title: Real-time flow with fast GPU reconstruction for continuous assessment of cardiac output.
abstract: OBJECTIVE
  To demonstrate the feasibility of real-time phase contrast magnetic resonance (PCMR) assessment of continuous cardiac output with a heterogeneous (CPU/GPU) system for online image reconstruction.
  
  
  METHODS
  Twenty healthy volunteers underwent aortic flow examination during exercise using a real-time spiral PCMR sequence. Acquired data were reconstructed in online fashion using an iterative sensitivity encoding (SENSE) algorithm implemented on an external computer equipped with a GPU card. Importantly, data were sent back to the scanner console for viewing. A multithreaded CPU implementation of the real-time PCMR reconstruction was used as a reference point for the online GPU reconstruction assessment and validation. A semiautomated segmentation and registration algorithm was applied for flow data analysis.
  
  
  RESULTS
  There was good agreement between the GPU and CPU reconstruction (-0.4 ± 0.8 mL). There was a significant speed-up compared to the CPU reconstruction (15×). This translated into the flow data being available on the scanner console ≈9 seconds after acquisition finished. This compares to an estimated time using the CPU implementation of 83 minutes.
  
  
  CONCLUSIONS
  Our heterogeneous image reconstruction system provides a base for translation of complex MRI algorithms into clinical workflow. We demonstrated its feasibility using real-time PCMR assessment of continuous cardiac output as an example.
authors: UCL Institute of Cardiovascular Science, Centre for Cardiovascular Imaging, London, United Kingdom.
authors: Grzegorz Tomasz
authors: GT
authors: Kowalik
authors: Jennifer Anne
authors: JA
authors: Steeden
authors: Bejal
authors: B
authors: Pandya
authors: Freddy
authors: F
authors: Odille
authors: David
authors: D
authors: Atkinson
authors: Andrew
authors: A
authors: Taylor
authors: Vivek
authors: V
authors: Muthurangu
mesh_terms: D000328:Adult; D000465:Algorithms; D001011:Aorta / Q000033:anatomy & histology / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D003196:Computer Graphics / Q000295:instrumentation*; D003199:Computer Systems; D004867:Equipment Design; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation