Method for evaluating percutaneous intracavity treatment effect of lower limb artery disease based on infrared thermal imaging technology

Abstract

The invention discloses a method for evaluating the percutaneous intracavity treatment effect of lower limb artery diseases based on an infrared thermal imaging technology. The method comprises the following steps: respectively taking infrared thermograms of double lower limbs of a subject before and after percutaneous intracavity treatment by adopting a medical infrared thermal imager; performing ultrasonic examination on the shank of the operative limb to obtain anterior tibialis artery, posterior tibialis artery and peroneal blood flow before and after treatment; detecting the toe oxygen saturation of the operative limb foot to obtain the toe oxygen saturation of the operative limb foot before and after treatment; the blood pressure and pulse detector is used for checking the ABI of the operative limb and collecting the ratio of the ankle artery systolic pressure to the upper arm systolic pressure of the operative limb before and after the treatment of the patient; the infrared thermograms of the two lower limbs before and after treatment, the blood flow of the anterior tibialis artery, the posterior tibialis artery and the peroneal artery of the operative limb, the oxygen saturation of the foot toe of the operative limb and the ABI of the operative limb are analyzed, and a treatment effect result is obtained.

Description

Technical Field

[0001] The present invention relates to a method for evaluating the therapeutic efficacy, and particularly to a method for evaluating the therapeutic efficacy of percutaneous transluminal treatment of lower extremity arterial diseases based on infrared thermography technology. Background Art

[0002] Relevant epidemiological studies have shown that the overall prevalence of lower extremity arterial disease (LEAD) in the population is 3% to 10%, and currently, lower extremity arterial disease has become an indicator of systemic atherosclerosis. The clinical manifestations of LEAD are variable. The most common symptom is intermittent claudication, and in severe cases, rest pain, acral ulcers or gangrene may occur, and even amputation and death may occur.

[0003] Patients with severe lower limb ischemia will present with ischemic rest pain, ulcers or gangrene. The treatment principles for such patients include active surgical intervention, limb salvage and pain relief, improvement of limb function, reduction of cardiovascular risk factors, and control of other complications to prolong the patient's life. The common revascularization methods for LEAD include endovascular treatment and surgical treatment. There are many endovascular treatment techniques, such as percutaneous balloon angioplasty, stent implantation, atherectomy, laser angioplasty, cutting balloon, drug balloon, cryoballoon, and drug thrombolysis treatment or thrombectomy, etc. Surgical treatment can reconstruct the blood supply of the diseased area through anatomical bypass or extra-anatomical bypass. Currently, the main and first-line treatment method for patients with severe lower limb ischemia in clinical practice is percutaneous transluminal treatment.

[0004] The physical examination of LEAD includes dorsalis pedis pulse palpation, abdominal or inguinal auscultation and other examinations. There are many common diagnostic methods for LEAD, mainly including ankle-brachial index (ABI), duplex ultrasound (DUS), computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA). Through the above corresponding physical examinations and common imaging detection methods, the therapeutic efficacy of percutaneous transluminal treatment of lower extremity arterial diseases can be evaluated.

[0005] However, each of the above detection methods has its corresponding advantages and disadvantages. The currently commonly used objective efficacy evaluation methods for LEAD mainly include ankle-brachial index (ABI), duplex ultrasound (DUS), computed tomography angiography (CTA), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA). ABI is the most commonly used screening tool in clinical practice, but it is easily affected by vascular calcification. DUS has the advantages of being non-invasive, radiation-free, and economical, and it has currently become the preferred non-invasive detection tool for lower extremity arterial diseases. It provides extensive information on arterial anatomy and hemodynamics, but it does not show the vascular roadmap of the entire lower extremity and depends on the experience and skills of the operator. CTA, MRA, and DSA all provide vascular roadmaps. CTA can show vascular calcification and stents, but it has disadvantages such as radiation, nephrotoxicity, and allergies. MRA is expensive and has poor visibility of calcification and stents. DSA, as the "gold standard" for LEAD, has higher accuracy and clarity in vascular imaging, but it is invasive, and potential complications include hematoma, pseudoaneurysm, bleeding, arteriovenous fistula, and complications caused by contrast agents, such as contrast-induced nephropathy, contrast allergy reaction, contrast-induced hyperthyroidism, etc.

