Search

Background: 19F MRI of inhaled gas tracers has developed into a promising tool for pulmonary diagnostics. Prior to clinical use, the intersession repeatability of acquired ventilation parameters must be quantified and maximized. Purpose: To evaluate repeatability of static and dynamic 19F ventilation parameters and correlation with predicted forced expiratory volume in 1 second (FEV1%pred) with and without inspiratory volume control. Study Type: Prospective. Population: A total of 30 healthy subjects and 26 patients with chronic obstructive pulmonary disease (COPD). Field Strength/Sequence: Three‐dimensional (3D) gradient echo pulse sequence with golden‐angle stack‐of‐stars k‐space encoding at 1.5 T. Assessment: All study participants underwent 19F ventilation MRI over eight breaths with inspiratory volume control (w VC) and without inspiratory volume control (w/o VC), which was repeated within 1 week. Ventilated volume percentage (VVP), fractional ventilation (FV), and wash‐in time (WI) were computed. Lung function testing was conducted on the first visit. Statistical Tests: Correlation between imaging and FEV1%pred was measured using Pearson correlation coefficient (r). Differences in imaging parameters between first and second visit were analyzed using paired t‐test. Repeatability was quantified using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Minimum detectable effect size (MDES) was calculated with a power analysis for study size n = 30 and a power of 0.8. All hypotheses were tested with a significance level of 5% two sided. Results: Strong and moderate linear correlations with FEV1%pred for COPD patients were found in almost all imaging parameters. The ICC w VC exceeds the ICC w/o VC for all imaging parameters. CoV was significantly lower w VC for initial VVP in COPD patients, FV, CoV FV, WI and standard deviation (SD) of WI. MDES of all imaging parameters were smaller w VC. Data Conclusion: 19F gas wash‐in MRI with inspiratory volume control increases the correlation and repeatability of imaging parameters with lung function testing. Evidence Level: 2 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Purpose: To test the feasibility of 3D phase‐resolved functional lung (PREFUL) MRI in healthy volunteers and patients with chronic pulmonary disease, to compare 3D to 2D PREFUL, and to investigate the required temporal resolution to obtain stable 3D PREFUL measurement. Methods: Sixteen participants underwent MRI using 2D and 3D PREFUL. Retrospectively, the spatial resolution of 3D PREFUL (4 × 4 × 4 mm3) was decreased to match the spatial resolution of 2D PREFUL (4 × 4 × 15 mm3), abbreviated as 3Dlowres. In addition to regional ventilation (RVent), flow‐volume loops were computed and rated by a cross‐correlation (CC). Ventilation defect percentage (VDP) maps were obtained. RVent, CC, VDPRVent, and VDPCC were compared for systematic differences between 2D, 3Dlowres, and 3D PREFUL. Dividing the 3D PREFUL data into 4‐ (≈ 20 phases), 8‐ (≈ 40 phases), and 12‐min (≈ 60 phases) acquisition pieces, the ventilation parameter maps, including the heterogeneity of ventilation time to peak, were tested regarding the required temporal resolution. Results: RVent, CC, VDPRVent, and VDPCC presented significant correlations between 2D and 3D PREFUL (r = 0.64‐0.94). CC and VDPCC of 2D and 3Dlowres PREFUL were significantly different (P <.0113). Comparing 3Dlowres and 3D PREFUL, all parameters were found to be statistically different (P <.0045). Conclusion: 3D PREFUL MRI depicts the whole lung volume and breathing cycle with superior image resolution and with likely more precision compared to 2D PREFUL. Furthermore, 3D PREFUL is more sensitive to detect regions of hypoventilation and ventilation heterogeneity compared to 3Dlowres PREFUL, which is important for early detection and improved monitoring of patients with chronic lung disease. [ABSTRACT FROM AUTHOR]

Background: 19 F MRI of inhaled gas tracers has developed into a promising tool for pulmonary diagnostics. Prior to clinical use, the intersession repeatability of acquired ventilation parameters must be quantified and maximized., Purpose: To evaluate repeatability of static and dynamic 19 F ventilation parameters and correlation with predicted forced expiratory volume in 1 second (FEV 1 %pred) with and without inspiratory volume control., Study Type: Prospective., Population: A total of 30 healthy subjects and 26 patients with chronic obstructive pulmonary disease (COPD)., Field Strength/sequence: Three-dimensional (3D) gradient echo pulse sequence with golden-angle stack-of-stars k-space encoding at 1.5 T., Assessment: All study participants underwent 19 F ventilation MRI over eight breaths with inspiratory volume control (w VC) and without inspiratory volume control (w/o VC), which was repeated within 1 week. Ventilated volume percentage (VVP), fractional ventilation (FV), and wash-in time (WI) were computed. Lung function testing was conducted on the first visit., Statistical Tests: Correlation between imaging and FEV 1 %pred was measured using Pearson correlation coefficient (r). Differences in imaging parameters between first and second visit were analyzed using paired t-test. Repeatability was quantified using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Minimum detectable effect size (MDES) was calculated with a power analysis for study size n = 30 and a power of 0.8. All hypotheses were tested with a significance level of 5% two sided., Results: Strong and moderate linear correlations with FEV 1 %pred for COPD patients were found in almost all imaging parameters. The ICC w VC exceeds the ICC w/o VC for all imaging parameters. CoV was significantly lower w VC for initial VVP in COPD patients, FV, CoV FV, WI and standard deviation (SD) of WI. MDES of all imaging parameters were smaller w VC., Data Conclusion: 19 F gas wash-in MRI with inspiratory volume control increases the correlation and repeatability of imaging parameters with lung function testing., Evidence Level: 2 TECHNICAL EFFICACY: Stage 2., (© 2022 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)