Rao, Dinesh

Objective: To compare the prevalence and patterns of transverse sinus stenosis (TSS) in patients with lateral skull base spontaneous cerebrospinal fluid (sCSF) leaks and idiopathic intracranial hypertension (IIH), to clarify its role in leak pathogenesis and implications for venous-directed therapies. Study design: Retrospective case-control study. Setting: Single tertiary care institution. Patients: Adults with lateral skull base sCSF leaks confirmed by clinical, laboratory, or surgical findings, and adults with IIH without cranial CSF leaks meeting Modified Dandy criteria. Intervention: Independent magnetic resonance venography evaluation by 2 fellowship-trained neuroradiologists. Main outcome measures: Presence, laterality, and severity of TSS. Results: Eighteen patients with sCSF leaks and 78 patients with IIH were included. The rate of individual TSS, including both unilateral and bilateral cases, was higher in the IIH cohort than in the sCSF leak cohort (bilateral TSS: n=66, 84.6% vs. n=6, 33.3%; P <0.001). Severe bilateral TSS was observed more in the IIH cohort (n=40, 51.3%) compared with the sCSF leak cohort (n=1, 5.6%; P <0.001). Conclusions: Though patients with lateral skull base sCSF leaks have TSS, the significantly lower rate compared with patients with IIH suggests that TSS may play a lesser role in the pathogenesis of lateral skull base defects. These findings indicate that the role of transverse sinus stenting in lateral skull base sCSF leaks remains uncertain and highlight the need to further investigate local remodeling processes when considering the role of venous sinus stenting in this population.

Despite their similar nomenclature, Neurofibromatosis type 1 (NF1) and “Neurofibromatosis type 2” are discrete and clinically distinguishable entities. The name of “neurofibromatosis type 2” has been changed to NF2-related schwannomatosis, to reflect the fact that neurofibromas do not occur in this syndrome and therefore the name “Neurofibromatosis” is factually incorrect. Furthermore, multiple schwannomas, a hallmark feature of NF2, can also occur in patients with mutations in genes including SMARCB1 and LZTR1, all exhibiting overlapping clinical features. Current understanding suggests that schwannomatosis (SWN) encompasses a range of clinical presentations consisting of clearly defined, separate subtypes which share a common phenotype of schwannomas. Recognizing these newly emerging subtypes, the International Consensus Group on Neurofibromatosis Diagnostic Criteria (I-NF-DC) proposed a revised nomenclature for NF2 and related disorders in 2022. This review article focuses on this critical update in diagnostic terminology, highlighting the key gene-related SWN subtypes relevant to neuroradiologists. By emphasizing molecular testing alongside clinical features, the revised system facilitates a more precise diagnosis, potentially paving the way for personalized treatment strategies. Additionally, the flexible structure accommodates future discoveries of genes associated with SWN.

Background: Severe traumatic brain injuries (TBI), commonly due to motor vehicle accidents may cause death and long-term disability especially when the acceleration-deceleration force on the brain is massive. This may cause shearing of the axonal connections within the cerebral cortex and brainstem in a process referred to as diffuse axonal injury (DAI). Extensive DAI has been postulated to be a poor prognostic indicator for neurological recovery. In our institution, several patients with Grade 3 DAI were observed to recover and achieve neurological outcomes greater than expected given the presence of brainstem injury. Methods: MRI studies from 100 patients admitted to a large tertiary trauma center for TBI were retrospectively analyzed by two fellowship-trained neuroradiologists. The size of DAI lesions, location of injury within the brainstem, and the number of discrete DAI lesions were measured and recorded. Glasgow Coma Scale (GCS) on arrival and at discharge was noted, as well as the presence of other neurological injuries. Results: Of 20 patients initially noted to have DAI with lesions of the brainstem, eight of them were discharged with Glasgow Coma Scale (GCS) of 14–15. The 12 patients discharged with reduced consciousness (average GC 7.1) demonstrated a greater number of larger lesions, with a predilection for the dorsal pons. Conclusion: These results suggest that large, numerous pontine lesions may indicate worse neurological outcomes in patients with these findings.