Method for ascertaining an absolute scan region on a patient

Abstract

In a method and imaging device for ascertaining an absolute scan region on a patient, who is positioned on an examination table, for a subsequent medical imaging examination by operation of the medical imaging device, the height of the patient is ascertained, a relative examination region is ascertained, and the absolute scan region of the patient for the subsequent medical imaging examination is determined in a processor using the patient height and the relative examination region.

Claims

1. A method for acquiring magnetic resonance (MR) data from a patient, comprising: providing an examination table of an MR data acquisition scanner with a marking on the examination table at a spacing A from an edge of the examination table, said examination table being movable in a longitudinal direction of said MR scanner; placing a patient on the examination table at a patient position Ref relative to said marker on said examination table; providing a control computer with an electronic input that designates a height H of the patient and with another electronic input that designates a section of the patient, said section of the patient being selected from the group consisting of a defined examination region of the patient and a defined organ of the patient; in said control computer, accessing a database, after placing the patient at said patient position on said examination table, that correlates said section with said patient of said height H and, dependent on said correlation, calculating, as a range or percentage of said height H of said patient, a relative examination region that encompasses said section within said patient, said relative examination region having a start SW_Rel and an end EW_Rel in said longitudinal direction and a relative examination region length between said start and said end that is said range or percentage of said height H of said patient; in said control computer, determining a final examination region in said scanner, from which MR image data will be acquired, said final examination region having a final examination region start SW.sub.Abs at which acquisition of said medical image data by said scanner begins, and a final examination region end EW.sub.Abs at which said acquisition of said medical image data by said scanner ceases, said final examination region and being at a length L.sub.Abs from said final examination region start SW.sub.Abs, according to: ${\mathrm{SW}}_{\mathrm{Abs}}=-1\left(H-H\frac{{\mathrm{EW}}_{\mathrm{Rel}}}{100}-\left(\mathrm{Ref}-A\right)\right),\mathrm{and}$ $L_{\mathrm{Abs}}=-H\frac{\mathrm{EW\_Rel}-\mathrm{SW\_Rel}}{100};$  and with said control computer, operating said MR scanner to acquire said MR image data from said final examination region, and making the acquired MR data available in electronic form as an output from said control computer.

2. A magnetic resonance (MR) imaging apparatus comprising: an MR data acquisition; an examination table movable in a longitudinal direction into and out of said MR scanner, said examination table having a marker therein at a spacing A from an edge of the examination table, and being adapted to receive a patient thereon at a patient position Ref relative to said marker on said examination table; a control computer configured to operate said scanner in order to acquire MR image data from said patient; said control computer being configured to receive an electronic input that designates a height H of the patient and another electronic input that designates a section of the patient, said section of the patient being selected from the group consisting of a defined examination region of the patient and a defined organ of the patient; after placing the patient at said patient position on said examination table, said control computer being configured to access a database that correlates said section with said height of said patient and, dependent on said correlation, to calculate, as a range or percentage of said height of said patient, a relative examination region that encompasses said section within said patient, said relative examination region having a start SW_Rel and an end EW_Rel in said longitudinal direction and a relative examination region length between said start and said end that is said range or percentage of said height H of said patient; said control computer being configured to determine a final examination region in said scanner, from which said MR image data will be acquired, along said longitudinal direction, said final examination region having a final examination region start SW.sub.Abs at which acquisition of said medical image data by said scanner begins, and a final examination region end EW.sub.Abs at which said acquisition of said medical image data by said scanner ceases said final examination region and being at a length L.sub.Abs from said final examination region start SW.sub.Abs, according to: ${\mathrm{SW}}_{\mathrm{Abs}}=-1\left(H-H\frac{{\mathrm{EW}}_{\mathrm{Rel}}}{100}-\left(\mathrm{Ref}-A\right)\right),\mathrm{and}$ $L_{\mathrm{Abs}}=-H\frac{\mathrm{EW\_Rel}-\mathrm{SW\_Rel}}{100};$  and said control computer being configured to operate said MR scanner to acquire said MR image data from said final examination region, and to make the acquired MR data available in electronic form as an output from said control computer.

