OP12.06: Infratentorial subpial hemorrhage: an underestimated location of fetal intracranial hemorrhage

Subpial hemorrhage (SPH) is a rare type and of intracranial hemorrhage (ICH), typically seen in the neonatal populations. It differs from subarachnoid or subdural hemorrhages in both its anatomical location and underlining pathophysiology. Our aim was to describe the important and distinct neuroimaging features of SPH over the cerebellar hemispheres and vermis on fetal MRI, postmortem MRI, and neuropathology. A retrospective study from a single-centre study at the Medical University of Vienna, Austria. Out of the 100 cases (ranging from 19+0 to 37+6 weeks of gestation) 17 where had ICH on MRI. Ten case (20+5 to 32 +0), 5 female and 5 male showed infratentorial SPH. Fetal brain assessment was done via T2-weighted single-shot fast spin-echo (ssFSE) in three orthogonal planes and T1-weighted, diffusion-weighted imaging (DWI) and echo-planar imaging (EPI) in all patients. All ten fetuses had infratentorial involvement of SPH. 60% had isolated infratentorial SPH, while 40% showed infratentorial and periventricular bleed at the germinal eminence. One case, male at 24 +3 GW showed bilateral cerebellar and vermin SPH with postnatal whole exome sequencing with COL4A1 gene mutation, brain autopsy and histological confirmation that this type of hemorrhage is distinct from subarachnoid hemorrhage. Likewise all ten fetuses showed placental damage appearance with MRI, thus suggesting fetal growth restriction (FGR) according to the Delphi consensus. Therefore, among other manifestations, SPH may be a consequence of vascular placental insufficiency. SPH is a rare and poorly understood type of ICH with distinct neuroimaging morphological patterns, different from other types of ICH with histological confirmation supporting our notions that SPH is distinct from subarachnoid hemorrhage since the fetal prognosis is different. We hope our findings and descriptions will improve both awareness and recognition of this rare disorder and alert the relevant clinicians to search for a probable underlying genetic mutations.