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Background: In acute myocardial infarction (AMI), both tissue necrosis and edema are present and both might be implicated in the development of intraventricular dyssynchrony. However, their relative contribution to transient dyssynchrony is not known. Cardiovascular magnetic resonance (CMR) can detect necrosis and edema with high spatial resolution and it can quantify dyssynchrony by tagging techniques., Methods: Patients with a first AMI underwent percutaneous coronary interventions (PCI) of the infarct-related artery within 24 h of onset of chest pain. Within 5-7 days after the event and at 4 months, CMR was performed. The CMR protocol included the evaluation of intraventricular dyssynchrony by applying a novel 3D-tagging sequence to the left ventricle (LV) yielding the CURE index (circumferential uniformity ratio estimate; 1 = complete synchrony). On T2-weighted images, edema was measured as high-signal (> 2 SD above remote tissue) along the LV mid-myocardial circumference on 3 short-axis images (% of circumference corresponding to the area-at-risk). In analogy, on late-gadolinium enhancement (LGE) images, necrosis was quantified manually as percentage of LV mid-myocardial circumference on 3 short-axis images. Necrosis was also quantified on LGE images covering the entire LV (expressed as % LV mass). Finally, salvaged myocardium was calculated as the area-at-risk minus necrosis (expressed as % of LV circumference)., Results: After successful PCI (n = 22, 2 female, mean age: 57 ± 12y), peak troponin T was 20 ± 36ug/l and the LV ejection fraction on CMR was 41 ± 8%. Necrosis mass was 30 ± 10% and CURE was 0.91 ± 0.05. Edema was measured as 58 ± 14% of the LV circumference. In the acute phase, the extent of edema correlated with dyssynchrony (r2 = -0.63, p < 0.01), while extent of necrosis showed borderline correlation (r2 = -0.19, p = 0.05). PCI resulted in salvaged myocardium of 27 ± 14%. LV dyssynchrony (=CURE) decreased at 4 months from 0.91 ± 0.05 to 0.94 ± 0.03 (p < 0.004, paired t-test). At 4 months, edema was absent and scar %LV slightly shrunk to 23.7 ± 10.0% (p < 0.002 vs baseline). Regression of LV dyssynchrony during the 4 months follow-up period was predicted by both, the extent of edema and its necrosis component in the acute phase., Conclusions: In the acute phase of infarction, LV dyssynchrony is closely related to the extent of edema, while necrosis is a poor predictor of acute LV dyssynchrony. Conversely, regression of intraventricular LV dyssynchrony during infarct healing is predicted by the extent of necrosis in the acute phase.

Aims: To quantify left ventricular (LV) dyssynchrony in patients with left bundle branch block (LBBB) and in patients after myocardial infarction (MI) applying an accelerated three-dimensional (3D) tagging cardiac magnetic resonance (CMR) technique, and to combine dyssynchrony information with viability data obtained by late gadolinium enhancement (LGE) CMR., Methods and Results: Thirty-two patients (59 +/- 11 years) after first MI (Pats(MI)), 10 patients (63 +/- 10 years) with LBBB (ejection fraction < 40%; Pats(LBBB<40)), 13 patients (63 +/- 11) with LBBB (ejection fraction >or= 40%; Pats(LBBB >or=40 )), and 15 healthy controls (53 +/- 10 years) underwent 3D tagging CMR and LGE imaging at 1.5 T. As a measure of mechanical LV dyssynchrony, the standard deviation of T(max) over the LV, the circumferential uniformity ratio estimate (CURE) index, and a segmental-based circumferential systolic dyssynchrony index (SDI) were calculated. All three parameters detected significantly increased circumferential dyssynchrony in patients compared with controls. The CURE and SDI showed a good correlation (r = 0.93, P < 0.0001) and detected most severe dyssynchrony in Pats(LBBB<40) (P < 0.001 vs. controls, P < 0.005 vs. Pats(MI)). Systolic dyssynchrony index additionally allowed integration of localized viability information to yield SDI(viable) which was highest in Pats(LBBB<40)., Conclusion: Dyssynchrony patterns in the LV can be quantified globally and regionally by 3D tagging CMR. Combination of viability and dyssynchrony information allows for a comprehensive dyssynchrony quantification in patients with LBBB or post-MI. Future studies are required to test the value of the method to predict responsiveness to resynchronization.

Pulsatile brain motion is considered to be an important mechanical link between blood and cerebrospinal fluid (CSF) dynamics. Like many severe brain diseases, different types of hydrocephalus are associated with impairment of these dynamics. In this work a cine displacement-encoded imaging method employing stimulated echoes (DENSE) and a three-dimensional (3D) segmented echo-planar imaging (EPI) readout for brain motion measurements in all three spatial directions is presented. Displacement-encoded data sets of 12 healthy volunteers were analyzed with respect to reproducibility, periodicity, and intra- as well as intersubject physiological consistency. In addition, displacement values were compared with data derived from phase-contrast (PC) velocity measurements in a subset of all measured subjects. Using DENSE, displacements as low as 0.01 mm could be detected and observation of the 3D pulse pressure wave propagation was possible. Among other parameters, peak displacements in the central brain regions were measured: feet-head (FH): thalamus (0.13 +/- 0.01 mm); right-left (RL): thalamus (0.06 +/- 0.01 mm); and anterior-posterior (AP): caudate nucleus (0.05 +/- 0.01 mm).

