Gender	Male
E-mail	isak.prohovnik@mssm.edu
Education and Training	B.A., Tel Aviv University
	M.Sc. , Lund University
	Ph.D. , Lund University
	Post Doctoral Training , Yale University

Education and Training	B.A., Tel Aviv University
	M.Sc. , Lund University
	Ph.D. , Lund University
	Post Doctoral Training , Yale University

Research

Specific Clinical/Research Interest:
Functional & structural neuroimaging; CJD; AD; ESRD
Current Students: Ilana Seror
Postdoctoral Fellows: Hedok Lee
Overview:

Dr. Prohovnik serves as Professor of Psychiatry and Radiology at the Mount Sinai School of Medicine.
Summary of Research Studies:
Our research is focused at the conjunction of novel neuroimaging technology and itsapplication to clinical neuroscience. In particular, we apply novel MRI methods and quantitative image analysis, in conjunction with other physiological and clinical data, towards the understanding of degenerative and vascular dementias. Some of our work has also involved Sickle-Cell disease, personality disorders and normal aging. Currently, our two central projects are in Creutzfeldt-Jakob disease (CJD) and End-Stage Renal Disease (ESRD). Prion diseases are unique in their biology, and present new scientific and public health challenges. They have been very difficult to study in humans, due to their low prevalence, extremely virulent course, and molecular heterogeneity. CJD is the most common human prion disease. We have designed a study that, for the first time, allows investigation of the early stages of the disease, as well as the premorbid brain before disease onset, in relatively large and homogenous samples. Diffusion-weighted MRI currently offers the best sensitivity for detection of prion-associated cerebral lesions. In early-stage patients, we are defining the circuit of basal ganglia and thalamic structures affected by the disease. Interacting with cortical and cerebellar areas, this circuit may be associated with the clinical phenotype of the disease in several variants. In healthy subject! s, diffusion abnormalities in this circuit may be detectible years before onset of the disease. ESRD is known to be associated with cognitive deficits and cerebral atrophy, but their mechanisms are obscure. We are investigating cerebrovascular dysregulation in such patients by MRI, together with measurements of cerebral oxygenation (by Near-Infrared Spectroscopy) and carotid Blood Flow (by a quantitative Doppler technique). We have confirmed previous reports of cerebral atrophy, and are investigating its precise location. We have also found strong evidence for reductions of cerebral perfusion and oxygenation, which seem related to cognitive deficits. Notably, it appears that different types of dialysis treatment have different effects on cerebrovascular and cognitive function. Such findings may lead to improved treatment and outcome in these patients, which present significant public health challenges.

Our research is focused at the conjunction of novel neuroimaging technology and its application to clinical neuroscience. In particular, we apply novel MRI methods and quantitative image analysis, in conjunction with other physiological and clinical data, towards the understanding of degenerative and vascular dementias. Some of our work has also involved Sickle-Cell disease, personality disorders and normal aging.
Currently, our two central projects are in Creutzfeldt-Jakob disease (CJD) and End-Stage Renal Disease (ESRD). Prion diseases are unique in their biology, and present new scientific and public health challenges. They have been very difficult to study in humans, due to their low prevalence, extremely virulent course, and molecular heterogeneity. CJD is the most common human prion disease. We have designed a study that, for the first time, allows investigation of the early stages of the disease, as well as the premorbid brain before disease onset, in relatively large and homogenous samples. Diffusion-weighted MRI currently offers the best sensitivity for detection of prion-associated cerebral lesions. In early-stage patients, we are defining the circuit of basal ganglia and thalamic structures affected by the disease. Interacting with cortical and cerebellar areas, this circuit may be associated with the clinical phenotype of the disease in several variants. In healthy subjects, diffusion abnormalities in this circuit may be detectible years before onset of the disease.
ESRD is known to be associated with cognitive deficits and cerebral atrophy, but their mechanisms are obscure. We are investigating cerebrovascular dysregulation in such patients by MRI, together with measurements of cerebral oxygenation (by Near-Infrared Spectroscopy) and carotid Blood Flow (by a quantitative Doppler technique). We have confirmed previous reports of cerebral atrophy, and are investigating its precise location. We have also found strong evidence for reductions of cerebral perfusion and oxygenation, which seem related to cognitive deficits. Notably, it appears that different types of dialysis treatment have different effects on cerebrovascular and cognitive function. Such findings may lead to improved treatment and outcome in these patients, which present significant public health challenges.

Prohovnik I, Hurlet A, Adams R, De Vivo D, Pavlakis SG. Hemodynamic Etiology of Elevated Flow Velocity and Stroke in Sickle Cell Disease. JCBFM 2009; In Press.

Cohen OS, Hoffmann C, Lee H, Chapman J, Fulbright RK, Prohovnik I. MRI Detection of the Cerebellar Syndrome in Creutzfeldt-Jakob Disease. The Cerebellum 2009; In Press.

Koenigsberg HW, Siever LJ, Lee H, Guo X, New AS, Goodman M, Cheng H, Prohovnik I. Cerebral Processing of Negative Emotion in Borderline Personality Disorder. Psychiatry Research NeuroImaging 2009; In Press.

Fulbright RK, Hoffmann C, Lee H, Pozamantir A, Chapman J, Prohovnik I. MR imaging of familial Creutzfeldt-Jakob disease: A blinded and controlled study. American Journal of Neuroradiology; in press 2008; In Press.

Lee H, Prohovnik I. Brain parenchymal volume comparison between SPM5 and SIENAX. Psychiatry Research NeuroImaging; in press 2008; In Press.

Prohovnik I, Post J, Uribarr J, Lee H, Sandu O, Langhoff E. Cerebrovascular effects of hemodialysis in chronic kidney disease. JCBFM 2007; 27: 1861-1869.

Fulbright RK, Kingsley PB, Guo X, Hoffmann C, Kahana E, Chapman JC, Prohovnik I. The imaging appearance of Creutzfeldt-Jakob disease caused by the E200K mutation. Magnetic Resonance Imaging 2006; 24: 1121-1129.

Prohovnik I, Perl DP, Davis KL, Libow L, Lesser G, Haroutunian V. Dissociation of neuropathology from severity of dementia in late-onset Alzheimer disease. Neurology 2006; 66: 49-55.

Prohovnik I, Skudlarski P, Fulbright RK, Gore JC, Wexler BE. fMRI Changes before and after onset of reported emotions. Psychiatry Research NeuroImaging 2004; 132: 239-250.

Prengler M, Pavlakis SG, Prohovnik I, Adams RJ. Sickle cell disease: the neurological complications. Ann Neurol 2002 May; 51(5): 543-552.