TRADITIONAL POSTER - ismrm

Poster Sessions
2534. Detection and Characterization of Physiologic Lung Changes After Placement of Bronchial Valves: A
Case Study.
Jaime Mata 1 , Talissa Altes 1 , Steve Springmeyer 2 , Jonathon Truwit 1 , Eduard de Lange 1 , Peter Sylvester 1 ,
John Mugler III 1
1 University of Virginia, Charlottesville, VA, United States; 2 Spiration Inc, Redmond, WA, United States
The purpose was to determine whether hyperpolarized helium-3 (HHe) ventilation and diffusion MR imaging can detect changes in lung function and
microstructure resulting from bronchial valve placement.
One subject was imaged with HHe, pre and 6-month post IBV placement. Physiological changes of the lung were observed and quantified.
In conclusion, HHe MR imaging appears to provide a safe, non-invasive method for measuring functional and structural changes in the lungs after IBV
placement.
2535. Acinar Structural Changes in Mild COPD Detected by in Vivo Lung Morphometry with
Hyperpolarized Helium-3 MRI
James D. Quirk 1 , Barbara A. Lutey 2 , Jason C. Woods 1,3 , Alexander L. Sukstanskii 1 , Mark S. Conradi, 1,3 ,
Mario Castro 2 , David S. Gierada 1 , Dmitriy A. Yablonskiy 1,3
1 Radiology, Washington University School of Medicine, St. Louis, MO, United States; 2 Internal Medicine, Washington University
School of Medicine, St. Louis, MO, United States; 3 Physics, Washington University, St. Louis, MO, United States
In vivo lung morphometry with hyperpolarized helium-3 MRI is a sensitive method for detecting early emphysema and provides a unique insight into
changes in the acinar microstructure. We utilized this technique to measure acinar geometrical parameters in 30 smokers and 5 healthy volunteers. Our
results support the view that early emphysema progresses through dilation of alveolar ducts with retraction of alveolar walls. We also detected significant
disease heterogeneity across the lung and suggest that these patterns can provide important insights into disease phenotypes and are valuable for monitoring
disease progression and regression.
2536. Golden Angle Radial Imaging for Improved Visualisation of Initial Stages of Inhalation in Dynamic
3 He Lung MRI
Helen Marshall 1 , Salma Ajraoui 1 , James M. Wild 1
1 Academic Unit of Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
The study of ventilation dynamics with hyperpolarised 3 He requires a fast imaging sequence to capture the flow of contrast into the lungs. Radial
acquisition, among other sequences, has previously been demonstrated for this purpose. However, images from a standard radial acquisition are constrained
to a fixed resolution determined at the acquisition stage. Here golden angle radial sampling was used to image the inhalation of hyperpolarised 3 He and
compared to a standard, sequential radial acquisition. Golden angle radial imaging enabled reconstruction of the dynamic dataset at any chosen spatiotemporal
resolution, providing improved visualisation of the initial stages of inhalation.
2537. On the Relationship Between 3He ADC and Lung Morphometrical Parameters
Alexander L. Sukstanskii 1 , James D. Quirk 1 , Jason C. Woods 1,2 , David S. Gierada 1 , Barbara A. Lutey 3 ,
Mark S. Conradi 2 , Dmitriy A. Yablonskiy 1,2
1 Radiology, Washington University, St. Louis, Misssouri, United States; 2 Physics, Washington University, St. Louis, MO, United
States; 3 Internal Medicine, Washington University, St. Louis, MO, United States
The apparent diffusion coefficient (ADC) of hyperpolarized 3He gas in lungs increases in emphysema and can serve as a biomarker of the disease
progression. It is not clear, however, how ADC relates to lung microstructure. In the present communication, using 3He-based in vivo lung morphometry
technique, we demonstrate that ADC and a standard histological parameter – mean chord length (Lm) reflect lung microstructure parameters in different
ways. As a result, a there is no unique relationship between ADC and Lm. At the same time, 3He-based lung morphometry allows quantification of the lung
microstructure in terms of Lm, surface-to-volume ratio and other standard histological parameters.
2538. Modelling Non-Gaussian 3He Diffusion Signal Behaviour Using a Fractional Dynamics Approach
Juan Parra-Robles 1 , Salma Ajraoui 1 , Jim M. Wild 1
1 University of Sheffield, Sheffield, United Kingdom
Diffusion of 3He gas in the lung has been shown to deviate from Gaussian behaviour. Cylinder model and diffusional kurtosis have been previously used to
quantify non-Gaussian signals. In this work the diffusion stretched-exponential model is used as a new approach to model the non-Gaussian behaviour. The
results obtained demonstrate that the anomalous diffusion stretched-exponential model fits well the behaviour of the 3He lung MR signal. This model can
potentially provide valuable information about lung microstructure at different length scales.
2539. Experimental Investigation of the Limits of Validity of the Physical Basis of a Method for in Vivo Lung
Morphometry with 3 He Diffusion MRI
Juan Parra-Robles 1 , Salma Ajraoui 1 , Martin H. Deppe 1 , Steven R. Parnell 1 , Jim M. Wild 1
1 Unit of Academic Radiology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
In this work, the limits of validity of physical basis of a model of 3 He MR lung diffusion are investigated experimentally in simple geometric models. The
experimental results have highlighted limitations of the cylinder model. Breakdown of the Gaussian phase approximation was experimentally demonstrated
for gradient strengths commonly used in lung ADC experiments, as the localized diffusion regime is approached. The physical assumptions of the cylinder
model are only valid if the localized diffusion regime and its neighboring intermediate regimes are avoided.