Vol. 16, #2

Infrared Thermographic Visualization Of The
Traditional Chinese Acupuncture Meridian Points
Veerasak Narongpunt, BE
Pierre Cornillot, MD
Jean-Raymond Attali, MD
Frederic Molinier, DVM
David Alimi, MD
Stefan Datcu, PhD
Laurent Ibos, PhD
Yves Candau, PhD
Bernard Fontas, PhD
Ahmed Raji, PhD
Bernard Clairac, PhD
Suzanne Bloch Danan, PhD
Michel Marignan, MD

ABSTRACT
Background The relationship between acupuncture points and physiology has not been subjected to many well-designed trials.
Objectives To evaluate and describe the results of an experimental infrared scanning protocol to detect the heat emission of acupuncture points in the Bladder Meridian stimulated by acupressure, and their influence up and downstream on the meridian.
Design A study of 12 healthy volunteers subjected to acupressure on specific Bladder Meridian acupuncture points that resulted in heat emission measured by an experimental infrared camera and software processing.
Setting The study was conducted in the laboratory of the Thermal Department (CERTES) of the University Paris XII in Créteil, near Paris, France.
Subjects Twelve healthy volunteers (aged 20-56 years: 6 females and 6 males) who had previously not had acupuncture.
Interventions The acupressure stimulus was a 2-minute modulated finger pressure on the left side of point BL 2. This 2-minute stimulation had a rhythm of 3 seconds of pressure followed by a 1-second pause without releasing skin contact; 2 minutes rest before acupressure stimulation; then, 2 minutes of acupressure stimulation; and finally, 2 minutes or more after acupressure.
Main Outcome Measures Heat was generated on specific acupuncture points as a consequence of the acupressure stimulation.
Results Acupressure on BL 2 produced the highest amount of heat emission on BL 67.
Conclusion Unknown neurovascular effects of the organism may explain the high-speed thermal activity on the dorsum foot point BL 67. The mechanism is unknown but measurable.
KEY WORDS
Acupressure, Infrared Heat, Bladder Meridian, Acupuncture Points, Infrared Camera, Traditional Chinese Acupuncture, Meridian Points, Heat Emission, Thermography

INTRODUCTION
Traditional Chinese acupuncture (TCA) and Oriental medicines are based on the theory of energy equilibrium in harmony with the universe. Acupuncture points play a key role in regulating this vital energy of human life. Historically, the detection of acupuncture points was based on impedance techniques,1-9 i.e., the measurement of low impedance points on the skin surface corresponding to acupuncture points. Unfortunately, the electrode placement on the skin can produce interfacing artifacts that interfere with proper electrical impedance measurements. We use infrared thermography (IRT), which localizes the traditional Chinese acupuncture meridian points (TCAMPs).

The traditional conception of TCAMP is based on the interconnection between the skin surface and the internal organs. Unfortunately, this relationship between the TCAMPs and the human body has not been properly demonstrated by scientific trials.10

Standard clinical thermographic practice stipulates a skin surface temperature difference of 0.5° C or greater as an indication of a clinical significant change or pathology. An increasing number of studies have been conducted on the biophysical characteristics of the acupuncture points in humans and animals by heat criteria.11-23

Healthy volunteers were selected in such a way as to confirm that any warm phenomenon was able to be induced by an acupressure24 stimulation on the human skin surface.

The purpose of this study was to demonstrate that IRT detection of thermal emission was the result of acupressure stimulation on a TCAMP.

MATERIALS AND METHODS
Subjects
Twelve healthy university student volunteers (6 females/6 males; aged 20-56 years) were enrolled. None of the subjects were previously treated with any form of acupuncture.

Figure 1. Different points to simulate around the eye

Figure 2. On each foot back, the Bladder's TCAMP are shown


Acupuncture Techniques
Acupuncture points: BL 2 was the point stimulated by acupressure. BL 65, BL 66, and BL 67 (Figures 2, 4, and Table 1) served as observation points on the bladder meridian. These choices excluded any anatomic known links and any local vascular influences during a quasi-instantaneous thermal reaction.

Placebo acupressure stimulation (AS) point was the LI 4 (Figure 3 and Table 2). The sham AS point (a non-acupoint) was located inter-mediately between BL 2 and HN 3 (extra point) (Figures 1 and 4, and Table 2).

Acupressure Technique
The stimulus was a 2-minute modulated
finger pressure on the left side of point BL 1. This 2-minute stimulation had a rhythm of 3 seconds of pressure followed by 1-second pause without releasing skin contact; 2 minutes rest before acupressure stimulation; then, 2 minutes of acupressure stimulation; and finally, 2 minutes or more following acupressure.

