Magnetic resonance imaging of bone tissue

• US 9,504,851 B2
• Filed: 06/18/2012
• Issued: 11/29/2016
• Est. Priority Date: 06/27/2011
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Franke, Jochen Frederik, Meltsner, Michael Adam, Schulz, Volkmar, Kotys, Melanie Suzanne, Warner, Lizette
• Primary Examiner(s): Chen, Tse
• Assistant Examiner(s): HOFFMAN, JOANNE M
• Application Number:
  US14/126,979
• Publication Number:
  US 20140221816A1
• Time in Patent Office: 1,625 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/4417 related to combined acquisition of different diagnostic modalities
• CPC Class Codes: A61B 8/0875 for diagnosis of bone A61B5/4504 takes precedence
• CPC Class Codes: A61B 8/5261 combining images from different diagnostic modalities, e.g. ultrasound and X-ray
• CPC Class Codes: A61N 2005/1052 using positron emission tomography [PET] single photon emission computer tomography [SPECT] imaging
• CPC Class Codes: A61N 2005/1055 using magnetic resonance imaging [MRI]
• CPC Class Codes: A61N 2005/1062 using virtual X-ray images, e.g. digitally reconstructed radiographs [DRR]
• CPC Class Codes: A61N 5/1039 using functional images, e.g. PET or MRI
• CPC Class Codes: G01R 33/4808 Multimodal MR, e.g. MR combined with positron emission tomography [PET], MR combined with ultrasound or MR combined with computed tomography [CT]
• CPC Class Codes: G01R 33/481 MR combined with positron emission tomography [PET] or single photon emission computed tomography [SPECT]
• CPC Class Codes: G01R 33/4816 NMR imaging of samples with ultrashort relaxation times such as solid samples, e.g. MRI using ultrashort TE [UTE], single point imaging, constant time imaging
• CPC Class Codes: G01R 33/4828 Resolving the MR signals of different chemical species, e.g. water-fat imaging
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI

Abstract

A medical apparatus includes a magnetic resonance imaging system for acquiring magnetic resonance data from an imaging volume, a processor for controlling the medical apparatus, and a memory containing machine executable instructions and a pulse sequence. The magnetic resonance data acquired using the pulse sequence comprises free induction decay data and multiple gradient echo data. Execution of the instructions causes the processor to acquire the magnetic resonance data using the magnetic resonance imaging system in accordance with the pulse sequence, and reconstruct an in-phase image, a fat-saturated image, a water-saturated image, and an ultra-short echo time image from the magnetic resonance data, wherein the ultra-short echo time image comprises bone image data.

Claims

1. A medical apparatus comprising:

a magnetic resonance imaging system which acquires magnetic resonance data from an imaging volume;

a processor for controlling the medical apparatus; and

a memory containing machine executable instructions and a pulse sequence for a single acquisition, wherein the magnetic resonance data acquired using the pulse sequence comprises free induction decay data and multiple gradient echo data, wherein execution of the instructions causes the processor to;

acquire the magnetic resonance data using the magnetic resonance imaging system in accordance with the pulse sequence in a single acquisition; and

reconstruct an in-phase image comprising an image with fat and water signals in phase, a fat-saturated image, a water-saturated image, and an ultra-short echo time image from the magnetic resonance data acquired in the single acquisition, wherein the ultra-short echo time image comprises bone image data,

construct a medullary bone image from the water-saturated image;

construct a cortical bone image by subtracting the in-phase image from the ultra-short echo time image;

construct a complete bone image by adding the medullary bone image to the cortical bone image, and

calculate a spatially dependent radiation attenuation coefficient using anatomical information retrieved from the complete bone image, the fat-saturated image, the in-phase image, and the ultra-short echo time image.

2. The medical apparatus of claim 1, wherein the ultra-short echo time image is used for differentiating bone and air, wherein the in-phase image is used for image segmentation, and wherein the fat saturated image is used for image segmentation.

3. The medical apparatus of claim 2, wherein further execution of the instructions causes the processor to:

display the fat-saturated image, the in-phase image, the complete bone image and the ultra-short echo time image on a graphical user interface; and

receive radiation therapy planning data from the graphical user interface.

4. The medical apparatus of claim 1, wherein execution of the instructions further causes the processor to generate radiation therapy planning data using the fat-saturated image, the in-phase image, the ultra-short echo time image, the complete bone image, the spatially dependent radiation attenuation coefficient, and a treatment plan with a radiation therapy planning program module.

5. The medical apparatus of claim 4, wherein the medical apparatus further comprises a radiation therapy system, wherein the execution of the instructions further causes the processor to:

generate radiation therapy control commands using the radiation therapy planning data; and

treat the subject with the radiation therapy system by executing the radiation therapy control commands.

6. The medical apparatus of claim 5, wherein the radiation therapy system is any one of the following:

a linear accelerator, a gamma knife, a charged particle therapy system, a proton therapy system, an x-ray therapy system, external beam radiation system, and a brachytherapy system.

