title: White matter microstructural characteristics in Bipolar I and Bipolar II Disorder: A diffusion tensor imaging study.
abstract: BACKGROUND
  Diffusion tensor imaging (DTI) studies of bipolar disorder (BD) report contrasting results and are mainly focused on bipolar I (BD-I) samples. We aimed at investigating how and where DTI parameters differ between BD-I and bipolar II (BD-II) and between BD and healthy control subjects (HC).
  
  
  METHODS
  We conducted a tract-based spatial statistics analysis of DTI derived parameters, namely fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD) in a matched sample of 50 BD (25 BD-I and 25 BD-II) during the chronic course of the illness and 50 HC.
  
  
  RESULTS
  Compared to BD-I and HC, BD-II showed lower FA but no significant AD or RD differences in the right inferior longitudinal fasciculus (ILF). Both patient groups showed lower AD and RD in the left internal capsule and lower AD across the left ILF, the cortico-spinal tract within the right hemisphere and bilaterally in the cerebellum with respect to HC.
  
  
  CONCLUSIONS
  Patients were medicated at the time of scanning; the BD-II group had higher Hamilton Rating Scale for Depression scores than the BD-I group.
  
  
  CONCLUSIONS
  BD-II patients differ from BD-I in the ILF. Both BD subtypes showed widespread white matter (WM) changes in the internal capsule, cortico-spinal tract and cerebellum. The loss of WM integrity in BD-II might be due to demyelination whereas WM changes common to both subgroups could be attributable to axonal damage.
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; NESMOS Department, Sapienza University of Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Ambrosi
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Systems Medicine, "Tor Vergata" University, Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Chiapponi
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; NESMOS Department, Sapienza University of Rome, Italy; Centro Lucio Bini, Rome, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Sani
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; NESMOS Department, Sapienza University of Rome, Italy; Centro Lucio Bini, Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Manfredi
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Piras
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Neuroscience, "Tor Vergata" University, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Caltagirone
authors.affiliation: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Beth K. and Stuart C. Yudofsky Division of Neuropsychiatry, Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA. Electronic address: g.spalletta@hsantalucia.it.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Spalletta
mesh_terms: D016880:Anisotropy; D001714:Bipolar Disorder / Q000473:pathology*; D016022:Case-Control Studies; D002531:Cerebellum / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D011712:Pyramidal Tracts / Q000473:pathology*; D066127:White Matter / Q000473:pathology*
keywords: Bipolar Disorder, type I; Bipolar Disorder, type II; Diffusion tensor imaging; White matter integrity