In 34 patients with
intracranial meningiomas, CT, MR, 1H MR spectroscopy, MR volumetric measurements, intraoperative ultrasound, and histopathologic findings were used to compare the efficacy of two embolization techniques: 1) administration of 150- to 300-microns PVA particles in the usual
suspension, and 2) administration of 50- to 150-microns PVA particles in a highly diluted
suspension.
RESULTS: Angiography after embolization demonstrated the total elimination of
tumor blush in all patients. Contrast-enhanced MR after the administration of 150- to 300-microns PVA particles revealed a reduction of
tumor enhancement in only two out of 14 patients. Only after the use of small particles could significant
tumor necrosis be depicted on MR and confirmed histopathologically after surgery. In 12 of 20 patients, 30% to 95% of the whole
tumor was necrotic with 17% to 20% reduction of
tumor volume in four cases, leading to recovery from the initial
neurologic deficits. In three of 20 patients without sufficient
steroid medication before the treatment,
tumor swelling occurred. Postembolization MR disclosed a
tumor volume increase of 10% to 20% in these patients. 1H MR spectroscopy of the
tumors showed an increase of
lactate and aliphatic
lipid compounds after embolization, indicating
tumor infarction. Surgical removal of effectively embolized
meningiomas without significant blood loss was possible. The appearance of the
tumor at operation, ultrasound examination, and the histopathologic examination of different parts of the
tumor confirmed the preoperative MR findings suggesting
necrosis.
CONCLUSION: Extended microembolization with 50- to 150-microns PVA particles improves the surgical treatment of
meningiomas, as compared with larger particle embolization. It may also be the only treatment required in older or high-risk patients. The protective effect of
steroid medication before the endovascular treatment of
meningiomas is suggested by our study.