Venous pattern of polymicrogyria detected by susceptibility weighted imaging (SWI)

Abstract

We report a case of a 9-year-old boy presenting with spastic-dystonic movement disorder of the right arm. MRI showed vast unilateral left-sided polymicrogyria (PMG) with perisylvian, temporal, frontal, and parietal location. Corresponding to the distinctly reduced gyration, the focal pattern of cortical veins in susceptibility weighted imaging (SWI) was absent due to missing sulcal depth. In contrast, adjacent regions with sufficient sulcal depth revealed a pattern with numerically increased and finer cortical veins. Therefore, with its atypical venous pattern SWI indicates an abnormal parenchymal anatomy and might be an additional helpful tool for diagnosing PMG.

Keywords: Susceptibility weighted imaging (SWI); cortical malformation; cortical veins; magnetic resonance imaging (MRI); polymicrogyria (PMG).

Fig. 1.

Different pathological patterns of cortical veins in areas with PMG. PMG is seen in the left hemisphere in (a, c, e) (T2W images). The left temporal lobe reveals PMG and a complete absent pattern of cortical veins in SWI (arrows in (a, b)), while the cortical veins in the healthy right hemisphere appear regular. The affected perisylvian location (arrows in (c)) shows a pattern of finer and numerical increased cortical veins (arrows in (d)) compared to the regular right side (arrowheads in (d)). An asymmetrical distribution of cortical veins can be seen in PMG regions with different sulcal depths: The fronto-parietal areas reveal general PMG (arrows and arrowheads in (e)) with rarefication of the cortical venous pattern in SWI in areas with extensively less gyration (arrows in (e, f)), but concentration and slight increase of the cortical venous pattern in SWI in areas with deeper sulci (arrowheads in (e, f)).