ORIGINAL RESEARCH n NEURORADIOLOGY Radiology: Volume 283: Number 2—May 2017 n radiology.rsna.org 515 1 From the Neuroimaging Research Unit (S.G., F.A., S.B., E.C., D.G., M.F.) and Department of Neurology (M.F.), Insti- tute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Via Olgettina 60, 20132 Milan, Italy; Clinic of Neurology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia (E.S., T.S., I.S., V.S., V.S.K.); Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands (M.P.v.d.H.); and Biostatistics Unit, IRCCS-Ospedale Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy (M.C.). Received February 3, 2016; revision requested April 19; revision received August 3; accepted May 25; final version accepted September 1. Address correspondence to M.F. (e-mail: filippi.massimo@hsr.it ). Supported by Ministry of Education and Science, Republic of Serbia (ON175095) and Ministero della Salute (GR091577482). q RSNA, 2016 Purpose: To investigate the structural brain connectome in patients with Parkinson disease (PD) and mild cognitive impair- ment (MCI) and in patients with PD without MCI. Materials and Methods: This prospective study was approved by the local ethics committees, and written informed consent was obtained from all subjects prior to enrollment. The individual struc- tural brain connectome of 170 patients with PD (54 with MCI, 116 without MCI) and 41 healthy control subjects was obtained by using deterministic diffusion-tensor trac- tography. A network-based statistic was used to assess structural connectivity differences among groups. Results: Patients with PD and MCI had global network alterations when compared with both control subjects and patients with PD without MCI (range, P = .004 to P = .048). Rel- ative to control subjects, patients with PD and MCI had a large basal ganglia and frontoparietal network with decreased fractional anisotropy (FA) in the right hemi- sphere and a subnetwork with increased mean diffusivity (MD) involving similar regions bilaterally (P , .01). When compared with patients with PD without MCI, those with PD and MCI had a network with decreased FA, including basal ganglia and frontotemporoparietal regions bilater- ally (P , .05). Similar findings were obtained by adjusting for motor disability (P , .05, permutation-corrected P = .06). At P , .01, patients with PD and MCI did not show network alterations relative to patients with PD without MCI. Network FA and MD values were used to differen- tiate patients with PD and MCI from healthy control sub- jects and patients with PD without MCI with fair to good accuracy (cross-validated area under the receiver operat- ing characteristic curve [principal + secondary connected components] range, 0.75–0.85). Conclusion: A disruption of structural connections between brain areas forming a network contributes to determine an altered in- formation integration and organization and thus cognitive deficits in patients with PD. These results provide novel information concerning the structural substrates of MCI in patients with PD and may offer markers that can be used to differentiate between patients with PD and MCI and patients with PD without MCI. q RSNA, 2016 Online supplemental material is available for this article. Sebastiano Galantucci, MD Federica Agosta, MD, PhD Elka Stefanova, MD Silvia Basaia, MSc Martijn P. van den Heuvel, PhD Tanja Stojkovic ´, MD Elisa Canu, PhD Iva Stankovic ´, MD Vladana Spica, MD Massimiliano Copetti, PhD Delia Gagliardi, MD Vladimir S. Kostic ´, MD Massimo Filippi, MD Structural Brain Connectome and Cognitive Impairment in Parkinson Disease 1 This copy is for personal use only. To order printed copies, contact reprints@rsna.org