7. The medical apparatus of claim 1, wherein execution of the instructions further causes the processor to:

receive radio-isotope imaging data, and

calculate a medical image using the radio-isotope image data and the spatially dependent radiation attenuation coefficient.

8. The medical apparatus of claim 7, wherein the medical apparatus further comprises a radio-isotope imaging system for acquiring the radio-isotope imaging data, wherein the radio-isotope imaging system is any one of the following:

a positron emission tomography system and a single photon emission computed tomography system, and wherein execution of the instructions further causes the processor to acquire the radio-isotope imaging data using the radio-isotope imaging system.

9. The medical apparatus of claim 1, wherein execution of the instructions further causes the processor to reconstruct an opposed phase image comprising an image with fat and water signals 180 degrees out of phase from the magnetic resonance data.

10. The medical apparatus of claim 1, wherein execution of the instructions further causes the processor to reconstruct multiple echo images, wherein the in-phase image, the fat-saturated image, the water-saturated image, and the ultra-short echo time image are reconstructed from the multiple echo images using a Dixon signal model.

11. The medical apparatus of claim 1, wherein execution of the instructions further causes the processor to construct a digital reconstructed radiograph image based on the cortical bone image.

12. The medical apparatus of claim 11, wherein the digital reconstructed radiograph image is used for 2-dimensional patient matching with a support positioning system.

13. A method of operating a medical apparatus, wherein the medical apparatus comprises a magnetic resonance imaging system for acquiring magnetic resonance data from an imaging volume, wherein the method comprises the steps of:

acquiring the magnetic resonance data in a single acquisition using the magnetic resonance imaging system, wherein the magnetic resonance data acquired in the single acquisition comprises free induction decay data and multiple gradient echo data; and

reconstructing an in-phase image comprising an image with fat and water signals in phase, a fat-saturated image, a water-saturated image, and an ultra-short echo time image from the magnetic resonance data acquired in the single acquisition, wherein the ultra-short echo time image comprises bone image data;

constructing a medullary bone image from the water-saturated image;

constructing a cortical bone image by subtracting the in-phase image from the ultra-short echo time image;

constructing a complete bone image by adding the medullary bone image to the cortical bone image;

performing image segmentation to differentiate at least regions of cortical bone, medullary bone, fat, and air;

calculating a spatially dependent radiation attenuation coefficient using at least anatomical information retrieved from the image segmentation.

14. The method according to claim 13, further including:

constructing a digital reconstructed radiograph image based on a 2-dimensional projection of the ultra-short echo time image.

15. The method according to claim 14, further including:

matching a patient position with a support positioning system in a radiation therapy system in 2-dimensions based on the digital reconstructed radiograph image.

16. The method according to claim 13, wherein the cortical bone image is used to register the images.

17. A non-transitory computer-readable storage medium containing machine readable instructions for execution by a processor controlling a medical apparatus, wherein the medical apparatus comprises a magnetic resonance imaging system for acquiring magnetic resonance data from an imaging volume, wherein the computer-readable storage medium further contains a pulse sequence for controlling the magnetic resonance imaging system, wherein the magnetic resonance data acquired using the pulse sequence comprises free induction decay data and multiple gradient echo data, wherein execution of the instructions causes the processor to:

acquire the magnetic resonance data using the magnetic resonance imaging system; and

reconstruct an in-phase image comprising an image with fat and water signals in phase, a fat-saturated image, a water-saturated image, and an ultra-short echo time image from the magnetic resonance data, wherein the ultra-short echo time image comprises bone image data;

constructing a medullary bone image from the water-saturated image;

constructing a cortical bone image by subtracting the in-phase image from the ultra-short echo time image; and

constructing a complete bone image by adding the medullary bone image to the cortical bone image

calculating a spatially dependent radiation attenuation coefficient using anatomical information retrieved from the complete bone image, the fat-saturated image, the in-phase image, and the ultra-short echo time image.

18. A controller for a medical apparatus, wherein the medical apparatus comprises a magnetic resonance imaging system for acquiring magnetic resonance data from an imaging volume;

wherein the controller is configured to;

acquire the magnetic resonance data using the magnetic resonance imaging system, wherein the controller is arranged to use a pulse sequence to control the operating of the magnetic resonance imaging system during acquisition of the magnetic resonance data, wherein the magnetic resonance data acquired using the pulse sequence comprises free induction decay data and multiple gradient echo data; and

reconstruct at least an in-phase image comprising an image with fat and water signals in phase, a water-saturated image, and an ultra-short echo time image from the magnetic resonance data, wherein the ultra-short echo time image comprises bone image data;

constructing a medullary bone image from the water-saturated image;

constructing a cortical bone image by subtracting the in-phase image from the ultra-short echo time image; and

constructing a complete bone image by adding the medullary bone image to the cortical bone image

calculating a spatially dependent radiation attenuation coefficient using anatomical information retrieved from at least the complete bone image, the in-phase image, and the ultra-short echo time image.