Protocol Technique
Acquisition of Infrared Images

  1. Recording of infrared images was performed by a digital IR camera: Agema 570 Elite, FLIR Systems.
  2. The bundle, Researcher RT 2000 FLIR Systems, including a PCMCIA card and acquisition software, to process the IR image (thermogram) on a PC computer at 7 images/second maximum.
  3. Equipment was housed in a steady state laboratory environment. The relative humidity and mean temperature of the air were measured by a thermo-hygrometer (HANNA Instruments HI 8564).

Figure 3. Location of the Large Intestine point LI 4 (Hegu) for placebo acupressure stimulation

A subject was placed in a comfortable position on an inclined chair. The left foot was put in a polystyrene plate inside of which a K-type thermocouple was superficially inserted in order to survey the temperature of the foot's sole during the test session. The thermocouple was connected to a Keithley 2000 Multimeter. The thermocouple signal was conditioned and cold junction compensated and converted into a temperature scale using the internal calibration of the multimeter. The temperature resolution was about 0.01 K (Kelvin) or 1 mK. The IR camera was placed approximately 1 m from the subject's left foot dorsum. This stable position of the foot reduced micro-movement perturbations of the foot's dorsum and minimized visualizing angle deviations in relation to the detector's instantaneous visual field. This selected scanning facilitated our study avoiding a complex, IR imaging re-wedging software (Figure 5) error correction. Figure 6 shows an IR image of a subject's left dorsum foot and the zone of interest (BL 67).

The IR measurements were sequenced into the 3 phases of acupressure treatment as previously described. The thermogram's acquisition of the foot's dorsal skin surface was carried out during all 3 phases at the rate of 1 image every 5 seconds (0.2 Hz). Before
starting the manipulation, the subject was invited to acclimate to the laboratory environment until temperature stabilization of the sole of the foot was obtained.

Table 1. The selected TCAM Points of the Urinary Bladder

Code

Name

Location

BL2

Zanzhu

Directly above BL 1, in supraorbital notch, at the medial end of eyebrow

BL65

Shugu

Posterior lateral edge of the head of metatarsa 5

BL66

Zutonggu

Hollow anterior inferior to metatarsophalangeal joint 5

BL67

Zhiyin

0.1 Cun from posterior edge of nail-root of little toe, lateral side

 

Table 2. Stimulated points not on the Bladder Meridian (sham and placebo acupuncture)

Code

Name

Location

LI 4

Hegu

Hand-dorsum, between metacarpals 1-2, midway down 2nd metacarpal

HN 3

Yuyao

In the middle of the eyebrow

GB 44

Zuqiaoy in

0.1 Cun posterior to the corner of the nail on the lateral side of the 4th toe

ST 45

Lidui

0.1 Cun posterior to the corner of nail on the lateral side of the 2nd toe

LR 1

Dadun

On the lateral side of the big toe, 0.1 cun from the corner of the nail



Image Processing
The simple visualization of the infrared images did not show true temperature variations. In order to emphasize these variations, several treatments were performed to obtain: IRT signal(s) drift corrections and contrast image computations. As a means to emphasize the temperature variation during the experiment, a contrast image was computed by subtracting the first IR image in the considered sequence from each IR image of the sequence. The thermogram's signal and image processing (TSIP) was applied to all experimental outcomes.

RESULTS
Figure 7 depicts an IR image of the left (lateral-outside) foot which is acquired at the 10th second after the start-up of the acupressure procedure. The right, right up-sided temperature scale of the IR image corresponds with the "apparent" temperature computed with the skin's emission of "1." The "apparent" temperature means that the IR radiance received on each detector's element is converted into a temperature value by using the skin's emission of 1. Consequently, the given temperature is not precisely the actual skin's temperature. The human skin's emission is slightly lower than the perfect black body, which is 1.

Figure 4. The Acupuncture BL Stimulation Schematic Diagram



Figure 8 is an IR image of the same dorsum of foot. The image is acquired at the 4th minute (i.e., at the 2nd minute after the start of acquisition). The "Hot Spot" (Figure 8) is clearly seen around the expected point BL 67 of the Bladder TCAM. The IR image is displayed by using the same apparent temperature scale as the previous thermogram (Figure 7).

Figure 9 depicts an IRT graph of the 12 subjects' responses that were computed according to the TSIP. We plotted the maximum value of each participant every 30 seconds. Each modulated, acupressure stimulation produced a different generalized long-lasting effect for each subject.

Table 3. Technical specifications of the camera

Field of view

45° x 34°

Instantaneous field of view

2.45 mrad

Spectral range

7.5 - 13 µm

Accuracy

+/- 2% of range

Image size

320 x 240 pixels

 

Table 4. Object parameters used for
infrared image acquisition

Relative Humidity

50%

Camera Object-Distance

1M

Ambient Temperature

20° C

Atmospheric Temperature

20° C

E (Skin's Emissivity)

1

T (Atmospheric Transmission Factor)

1



A warming-up effect was observed by the TSIP (increasing at least 2° C nearby and around the extremities of the points: GB 44, LR 1, and BL 67), especially around the last one – the point BL 67 (Tables 1 and 2, and Figure 9). There was a general tendency to return to the initial state, except for 2 of the volunteers who continued reacting after acupressure treatment. During the stimulating time interval (2-4 minutes), the general thermal change of the patient's left foot was around 2.5° C + 5 or more. There were thermal deterministic signals (clearly emerging from the measurement's noise) caused by the acupressure treatment. We also saw a high effect around the lateral (outside) side of the great toe (close to the point LR 1, the extreme edge of this toenail) induced by the modulated AS.

Figure 10 shows the graph of the 6 subjects' IRT responses, according to the same stimulation protocol. Only the stimulus was applied between points BL 2 and HN 3 – "sham test mode." We observed that the maximum value of the subjects' temperature was about 0.6° C (Figures 1 and 10). Our placebo acupuncture treatment (stimulus on the acupoint LI 4) showed a similar increasing temperature level to about 0.5° C maximum (Figure 11).

The non-pertinent stimulated TCA points (LI 4 "Placebo Acupuncture Treatment" and between BL 2-HN 3 "Sham Acupuncture Treatment") did not involve a significant rise in temperature of such an identified region on the same left foot (Figures 9-11).

The basic infrared image processing allowed computing a contrast image. The processed contrast image represented a non-drifted differential temperature field on the subject's dorsum area of the foot. Therefore, for a stationary thermal scene (i.e., no variation of the temperature field on the target scene), we attempted to obtain a uniform contrast image. Actually, the infrared measured signal was intrinsically monotonous and very noisy due to the use of an electro-optical system (i.e., the IR camera) with the thermal detector noise, the electronic digital noise, converting noise, etc. But the contrast image processing of a quasi-steady thermal scene gives an acceptable result by a noise compensating differential mode between 2 noisy crude thermograms. This assumption of experimental stability is demonstrated by the contrast images obtained at the 1st part of the manipulation, when the subjects were at rest (Figure 7).

Figure 5. Synopsis of Experimental IR Scanning Protocol



Figure 12 was obtained from an infrared image acquired during the acupressure stimulation (Figure 8) on the same volunteer. We noticed that the differential thermal field was highly nonuniform. We can identify 3 peaks, corresponding to a differential thermal response of the 3 dorsal toes of the same foot under stimulation just 4 minutes after the experiment starting time. From an IRT viewpoint, we could not accurately determine the real amplitude of the relative temperature. There were many parameters that we must take into account in order to give a real absolute temperature, e.g., the contribution of the environment's reflection or the IR emission of the atmospheric layer between the camera and the foot skin surface.25,26 We assumed that the emission variation with respect to the temperature can be neglected because we obtained a small variation of temperature around 5° C, but we cannot state anything else very accurate about the skin's emission variation with respect to the viewing angle. We assumed that a zero mean Gaussian noise altered the camera-measured signal. The standard deviation of the noise was about 100 mK at 303 K, the value given by the camera's manufacturer.

Figure 7. Thermogram of the dorsum of the left foot at rest, at 10 seconds

Figure 8. Thermogram of the dorsum of the same foot and the "hot spot" around the expected point BL 67, at 4 minutes



The experimental set-up ensured a fairly normal position of the camera to the scanned surface of the subject's foot dorsal skin.

The differential apparent temperature field was computed by using the object's parameters presented in Table 4. Previous studies25 showed that the human skin emission was near to 1. In a first approximation, we demonstrated a relationship between the real differential temperature and the apparent one.

Nevertheless, if there was no variation of temperature surface, we may have obtained a uniform noisy contrast image. If there was a temperature change on the foot surface relative to a reference time, and if this variation was higher than the detector's noise equivalent temperature detection, the contrast image would present peaks and valleys.

DISCUSSION
Unknown neurovascular effects of the organism may explain the high-speed thermal activity on the dorsum foot point BL 67.27-30 A second hypothesis of the non-invasive mechanical action of the acupressure stimulation may even involve a "higher" involvement of the central nervous system. What is important is that we were able to measure with our experimental apparatus a change in thermal reactivity under the action of the acupres-sure. The heat emission could also be under the influence of a homeostasis re-equilibrium due to thermodynamic transformations of energy expenditures.31

CONCLUSION
We have demonstrated evidence of the existence of several TCAMPs by IRT during acupressure stimulation. Our TCA meridian test points were identifiable to the Bladder Meridian (BL); namely, BL 2 and BL 67, which had the most important heat effect.13 We may presume that TCAMPs are "visible" to IRT imaging over some parts of the human body. Further research will be necessary to expand on our preliminary results. Refined instrumentation and software such as a 2-point-to-point IRT image comparison will be key elements to further explore thermal emissions on the meridians.

