Jennia N. Rajaei

All Publications

• Hyperpolarized Gas Diffusion MRI of Biphasic Lung Inflation in Short and Long Term Emphysema Models. American journal of physiology. Lung cellular and molecular physiology Xin, Y., Cereda, M., Kadlecek, S., Emami, K., Hamedani, H., Duncan, I., Rajaei, J., Hughes, L., Meeder, N., Naji, J., Profka, H., Bolognese, B. J., Foley, J. P., Podolin, P. L., Rizi, R. R. 2017: ajplung 00048 2017-?

  Abstract

  During lung-inflation, airspace dimensions are affected non-linearly by both alveolar expansion and recruitment, potentially confounding the identification of emphysematous lung by hyperpolarized helium-3 diffusion magnetic resonance imaging (HP MRI). This study aimed to characterize lung inflation over a broad range of inflation volume and pressure values in two different models of emphysema, as well as in normal lungs. Elastase-treated rats (n=7) and healthy controls (n=7) were imaged with HP MRI. Gradual inflation was achieved by incremental changes to both inflation volume and airway pressure. The apparent diffusion coefficient (ADC) was measured at each level of inflation and fitted to the corresponding airway pressures as the second order response equation, with minimizing residue (2<0.001). A biphasic ADC response was detected, with an initial ADC increase followed by a decrease at airway pressures >18 cmH2O. Discrimination between treated and control rats was optimal when airway pressure was intermediate (between 10-11 cmH2O). Similar findings were confirmed in mice following long-term exposure to cigarette smoke, where optimal discrimination between treated and healthy mice occurred at a similar airway pressure as in the rats. We subsequently explored the evolution of ADC measured at the intermediate inflation level in mice after prolonged smoke exposure, and found a significant increase (P<0.01) in ADC over time. Our results demonstrate that measuring ADC at intermediate inflation enhances the distinction between healthy and diseased lungs, thereby establishing a model that may improve the diagnostic accuracy of future HP gas diffusion studies.

  View details for DOI 10.1152/ajplung.00048.2017

  View details for PubMedID 28473321

• C] pyruvate. Magnetic resonance in medicine Pourfathi, M., Xin, Y., Kadlecek, S. J., Cereda, M. F., Profka, H., Hamedani, H., Siddiqui, S. M., Ruppert, K., Drachman, N. A., Rajaei, J. N., Rizi, R. R. 2017

  Abstract

  To investigate pulmonary metabolic alterations during progression of acute lung injury.Using hyperpolarized [1-(13) C] pyruvate imaging, we measured pulmonary lactate and pyruvate in 15 ventilated rats 1, 2, and 4 h after initiation of mechanical ventilation. Lung compliance was used as a marker for injury progression. 5 untreated rats were used as controls; 5 rats (injured-1) received 1 ml/kg and another 5 rats (injured-2) received 2 ml/kg hydrochloric acid (pH 1.25) in the trachea at 70 min.The mean lactate-to-pyruvate ratio of the injured-1 cohort was 0.15 ± 0.02 and 0.15 ± 0.03 at baseline and 1 h after the injury, and significantly increased from the baseline value 3 h after the injury to 0.23 ± 0.02 (P = 0.002). The mean lactate-to-pyruvate ratio of the injured-2 cohort decreased from 0.14 ± 0.03 at baseline to 0.08 ± 0.02 1 h after the injury and further decreased to 0.07 ± 0.02 (P = 0.08) 3 h after injury. No significant change was observed in the control group. Compliance in both injured groups decreased significantly after the injury (P < 0.01).Our findings suggest that in severe cases of lung injury, edema and hyperperfusion in the injured lung tissue may complicate interpretation of the pulmonary lactate-to-pyruvate ratio as a marker of inflammation. However, combining the lactate-to-pyruvate ratio with pulmonary compliance provides more insight into the progression of the injury and its severity. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  View details for DOI 10.1002/mrm.26604

  View details for PubMedID 28074497