Refer to: Shlens M, Stoltz MR, Benjamin A: Orthopedic applications of liquid crystal thermography. West J Med 122: 367-370, May 1975
Orthopedic Applications of Liquid Crystal Thermography MICHAEL SHLENS, MD, MELVIN R. STOLTZ, MD, and ALFRED BENJAMIN, RBP, ARPS Los Angeles
Liquid crystal thermography can assist the clinician in evaluating inflammatory conditions or delineating viability of tissues by the differences in coloration that occur with the use of these unique substances. The technique has proved useful in studying hemophilia, tumors of the extremities, arthritis and vascular conditions, including the complications of diabetes.
THE VARIOUS clinical and physical properties of liquid cholesteric crystals have been known since the turn of the century. More recently advantage has been taken of these properties to study various subsurface conditions, particularly with regard to aerodynamic and electronic structures.' It has only been in the last ten years that the medical applications of liquid crystal thermography have been explored.2 3 The clinical application of liquid crystals in medicine involves skin application to define relative temperatures which are modified by underlying conditions. Some cholesterol ester derivatives in the liquid crystal form are highly sensitive to variations in skin temperature which they convert almost instantaneously into reversible color values.
Cholesteric liquid crystals
are
organic
com-
From the Orthopaedic Hospital, Los Angeles; Dr. Shlens is on the Teaching Staff, Dr. Stoltz is Director of the Children's Fracture Clinic and Mr. Benjamin is Head of the Audio-Visual Department. This study was supported by a grant from Lederle Laboratories and the color illustrations were underwritten by Lederle Laboratories, Pearl River, NY. Submitted June 25, 1974. Reprint requests to: M. Shlens, MD, 1127 Wilshire BoulevardSuite 1410, Los Angeles, CA 90017.
pounds which exhibit mechanical properties of liquids and optical properties of solids. The substance is unique in that the molecule is neither in a three dimensional array as in a solid nor in a free form as in a liquid. Instead, cholesteric liquid crystals form layers which are free to slide over one another or revolve around a fixed axis. This property is responsible for the color changes associated with differentials in temperature to the areas on which they are applied. Normally the liquid is colorless, but the molecules realign themselves in response to temperatures of adjacent substances.4 The colors that are produced are the reverse of the conventional color scheme associated with heat. The spectrum of colors produced from these substances begins with red at the cool end of the spectrum and progresses through green to deep blue for the warm end of the scale. The underlying base coat of black is visible when the recorded temperature is beyond either end of the temperature scale. We have used the technique discussed in this paper to study various orthopedic conditions including spina bifida, various types of tumors, THE WESTERN JOURNAL OF MEDICINE
367
LIQUID CRYSTAL THERMOGRAPHY
hemophilia,5 arthritis and various other inflammatory and vascular conditions. In addition, we have used this technique to objectively assess the benefits of treatment rendered for intra-articular inflammatory disease.
Materials and Methods The technique of application begins with obtaining a black background before the cholesteric crystals are applied. This can be accomplished either by applying a plastic sheet, such as the Vidrape that is used in surgery, that has been painted black, or by direct application of a black paint to the area to be investigated. The clear liquid cholesteric crystal solution is then sprayed on the area. Because the crystals are affected by subsurface temperature, variations in color appear.'; The area investigated is then photographed. A 35 mm single reflex camera is used, Ektachrome-x® is the preferred film. The camera is equipped with a rotating polarizing filter. Strobe light being a cool light is the most suitable light source. The flash unit, too, must be equipped with a polarizing filter, eliminating the reflections of the fatty cholesteric liquid crystals. The photographs are analyzed for areas of relative temperature differential. In the evaluation of joint disease, a baseline study is carried out and then follow-up studies are conducted at timely intervals to evaluate the effectiveness of the treatment program.