[0006] Given the current high prevalence of patients with severe limb ischemia, high amputation rate, and the occurrence of postoperative re-vascular occlusion events, there is an urgent need for a new detection tool, method, and system to evaluate the efficacy of percutaneous transluminal treatment, as well as an effective follow-up tool for postoperative monitoring. Summary of the Invention

[0007] The present invention provides a method for evaluating the efficacy of percutaneous transluminal treatment of lower extremity arterial diseases based on infrared thermography technology.

[0008] The technical solution provided by the present invention is: a method for evaluating the efficacy of percutaneous transluminal treatment of lower extremity arterial diseases based on infrared thermography technology, comprising the following steps:

[0009] Using a medical infrared thermography instrument (IRTI instrument) to respectively capture the infrared thermal images of the bilateral lower extremities of the subject before and after percutaneous transluminal treatment;

[0010] Performing ultrasound examination on the calf of the operative limb to obtain the blood flow of the anterior tibial artery, posterior tibial artery, and peroneal artery before and after treatment;

[0011] Detecting the toe oxygen saturation of the foot of the operative limb to obtain the toe oxygen saturation of the foot of the operative limb before and after treatment;

[0012] Using a blood pressure and pulse detector to examine the ABI of the operative limb and collecting the ratio of the systolic blood pressure of the ankle artery to the systolic blood pressure of the upper arm of the patient before and after treatment;

[0013] Analyze the infrared thermograms of both lower limbs before and after treatment, the blood flow of the anterior tibial artery, posterior tibial artery, and peroneal artery of the operative limb, the toe oxygen saturation of the operative limb foot, and the ABI of the operative limb to obtain the treatment efficacy results.

[0014] When collecting infrared images, the infrared lens should be preheated for more than 30 minutes. The patient is required to sit still about 1.5 - 3 meters away from the IRTI instrument, and the position and height of the infrared camera are adjusted. On the one hand, with the midpoint of the dorsum of the foot of the subject as the center point, the upper limit of the field of view should reach at least the ankle joint, the lower limit is the end of the toes, and the left and right boundaries fully cover the outer edge of the foot. Adjust the focal length to collect the infrared thermogram of the dorsum of the foot. On the other hand, the subject places both legs on the stool to expose the soles of the feet. With the midpoint of the sole of the foot of the subject as the center point, the upper limit of the field of view reaches the end of the toes, the lower limit reaches the heel, and the left and right boundaries fully cover the outer edge of the foot. Adjust the focal length to collect the infrared thermogram of the sole of the foot.

[0015] After collecting the infrared images, infrared image analysis is performed. According to the arterial course and supply area of the foot, the regions of interest on the dorsum of the foot are divided into Area 1, Area 2, Area 3, and Area 4, and the regions of interest on the sole of the foot are divided into Area 5, Area 6, Area 7, and Area 8. The dorsum of the foot is divided with the connecting line between the midpoints of the second and third toes and the ankle joint and the connecting line between the midpoints of the inner and outer edges of the foot as the dividing line, and the upper boundary reaches the ankle joint; the sole of the foot is divided with the connecting line between the midpoints of the second and third toes and the heel and the connecting line between the midpoints of the inner and outer edges of the foot as the dividing line. The 1 + 3 areas of the regions of interest on the dorsum of the foot and the 5 + 7 areas of the regions of interest on the sole of the foot are respectively the distal dorsum of the foot and the distal sole of the foot; the 2 + 4 areas of the regions of interest on the dorsum of the foot and the 6 + 8 areas of the regions of interest on the sole of the foot are respectively the proximal dorsum of the foot and the proximal sole of the foot.

[0016] When performing ultrasound examination on the calf of the operative limb, ultrasound examination is performed on the anterior tibial artery, posterior tibial artery, and peroneal artery of the operative limb, and the inner diameter through which the blood flow passes and the average blood flow velocity passing through it are measured to obtain the blood flow of the anterior tibial artery, posterior tibial artery, and peroneal artery. Blood flow (ml / min) = average blood flow velocity (cm / s) × cross-sectional area of blood flow (cm 2 ) × 60 s.

