title: Pulse Sequence based Multi-acquisition MR Intensity Normalization.
abstract: Intensity normalization is an important preprocessing step in magnetic resonance (MR) image analysis. In MR images (MRI), the observed intensities are primarily dependent on (1) intrinsic magnetic resonance properties of the tissues such as proton density (PD), longitudinal and transverse relaxation times (T1andT2respectively), and (2) the scanner imaging parameters like echo time (TE), repeat time (TR), and flip angle (α). We propose a method which utilizes three co-registered images with different contrast mechanisms (PD-weighted, T2-weighted and T1-weighted) to first estimate the imaging parameters and then estimatePD,T1, andT2values. We then normalize the subject intensities to a reference by simply applying the pulse sequence equation of the reference image to the subject tissue parameters. Previous approaches to solve this problem have primarily focused on matching the intensity histograms of the subject image to a reference histogram by different methods. The fundamental drawback of these methods is their failure to respect the underlying imaging physics and tissue biology. Our method is validated on phantoms and we show improvement of normalization on real images of human brains.
authors.affiliation: Image Analysis and Communications Laboratory, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Amod
authors.initials: A
authors.lastname: Jog
authors.affiliation: Image Analysis and Communications Laboratory, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Snehashis
authors.initials: S
authors.lastname: Roy
authors.affiliation: Image Analysis and Communications Laboratory, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Carass
authors.affiliation: Image Analysis and Communications Laboratory, The Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Prince
keywords: brain; intensity normalization/standardization; magnetic resonance imaging; pulse sequence