MR jet velocity mapping accurately measured peak jet velocities, agreeing well with Doppler ultrasound (standard deviation = 0.2 m/sec) in patients with valve and great vessel stenosis.
Observational (n=36)
Does MR imaging with a reduced echo time of 3.6 msec accurately measure poststenotic jet velocities compared to Doppler ultrasound in patients with valve and great vessel stenosis?
Velocity mapping with fast-echo MR imaging is an accurate noninvasive method for evaluating stenoses, particularly at sites inaccessible to ultrasound.
For measurement of poststenotic jet velocities with magnetic resonance (MR) imaging, the authors reduced the echo time (TE) of the field even-echo rephasing (FEER) velocity mapping sequence from 14.0 to 3.6 msec, so minimizing the problem of MR signal loss from turbulent fluid. In vitro use of rotating disk and stenotic flow phantoms confirmed that the 3.6-msec TE sequence enables accurate measurement of jet velocities of up to 6.0 m/sec (r = .996). Peak jet velocity measurements were made with MR imaging in 36 patients with stenosis of native heart valves (n = 9), conduits (n = 19), or Fontan connections (n = 2) or with aortic coarctation (n = 6). Peak velocity measurements made with MR imaging agreed well with measurements made with Doppler ultrasound (US), which were available in 18 cases (standard deviation = 0.2 m/sec). Velocity mapping with fast-echo MR imaging is likely to have considerable importance as a noninvasive means of locating and evaluating stenoses, particularly at sites inaccessible to US, but care must be taken to prevent errors caused by malalignment, signal loss, phase wrap, or partial-volume effects.
Kilner et al. (Tue,) conducted a observational in Stenosis of native heart valves, conduits, Fontan connections, or aortic coarctation (n=36). MR jet velocity mapping (3.6-msec TE sequence) vs. Doppler ultrasound was evaluated on Peak jet velocity measurements. MR jet velocity mapping accurately measured peak jet velocities, agreeing well with Doppler ultrasound (standard deviation = 0.2 m/sec) in patients with valve and great vessel stenosis.