Ashley Kempf Lotfipour MD, Presenter: Nothing to Disclose

Sam Wharton, Abstract Co-Author: Nothing to Disclose

Stefan Schwarz MD, Abstract Co-Author: Nothing to Disclose

Krishna Gontu MD, Abstract Co-Author: Nothing to Disclose

Andreas Schaefer PhD, Abstract Co-Author: Nothing to Disclose

Andrew Peters PhD, Abstract Co-Author: Nothing to Disclose

Richard Bowtell PhD, Abstract Co-Author: Nothing to Disclose

Dorothee P. Auer MD, Abstract Co-Author: Nothing to Disclose

Penny Anne Gowland PhD, Abstract Co-Author: Nothing to Disclose

Nin Bajaj PhD, Abstract Co-Author: Nothing to Disclose

Magnetic susceptibility is a more direct indicator of tissue iron content than other MR markers of iron. This paper presents the first quantitative, in vivo measurements of the susceptibility of the substantia nigra in patients with Parkinson’s disease.

Nine Parkinson’s disease (PD) patients and eleven controls were recruited. Subjects were defined as having tremor dominant PD (TDPD) or postural instability gait disorder (PIGD) according to the Queen Square Brain Bank Criteria. MRI scans were acquired using a 7T Philips Achieva MRI scanner, using T2* weighted, 3D, fast field echo sequences. Magnitude and phase images were reconstructed and susceptibility maps were created from phase images. Regions of interest (ROIs) were drawn around the substantia nigra (SN), red nucleus and pars compacta (PC) of the SN on modulus images and then applied to susceptibility maps. A region of interest was drawn in adjacent white matter as a control area. Susceptibility values were recorded from each whole ROI, and from sub regions within each ROI.

There was no significant difference between the age of the PD patients and control group (p=0.279). A significant difference was found between PD patients and normal control subjects for the PC susceptibility value (p=0.042) but not for the whole SN (p=0.176). This main effect in the PC was lost when age was controlled (p=0.08), although no significant effect of age was observed (p=0.30). There was a significant gradient in relative susceptibility of the SN between caudal and cranial slices for both PD and normal control subjects (p=0.001). The PD patients showed a steeper gradient but there was no significant between-group effect. The subregion analysis did not show significant anterior/posterior variation, although there was a trend for the anterior portion of the SN to show higher susceptibility than the posterior portion, suggesting an increased caudal/rostral and medial/lateral variation in PD.

The magnetic susceptibility of the pars compacta is increased in Parkinson's disease patients as compared to controls, corresponding to the expected increase in substantia nigral iron.

Susceptibility mapping, which provides the most direct measurement of tissue iron content, may be utilized as a novel tool for studying the development and pathology of Parkinson’s disease.

Lotfipour, A, Wharton, S, Schwarz, S, Gontu, K, Schaefer, A, Peters, A, Bowtell, R, Auer, D, Gowland, P, Bajaj, N, High-Resolution Magnetic Susceptibility of Substantia Nigra in Parkinson’s Disease.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11005913.html