C Schönfeld

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).

Quantification of Pulmonary Inflammation after Segmental Allergen Challenge Using Turbo-Inversion Recovery-Magnitude Magnetic Resonance Imaging

RATIONALE There is a need to develop novel noninvasive imaging biomarkers that help to evaluate antiinflammatory asthma treatments. OBJECTIVES To investigate whether the extent of the segmental lung edema measured noninvasively using turbo-inversion recovery-magnitude magnetic resonance imaging (TIRM MRI) corresponds to the severity of the regional allergic reaction determined by the percentage of eosinophils in bronchoalveolar lavage fluid (BAL) 24 hours after segmental allergen challenge in patients with asthma compared with normal control subjects. METHODS Eleven volunteers with allergic asthma and five healthy volunteers underwent segmental challenges with different allergen doses by two bronchoscopies 24 hours apart. They had lung MRI at baseline and 6 and 24 hours after segmental challenge. MRI TIRM scores were correlated with the eosinophilic response at 24 hours. MEASUREMENTS AND MAIN RESULTS In patients with asthma, there were significant differences of eosinophil percentages in BAL at 24 hours from segments given standard-dose, low-dose, or no allergen (saline) (P < 0.001). Correspondingly significant differences between the TIRM score in allergen standard-dose, low-dose, and saline-treated segments were observed at 24 hours post-challenge (P < 0.001). With increasing TIRM score at 24 hours the percent eosinophils per segment 24 hours post-challenge also increased accordingly (P < 0.001). There was interobserver agreement for TIRM score grading (kappa = 0.72 for 24-h time point). CONCLUSIONS The MRI-based noninvasive TIRM score is a promising biomarker for the noninvasive detection of the inflammatory response after segmental allergen challenge in patients with asthma and may serve to monitor the therapeutic effectiveness of novel antiinflammatory drugs in future human trials.

Chronic Lung Allograft Dysfunction: Oxygen-enhanced T1-Mapping MR Imaging of the Lung

PURPOSE To evaluate oxygen-enhanced T1-mapping magnetic resonance (MR) imaging of the lungs for detection of chronic lung allograft dysfunction (CLAD) in patients who have undergone double lung transplantation. MATERIALS AND METHODS The local ethics committee approved this study. Seventy-six recipients of double lung allografts who underwent MR imaging of the lungs during an outpatient visit between 2011 and 2013 were included in this study after they provided written informed consent. Patients were classified as having CLAD on the basis of spirometric results and were divided into three groups: no CLAD (bronchiolitis obliterans syndrome level 0 [BOS 0]), early CLAD (BOS 0p), and late-stage CLAD (BOS 1-3). Coronal T1 maps of the lungs were acquired with the patient breathing room air and 100% oxygen by using an inversion-recovery snapshot fast low-angle shot sequence at 1.5 T. The median and interquartile range of T1 values at room air and at 100% oxygen and the oxygen transfer function were calculated. Statistical analysis was performed with analysis of variance and the Tukey honestly significant difference test or the Kruskal-Wallis test and the Mann-Whitney U test (α = 0.05). Bonferroni correction was applied for multiple comparisons. RESULTS The oxygen transfer function was significantly lower in patients in the BOS 0p (P = .025) and BOS 1-3 groups (P = .003) than it was in the patients with BOS 0. Absolute T1 values (room air, P = .66; 100% oxygen, P = .67) did not differ significantly among the groups. The heterogeneity of T1 values, measured by using the interquartile range, showed a strong trend toward higher values in patients with BOS (room air, P = .06; 100% oxygen, P = .08). CONCLUSION Oxygen transfer function may serve as an early marker for detection of CLAD.

