Dragos M. Vasilescu MS, Abstract Co-Author: Nothing to Disclose

Abhilash Kizhakke, Presenter: Nothing to Disclose

Guohua Cao, Abstract Co-Author: Nothing to Disclose

Otto Zhou PhD, Abstract Co-Author: Nothing to Disclose

Eric A. Hoffman PhD, Abstract Co-Author: Shareholder, VIDA Diagnostics, Inc Medical Advisory Board, Siemens AG

For the purpose of gaining further insights into the morphometry and morphology of the in vivo murine lung and heart, we introduce a combination of cardiac based triggering with existing intermittent iso-pressure breath holds for enhancing pulmonary and cardiac image quality when coupled with a newly developed carbon nano tube (CNT) based microCT (µCT) scanner (Charybdis III, Chapel Hill, NC). we are able to acquire projections with scan apertures which are short relative to the murine heart rate resulting in higher structural details and better contrast of lung parenchyma and vasculature.

A mouse (C57Bl/6, female, 7months old, 22g) was anaesthetized with I.P. ketamine/xylazine. Tracheostomy allowed for continuous ventilation at 130bpm after being paralyzed with pancuronium. Sedation was maintained using an Isoflurane/O2 mixture. A small animal ventilator (SAR-830, CWE Inc., Ardmore, PA) was modified to allow intermittent iso-pressure breath holds utilizing a secondary solenoid valve connected to the expiratory path controlled externally. The µCT scanner was triggered by a combined signal of the acquired cardiac signal (BioVet, M2M Imaging, Newark, NJ) and the ventilation signal. A novel CNT field emission micro-focus x-ray source was used with a scan aperture (pulse width) of 20ms at 50kV and 1.5mA; acquiring 400 projections over 200 degrees. A camera integration time of 300msec allowed efficient matching with a non-periodic trigger. Images were reconstructed at 512x512x512 with a voxel size of 75µm. An open source image processing software package (FIJI, http://pacific.mpi-cbg.de) was used for processing the image slices. Uniformly random sampled slice stacks were averaged to generate histograms of lung parenchyma. 

Based on both visual assessment as well as detail within the density histogram (see figure 1) of the lung fields, greater detail within the lung fields were achieve with cardiac gating coupled with the fast scan apertures provided by the CNT micro CT system. 

The presented technique provides for improved in vivo characterization of the murine lung.

The presented imaging modality will provide important information for the assessment of pathologic processes in the murine lung model.

Vasilescu, D, Kizhakke, A, Cao, G, Zhou, O, Hoffman, E, Short Scan Aperture Micro-CT Imaging Utilizing a Novel Carbon Nano Tube X-ray Source.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016368.html