Myocardial tissue tagging using complementary spatial modulation of magnetization (CSPAMM) allows detailed assessment of myocardial motion. To capture the complex 3D cardiac motion pattern, multiple 2D tagged slices are usually acquired in different orientations. These approaches are prone to slice misregistration and associated with long acquisition times. In this work, a fast method for acquiring 3D CSPAMM data is proposed that allows measuring deformation of the whole heart in three breath-holds of 18 heartbeats duration each. Three acquisitions are sequentially performed with line tag preparation in each orthogonal direction. Measurement acceleration is achieved by applying localized tagging preparation and a hybrid multishot, segmented echo-planar imaging sequence. Five healthy volunteers and five patients with myocardial infarction were measured. Midwall contours were tracked throughout the cardiac cycle with an enhanced variant of the harmonic phase (HARP) technique. Circumferential shortening at end-systole ranged from 14.1% (base) to 20.1% (apex) in healthy subjects. Hypokinetic regions in patients corresponded well with regions exhibiting hyperenhancement after contrast injection. Time to maximum circumferential shortening varied more significantly over the left ventricle in patients than in volunteers (P<0.01). The proposed measurement scheme was well tolerated by patients and holds considerable potential to investigate cardiac mechanics in various diseases.

Conventional magnetic resonance imaging (MRI) is useful for assessing morphological changes but not for assessing deformations inside homogeneous structures (M. D. Abràmoff, A. P. Van Gils, G. H. Jansen, & M. P. Mourits, 2000). Since no intrinsic contrast can be imaged for distinguishing heterogeneous patterns of muscle contraction, morphological changes along the length of the extraocular muscles (EOMs) are not macroscopically detectable. However, an imaging method that is able to directly encode motion could give evidence about the dynamics of the inhomogeneous deformation of the EOMs. Thus, we developed a method for acquiring motion-encoded MRI images of the EOMs during eye movements. Seven healthy subjects gazed at a horizontal sinusoidally oscillating target. A small surface coil was placed in front of the right orbit. The contracting and relaxing horizontal rectus muscles and the noncontracting optic nerve were reliably tracked. The differential contractility of the EOMs could be distinguished from the third time frame on (=140 ms from the beginning of the right to left eye movement lasting 1 s). The muscle belly of the contracting medial rectus muscle could be distinguished from the posterior and the anterior segment from the sixth time frame on (=350 ms). In conclusion, motion-encoded MRI resolved the heterogeneous contraction of moving EOM segments in healthy subjects without using physical markers.

Progressive left ventricular hypertrophy is the hallmark of cardiac manifestations in patients with Fabry disease. Cardiovascular magnetic resonance with tissue tagging allows detailed assessment of the cardiac motion pattern. The aim was to test the hypothesis that not only Fabry patients with severe left ventricular hypertrophy exhibit changes in myocardial motion, but also Fabry patients with normal left ventricular mass. Magnetic resonance tagging using slice following complementary spatial modulation of magnetization (CSPAMM) combined with harmonic phase analysis (HARP) was applied to measure left ventricular shortening and contraction. Additionally, left ventricular rotation and global left ventricular torsion were examined. Twenty-nine Fabry patients grouped in patients with (n = 13) and without (n = 16) left ventricular hypertrophy were compared with 29 age and sex matched healthy volunteers. Long axis shortening and circumferential contraction showed reduced peak values with increasing left ventricular mass and were significantly reduced in Fabry patients with left ventricular hypertrophy (p < 0.001 and p < 0.05, respectively). Torsional deformation and apical rotation were increased both in Fabry patients with left ventricular hypertrophy as well as in patients with normal left ventricular mass (p < 0.001 for torsion) compared with controls. Applying the magnetic resonance tagging acquisition and analysis methods, myocardial motion abnormalities could not only be measured in Fabry patients with left ventricular hypertrophy but also in patients without macroscopic cardiac involvement.

Purpose: In ischemic myocardium systolic strain is reduced and followed by a deformation after systole, the so-called post-systolic shortening. The presence of post systolic shortening is therefore considered a marker of viability even though its mechanism remains unclear. The hypothesis was tested whether post-systolic shortening might be a passive recoil phenomenon and therefore not uniquely associated with viability., Methods: Five patients with a history of myocardial infarctions and fully transmural scars in late enhancement imaging and five age-matched healthy volunteers underwent a tagging study to analyze systolic and post-systolic deformation in transmurally infarcted and contra-lateral non-infarcted myocardium. From CSPAMM myocardial tagging data, mid-wall circumferential fiber shortening, radial displacement, and rotation parameters were semi-automatically extracted by harmonic phase (HARP)., Results: In transmurally infarcted myocardium, a post systolic shortening of 6.2 +/- 1.8% was present occurring in early diastole (time to maximum circumferential fiber shortening increased versus both, contralateral myocardium and corresponding sectors in healthy volunteers, p < 0.01). Maximum radial displacement was decreased in scar tissue (p < 0.001 versus contra-lateral), but time to maximum radial displacement did not differ. Rotation did not discriminate between infarcted and non-infarcted myocardium., Conclusions: The pure finding of post-systolic shortening is not sufficient for the diagnosis of residual myocardial viability. Post-systolic shortening may be explained in part by passive recoil, which releases energy stored in the scar tissue during systolic intra-ventricular unloading. Circumferential fiber shortening appears best suited for characterization of regional deformation, whereas radial displacement and rotation are more dependent on tethering effects, and thus, are more likely to reflect global chamber mechanics.

A TFEPI-CSPAMM sequence is introduced, which is optimized with respect to acquisition speed and image quality. The sequence is used in a stress study, where a short breath-hold duration is crucial, and tested for reproducibility of deformation parameters extracted by HARP for repeated measurements.