title: Calculating the tumor volume of acoustic neuromas: comparison of ABC/2 formula with planimetry method.
abstract: OBJECTIVE
  The ABC/2 equation is commonly applied to measure the volume of intracranial hematoma. However, the precision of ABC/2 equation in estimating the tumor volume of acoustic neuromas is less addressed. The study is to evaluate the accuracy of the ABC/2 formula by comparing with planimetry method for estimating the tumor volumes.
  
  
  METHODS
  Thirty-two patients diagnosed with acoustic neuroma received contrast-enhanced magnetic resonance imaging of brain were recruited. The volume was calculated by the ABC/2 equation and planimetry method (defined as exact volume) at the same time. The 32 patients were divided into three groups by tumor volume to avoid volume-dependent overestimation (<3 ml, 3-6 ml and >6 ml).
  
  
  RESULTS
  The tumor volume by ABC/2 method was highly correlated to that calculated by planimetry method using linear regression analysis (R2=0.985). Pearson correlation coefficient (r=0.993, p<0.001) demonstrates nearly perfect association between two methods.
  
  
  CONCLUSIONS
  The ABC/2 formula is an easy method in estimating the tumor volume of acoustic neuromas that is not inferior to planimetry method.
authors: Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors: Yi-Lin
authors: YL
authors: Yu
authors: Meei-Shyuan
authors: MS
authors: Lee
authors: Chun-Jung
authors: CJ
authors: Juan
authors: Dueng-Yuan
authors: DY
authors: Hueng
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003390:Cranial Nerve Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology*; D012044:Regression Analysis; D012737:Sex Factors; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
keywords: ABC; Acoustic neuromas; Exact volume; IAC; MRI; Planimetry; Tumor volume; Vestibular schwannomas; internal auditory canal; magnetic resonance imaging