Sarah Svenningsen BSC, Presenter: Nothing to Disclose

Miranda Kirby PhD, Abstract Co-Author: Nothing to Disclose

Stephen Choy MD, Abstract Co-Author: Nothing to Disclose

Andrew Wheatley, Abstract Co-Author: Nothing to Disclose

David McCormack MD, Abstract Co-Author: Nothing to Disclose

Grace Parraga PhD, Abstract Co-Author: Nothing to Disclose

Pulmonary functional imaging using hyperpolarized 3He magnetic resonance imaging (MRI) provides a way to map heterogeneous ventilation abnormalities that are regionally and temporally persistent in asthma. Bronchial thermoplasty is a novel asthma treatment that aims to reduce smooth muscle mass in the lobar and segmental bronchi, with the goal being improved symptoms and asthma control. Currently, treatment is not guided by imaging to specific airway abnormalities. The purpose of this study was to exploit the image-guidance potential of 3He MRI by developing lung function maps that spatially identify airway abnormalities in asthma.

For a severe asthmatic, temporally persistent ventilation defects were observed on two visits 8 months apart after thermo-ablation therapy was completed. To improve the efficacy of thermoablation and decrease treatment time and cost, we investigated the potential for temporal-spatial lung function maps to guide therapy in asthmatics (n=7, 28±9 yr) who were evaluated using hyperpolarized 3He MRI three times, 7±2 days apart. Temporal maps were generated from ventilation images acquired on three occasions by co-registering 3He MRI after segmenting 3He voxel intensities using a modified k-means cluster algorithm. Corresponding, co-registered voxels were classified as 1) persistent defect, 2) intermittent defect, 3) partial ventilation, and, 4) persistent ventilation. The temporal map was registered to thoracic CT to enable structure-function comparisons and help guide therapy to specific ventilation defects.

We present a 3He MRI temporal-spatial lung function map co-registered to a CT-derived airway tree for a single asthmatic.  Regions-of-interest (ROI) were identified with persistent and intermittent defects as appropriate targets for treatment, whereas ROI with partial or full ventilation were also identified as regions that should be avoided.

Personalized temporal-spatial lung function maps of asthma can be generated to display functional abnormalities observed over time and to guide localized therapy.

Temporal-spatial lung function maps identified spatially and temporally persistent ventilation defects and the airways that lead to them as potential targets for thermo-ablation.

Svenningsen, S, Kirby, M, Choy, S, Wheatley, A, McCormack, D, Parraga, G, Hyperpolarized ³He Magnetic Resonance Imaging Temporal-spatial Maps of Asthma to Guide Endobronchial Thermo-ablation.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13020527.html