JP2016019586A - Freezing treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing treatment system, in which temperature distribution of inside of a freeze area during freezing treatment, or the freeze area whose temperature is equal to or less than freezing temperature required for necrosis, can be imaged into MR images.SOLUTION: A freezing treatment system comprises: a magnetic resonance imaging device 1 for imaging an MR image of a living body including a lesioned part which is treated by freezing treatment by a freezing probe 36 which is punctured to the lesioned part of the living body; and display parts 13 and 38 for displaying the MR image. The magnetic resonance imaging device 1 repeats an imaging sequence of echo time TE capable of drawing a contrast of the MR image of inside of the freezing area which is frozen by the freezing probe 36, images the MR images in time series from the start of treatment by the freezing probe 36, and displays a temperature distribution image of inside of the freezing area of the lesioned part on the display parts 13 and 38.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cryotherapy system, and more particularly, to a technique for visualizing a temperature distribution inside a frozen area (Ice-ball) of a lesion part of a living body to be cryotreated or a region below a specified temperature.

  A cryotherapy apparatus that freezes and kills a lesioned part with a cryoprobe punctured in a living part of a living body and treats it is known from Patent Document 1 and the like. A cryotherapy system equipped with such a cryotherapy apparatus can, for example, continuously image an image of a lesion using an MRI apparatus, which is one of medical imaging apparatuses, and determine the progress of cryotherapy based on the captured image. It is configured. For example, according to Patent Document 1, a difference image between a pre-treatment image of a lesioned part and an image during treatment that is continuously imaged is obtained by an MRI apparatus, and a distance between a treatment region outer edge and a lesioned part outer edge is calculated from the difference image. Then, the point in time when the distance becomes a predetermined value is determined as the end point of the treatment and is notified to the user.

Japanese Patent No. 4514438

  In general, in cryotherapy, a lesion such as a malignant tumor is frozen (for example, −20 ° C. or lower) to be necrotic. However, even if it is attempted to observe the progress of cryotherapy with MR images, it is difficult to image a frozen region with an appropriate image contrast (luminance contrast) with a normal MRI apparatus. That is, in the MRI apparatus, the intensity of the NMR signal of protons extremely decreases at a low temperature of 0 ° C. or lower. Therefore, in a normal MR image, the brightness contrast of the frozen region decreases and the temperature difference cannot be recognized. That is, the freezing area (ice ball) has an outer periphery of 0 ° C., and is frozen to an extremely low temperature toward the inside. However, since the image contrast is lowered, the freezing area below the specified temperature of necrosis (for example, −20 ° C.) Cannot be recognized by MR image. Therefore, in the differential imaging method described in Patent Document 1, since no consideration is given to an objective index that can be judged as the end of treatment by how much the frozen region covers the lesioned part, cryotherapy is performed depending on the experience and intuition of the doctor. This is the current situation.

  The problem to be solved by the present invention is to provide a cryotherapy system capable of MR imaging the temperature distribution inside the frozen area during cryotherapy or the frozen area below the freezing temperature necessary for necrosis.

  In order to solve the above-described problem, the cryotherapy system of the present invention includes an imaging unit that captures an MR image of the living body including the lesioned part that is cryotreated by a cryoprobe punctured into the lesioned part of the living body, and the MR An imaging sequence having an echo time that can depict the contrast of the MR image inside the frozen region frozen by the freezing probe. Repeatedly, the MR image in time series from the start of treatment with the cryoprobe is picked up, and the temperature distribution image inside the frozen region of the lesioned part is displayed on the display unit.

  That is, in an imaging sequence having an echo time (TE) of several milliseconds or more used in normal MRI imaging (hereinafter referred to as a normal TE sequence in the present specification), the boundary of a cryotherapy area (ice ball) and Since the T1 value that is the longitudinal relaxation time is short inside, an MR image with sufficient luminance contrast cannot be obtained. On the other hand, according to an imaging sequence having an echo time of less than 1 millisecond (hereinafter referred to as an ultra-short TE sequence or a micro TE sequence in the present specification), luminance contrast can be obtained even in a frozen region with a short T1 value. . For example, in an ultra-short TE sequence in which TE is shortened to several hundred microseconds, brightness contrast appears moderately even at the boundary and inside of an ice ball. Since the luminance contrast depends on the characteristics of protons according to temperature, the temperature distribution inside the frozen region can be identified.

  In other words, if an imaging sequence of echo time that can depict the brightness contrast of the MR image inside the frozen region is used, the temperature distribution inside the frozen region during the cryotherapy can be visualized. However, the imaging sequence of the present invention is not limited to the ultra-short TE sequence or the micro TE sequence. If a constant brightness contrast is obtained even in a frozen region with a short T1 value, the temperature distribution inside the frozen region is constant. Can be identified in the range.

