title: Hemodynamic segmentation of brain perfusion images with delay and dispersion effects using an expectation-maximization algorithm.
abstract: Automatic identification of various perfusion compartments from dynamic susceptibility contrast magnetic resonance brain images can assist in clinical diagnosis and treatment of cerebrovascular diseases. The principle of segmentation methods was based on the clustering of bolus transit-time profiles to discern areas of different tissues. However, the cerebrovascular diseases may result in a delayed and dispersed local perfusion and therefore alter the hemodynamic signal profiles. Assessing the accuracy of the segmentation technique under delayed/dispersed circumstance is critical to accurately evaluate the severity of the vascular disease. In this study, we improved the segmentation method of expectation-maximization algorithm by using the results of hierarchical clustering on whitened perfusion data as initial parameters for a mixture of multivariate Gaussians model. In addition, Monte Carlo simulations were conducted to evaluate the performance of proposed method under different levels of delay, dispersion, and noise of signal profiles in tissue segmentation. The proposed method was used to classify brain tissue types using perfusion data from five normal participants, a patient with unilateral stenosis of the internal carotid artery, and a patient with moyamoya disease. Our results showed that the normal, delayed or dispersed hemodynamics can be well differentiated for patients, and therefore the local arterial input function for impaired tissues can be recognized to minimize the error when estimating the cerebral blood flow. Furthermore, the tissue in the risk of infarct and the tissue with or without the complementary blood supply from the communicating arteries can be identified.
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.
authors.forename: Chia-Feng
authors.initials: CF
authors.lastname: Lu
authors.forename: Wan-Yuo
authors.initials: WY
authors.lastname: Guo
authors.forename: Feng-Chi
authors.initials: FC
authors.lastname: Chang
authors.forename: Shang-Ran
authors.initials: SR
authors.lastname: Huang
authors.forename: Yen-Chun
authors.initials: YC
authors.lastname: Chou
authors.forename: Yu-Te
authors.initials: YT
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D001921:Brain / Q000098:blood supply* / Q000473:pathology*; D002343:Carotid Artery, Internal / Q000473:pathology; D016893:Carotid Stenosis / Q000175:diagnosis; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D009072:Moyamoya Disease / Q000175:diagnosis; D055420:Perfusion Imaging / Q000379:methods*; D055815:Young Adult
references.citation: Magn Reson Med. 2006 May;55(5):1180-5
references.pmid: 16598717
references.citation: Magn Reson Med. 1996 Nov;36(5):726-36
references.pmid: 8916023
references.citation: Acta Radiol. 1995 Sep;36(5):520-8
references.pmid: 7640098
references.citation: Magn Reson Med. 2007 Jan;57(1):181-91
references.pmid: 17191233
references.citation: Magn Reson Med. 2000 Sep;44(3):466-73
references.pmid: 10975900
references.citation: Radiology. 1996 Nov;201(2):405-12
references.pmid: 8888232
references.citation: Magn Reson Med. 2003 Jul;50(1):164-74
references.pmid: 12815691
references.citation: Stroke. 2007 Dec;38(12):3158-64
references.pmid: 17975106
references.citation: PLoS One. 2011;6(9):e25621
references.pmid: 21980508
references.citation: Med Image Anal. 2007 Jun;11(3):242-53
references.pmid: 17433760
references.citation: Circ Res. 1965 Apr;16:309-21
references.pmid: 14270567
references.citation: Magn Reson Med. 1990 May;14(2):249-65
references.pmid: 2345506
references.citation: AJNR Am J Neuroradiol. 2004 Nov-Dec;25(10):1636-44
references.pmid: 15569724
references.citation: J Cereb Blood Flow Metab. 1999 Jul;19(7):701-35
references.pmid: 10413026
references.citation: PLoS One. 2010 Apr 26;5(4):e10331
references.pmid: 20436675
references.citation: Magn Reson Med. 2006 Jul;56(1):146-56
references.pmid: 16767744
references.citation: J Magn Reson Imaging. 1997 Jan-Feb;7(1):47-55
references.pmid: 9039593
references.citation: Magn Reson Med. 1996 Nov;36(5):715-25
references.pmid: 8916022
references.citation: Magn Reson Med. 2003 May;49(5):885-94
references.pmid: 12704771
references.citation: Magn Reson Imaging. 1996;14(2):157-62
references.pmid: 8847971
references.citation: Stroke. 2008 Jan;39(1):75-81
references.pmid: 18063829
references.citation: Radiology. 1994 Dec;193(3):637-41
references.pmid: 7972800
references.citation: J Neurol Neurosurg Psychiatry. 2007 May;78(5):485-91
references.pmid: 17056631