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Methods, Apparatus, and Computer Readable Mediums for Performing Perfusion Studies

詳細技術說明

Dr. Ge WangMethods, Apparatus, and Computer Readable Mediums for Performing Perfusion Studieshttp://www.imaging.sbes.vt.edu

*Abstract

Background:

              

Perfusion studies in the human body have rapidly become an effective method in the diagnosis and treatment of such ailments as strokes, cancer, and heart diseases. One such method, CT perfusion, involves the injection of a bolus constraint into a blood vessel within proximity of a targeted organ, and then quantifying the resulting data as it travels into the organ. For example, in CT head profusion imaging collect such parameters as mean transit time (MTT), cerebral blood volume (CBV), and cerebral blood flow (CBF). However, the greatest limitation in CT perfusion imaging is the patient risk of exposure to high dosages of X-rays during scanning. Furthermore, efforts to reduce the dosages have decreased the signal to noise ratios and in turn resulted in poor image quality. Researchers at the University of Iowa have achieved alternative scanning methods that successfully reduce the dosage level without reducing image quality.

Technology:

                          

The widely accepted method of X-ray dose reduction in CT perfusion is to reduce the X-ray tube current. The drawback is that this increases the resulting noise level of the measured projection data. Research at the University of Iowa has led to the development of a method that uses a controllable apparatus to achieve a fractional scanning protocol and prediction algorithms that address incomplete projection data issues. The Partial Scan Protocols (PSP) works by maintaining high milliamperage setting while only collecting a fraction of the typical 360-degree dataset. The missing portion of the data set is predicted, based on a priori knowledge that as the bolus medium propagates through the body its concentration within a given organ decreases at a predictable rate gradually over time. This is important because the differences between one fractional scan from another is trivial. The missing portion is then estimated from the known projection of the same geometry using a Projection Interpolation Algorithm. However, there are instances where the interpolation process can introduce projection errors or bias. To overcome this, the PSP projection images can also be reconstructed using an Image Prediction Algorithm (IPA) which uses a full scan image as its baseline, and then extrapolates data based on this image to predict the missing portions from the PSP fractional scan. Both methods produce high resolution perfusion images that are reconstructed at a fraction of the nominal radiation dose.

Advantages:

                      

HIGH SIGNAL TO NOISE RATIO: Typically reducing the milliamperage level reduces the X-ray dosage. This in turn increases the data noise and degrades the perfusion image. By reducing the fractional scan, the milliamperage is allowed to remain at high levels without lowering the signal to noise ratio.

LOW X-RAY DOSAGE: As with all CT modalities there is a risk of cancer due to high levels of radiation exposure. The technology is an example of methods being implemented to reduce this risk.

             

Patent Link:

                   
Methods, Apparatus, and Computer Readable Mediums for Performing Perfusion Studies; www.google.com/patents/US6934353

Relevant Research:

                 
Hsieh J, Wei YC, Wang G: Fractional Scan Algorithms for Low-Dose CT Perfusion. Medical Physics 31:1254-1257, 2004

           
This and other relevant papers can be downloaded at: http://www.imaging.sbes.vt.edu/publications

*Licensing

Catherine S. Koh, AB, MBALicensing ManagerUniversity of Iowa Research FoundationPhone: (319) 335-4659 Email: catherine-koh@uiowa.edu

國家/地區

美國