Pramod Prabhakar Rao, Presenter: Nothing to Disclose

Mingde Lin PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Nikhil Bhagat MD, Abstract Co-Author: Nothing to Disclose

Dirk Schäfer, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Romaric Loffroy, Abstract Co-Author: Nothing to Disclose

Olivier Pellerin MD, MSc, Abstract Co-Author: Nothing to Disclose

Niels Noordhoek PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Peter G Eshuis PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Alessandro Guido Radaelli PHD, MS, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Eleni A. Liapi MD, Abstract Co-Author: Research grant, ContextVision AB

Michael Grass PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Jean-Francois H. Geschwind MD, Abstract Co-Author: Consultant, Biocompatibles International plc Consultant, Bayer AG Consultant, Guerbet SA Consultant, Nordion, Inc Grant Support, Biocompatibles International plc Grant Support,Genentech, Inc Grant Support, Bayer AG Grant Support, Koninklijke Philips Electronics NV Grant Support, Nordion, Inc Grant Support, ContextVision AB Grant Support, CeloNova BioSciences, Inc Founder, PreScience Labs, LLC CEO, PreScience Labs, LLC

In our institution, translational interventional research is performed in the VX2 rabbit liver tumor model using commercial C-arm systems (Allura FD20 with XperCT, Philips Healthcare, Best, Netherlands). Small physical size and rapid cardio-ventilatory motion in the rabbit poses a challenge in producing adequate imaging. We seek to improve cone beam CT (CBCT) image quality (IQ) by improving x-ray techniques, 3D reconstruction, and motion compensation.

3 adult male New Zealand white rabbits, one rabbit non-tumor bearing (C) and two experimental rabbits (R1) and (R2) had implanted tumors. Following commercially available x-ray techniques and image acquisition parameters were used to scan rabbit (C) at 120kVp to determine the best IQ: (1) 200mA, 5ms, 30 frames per second (fps), 10 sec scan time (st) (Fig C(a)), (2) 150mA, 5ms, 60 fps, 5 st (Fig C(c)), and (3) 100mA, 5ms, 60fps, 10st (Fig C(b)). IQ was assessed based on image contrast, artifacts, and tumor delineation. R1 was imaged immediately after transarterial chemoembolization (TACE) and post-mortem using 120kVp, 150mA, 5ms, 60fps. R2 was imaged after TACE using a prototype x-ray technique (77kVp, 85mA, 5ms, 60fps, 5st; Fig C(d)). Images acquired from R1(a) and R2(a) were reconstructed: (1) using the commercially available filtered back projection kernel with prototype motion compensation (Fig R1&2 (b)), and (2) using a higher spatial resolution kernel with motion compensation (Fig R1&2 (c)). These images were compared to the post mortem images (R1(d)).  

The 120KVp, 150mA, 5ms, 60fps was the best among the commercially available protocols (R1(a)). The prototype x-ray technique and 3D reconstruction kernels showed even better IQ (Fig R2(a) and R1&2(c), respectively). Improvements to motion artifacts further improved IQ. Tumors were more clearly visualized after stages of improvement in image acquisition, 3D reconstruction, and motion compensation (Fig arrows).

Improvements in image acquisition protocol, 3D reconstruction, and motion compensation produced better IQ that allowed for better tumor delineation and characterization. This further enables use of clinical C-arm systems for translational, pre-clinical studies.

Optimization of imaging protocols in the rabbit liver tumor model will help to improve image quality in commercial machines.

Rao, P, Lin, M, Bhagat, N, Schäfer, D, Loffroy, R, Pellerin, O, Noordhoek, N, Eshuis, P, Radaelli, A, Liapi, E, Grass, M, Geschwind, J, Improving C-arm Cone Beam CT: Protocol Optimization and Reducing Motion Artifacts for Preclinical Imaging.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016853.html