3. A non-transitory, computer-readable data storage medium encoded with programming instructions, said storage medium being loaded into a control computer of a magnetic resonance MR apparatus that comprises an MR data acquisition scanner and an examination table movable in a longitudinal direction into and out of said MR scanner, said examination table having a marker therein at a spacing A from an edge of the examination table, and being adapted to receive a patient thereon at a patient position Ref relative to said marker on said examination table, said programming instructions causing said control computer to: receive an electronic input that designates a height H of the patient and another electronic input that designates a section of the patient, said section of the patient being selected from the group consisting of a defined examination region of the patient and a defined organ of the patient; after placing the patient at said patient position on said examination table, access a database that correlates said section with said height of the patient and, dependent on said correlation, calculating, as a range or percentage of said height of said patient, a relative examination region that encompasses said section within said patient, said relative examination region having a start SW_Rel and an end EW_Rel in said longitudinal direction and a relative examination region length between said start and said end that is said range or percentage of said height H of said patient; determine a final examination region in said scanner, from which said MR image data will be acquired along said longitudinal direction, said final examination region having a final examination region start SW.sub.Abs at which acquisition of said medical image data by said scanner begins, and a final examination region end EW.sub.Abs at which said acquisition of said medical image data by said scanner ceases, said final examination region and being at a length L.sub.Abs from said final examination region start SW.sub.Abs, according to: ${\mathrm{SW}}_{\mathrm{Abs}}=-1\left(H-H\frac{{\mathrm{EW}}_{\mathrm{Rel}}}{100}-\left(\mathrm{Ref}-A\right)\right),\mathrm{and}$ $L_{\mathrm{Abs}}=-H\frac{\mathrm{EW\_Rel}-\mathrm{SW\_Rel}}{100};$  and operate said MR scanner to acquire said MR image data from said final examination region, and make the acquired MR data available in electronic form as an output from said control computer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically illustrates an inventive medical imaging apparatus in a schematic view.

(2) FIG. 2 is a flowchart of the inventive method for ascertaining an absolute scan region on a patient.

(3) FIG. 3 illustrates a determination of an absolute scan region on a first patient in a schematic view.

(4) FIG. 4 illustrates a determination of an absolute scan region on a second patient in a schematic view.

(5) FIG. 5 is a schematic view of a relative examination region on a patient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) FIG. 1 schematically shows a medical imaging device. In the present exemplary embodiment the medical imaging device is formed by a magnetic resonance apparatus 10. The embodiment of the medical imaging device is not limited to a magnetic resonance apparatus 10, however. Instead the medical imaging apparatus can be formed by any medical imaging apparatus that seems expedient to those skilled in the art, such as by a computed tomography apparatus, a positron-emission tomography apparatus, etc.

(7) The magnetic resonance apparatus 10 has a magnet unit 11 that includes a super-conducting basic field magnet 12 for generating a strong and constant main basic magnetic field 13. Furthermore, the magnetic resonance apparatus 10 has a patient-receiving region 14 for receiving a patient 15. The patient-receiving region 14 in the present exemplary embodiment is cylindrical and cylindrically surrounded in a circumferential direction by the magnetic unit 11. Basically, however, a design of the patient-receiving region 14 that is different is conceivable. The patient 15 can be moved by a patient positioning device 16 of the magnetic resonance apparatus 10 into the patient-receiving region 14. The patient positioning device 16 has for this purpose an examination table 17 designed to be moved inside the patient-receiving region 14.

(8) The magnet unit 11 also has a gradient coil unit 18 for generating magnetic field gradients which are used for spatial encoding during imaging. The gradient coil unit 18 is controlled by means of a gradient control computer 19 of the magnetic resonance apparatus 10. The magnetic unit 11 also has a radio-frequency antenna unit 20 for exciting a polarization that is established in the main magnetic field 13 generated by the basic field magnet 12. The radio-frequency antenna unit 20 is controlled by a radio-frequency (RF) antenna control unit 21 of the magnetic resonance apparatus 10 and emits radio-frequency magnetic resonance sequences into an examination space, which is substantially formed by a patient-receiving region 14 of the magnetic resonance apparatus 10.

