Imaging-based diagnostic apparatus and methods for quantifying cerebral vascular reserve

• US 9,140,771 B2
• Filed: 02/24/2012
• Issued: 09/22/2015
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: Northwestern University
• Original Assignee: Northwestern University
• Inventors: Carroll, Timothy J., Hurley, Michael, Vakil, Parmede, Menon, Rajiv, Jonathan, Sumeeth Vijay, Qian, Renee, Ansari, Sameer
• Primary Examiner(s): Brutus, Joel F
• Application Number:
  US13/405,126
• Publication Number:
  US 20120220858A1
• Time in Patent Office: 1,306 Days
• Field of Search: 600/407, 600/410, 600/420
• US Class Current: 1/1
• CPC Class Codes: A61B 2576/026 for the brain
• CPC Class Codes: A61B 5/0042 for the brain
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01R 33/5602 by filtering or weighting based on different relaxation times within the sample, e.g. T1 weighting using an inversion pulse
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/56366 Perfusion imaging
• CPC Class Codes: G16H 30/40 for processing medical images, e.g. editing

Abstract

In one aspect of the disclosure, an MRI-based system includes an MRI scanner having a first axis and a first plane perpendicular to the first axis, a pulse sequence module configured to provide a 3D pulse sequence to the MRI scanner, and a control module configured to instruct the MRI scanner to conduct radial k-space samples having N second planes that each are perpendicular to the first plane and through which the first axis passes, N being an integer greater than 1. The 3D pulse sequence instructs the MRI scanner to a radio-frequency (RF) pulse, conduct a gradient readout in the first plane, and conduct a gradient readout in one of the N second planes.

Claims

1. A magnetic resonance imaging (MRI) system, comprising:

an MRI scanner that has a first axis and a first plane perpendicular to said first axis, and that comprises a radio-frequency (RF) antenna arrangement and a gradient coil arrangement;

a control computer configured to operate the MRI scanner in a first execution of a 3D pulse sequence to radiate an RF pulse with said RF antenna arrangement to produce a first excitation of nuclear spins in an examination subject and to thereafter acquire first raw data from the examination subject representing magnetic resonance signals produced by said first excitation of said nuclear spins, and to generate magnetic gradient fields with said gradient coil arrangement that cause respective samples of said first raw data to be entered into 3D k-space in N second planes that are each perpendicular to said first plane and through which said first axis passes, with said N second planes thereby being radial planes in 3D k-space, with N being an integer greater than 1, thereby producing a first set of 3D k-space data;

a stress-inducing unit configured to interact with the examination subject in the MRI scanner to induce a physiological stress in the examination subject after acquiring said first 3D k-space data set;

said control computer being configured to operate the MRI scanner to execute a repetition of said 3D pulse sequence, including radiating a second RF pulse, after inducing said physiological stress in the examination subject, to produce a second excitation of nuclear spins in the examination subject, and to enter samples of second raw data, resulting from said second excitation, into 3D k-space in said N second planes, thereby producing a second 3D k-space data set;

an image reconstruction computer provided with said first 3D k-space data set and said second 3D k-space data set, and configured to reconstruct a first image of the examination subject from said first 3D k-space data set and to reconstruct a second image of the examination subject from said second 3D k-space data set;

said image reconstruction computer being configured to bring said first image and said second image into registration with each other and to identify at least one cerebral blood indicator, selected from the group consisting of cerebral blood flow and cerebral blood volume, in said first image and said second image in registration with each other and to reconstruct a cardiovascular reserve (CVR) image as a quotient having a numerator which is a difference of said at least one cerebral blood indicator in said first image subtracted from said at least one cerebral blood indicator in said second image, and a denominator which is said cerebral blood indicator in said first image multiplied by 100%; and

said image reconstruction computer being configured to make said CVR image available at an output of said image reconstruction computer in electronic form, as a data file.

2. The MRI system of claim 1, wherein the quantification module is configured to implement the following calibration equation:

3. An MRI system as claimed in claim 1 wherein said control computer is configured to operate said gradient coil arrangement of said MRI scanner in said 3D pulse sequence to generate said gradient magnetic fields to produce a sampling window in said 3D pulse sequence, in which said samples of said first raw data are acquired and to produce a sampling window in said repetition of said 3D pulse sequence, in which said samples of said second raw data are acquired, with each sampling window having a duration in a range between 10,000 ms and 10 seconds.

4. An MRI system as claimed in claim 1 wherein said control computer is configured to operate said MRI gradient coil arrangement of said scanner in said 3D pulse sequence, and in said repetition of said 3D pulse sequence, to generate said gradient magnetic fields to respectively acquire said samples of said first raw data of said first raw data and said samples of said second raw data each with a spatial resolution of about 2.5 mm×

0.825 mm×

0.825 mm.

5. An MRI system as claimed in claim 1 wherein said control computer is configured to operate said MRI scanner, and said image reconstruction computer is configured to reconstruct said first image and said second image, so as to cause said first image and said second image to be reconstructed at a rate of about 0.6 second/image.