Persistent decline in longitudinal and radial strain after coronary microembolization detected on velocity encoded phase contrast magnetic resonance imaging

Abstract

Purpose:To use velocity-encoded phase contrast (PC) MRI in assessing the effect of coronary microembolization on longitudinal and radial myocardial strain. Materials and Methods:A combined X-ray and MR system (XMR) was used for selective left anterior descending artery catheterization and microinfarct assessment in swine (n ϭ 6). The embolized area at risk was defined on perfusion MRI followed by administration of a 7500 count (size ϭ 100 -300 m) of the embolic agent. Quantification of strain and microinfarction was performed at 1 h and 1 week using PC-MRI and delayed enhancement (DE) MRI, respectively. At postmortem, sliced hearts were stained to define microinfarction.Results: Baseline longitudinal and radial strain did not differ between area-at-risk and remote myocardium. The embolized territory (area at risk) showed significant decline in longitudinal strain from Ϫ11.5 Ϯ 3.2% to 1.8 Ϯ 2.5% at 1 h (P Ͻ 0.05) and Ϫ3.9 Ϯ 1.1% at 1 week (P Ͻ 0.05). Similarly, regional radial strain progressively declined from 23.6 Ϯ 2.5% at baseline to 12.5 Ϯ 3.7% at 1 h (P Ͻ 0.05) and 4.8 Ϯ 5.0% at 1 week (P Ͻ 0.01). The size of microinfarction was not significantly different between DE-MRI and histochemical staining. Conclusion:PC-MRI is sensitive in assessing changes in regional longitudinal and radial strain after coronary embolization. Longitudinal and radial strain of the hyperenhanced patchy microinfarction demonstrates persistent decline over the course of 1 week.

Validation of Longitudinal Peak Systolic Strain by Speckle Tracking Echocardiography With Visual Assessment and Myocardial Perfusion SPECT in Patients With Regional Asynergy

“…SPECT analysis has high objectivity, reproducibility and automatically scores WT, so we used this method for gold standard. Although WT measured by SPECT is a parameter of radial thickening and LS by AFI is a measurement of longitudinal strain, radial thickening and longitudinal shortening are thought to be strongly linked 28 and there were good correlations between those parameters in our study. However, in segments with a variable extent of transmural necrosis, the longitudinal (subendocardium) and radial (mid layers) functions may differ.…”

Cardiovascular magnetic resonance imaging in delivering and evaluating the efficacy of hepatocyte growth factor gene in chronic infarct scar

“…Segment software was used by investigators blinded to treatment to determine LV volumes, ejection fraction, mass, perfusion, infarct size and transmurality and for measuring, longitudinal and systolic wall thickening (radial strain) 5, 17, 19 . Regional wall thickness at end systole and end diastole of infarct scar (the target) and remote segments (LV free wall) were obtained, using DE-MR imaging as guidance.…”

“…A total of 576 segments was measured for segmental systolic wall thickening covering 5 weeks after infarction and 5 weeks after delivery of genes time points using Segment software, while HARP software was used blinded to treatment for measurement of peak systolic circumferential strain 20 . For image registration of the circumferential strain the LV and the anterio-septal groove were used as the anatomic landmark 5, 19, 21 . The radial, circumferential and longitudinal strain were assessed in the same apical slices containing the infarct, shown on DE-MR images.…”

MR fluoroscopy in vascular and cardiac interventions (review)

“…In pre and post-intervention the following MR sequences were used: (a) balanced fast field echo CINE images for measuring LV volumes, ejection fraction, cardiac output, stroke volume, LV mass, wall thickness and radial strain [90, 112–114], (b) tagged gradient echo planar imaging for measuring circumferential strain and LV rotation [115, 116], (c) phase-contrast velocity-encoded gradient echo planar imaging for measuring longitudinal strain [117], (d) T 2 -weighted turbo spin echo sequence for measuring interstitial edema after ablation, (e) T 2 * multi-echo gradient echo sequence for measuring vascular and myocardial hemorrhage after intervention [118], (f) T 1 -weighted gradient echo (radiofrequency spoiled) perfusion imaging sequence for measuring myocardial perfusion changes after delivery of therapy, and (g) delayed contrast enhanced 3D T 1 -weighted gradient echo sequence for assessing tissue viability.…”