Phase-contrast MRI for detection of mild systemic hemodynamic response after segmental allergen challenge in asthmatic patients

Acad Radiol. 2014 Aug;21(8):994-1001. doi: 10.1016/j.acra.2014.03.003.

Abstract

Rationale and objectives: Detection of a systemic hemodynamic response in patients suffering from allergic asthma after segmental endobronchial allergen challenge using phase-contrast magnetic resonance imaging (MRI).

Materials and methods: Nine asthma patients and four healthy volunteers were examined using MRI (1.5T) before (0 hour), 6 hours, and 24 hours after segmental allergen challenge. Two-dimensional phase-contrast MRI measurements were performed in the aorta (AO) and in the pulmonary artery (PA). In addition, short-axis balanced steady state free precession cardiac cine MRI was performed. Maximum systolic flow, maximum flow acceleration, acceleration volume, acceleration time, distensibility, ejection fraction, stroke volume, end-systolic/diastolic volume, cardiac mass, heart rate (HR), and cardiac output (CO) were determined. Spirometry and bronchoalveolar lavage were also performed.

Results: In patients with asthma, maximal systolic flow and maximal flow acceleration increased 6 hours after provocation in the AO (112.3% and 118.9%, respectively) and PA (113.9% and 116.0%, respectively) compared to baseline (100%, P < .05). HR and CO increased significantly at 6 hours (115% and 118%, respectively) compared to baseline (100%, P = .003). In healthy subjects, almost all MRI-derived hemodynamic parameters did not significantly change at 6 hours and were significantly lower than baseline values at 24 hours (P < .02). Twenty-four hours after allergen challenge, all MRI-derived flow parameters were significantly lower in the control group compared to the asthma group (P < .05). HR, CO, and cardiac function parameters measured at 24 hours showed no significant difference comparing the two groups (P > .05).

Conclusions: In asthmatic patients, MRI-derived hemodynamic parameters using phase-contrast MRI are slightly altered after segmental allergen provocation compared to normal controls indicating a mild systemic reaction to local allergen challenge.

Keywords: Phase-contrast MRI; asthma bronchiale; endobronchial allergen challenge.

MeSH terms

  • Adult
  • Algorithms
  • Allergens
  • Asthma / diagnosis*
  • Asthma / physiopathology*
  • Blood Flow Velocity
  • Bronchial Provocation Tests / methods*
  • Female
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods*
  • Magnetic Resonance Angiography / methods*
  • Magnetic Resonance Imaging, Cine / methods*
  • Male
  • Middle Aged
  • Pulmonary Circulation*
  • Reproducibility of Results
  • Sensitivity and Specificity

Substances

  • Allergens