  Furthermore, the image signal of the time-series MR image captured by an imaging sequence of echo time that can depict the brightness contrast of the MR image inside the frozen region is acquired, and the intensity of the image signal is determined by scanning the MR image. A freezing region analysis unit for discriminating a predetermined freezing region below a predetermined specified temperature for each MR image in time series based on a freezing feature pattern in which a peak appears at the boundary between the frozen region and the unfrozen region of the lesioned part The freezing region analysis unit can generate an image showing the prescribed freezing region and display the image on the time-series MR image on the display unit. According to this, since a frozen region below a predetermined temperature (for example, −20 ° C.) that is predetermined as a freezing temperature at which the lesion part is necrosed can be visualized by an image, the determination of the end of treatment is not based on the experience of the doctor and intuition. Can be done objectively.

  ADVANTAGE OF THE INVENTION According to this invention, the cryotherapy system which can visualize the area | region frozen below the freezing temperature required for the temperature distribution inside a frozen area at the time of cryotherapy or necrosis can be provided.

1 is an overall configuration diagram of a cryotherapy system according to an embodiment of the present invention. It is a figure explaining the navigation guide display function of the cryotherapy system of one embodiment of the present invention. It is a figure which shows the structure of the principal part of the cryotherapy apparatus of one Embodiment of this invention. It is a figure which shows the time change of the freezing area | region by the freezing probe of one Embodiment. It is a flowchart of one Embodiment of the cryotherapy procedure using the cryotherapy system of this invention. It is a flowchart which shows the detailed procedure in step S111 of the flowchart of FIG. It is a figure which shows one Embodiment of the imaging sequence of MRI for monitoring the inside of an ice ball. It is a figure which shows the time-sequential normal TE image and micro TE image which are obtained by repeatedly performing the imaging sequence of FIG. It is a figure explaining the freezing area | region analysis part which is the other characteristics of one Embodiment of this invention. It is a figure which shows the example of a display of the graphic user interface (GUI) at the time of the cryotherapy by this invention.

  Hereinafter, the present invention will be described based on embodiments.

  FIG. 1 shows an overall configuration of a cryotherapy system according to an embodiment of the present invention. As shown in the figure, the MRI apparatus 1 constituting the cryotherapy system is, for example, a vertical magnetic field type permanent magnet MRI apparatus, which connects an upper magnet 3 and a lower magnet 5 that generate a vertical static magnetic field, and connects these magnets. It includes a column 7 that supports the upper magnet 3, a position detection device 9, an arm 11, monitors 13, 14, a monitor support unit 15, a reference tool 17, a personal computer 19, a bed 21, an MR control unit 23, and the like. .

  A gradient magnetic field generation unit (not shown) of the MRI apparatus 1 generates the oblique magnetic field in pulses. Further, the MRI apparatus 1 includes an RF transmitter (not shown) for generating nuclear magnetic resonance in the patient 24 in a static magnetic field and an RF receiver (not shown) for receiving a nuclear magnetic resonance signal from the patient 24.

  The position detection device 9 includes two infrared cameras 25 and a light emitting diode (not shown) that emits infrared rays, and detects the position and posture of a pointer 27 that is a tomographic plane indicating device. The position detection device 9 is connected to the upper magnet 3 so as to be movable by an arm 11 and appropriately changes the arrangement relative to the MRI apparatus 1. The monitor 13 displays an MR image of the tomographic plane of the patient 24 indicated by the pointer 27 held by the operator 29, and is connected to the upper magnet 3 by the monitor support unit 15 similarly to the infrared camera 25. . The reference tool 17 links the coordinate system of the infrared camera 25 and the coordinate system of the MRI apparatus 1, includes three reflecting spheres 35, and is provided on the side surface of the upper magnet 3.

  Information of the pointer 27 detected and calculated by the infrared camera 25 is transmitted to the personal computer 19 as position data of the freezing probe 36 via, for example, the RS232C cable 33. Here, the position or position data of the freezing probe 36 includes the inclination or inclination data of the freezing probe 36. Hereinafter, the position or position data will be simply referred to as position or position data. The MR control unit 23 is composed of a workstation and controls an RF transmitter, an RF receiver, etc. (not shown). The MR control unit 23 is connected to the personal computer 19. In the personal computer 19, the position of the pointer 27 detected and calculated by the infrared camera 25 is converted into position data of the imaging range of the MRI apparatus 1 and transmitted to the MR control unit 23. The position data is reflected on the imaging section of the imaging sequence. The MR image acquired with the new imaging section is displayed on the monitor 13. MR images are simultaneously recorded in the video recording device 34. For example, when the pointer 27 which is a tomographic plane indicating device is attached to the frozen probe 36 and configured so that the position at which the frozen probe 36 is always taken as the imaging section, the section including the frozen probe 36 is always displayed on the monitor 13. become.

