title: Modeling the pattern of contrast extravasation in acute intracerebral hemorrhage using dynamic contrast-enhanced MR.
abstract: BACKGROUND
  Contrast extravasation (CE) in spontaneous intracerebral hemorrhage (ICH), coined the spot sign, predicts hematoma expansion (HE) and poor clinical outcome. The dynamic relationship between CE and the mode of ICH growth are poorly understood. We characterized the in vivo pattern and rate of HE using a novel animal model of acute ICH.
  
  
  METHODS
  Basal ganglia ICH was created in 14 Yorkshire swine utilizing a novel MRI integrated model, permitting real-time CE observation using dynamic contrast-enhanced (DCE) MRI. Computerized planimetry measured CE volume at each time point. Spatial vector analysis along three orthogonal axes determined distance vectors. Maximizing and minimizing the coefficient of determination defined the temporal phases of growth and stability, respectively. CE rate was calculated using a Patlak model.
  
  
  RESULTS
  Asymmetric growth and variable rates of expansion characterized HE defining three distinct growth phases and patterns. A primary growth phase (duration 160 s; IQR 50-130) demonstrated rapid linear growth (0.04 mm/s IQR 0.01-0.10) accounting for 85 ± 15 % of total HE. The stationary phase demonstrated stability (duration 145 s; IQR 0-655). A secondary growth phase (duration 300; 130-600 s) accounted for 23 ± 8 % of total HE. In the primary and secondary growth phase, asymmetric growth occurred in the anterior-posterior (AP) planes (0.056 mm/s; p = 0.026 and 0.0112 mm/s; p = 0.03). Monophasic 2 (14 %), biphasic 4 (35 %) (primary followed by secondary growth), and triphasic 8 (56 %) patterns (primary, stationary, and secondary growth phase) were observed.
  
  
  CONCLUSIONS
  A novel model of ICH provides real-time study of the dynamics and rate of CE. This data facilitates the understanding of pattern and rate of ICH formation.
authors.affiliation: Department of Medical Imaging, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room AG-31E, Toronto, ON, M4N 3M5, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Liu
authors.forename: T J
authors.initials: TJ
authors.lastname: Huynh
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: D
authors.initials: D
authors.lastname: Ramsay
authors.forename: K
authors.initials: K
authors.lastname: Hynynen
authors.forename: R I
authors.initials: RI
authors.lastname: Aviv
mesh_terms: D000818:Animals; D002543:Cerebral Hemorrhage / Q000175:diagnosis*; D004195:Disease Models, Animal; D006406:Hematoma / Q000175:diagnosis*; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008959:Models, Neurological; D013552:Swine