Simulation and experimental verification of the diffusion in an anisotropic fiber phantom. Journal of Magnetic Resonance. MRI phantoms: are there alternatives to agar? PLoS One. Biomimetic phantom for the validation of diffusion magnetic resonance imaging. The searches were done from March to December The key-words applied were: diffusion-weighted imaging, diffusion weighted imaging quality control, diffusion tensor imaging, diffusion tensor imaging quality control, magnetic resonance imaging quality control, medical imaging phantoms, MRI phantoms, DWI artifacts, DTI artifacts and MRI instrumentation.
The articles were organized according the applications and characteristics of phantom, diffusion pattern simulated isotropic or anisotropic , as well as the building methods, materials and results. In addition, the compound that fills them is, generally, an aqueous paramagnetic solution containing CuSO 4 , NiCl 2 , MnCl 2 or GdCl 3 , because of its long-term stability and relaxation time. However, these solutions have T1 very close to T2 except the MnCl 2 , which does not occur in biological tissues.
The results from images of these solutions also depend on the geometry of the container that holds them. Desirable characteristics for a DWI or DTI phantom are covering of a large range of diffusivities, long-term stability, low cost, low toxicity, T1 and T2 values similar to biological tissues, and high viscosity in order to minimize vibration and convective motions effects Kato et al.
Composition of MRI phantom equivalent to human tissues. Medical Physics. Prospective tissue-mimicking materials for use in NMR imaging phantoms. Magnetic Resonance Imaging. Test liquids for quantitative MRI measurements of self-diffusion coefficient in vivo.
There are phantoms of isotropic diffusion for DWI typically spheres or cylinders filled by liquid Laubach et al.
A phantom for diffusion-weighted imaging of acute stroke. Applied Magnetic Resonance. A microfabricated phantom for quantitative MR perfusion measurements: validation of singular value decomposition deconvolution method. Effects of restricted diffusion in a biological phantom: A q-space diffusion MRI study of asparagus stems at a 3T clinical scanner.
Construct and assess multimodal mouse brain connectomes via joint modeling of multi-scale DTI and neuron tracer data. Observation of microscopic diffusion anisotropy in the spinal cord using double-pulsed gradient spin echo MRI. There are gels, for isotropic or anisotropic diffusion studies, whose magnetic properties are similar to healthy or pathological tissue Hellerbach et al.
A quality assurance protocol for diffusion tensor imaging using the head phantom from American College of Radiology. Mathematical framework for simulating diffusion tensor MR neural fiber bundles.
The liquids were measured using a standard 5-mm NMR sample tube. Nonetheless, despite the advantage of these compounds having defined NMR spectral lines, their use in clinical routine is limited by toxicity and inflammability Tofts et al. Non-toxic and stable compounds, such as aqueous solutions of polyvinylpyrrolidone PVP , can be an alternative to agarose or alkanes. PVP showed long-term stability during a 15 months period Pierpaoli et al. Gels whose dielectric relaxation properties have values close to those found for biological tissue have been tested as filling for isotropic diffusion phantoms.
CAG consists of carrageenan as a gelling agent, agarose and GdCl 3 as T2 and T1 modifiers, respectively, in addition to distilled water and the antiseptic NaN 3 , to reduce gel degradation by microbial agents. The concentration of each compound to reach the desirable diffusion properties is defined by an equation set.
It was observed that images of gels had less distortion than images of liquids due to reduction of the macroscopic flow effect. Pathological conditions, such as stroke can also be simulated by gels.
A human brain phantom filled by agar-based gel has been applied to analyze DWI pulse sequences performance to discriminate acute stroke and normal gray matter GM.
Changing the gel concentrations of agarose and sucrose is possible to simulate some properties of biological tissues in MRI T1, T2, ADC-values, for example such as healthy and pathological brain tissues. With this phantom the researchers observed that ADC variation between stroke-like areas and GM was similar to that found in human brain Laubach et al.
