sairamgeethanath
commented
4 years ago seq.report thinks it is 3D because of this line: seq.add_block(gz_reph, gx_pre, gy_pre) but the same line in write_gre.py does not seem to break it! It is not necessary that the presence of 3 gradients along different directions need to be a 3D sequence
Describe the bug seq.report() is unable to detect a Cartesian trajectory for a spin echo implementation
To Reproduce
Share the pulse sequence code, if possible. for i in range(Ny):
gy_pre = make_trapezoid(channel='y', area=phase_areas[i], duration=t_pe, system=system)
Excitation blocks
seq.add_block(rf_ex, gz_ex) seq.add_block(gz_reph, gx_pre, gy_pre)
seq.add_block(delay_TE1)
Refocusing and phase encoding
seq.add_block(rf_ref, gz_ref)
Delay and readout
seq.add_block(delay_TE2)
seq.add_block(gx,adc)
report = seq.report() print(report)
Expected behavior Needs to show that it is 2D Cartesian with spatial resolutions only in x and y
Screenshots Output from report API - wth delay commented Number of blocks: 512 Number of events: RF: 256 Gx: 256 Gy: 128 Gz: 384 ADC: 128 Delay: 0 Sequence duration: 1.840640 s TE: 0.009571 s TR: 0.014380 s Flip angle: 90.00 180.00 deg Unique k-space positions (aka cols, rows, etc.): 128 128 1 Dimensions: 3 Spatial resolution: 1.95 mm Spatial resolution: 1.95 mm Spatial resolution: 31.25 mm Repetitions/slices/contrasts: 1.0 Cartesian encoding trajectory detected Block timing check passed successfully Max gradient: 107246 103226 666667 Hz/m == 2.52 2.42 15.66 mT/m Max slew rate: 5362275148 5333333333 5333333333 Hz/m/s == 125.95 125.27 125.27 mT/m/s Max absolute gradient: 666667 Hz/m == 15.66 mT/m Max absolute slew rate: 7.90635e+09 Hz/m/s == 185.70 T/m/s
Desktop (please complete the following information):
Additional context If I uncomment the delays, the report cannot evaluate block timings; Block timing check failed. Error listing follows: