title: Use of preoperative magnetic resonance imaging T1 and T2 sequences to determine intraoperative meningioma consistency.
abstract: BACKGROUND
  Meningioma firmness is a critical factor that influences ease of resection and risk, notably when operating on tumors intimate with neurovascular structures such as the mesial sphenoid wing. This study develops a predictive tool using preoperative magnetic resonance imaging (MRI) characteristics to determine meningioma consistency.
  
  
  METHODS
  101 patients with intracranial meningioma (50 soft/51 firm) were included. MRI characteristics of 38 tumors (19 soft/19 firm) were retrospectively reviewed to identify preoperative imaging features that were then correlated with intraoperative description of the tumor as either "soft and/or suckable" or "firm and/or fibrous". Criteria were developed to predict consistency and then blindly applied to the remaining 63 meningiomas (31 soft/32 firm).
  
  
  RESULTS
  The overall sensitivities for detecting soft and firm consistency were 90% and 56%, respectively (95% CI = 73-97% and 38-73%; P < 0.001). Compared to gray matter, meningiomas that were T2 hypointense were almost always firm. Soft meningiomas were hyperintense on T2 and hypointense on T1. Soft meningiomas were slightly larger and less likely to be associated with edema. There was a slight preponderance of firm meningiomas in the infratentorial compartment. Grade of meningioma was not predictive. Contrast enhancement, diffusion restriction, changes in overlying bone, intratumoral cysts, and angiographic features were not predictable.
  
  
  CONCLUSIONS
  This tool using T1 and T2 series predicts meningioma consistency. Such knowledge should assist the surgeon in preoperative planning and counseling.
authors: Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors: Jason M
authors: JM
authors: Hoover
authors: Jonathan M
authors: JM
authors: Morris
authors: Fredric B
authors: FB
authors: Meyer