Other kind of container used in DWI phantoms is test tubes. There were not significant differences between ADC values of both pulse sequences. Physica Medica. Tubes filled by different concentrations of polyethylene glycol PEG , to control diffusivity, and Gadobutrol, to control T2, were also tested as isotropic diffusion phantoms Gatidis et al.
Development of an MRI phantom for diffusion-weighted imaging with independent adjustment of apparent diffusion coefficient values and T2 relaxation times. From all studies of isotropic diffusion phantoms, the agar or agarose is the most applied compound. The Table 1 summarizes the characteristics of isotropic phantoms proposed in literature. A DTI phantom was made of layers of an agar-based isotropic gel, each layer having a different conductivity.
It was shown that gels make the setup more stable and reduce imaging artifacts due to reduction of the macroscopic water flux Hubbard et al. Polycaprolactone PCL and polyethylene oxide were used to make axon-like structures using the co-electrospinning technique. The phantom was tested in a preclinical 7T MRI scanner a scanner dedicated to studies using small animals , and it was found that MD increases when the fiber diameter increases and FA decreases when the fiber internal diameter increases.
The setup remained stable for 1 month; however, it was a small phantom, incompatible with clinical scanners Hubbard et al. The co-electrospinning technique was also used to develop an anisotropic phantom to simulate cardiac muscle tissue Teh et al.
Phantoms made using lithography and other microfabrication techniques also been reported to be useful for DTI QC and pulse-sequence tests Ebrahimi et al. Pore diameter mapping using double pulsed-field gradient MRI and its validation using a novel glass capillary array phantom.
These fibers have multiple filaments, being more anisotropic than nylon, polyester, polyamide or linen. However, the phantom relaxation times differ from those from biological tissues. P Soc Photo Opt Ins — Implementation of fiber tract navigation. Neurosurgery 58 4 Suppl 2 :ONS—— PubMed Abstract Google Scholar. Intraoperative diffusion-tensor MR imaging: shifting of white matter tracts during neurosurgical procedures — initial experience. Radiology 1 — Intraoperative visualization of the pyramidal tract by diffusion-tensor-imaging-based fiber tracking.
Neuroimage 30 4 — White matter fiber tractography: why we need to move beyond DTI. J Neurosurg 6 — Comparison of compressed sensing diffusion spectrum imaging and diffusion tensor imaging in patients with intracranial masses. Magn Reson Imaging — Converting multi-shell and diffusion spectrum imaging to high angular resolution diffusion imaging. Front Neurosci Identifying preoperative language tracts and predicting postoperative functional recovery using HARDI q-ball fiber tractography in patients with gliomas.
Neuroimage — Mapping the orientation of white matter fiber bundles: a comparative study of diffusion tensor imaging, diffusional kurtosis imaging, and diffusion spectrum imaging.
Functional outcome after language mapping for glioma resection. Functional magnetic resonance imaging for neurosurgical planning in neurooncology.
Eur Radiol 14 7 — Quantitative fMRI assessment of the differences in lateralization of language-related brain activation in patients with temporal lobe epilepsy. Neuroimage 18 2 — Preoperative blood oxygen level-dependent functional magnetic resonance imaging in patients with primary brain tumors: clinical application and outcome.
Neurosurgery 54 4 — Applications of fMRI in translational medicine and clinical practice. Nat Rev Neurosci 7 9 — Can fMRI safely replace the Wada test for preoperative assessment of language lateralisation?
A meta-analysis and systematic review. J Neurol Neurosurg Psychiatry 85 5 —8. Seghier ML. Laterality index in functional MRI: methodological issues. Magn Reson Imaging 26 5 — Brain Pt 10 — Impact of preoperative functional magnetic resonance imaging during awake craniotomy procedures for intraoperative guidance and complication avoidance. Stereotact Funct Neurosurg 92 5 — Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery.
Neurosurg Focus 38 1 :E3. Presurgical fMRI and DTI for the prediction of perioperative motor and language deficits in primary or metastatic brain lesions.