Clinical Uses In symptomatic but clinically undefined cases, liquid crystals may help to determine the site of inflammatory lesions. A common example is a patient with complaint of pain yet in whom no clinical signs of tissue disorder are found. In such cases the lesion can be localized and an estimate of the extent of the lesion, which may be inflammatory, traumatic, degenerative, infectious or neoplastic in origin, can be defined. The extent of inflammation from a synovitis is readily apparent through this technique. It is also a useful diagnostic aid in examining infants with myelodysplasia where sensory responses are unreliable yet skin temperature changes secondary to the paralysis are easily defined. The specific level of involvement can thus be objectively delineated and formulation of a treatment plan at a very early stage of disease is possible. Peripheral vascular disease is frequently more clearly defined with this technique, for example, the level of gangrenous 368
MAY 1975 * 122 * 5
changes in diabetes mellitus or in occlusive disease can be estimated.
Reports of Cases We have found the technique to be of use not only in diagnostic procedures but also in objectively following the results of treatment. The following represent several illustrative case reports. CASE 1. This case is that of a patient with bilateral plantar fasciitis. Clinically the patient had tender heels, more so on the left side than on the right, and walked with some difficulty. Calcaneal spurs bilaterally were seen on x-ray films. Figure la shows a preinjection thermogram, the blue area representing the area of the inflamed attachment of the plantar fascia to the os calcis. The symptomatic side, the left side, was injected with a combination of 1 percent solution of lidocaine and a cortisone derivative. The second thermogram (Figure lb) was taken three days after the injection and shows the change in hue which indicates decreasing underlying temperature and which correlated with the resolving of the inflammatory condition. This therapeutic benefit continued until approximately 26 days following initial injection. These thermographic findings correlated with the clinical response. CASE 2. A patient was seen with juvenile rheumatoid arthritis with severe involvement of all joints, particularly the small joints of the hand. The most involved joint was the metacarpophalangeal joint in the index finger of the left hand and this corresponded with the blue area on the initial thermogram (Figure 2a). An intraarticular injection of steroid and lidocaine was administered and serial thermograms made. Progression of thermographic change in color corresponded with clinical improvement throughout the course of follow-up which in this instance was six weeks (Figure 2b). CASE 3. A patient with juvenile rheumatoid disease involving primarily the knees was seen. The patient previously had synovectomy carried out on the left knee and at the time of thermography was known to be symptomatic in the right knee. The unoperated right side was injected with an intra-articular steroid and lidocaine combination and serial thermograms were made (Figures 3a and 3b). Return of the blue color corresponded with recurrence of symptoms after a symptomfree period of approximately three weeks. CASE 4. This patient, with classic hemophilia-A, presented with multiple joint hemorrhages par-
lb
la
9
2a
3a
ri
1.
i-
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.
p
o-
r.
L
1,
..
.1-
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r
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4a
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LIQUID CRYSTAL THERMOGRAPHY
ticularly in the left hand, as indicated by preconcentrate thermograms (Figure 4a). The patient was given plasma concentrate and thermograms were made again after ten minutes (Figure 4b). The change in color correlated with the clinical improvement and was consistent with the cessation of bleeding into the localized areas, and the resolving "hot spots" in the joints of the hands. CASE 5. This case is that of another patient with classic hemophilia-A, this one presenting with acute hemarthrosis of the knee. Figure 5a shows a thermogram of the involved knee before treatment. Figure 5b shows one made 20 minutes after plasma was given. A striking difference in color and also in the clinical appearance of the joints can be seen.
Liquid Crystals and Delineating the Extent of Various Orthopedic Conditions It should be stated at the outset that the diagnosis of an actual condition is not made using this technique; however, it is a valuable adjunct in determining and delineating the extent of the pathology to be encountered.8 Beginning with myelodysplasia, it is particularly of use when one considers the difficulty in assessing a sensory level in neurologic deficit in a newborn infant. A good example is seen in Figure 6 where the set-up point is in the midline below the level of the iliac crest and in the superior portion of the gluteal cleft. Again on another patient, one can see the black background on the extremity which indicates that the area is out of the temperature range tested compared to that more proximal area in the trunk where the blue coloration indicates warmer temperature, Figure 7, thus giving an indication of the level of the lesion. This technique is also applicable, as previously mentioned, to vascular conditions. In this regard, Figure 8 shows thermograms of a patient's right and left legs. The blue-green color of the uninvolved left leg is to be compared with the black to orange colors in the right lower extremity, which was pulseless. A second example of vascular disease (Figure 9) is that of a patient with Raynaud's disease. A differential in circulation can be seen in the patient's fingers.
