# US 11,112,474 B2 · Magnetic resonance imaging apparatus and magnetic resonance imaging method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,112,474 B2 - Document ID: US11112474B2 - Status: Granted - Kind: B2 - Application number: 16/532,673 - Filed: 2019-08-06 - Published: 2020-02-06 - Granted: 2021-09-07 - Earliest claimed: 2018-08-06 - Assignees: Canon Medical Systems Corporation - Applicants: Canon Medical Systems Corporation - Inventors: Shuhei Nitta; Naho Imamura; Takahiro Ohmure; Hiroshi Takai; Nobuyasu Ichinose; Yoshimori Kassai - Web page: https://patentgrep.com/patent/US11112474B2 ## CPC - G01R 33/4828: {Resolving the MR signals of different chemical species, e.g. water-fat imaging} - G01R 33/543: {Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription (G01R33/546 takes precedence)} - G01R 33/5607: {by reducing the NMR signal of a particular spin species, e.g. of a chemical species for fat suppression, or of a moving spin species for black-blood imaging} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract According to one embodiment, a magnetic resonance imaging apparatus includes processing circuitry. The processing circuitry acquires a first resonance frequency distribution of a first tissue and a second resonance frequency distribution of a second tissue which is different from the first tissue. The processing circuitry calculates a center frequency of a frequency-selective pulse that suppresses or emphasizes either one of the first tissue and the second tissue in accordance with the first and second resonance frequency distributions. The processing circuitry collects a magnetic resonance signal after the frequency-selective pulse is applied at the calculated center frequency. ## Claims ### Claim 1 A magnetic resonance imaging apparatus comprising processing circuitry configured to: acquire a first resonance frequency distribution of a first tissue and a second resonance frequency distribution of a second tissue which is different from the first tissue; calculate a center frequency of a frequency-selective prepulse that suppresses or emphasizes either one of the first tissue and the second tissue in accordance with the first and second resonance frequency distributions; and apply the frequency-selective prepulse at the calculated center frequency and thereafter apply an RF pulse to collect a magnetic resonance signal. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein the processing circuitry acquires the first and second resonance frequency distributions with the use of a three-point Dixon method. ### Claim 3 (depends on 1) The apparatus according to claim 1, wherein the processing circuitry acquires the first and second resonance frequency distributions based on a magnitude image that is obtained by static magnetic field shimming. ### Claim 4 (depends on 1) The apparatus according to claim 1, wherein the frequency-selective prepulse is a prepulse for fat suppression. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein the frequency-selective prepulse is a prepulse for water excitation. ### Claim 6 (depends on 1) The apparatus according to claim 1, wherein the processing circuitry is further configured to display the first and second resonance frequency distributions, a frequency characteristic of the frequency-selective prepulse, and an estimated result of fat suppression. ### Claim 7 (depends on 1) The apparatus according to claim 1, wherein the processing circuitry optimizes a center frequency based on a target region in an imaging range. ### Claim 8 (depends on 1) The apparatus according to claim 1, wherein the processing circuitry calculates the center frequency in accordance with a type of the frequency-selective pulse and each of the acquired first and second resonance frequency distributions. ### Claim 9 A magnetic resonance imaging method comprising: acquiring a first resonance frequency distribution of a first tissue and a second resonance frequency distribution of a second tissue which is different from the first tissue; calculating a center frequency of a frequency-selective prepulse that suppresses or emphasizes either one of the first tissue and the second tissue in accordance with the first and second resonance frequency distributions; and applying the frequency-selective prepulse at the calculated center frequency and thereafter applying an RF pulse to collect a magnetic resonance signal. ### Claim 10 (depends on 9) The method according to claim 9, wherein the first and second resonance frequency distributions are acquired with the use of a three-point Dixon method. ### Claim 11 (depends on 9) The method according to claim 9, wherein the first and second resonance frequency distributions are acquired based on a magnitude image that is obtained by static magnetic field shimming. ### Claim 12 (depends on 9) The method according to claim 9, wherein the frequency-selective prepulse is a prepulse for fat suppression. ### Claim 13 (depends on 9) The method according to claim 9, wherein the frequency-selective prepulse is a prepulse for water excitation. ### Claim 14 (depends on 9) The method according to claim 9, further comprising displaying the first and second resonance frequency distributions, a frequency characteristic of the frequency-selective prepulse, and an estimated result of fat suppression. ### Claim 15 (depends on 9) The method according to claim 9, further comprising optimizing a center frequency based on a target region in an imaging range. ### Claim 16 (depends on 9) The method according to claim 9, wherein the center frequency is calculated in accordance with a type of the frequency-selective pulse and each of the acquired first and second resonance frequency distributions.