Mr-based attenuation correction in pet/mr imaging with dixon pulse sequence

Abstract

A medical imaging system (10) includes a nuclear imaging system (62), a timing optimization unit (40), a magnetic resonance (MR) scanner (12), an MR reconstruction unit (38), and an attenuation map unit (50). The nuclear imaging system (62) receives nuclear decay data and generates at least one nuclear image (64) of a first resolution based on the received nuclear decay data of an imaged subject (16) and an attenuation map (52). The timing optimization unit (40) which selects a first and a second echo time for a modified Dixon (mDixon) pulse sequence and a sufficient number of repetition times (TRs) to generate an image of the subject (16) of at least a first resolution, with the phase angle difference between water and fat at the first and the second echo time being unequal to 0 and 180degrees. The MR scanner (12) applies the sequence to the subject (16) and receives MR data (32) from the subject. The MR reconstruction unit (38) reconstructs at least one MR image (44) based on the MR data (32). The attenuation map unit (50) constructs the attenuation map (52) based on the reconstructed MR image (44).

Description

technical field [0001] The following generally relates to medical imaging. It finds particular application in conjunction with magnetic resonance (MR) imaging to provide attenuation correction for positron emission tomography (PET) imaging, and will be described with particular reference thereto. However, it should be understood that there are also specific applications and other usage scenarios, and are not necessarily limited to the above-mentioned applications. Background technique [0002] In PET imaging, subjects are injected with radiopharmaceuticals that are targeted to specific tissues by uptake, usually based on metabolic activity. When the radiopharmaceutical decays, positrons annihilated in contact with electrons are emitted to form a pair of photons emitted at opposite 180° along the line of response (LOR). The emitted gamma photons are recorded by PET detectors surrounding the object. The location of the annihilation event is calculated from the recorded gamm...

AI Technical Summary

Problems solved by technology

[0005] In the Dixon technique, a long TR (repetition time) may be experienced, which results in long data acquisition times

For example, when imaging the location of a whole-body image, the time required to collect all the data exceeds the ability of a typical subject to maintain his or her breathing, leading to image artifacts caused by breathing motion, and thus resulting in Tissue misclassification in the decay map of

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