Andreas Voskrebenzev

Performance of perfusion-weighted Fourier decomposition MRI for detection of chronic pulmonary emboli

To evaluate the test performance of perfusion‐weighted Fourier‐decomposition (pw‐FD) magnetic resonance imaging (MRI) in comparison to dynamic contrast‐enhanced (DCE)‐MRI as a reference standard in patients with known or suspected chronic pulmonary embolism (PE).

MR Imaging–derived Regional Pulmonary Parenchymal Perfusion and Cardiac Function for Monitoring Patients with Chronic Thromboembolic Pulmonary Hypertension before and after Pulmonary Endarterectomy

Purpose To evaluate surgical success after pulmonary endarterectomy (PEA) by means of cardiopulmonary magnetic resonance (MR) imaging. Materials and Methods In this institutional review board-approved study, 20 patients with chronic thromboembolic pulmonary hypertension were examined at 1.5 T with a dynamic contrast material-enhanced three-dimensional fast low-angle shot sequence before and 12 days after PEA (25th-75th percentile range, 11-16 days). Lung segments were evaluated visually before PEA for parenchymal hypoperfused segments. Pulmonary blood flow (PBF), first-pass bolus kinetic parameters, and biventricular mass and function were determined. Mean pulmonary artery pressure (mPAP) and 6-minute walking distance were measured before and after PEA. The Shapiro-Wilk test, paired two-sided Wilcoxon rank sum test, Spearman ρ correlation, and multiple linear regression analysis were performed. Results Two weeks after PEA, regional PBF increased 66% in the total lung from 32.7 to 54.2 mL/min/100 mL (P = .0002). However, after adjustment for cardiac output, this change was not evident anymore (increase of 7% from 7.03 to 7.54 mL/min/100 mL/L/min, P = .1). Only in the lower lobes, a significant increase in PBF after cardiac output adjustment remained: a 16% increase in the right lower lobe from 7.53 to 8.71 mL/min/100 mL (P = .01) and a 14% increase in the left lower lobe from 7.42 to 8.47 mL/min/100 mL/L/min (P < .05). Right ventricular mass and function also improved. mPAP decreased from 46 to 24 mm Hg (P < .0001). Six-minute walking distance increased from 390 to 467 m (P = .02) 5 months after PEA. Percentage change of mPAP and PBF in the lower lobe tended to be significant predictors of percentage change in 6-minute walking distance (β = -1.79 [P = .054] and β = 0.45 [P = .076], respectively) in multiple linear regression analysis. Conclusion Improvement of PBF after PEA was observed predominantly in the lower lungs, and the magnitude of improvement of PBF in the lower lobes correlated with the improvement in exercise capacity, reflecting surgical success. (©) RSNA, 2016.

Reproducibility of fractional ventilation derived by Fourier decomposition after adjusting for tidal volume with and without an MRI compatible spirometer

To reduce the influence of tidal volume on fractional ventilation (FV) derived by Fourier decomposition (FD).

Low-pass imaging of dynamic acquisitions (LIDA) with a group-oriented registration (GOREG) for proton MR imaging of lung ventilation

To compare low‐pass imaging dynamic acquisitions (LIDA) approach in combination with a group‐oriented registration (GOREG) scheme with conventional Fourier decomposition (FD).

Feasibility of quantitative regional ventilation and perfusion mapping with phase-resolved functional lung (PREFUL) MRI in healthy volunteers and COPD, CTEPH, and CF patients: Phase-Resolved Functional Lung MRI

In this feasibility study, a phase‐resolved functional lung imaging postprocessing method for extraction of dynamic perfusion (Q) and ventilation (V) parameters using a conventional 1H lung MRI Fourier decomposition acquisition is introduced.

Comparison of quantitative regional ventilation-weighted fourier decomposition MRI with dynamic fluorinated gas washout MRI and lung function testing in COPD patients: Comparison of FD-MRI With 19F-MRI

Ventilation‐weighted Fourier decomposition‐MRI (FD‐MRI) has matured as a reliable technique for quantitative measures of regional lung ventilation in recent years, but has yet not been validated in COPD patients.

Free-breathing Dynamic 19F Gas MR Imaging for Mapping of Regional Lung Ventilation in Patients with COPD

Purpose To quantify regional lung ventilation in patients with chronic obstructive pulmonary disease (COPD) by using free-breathing dynamic fluorinated (fluorine 19 [19F]) gas magnetic resonance (MR) imaging. Materials and Methods In this institutional review board-approved prospective study, 27 patients with COPD were examined by using breath-hold 19F gas wash-in MR imaging during inhalation of a normoxic fluorinated gas mixture (perfluoropropane) and by using free-breathing dynamic 19F gas washout MR imaging after inhalation of the gas mixture was finished for a total of 25-30 L. Regional lung ventilation was quantified by using volume defect percentage (VDP), washout time, number of breaths, and fractional ventilation (FV). To compare different lung function parameters, Pearson correlation coefficient and Fisher z transformation were used, which were corrected for multiple comparisons with the Bonferroni method. Results Statistically significant correlations were observed for all evaluated lung function test parameters compared with median and interquartile range of 19F washout parameters. An inverse linear correlation of median number of breaths (r = -0.82; P < .0001) and median washout times (r = -0.77; P < .0001) with percentage predicted of forced expiratory volume in 1 second (FEV1) was observed; correspondingly median FV (r = 0.86; P < .0001) correlated positively with percentage predicted FEV1. Comparing initial with late phase, median VDP of all subjects decreased from 49% (25th-75th percentile, 35%-62%) to 6% (25th-75th percentile, 2%-10%; P < .0001). VDP at the beginning of the gas wash-in phase (VDPinitial) significantly correlated with percentage predicted FEV1 (r = -0.74; P = .0028) and FV (r = 0.74; P = .0002). Median FV was significantly increased in ventilated regions (11.1% [25th-75th percentile, 6.8%-14.5%]) compared with the defect regions identified by VDPinitial (5.8% [25th-75th percentile, 4.0%-7.4%]; P < .0001). Conclusion Quantification of regional lung ventilation by using dynamic 19F gas washout MR imaging in free breathing is feasible at 1.5 T even in obstructed lung segments.

Regional investigation of lung function and microstructure parameters by localized 129Xe chemical shift saturation recovery and dissolved-phase imaging: A reproducibility study

To evaluate the reproducibility and regional variation of parameters obtained from localized 129Xe chemical shift saturation recovery (CSSR) MR spectroscopy in healthy volunteers and patients with chronic obstructive pulmonary disease (COPD) and to compare the results to 129Xe dissolved‐phase MR imaging.

Mapping of regional lung microstructural parameters using hyperpolarized 129Xe dissolved-phase MRI in healthy volunteers and patients with chronic obstructive pulmonary disease

To develop a novel technique for voxel‐based mapping of lung microstructural parameters using hyperpolarized 129Xe dissolved‐phase MR imaging during saturation recovery.

Comparison of quantitative regional perfusion-weighted phase resolved functional lung (PREFUL) MRI with dynamic gadolinium-enhanced regional pulmonary perfusion MRI in COPD patients: Comparison of PREFUL-MRI With DCE-MRI

Perfusion‐weighted noncontrast‐enhanced proton lung MRI during free breathing is maturing as a novel technique for assessment of regional lung perfusion, but has not yet been validated in chronic obstructive pulmonary disease (COPD) patients.