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Code : 9345-350886 Created Date : Saturday, February 6, 2016 Visit : 1239

Computer Assisted Radiology and Surgery

The report of Computer Assisted Radiology and Surgery by Dr. Alireza Ahmadian

Application Code :

306-0215-0094

Created Date : Monday, June 22, 2015 14:53:40Update Date : Monday, January 11, 2016 14:06:41
IP Address : 192.168.58.229Submit Date : Wednesday, September 23, 2015 15:35:33Email :ahmadian@sina.tums.ac.ir

Personal Information

Name :	Alireza
Surname :	Ahmadian
School/Research center :	School of Medicine
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Position :	Professor
Tel :	+21-889-91121

Information of Congress

Title of the Congress :	Computer Assisted Radiology and Surgery
Title of your Abstract :	Estimation of intraoperative brain shift by combination of stereovision and doppler ultrasound: phantom and animal model study
Destination Country :	Spain
From :	Wednesday, June 24, 2015
To :	Saturday, June 27, 2015
Abstract(Please copy/paste the abstract send to the congress) :	Abstract Purpose Combination of various intraoperative imaging modalities potentially can reduce error of brain shift estimation during neurosurgical operations. In the present work, a new combination of surface imaging and Doppler US images is proposed to calculate the displacements of cortical surface and deformation of internal vessels in order to estimate the targeted brain shift using a Finite Element Model (FEM). Registration error in each step and the overall performance of the method are evaluated. Methods: The preoperative steps include constructing a FEM from MR images and extracting vascular tree from MR Angiography (MRA). As the first intraoperative step, after the craniotomy and with the dura opened, a designed checkerboard pattern is projected on the cortex surface and projected landmarks are scanned and captured by a stereo camera. This 3D point cloud should be registered to boundary nodes of FEM in the region of interest. For this purpose, we developed a new non-rigid registration method, called finite element drift that is more compatible with the underlying nature of deformed object. The presented algorithm outperforms other methods such as coherent point drift when the deformation is local or non-coherent. After registration, the acquired displacement vectors are used as boundary conditions for FE model. As the second step, by tracking a 2D Doppler ultrasound probe swept on the parenchyma, a 3D image of deformed vascular tree is constructed. Elastic registration of this vascular point cloud to the corresponding preoperative data results the second series of displacement vector applicable to closest internal nodes of FEM. After running FE analysis, the displacement of all nodes is calculated. The brain shift is then estimated as displacement of nodes in boundary of a deep target, e.g., a tumor. We used intraoperative MR (iMR) images as the references for measuring the performance of the brain shift estimator. In the present study, two set of tests were performed using: (a) a deformable brain phantom with surface data and (b) an alive brain of an approximately big dog with surface data and US Doppler images. In our designed phantom, small tubes connected to an inflatable balloon were considered as displaceable targets and in the animal model, the target w Results In the phantom study, the registration error for the surface points before FE analysis and for the target points after running FE model were<0.76 and 1.4mm,respectively. In a real condition of operating room for animal model, the registration error was about 1mm for the surface, 1.9mm for the vascular tree and 1.55mm for the target points. Conclusions: The proposed projected surface imaging in conjunction with the Doppler US data combined in a powerful biomechanical model can result an acceptable performance in calculation of deformation during surgical navigation. However, the projected landmark method is sensitive to ambient light and surface conditions and the Doppler ultrasound suffers from noise and 3D image construction problems, the combination of these two methods applied on a FEM has an eligible performance.
Keywords of your Abstract :	FED registration method · CPD · Finite Element Model · Projected landmarks · Doppler ultrasound Target registration error
Acceptance Letter :	http://gsia.tums.ac.ir/images/UserFiles/25202/Forms/306/CARS 2015 Acceptance_1.pdf
The presentation :	Poster
The Cover of Abstract book :	http://gsia.tums.ac.ir/images/UserFiles/25202/Forms/306/Pages_from_10_1007_s11548-015-1216-z.pdf
Published abstract in the abstract book with the related code :	http://gsia.tums.ac.ir/images/UserFiles/25202/Forms/306/10.1007_s11548-015-1216-z_2.pdf
Where has your abstract been indexed? :	ISI
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The Congress Reporting Form

How many volunteers were present at the Congress? :	1000
Delegates from which countries presented in the congress? :	all countries mainly European, American and Asian Germany, Spain, UK, Turkey, Italy, China, France
Were the delegates of any other organizations present in the congress? :	Yes
If yes, please write the names of the organizations in the box :	ISCAS, CAR, CAD and CMI organizations
What were the responses to your talking points? Were specific questions or concerns raised? :	Yes, I found the topic interested for some researchers in the field Since our work was a new approach for brain shift modelling during image guide navigation there were questions on whether we have managed to implement this work in our developed navigation system. The work was done on a phantom and animal study and we are approaching to implement it for Human
If you met staff members, please list their full names & positions. :	I met some faculty members of my previous university
Please inform us if there are any follow up actions we need to talk with the members of the congress :	I have had some contacts with Professors and I will inform you for further steps. Among them, Prof. Navab who has been working with us since 2006 could be a good choice. He is very busy and hardly responses to email We have already had experiences of collaboration with him under DAAD scheme in Germany. We both are interested in setting up a new collaboration scheme for new approaches in Image guided surgery systems. He has agreed to go ahead with submission of a new proposal. I hope we can proceed this time as we already did in 2006 with success.
Your experiences about the travel processes(Providing ticket, accommodation,...) :	Quite tough, in particular visa process which is a headache!
Please give a briefing of your own observations and outcomes of the congress: :	The CARS congress founded in 1985 has played a leading role in medical and imaging informatics for more than 25 years. They have focused on research and development on novel algorithms and systems and their applications in radiology and surgery. In this conference one has the opportunity to meet scholars and experts in the multi-diciplenary fields of radiology, surgery fused with engineering, informatics and healthcare management. Their topics of interest are image- and model-guided interventions, intelligent operating room of the future, decision and action support in surgical management, computer aided diagnosis, surgical navigation and robotics.

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