# US 2014/0152307 A1 · Method and apparatus for acquiring b1 magnetic field information > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152307 A1 - Document ID: US20140152307A1 - Status: Published application - Kind: A1 - Application number: 14/096,317 - Filed: 2013-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Industry Academic Cooperation Foundation Kyunghee University; Samsung Electronics Co., Ltd. - Applicants: Industry Academic Cooperation Foundation Kyunghee University; Samsung Electronics Co., Ltd. - Inventors: Ju-hyung LEE; Soo-yeol LEE - Web page: https://patentgrep.com/patent/US20140152307A1 ## CPC - G01R 33/5659: {caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field (G01R33/56509, G01R33/56518, G01R33/56536 take precedence)} - G01R 33/246: {Spatial mapping of the RF magnetic field B1} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A system acquires RF magnetic field information (B1 magnetic field information) in response to generated radio frequency (RF) pulses applied to a target object via at least one of a plurality of RF coil elements in a magnetic resonance imaging (MRI) system. The system acquires first information comprising B1 magnetic field phase information of a B1 magnetic field formed by the respective RF coil elements and acquires second information comprising B1 magnetic field phase information of a B1 magnetic field formed by a combination of two or more of a plurality of RF coil elements. The system acquires third information comprising B1 magnetic field phase information by combining the first information and the second information and processes the first, second and third information in providing a B1 map indicating spatial distribution of a B1 magnetic field. ## Claims ### Claim 1 A method of acquiring RF magnetic field information (B1 magnetic field information) in response to generated radio frequency (RF) pulses applied to a target object via at least one of a plurality of RF coil elements in a magnetic resonance imaging (MRI) system, the method comprising: acquiring first information comprising B1 magnetic field phase information of a B1 magnetic field formed by the respective RF coil elements; acquiring second information comprising B1 magnetic field phase information of a B1 magnetic field formed by a combination of two or more of a plurality of RF coil elements; and acquiring third information comprising B1 magnetic field phase information by combining the first information and the second information. ### Claim 2 (depends on 1) The method of claim 1, wherein the acquiring of the third information comprises acquiring phase information of transmission RF magnetic fields (B1+ magnetic fields) as the third information by eliminating phase information of a reception RF magnetic field (B1− magnetic field) from the first information by using the second information. ### Claim 3 (depends on 2) The method of claim 2, wherein the B1+ magnetic fields comprise magnetic field elements which rotate in a same direction as a direction in which a magnetization vector of at least one atomic nucleus, which is magnetized by a main magnetic field of the MRI system and is included in a target object, rotates. ### Claim 4 (depends on 3) The method of claim 3, further comprising acquiring the phase information of the B1− magnetic field by combining the first information and the second information, wherein the B1− magnetic field comprises a magnetic field element which rotates in a direction opposite to the direction in which the B1+ magnetic field rotates. ### Claim 5 (depends on 1) The method of claim 1, wherein the acquiring of the first information formed by the respective RF coil elements comprises: for individual coils of the plurality of RF coil elements, selecting one of the plurality of RF coil elements; applying the RF pulses to the target object via the selected RF coil element; and acquiring the first information using echo response signals received from the target object. ### Claim 6 (depends on 1) The method of claim 1, wherein the first information comprises phase information of a B1+ magnetic field formed by the respective RF coil elements and phase information of a B1− magnetic field. ### Claim 7 (depends on 1) The method of claim 1, wherein the acquiring of the second information comprises: applying the RF pulses to the target object concurrently via the combination of two or more of the plurality of RF coil elements; and acquiring the second information based on echo response signals received from the target object. ### Claim 8 (depends on 1) The method of claim 1, wherein the acquiring of the second information comprises acquiring the second information by concurrently driving the plurality of RF coil elements. ### Claim 9 (depends on 1) The method of claim 1, wherein the second information comprises phase information of a B1+ magnetic field formed by the combination of two or more of the plurality of RF coil elements and phase information of a B1− magnetic field. ### Claim 10 (depends on 1) The method of claim 1, wherein the MRI system is an MRI system using a high magnetic field equal to 3 Tesla (T) or higher. ### Claim 11 A B1 information acquiring apparatus in an MRI system including at least one of a plurality of radio frequency (RF) coil elements for acquiring B1 magnetic field information in response to RF pulses applied to a target object, the B1 information acquiring apparatus comprising a control unit, which controls a plurality of RF coil elements, the control unit comprising: a first information acquiring unit for acquiring first information comprising B1 magnetic field phase information of a B1 magnetic field formed by the respective RF coil elements; a second information acquiring unit acquiring second information comprising B1 magnetic field phase information of a B1 magnetic field formed by a combination of two or more of a plurality of RF coil elements; and a third information acquiring unit for acquiring third information comprising B1 magnetic field phase information by combining the first information and the second information. ### Claim 12 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the control unit acquires phase information of transmission RF magnetic fields (B1+ magnetic fields) as the third information by eliminating phase information of a reception RF magnetic field (B1− magnetic field) from the first information by using the second information. ### Claim 13 (depends on 12) The B1 information acquiring apparatus of claim 12, wherein the B1+ magnetic fields comprise magnetic field elements which rotate in a same direction as a direction in which a magnetization vector of at least one atomic nucleus, which is magnetized by a main magnetic field of the MRI system and is included in a target object, rotates. ### Claim 14 (depends on 13) The B1 information acquiring apparatus of claim 13, wherein the control unit further comprises a B1− information acquiring unit, which acquires the phase information of the B1− magnetic field by combining the first information and the second information, and the B1− magnetic field comprises a magnetic field element rotating in a direction opposite to the direction in which the B1+ magnetic fields rotate. ### Claim 15 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the first information acquiring unit is configured to: for individual coils of the plurality of RF coil elements, select one of the plurality of RF coil elements; apply the RF pulses to the target object via the selected RF coil element; receive echo response signals from the target object; and acquire the first information based on the echo response signals received from the target object. ### Claim 16 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the first information comprises phase information of a B1+ magnetic field formed by the respective RF coil elements and phase information of a B1− magnetic field. ### Claim 17 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the second information acquiring unit is configured to: apply the RF pulses to the target object concurrently using the combination of two or more of the plurality of RF coil elements and receive echo response signals from the target object, and acquire the second information using the echo response signals. ### Claim 18 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the second information acquiring unit acquires the second information by concurrently driving the plurality of RF coil elements. ### Claim 19 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the second information comprises phase information of a B1+ magnetic field formed by the combination of two or more of the plurality of RF coil elements and phase information of a B1− magnetic field. ### Claim 20 (depends on 11) The B1 information acquiring apparatus of claim 11, wherein the MRI system is an MRI system using a high magnetic field equal to 3 Tesla (T) or higher. ### Claim 21 (depends on 1) A computer readable recording medium having recorded thereon a computer program for implementing the method of claim 1.