370
MAY 1975 * 122 * 5
Crystal thermography can also be used to determine the presence and extent of various tumors. An example is a patient we saw with a cavernous hemangioma of the right hand. In the plain photograph (Figure 10a) one can see the bluish discoloration in the right palm. A thermogram (Figure 1Ob) shows the much larger extent of this tumor than one might previously have anticipated on the basis of the clinical appearance. A second example is that of a young patient seen with undifferentiated sarcoma of the right side. The obvious area of increased temperature is noted on the thermogram (Figure 11). A third example is that of a patient who presented with vague joint pain in the right knee. No abnormalities were noted on x-ray studies. A temperature differential between the two knees was seen on thermograms (Figure 12) and subsequent microscopic diagnosis of the lesion in question showed synovial sarcoma. Another patient presented with a tender area in the right distal femur noted approximately three months before being seen. Thermography showed the isolated area of increased temperature over a lesion which proved to be an osteochondroma of the distal femur (Figure 13).
Conclusions Liquid crystal thermography has limited general clinical application. However, the technique has proved to be a relatively simple method of studying various orthopedic conditions and determining the extent of the underlying pathology. It has also proved to be an objective way of evaluating the results of treatment in various inflammatory diseases. REFERENCES 1. Portnoy WM: Liquid crystal thermography. J Assoc Adv Med Instrum 4:176-181, Sep-Oct 1970 2. Tai PL: An investigation of clinical applications of mesomorphic cholesteric liquid crystals in podiatric medicine-A preliminary study. J Am Podiatry Assoc 63:119-128, Apr 1973 3. Ferguson JL: Liquid crystals. Sci Am 211:76, 1974 4. Criscy JT, Gordy E. Ferguson JL, et al: A new technique for the demonstration of skin temperature pattern. J Invest Dermatol 43:89, 1964 5. Benjamin A: Liquid Crystal Thermography. Hemophilia and the Regional Center Concept. R.D. 2522-M, HEW, Washington, DC, Nov 1971, pp 53-54 6. Benjamin A: Liquid crystal photography. Visual/Sonic Med 3: 10-16, Oct/Nov 1963 7. Benjamin A: How to eliminate reflections in cholesteric liquid crystal photography. Photographic Applications in Science, Technology and Medicine 6:30-31, Mar 1971 8. Benjamin A: Differential diagnosis with cholesteric liquid crystal photography. J Biol Photogr Assoc 41:13-14, Jan 1973
Orthopedic Applications of Liquid Crystal Thermography MICHAEL SHLENS, MD, MELVIN R. STOLTZ, MD, and ALFRED BENJAMIN, RBP, ARPS Los Angeles
Liquid crystal thermography can assist the clinician in evaluating inflammatory conditions or delineating viability of tissues by the differences in coloration that occur with the use of these unique substances. The technique has proved useful in studying hemophilia, tumors of the extremities, arthritis and vascular conditions, including the complications of diabetes.
THE VARIOUS clinical and physical properties of liquid cholesteric crystals have been known since the turn of the century. More recently advantage has been taken of these properties to study various subsurface conditions, particularly with regard to aerodynamic and electronic structures.' It has only been in the last ten years that the medical applications of liquid crystal thermography have been explored.2 3 The clinical application of liquid crystals in medicine involves skin application to define relative temperatures which are modified by underlying conditions. Some cholesterol ester derivatives in the liquid crystal form are highly sensitive to variations in skin temperature which they convert almost instantaneously into reversible color values.
