Timing of diffusion tensor imaging in the management of a ruptured pediatric arteriovenous malformation: illustrative case.

BACKGROUND: Diffusion tensor imaging (DTI) can characterize eloquent white matter tracts affected by brain arteriovenous malformations (AVMs). However, DTI interpretation can be difficult in ruptured cases due to the presence of blood products. The authors present the case of a ruptured pediatric AVM in the corticospinal tract (CST) and discuss how DTI at different time points informed the treatment. OBSERVATIONS: A 9-year-old female presented with a sudden headache and left hemiparesis. She was found to have a Spetzler-Martin grade III, Supplementary grade I AVM in the right caudate and centrum semiovale, with obliteration and corresponding reduced fractional anisotropy (FA), fiber density (FD), and tract count (TC) of the adjacent CST on DTI. The patient remained stable and was scheduled for elective resection following a 6-week period to facilitate hematoma resorption. After 6 weeks, repeat DTI showed part of the nidus within intact CST fibers with concordant improvement in FA, FD, and TC. Considering the nidus location, CST integrity, and motor function recovery, surgery was deferred in favor of stereotactic radiosurgery. LESSONS: In ruptured AVMs, DTI may initially create an incomplete picture and false assumptions about white matter tract integrity. DTI should be repeated if delayed treatment is appropriate to ensure informed decision-making and prevent avoidable permanent neurological deficits. https://thejns.org/doi/10.3171/CASE24225.

Blood Pressure and Spot Sign in Spontaneous Supratentorial Subcortical Intracerebral Hemorrhage.

BACKGROUND: Spontaneous intracerebral hemorrhage is a potentially devastating cause of brain injury, often occurring secondary to hypertension. Contrast extravasation on computed tomography angiography (CTA), known as the spot sign, has been shown to predict hematoma expansion and worse outcomes. Although hypertension has been associated with an increased rate of the spot sign being present, the relationship between spot sign and blood pressure has not been fully explored. METHODS: We retrospectively analyzed data from 134 patients (40 women and 94 men, mean age 62.3 ± 15.73 years) presenting to a tertiary academic medical center with spontaneous supratentorial subcortical intracerebral hemorrhage from 1/1/2018 to 1/4/2021. RESULTS: A spot sign was demonstrated in images of 18 patients (13.43%) and correlated with a higher intracerebral hemorrhage score (2.61 ± 1.42 vs. 1.31 ± 1.25, p = 0.002), larger hematoma volume (53.49cm3 ± 32.08 vs. 23.45cm3 ± 25.65, p = 0.001), lower Glasgow Coma Scale on arrival (9.06 ± 4.56 vs. 11.74 ± 3.65, p = 0.027), increased risk of hematoma expansion (16.67% vs. 5.26%, p = 0.042), and need for surgical intervention (66.67% vs. 15.52%, p < 0.001). We did not see a correlation with age, sex, or underlying comorbidities. The presence of spot sign correlated with higher modified Rankin scores at discharge (4.94 ± 1.00 vs. 3.92 ± 1.64, p < 0.001). We saw significantly higher systolic blood pressure at the time of CTA in patients with a spot sign (184 mm Hg ± 43.11 vs. 153 mm Hg ± 36.99, p = 0.009) and the highest recorded blood pressure (p = 0.019), although not blood pressure on arrival (p = 0.081). Performing CTA early in the process of blood pressure lowering was associated with a spot sign (p < 0.001). CONCLUSIONS: The presence of spot sign correlates with larger hematomas, worse outcomes, and increased surgical intervention. There is a significant association between spot sign and systolic blood pressure at the time of CTA, with the highest systolic blood pressure being recorded prior to CTA. Although the role of intensive blood pressure management in spontaneous intracerebral hemorrhage remains a subject of debate, patients with a spot sign may be a subgroup that could benefit from this.

Technical notes on the placement of cerebral microdialysis: A single center experience.

Background: Cerebral microdialysis enables monitoring of brain metabolism and can be an important part of multimodal monitoring strategies in a variety of brain injuries. Microdialysis catheters can be placed in brain parenchyma through a burr hole, a cranial bolt, or directly at the time of an open craniotomy or craniectomy. The location of catheters in relation to brain pathology is important to the interpretation of data and guidance of interventions. Methods: Here we retrospectively review the use of cerebral microdialysis at a US Regional Medical Center between March 2018 and February 2022 and provide detailed descriptions and technical nuances of the different methods to place microdialysis catheters. Results: Eighty two unique microdialysis catheters were utilized in 52 patients. 35 (42.68%) were placed via a quad-lumen bolt and 47 (57.32%) were placed through craniotomies. 27 catheters (32.93%) were placed in a perilesional location, 50 (60.98%) were located in healthy tissue, and 6 (7.32%) were mispositioned. No significant difference was seen between placement by bolt or craniotomy in regard to perilesional location, mispositioning, or complications. Conclusion: With careful planning and thoughtful execution, cerebral microdialysis catheters can be successfully placed though a variety of strategies to optimize and individualize brain monitoring in different clinical settings. This paper provides a detailed guide for the various methods of catheter placement to help providers begin or expand their use of cerebral microdialysis.

Intranasal administration as a route for drug delivery to the brain: evidence for a unique pathway for albumin.

A variety of compounds will distribute into the brain when placed at the cribriform plate by intranasal (i.n.) administration. In this study, we investigated the ability of albumin, a protein that can act as a drug carrier but is excluded from brain by the blood-brain barrier, to distribute into the brain after i.n. administration. We labeled bovine serum albumin with [(125)I] ([(125)I]Alb) and studied its uptake into 11 brain regions and its entry into the blood from 5 minutes to 6 hours after i.n. administration. [(125)I]Alb was present throughout the brain at 5 minutes. Several regions showed distinct peaks in uptake that ranged from 5 minutes (parietal cortex) to 60 minutes (midbrain). About 2-4% of the i.n. [(125)I]Alb entered the bloodstream. The highest levels occurred in the olfactory bulb and striatum. Distribution was dose-dependent, with less taken up by whole brain, cortex, and blood at the higher dose of albumin. Uptake was selectively increased into the olfactory bulb and cortex by the fluid-phase stimulator PMA (phorbol 12-myristate 13-acetate), but inhibitors to receptor-mediated transcytosis, caveolae, and phosphoinositide 3-kinase were without effect. Albumin altered the distribution of radioactive leptin given by i.n. administration, decreasing uptake into the blood and by the cerebellum and increasing uptake by the hypothalamus. We conclude that [(125)I]Alb administered i.n. reaches all parts of the brain through a dose-dependent mechanism that may involve fluid-phase transcytosis and, as illustrated by leptin, can affect the delivery of other substances to the brain after their i.n. administration.