title: Magnetic resonance imaging fluid-attenuated inversion recovery sequence signal reduction after endoscopic endonasal transcribiform total resection of olfactory groove meningiomas.
abstract: BACKGROUND
  Olfactory groove meningiomas grow insidiously and compress adjacent cerebral structures. Achieving complete removal without further damage to frontal lobes can be difficult. Microsurgical removal of large lesions is a challenging procedure and usually involves some brain retraction. The endoscopic endonasal approaches (EEAs) for tumors arising from the anterior fossa have been well described; however, their effect on the adjacent brain tissue has not. Herein, the authors utilized the magnetic resonance imaging fluid attenuated inversion recovery (FLAIR) sequence signal as a marker for edema and gliosis on pre- and post-operative images of olfactory groove meningiomas, thus presenting an objective parameter for brain injury after surgical manipulation.
  
  
  METHODS
  Imaging of 18 olfactory groove meningiomas removed through EEAs was reviewed. Tumor and pre/postoperative FLAIR signal volumes were assessed utilizing the DICOM image viewer OsiriX(®). Inclusion criteria were: (1) No previous treatment; (2) EEA gross total removal; (3) no further treatment.
  
  
  RESULTS
  There were 14 females and 4 males; the average age was 53.8 years (±8.85 years). Average tumor volume was 24.75 cm(3) (±23.26 cm(3), range 2.8-75.7 cm(3)), average preoperative FLAIR volume 31.17 cm(3) (±39.38 cm(3), range 0-127.5 cm(3)) and average postoperative change volume, 4.16 cm(3) (±6.18 cm(3), range 0-22.2 cm(3)). Average time of postoperative scanning was 6 months (range 0.14-20 months). In all cases (100%) gross total tumor removal was achieved. Nine patients (50%) had no postoperative FLAIR changes. In 2 patients (9%) there was minimal increase of changes postoperatively (2.2 cm(3) and 6 cm(3) respectively); all others demonstrated image improvement. The most common complication was postoperative cerebrospinal fluid leakage (27.8%); 1 patient (5.5%) died due to systemic complications and pulmonary sepsis.
  
  
  CONCLUSIONS
  FLAIR signal changes tend to resolve after endonasal tumor resection and do not seem to worsen with this operative technique.
authors.affiliation: Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA ; Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Prevedello
authors.affiliation: Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
authors.forename: Leo F S
authors.initials: LF
authors.lastname: Ditzel Filho
authors.affiliation: Department of Neurological Surgery, University of Pittsburgh Medical Center, UPMC Presbyterian, Pittsburgh, PA 15213, USA.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Fernandez-Miranda
authors.affiliation: Department of Neurological Sciences, Division of Neurosurgery, University of Napoli Federico II, 80131 Naples, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Solari
authors.affiliation: Department of Neurological Surgery, University of São Paulo, Central Institute of the University of São Paulo Medical School Clinical Hospital, São Paulo, Brazil.
authors.forename: Marcelo Prudente
authors.initials: MP
authors.lastname: do Espírito Santo
authors.affiliation: Department of Biomedical Informatics, Center for Biostatistics, College of Medicine, The Ohio State University, Columbus, OH 43221, USA.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Wehr
authors.affiliation: Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA ; Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Carrau
authors.affiliation: Department of Neurosurgery, Aurora Neuroscience Innovation Institute, Milwaukee, WI 53215, USA.
authors.forename: Amin B
authors.initials: AB
authors.lastname: Kassam
keywords: Anterior cranial fossa; endonasal endoscopic; fluid-attenuated inversion recovery; magnetic resonance imaging; meningioma; olfactory groove