Cholesteric liquid crystals
are
organic
com-
From the Orthopaedic Hospital, Los Angeles; Dr. Shlens is on the Teaching Staff, Dr. Stoltz is Director of the Children's Fracture Clinic and Mr. Benjamin is Head of the Audio-Visual Department. This study was supported by a grant from Lederle Laboratories and the color illustrations were underwritten by Lederle Laboratories, Pearl River, NY. Submitted June 25, 1974. Reprint requests to: M. Shlens, MD, 1127 Wilshire BoulevardSuite 1410, Los Angeles, CA 90017.
pounds which exhibit mechanical properties of liquids and optical properties of solids. The substance is unique in that the molecule is neither in a three dimensional array as in a solid nor in a free form as in a liquid. Instead, cholesteric liquid crystals form layers which are free to slide over one another or revolve around a fixed axis. This property is responsible for the color changes associated with differentials in temperature to the areas on which they are applied. Normally the liquid is colorless, but the molecules realign themselves in response to temperatures of adjacent substances.4 The colors that are produced are the reverse of the conventional color scheme associated with heat. The spectrum of colors produced from these substances begins with red at the cool end of the spectrum and progresses through green to deep blue for the warm end of the scale. The underlying base coat of black is visible when the recorded temperature is beyond either end of the temperature scale. We have used the technique discussed in this paper to study various orthopedic conditions including spina bifida, various types of tumors, THE WESTERN JOURNAL OF MEDICINE
367
LIQUID CRYSTAL THERMOGRAPHY
hemophilia,5 arthritis and various other inflammatory and vascular conditions. In addition, we have used this technique to objectively assess the benefits of treatment rendered for intra-articular inflammatory disease.
Materials and Methods The technique of application begins with obtaining a black background before the cholesteric crystals are applied. This can be accomplished either by applying a plastic sheet, such as the Vidrape that is used in surgery, that has been painted black, or by direct application of a black paint to the area to be investigated. The clear liquid cholesteric crystal solution is then sprayed on the area. Because the crystals are affected by subsurface temperature, variations in color appear.'; The area investigated is then photographed. A 35 mm single reflex camera is used, Ektachrome-x® is the preferred film. The camera is equipped with a rotating polarizing filter. Strobe light being a cool light is the most suitable light source. The flash unit, too, must be equipped with a polarizing filter, eliminating the reflections of the fatty cholesteric liquid crystals. The photographs are analyzed for areas of relative temperature differential. In the evaluation of joint disease, a baseline study is carried out and then follow-up studies are conducted at timely intervals to evaluate the effectiveness of the treatment program.
Clinical Uses In symptomatic but clinically undefined cases, liquid crystals may help to determine the site of inflammatory lesions. A common example is a patient with complaint of pain yet in whom no clinical signs of tissue disorder are found. In such cases the lesion can be localized and an estimate of the extent of the lesion, which may be inflammatory, traumatic, degenerative, infectious or neoplastic in origin, can be defined. The extent of inflammation from a synovitis is readily apparent through this technique. It is also a useful diagnostic aid in examining infants with myelodysplasia where sensory responses are unreliable yet skin temperature changes secondary to the paralysis are easily defined. The specific level of involvement can thus be objectively delineated and formulation of a treatment plan at a very early stage of disease is possible. Peripheral vascular disease is frequently more clearly defined with this technique, for example, the level of gangrenous 368
MAY 1975 * 122 * 5
changes in diabetes mellitus or in occlusive disease can be estimated.