[0017] When examining the toe oxygen saturation of the operative limb foot, a finger clip pulse oximeter is used, with a measurement range of 70% - 100% and an accuracy of ±2%. During measurement, the sensor is placed on any toe of the patient's operative limb without tissue defect. It measures the oxygen absorption rate in the blood by infrared rays penetrating the skin and blood, thereby non-invasively measuring the toe oxygen saturation.

[0018] In the ABI examination of the operative limb, ABI refers to the ratio of the systolic blood pressure of the ankle artery (posterior tibial artery or dorsalis pedis artery) to the systolic blood pressure of the upper arm in the resting state. The systolic blood pressure of the upper arm is selected from the side with the higher value of the left and right arms. The normal value of ABI is 1.00 - 1.40, 0.91 - 0.99 is the critical value, and ABI ≤ 0.90 can be diagnosed as lower limb ischemia.

[0019] In the present invention, the ABI is the ratio of the systolic blood pressure of the dorsalis pedis artery to the systolic blood pressure of the upper arm, or the ratio of the systolic blood pressure of the posterior tibial artery to the systolic blood pressure of the upper arm.

[0020] In the present invention, preferably, the ratio of the systolic blood pressure of the dorsalis pedis artery to the systolic blood pressure of the upper arm is adopted.

[0021] In the present invention, LEAD patients meeting the indications for revascularization treatment are selected to undergo IRTI and ABI examinations respectively within 1 day before endovascular treatment and within 2 days after treatment.

[0022] Advantages of the present invention:

[0023] 1. The propagation characteristic of infrared radiation is that it can propagate in space without any material medium. This characteristic enables it to achieve non-contact detection, thus effectively avoiding interference factors and patient discomfort caused by direct contact, and at the same time significantly reducing the risk of cross-infection, which is particularly important for practical applications in the medical field. Further, visualization technology can precisely process complex thermal radiation data and convert it into an easily interpretable infrared pseudo-color thermal map. This graphical representation not only greatly improves the diagnostic accuracy, enabling doctors to quickly capture subtle changes in body temperature distribution; at the same time, its intuitiveness also enhances patients' understanding of their own health conditions, contributing to more effective communication between doctors and patients and the formulation of treatment plans.

[0024] 2. Contemporary medicine uses digital infrared thermal imaging technology to capture the far-infrared light waves released by the metabolism of human cells. After filtering, focusing, modulation, and photoelectric conversion, it displays the temperature distribution in the form of a pseudo-color thermal map to achieve qualitative and quantitative temperature analysis, providing accurate and intuitive data support for the diagnosis and efficacy monitoring of lower limb arterial diseases.

[0025] 3. The present invention uses a medical infrared thermal imager to non-contact and visually reflect the infrared thermal maps of LEAD patients before and after percutaneous transluminal treatment, so as to evaluate the treatment efficacy.

[0026] 4. As a safe, simple, and non-invasive detection tool, infrared thermal imaging can evaluate the severity of limb atherosclerotic diseases and the foot blood perfusion status, and can effectively and reliably evaluate the success of percutaneous transluminal treatment, which is an important supplement to lower limb vascular imaging examinations.

[0027] 5. Currently, the relevant domestic and foreign research mainly focuses on the diagnostic effectiveness and reliability of infrared thermography in LEAD. There are few studies on the evaluation of the efficacy of endovascular treatment. At the same time, these studies only analyze specific infrared - interested areas of the foot before and after treatment, rather than outlining and analyzing the entire infrared area of the foot, and there is no routine follow - up after surgery. However, the present invention outlines and analyzes the entire infrared area of the foot of LEAD patients before and after percutaneous transluminal treatment, and conducts postoperative follow - up to evaluate the effectiveness and reliability of infrared detection technology.

[0028] At the same time, previous inventions only used IRTI and ABI examinations to evaluate lower limb ischemia. However, the present invention also measures the toe oxygen saturation of the foot of the operative limb and the ultrasonic blood flow of the calf artery to conduct a systematic evaluation of the efficacy of percutaneous transluminal treatment from multiple indicators, aspects, and directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of infrared examination of the foot.

[0030] Figure 2 It is a schematic diagram of the arterial course of the foot and the infrared expression partition.