  In addition, a cryotherapy apparatus 40 is connected to the personal computer 19. A cryoprobe 36 is connected to the cryotherapy apparatus 40 via a freezing gas wiring. As a result, frozen gas is filled in the freezing probe 36 simultaneously with the start of treatment, and a treatment start signal is transmitted to the personal computer 19, so that synchronous imaging of MR images is started simultaneously with the treatment. However, MR image capturing conditions are registered in advance. During the cryotherapy, the treatment information and the cryo equipment status are displayed on the cryotherapy apparatus monitor 38, and the treatment is performed according to a preset treatment protocol.

  The navigation guide display function will be described with reference to FIG. The operator 29 approaches the treatment target (target), which is a lesion, using the cryoprobe 36 with respect to the patient 24. The MR image information is displayed on the monitor 13. Here, a pointer 27 for detecting the position is attached to the freezing probe 36, and the position detection device 9 is used to follow the position of the target. The position of the frozen probe 36 is detected from the position of the pointer 27 by the infrared camera 25 attached to the position detection device 9 and displayed on the navigation images 313 to 316, respectively. The screen 13 of the monitor 13 can freely select a volume rendering image 316 in addition to the navigation images 313 to 315 having three-axis cross sections (Axial, Sagittal, and Coronal). The surgeon 29 sets the scheduled treatment area 320, the warning area, and the margin area 321 before the treatment.

  On the navigation image, in addition to the simulated image 317 of the frozen probe 36, a simulated image 322 of the frozen probe 36 by pre-treatment planning (treatment simulation) can also be displayed superimposed on the image. In addition, the treatment rendering area 320 corresponding to the frozen probe 36 can be displayed in a three-dimensional manner on the volume rendering image etc. 316. Further, it has a function of issuing a warning when the frozen probe 36 enters the treatment scheduled area 320 or the warning area 321 on the navigation image 313-316. In addition, the above conditions can be changed according to the treatment environment. For example, it has a function of automatically changing a navigation image and a treatment parameter when the treatment scheduled region 320 enters the warning region 321. By feeding back this information to the MRI apparatus 1 continuously and in real time, an MR image 304 including the frozen probe 36 in the treatment planned area can be obtained. That is, the surgeon can apply the two-dimensional real-time image based on the MR image and the three-dimensional image information based on the navigation as necessary.

  As one application of the high-speed imaging sequence of the MRI apparatus 1, a real-time dynamic imaging method called fluoroscopy (perspective imaging) is being clinically applied. In fluoroscopy, by repeating imaging and image reconstruction with a period of about 1 second or less, it can be used to extract the dynamics of internal tissues and to grasp the position of an instrument inserted from the outside like a fluoroscopic imaging. Generate and display dynamic images. This application is also applied to three-dimensional high-speed imaging.

  In FIG. 3, the structure of the principal part of the cryotherapy apparatus 40 of one Embodiment of this invention is shown. The cryotherapy apparatus 40 mainly includes a freezing control unit 41 and a freezing probe 36. The cryotherapy apparatus 40 utilizes the “Joule-Thomsos effect” and is an MR-compatible cryotherapy device capable of freezing and thawing. In this embodiment, the argon gas Ar is filled in the gas cylinder 403 as a freezing gas, and the helium gas Hr is filled in the gas cylinder 404 as a thawing gas. The gas cylinders 403 and 404 are connected to the freezing probe 36 through the valves 408 and 409, respectively, and the freezing gas (for example, argon gas Ar) supplied to the freezing probe 36 and thawing are controlled by opening control of the valves 408 and 409. A gas (for example, helium gas Hr) is controlled.

  The cryoprobe 36 is formed in a two-cavity structure. In other words, a thin tube 36b is disposed at the center of the needle-shaped outer shell 36a, and a nozzle 36c having an opening at the tip of the thin tube 36b is formed at the tip of the needle-shaped outer shell 36a. Further, a heat exchanger portion 36d is formed in a part of the narrow tube 36b disposed in the needle-shaped outer shell 36a. The proximal end of the needle-shaped outer shell 36 a is connected to valves 408 and 409 of the freezing control unit 41 through a hose 42. Thus, when the valve 408 is opened and frozen gas is supplied into the narrow tube 36b of the freezing probe 36, high-pressure frozen gas is ejected from the nozzle 36c at the tip into the tip of the needle-shaped outer shell 36a.・ The frozen gas is cooled by the Thomson effect. That is, when freezing gas (argon gas Ar) having a high pressure (24 to 27 MPa) is ejected into a small chamber at the tip of the freezing probe 36 at atmospheric pressure, the tip of the freezing probe 36 has a cryogenic temperature of −185 ° C. The cryogenic freezing gas passes through the outside of the heat exchanger 36d, cools the freezing gas in the narrow tube 36b, and is discharged from the proximal end of the needle-shaped outer shell 36a through the hose 42 to the atmosphere. In this way, the lesioned part where the tip of the freezing probe 36 is punctured is frozen.

