Herwin Speckter, Presenter: Nothing to Disclose

Rafael Fermin, Abstract Co-Author: Nothing to Disclose

Pedro Roa, Abstract Co-Author: Nothing to Disclose

Bernd Foerster, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Peter Stoeter, Abstract Co-Author: Nothing to Disclose

To report some unusual MR findings in a large group of patients with PKAN (formerly Hallervorden-Spatz disease).

We examined 20 patients with dystonia of a rather late onset type and 1 preclinical case showing the typical MR changes (“tiger's eye”) and compared these findings to 14 non-affected volunteers. Homozygous mutation of the PANK2 gene has been proven in all cases (A. Rolfs, Albrecht-Kossel-Institute, Rostock/Germany). MR Examinations were carried out on a 3T Achieva scanner (Philips) and included T2 time calculation and Diffusion Tensor Imaging (DTI) with gradient application in 32 directions.  

All patients showed the typical signal reduction and reduction of T2 time within the pallidum and the medial parts of the subthalamic nucleus due to deposits of iron. This finding was highly significant (p<0.0001). In DTI we saw an increase of fractional anisotropy (FA) in the pallidum, but without an accompanying reduction of the apparent diffusion coefficient (ADC) which might be explained by the severely disturbed susceptibility due to the highly inhomogeneous iron distribution in our patients. In addition, FA was reduced and ADC increased in the anterior part of the internal capsule indicating some damage to the fronto-basal white matter tracts, but otherwise, DTI parameters appeared to be within normal limits. A surprising finding was the absence of the bright spot (tiger eye) in the medial part of the iron deposit within the pallidum in 6 patients. Those without the bright spot were slightly older whereas the preclinical case showed the bright spot. There was no obvious difference in onset or clinical expression of the disease.  

The absence of the “tiger's eye” is known from atypical PKAN cases but has been reported rarely in carriers of typical PANK2 mutations (Zolkipli et al., Paediatr Radiol 2006, 36: 1329). According to our findings, it might be due to a secondary severe accumulation of iron in the pallidum with obscuration of the bright spot which obviously represents the primary lesion.

The relatively well preserved white matter encourages efforts to invest into curative strategies.

Speckter, H, Fermin, R, Roa, P, Foerster, B, Stoeter, P, Unusual MR Findings in a Large Group of Patients with Pantothenate Kinase-associated Neurodegeneration (PKAN).  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013366.html