| 1. |
- Carlsson, Marcus, et al.
(författare)
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Coronary microembolization causes long-term detrimental effects on regional left ventricular function.
- 2011
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Ingår i: Scandinavian cardiovascular journal : SCJ. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 45, s. 205-214
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Objectives. To investigate whether coronary microemboli have long-term effects on left ventricular (LV) function in an experimental model. Furthermore, to determine if first-pass perfusion and late gadolinium enhancement (LGE) patterns differs between small- and large-sized microemboli. Design. Six pigs underwent left anterior descending (LAD)-coronary microembolization with small-sized (40-120 μm, n∼250 000) microemboli using a combined x-ray and MRI-system. MR-images before, one hour after and 7-8 weeks after microembolization were obtained. Results were compared to MRI obtained by large-sized (100-300 μm, n∼7200) microemboli. Results. Cine MRI showed an acute drop in ejection fraction (from 49.5 ± 2.6% to 32.5 ± 2.8) that substantially recovered at 7-8 weeks (47.5 ± 3.2%). Regional LV-function assessed as circumferential, longitudinal and radial strain declined in both microinfarcts and remote regions followed by partial recovery at 7-8 weeks. The decline in LV function and the severe perfusion deficit from the small microemboli was similar to the large microemboli at one hour. There was a significant recovery in perfusion at 7-8 weeks in the microinfarcts. LGE demonstrated the microinfarcts at 7-8 weeks but not at one hour and the microinfarcts were confirmed by histopathology. Conclusion. Microembolization causes long-term, regional LV dysfunction and this study confirmed the need of a comprehensive MRI-protocol for the detection of microinfarcts. These findings suggest that even small microemboli (40-120 μm in diameter), which may escape the distal protective devices influence cardiac function.
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| 2. |
- Carlsson, Marcus, et al.
(författare)
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Magnetic resonance imaging as a potential gold standard for infarct quantification.
- 2008
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 41, s. 614-620
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Tidskriftsartikel (refereegranskat)abstract
- Accurate diagnosis, characterization, and quantification of myocardial infarction (MI) is essential to assess the impact of therapy and to aid in predicting prognosis of patients with ischemic heart disease. Delayed contrast-enhanced magnetic resonance (DE-MR) imaging has the potential of being the gold standard for quantification of MI. It has also been useful in correlating electrocardiography abnormalities with the location and transmurality of infarction. The focus of this review is to address the strengths and limitations of DE-MR imaging in the detection and quantification of MI for clinicians and investigators in the field of electrocardiology. The biological rationale and technical background for detecting MI by DE-MR imaging were reviewed as well as the different approaches for quantification of the DE-MR images, exemplified by patient cases.
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| 3. |
- Dicks, Demetrius L., et al.
(författare)
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Persistent Decline in Longitudinal and Radial Strain After Coronary Microembolization Detected on Velocity Encoded Phase Contrast Magnetic Resonance Imaging
- 2009
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 30:1, s. 69-76
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Tidskriftsartikel (refereegranskat)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 = 6). The embolized area at risk was defined on perfusion MRI followed by administration of a 7500 count (size = 100-300 mu 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 -11.5 +/- 3.2% to 1.8 +/- 2.5% at 1 h (P < 0.05) and -3.9 +/- 1.1% at 1 week (P < 0.05). Similarly, regional radial strain progressively declined from 23.6 +/- 2.5% at baseline to 12.5 +/- 3.7% at 1 h (P < 0.05) and 4.8 +/- 5.0% at 1 week (P < 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.
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| 4. |
- Ordovas, Karen G., et al.
(författare)
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Impaired regional left ventricular strain after repair of tetralogy of fallot
- 2012
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 35:1, s. 79-85
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To test the potential of magnetic resonance imaging (MRI) in early detection of left ventricular (LV) dysfunction in patients with pulmonary regurgitation and normal LV ejection fraction after repair of tetralogy of Fallot. Materials and Methods: Patients (n = 18) with repaired tetralogy of Fallot and pulmonary regurgitation were prospectively recruited. Healthy volunteers (n = 10) were used as control. Tagging MR images were acquired at the base, mid, and apical LV levels for assessing segmental rotation and circumferential strain. Cine MR images and velocity- encoded MR images were also acquired for assessment of biventricular volumes and biventricular function and pulmonary regurgitant fraction, respectively. Mean values were compared between groups using unpaired Student's t- test. Results: Patients presented with preserved global LV function (LVEF of 59 +/- 5%). A significant decrease in LV peak circumferential strain was seen in patients compared with normal volunteers at the basilar (-15.6 +/- 4.5% vs. -17.6 +/- 4.4%; P < 0.01) and apical (-14.46 +/- 6.1% vs. -17.3 +/- 5.1%, P < 0.01) slices. LV peak rotation was also delayed in patients compared with volunteers at the basilar (6.1 +/- 2.6 degrees vs. 4.2 +/- 0.6 degrees; P < 0.01) and mid (8.0 +/- 1.7 degrees vs. 4.9 +/- 1.0 degrees; P < 0.01) slices. Conclusion: MRI can detect early regional LV dysfunction in patients with preserved LVEF after repair of tetralogy of Fallot. MR may be a useful technique for guiding clinical decisions in these patients in order to prevent future global LV deterioration.
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