  On the other hand, when the valve 409 is opened and a high-pressure (17 to 27 MPa) thawing gas (helium gas) is supplied into the narrow tube 36 b of the freezing probe 36, the high-pressure freezing gas is ejected from the nozzle 36 c at the front end. Temperature rises. Thereby, the frozen region of the frozen lesion is thawed. Note that the actual frozen portion of the lesion is, for example, about 2 cm at the tip of the cryoprobe 36 as shown in FIG. Therefore, by increasing or decreasing the number of the frozen probes 36 according to the size of the treatment planned area 320 which is a lesion to be treated, for example, three frozen probes 36 are punctured as shown in FIG. Thus, a large freezing area (ice ball) 412 can be created. Then, when the frozen region 412 covers the lesioned part 410, the treatment ends. Reference numeral 413 in the figure is a frozen region of a lesion.

  In conjunction with the above-mentioned Joule-Thompson effect, medical cryotherapy equipment compatible with MRI has been developed using argon gas for freezing with high-pressure gas and helium gas for thawing. It is used for such treatment. Further, the temperature measurement range of the cryotherapy device is -190 ° C to + 80 ° C, and conversion of freeze-thawing is easy, and temperature changes of -165 ° C and + 54 ° C can be obtained in 10 seconds. The range in which the cryogenic temperature can be obtained is 2 cm at the probe tip, and the other parts are kept at room temperature. Also, there are probes that are MRI compatible and bent at a right angle. A medical cryotherapy device is described in a patent document (USP-5522870). Further, the frozen region can be imaged by a medical imaging apparatus such as X-ray, CT, US, MRI. In particular, the MRI apparatus is favorably used because a sharp surface line can be obtained in cryotherapy and the ability to draw ice is extremely excellent.

  FIG. 4 shows the time change of the frozen region by the freezing probe 36. FIG. 5A shows a simulated image including the tip of the freezing probe 36 before the start of freezing. The diameter of the ice ball 505 at the start of freezing expands as indicated by reference numerals 507 and 508 in FIGS. 5B to 5C as t1 seconds elapse and t2 seconds elapse from the start of treatment. In the illustrated example, the description is made in two dimensions for easy understanding. However, since an actual ice ball grows three-dimensionally, three-dimensional analysis is performed.

  FIG. 5 shows a flowchart of one embodiment of a cryotherapy procedure using the cryotherapy system of the present invention. In the present embodiment, a cryotherapy system using an MRI apparatus as a medical image apparatus will be described. A plurality of three-dimensional volume imaging and three-dimensional reconstruction of a three-dimensional image are performed using an MRI apparatus (S101), and a specific region rendering (treatment essential region: segmentation) is rendered from the three-dimensional image by image processing (S102). ). After the treatment plan is implemented (S103), necessary parameters are input to the treatment device (S104), a surgical support guidance function such as navigation is activated (S105), and treatment is started (S106).

  At the time of treatment, all the actions and image information of the surgeon are monitored, the frozen probe 36 is followed, a simulated image 317 is superimposed on the navigation image, and the frozen probe 36 is set to the target position (planned treatment area using numerical information). 320) (S107). If necessary, the target position is confirmed by MRI and ultrasonic images (blood flow image, elastography, etc.) (S108). If there is no problem with the treatment position, cryotherapy is started (S109). Simultaneously with the start of cryotherapy, frozen region (ice ball) monitoring by MR images is performed (S110. Simultaneously, signal analysis is performed in real time (S111). The detailed procedure in this step S111 is shown in FIG.

  As shown in FIG. 6, MR image capturing is performed by multi-slice using a composite imaging sequence of a micro TE sequence and a normal TE sequence. Specifically, one scanning line (line) of a micro TE image obtained by micro TE sequence imaging is selected (S121), and an image signal profile is acquired (S122). The signal intensity of the image signal profile is graphed (S123), the half-value width of the image signal profile is set (S124), and the region within the half-value width is drawn as a specified freezing line (S125). All lines of the micro TE image are analyzed (S126), the specified freezing line of the acquired half-value width area is two-dimensionally arranged (S127), and the area filled with the specified freezing line is registered and recognized as the specified freezing area ( S128).