[0031] Figure 3 It is the pseudo - color coding of infrared thermography.

[0032] Figure 4 It is a comparison chart of the efficacy of balloon dilation + laser ablation of the right lower limb;

[0033] a1 and a2 are the infrared thermograms of both feet before treatment; b1 and b2 are the infrared thermograms of both feet within 2 days after treatment; c1 and c2 are the DSA results of the right superficial femoral artery before and after treatment. DETAILED DESCRIPTION OF THE INVENTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will fully describe the technical solutions in the embodiments of the present application in combination with the accompanying drawings in the embodiments of the present application to fully understand the objectives, effects, and application prospects of the present invention. The following embodiments are only used to clarify the present invention and do not limit the scope of application of the present invention. However, without departing from the spirit and essence of the present invention, any modification or replacement of the methods, steps, or culture conditions of the present invention belongs to the scope of the present invention.

[0035] (1) Instruments and equipment: Use a medical infrared thermograph to collect and analyze images, and use a medical blood pressure and pulse detector to obtain the ABI value.

[0036] (2) Environmental requirements: Keep the room temperature in the examination room relatively constant at 22 - 26°C, and the relative humidity at 40 - 60%; the examination room should have no air convection, no direct sunlight, no heat sources or cold sources, and the detection background should be a cold absorption screen without power wires, no reflection or reflection.

[0037] (3) Preparation before examination: The infrared detection lens should be preheated for more than 30 minutes before detection to ensure the stability of the infrared lens collection. Before the examination, the patient should avoid factors that affect infrared examination such as strenuous activities, smoking, and caffeine intake. At the same time, it is prohibited to apply ointments, gauze, etc. on the feet. If any, they should be removed. The patient should enter the examination room and rest for at least 10 minutes, with bare legs and feet, without pressing, scratching, or rubbing the skin of the examination area to maintain balance with the controlled environmental temperature.

[0038] (4) Detection method: Patients with LEAD undergo IRTI, ultrasound, toe oxygen saturation of the foot, and ABI examinations before and after percutaneous transluminal treatment.

[0039] (5) Infrared image acquisition: The infrared lens should be preheated for more than 30 minutes. The patient is required to sit still about 1.5 - 3 meters away from the IRTI instrument, and adjust the position and height of the infrared camera. On the one hand, with the midpoint of the dorsum of the foot of the subject as the center point, the upper limit of the field of view should reach at least the ankle joint, the lower limit should be the end of the toes, and the left and right boundaries should fully cover the outer edge of the foot. Adjust the focal length to collect the infrared thermal image of the dorsum of the foot. On the other hand, the subject places both legs on the stool to expose the soles of the feet. With the midpoint of the sole of the foot of the subject as the center point, the upper limit of the field of view reaches the end of the toes, the lower limit reaches the heel, and the left and right boundaries fully cover the outer edge of the foot. Adjust the focal length to collect the infrared thermal image of the sole of the foot. See the schematic diagram of image acquisition in Figure 1 。

[0040] (6) Infrared image analysis:

[0041] According to the arterial course and supply area of the foot, the regions of interest on the dorsum of the foot are divided into Zone 1, Zone 2, Zone 3, and Zone 4, and the regions of interest on the sole of the foot are divided into Zone 5, Zone 6, Zone 7, and Zone 8. The dorsum of the foot is divided by the connecting line between the midpoints of the second and third toes and the ankle joint and the connecting line between the midpoints of the inner and outer edges of the foot, with the upper boundary reaching the ankle joint; the sole of the foot is divided by the connecting line between the midpoints of the second and third toes and the heel and the connecting line between the midpoints of the inner and outer edges of the foot. See details in Figure 2 。Regions 1 + 3 and 5 + 7 are the distal dorsum of the foot and the distal sole of the foot respectively; Regions 2 + 4 and 6 + 8 are the proximal dorsum of the foot and the proximal sole of the foot respectively. The infrared thermal images of the subjects' feet are analyzed in the supporting infrared software.

