Magnetic resonance velocity imaging using a fast spiral phase contrast sequence

1994 ◽  
Vol 32 (4) ◽  
pp. 476-483 ◽  
Author(s):  
G. Bruce Pike ◽  
Craig H. Meyer ◽  
Thomas J. Brosnan ◽  
Norbert J. Pelc
Keyword(s):  
Magnetic Resonance ◽  
Phase Contrast ◽  
Velocity Imaging ◽  
Spiral Phase ◽  
Phase Contrast Sequence

Robust three-dimensional phase unwrapping algorithm for phase contrast magnetic resonance velocity imaging

Fringe 2005 ◽  
2006 ◽  
pp. 74-81
Author(s):  
Jonathan M. Huntley ◽  
María F. Salfity ◽  
Pablo D. Ruiz ◽  
Martin J. Graves ◽  
Rhodri Cusack ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Phase Contrast ◽  
Three Dimensional ◽  
Phase Unwrapping ◽  
Phase Contrast Magnetic Resonance ◽  
Velocity Imaging ◽  
Contrast Magnetic Resonance

scholarly journals Nonsubtractive spiral phase contrast velocity imaging

1999 ◽  
Vol 42 (4) ◽  
pp. 704-713 ◽  
Author(s):  
Lai-Chee Man ◽  
John M. Pauly ◽  
Dwight G. Nishimura ◽  
Albert Macovski
Keyword(s):  
Phase Contrast ◽  
Velocity Imaging ◽  
Spiral Phase

scholarly journals Extending the dynamic range of phase contrast magnetic resonance velocity imaging using advanced higher-dimensional phase unwrapping algorithms

2005 ◽  
Vol 3 (8) ◽  
pp. 415-427 ◽  
Author(s):  
M.F Salfity ◽  
J.M Huntley ◽  
M.J Graves ◽  
O Marklund ◽  
R Cusack ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Phase Contrast ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Phase Unwrapping ◽  
Signal To Noise ◽  
Phase Contrast Magnetic Resonance ◽  
Velocity Imaging ◽  
Contrast Magnetic Resonance

Phase contrast magnetic resonance velocity imaging is a powerful technique for quantitative in vivo blood flow measurement. Current practice normally involves restricting the sensitivity of the technique so as to avoid the problem of the measured phase being ‘wrapped’ onto the range − π to + π . However, as a result, dynamic range and signal-to-noise ratio are sacrificed. Alternatively, the true phase values can be estimated by a phase unwrapping process which consists of adding integral multiples of 2 π to the measured wrapped phase values. In the presence of noise and data undersampling, the phase unwrapping problem becomes non-trivial. In this paper, we investigate the performance of three different phase unwrapping algorithms when applied to three-dimensional (two spatial axes and one time axis) phase contrast datasets. A simple one-dimensional temporal unwrapping algorithm, a more complex and robust three-dimensional unwrapping algorithm and a novel velocity encoding unwrapping algorithm which involves unwrapping along a fourth dimension (the ‘velocity encoding’ direction) are discussed, and results from the three are presented and compared. It is shown that compared to the traditional approach, both dynamic range and signal-to-noise ratio can be increased by a factor of up to five times, which demonstrates considerable promise for a possible eventual clinical implementation. The results are also of direct relevance to users of any other technique delivering time-varying two-dimensional phase images, such as dynamic speckle interferometry and synthetic aperture radar.

scholarly journals Assessment of Cerebrospinal Fluid Hydrodynamics Using Magnetic Resonance Imaging in Postcraniospinal Surgery Patients

2021 ◽  
Author(s):  
Pankaj Arora ◽  
Kanica Rawat ◽  
Rajiv Azad ◽  
Kehkashan Chouhan
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cerebrospinal Fluid ◽  
Magnetic Resonance ◽  
Clinical Outcome ◽  
Phase Contrast ◽  
Flow Dynamics ◽  
Resonance Imaging ◽  
Csf Flow ◽  
Group I ◽  
Group Ii

Abstract Objective Aim of this study is to evaluate the effect of craniospinal interventions on cerebrospinal fluid (CSF) flow hydrodynamics and study the correlation of postoperative changes in flow alteration with clinical outcome. Materials and Methods Fifty patients who underwent various craniospinal procedures were studied using conventional and phase-contrast magnetic resonance imaging (PCMRI) protocol. CSF flow quantification was performed at cerebral aqueduct, foramen magnum, C2–3, and D12–L1 vertebral levels with site showing maximal alteration of CSF flow dynamics considered as the region of interest. Velocity encoding was kept at 20 cm/s. Patients with pathology atcraniovertebral junction were considered separately (group I) from others (group II) due to different flow dynamics. Follow-up scans were performed after an interval of 1 month for temporal evaluation of changes in CSF flow dynamics. Results Patients in both groups showed a significant change in peak CSF velocity postoperatively (mean change of 1.34 cm/s in group I and 0.28 cm/s in group II) with bidirectional improvement in flow on cine-phase-contrast qualitative images. Regional pain (82%) and headache (46%) were seen in most of the patients preoperatively. Postoperatively clinical symptoms improved in 59.5%, static in 26.2%, and worsened in 14.3%. In both the groups, an improvement in clinical symptomatology had significant correlation with mean changes in peak CSF velocity postoperatively (p = 0.04 in both groups). Conclusion PCMRI can effectively evaluate changes in CSF flow noninvasively both pre- and postoperatively. This may have potential role in determining clinical outcome and prognosis of patients undergoing procedures in craniospinal axis.

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