Acute COPD exacerbation: 3 T MRI evaluation of pulmonary regional perfusion--preliminary experience.

OBJECTIVES: To compare pulmonary perfusion parameters by means of dynamic perfusion magnetic resonance in patients affected by chronic obstructive pulmonary disease (COPD), during and after acute exacerbation. METHODS: Fifteen patients were successfully evaluated with perfusional MRI during an acute exacerbation of COPD and upon clinical stabilization. Inclusion criteria were a PaCO2 > 45 mmHg and respiratory acidosis (arterial blood pH < 7.35) at admittance. RESULTS: In the acute phase a reduction of pulmonary blood flow (PBF) and pulmonary blood volume (PBV), and a significant prolonging of the mean transit time (MTT) and time to peak (TTP) were observed in all patients. In the stabilization phase a significant increase of PBF and PBV and a significant reduction of MTT and TTP were observed in 6 patients; no significant variations were observed in the other 9 patients. CONCLUSION: 3D time-resolved contrast-enhanced MRI allows quantitative evaluation of pulmonary regional perfusion in patients affected by COPD, identifying patients in which perfusion defects are resolved in the clinical-stabilization phase. This technique might allow the identification of patients in whom vasospasm may be the main responsible of pulmonary hypoperfusion during acute COPD exacerbation, with potential advantages on the clinical management of these patients.