(9) To control the basic field magnet 12, the gradient control unit 19 and to control the radio-frequency antenna control unit 21, the magnetic resonance apparatus 10 has a system control computer 22. The system control computer 22 centrally controls the magnetic resonance apparatus 10, such as for the performance of a pre-determined imaging gradient echo sequence. Furthermore, the system control unit 22 has an evaluation unit (not shown) for evaluating medical image data that are acquired during the magnetic resonance examination. The magnetic resonance apparatus 10 also has a user interface 23 that is connected to the system control computer 22. Control information such as imaging parameters and reconstructed magnetic resonance images can be displayed for medical operating personnel on a display unit 24, for example on at least one monitor, of the user interface 23. The user interface 23 also has an input unit 25, via which information and/or parameters can be entered by the medical operating personnel during a measuring process.

(10) Before a magnetic resonance examination can be carried out on the patient 15, the patient 15 must firstly be positioned on the examination table 17. In addition, an absolute scan region R_Abs of the patient 15 must be ascertained for the pending magnetic resonance examination. This absolute scan region R_Abs ascertains a region of the patient 15 from which medical image data are to be acquired by magnetic resonance scans of the pending magnetic resonance examination.

(11) FIG. 2 shows a flowchart of an inventive method for ascertaining an absolute scan region R_Abs on a patient 15, who is positioned on the examination table 17, for a subsequent medical imaging examination, in the present exemplary embodiment for a magnetic resonance examination. The method is performed by the system control computer 22 of the magnetic resonance apparatus 10, with the system control computer 22 having a memory unit 26 and an arithmetic unit 27 with a processor unit (not shown) for this purpose. Furthermore, the system control computer 22 has evaluation software and/or evaluation computer programs that are required for this and are stored in the memory unit 26 and are executed for a progression of the method for ascertaining an absolute scan region on the patient 15 by the processor unit of the arithmetic unit 27.

(12) For this purpose, a height H of the patient is firstly ascertained in a first method step 100. The patient height H can be provided manually by medical operating personnel via the input unit 25 of the magnetic resonance apparatus 10, in particular the system control computer 22. Furthermore, ascertainment of the patient height H may also include calling up and/or loading of a stored patient data record, in which the patient height H is stored. The patient height H preferably includes the body size of the patient 15.

(13) In a further method step 101 a relative examination region R_Rel of the patient 15 is ascertained. The relative examination region R_Rel can likewise be ascertained manually by the medical operating personnel via the input unit 25. The relative examination region R_Rel can be ascertained by the medical operating personnel in relation to the patient height H, in particular input, such as in the form of a percentage value of the relative examination region R_Rel in relation to the height H of the patient 15. For example, the relative examination region R_Rel for an examination of the liver on the patient 15 can be a region between 53% and 73% of the patient height H.

(14) The relative examination region R_Rel can also be ascertained by the medical operating personnel by means of an input of a relative start value SW_Rel of the relative examination region R_Rel and/or by means of an input of a relative end value EW_Rel of the relative examination region R_Rel. The relative start value SW_Rel and/or the relative end value EW_Rel of the relative examination region R_Rel are preferably in relation to the height H of the patient 15. Alternatively or additionally, the relative start value SW_Rel and/or the relative end value EW_Rel of the relative examination region R_Rel can also be ascertained in relation to a reference point, such as in relation to an edge and/or an edge region of the examination table 17 etc., as is also shown in FIG. 5.

(15) Using the relative start value SW_Rel and the relative end value EW_Rel a length L_Rel of the relative examination region R_Rel can be determined which matches a length L_Abs of the absolute scan region R_Abs. In addition, the length L_Rel of the relative examination region R_Rel together with the relative start value SW_Rel or the relative end value EW_Rel can be ascertained by the medical operating personnel.

