title: Acceleration of MR parameter mapping using annihilating filter-based low rank hankel matrix (ALOHA).
abstract: MR parameter mapping is one of clinically valuable MR imaging techniques. However, increased scan time makes it difficult for routine clinical use. This article aims at developing an accelerated MR parameter mapping technique using annihilating filter based low-rank Hankel matrix approach (ALOHA).
  
  
  
  When a dynamic sequence can be sparsified using spatial wavelet and temporal Fourier transform, this results in a rank-deficient Hankel structured matrix that is constructed using weighted k-t measurements. ALOHA then utilizes the low rank matrix completion algorithm combined with a multiscale pyramidal decomposition to estimate the missing k-space data.
  
  
  
  Spin-echo inversion recovery and multiecho spin echo pulse sequences for T1and T2mapping, respectively, were redesigned to perform undersampling along the phase encoding direction according to Gaussian distribution. The missing k-space is reconstructed using ALOHA. Then, the parameter maps were constructed using nonlinear regression.
  
  
  
  Experimental results confirmed that ALOHA outperformed the existing compressed sensing algorithms. Compared with the existing methods, the reconstruction errors appeared scattered throughout the entire images rather than exhibiting systematic distortion along edges and the parameter maps.
  
  
  
  Given that many diagnostic errors are caused by the systematic distortion of images, ALOHA may have a great potential for clinical applications. Magn Reson Med 76:1848-1864, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science & Technology (KAIST), 373-1 Guseong-dong Yuseong-gu, Daejon, 305-701, Republic of Korea.
authors.forename: Dongwook
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science & Technology (KAIST), 373-1 Guseong-dong Yuseong-gu, Daejon, 305-701, Republic of Korea.
authors.forename: Kyong Hwan
authors.initials: KH
authors.lastname: Jin
authors.affiliation: Department of Radiology, Gachon University Gil Medical Center, 21 Namdong-daero 774beon-gil, Namdong-gu, Incheon 21565, Republic of Korea.
authors.forename: Eung Yeop
authors.initials: EY
authors.lastname: Kim
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science & Technology (KAIST), 373-1 Guseong-dong Yuseong-gu, Daejon, 305-701, Republic of Korea.
authors.forename: Sung-Hong
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science & Technology (KAIST), 373-1 Guseong-dong Yuseong-gu, Daejon, 305-701, Republic of Korea.
authors.forename: Jong Chul
authors.initials: JC
authors.lastname: Ye
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: MR parameter mapping; annihilating filter; compressed sensing; low rank Hankel structured matrix completion; multiecho spin echo; spin echo inversion recovery