High‐resolution ZTE imaging of human teeth

Weiger, Markus; Pruessmann, Klaas P.; Bracher, Anna-Katinka; Köhler, Sascha; Lehmann, Volker; Wolfram, Uwe; Hennel, Franciszek; Rasche, Volker

doi:10.1002/nbm.2783

Cited by 117 publications

(100 citation statements)

References 35 publications

(45 reference statements)

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“…Zero TE (ZTE) (Hafner, 1994; Madio and Lowe, 1995; Weiger et al, 2012; Weiger et al, 2011) could be considered as an alternative to MB-SWIFT. RF pulses used in ZTE consist of a single short hard pulse whereas in MB-SWIFT the pulses are formed of gapped frequency swept chirp pulses with acquisition within the gaps.…”

Section: Discussionmentioning

confidence: 99%

MB-SWIFT functional MRI during deep brain stimulation in rats

et al. 2017

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Recently introduced 3D radial MRI pulse sequence entitled Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) having inherently zero acquisition delay was used to obtain functional MRI (fMRI) contrast in rat’s brain at 9.4 Tesla during deep brain stimulation (DBS). The results demonstrate that MB-SWIFT allows images free of susceptibility artefacts, and provides an excellent fMRI activation contrast in the brain. Flip angle dependence of the MB-SWIFT fMRI signal and elimination of the fMRI contrast while using saturation bands, indicate a blood flow origin of the observed fMRI contrast. MB-SWIFT fMRI modality permits activation studies in the close proximity to the implanted lead, which is not possible to achieve with conventionally used gradient echo and spin echo - echo planar imaging fMRI techniques. We conclude that MB-SWIFT fMRI is a powerful imaging modality for investigations of functional responses during DBS.

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Section: Discussionmentioning

confidence: 99%

MB-SWIFT functional MRI during deep brain stimulation in rats

et al. 2017

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“…Gradient-echo sequences with short TEs of approximately 2-4 msec are also able to capture signal from some parts of the CEP (30), although it is unlikely to capture signals from the calcified CEP. There are several other experimental MR techniques for capturing short T2 signals, such as SWIFT (swept imaging with Fourier transformation) (31) and zero TE imaging (32), which may also be useful for future evaluation of the CEP.…”

Section: Identification Of the Tissue Source Of Signal Intensitymentioning

confidence: 99%

Morphology of the Cartilaginous Endplates in Human Intervertebral Disks with Ultrashort Echo Time MR Imaging

Bae¹,

Statum²,

Zhang³

et al. 2013

Radiology

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Purpose:To image human disk-bone specimens by using conventional spin-echo (SE) and ultrashort echo time (TE) techniques, to describe the morphology at magnetic resonance (MR) imaging, and to identify tissue components contributing to high signal intensity near the cartilaginous endplates (CEPs). Materials and Methods:This study was exempt from institutional review board approval, and informed consent was not required. Five cadaveric lumbar spines (mean age, 61 years 6 11) were prepared into six sample types containing different combinations of disk, uncalcified CEP, calcified CEP, and subchondral bone components and were imaged with proton density-weighted SE (repetition time msec/TE msec, 2000/15) and ultrashort TE (300/0.008, 6.6, echo-subtraction) sequences. Images were evaluated to determine the presence of intermediate-to-high signal intensity in regions excluding the bone marrow. Logistic regression was used to determine which tissue components were significant predictors of the presence of signal intensity for each MR technique. Results:On ultrashort TE MR images, intact disk/uncalcified CEP/ calcified CEP/bone samples exhibited bilaminar intermediate-to-high signal intensity in the region near the CEP, consistent with the histologic appearance of uncalcified and calcified CEPs. Conversely, proton density-weighted SE images exhibited low signal intensity in this region.Results of logistic regression suggested that the presence of uncalcified CEP (P = .023) and calcified CEP (P = .007) in the sample were strong predictors of the presence of signal intensity on ultrashort TE images, whereas the disk was the only predictor (P , .001) of signal intensity on proton density-weighted SE images. Conclusion:Ultrashort TE imaging, unlike proton density-weighted SE imaging, enabled direct visualization of the uncalcified and calcified CEP. Evaluation of the morphology and identification of sources of signal intensity at ultrashort TE MR imaging provides opportunities to potentially aid in the understanding of degenerative disk disease.q RSNA, 2012

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“…With the proposed approach, ZTE imaging operated at lower peak power, longer pulse duration, larger flip angle or higher readout bandwidth becomes practical on clinical imagers, thus providing new opportunities for short- T 2 imaging. While the majority of short- T 2 imaging reported so far in the literature [1–3] has been by UTE MRI, there is both theoretical and experimental evidence that ZTE achieves superior SNR [7, 25]. The need for prolonged RF pulses is particularly stringent when the method is combined with soft-tissue suppression preparation pulses.…”

Section: Discussionmentioning

confidence: 99%

Correction of Excitation Profile in Zero Echo Time (ZTE) Imaging Using Quadratic Phase-Modulated RF Pulse Excitation and Iterative Reconstruction

Li¹,

Magland²,

Seifert³

et al. 2014

IEEE Trans. Med. Imaging

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Zero-echo Time (ZTE) imaging is a promising technique for magnetic resonance imaging (MRI) of short-T2 tissue nuclei in tissues. A problem inherent to the method currently hindering its translation to the clinic is the presence of a spatial encoding gradient during excitation, which causes the hard pulse to become spatially selective, resulting in blurring and shadow artifacts in the image. While shortening radiofrequency (RF) pulse duration alleviates this problem the resulting elevated RF peak power and specific absorption rate (SAR) in practice impede such a solution. In this work, an approach is described to correct the artifacts by applying quadratic phase-modulated RF excitation and iteratively solving an inverse problem formulated from the signal model of ZTE imaging. A simple pulse sequence is also developed to measure the excitation profile of the RF pulse. Results from simulations, phantom and in vivo studies, demonstrate the effectiveness of the method in correcting image artifacts caused by inhomogeneous excitation. The proposed method may contribute toward establishing ZTE MRI as a routine 3D pulse sequence for imaging protons and other nuclei with quasi solid-state behavior on clinical scanners.

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High‐resolution ZTE imaging of human teeth

Cited by 117 publications

References 35 publications

MB-SWIFT functional MRI during deep brain stimulation in rats

MB-SWIFT functional MRI during deep brain stimulation in rats

Morphology of the Cartilaginous Endplates in Human Intervertebral Disks with Ultrashort Echo Time MR Imaging

Correction of Excitation Profile in Zero Echo Time (ZTE) Imaging Using Quadratic Phase-Modulated RF Pulse Excitation and Iterative Reconstruction

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