propeller acquisition on the philips achieva recent results collected in hamburg – jan 2006
TRANSCRIPT
PROPELLER Acquisition on the Philips Achieva
Recent results collected in Hamburg – JAN 2006
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 2
Recent TSE results collected in Hamburg – JAN 2006
• Liquid-filled resolution phantom experiencing high-speed in-plane rotational motion induced by a computer controlled stepper motor
• TSE, readout matrix size = 384, 25 blades over 180°, blade width=24
STATIC MOTIONUNCORRECTED
MOTIONCORRECTED
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 3
• The plot is periodic like the actual phantom motion• Detected angles are large leading to large missing “wedges” in k-space
• TSE, readout matrix size = 384, 25 blades over 180°, blade width = 24
Detected Angular Motion k-space after motion correction
Recent TSE results collected in Hamburg – JAN 2006
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 4
• Simple short TR gradient echo acquisition – not known to Simple short TR gradient echo acquisition – not known to be published nor presented to datebe published nor presented to date
• FFEFFE, readout matrix size=256, 34 blades over 360, readout matrix size=256, 34 blades over 360°°, , blade width=24, blade acquisition duration ~=150 msecblade width=24, blade acquisition duration ~=150 msec
STATICMOTION
UNCORRECTEDMOTION
CORRECTED
Recent FFE results collected in Hamburg – JAN 2006
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 5
• Amplitude and speed of motion phantom is smaller than in TSE experiment• Because of increased number of propeller blades collected over 360°, no wedges of k-space are
missing even after correction for rotation • FFE, readout matrix size=256, 34 blades over 360°, blade width=24, blade acquisition duration
~= 150 msec
Recent FFE results collected in Hamburg – JAN 2006
Detected Angular Motion k-space after motion correction
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 6
• Animation loops showing the low resolution “disk images” Animation loops showing the low resolution “disk images” collected by every FFE propeller bladecollected by every FFE propeller blade
• Rotation is noticeable in uncorrected disk images… Rotation is noticeable in uncorrected disk images… corrected disk images are stablecorrected disk images are stable
STATICMOTION
UNCORRECTEDMOTION
CORRECTED
Recent FFE results collected in Hamburg – JAN 2006
Philips Medical Systems, E. Brian Welch, Hamburg Results JAN 2006 7
• Center of Mass criterion is not useful on FFE data• TSE center of mass is smoothly sinusoidal (LEFT GRAPH)• FFE susceptibility inconsistencies as readout direction changes with blade
orientation create a distorted center of mass trajectory (RIGHT GRAPH)
Recent TSE + FFE results collected in Hamburg – JAN 2006
STATIC TSE STATIC FFE