[0042] ① Qualitative analysis: The infrared thermal imager converts the infrared radiation received by the human body into a visual infrared thermal image through photoelectric conversion and pseudo-color coding technology. Different colors represent different temperatures, such as Figure 3As shown, from high temperature to low temperature, they are: white (ultra-high temperature area), red (high temperature area), purple (hot area), yellow (warm area), green (cool area), blue (cold area), black (ultra-cold area).

[0043] ② Quantitative analysis: LEAD patients who meet the indications for revascularization treatment often have more collateral circulation formed in the lower limb arteries. Therefore, in this study, the average temperatures of 8 regions of interest on the foot, the dorsal foot region, and the plantar region were selected.

[0044] (7) Ultrasonic examination of the calf of the operative limb:

[0045] Using a portable ultrasonic examination instrument, ultrasonic examinations were performed on the anterior tibial artery, posterior tibial artery, and peroneal artery of the operative limb to measure the inner diameter through which the blood flows and the average blood flow velocity passing through it, so as to obtain the blood flow volumes of the anterior tibial artery, posterior tibial artery, and peroneal artery. Blood flow volume (ml / min) = average blood flow velocity (cm / s) × blood flow cross-sectional area (cm 2 ) × 60s.

[0046] (8) Toe oxygen saturation examination of the foot of the operative limb:

[0047] Using a finger clip type pulse oximeter, the measurement range is 70% - 100%, and the accuracy is ±2%. During measurement, the sensor is put on any toe of the operative limb of the patient without tissue defect, and it measures the oxygen absorption rate in the blood by infrared rays penetrating the skin and blood, so as to non-invasively measure the toe oxygen saturation.

[0048] (9) ABI examination of the operative limb:

[0049] ABI refers to the ratio of the systolic blood pressure of the ankle artery (posterior tibial artery or dorsal foot artery) to the systolic blood pressure of the upper arm in the resting state. The systolic blood pressure of the upper arm selects the side with the higher value of the left and right arms. In this embodiment, the ratio of the systolic blood pressure of the dorsal foot artery to the systolic blood pressure of the upper arm is uniformly adopted. The normal value of ABI is 1.00 - 1.40, 0.91 - 0.99 is the critical value, and ABI ≤ 0.90 can be diagnosed as lower limb ischemia.

[0050] Example

[0051] The patient is a 72-year-old male with intermittent claudication of both lower limbs for more than 2 years; diagnosis: arteriosclerosis obliterans of both lower limbs; DSA result: occlusion of the right superficial femoral artery; treatment method: right lower limb artery balloon dilation + laser ablation.

[0052] Within 2 days after the percutaneous transluminal treatment of this patient, the average temperatures (Tav) of areas 1, 2, 3, 4, 5, 6, 7, 8 of both feet and the foot were all higher than those before treatment. See Tables 1, 2 and Figure 4 .

[0053] The corresponding ABI value (0.52) of the patient's operative limb within 2 days after treatment was higher than that before treatment (0.3), and the toe oxygen saturation of the operative limb within 2 days after treatment (100%) was also higher than that before treatment (0%).

[0054] Temperature of the operative limb Tav(℃) 1 2 3 4 5 6 8 Foot Before treatment 29.75 31.77 29.87 31.72 29.81 30.33 29.54 30.17 Within 2 days after treatment 34.85 34.93 35.38 34.93 34.72 35.42 34.90 34.86

[0055] Table 1. Changes in the average foot temperature (Tav) of the patient's operative limb

[0056] Temperature of the non-operative limb Tav(℃) 1 2 3 4 5 6 7 8 Foot Before treatment 32.05 32.85 32.32 33.33 31.85 31.65 31.17 30.84 31.95 Within 2 days after treatment 32.71 33.66 33.00 34.77 32.19 33.08 31.44 31.92 32.62

[0057] Table 2. Changes in the average foot temperature (Tav) of the patient's non-operative limb

[0058] The above-described embodiments merely represent one implementation manner of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology, characterized in that: The following steps are involved: A medical infrared thermal imager was used to capture infrared thermal images of the subjects' lower limbs before and after percutaneous intracavitary treatment. Ultrasound examination of the lower leg of the operated limb was performed to obtain the blood flow of the anterior tibial artery, posterior tibial artery and peroneal artery before and after treatment; Detect the oxygen saturation of the toes of the operated limb and obtain the oxygen saturation of the toes of the operated limb before and after treatment; The ABI of the operated limb was checked by a blood pressure pulse detector, and the ratio of the systolic blood pressure of the ankle artery of the operated limb to the systolic blood pressure of the upper arm was collected before and after treatment; The infrared thermal images of both lower limbs before and after treatment, the blood flow of the anterior tibial artery, posterior tibial artery and peroneal artery of the operated limb, the oxygen saturation of the toes of the operated limb and the ABI of the operated limb were analyzed to obtain the treatment efficacy results.

2. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1 is characterized in that: When the medical infrared thermal imager is performing infrared image acquisition, the infrared lens should be preheated for more than 30 minutes, and the patient is required to sit quietly at a distance of about 1.5 to 3 meters from the IRTI instrument. The midpoint of the subject's dorsum of the foot is taken as the center point, the upper limit of the field of view is at least the ankle joint, the lower limit of the field of view is the end of the toes, the left and right boundaries fully cover the outer edge of the foot, and the focus is adjusted to acquire the dorsum infrared thermal image; the midpoint of the subject's sole is taken as the center point, the upper limit of the field of view is the end of the toes, the lower limit of the field of view is the heel, the left and right boundaries fully cover the outer edge of the foot, and the focus is adjusted to acquire the sole infrared thermal image.

3. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1 is characterized in that: When the medical infrared thermal imager performs infrared image analysis, the dorsum of the foot region of interest is divided into zone 1, zone 2, zone 3 and zone 4, and the plantar region of interest is divided into zone 5, zone 6, zone 7 and zone 8 according to the arterial course and supply area of ​​the foot; the dorsum of the foot region is divided by the line connecting the midpoint of the 2nd and 3rd toes with the ankle joint and the line connecting the midpoints of the inner and outer edges of the foot, and the upper boundary reaches the ankle joint; the plantar region is divided by the line connecting the midpoint of the 2nd and 3rd toes with the heel and the line connecting the midpoints of the inner and outer edges of the foot, wherein zone 1+3 of the dorsum of the foot region of interest and zone 5+7 of the plantar region of interest are the distal end of the dorsum of the foot and the distal end of the plantar of the foot, respectively; zone 2+4 of the dorsum of the foot region of interest and zone 6+8 of the plantar region of interest are the proximal end of the dorsum of the foot and the proximal end of the plantar of the foot, respectively.

4. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1 is characterized in that: When the ultrasonic examination of the calf of the operated limb is performed, the anterior tibial artery, posterior tibial artery and peroneal artery of the operated limb are ultrasonically examined to measure the inner diameter through which blood flows and the average velocity of blood flow through, thereby obtaining the blood flow of the anterior tibial artery, posterior tibial artery and peroneal artery.

5. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1 is characterized in that: In the examination of oxygen saturation of the toes of the operative limb, a finger-clip pulse oximeter is used, with a measurement range of 70% to 100% and an accuracy of ±2%.

6. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 5 is characterized in that: In the examination of oxygen saturation of the toes of the operated limb, during measurement, the sensor is placed on any toe of the patient's operated limb that has no tissue defect, and infrared rays penetrate the skin and blood to measure the absorption rate of oxygen in the blood, thereby non-destructively determining the toe blood oxygen saturation.

7. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1, characterized in that: In the ABI examination of the operated limb, the ratio of the patient's ankle artery systolic pressure to the upper arm systolic pressure is tested. The upper arm systolic pressure is selected on the side with the higher value of the left or right arm. ABI ≤ 0.90 is diagnosed as lower limb ischemia.

8. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 7 is characterized in that: The ABI is the ratio of the dorsalis pedis artery systolic pressure to the upper arm systolic pressure, or the ratio of the posterior tibial artery systolic pressure to the upper arm systolic pressure.

9. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 8, characterized in that: The ABI is the ratio of dorsalis pedis artery systolic pressure to upper arm systolic pressure.

10. The method for evaluating the efficacy of percutaneous endovascular treatment of lower extremity arterial disease based on infrared thermal imaging technology according to claim 1, characterized in that: LEAD patients who met the indications for revascularization were selected and underwent IRTI and ABI examinations within 1 day before and 2 days after endovascular treatment.

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