1.5T (–18.72 ± 2.2% vs. –20.10 ± 2.7%; P = 0.014) and at 3.0T (–17.92 ± 1.8% vs. –19.1 ± 3.1%; P = 0.047). At 1.5T, longitudinal and circumferential strain were not associated with age after accounting for sex (longitudinal strain P = 0.178, circumferential strain P = 0.733). At 3.0T, longitudinal and circumferential strain were associated with age (P < 0.05). Longitudinal strain values were greater in the apico‐septal, basal‐lateral, and mid‐lateral segments and circumferential strain in the inferior, infero‐lateral, and antero‐lateral LV segments.ConclusionMyocardial strain parameters as revealed by cine‐DENSE at different MRI field strengths were associated with myocardial region, age, and sex. J. Magn. Reson. Imaging 2016;44:1197–1205.

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Myocardial strain in healthy adults across a broad age range as revealed by cardiac magnetic resonance imaging at 1.5 and 3.0T: Associations of myocardial strain with myocardial region, age, and sex

Mangion

Clerfond

McComb

et al. 2016

“…The one-dimensional constraints from all directions can be stacked to form the matrix equation (cf, ref. 9) [1] Y is a vector containing the one-dimensional displacements, E is a matrix containing the undeformed tag plane normals, U is a vector containing all of the three-dimensional displacement vectors to be estimated in a given time frame, and W is a zero mean noise vector with covariance matrix , which models any errors in the tag line tracking algorithm. Small values of , correspond to small errors in tag tracking.…”

Section: Spatial Coordinate Displacement Fitmentioning

confidence: 99%

Model‐free reconstruction of three‐dimensional myocardial strain from planar tagged MR images

Denney

McVeigh

1997

A technique is presented for reconstructing a three-dimensional myocardial strain map from a set of parallel-tagged MR images. Radial strains were reconstructed from in vivo data from an anesthetized dog with values between .05 and .1 with a precision of ± .003 for a tag detection accuracy of .1 mm and a tag spacing of 2.5 mm. The reconstruction spatial resolution was demonstrated by reconstructing a localized displacement abnormality. In the circumferential direction, the abnormality that resulted in 5O% displacement attenuation had a full width at half maximum of 5.4 ± .4 mm (mean ± SD). Graphs are presented showing the relationship between the size of an abnormality and the ability of the method to reconstruct that abnormality. The combination of high resolution parallel-tagged MR images and the model-free, coordinate system-free strain reconstruction technique presented in this paper is capable of producing accurate, high resolution strain maps of the myocardium. KeywordsCardiac MRI; Left ventricle; Cardiac mechanics; Spatial resolution Recent developments in MR tagging (1-9) make it possible to noninvasively measure the threedimensional motion of the heart wall. In tagged images, the myocardium appears with a spatially encoded pattern that moves with the tissue and can be analyzed to reconstruct the motion of the myocardium and measures of local contractile performance such as strain. Precise, quantitative measurements of myocardial function (strain) may allow clinicians to detect ischemia during stress testing with lower doses of inotropic agents. Also, the detection of functional recovery in stunned myocardium during low dose dobutamine infusion may be used to detect viable myocardium (10)(11)(12)(13)(14); this requires a technique that is very sensitive to small changes in myocardial strain. In this paper, we present a method for reconstructing a three-dimensional strain field of the left ventricle (LV) from a collection of tagged MR images.O'Dell et al (8) presented a three-dimensional strain reconstruction algorithm based on a prolate spheroidal basis function displacement model. This approach produces excellent results at the midwall, but careful preprocessing is required to get the heart in the correct coordinate system for reconstruction because the coordinate system foci and axes are critical to the reconstruction accuracy. Young et al (7,15) and Moulton et al (16) have developed three-dimensional strain reconstruction schemes based on a 16-element mesh and a piece-wise polynomial displacementCorrespondence to: Thomas S. Denney, Jr.. In this paper, we present a new model-free algorithm for reconstructing three-dimensional strain based on the discrete approach of Denney and Prince (9). The discrete model-free (DMF) algorithm decomposes the myocardial volume into a finely spaced mesh of points and reconstructs a high resolution three-dimensional displacement field using finite difference analysis and a smoothness constraint that minimizes the spatial variation of displacement across the myoc...

“…In addition, quantifying degrees of function during stress testing or degrees of contraction asynchrony for predicting the response to cardiac resynchronization therapy can be performed (6,7). Currently, for cardiovascular magnetic resonance (CMR), MR tagging is widely used to measure myocardial strain (8,9). However, this method has some disadvantages, such as limited temporal resolution and the need for sophisticated and time-consuming methods for image processing.…”

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confidence: 99%

Strain‐encoded (SENC) magnetic resonance imaging to evaluate regional heterogeneity of myocardial strain in healthy volunteers: Comparison with conventional tagging

Neizel

Loßnitzer

Korosoglou

et al. 2008

Purpose:To evaluate the ability of strain-encoded (SENC) magnetic resonance imaging (MRI) for regional systolic and diastolic strain analysis of the myocardium in healthy volunteers. Materials and Methods:Circumferential and longitudinal peak systolic strain values of 75 healthy volunteers (35 women and 40 men, mean age 44 Ϯ 12 years) were measured using SENC at 1.5T. MR tagging was used as the reference standard for measuring regional function. Diastolic function was assessed in the 10 youngest (24 Ϯ 8 years) and 10 oldest (62 Ϯ 5 years) subjects. Results:Peak strain values assessed with SENC were comparable to those obtained by MR tagging, showing narrow limits of agreement (limits of agreement -5.6% to 8.1%). Regional heterogeneity was observed between different segments of the left ventricle (LV) by both techniques (P Ͻ 0.001). Longitudinal strain obtained by SENC was also heterogenous (P Ͻ 0.001). Interestingly, no age-or genderspecific differences in peak systolic strain were observed, whereas the peak rate of relaxation of circumferential strain rate was decreased in the older group.Conclusion SENC is a reliable tool for accurate and objective quantification of regional myocardial systolic as well as diastolic function. In agreement with tagged MRI, SENC detected slightly heterogeneous myocardial strain within LV segments.