Magnetic resonance imaging, susceptibility weighted imaging and quantitative susceptibility mapping findings of pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) is extremely rare. In this study, we aimed to evaluate the magnetic resonance imaging (MRI) findings of PKAN patients. Conventional MRI and susceptibility weighted imaging (SWI) sequences and quantitative susceptibility mapping (QSM) maps of six patients from three PKAN families and eight healthy male volunteers were retrospectively analyzed. Iron content was represented by QSM values. The typical eye-of-the-tiger sign (n = 4) and hyperintensity (n = 2) of the bilateral globus pallidus (GP) were observed on T2WI sequences. The SWI signal was low (n = 5), and the QSM values were obviously higher (n = 2), which manifested as a reversed eye-of-the-tiger sign (n = 4) and hyperintensity (n = 2) on the QSM map. The QSM values were higher in the bilateral central GP, bilateral peripheral GP, and bilateral substantia nigra (SN) and lower in the left red nucleus (RN) compared with the healthy controls. No significant differences were observed in the right RN, bilateral thalamus and bilateral occipital regions. Low signals on SWI sequences and high QSM values with a reversed eye-of-the-tiger sign on QSM maps are important for the diagnosis of PKAN, especially in patients who do not show the eye-of-the-tiger sign in early stages. The eye-of-the-tiger sign observed on T2WI is helpful in diagnosing PKAN when the disease has already progressed to an advanced stage.