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[MRI first-pass myocardial perfusion in patients undergoing percutaneous myocardial laser revascularization]
1Radiologische Klinik und Poliklinik, Abteilung für Röntgendiagnostik, Universitätsklinikum Hamburg Eppendorf. C.Weber@uke.uni-hamburg.de
Purpose:
Evaluation of MRI first-pass myocardial perfusion pre- and post-percutaneous myocardial laser revascularisation (PMR).
Patients And Methods:
MRI was performed in 10 patients with coronary heart disease grade III-IV, 1-4 days prior to PMR, as well as 1-5 days and 6 months after PMR. Contrast enhanced (0.1 ml/kgBw; 4 ml/s) "first-pass" MRI imaging was obtained by breath-hold, ECG-triggered, multislice Turbo-FLASH GRE. For quantitative analysis the absolute and percentual signal-to-noise (S/N)-measurements were calculated. Positron emission tomography (PET) was regarded as the gold standard for myocardial perfusion.
Results:
The mean values of absolute and % S/N increase revealed no statistical difference between pre- and immediately post-PMR imaging. 6 months following PMR both values were significantly elevated (14.1 vs. 24.4 and 127 vs. 176; p = 0.03 and p = 0.01). However, the non-treated myocardial segments revealed a similar S/N pattern. Intraindividual analysis showed a significant S/N increase post PMR in one patient, and in additional 4 patients 6 months later. PET revealed increased myocardial perfusion in only two patients. Following PMR 5/10 patients experienced a significant reduction of chest pain equivalent to two CCS grades. Two of these had significant S/N elevations but no evidence of increased perfusion by PET.
Conclusion:
S/N first-pass calculations following PMR do not correlate well with the true situation of myocardial perfusion. They seem to be more closely associated with other histological phenomena and possible explanations for the improved clinical symptomatology.
Insights
MRI first-pass signal-to-noise (S/N) measurements after percutaneous myocardial laser revascularisation (PMR) did not reflect true myocardial perfusion. S/N changes may indicate other histological effects contributing to symptom improvement in coronary heart disease patients.
Area of Science:
- Cardiovascular Imaging
- Interventional Cardiology
- Medical Technology
Background:
- Coronary heart disease (CHD) management often involves revascularisation procedures.
- Assessing the efficacy of interventions like percutaneous myocardial laser revascularisation (PMR) is crucial.
- Magnetic Resonance Imaging (MRI) offers non-invasive methods for evaluating myocardial perfusion.
Purpose of the Study:
- To evaluate MRI first-pass myocardial perfusion imaging before and after PMR.
- To assess the correlation between MRI signal-to-noise (S/N) changes and actual myocardial perfusion.
- To explore potential explanations for clinical improvements post-PMR.
Main Methods:
- 10 patients with severe CHD underwent MRI first-pass perfusion scans pre-PMR and at 1-5 days and 6 months post-PMR.
- Contrast-enhanced, ECG-triggered Turbo-FLASH GRE sequences were used for imaging.
- Quantitative analysis involved absolute and percentual S/N measurements; Positron Emission Tomography (PET) served as the gold standard.
Main Results:
- No significant difference in S/N increase was observed immediately after PMR compared to pre-PMR.
- A significant elevation in S/N values was noted 6 months post-PMR (p=0.03 and p=0.01).
- PET showed increased perfusion in only two patients, and S/N changes did not consistently correlate with PET findings or improved chest pain in some patients.
Conclusions:
- MRI first-pass S/N calculations post-PMR do not accurately reflect changes in myocardial perfusion.
- S/N measurements may be influenced by histological changes rather than direct perfusion improvements.
- The study suggests that improved clinical symptoms post-PMR might be linked to factors beyond enhanced myocardial perfusion detectable by this MRI technique.