  If necessary, the slice cross section is changed (S130), a three-dimensional distribution analysis is performed (S129), and the prescribed frozen region is registered (S131). Using the information on the specified freezing area, the specified freezing area image is superimposed and displayed on the normal MRI image captured in the normal TE sequence (S112). Next, based on the superimposed image, it is determined whether or not the lesioned part (tumor region) is within the prescribed freezing region inside the ice ball (S113). Then, if the prescribed frozen region covers the tumor region, the treatment is stopped and the treatment effect is confirmed (S114), and if there is no additional treatment, the treatment is terminated (S115).

  Hereinafter, the structure of the characteristic part of one Embodiment of the cryotherapy system of this invention is demonstrated with an operation | movement. First, the basic technique of the characteristic part of this embodiment will be described. In general, in an MRI apparatus, a nuclear magnetic resonance signal (NMR signal) is generated by exciting a nuclear spin of a living body as a subject. At that time, in order to select and excite a specific region of the living body, a slice selective gradient magnetic field is applied together with the high-frequency magnetic field pulse. As the high frequency magnetic field pulse, a high frequency modulated by an envelope such as a symmetric sinc function is usually used. The profile obtained by Fourier transforming the high-frequency magnetic field modulated by the sinc function in the frequency direction is rectangular, and a predetermined rectangular region determined by the slice gradient magnetic field is excited.

  A high-frequency magnetic field pulse having a predetermined waveform having an envelope of a symmetric function is referred to as a full RF pulse. In contrast, a half waveform of the full RF pulse, that is, a waveform of a part of the full RF pulse is referred to as a half RF pulse, and a method of MR imaging using the high frequency magnetic field pulse has been proposed (US Pat. No. 5,025,216, US). Patent No. 5150053 etc.). A half RF pulse is a pulse that uses only the waveform of the first half when, for example, a symmetric sinc pulse is divided before and after in the time direction around its peak. By applying this half RF pulse, without using a phase encode gradient magnetic field, and without using a phase gradient magnetic field as a read gradient magnetic field when measuring an echo signal, measuring a signal from the rising edge of the read gradient magnetic field, A signal can be measured with an extremely short echo time (TE) from spin excitation. This imaging method is called ultrashort TE imaging (UTE imaging). Since ultra-short TE imaging can further shorten TE in this way, it is expected to be applied to imaging of a tissue having a short longitudinal relaxation time T1, which has been difficult to image by conventional MRI.

  The echo signal obtained by excitation with the half RF pulse is measurement data from one side from the origin when the slice axis of k space is considered. For this reason, in ultra-short TE imaging, two measurements are performed with different polarities of the slice gradient magnetic field applied together with the half RF pulse, and the signals (raw data) obtained by these two measurements are complex-added. Thus, a signal equivalent to that obtained when a full RF pulse is used is obtained.

  FIG. 7 shows an embodiment of an MRI imaging sequence for monitoring the inside of an ice ball (frozen area). As illustrated, the imaging sequence of the present embodiment is a composite imaging sequence of a micro TE sequence suitable for monitoring the inside of the ice ball and a normal TE sequence. The micro TE sequence is a half RF that uses only one half of the excitation RF pulse 901, a half echo measurement that acquires one half of the echo signal 905, and an echo signal in the rising region of the readout gradient magnetic field pulse. This is characterized by non-linear measurement (903, 904). Thereby, for example, an extremely short echo time TE1 of 250 μs can be realized. Further, following the micro measurement of the echo time TE1, the phase encode gradient magnetic field 911912 and the read gradient magnetic field 913 are applied as multi-echo measurement, and the echo signal 914 of the normal TE2 is also acquired simultaneously.

  As shown in FIG. 7, the data of the echo signal 905 acquired by the micro TE sequence is arranged in the k space 907 and is imaged using a radial sampling technique for sampling in a radial manner. As a result, a micro TE MR image (hereinafter referred to as a micro TE image) 908 having an effect of reducing motion artifacts is obtained. On the other hand, the echo signal 914 of the normal TE sequence is obtained by applying the phase encoding gradient magnetic fields 911 and 912 and using the read gradient magnetic field 913, and is arranged in the k space 916 in a normal manner, and is an MR image of the normal TE. (Hereinafter referred to as a normal TE image) 917 is obtained.

