
doi: 10.1002/mrm.23017
pmid: 21721039
AbstractSequences with ultrashort echo times enable new applications of MRI, including bone, tendon, ligament, and dental imaging. In this article, a sequence is presented that achieves the shortest possible encoding time for each k‐space point, limited by pulse length, hardware switching times, and gradient performance of the scanner. In pointwise encoding time reduction with radial acquisition (PETRA), outer k‐space is filled with radial half‐projections, whereas the centre is measured single pointwise on a Cartesian trajectory. This hybrid sequence combines the features of single point imaging with radial projection imaging. No hardware changes are required. Using this method, 3D images with an isotropic resolution of 1 mm can be obtained in less than 3 minutes. The differences between PETRA and the ultrashort echo time (UTE) sequence are evaluated by simulation and phantom measurements. Advantages of pointwise encoding time reduction with radial acquisition are shown for tissue with a T2 below 1 ms. The signal to noise ratio and Contrast‐to‐noise ratio (CNR) performance, as well as possible limitations of the approach, are investigated. In‐vivo head, knee, ankle, and wrist examples are presented to prove the feasibility of the sequence. In summary, fast imaging with ultrashort echo time is enabled by PETRA and may help to establish new routine clinical applications of ultrashort echo time sequences. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Ligaments, Time Factors, Fourier Analysis, Phantoms, Imaging, Image Enhancement, Magnetic Resonance Imaging, Sensitivity and Specificity, Bone and Bones, Tendons, Image Processing, Computer-Assisted, Humans, Head
Ligaments, Time Factors, Fourier Analysis, Phantoms, Imaging, Image Enhancement, Magnetic Resonance Imaging, Sensitivity and Specificity, Bone and Bones, Tendons, Image Processing, Computer-Assisted, Humans, Head
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 313 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 1% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 1% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 1% |