(16) It is also conceivable, moreover, for medical operating personnel to only ascertain a section that is to be examined of the patient 15 in this method step 101, in particular to ascertain this section on an organ, such as on a region of the liver and/or heart, of the patient 15. This section can include a defined examination region and/or a defined organ of the patient 15. The choice of relative examination region R_Rel can then be made automatically by means of the arithmetic unit 27 of the system control computer 22 using the ascertained section that is to be examined. This defined examination region of the patient 15 can be ascertained by the medical operating personnel as a percentage value of this region, in particular in relation to the height H of the patient. These percentages can be read by way of example from a table, since, in relation to the patient height H, the relative examination region R_Rel in the form of a percentage share and/or a percentage range remains the same in each case, as can be seen in FIGS. 3 and 4. FIGS. 3 and 4 show the relative examination region R_Rel for two patients 15 of different heights. Due to the different heights H of the patients 15 in FIGS. 3 and 4 a percentage value of the relative examination region R_Rel in relation to the patient height H remains the same but the absolute scan region R_Abs of the respective patient 15 that results therefrom varies.

(17) Furthermore it is also conceivable for just the disclosure and/or ascertainment of a defined examination region and/or body region of the patient 15 to be made by medical operating personnel, and the arithmetic unit 27 automatically ascertains start values and/or end values of the relative examination region R_Rel using this disclosure. For this purpose, the arithmetic unit 27 preferably uses examination data and/or allocations of organ regions to a human body stored and/or saved inside the memory unit 26.

(18) If the relative examination region R_Rel is automatically ascertained by the arithmetic unit 27 by retrieving pre-defined values and/or stored data, it may also be provided that this stored data also already includes a predefined position of the patient 15. This data can be, for example, an orientation and/or position of the patient 15 relative to the examination table 17. For examinations of the head by way of example, the patient 15 is positioned on the examination table 17 head first. Furthermore, even when using a local head coil a position of the patient 15 is ascertained on the basis of a predefined position of the local head coil on the examination table 17.

(19) If this information does not yet exist, it must be ascertained by medical operating personnel in a further method step 102 before the absolute scan region R_Abs of the patient 15 is calculated by means of the user interface 23. For this purpose the medical operating personnel must ascertain an orientation of the patient 15 in relation to the examination table 17, whether he/she is positioned feet and/or head first on the examination table 17. Furthermore, a spacing A of the patient 15 from an edge region of the examination table 17 is also ascertained in this method step 102, with the spacing A having already been predetermined. The spacing A of the patient 15 from the edge region of the examination table 17 is predefined by markings in particular. The examination table 17 can therefore include cushions, for example, for positioning the patient 15, with these cushions having markings for positioning a head and/or for positioning the feet of the patient 15. These markings have an exactly defined position in relation to the patient positioning device 16, in particular the examination table 17.

(20) Using the acquired patient height H and the relative examination region R_Rel the absolute scan region R_Abs is calculated by the arithmetic unit 27 in a further method step 103. A length L_Abs of the absolute scan region R_Abs and an absolute start value SW_Abs of the absolute scan region R_Abs is determined by the arithmetic unit 27.

(21) The absolute start value SW_Abs is calculated as follows by the arithmetic unit 27:

(22) ${\mathrm{SW}}_{\mathrm{Abs}}=-1(H-H\frac{\mathrm{EW\_Rel}}{100}-\left(\mathrm{Ref}-A\right).$

(23) The absolute length L_Abs of the absolute scan region R_Abs is determined as follows:

(24) $L_{\mathrm{Abs}}=-H\frac{\mathrm{EW\_Rel}-\mathrm{SW\_Rel}}{100}.$

(25) Here Ref is the reference position, in relation to which the absolute scan region (R_Abs), in particular the absolute start value SW_Abs and the absolute length L_Abs of the absolute scan region R_Abs, is determined. In the present exemplary embodiment (FIG. 5) the reference position is ascertained at the center of the head of the patient 15. Basically any other ascertainment of the reference position that seems expedient to those skilled in the art is always possible, however.

(26) Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art.