Copyright (c) 2013 Jarmo T. Alander
Printed: Saturday the 16th February 2019 (Week 07)
ImageICGA for ClinICGA: Brain vein imaging
"Motivation comes deep from brain"
How to help neurosurgeons by doing
project works on automation?
Obs! Images shown here are links to more information (or source of the corresponding image).
Above image: (c) HUS
Operation of brain veins is highly demanding neurosurgery.
Intraoperational blood circulation monitoring is essential for good results.
Problems in blood circulation can cause serious neurological damage or even dead.
Image: (c) 2008 K. Koivuporras
Indocyanine green contrast agent
Intraoperational blood circulation monitoring is possible with a
chemical called indocyanine green (ICG), which
fluorescents in near-infrared (800nm).
It was long used in imaging of blood veins in eye
It is extremely harmless chemical that can be injected to blood circulation
- Illumination of object with NIR light (<800nm, lamp, laser, or NIR-LED)
- Filter out (Fs) wavelengths longer than the fluorescent wavelength from the illumination (if necessary)
- Filter out (Fc) illumination wavelenght from the image (before camera)
- Camera must be sensitive to NIR (without NIR-cutoff filter)
Image: (c) 2008 J. T. Alander
Benefits of fluorescent imaging:
- only, in principle, the parts containing ICG are seen in the image
- NIR-light penetrates deeper in tissue than visual light
- ICG is transitional in blood circulation (half lifetime only a couple of minutes)
- possible allegic reaction (contain small amount of iodine)
- a camera is needed for imaging (not bare eye)
- new in imaging blood circulation dynamics (excellent research topic!)
Image: (c) 2008 K. Koivuporras
Near-Infra Red (NIR), (IR-A)
is light that is not visible to human eye.
It behaves optically very similarly to visible light (optical lenses etc function well).
Silicon sensors are usually sensitive to NIR like
most digital cameras.
Petri's NIR-camera page
Image: (c) 2007-2008 P. Välisuo with a modified digital pocket camera.
Angiography = imaging of blood veins
Brain vein surgery is usually done with an operation microscope (binocular).
The latest operation microscopes have integrated fluorescent imaging system
that can be used to blood circulation monitoring intraoperationally.
The microscope image (video) can be recorded for later analysis and documentation.
Image: (c) C. Zeiss
The method to use ICG in neurosurgical angiography was presented by
A. Raabe et al:
- A. Raabe, P. Nakaji, J. Beck. L. J. Kim, F. P. K. Hsu, J. D. Kamerman, V. Seifert and R. F. Spetzler,
Prospective evaluation of surgical microscope-integrated intraoperative
near-infrared indocyanine green videoangiography during aneurysm surgery,
Journal of Neurosurgery,
Vol. 103, pp. 982-989, 2005.
NIR video-angiography with surgical microscope (Zeiss).
SUMMER PROJECT WORK
movements and deformations disturb analysis of ICGA videos.
consecutive frames must be registered so that the corresponding parts are aligned properly.
The tasks are tailored to meet the summer traineer's skill profile.
Step by step
Here roughly what is expected:
- learning basics of ICGA
- learning basics of image registration
- learning ITK medical image processing system
- registration of ICGA videoframes
- if possible: registration of CT and ICGA
- behind the horizon: image registration online using FPGA
- making continuous reporting
Image: (c) 2007 J. Alander: chimney at Palosaari campus area
- Programming (e.g. Matlab) and especially
- basics of signal/image processing
help much in proceeding with this Summer task.
ITK is an open source software package for
medical image processing that can be
programmed/used with e.g.
Images: (c) www.itk.org
- image processing
- image registration
- user interfaces
- FPGA (real-time operation)
This project is a cooperation of several parties
- engineers: constructing machines and programs
- compnies: that produce machines and programs
- medical doctors: hopefully using what the above supply
- great audience: patients
- nationally (in Finland several universities)
- internationally (several universities)
University of Vaasa
Helsinki University of Technology