Postembolization Change in Magnetic Resonance Imaging Contrast Enhancement of Meningiomas Is a Better Predictor of Intraoperative Blood Loss Than Angiography

Longitudinal Imaging of Tumor Perfusion After Preoperative Endovascular Embolization in Meningiomas: Surgical Time Window Selecting, Clinical Consideration, and Outcomes

OBJECTIVE

To quantitatively investigate the longitudinal computed tomography perfusion (CTP) imaging in meningiomas preoperatively embolized using microcatheters.

METHODS

This retrospective monocentric study included 27 patients with symptomatic supratentorial meningiomas. Quantitative computed tomography perfusion (CTP) images before and postembolization were evaluated and correlated with angiographic, immunohistochemical, and clinical data.

RESULTS

The mean age of the patients was 45 ± 18 years, with a female-to-male ratio of 1.45:1. After embolization, both the embolized (Eb) and unembolized (UEb) regions showed hypoperfusion. A steady state was achieved on days 4-6 postembolization, during which differences in regional cerebral blood volume (rCBV) (Eb 0.5 ± 0.3 ml/100 mg, UEb 3.3 ± 1.4 ml/100 mg; P < 0.05), and mean transit time (MTT) (Eb 3.5 ± 1.8 s, UEb 3.1 ± 0.4 s) were observed. The cerebral blood flow (rCBF) and time to the peak (TTP) exhibited opposite patterns between Eb and UEb. A steady state was reached in rCBF (Eb 1.7 ± 1.2 ml/100 g/min, UEb 30 ± 5.4 ml/100 g/min; P < 0.01), and TTP (Eb 5 ± 4.8 s, UEb 1.8 ± 1.5 s; P < 0.01) within 4 to 6 days. Estimated blood loss (EBL) showed significant association with the surgical time interval among the 3 groups (P < 0.05). Tissue necrosis predominated over 7 days postembolization, indicating a correlation with the devascularization process. The overall incidence of postembolized headache, seizures, extremity weakness/paralysis, and postoperational headache was 11.1%, 7.4%, 3.7%; and 7.4%, respectively. All symptoms resolved by the last follow-up (3 months).

CONCLUSION

Preoperative embolization of meningiomas using N-butyl cyanoacrylate effectively induced significant and sustained tissue transformation and decreased estimated blood loss (EBL) over 7 days. Hemodynamic fluctuations tended to stabilize within 4 to 6 days.

Endovascular Embolization of Intracranial Meningiomas

Although benign in histology, the hypervascularity and skull base location of meningiomas can make them surgically challenging lesions. Preoperative endovascular embolization with superselective microcatheterization of vascular pedicles may be efficacious in decreasing intraoperative transfusion requirements with equivocal postoperative functional benefit. The potential benefits of preoperative embolization should be weighed against the risks of ischemic complications. Appropriate patient selection is critical. All patients should be monitored closely postembolization, and a course of steroids can be considered to minimize neurologic symptoms.

Clinicopathologic Factors Associated with Tumor Necrosis after Preoperative Embolization of Meningiomas

Objective

Preoperative embolization of meningiomas induces necrosis prior to surgery and facilitates resection. Lack of contrast enhancement on postembolization MRI correlates with pathological findings of necrosis and can be used to assess embolization efficacy. This study aimed to examine clinicopathologic factors associated with tumor necrosis after embolization.

Methods

A total of 119 patients with intracranial meningioma who underwent 145 surgical resections between 2010 and 2019 at our institute were reviewed. Inclusion criteria for the study were preoperative embolization with trisacryl gelatin microspheres (Embosphere) or absorbable gelatine sponge (Gelfoam). Postembolization Gd-enhanced T1-weighted and angiographic imaging, and histopathologic examination results were reviewed to evaluate the effectiveness of embolization.

Results

In all, 66 patients satisfied the inclusion criteria. In total, 36 patients were embolized with Embosphere and 30 patients were embolized with Gelfoam. Patients embolized with Embosphere had a significantly higher necrosis rate (NR) than patients with Gelfoam (21% vs. 7.1%, P <0.01). The 36 Embosphere patients were analyzed regarding clinicopathologic factors associated with NR. Tumors in 12 patients were located in the parasagittal/falx region; these patients had a significantly lower NR compared with tumors in other locations (10.6% vs. 26.2%, P = 0.016). In all, 13 patients had feeders arising from only the middle meningeal artery (MMA), which was associated with a significantly higher NR (29.3% vs. 14.4%, P = 0.015). In total, 11 patients had meningeal feeders arising from internal carotid artery (ICA), which was associated with a significantly lower NR (9.0% vs. 26.3%, P <0.01).

Conclusion

This study showed embolization agent, tumor location, and blood supply were important factors predicting necrosis after preoperative embolization.