  FIG. 8 shows a time-series normal TE image and micro TE image obtained by repeatedly executing the composite imaging sequence of FIG. In the figure, time elapses from left to right, (a) shows time-series normal TE images 601, 604, 607, 609, and 611, and (b) shows time-series micro TE images 602, 606, and 608. , 610, 612. The normal TE image 601 and the micro TE image 602 are T1-weighted images immediately before the start of the cryotherapy, and the normal TE image and the micro TE image are sequentially depicted in the drawing according to the elapsed time from the start of the cryotherapy. From the micro TE images 602, 606, 608, 610, and 612, it can be observed that the ice balls 631 to 634 are sequentially enlarged as illustrated. This imaging is continuously performed until the cryotherapy is completed. Here, since the MRI signal component is close to no signal, the ice ball 605 normally drawn by the TE images 604, 607, 609, and 611 is drawn black. In contrast, since the micro TE images 606, 608, 610, and 612 have an extremely short time until echo acquisition, the MRI signal component can be detected and imaged as a medium signal intensity. In the figure, the inside of the ice balls 631 to 634 inherently continuously changes in contrast, but for the convenience of illustration, it is shown in a stepwise contrast.

  By the way, it is common for cryotherapy to perform two cycles of cryotherapy for a certain period of time. That is, in the cryotherapy, two cycles of the cryotherapy cycle are performed in which the lesion is frozen and subsequently the frozen region is thawed. The point of the cryotherapy cycle is to freeze it quickly and thaw it slowly, which is said to cause the greatest tissue damage and cell damage. Further, the time for the cryotherapy cycle is generally set at 2 minutes. According to this, although the ice ball is not completely melted and a part remains, the frozen region below −40 ° C. is considered to have necrotic cells, so only the portion above −40 ° C. is frozen twice. The idea is that it should be done.

  With reference to FIG. 9, the freezing area analysis part which is the other characteristic of one Embodiment of this invention is demonstrated. The freezing area analysis unit is characterized by determining a specified freezing area below a predetermined temperature based on a time-series micro TE image. That is, the frozen region analysis unit acquires an image signal of a time-series micro TE image. Then, the micro TE image is scanned to obtain a frozen feature pattern in which the image signal intensity has a peak at the boundary between the frozen region and the unfrozen region of the lesion. Based on the freezing feature pattern, the specified freezing area is determined, and a specified freezing area image that is an image showing the specified freezing area is generated. The generated specified freezing region image is displayed superimposed on the time-series micro TE image of the monitor 13 or the cryotherapy apparatus monitor 38 as a display unit.

  FIG. 9 shows a profile of the image signal intensity for each scanning line (scanning line) for the micro TE images 606, 608, 610, and 612 obtained in FIG. 8B obtained in real time. It is a figure explaining the function of the freezing area analysis part which analyzes the profile of image signal intensity and produces | generates and displays the image of a regular freezing area. That is, FIG. 9A shows an image signal intensity profile 711 of one scanning line 700 of the micro TE image. (B) extracts a specified freezing line 741 corresponding to a specified freezing temperature described below from the profile 711 of the scanning line 700 by analysis. Then, as shown in FIG. 9C, the processes of FIGS. 9A and 9B are performed for all the scanning lines, and all the defined freezing lines 751 in the frozen region are acquired. FIG. 9D images the acquired specified freezing line 751, for example, creates a specified frozen area image 761 in which the peripheral edge (boundary) of the specified frozen area is indicated by a dotted line, and displays it superimposed on the micro TE images 606 to 612. To do.

  Here, an embodiment for discriminating the prescribed freezing region will be described. For example, the image signal intensity 711 is analyzed for a certain scanning line 700 with respect to the first micro TE image 606. That is, the image signal profile of the frozen feature pattern in which the image signal intensity 711 has a peak at the boundary between the frozen region and the unfrozen region of the lesioned part is acquired. The frozen feature pattern has two local maximum values 701 near the boundary between the frozen region and the unfrozen region, and a local minimum value 702 between them. The width of the image signal intensity 711 at the half value (= maximum value 701 -minimum value 702) of the minimum value 701 is defined as a half value width 731. Then, the image area within the half-value width 731 is determined as a prescribed frozen area having a prescribed temperature (−20 ° C.) or less.

  Here, the half-value width 731 of the freezing feature pattern is one temperature index corresponding to a specified temperature (−20 ° C.) or lower. Therefore, a certain allowable width or range can be set as the specified temperature using the half-value width 731 as an index. For example, the temperature of the actual freezing region is measured using a temperature measuring means such as a thermocouple, and the relationship data with the position of the freezing feature pattern (for example, the position of the half width) is accumulated in advance, A temperature index can be set.

  In this way, for the micro TE images 608, 610, and 612 obtained in time series, the freeze region analysis unit analyzes the image signal intensity profiles 712, 713, and 714 and stores the specified freeze lines 741 to 744 in the memory. Remember. Then, the specified freezing lines 751 to 754 that are a set of the specified freezing lines 741 to 744 are acquired and stored in the memory. The prescribed freezing lines 751 to 754 stored in this manner are two-dimensionally arranged to create a prescribed frozen region image 761 that shows the peripheral edge (boundary) of the prescribed frozen region with a dotted line, and is superimposed on the micro TE images 606 to 612. To display. Then, the prescribed frozen region image 761 is displayed so as to be superimposed on a lesion part of a normal MR image (not shown), and if the prescribed frozen region image 761 covers the lesion part, the operator objectively determines that the treatment is completed. be able to.

  Actually, since the ice ball image 631 and the prescribed freezing region image 761 are displayed on the micro TE images 606 to 612, the surgeon can perform the cryotherapy so that the treatment target region enters the prescribed freezing region image 761. . That is, in accordance with the growth of the ice ball, the above-described freezing treatment is repeated, and the treatment ends when the prescribed region finally covers the treatment region.

  FIG. 10 shows a graphic user interface (GUI) display example during cryotherapy according to the present invention. 3D volume imaging is performed using the 3D imaging button 801. As the captured image, a three-axis image 831 to 833 and a volume rendering image 834 are displayed. Next, a specific area rendering button 802 is pressed to detect a volume of a specific area (segmentation) 813 as a target from the 3D image. Moreover, you may set the warning area | region containing a specific area | region as needed. In addition, the approach direction of the frozen probe 36 may be calculated using the treatment planning function. At this time, a route that hinders a route such as a lung or a bone is considered in advance. In this way, the operation simulation function is also used in the navigation software. By pressing a treatment parameter button 803, treatment device setting information is input, and detailed information such as a parameter 817 is set. Here is an example of a cryotherapy device. Information such as the type of needle used, ice ball diameter, ice internal rendering method, specified temperature, absolute image threshold, micro TE image threshold, margin, etc. are input and displayed, and navigation is started Pressing the button 804 activates the related software and starts surgery. Further, when the navigation button 804 is pressed, a real-time video including the simulated image 317 of the frozen probe 36 is displayed in the screen 811. Further, the simulated image 317 of the frozen probe 36 and the specific region / target 813 are also displayed in different colors. At the same time, patient information and surgical information necessary for the operation are also displayed so that the situation can be grasped visually. Information details such as patient information and treatment devices are also displayed, and the depth of the frozen probe and various parameters are also displayed. Further, a preset treatment parameter 817 is displayed. These information values can be changed during treatment, and can be freely changed at any time by pressing the parameter button 803.

  On the other hand, when the navigation image button 804 is pressed, the volume rendering image 834 is displayed in addition to the three-axis cross sections 831 to 833, and the simulated image 317 of the frozen probe 36 can be superimposed on the image. Furthermore, a treatment scheduled area 320 corresponding to the frozen probe 36 can also be displayed. In addition, by setting a specific area (treatment area, etc.), a target 813, and a warning area, the volume rendering image 834 can be superimposed and displayed in addition to the triaxial cross-sectional images 831 to 833. Freezing treatment can be performed using image information. Although the center of the three-axis cross section is generally set in the treatment planned area, the frozen probe 36 and the frozen probe 36 and the treatment planned area 320 can always be displayed.

  Further, the 3D image can be changed in real time by pressing the image information change button 805, and can be freely displayed at the request of the operator. These images can be MRI, CT, and US images that have been captured in advance, but real-time images captured on the spot can also be used. The treated region 837 can be displayed superimposed on the image obtained by the course of treatment, so that the remaining treatment region can be seen at a glance.

  Here, when the micro TE imaging Ice-Ball monitoring button 806 is pressed in the MR apparatus I, MR imaging is started, and the micro TE image 818 and the normal MR image 820 are displayed. By pressing the treatment start button 808 and the Ice-ball analysis button 807, the shape recognition and the internal defined area of the ice ball 821 are automatically processed 819, calculated, and displayed on the GUI. Also, it has a function of determining whether or not the target specific area 819 is within the specified area 822 and presenting it to the operator using sound and color information. The surgeon can use this information to monitor the progress of treatment. In addition to preventing human errors, cryotherapy accuracy that does not depend on the operator can be established, and the time required for cryotherapy can be shortened.

  Further, the cryotherapy system of the present invention has a function of determining whether or not the additional cryotherapy can be performed by determining whether or not the frozen area and the specified frozen area covered the predetermined treatment target area by the frozen area analysis unit by image processing. Can be provided.

  In addition, the imaging unit of the present invention captures an MR image of a living body including a lesion by multi-slice or three-dimensional imaging, and the freezing region analysis unit performs prescribed freezing based on the multi-slice or three-dimensional MR image. A region image can be created in three dimensions.

