Passive MRI-guided tracking of metallic objects using artifact-reduced imaging with selective excitation

US10139459B2 · kind B2 · utility

Assignee

• The Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Hans Weber · Glückstadt, DE
• Brian A. Hargreaves · Menlo Park, US

Key dates

• Filing date: Mar 30, 2017
• Grant date: Nov 27, 2018
• Expiry date: Aug 17, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/56536
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method using 2D multi-spectral imaging (2DMSI) for MRI imaging of a metallic object (such as a biopsy needle) and region surrounding the metallic object within an imaging field of view of an MRI apparatus includes segmenting the imaging field-of-view into spatial-spectral bins, where the segmenting is based on off-resonance frequency induced by the metallic object and slice location; selectively exciting each frequency bin of the spatial-spectral bins by inverting a slice selection gradient between excitation and refocusing pulses; performing repeated acquisition with different radiofrequency modulations to produce acquired images of adjacent bins; composing a 2DMSI image by root-sum-of-squares combination of the acquired images of adjacent bins; and highlighting in the 2DMSI image an area of furthest off-resonance bins based on 2DMSI off-resonance information by thresholding image intensity in frequency bins, thereby indicating a contour of the metallic object.