ACKNOWLEDGEMENTS
The authors gratefully acknowledge the following people for their assistance with this article: Miss Sabrina Salvatore and Mrs Véronique Bourzaix of the University XIII of Bobigny for their coordinating assistance; the services of CERTES and LERISS Laboratories of the University Paris XII; Mr. Jacques Lemoine, Head of LERISS; Monsieur Benaoumeur Bourras; Dr Richard C. Niemtzow, Editor-in-Chief of Medical Acupuncture; and Mr Jean-Claude Frichet, Electricity of France.

Figure 9. The curve of outcomes of a formula acupressure stimulation starting at 2 minutes

Figure 10. The non-pertinent stimulated TCA non-acupoint:
"Sham Acupuncture Treatment"

Figure 11. The non-pertinent stimulated TCA acupoint: LI 4 "Placebo Acupuncture Treatment"

Figure 12. Apparent differential temperature on the left foot dorsum surface of a volunteer after 2 minutes of stimulation



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AUTHORS' INFORMATION
Veerasak Narongpunt has a BE and is working toward a PhD in Biomedical Science, and was the initiator of this multidisciplinary project.
Veerasak Narongpunt, BE*
Phone: +33-6-8670-2329
E-mail: narongpunt@univ-paris12.fr; narongpunt@laposte.net; narongpuntfr@yahoo.fr
        
Dr Pierre Cornillot is the Medical University Professor Emeritus (exceptional class) of the Faculty of Medicine, Health and Human Biology and Natural Medicines, at the University Paris XIII of North-Paris (Bobigny).
Pierre Cornillot, MD, PhD
E-mail: pierre.cornillot@free.fr

Dr Jean-Raymond Attali is Professor of Endocrinology at the Verdier Hospital, near Paris, France. Dr Attali is also the Responsible of the TCA Department of the Faculty of Natural Medicine of the University Paris XIII.
Jean-Raymond Attali, MD
E-mail: jr.attali@jvr.ap-hop-paris.fr

Dr Frederic Molinier is aspecialist in Acupuncture and Canine Osteopathy in France, and author of Traite d'Acupuncture Veternaire des Carnivores (3 volumes).
Frédéric Molinier, DVM
E-mail: cabinet.molinier@free.fr

Dr David Alimi is a Neurophysiologist and Associate Professor of Auricular Acupuncture at the Faculty of Medicine in Paris, France.
David Alimi, MD
E-mail: alimi@club-internet.fr

Stefan Datcu has a PhD in Thermal Science and Energetic Systems, and is Assistant Professor with the Networks and Telecom Department, University of Paris XII.
Stefan Datcu, PhD
E-mail: datcu@univ-paris12.fr

Laurent Ibos has a BE in Physics and a PhD in Electronic Materials and Technologies, and is
Assistant Professor and joined CERTES (Centre d'Etudes et Recherche Thermique et Systèmes) at the University Paris XII.
Laurent Ibos, PhD, BE
E-mail: ibos@univ-paris12.fr

Yves Candau has an ME and PhD in Energetics Sciences, and is Head of the Thermal Sciences Research Laboratory (CERTES – Centre d'Etudes et Recherche Thermique et Systèmes) at the University Paris XII of Créteil, France.
Yves Candau, ME, PhD
E-mail: candau@univ-paris12.fr

Bernard Fontas has a PhD in Physiology, and is an Assistant Professor in Physiology at the University Paris 12 of Créteil, France.
Bernard Fontas, PhD
E-mail: fontas@univ-paris12.fr

Ahmed Raji has a PhD in Physics, and is Assistant Professor at the University Paris XII.
Ahmed Raji, PhD
E-mail: raji@univ-paris12.fr

Bernard Clairac has a PhD and ScD in Physics, and a PhD in Sciences, and is Assistant Professor at the University Paris XII.
Bernard Clairac, PhD, ScD
E-mail: clairac@univ-paris12.fr

Suzanne Bloch Danan (Retired) has a PhD in Physical Chemistry, and was Assistant Professor (Out-graded Class) of Bio-Physical Chemistry at the University Paris XII; former Attache Assistant Professor of Biochemistry in the Faculty of Medicine of Paris XI; and was Visiting Searcher at the Weizmann of Rehovot, Israel.
Suzanne Bloch Danan, PhD
E-mail: Suzanne.bloch@noos.fr

Dr Michel Marignan specializes in Surgery, Auricular Acupuncture, and Posturology, and is Professor of Auricular Acupuncture at the GLEM (Groupe Lyonnais d'Etudes Médicales) in Lyon, France, where he is the Scientific Research Responsible.
Michel Marignan, MD, PhD
E-mail: marignan@online.fr

*Correspondence and reprint requests

 

 

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