J Neuroimaging 25 5 — Intraoperative assistive technologies and extent of resection in glioma surgery: a systematic review of prospective controlled studies. Neurosurg Rev 38 2 — Bookheimer S. Pre-surgical language mapping with functional magnetic resonance imaging. Neuropsychol Rev 17 2 — Tharin S, Golby A. Functional brain mapping and its applications to neurosurgery.
Neurosurgery 60 4 Suppl 2 — Technical principles in glioma surgery and preoperative considerations. J Neurooncol 2 — Resting-state fMRI: a review of methods and clinical applications. Spontaneous fluctuations in brain activity observed with functional magnetic resonance imaging. Nat Rev Neurosci 8 9 — Magn Reson Imaging 24 8 — Preoperative sensorimotor mapping in brain tumor patients using spontaneous fluctuations in neuronal activity imaged with functional magnetic resonance imaging: initial experience.
Neurosurgery 65 6 Suppl — Mapping sensorimotor cortex with slow cortical potential resting-state networks while awake and under anesthesia. Neurosurgery 71 2 — A novel data-driven approach to preoperative mapping of functional cortex using resting-state functional magnetic resonance imaging.
Neurosurgery 73 6 — Neuroimage Clin — Clinical resting-state fMRI in the preoperative setting: are we ready for prime time? Top Magn Reson Imaging 25 1 —8. Presurgical brain mapping of the language network in patients with brain tumors using resting-state fMRI: comparison with task fMRI.
Hum Brain Mapp 37 3 — Defining language networks from resting-state fMRI for surgical planning — a feasibility study. Hum Brain Mapp 35 3 — Ultra-high field MRI: advancing systems neuroscience towards mesoscopic human brain function. Neuroimage Kim M, Kim HS. Emerging techniques in brain tumor imaging: what radiologists need to know.
Korean J Radiol 17 5 — Differentiation of glioblastoma multiforme and single brain metastasis by peak height and percentage of signal intensity recovery derived from dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging.
Perfusion and diffusion MR imaging in enhancing malignant cerebral tumors. Eur J Radiol 58 3 — Differentiation of primary central nervous system lymphoma and high-grade glioma with dynamic susceptibility contrast-enhanced perfusion magnetic resonance imaging. Acta Radiol 50 2 — Differentiation of primary central nervous system lymphomas and glioblastomas: comparisons of diagnostic performance of dynamic susceptibility contrast-enhanced perfusion MR imaging without and with contrast-leakage correction.
Percentage signal recovery derived from MR dynamic susceptibility contrast imaging is useful to differentiate common enhancing malignant lesions of the brain. Can proton MR spectroscopic and perfusion imaging differentiate between neoplastic and nonneoplastic brain lesions in adults?
Glioma grading: sensitivity, specificity, positive and negative predictive values of diffusion and perfusion imaging. J Neurooncol 94 1 — Glioma grading: sensitivity, specificity, and predictive values of perfusion MR imaging and proton MR spectroscopic imaging compared with conventional MR imaging. Using relative cerebral blood flow and volume to evaluate the histopathologic grade of cerebral gliomas: preliminary results.
Is volume transfer coefficient K trans related to histologic grade in human gliomas? Correlation of volume transfer coefficient Ktrans with histopathologic grades of gliomas. J Magn Reson Imaging 36 2 — Dynamic contrast-enhanced and dynamic susceptibility contrast perfusion MR imaging for glioma grading: preliminary comparison of vessel compartment and permeability parameters using hotspot and histogram analysis. Eur J Radiol 85 6 — The added value of apparent diffusion coefficient to cerebral blood volume in the preoperative grading of diffuse gliomas.
Low-grade gliomas: do changes in rCBV measurements at longitudinal perfusion-weighted MR imaging predict malignant transformation? To reduce errors due to crossing, kissing, or branching fibers, a minimum of 20 diffusion directions should be obtained with 64 or more preferred.
If FA values are compared to normal data bases, it is critical that multiple comparison e. FA EN. National Brain Mapping Lab. Remember me. Don't have an account?
Register now.
0コメント