Contrast and spatial resolution in MREIT using low amplitude current. Phys Med Biol 2006 Oct 07;51(19):5035-49
Date
09/21/2006Pubmed ID
16985286DOI
10.1088/0031-9155/51/19/020Scopus ID
2-s2.0-33748932489 (requires institutional sign-in at Scopus site) 40 CitationsAbstract
Magnetic resonance-electrical impedance tomography employs low amplitude currents injected or induced inside an object. The additional magnetic field due to these currents results in a phase in the MR images. In this study, a modified fast spin-echo sequence was used to measure this magnetic field, which is obtained by scaling the MR phase image. A finite element method with first order triangular elements was used for the solution of the forward problem. An iterated sensitivity matrix-based algorithm was developed for the inverse problem. The resulting ill-conditioned matrix equation was regularized using the Tikhonov method and solved using a conjugate gradient solver. The spatial and contrast resolution of the technique was tested using agarose gel phantoms. A circular phantom with 7 cm diameter and 1 cm thickness is used in the phantom experiments. The amplitude of the injected current was 1 mA. 3, 5 and 8 mm diameter insulators and high conductor objects are used for the spatial resolution study and an average full-width half-maximum value of 4.7 mm is achieved for the 3 mm insulator case. For the contrast analysis, the conductivity of a 15 mm object is varied between 44% and 500% with respect to the background and results are compared to the ideal reconstruction.
Author List
Birgul O, Hamamura MJ, Muftuler LT, Nalcioglu OAuthor
Lutfi Tugan Muftuler PhD Professor in the Neurosurgery department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AlgorithmsContrast Media
Electric Impedance
Gels
Humans
Image Enhancement
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Models, Statistical
Phantoms, Imaging
Sepharose
Sodium Chloride
Tomography, Emission-Computed
