Comparison of outcomes with/without preoperative embolization for meningiomas with diluted N-butyl-2-cyanoacrylate.

BACKGROUND: Preoperative embolization for meningiomas is controversial regarding its effectiveness in reducing intraoperative blood loss and operative time. In contrast, some reports have documented improved surgical outcomes in large meningiomas. In this study, we retrospectively compared the outcomes of craniotomy for meningiomas with/without preoperative embolization with diluted N-butyl-2-cyanoacrylate (NBCA) primarily in a single institution. METHODS: Data (World Health Organization grade, Simpson grade, maximum tumor diameter, intraoperative bleeding, operative time, history of hypertension, and time from embolization to craniotomy) of patients with initial intracranial meningiomas were compared with or without preoperative embolization from January 2015 to April 2022. RESULTS: The embolization group consisted of 56 patients and the nonembolization group included 76 patients. Diluted NBCA (13% concentration for all patients) was used in 51 of 56 patients (91.1%) who underwent transarterial embolization. Permanent neurological complications occurred in 2 (3.6%) patients. Intraoperative bleeding was significantly lower in the embolization group for a maximum tumor diameter ≥40 mm (155 vs. 305 ml, respectively, p < 0.01). In the nonembolization group, for a maximum tumor diameter ≥30 mm, patients with hypertension had more intraoperative bleeding than non-hypertensive ones. CONCLUSIONS: Despite its limitations, the present results showed that, under certain conditions, preoperative embolization for intracranial meningiomas caused less intraoperative bleeding. The safety of treatment was comparable with that reported in the Japan Registry of NeuroEndovascular Therapy 3 (JR-NET3) with a complication rate of 3.7% for preoperative embolization of meningiomas, despite the treatment focused on the liquid embolization material.

Infiltrated Embolization of Meningioma with Dilute Cyanoacrylate Glue.

We describe the efficacy and technical aspects of infiltrated preoperative embolization of meningioma by penetration of very dilute glue. In this method, a 13% n-butyl-cyanoacrylate (NBCA)-lipiodol mixture is injected extremely slowly from the middle meningeal artery (MMA) in a similar manner to plug and push injection of ethylene vinyl alcohol copolymer mixed with tantalum and dimethyl sulfoxide (Onyx®) after the tortuous side feeders are proximally embolized. The glue is infiltrated into small tumor arteries and extends to inaccessible feeders from deep meningeal arteries. Since 2011, we have used this technique in the embolization of 32 cases preoperatively diagnosed with meningioma. Intratumoral embolization was possible in 30 cases (94%), and a greater than 50% reduction in contrast area of contrast-enhanced T1-weighted MR imaging (T1-WI) was achieved in 18 cases (56%). Two cases achieved complete devascularization, showing a remarkable shrinkage in tumor size after embolization. If excessive reflux of embolization and the resulting migration of glue into normal arteries is achieved, this method provides extremely effective devascularization on surgical extirpation. It might also be applicable to surgically untreatable meningiomas as a semi-radical treatment option.

Computed tomography imaging of transferrin targeting liposomes encapsulating both boron and iodine contrast agents by convection-enhanced delivery to F98 rat glioma for boron neutron capture therapy.

BACKGROUND: To achieve potent tumor-selective antitumor efficacy by boron neutron capture therapy (BNCT), it is important to have a significant differential uptake of 10B between tumor cells and normal cells. This should enable BNCT to reduce damage to normal tissues compared with other radiation therapies. OBJECTIVE: To augment the therapeutic efficacy of BNCT, we used transferrin-conjugated polyethylene glycol (PEG) (TF-PEG) liposome encapsulating sodium borocaptate and Iomeprol, an iodine contrast agent, with intratumoral convection-enhanced delivery (CED) in a rat glioma tumor model. METHODS: The in vitro (10)B concentration of F98 rat glioma cells was determined by inductively coupled plasma atomic emission spectrometry after incubation with either TF-PEG or PEG liposomes. For in vivo biodistribution studies, (10)B concentrations within blood, normal brain tissue, and intracerebrally transplanted F98 cells were measured with inductively coupled plasma-atomic emission spectrometry after CED of the compounds, and computed tomography was performed at selected time intervals. RESULTS: (10)B concentrations of F98 cultured glioma cells in vitro 6 hours after exposure to PEG and TF-PEG liposome were 16.1 and 51.9 ng (10)B/10(6) cells, respectively. (10)B concentrations in F98 glioma tissue 24 hours after CED were 22.5 and 82.2 µg/g, by PEG and TF-PEG liposome, respectively, with lower (10)B concentrations in blood and normal brain. Iomeprol provided vivid and stable enhanced computed tomography imaging of the transplanted tumor even 72 hours after CED by TF-PEG liposome. Conversely, tissue enhancement had already washed out at 24 hours after CED of the PEG liposomes. CONCLUSION: The combination of TF-PEG liposome encapsulating sodium borocaptate and Iomeprol and intratumoral CED enables not only a precise and potent targeting of boron delivery to the tumor tissue, but also the ability to follow the trace of boron delivery administered intratumorally by real-time computed tomography.