Neurotoxicity of subarachnoid Gd-based contrast agent accumulation: a potential complication of intraoperative MRI?

OBJECTIVE: Intraoperative MRI with Gd-based contrast agent (GBCA) improves the extent of resection of contrast-enhancing brain tumors. Signal changes of CSF due to perioperative GBCA leakage in the subarachnoid space have been reported. However, although GBCA potentially exhibits neurotoxic effects, so far no associated complications have been described. In this case series, the authors report a single-center cohort of patients with subarachnoid GBCA extravasation after intraoperative MRI and discuss potential neurotoxic complications and potential ways of avoiding them. METHODS: All patients with CSF signal increase on unenhanced T1-weighted and FLAIR images on postoperative MRI, who had previously undergone tumor resection with use of intraoperative MRI, were retrospectively included and compared with a control cohort. The control group was matched in age, tumor characteristics, and extent of resection; comparisons were made regarding postoperative seizures and ICU stay. A subgroup with initially diagnosed malignant glioma was additionally analyzed for potential delay of initiation of adjuvant treatment and overall survival. RESULTS: Seven patients with postoperative GBCA accumulation in the subarachnoid space were identified; 5 presented with focal seizures and altered mental status postoperatively. Poor patient condition led to extended ICU stay and prolonged delay of the initiation of adjuvant treatment in patients with newly diagnosed malignant glioma. Overall survival was reduced compared to the matched control group. CONCLUSIONS: The results suggest that there might be a risk of neurotoxic complications if GBCA that is intravenously applied during neurosurgery leaks into the subarachnoid space. Patients with highly vascularized tumors with intraoperative bleeding seem to be especially at risk for GBCA accumulation and neurotoxic complications. Therefore, awareness of the potential risk of complicating GBCA leakage is mandatory in the application of intraoperative GBCA.

Microsurgical Treatment and Follow-Up of KOOS Grade IV Vestibular Schwannoma: Therapeutic Concept and Future Perspective.

PURPOSE: Surgery of KOOS IV vestibular schwannoma remains challenging regarding the balance of extent of tumor resection (EoR) and functional outcome. Our aim was to evaluate the outcome of surgical resection and define a cut-off value for safe resection with low risk for tumor regrowth of KOOS IV vestibular schwannoma. METHODS: All patients presenting at the authors' institution between 2000 and 2019 with surgically treated KOOS IV vestibular schwannoma were included. Outcome measures included EoR, facial/hearing nerve function, surgical complications and progression of residual tumor during the median follow-up period of 28 months. RESULTS: In 58 patients, mean tumor volume was 17.1 ± 9.2 cm3, and mean EoR of 81.6 ± 16.8% could be achieved. Fifty-one patients were available for the follow-up analysis. Growth of residual tumor was observed in 11 patients (21.6%) followed by adjuvant treatment with stereotactic radiosurgery or repeat surgery in 15 patients (29.4%). Overall serviceable hearing preservation was achieved in 38 patients (74.5%) and good facial outcome at discharge was observed in 66.7% of patients, significantly increasing to 82.4% at follow-up. Independent predictors for residual tumor growth was EoR ≤ 87% (OR11.1) with a higher EoR being associated with a very low number of residual tumor progression amounting to 7.1% at follow-up (p=0.008). CONCLUSIONS: Subtotal tumor resection is a good therapeutic concept in patients with KOOS IV vestibular schwannoma resulting in a high rate of good hearing and facial nerve function and a very low rate of subsequent tumor progression. The goal of surgery should be to achieve more than 87% of tumor resection to keep residual tumor progression low.

The role of magnetic resonance imaging in the diagnosis of central nervous system involvement in children with acute lymphoblastic leukemia.

PURPOSE: Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in childhood. As central nervous system (CNS) involvement requires an intensified CNS-targeted therapy, timely diagnosis is essential. The aim of this retrospective analysis was to evaluate whether cranial magnetic resonance imaging (MRI) examinations findings correlate with cerebrospinal fluid (CSF) analysis on CNS involvement and whether MRI examinations reveal incidental findings with a clinical consequence. METHODS: All pediatric patients with ALL at our institution between 1998 and 2016 were identified. Patients were divided into two groups: de novo and relapsed ALL. Both groups were analyzed separately for the presence of CNS involvement. Incidental findings were also evaluated. RESULTS: Two hundred fifteen patients with de novo ALL and 31 with relapsed ALL were identified. In the de novo group, no patient was diagnosed CNS positive based on MRI results alone. In relapsed patients, only one patient had a positive MRI with negative CSF results and no neurological symptoms, thus was classified CNS positive solely on the basis of the MRI. In both groups, no patient showed an incidental finding that required therapy. CONCLUSION: In our study, MRI examinations do not improve the detection of CNS involvement compared with CSF analysis alone. In addition, the analysis of incidental findings does not add value to the performance of an MRI examination performed prior to treatment. Overall, MRI prior to treatment in pediatric patients with ALL is not necessary.