Spatially resolved flow velocity measurements and projection angiography by adiabatic passage

Lee, H.K.; Nalcioğlu, Orhan; Moran, P. R.

doi:10.1016/0730-725x(91)90105-u

Cited by 16 publications

(8 citation statements)

References 37 publications

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“…1 has been shown to be valid even under partially relaxed conditions (11). We use the principle of transport-induced adiabatic fast passage (18)(19)(20)(21) to continuously invert blood entering the brain. In this approach, constant low-amplitude irradiation is applied off-resonance in the presence of a magnetic field gradient.…”

Section: Methodsmentioning

confidence: 99%

Quantitative magnetic resonance imaging of human brain perfusion at 1.5 T using steady-state inversion of arterial water.

Roberts

Detre

Bolinger

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

167

106

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We report our experience using a noninvasive magnetic resonance technique for quantitative imaging of human brain perfusion at 1.5 T. This technique uses magneticafy inverted arterial water as a freely diffusible blood flow tracer. A perfusion image is calculated from magnetic resonance images acquired with and without arterial blood inversion and from an image of the apparent spin-lattice relaxation time. Single-slice perfusion maps were obtained from nine volunteers with approximately 1 x 2 x 5-mm resolution in an acquisition time of 15 min. Analysis yielded average perfusion rates of 93 + 16 ml 100 g-l-min'1 for gray matter, 38 ± 10 ml 100 g'i.min-1 for white matter, and 52 ± 8 ml 100 g'l min-I for whole brain. Significant changes in perfusion were observed during hyperventilation and breath holding. This technique may be used for quantitative measurement of perfusion in human brain without the risks and expense of methods which use exogenous tracers.

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Section: Methodsmentioning

confidence: 99%

Quantitative magnetic resonance imaging of human brain perfusion at 1.5 T using steady-state inversion of arterial water.

Roberts

Detre

Bolinger

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

167

106

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show abstract

“…I P is the adiabatic inversion period, and I D is the post inversion relaxation period. The application of the RF pulses on different axes represents the primary deviation of this sequence from a standard spin echo sequence the experiments reported by Lee et al 20 and Zhang et al, 4 and has been recently reported. 21 For this measurement, a transverse image is acquired distal to the inversion plane (`1 cm) demonstrating the internal carotid arteries after a short period of inversion (250-300 ms).…”

Section: Methodsmentioning

confidence: 87%

Rapid and continuous monitoring of cerebral perfusion by magnetic resonance line scan assessment with arterial spin tagging

et al. 1999

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A new approach is presented for rapid and continuous monitoring of cerebral perfusion which is based upon line‐scan MR column imaging with arterial spin tagging (AST) of endogenous water. Spin tagging of arterial water protons is accomplished using adiabatic fast passage inversion, followed by acquisition of the perfusion sensitive MR signal from a column placed at the desired level through the brain using line scan localization techniques. A perfusion sensitive line scan is followed by a non‐perfusion sensitive line scan, and perfusion is calculated pixel‐by‐pixel from the intensity difference of the two lines. Continuous perfusion measurements are reported with temporal resolution of 10 s in pixels of volume 0.027 cm3 or less. Examples of the methodology are given during hypercapnic challenge induced with carbon dioxide, and during an ischemic event induced by reversible middle cerebral artery occlusion. The method is also used to characterize the signal response as a function of arterial inversion time and post inversion acquisition delay. These methods permit rapid and continuous monitoring of cerebral perfusion with high spatial resolution, and can be interleaved with MR measurements of diffusion and T1 to follow the progression of cerebral events during physiological or pharmacological intervention. Copyright © 1999 John Wiley & Sons, Ltd.

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“…where G z is the magnetic field gradient strength, V z is the velocity of the spin perpendicular to the labeling plane, g is the gyromagnetic ratio, and H 1 is the field strength of the inversion pulse (9). The degree of inversion achieved by the off-resonance RF radiation is described by:…”

Section: Introductionmentioning

confidence: 99%

Magnetization transfer effects on the efficiency of flow‐driven adiabatic fast passage inversion of arterial blood

et al. 2007

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Continuous arterial spin labeling experiments typically use flow-driven adiabatic fast passage inversion of the arterial blood water protons. In this article, we measure the effect of magnetization transfer in blood and how it affects the inversion label. We use modified Bloch equations to model flow-driven adiabatic inversion in the presence of magnetization transfer in blood flowing at velocities from 1 to 30 cm/s in order to explain our findings. Magnetization transfer results in a reduction of the inversion efficiency at the inversion plane of up to 3.65% in the range of velocities examined, as well as faster relaxation of the arterial label in continuous labeling experiments. The two effects combined can result in inversion efficiency reduction of up to 8.91% in the simulated range of velocities. These effects are strongly dependent on the velocity of the flowing blood, with 10 cm/s yielding the largest loss in efficiency due to magnetization transfer effects. Flowing blood phantom experiments confirmed faster relaxation of the inversion label than that predicted by T(1) decay alone.

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Spatially resolved flow velocity measurements and projection angiography by adiabatic passage

Cited by 16 publications

References 37 publications

Quantitative magnetic resonance imaging of human brain perfusion at 1.5 T using steady-state inversion of arterial water.

Quantitative magnetic resonance imaging of human brain perfusion at 1.5 T using steady-state inversion of arterial water.

Rapid and continuous monitoring of cerebral perfusion by magnetic resonance line scan assessment with arterial spin tagging

Magnetization transfer effects on the efficiency of flow‐driven adiabatic fast passage inversion of arterial blood

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