title: Assessment of pituitary adenoma volumetric change using longitudinal MR image registration.
abstract: BACKGROUND
  Change detection is a crucial factor in monitoring of slowly evolving pathologies. The objective of the study was to test a semi-automatic method applied on longitudinal MRI monitoring of volume change in pituitary macroadenomas.
  
  
  METHODS
  The proposed method is based on a visual comparison of geometrically corrected, co-registered, intensity-normalized contrast-enhanced (CE) 3D GRE T1-weighted images. Qualitative volume changes based on this applied method were compared with experts' readings of conventional pre- and post-CE 2D T1-weighted images. Magnetic resonance (MR) imaging was performed two to four times in 13 patients with a total combination of 29 time points.
  
  
  RESULTS
  Compared to conventional 2D MR readings, a diagnosis of tumor growth (yes/no) was changed in 5 of 13 patients (38%) at 9 of the 29 combinations of time points (31%) using the 3D-based semi-automatic method. With manual tumor tracings as reference, McNemar's test showed a significant difference between the two methods.
  
  
  CONCLUSIONS
  Visual comparison of geometrically corrected, intensity-normalized, and affine-aligned longitudinal 3D images may enable more accurate assessment of qualitative volumetric change in pituitary adenomas than conventional reading of 2D images.
authors.affiliation: Clinic for Imaging and Intervention, Oslo University Hospital-Rikshospitalet, Sognsvannsvn 20, Oslo, Norway. geir.ringstad@rikshospitalet.no
authors.forename: Geir Andre
authors.initials: GA
authors.lastname: Ringstad
authors.forename: Kyrre Eeg
authors.initials: KE
authors.lastname: Emblem
authors.forename: Dominic
authors.initials: D
authors.lastname: Holland
authors.forename: Anders M
authors.initials: AM
authors.lastname: Dale
authors.forename: Atle
authors.initials: A
authors.lastname: Bjornerud
authors.forename: John K
authors.initials: JK
authors.lastname: Hald
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000473:pathology*; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media