Purpose or Case Report: Accurate imaging characterization of chronic subdural hemorrhage (cSDH) has clinical and forensic implications, and continues to challenge the radiologist. The MRI characteristics of surgically proven cSDH were retrospectively reviewed in the context of known pathomorphology of the aging SDH.
Methods & Materials: A search of the pediatric neurosurgical database at a large children's hospital was performed with the terms “chronic subdural hemorrhage” and “subdural drainage”. Data was available from 2010-2017. Chart review was performed. Operative findings, pertinent demographic and clinical information was recorded. Preoperative MR imaging of 14 patients with surgically confirmed cSDH was retrospectively reviewed. NECT was reviewed if available. Imaging was surveyed by a senior pediatric neuroradiologist and a senior radiology resident. This retrospective study is pending approval by the Institutional Review Board.
Results: 14 patients with 19 drained subdural compartments were identified. The majority of MR imaging was performed within 3 days antecedent to drainage (84%). Most cases were determined to be sequelae of non-accidental trauma (74%). Using gray matter as an internal control, the fluid signal characteristics were recorded (table 1). All cases showed internal membranes (figure 1). The majority of the membranes demonstrated post contrast enhancement and a minority of cases showed enhancement of the meningeal dura (table 2). A subjective determination was made as to which axial sequence showed the membranes most conspicuously. Membranes were determined to be most conspicuous on SWI (61%) or T2 (39%) in all cases. All sequences and planes were then evaluated to determine which best demonstrated membranes. Coronal T2 (31%), axial T2 (31%), and axial SWI (37%) were nearly equal.
Conclusions: Our data of the signal characteristics of cSDH shares some similarities with current literature. We chronicle the paradoxical signal features of T2* and SWI as well as the confounding variability of T1, T2, and FLAIR imaging. However, analysis of fluid characteristics alone provides an incomplete evaluation of cSDH. Importantly, in our cohort, all patients demonstrated internal membranes within the cSDH and assessment of these structures is critical. Our results showed the most useful sequences for detection of membranes to be T2 and SWI, particularly when obtained in orthogonal planes. The administration of intravenous contrast was of limited utility in the evaluation of cSDH.