Method of accurate and rapid NMR imaging of computed T.sub.1 and spin density
First Claim
1. An NMR method of imaging a predetermined region of a sample positioned in a homogeneous magnetic field so as to produce a net longitudinal magnetization in said region, which method comprises:
- subjecting said predetermined region, in the course of a complete scan to obtain data to image said region, to a plurality of repetitions of a sequence composed of rotating magnetic field and magnetic-field-gradient pulses, each repetition of said sequence including at least one step of reducing said longitudinal magnetization to substantially zero;
allowing said longitudinal magnetization to recover along the direction of said homogeneous magnetic field for a recovery time Td ;
exciting nuclear spins in said predetermined region so as to produce at least one NMR spin-echo signal due primarily to said recovered longitudinal magnetization; and
sampling said spin-echo signal in the presence of at least one magnetic-field gradient for encoding spatial information into said spin-echo signals.
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Abstract
A method is provided for accurate and rapid NMR imaging of computed T1 and Mo (spin density) NMR images. The imaging data is acquired using a repetition of a sequence made up of RF and magnetic-field-gradient pulses. Each repetition of the sequence includes at least one step of reducing the net longitudinal magnetization in a predetermined region of the sample to zero. The longitudinal magnetization is allowed to at least partially recover prior to exciting nuclear spins in the predetermined region to produce at least one NMR spin-echo signal due primarily to the recovered magnetization. The spin-echo signal is sampled in the presence of a magnetic-field gradient for encoding spatial information.
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Citations
12 Claims
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1. An NMR method of imaging a predetermined region of a sample positioned in a homogeneous magnetic field so as to produce a net longitudinal magnetization in said region, which method comprises:
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subjecting said predetermined region, in the course of a complete scan to obtain data to image said region, to a plurality of repetitions of a sequence composed of rotating magnetic field and magnetic-field-gradient pulses, each repetition of said sequence including at least one step of reducing said longitudinal magnetization to substantially zero; allowing said longitudinal magnetization to recover along the direction of said homogeneous magnetic field for a recovery time Td ; exciting nuclear spins in said predetermined region so as to produce at least one NMR spin-echo signal due primarily to said recovered longitudinal magnetization; and sampling said spin-echo signal in the presence of at least one magnetic-field gradient for encoding spatial information into said spin-echo signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification