JP2015181533A - Image diagnostic apparatus and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for measuring sensitivity simply in an environment on the utilization side of an image diagnostic apparatus without preparing a special device.SOLUTION: Line data obtained by performing Fourier transform to light interference data are analyzed, and first data between the inner surface and the outer surface of a catheter sheath and second data between a rotation center position of a light transmission/reception part and a lens surface of the light transmission/reception part are detected. Then, the sensitivity of an image diagnostic apparatus is calculated based on the first and second data.

Description

  The present invention relates to an image diagnostic apparatus and a control method thereof.

  An optical coherence tomography (OCT: Optical Coherence Tomography) using a catheter in which an imaging core that transmits and receives light is rotatably accommodated at the distal end and is movable in the axial direction is used as an apparatus for acquiring an image of a blood vessel lumen. There is. Further, as an improved type of OCT, an optical coherence tomography (SS-OCT) using wavelength sweep has been developed (Patent Document 1). Hereinafter, these are collectively referred to as an image diagnostic apparatus.

  In the final process of manufacturing the diagnostic imaging apparatus, sensitivity inspection of the apparatus is performed. In general, the intensity of the reflected light is detected by directing the measurement light to an object (usually a mirror) from which a known reflected light is obtained without using a catheter and using a dedicated measuring device. Thus, the sensitivity of the diagnostic imaging apparatus is calculated. If the sensitivity calculated in this step deviates from the preset allowable range, it is assumed that there is some abnormality in the device, and the process goes back to the part replacement step through a second inspection step.

JP 2007-267867 A

  As described above, an image diagnostic apparatus generally used in a medical institution is one that has passed at least the sensitivity test. On the other hand, the sensitivity gradually increases due to deterioration over time, particularly the decrease in the output of the light source. It can happen to decline. In addition, when an optical path such as a part of a fiber or a joint is damaged due to some strong impact, the fiber may drop at a stroke. If the sensitivity decreases at a stroke, it can be said that it is obvious at a glance compared to the blood vessel cross-sectional images obtained so far. However, if the degree of aging or damage is small, the resulting blood vessel cross-sectional image is dark overall. It is hard to notice it even if you are an expert. In addition, the sensitivity may increase with a slight change from the adjustment position of the light source or a change in the output of the reference light.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a technique for easily measuring sensitivity in an environment on the side of using an image diagnostic apparatus without preparing a special apparatus. .

In order to solve the above problems, for example, an image diagnostic apparatus of the present invention has the following configuration. That is,
An image diagnostic apparatus using optical interference that reconstructs a cross-sectional image in a blood vessel using a catheter in which an optical transmission / reception unit is rotatably accommodated near the tip,
An analysis means for analyzing line data obtained by performing Fourier transform on optical interference data;
Calculation means for calculating the sensitivity of the diagnostic imaging apparatus based on the analysis result of the line data by the analysis means.

  According to the present invention, it is possible to easily measure the sensitivity within the environment on the side using the diagnostic imaging apparatus without preparing a special apparatus.

1 is an external view of a diagnostic imaging apparatus according to an embodiment. It is a block block diagram of an image diagnosis. It is a figure for demonstrating the process concerning the production | generation of an optical cross-sectional image. It is a sectional structure figure of the tip part of a catheter in an embodiment. It is a figure which shows the example of line data. It is a flowchart which shows the process which concerns on the sensitivity calculation in embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a diagram showing an example of the overall configuration of an optical tomographic image diagnostic apparatus (hereinafter simply referred to as an image diagnostic apparatus) 100 according to an embodiment of the present invention. In the embodiment, an apparatus using a wavelength swept light source is taken as an example. However, since it can be applied to an apparatus using a single wavelength light source, it should be recognized that the use of a wavelength swept light source is merely an example.

  The diagnostic imaging apparatus 100 includes a catheter 101, a pull-back unit 102, and an operation control device 103. The pull-back unit 102 and the operation control device 103 are connected by a cable 104 via a connector 105. The cable 104 accommodates an optical fiber and various signal lines.

  The catheter 101 accommodates an optical fiber rotatably. At the tip of this optical fiber, the light (measurement light) transmitted from the operation control device 100 via the pullback unit 102 is transmitted in a direction substantially perpendicular to the central axis of the optical fiber, and the transmitted light An imaging core having an optical transmission / reception unit for receiving reflected light from outside is provided.

  The pullback unit 102 holds the optical fiber in the catheter 101 via an adapter provided in the catheter 101. The imaging core provided at the tip of the catheter 101 can be rotated by rotating the optical fiber in the catheter 101 by driving a motor built in the pullback unit 102. The pullback unit 102 also drives a motor provided in the built-in linear drive unit to pull the optical fiber in the catheter 101 at a predetermined speed (which is called a pullback unit).

  With the above-described configuration, the catheter 101 is guided into the patient's blood vessel, the radial scanning motor (reference numeral 241 in FIG. 2) built in the pullback unit 102 is driven, and the optical fiber in the catheter 101 is rotated. It is possible to scan the lumen surface over 360 degrees. Further, the pullback unit 102 pulls the optical fiber in the catheter 101 at a predetermined speed, whereby scanning along the blood vessel axis is performed. As a result, a plurality of tomographic images along the blood vessel axis viewed from the inside of the blood vessel can be obtained, and these can be connected to reconstruct a three-dimensional blood vessel image.

  The operation control device 103 has a function of comprehensively controlling the operation of the diagnostic imaging apparatus 100. The operation control device 103 has, for example, a function of inputting various setting values based on a user (doctor) instruction into the device and a function of processing data obtained by measurement and displaying it as a tomographic image in the body cavity.

  The operation control device 103 includes a main body control unit 111, a printer / DVD drive 111-1, an operation panel 112, an LCD monitor 113, and the like. The main body control unit 111 generates an optical tomographic image. The optical tomographic image generates interference light data by causing interference between reflected light obtained by measurement and reference light obtained by separating light from the light source, and is generated based on the interference light data. It is generated by processing the line data.

  The printer / DVD drive 111-1 prints the processing result in the main body control unit 111 or stores it as data. The operation panel 112 is a user interface through which a user inputs various setting values and instructions. The LCD monitor 113 functions as a display device and displays, for example, a tomographic image generated by the main body control unit 111. Reference numeral 114 denotes a mouse as a pointing device (coordinate input device).

  Next, the functional configuration of the diagnostic imaging apparatus 100 will be described. FIG. 2 is a block configuration diagram of the diagnostic imaging apparatus 100. Hereinafter, the functional configuration of the wavelength sweep type and diagnostic imaging apparatus will be described with reference to FIG.

  In the figure, reference numeral 201 denotes a signal processing unit that controls the entire diagnostic imaging apparatus, and is composed of several circuits including a microprocessor. Reference numeral 202 denotes a memory (RAM) provided in the signal processing unit 201. Reference numeral 210 denotes an external storage device that stores a program to be executed by the signal processing unit 201 and various data (including a table described later and a plurality of programs for calculating a refractive index), and is typically a hard disk. . Reference numeral 203 denotes a wavelength sweep light source, which sweeps light of different wavelengths over time.

  The light output from the wavelength swept light source 203 is incident on one end of the first single mode fiber 271 and transmitted toward the distal end side. The first single mode fiber 271 is optically coupled to the fourth single mode fiber 275 at an intermediate optical fiber coupler 272.

  The light emitted from the optical fiber coupler 272 in the first single mode fiber 271 to the tip side is guided to the second single mode fiber 273 via the connector 105. The other end of the second single mode fiber 273 is connected to the optical rotary joint 230 in the pullback unit 102.

  On the other hand, the catheter 101 has an adapter 101 a for connecting to the pullback portion 102. Then, the catheter 101 is stably held by the pullback unit 102 by connecting the catheter 101 to the pullback unit 102 by the adapter 101a. Further, the end of the third single mode fiber 274 rotatably accommodated in the catheter 101 is connected to the optical rotary joint 230. As a result, the second single mode fiber 273 and the third single mode fiber are optically coupled. At the other end of the third single mode fiber 274 (the leading portion side of the catheter 101), an imaging core 250 on which a mirror and a lens that emit light in a direction substantially perpendicular to the rotation axis is mounted is provided.

  As a result, the light emitted from the wavelength swept light source 203 passes through the first single mode fiber 271, the second single mode fiber 273, and the third single mode fiber 274 to the end of the third single mode fiber 274. Guided to an imaging core 250 provided in the section. The imaging core 250 emits this light in a direction orthogonal to the axis of the fiber, receives the reflected light, and the received reflected light is led backwards this time and returned to the operation control device 103.

  On the other hand, an optical path length adjustment mechanism 220 for finely adjusting the optical path length of the reference light is provided at the opposite end of the fourth single mode fiber 275 coupled to the optical fiber coupler 272. This optical path length variable mechanism 220 serves as an optical path length changing means for changing the optical path length corresponding to the variation in length so that the variation in length of each catheter 101 when the catheter 101 is exchanged and used can be absorbed. Function. Therefore, a collimating lens 225 located at the end of the fourth single mode fiber 275 is provided on a movable uniaxial stage 224 as indicated by an arrow 226 in the optical axis direction.

  Specifically, when the catheter 101 is replaced, the uniaxial stage 224 functions as an optical path length changing unit having a variable range of the optical path length that can absorb variations in the optical path length of the catheter 101. Further, the uniaxial stage 224 also has a function as an adjusting means for adjusting the offset. For example, even when the distal end of the catheter 101 is not in close contact with the surface of the living tissue, the optical path length can be minutely changed by the uniaxial stage so that the reflected light from the surface position of the living tissue can be interfered. Is possible.

  The optical path length is finely adjusted by the uniaxial stage 224, and the light reflected by the mirror 223 via the grating 221 and the lens 222 is again guided to the fourth single mode fiber 275, and the first optical fiber coupler 272 The light obtained from the single mode fiber 271 side is mixed and received as interference light by a photodiode 204 (hereinafter referred to as PD).

  The interference light received by the PD 204 in this way is photoelectrically converted, amplified by the amplifier 205, and then input to the demodulator 206. The demodulator 206 performs demodulation processing for extracting only the signal portion of the interfered light, and its output is input to the A / D converter 207 as an interference light signal.

  The A / D converter 207 samples the interference light signal for 1024 points at 45 MHz, for example, and generates one line of digital data (interference light data). The sampling frequency of 45 MHz is based on the assumption that about 90% of the wavelength sweep period (25 μsec) is extracted as 1024 digital data when the wavelength sweep repetition frequency is 40 kHz. There is no particular limitation.

  The line-by-line interference light data generated by the A / D converter 207 is input to the signal processing unit 201 and temporarily stored in the memory 202. In the signal processing unit 201, the interference light data is subjected to frequency decomposition by FFT (Fast Fourier Transform) to generate data in the depth direction (line data), and this is coordinate-converted to obtain data at each position in the blood vessel. An optical section image is constructed and output to the LCD monitor 113 at a predetermined frame rate.

  The signal processing unit 201 is further connected to an optical path length adjustment driving unit 209 and a communication unit 208. The signal processing unit 201 controls the position of the uniaxial stage 224 (optical path length control) via the optical path length adjustment driving unit 209.

  The communication unit 208 incorporates several drive circuits and communicates with the pullback unit 102 under the control of the signal processing unit 201. Specifically, an encoder for supplying a driving signal to the radial scanning motor 241 for rotating the third single-mode fiber by the optical rotary joint 230 in the pull-back unit 102 and detecting the rotational position of the radial scanning motor. Reception of a signal from the unit 242 and supply of a drive signal to the linear drive unit 243 for pulling the third single mode fiber 284 at a predetermined speed.

  Note that the above processing in the signal processing unit 201 is also realized by a predetermined program being executed by a computer.

  FIG. 4 is a cross-sectional view of the vicinity of the distal end of the catheter 101. The catheter 101 is composed of a catheter sheath 410 made of a transparent member, and accommodates therein an imaging core 250 that is rotatable and movable along the axis of the catheter 101. The imaging core 250 includes an optical transmission / reception unit 512 and a housing 411 that accommodates the optical transmission / reception unit 512. The housing 413 is supported by the drive shaft 414. The drive shaft 414 is a material that is flexible and can transmit rotation well. For example, the drive shaft 414 is made of a metal such as stainless steel. A third single mode fiber 274 is accommodated inside the drive shaft 414. The housing 411 has a notch in a part of a cylindrical metal pipe. The optical transmission / reception unit 412 transmits and receives light through the notch.

  The optical transmission / reception unit 412 is provided at the end of the third single mode fiber 274 and has a hemispherical shape obtained by cutting the sphere at an angle of approximately 45 degrees with respect to the vertical plane of FIG. The part is formed. Further, the optical transmission / reception unit 412 has a hemispherical shape, and thus has a lens function. The light supplied via the third single mode fiber 274 is reflected by this mirror part and emitted toward the vascular tissue along the arrow 472a shown in the figure. During scanning, the light is emitted inside the blood vessel. The optical transmission / reception unit 412 receives the reflected light from the vascular tissue indicated by the arrow 472b shown in the figure, reflects it at the mirror unit, and returns the reflected light to the third single mode fiber 274.

  In the above configuration, when the distal end of the catheter 101 is inserted until the distal end of the catheter 101 is positioned in the affected part (coronary artery) to be diagnosed by the patient, the user releases the flush liquid from the distal end of the guiding catheter via a guiding catheter (not shown). Perform the operation. Then, the operation panel 112 is scanned to input an instruction to start scanning. When this instruction input is detected, the signal processing unit 201 drives the wavelength swept light source 232 to generate light, and supplies measurement light to the optical transmission / reception unit 412 in the imaging core 250. Further, the signal processing unit 201 drives the radial scanning motor 241 and the linear drive unit 243 in the pullback unit 102 to perform a scanning process (a process of rotating the imaging core 250 and pulling at a predetermined speed). As a result, the optical interference data is stored in the memory 202, and the tomographic image reconstruction process is performed using the set refractive index of the flash solution as a parameter.

  Here, a process for generating one optical cross-sectional image will be described with reference to FIG. This figure is a view for explaining the reconstruction processing of the cross-sectional image of the blood vessel 301 in which the imaging core 250 is located. The imaging core 250 transmits and receives the measurement light a plurality of times during one rotation (360 degrees). With one transmission / reception of light, data of one line in the direction of irradiation with the light can be obtained. Accordingly, 512 line data extending radially from the rotation center 302 can be obtained by transmitting and receiving light 512 times, for example, during one rotation. The 512 line data are subjected to fast Fourier transform, and the value of each pixel in one line is determined. Each line is dense in the vicinity of the rotation center position and becomes sparse with distance from the rotation center position. Therefore, the pixels in the empty space of each line are generated by performing a known interpolation process, and a two-dimensional cross-sectional image that can be seen by humans is generated. A three-dimensional blood vessel image can be obtained by connecting the generated two-dimensional cross-sectional images to each other. Note that when the optical cross-sectional image is reconstructed, three concentric circles 303 a to 303 c are generated in the vicinity of the rotation center 302 of the imaging core 250. These are shadows caused by the light emitted from the optical transceiver 412 being reflected by the lens surface 412a and the boundary surface between the inner surface 410a and the outer surface 410b of the catheter sheath 410 (see FIG. 4 for each surface). I want to be) Reference numeral 304 shown in the figure is a shadow of a guide wire that guides the catheter 101 to the affected area. Actually, since the guide wire is made of metal and does not transmit light, an image of the back side portion of the guide wire cannot be obtained as viewed from the rotation center position 302. It should be recognized that the illustration is only a conceptual diagram.

  The outline of the configuration and operation of the diagnostic imaging apparatus in the embodiment has been described above. Next, the principle of sensitivity detection, which is a feature according to the present invention, will be described.

  As described in the background art, the sensitivity inspection is performed by the manufacturer using a dedicated inspection apparatus at the manufacturing stage of the diagnostic imaging apparatus. Therefore, the user (medical institution) cannot inspect the same sensitivity as the manufacturer. However, the sensitivity is also true that the sensitivity deteriorates over time. If the sensitivity can be grasped with an appropriate accuracy, it is possible to predict in advance the time of deviating from the allowable range, and it is possible to take a precaution for that. Therefore, it can be said that grasping the sensitivity is meaningful for the user side. Although the present inventor is not as accurate as a dedicated inspection apparatus, the present inventor has come up with a technique for easily obtaining sensitivity within the range of the user's usage environment. Details will be described below.

The sensitivity is a value at a point where the optical path difference is 0, and is expressed by the following equation (1).
Sensitivity (dB) = {SNR (dB) at optical path difference 0} − {Sample reflectance (dB)} (1)
Here, the “sample reflectance” is a value (dB) calculated by “10 · log (reflected light amount (mW) / output light amount (mW))” that can be calculated when a reflector is used. In the embodiment, it is noted that the space between the inner side surface 410a and the outer side surface 410b of the catheter sheath 410 is resin that does not include blood, water, air, and the like, and the reflectance of the portion can be regarded as known (fixed) And it was considered suitable as “Sample” here. “SNR at zero optical path difference” can be obtained by subtracting the background noise level from the actually measured reflected light intensity in this sample (inside the material of the sheath 410). As the background noise level, it is desirable to use a signal of a part that does not depend on the medium under the same situation as when “Sample” is measured. The inventor considered that a signal detected as “reflected light” from the center of rotation to the lens surface 412a of the optical transceiver 412 can be regarded as background noise.

  This will be described in more detail with reference to FIG. This figure shows line data obtained by FFT conversion. The horizontal axis represents the distance from the rotation center (in the embodiment, 1024 pieces of pixel data are generated, so the range is from 0 to 1023), and the vertical axis represents the pixel value of each pixel constituting the line data ( Reflection intensity).

As already described, the second peak 502 from the rotation center position corresponds to the inner surface 410a of the catheter sheath 410, and the third peak 503 corresponds to the outer surface 410b. Therefore, the intensity of the reflected light in the portion occupied by the resin in the catheter sheath 410 is between the peaks 502 and 503. In the embodiment, the “valley bottom” between the peaks 502 and 503 is the reflected light intensity S _{A at the} target position. It should be noted that the reflected light intensity at the center position between the peaks 502 and 503 may be just an example.

Since the first peak 501 corresponds to the lens surface 412a of the light transmitting / receiving unit 412, the average value of the reflected light intensity from the origin to the inside by a preset pixel from the lens surface 412a is determined as background noise. It was recognized as the strength S _B.

Although the above is derived from the data for one line in FIG. 5, in order to improve the accuracy, 512 lines obtained when the imaging core 250 makes one rotation are obtained, and the average value of each is obtained as a final value. S _A and S _B were used.

Therefore, the required sensitivity S (dB) is in accordance with equation (1):
S (dB) = {SNR (dB) at 0 optical path difference} − {Sample reflectance (dB)}
= {S _A -S _B }-{C} (2)
In the above equation (2), “C” is known and is a value stored in advance in the external storage device 210. The values S _A and S _B are actually measured values derived from actual interference light data. And although the sensitivity S obtained by said formula was not the same precision as a dedicated sensitivity inspection apparatus, it confirmed that it had sufficient precision as an index value showing a sensitivity for a general user.

  The principle of sensitivity calculation in the embodiment has been described above. The timing for calculating the sensitivity S may be any timing as long as the optical path length adjustment mechanism 220 is controlled and adjustment (calibration) is performed to make the optical path difference between the measurement light and the reference light zero. . For example, the calculation may be made with reference to line data obtained by actually scanning the patient's blood vessel. Here, an example in which the power of the diagnostic imaging apparatus is turned on and the sensitivity is calculated in a process subsequent to the calibration process will be described with reference to the flowchart of FIG. Note that the program according to the flowchart of FIG. 3 is stored in the external storage device 210.

  When the power of the diagnostic imaging apparatus is turned on, the signal processing unit 201 executes calibration processing in step S601. The calibration process is a process that controls the optical path length adjustment mechanism 220 based on the user's operation to match the optical path lengths of the reference light and the measurement light, and is a known process. Therefore, although not described in detail here, in the process, line data is generated from the actually measured interference light data. Therefore, at the stage where the calibration is completed, the line data in a state where there are optical path lengths of the measurement light and the reference light are stored and held in the memory 202. Therefore, in step S602, the signal processing unit 201 refers to the line data for one rotation (512 in the embodiment) of the imaging core 250 in the memory 202, and performs the above-described calculation processing to obtain the current sensitivity. S is obtained. Then, the signal processing unit 201 additionally records the obtained sensitivity S and the current date and time in the external storage device 210 as log information. As a result, the sensitivity and date / time information are accumulated in time series in the external storage device 210 each time the apparatus is started.

  In step S604, it is determined whether the calculated current sensitivity is within a preset allowable range. If the calculated sensitivity is out of the range, it is considered that a normal cross-sectional image cannot be reconstructed in step S606, and the LCD monitor 113 indicates that the calculated sensitivity (for example, red) is out of the allowable range. The error shown is displayed and the process is terminated. In addition, when error notification processing is performed, it is desirable not to proceed to subsequent processing.

  On the other hand, if it is determined in step S604 that the calculated current sensitivity is a normal value (within an allowable range), the process proceeds to step S605. In step S605, since the calculated sensitivity S is a normal value, the sensitivity S is displayed in blue. Furthermore, a process of predicting a time (out of the allowable range upper limit value or lower limit value) is predicted from past sensitivity information including the recorded current sensitivity and date. Specifically, in a two-dimensional coordinate system with the date as the horizontal axis and the sensitivity as the vertical axis, a linear equation that approximates the log information is calculated using the least square method. Then, the date and time when the straight line indicated by the equation intersects with the threshold value may be obtained. In step S607, the calculated predicted time is compared with the next scheduled maintenance date stored in the external storage device 210. If the predicted time is in the near future, the process proceeds to step S608, where the sensitivity is within the allowable range. Notify the user that there is a possibility that the predicted time to go out will be before the regular inspection, and call attention. Note that the accuracy of the forecast time may be, for example, monthly.

  The embodiment according to the present invention has been described above. According to the present embodiment, it is possible to know the sensitivity on the user side using the diagnostic imaging apparatus, although it is simple. In addition, by using the sensitivity, it is possible to grasp the remaining period during which the reliability of the cross-sectional image can be maintained due to the decrease in sensitivity, and it is possible to effectively use the maintenance plan.

In the flowchart of FIG. 6, the following processing of Example 1 and Example 2 may be performed immediately after Step S608.
[Example 1] Based on the sensitivity calculated in step S602, the output of the wavelength swept light source 203 or the output of reference light (usually realized by aperture adjustment) is adjusted. The sensitivity is corrected under the adjustment. When the corrected sensitivity exceeds the correctable range, it means that the sensitivity can no longer be adjusted, and this is notified.
[Example 2] Based on the sensitivity calculated in step S602, the gain or dynamic range of the interference light data is adjusted. Then, the sensitivity is corrected under the adjustment. When the corrected sensitivity exceeds the correctable range, it means that the sensitivity can no longer be adjusted, and this is notified.

  In the embodiment, the example in which the sensitivity calculation process is performed immediately after the calibration process has been described. However, if there is line data, the sensitivity of the apparatus when the line data is obtained can be obtained. In other words, if there is past clinical data (line data obtained by scanning and FFT conversion), the data is analyzed to determine the sensitivity of the apparatus when obtaining the clinical data. It is also possible.

In the embodiment, the values S _A and S _B are average values of values obtained from 512 line data obtained by one rotation of the imaging core 250. However, in order to increase the calculation speed, Of the 512 line data, the line data may be obtained at an appropriate interval (for example, line data at intervals of one line).

  In the present embodiment, an example in which the present invention is applied to an image diagnostic apparatus using optical interference using OCT or OFDI has been described. Recently, an imaging core has not only an optical transmission / reception unit but also an ultrasonic transmission / reception unit, and there is also a device that generates a cross-sectional image using optical interference and a cross-sectional image using ultrasonic waves in one scan. You may apply to.

Claims (12)

An image diagnostic apparatus using optical interference that reconstructs a cross-sectional image in a blood vessel using a catheter in which an optical transmission / reception unit is rotatably accommodated near the tip,
An analysis means for analyzing line data obtained by performing Fourier transform on optical interference data;
An image diagnostic apparatus comprising: a calculating unit that calculates sensitivity of the image diagnostic apparatus based on an analysis result of line data by the analyzing unit. The analysis means includes, based on the line data, first data between an inner surface and an outer surface of the sheath of the catheter, and a second data between a rotation center position of the optical transmission / reception unit and a lens surface of the optical transmission / reception unit. Including detection means for detecting data;
The image diagnostic apparatus according to claim 1, wherein the calculation unit calculates a sensitivity of the image diagnostic apparatus based on the first and second data obtained by the detection unit.   The detection means detects three peaks from the rotation center position in the line data, and sets data located between the second and third peaks to the first data and from the rotation center position to the first peak. The image diagnosis apparatus according to claim 2, wherein the data is detected as the second data.   The image diagnosis apparatus according to claim 2, wherein the detection unit is executed during a calibration process of the image diagnosis apparatus.   2. The apparatus according to claim 1, further comprising: a determination unit that determines whether or not the sensitivity calculated by the calculation unit is within a preset allowable range, and determines that the sensitivity is abnormal when the sensitivity is outside the allowable range. 5. The diagnostic imaging apparatus according to any one of 4 above.   The image diagnosis according to any one of claims 1 to 5, further comprising storage means for storing the sensitivity calculated by the calculation means and the date and time calculated by the calculation means in association with each other as log information. apparatus. Prediction means for predicting the time when it falls outside the preset allowable range based on the log information;
The diagnostic imaging apparatus according to claim 6, further comprising: an informing unit that informs the time predicted by the predicting unit.   The image diagnosis apparatus according to claim 7, wherein the notification unit performs a notification process when the predicted time is in the near future from the next maintenance time.   The image diagnostic apparatus according to claim 1, further comprising a correction unit that corrects the sensitivity calculated by the calculation unit. A method of controlling an image diagnostic apparatus using optical interference that reconstructs a cross-sectional image in a blood vessel using a catheter in which an optical transmission / reception unit is rotatably accommodated near the tip,
An analysis process for analyzing line data obtained by performing Fourier transform on the optical interference data;
And a calculation step of calculating the sensitivity of the image diagnostic apparatus based on the analysis result of the line data in the analysis step.   The program for making a computer perform each step of the method of Claim 10 by making a computer read and run.   A computer-readable storage medium storing the program according to claim 11.

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