Noninvasive Quantification of Airway Inflammation Following Segmental Allergen Challenge with Functional MR Imaging: A Proof of Concept Study

PURPOSE To evaluate oxygen-enhanced T1-mapping magnetic resonance (MR) imaging as a noninvasive method for visualization and quantification of regional inflammation after segmental allergen challenge in asthmatic patients compared with control subjects. MATERIALS AND METHODS After institutional review board approval, nine asthmatic and four healthy individuals gave written informed consent. MR imaging (1.5 T) was performed by using an inversion-recovery snapshot fast low-angle shot sequence before (0 hours) and 6 hours and 24 hours after segmental allergen challenge by using either normal- or low-dose allergen or saline. The volume of lung tissue with increased relaxation times was determined by using a threshold-based method. As a biomarker for oxygen transfer from the lungs into the blood, the oxygen transfer function ( OTF oxygen transfer function ) was calculated. After the third MR imaging examination, eosinophils in bronchoalveolar lavage fluid were counted. Differences between times and segments were analyzed with nonparametric Wilcoxon matched-pairs test and Spearman correlation. RESULTS In lung segments treated with the standard dose of allergen, the OTF oxygen transfer function was decreased at 6 hours in asthmatic patients, compared with saline-treated segments (P = .0078). In asthmatic patients at 24 hours, the volume over threshold was significantly increased in normal allergen dose-treated segments compared with saline-treated segments (P = .004). In corresponding lung segments, the volume over threshold at 24 hours in the asthmatic group showed a positive correlation (r = 0.65, P = .0001) and the OTF oxygen transfer function at 6 hours showed an inverse correlation (r = -0.67, P = .0001) with the percentage of eosinophils in the bronchoalveolar lavage fluid. CONCLUSION OTF oxygen transfer function and volume over threshold are noninvasive MR imaging-derived parameters to visualize and quantify the regional allergic reaction after segmental endobronchial allergen challenge.

Clinical use of oxygen-enhanced T1 mapping MRI of the lung: Reproducibility and impact of closed versus loose fit oxygen delivery system

To evaluate the reproducibility of oxygen‐enhanced magnetic resonance imaging (MRI), and the influence of different gas delivery methods, in a clinical environment.

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.

Quantifizierung pulmonaler Inflammation nach endobronchialer Allergenprovokation mittels Turbo-Inversion Recovery-Magnitude (TIRM) MRT

Material: Dreizehn Patienten mit CTEPH wurden mittels MRT (1,5 T) und mittels Tc-99m-HSA-Mikrosphären SPECT untersucht, acht Patienten erhielten zusätzlich eine Rechtsherzkatheteruntersuchung (RHK). Phasenkontrast-MRT Messungen wurden in der Aorta (AO) im Truncus pulmonalis (TP), in der rechten und linken Arteria pulmonalis (rPA / lPA) mit einer zeitlichen Auflösung von 10-20 ms durchgeführt. Die Verhältnisse zwischen den Flussraten der rechten Lunge zur gesamten Lunge, sowie die mittlere Flussgeschwindigkeit und Distensibilität im TP, wurden berechnet. Die Zählereignisse beider Lungen und der Quotient zwischen rechter Lunge und den Gesamtzählereignissen wurden bestimmt. Im RHK wurde der mPAP bestimmt. Es wurde eine Regressionsanalyse und Bland-Altman-Analyse durchgeführt. Der RHK wurde mittels Spearmans-Rho Test mit den MRT-Flussdaten korreliert.

Vergleich der SPECT mit der dynamischen, kontrastmittelverstärkten Perfusions-MRT und der MR-Fourier-Dekomposition zur Diagnose der chronischen thromboembolischen pulmonalen Hypertonie (CTEPH)

Material: Dreizehn Patienten mit CTEPH wurden mittels MRT (1,5 T) und mittels Tc-99m-HSA-Mikrosphären SPECT untersucht, acht Patienten erhielten zusätzlich eine Rechtsherzkatheteruntersuchung (RHK). Phasenkontrast-MRT Messungen wurden in der Aorta (AO) im Truncus pulmonalis (TP), in der rechten und linken Arteria pulmonalis (rPA / lPA) mit einer zeitlichen Auflösung von 10-20 ms durchgeführt. Die Verhältnisse zwischen den Flussraten der rechten Lunge zur gesamten Lunge, sowie die mittlere Flussgeschwindigkeit und Distensibilität im TP, wurden berechnet. Die Zählereignisse beider Lungen und der Quotient zwischen rechter Lunge und den Gesamtzählereignissen wurden bestimmt. Im RHK wurde der mPAP bestimmt. Es wurde eine Regressionsanalyse und Bland-Altman-Analyse durchgeführt. Der RHK wurde mittels Spearmans-Rho Test mit den MRT-Flussdaten korreliert.