Further, the cryotherapy system of the present invention includes an imaging unit that captures an MR image of a living body including the lesioned part that is cryotreated by a cryoprobe punctured into a lesioned part of the living body, and a display unit that displays the MR image. The imaging unit includes a first echo signal and a second echo signal corresponding to a first echo time of less than 1 millisecond and a second echo time of several milliseconds or more. Are repeatedly executed, and a first MR image corresponding to the first echo signal and a second MR image corresponding to the second echo signal are generated in time series from the start of treatment by the cryoprobe. Then, the first MR image can be superimposed on the second MR image and displayed on the display unit.
In addition, a freezing region analysis unit that discriminates a predetermined freezing region below a predetermined specified temperature based on the first time-series MR image is provided, and the freezing region analysis unit scans the first time-series MR image. Then, the specified frozen area is determined based on the frozen feature pattern in which the intensity of the image signal peaks at the boundary between the frozen area and the unfrozen area of the lesion, and an image showing the specified frozen area is generated to display the time series of the display unit. The first MR image can be displayed superimposed on the first MR image.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to these, It is possible to implement in the form deform | transformed or changed in the range of the main point of this invention. It will be apparent to those skilled in the art that such variations or modifications belong to the present invention.

DESCRIPTION OF SYMBOLS 1 ... MRI apparatus, 3 ... Upper magnet, 5 ... Lower magnet, 7 ... Support | pillar, 9 ... Position detection device, 11 ... Arm, 13, 14 ... Monitor, 15 ... Monitor support part, 17 ... Reference tool, 19 ... Personal computer 21 ... Bed, 23 ... Control unit, 24 ... Patient, 25 ... Infrared camera (position detection device), 27 ... Pointer, 29 ... Surgeon, 33 ... RS232C cable, 34 ... Video recording device, 35 ... Reflecting sphere, 36 ... Cryoprobe, 38 ... Monitor for cryotherapy apparatus, 40 ... Cryotherapy apparatus

Claims (7)

A magnetic resonance imaging apparatus comprising: an imaging unit that captures an MR image of the living body including the lesioned part that is subjected to cryotherapy by a cryoprobe punctured in a lesioned part of the living body; and a display unit that displays the MR image With
The imaging unit repeats an imaging sequence of an echo time in which the contrast of the MR image inside the frozen region frozen by the frozen probe can be depicted, and images the time-series MR images from the start of treatment by the frozen probe. A cryotherapy system that displays a temperature distribution image inside the frozen region of the lesion on the display unit. Furthermore, based on the MR images in time series, a freezing region analysis unit for determining a specified freezing region below a predetermined temperature,
The frozen region analysis unit acquires a time-series image signal of the MR image, scans the MR image, and the intensity of the image signal appears at a peak at the boundary between the frozen region and the unfrozen region of the lesioned part. 2. The prescribed frozen region is determined based on a feature pattern, an image showing the prescribed frozen region is generated, and is displayed superimposed on the time-series MR image of the display unit. Cryotherapy system.   The cryotherapy system according to claim 2, wherein the frozen region analysis unit determines an image region corresponding to a half-value width of a minimum value of the frozen feature pattern as the specified frozen region.   The cryotherapy system according to any one of claims 1 to 3, wherein an echo time of the imaging sequence is less than 1 millisecond.   The frozen region analysis unit has a function of determining whether or not additional frozen treatment is possible by determining whether or not the frozen region and the prescribed frozen region covered a predetermined treatment target region by image processing. 5. The cryotherapy system according to any one of 1 to 4. The above imaging unit captures the MR image of the living body including the lesioned part by multi-slice or three-dimensional imaging,
The said frozen area analysis part produces the said defined frozen area image in three dimensions based on multi-slice or three-dimensionally picked-up MR image, The one of Claim 1 thru | or 5 characterized by the above-mentioned. Cryotherapy system. A magnetic resonance imaging apparatus comprising: an imaging unit that captures an MR image of the living body including the lesioned part that is subjected to cryotherapy by a cryoprobe punctured in a lesioned part of the living body; and a display unit that displays the MR image With
The imaging unit repeatedly executes an imaging sequence for respectively acquiring a first echo signal and a second echo signal corresponding to a first echo time of less than 1 millisecond and a second echo time of several milliseconds or more. The first MR image corresponding to the first echo signal and the second MR image corresponding to the second echo signal are generated in time series from the start of treatment by the cryoprobe, and the second MR image is 1 MR image is superimposed and displayed on the display unit,
A freezing area analysis unit for determining a specified freezing area below a predetermined temperature based on the first MR image in time series,
The frozen region analysis unit scans the first MR image in time series, and the prescribed frozen region is based on a frozen feature pattern in which the intensity of the image signal appears at the boundary between the frozen region and the unfrozen region of the lesioned part. A cryotherapy system that generates an image indicating the prescribed frozen region and displays the image superimposed on the time-series first MR image of the display unit.

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