Reports of Cases We have found the technique to be of use not only in diagnostic procedures but also in objectively following the results of treatment. The following represent several illustrative case reports. CASE 1. This case is that of a patient with bilateral plantar fasciitis. Clinically the patient had tender heels, more so on the left side than on the right, and walked with some difficulty. Calcaneal spurs bilaterally were seen on x-ray films. Figure la shows a preinjection thermogram, the blue area representing the area of the inflamed attachment of the plantar fascia to the os calcis. The symptomatic side, the left side, was injected with a combination of 1 percent solution of lidocaine and a cortisone derivative. The second thermogram (Figure lb) was taken three days after the injection and shows the change in hue which indicates decreasing underlying temperature and which correlated with the resolving of the inflammatory condition. This therapeutic benefit continued until approximately 26 days following initial injection. These thermographic findings correlated with the clinical response. CASE 2. A patient was seen with juvenile rheumatoid arthritis with severe involvement of all joints, particularly the small joints of the hand. The most involved joint was the metacarpophalangeal joint in the index finger of the left hand and this corresponded with the blue area on the initial thermogram (Figure 2a). An intraarticular injection of steroid and lidocaine was administered and serial thermograms made. Progression of thermographic change in color corresponded with clinical improvement throughout the course of follow-up which in this instance was six weeks (Figure 2b). CASE 3. A patient with juvenile rheumatoid disease involving primarily the knees was seen. The patient previously had synovectomy carried out on the left knee and at the time of thermography was known to be symptomatic in the right knee. The unoperated right side was injected with an intra-articular steroid and lidocaine combination and serial thermograms were made (Figures 3a and 3b). Return of the blue color corresponded with recurrence of symptoms after a symptomfree period of approximately three weeks. CASE 4. This patient, with classic hemophilia-A, presented with multiple joint hemorrhages par-
lb
la
9
2a
3a
ri
1.
i-
1:.
.
p
o-
r.
L
1,
..
.1-
-,I
,L ,.
r
';'"
4 4b
4a
*11
I
-1 "... ..N. :-. -.156,!., --A ': -., p-
1-
-L
j
W.-a
12
13
LIQUID CRYSTAL THERMOGRAPHY
ticularly in the left hand, as indicated by preconcentrate thermograms (Figure 4a). The patient was given plasma concentrate and thermograms were made again after ten minutes (Figure 4b). The change in color correlated with the clinical improvement and was consistent with the cessation of bleeding into the localized areas, and the resolving "hot spots" in the joints of the hands. CASE 5. This case is that of another patient with classic hemophilia-A, this one presenting with acute hemarthrosis of the knee. Figure 5a shows a thermogram of the involved knee before treatment. Figure 5b shows one made 20 minutes after plasma was given. A striking difference in color and also in the clinical appearance of the joints can be seen.
Liquid Crystals and Delineating the Extent of Various Orthopedic Conditions It should be stated at the outset that the diagnosis of an actual condition is not made using this technique; however, it is a valuable adjunct in determining and delineating the extent of the pathology to be encountered.8 Beginning with myelodysplasia, it is particularly of use when one considers the difficulty in assessing a sensory level in neurologic deficit in a newborn infant. A good example is seen in Figure 6 where the set-up point is in the midline below the level of the iliac crest and in the superior portion of the gluteal cleft. Again on another patient, one can see the black background on the extremity which indicates that the area is out of the temperature range tested compared to that more proximal area in the trunk where the blue coloration indicates warmer temperature, Figure 7, thus giving an indication of the level of the lesion. This technique is also applicable, as previously mentioned, to vascular conditions. In this regard, Figure 8 shows thermograms of a patient's right and left legs. The blue-green color of the uninvolved left leg is to be compared with the black to orange colors in the right lower extremity, which was pulseless. A second example of vascular disease (Figure 9) is that of a patient with Raynaud's disease. A differential in circulation can be seen in the patient's fingers.
370
MAY 1975 * 122 * 5
Crystal thermography can also be used to determine the presence and extent of various tumors. An example is a patient we saw with a cavernous hemangioma of the right hand. In the plain photograph (Figure 10a) one can see the bluish discoloration in the right palm. A thermogram (Figure 1Ob) shows the much larger extent of this tumor than one might previously have anticipated on the basis of the clinical appearance. A second example is that of a young patient seen with undifferentiated sarcoma of the right side. The obvious area of increased temperature is noted on the thermogram (Figure 11). A third example is that of a patient who presented with vague joint pain in the right knee. No abnormalities were noted on x-ray studies. A temperature differential between the two knees was seen on thermograms (Figure 12) and subsequent microscopic diagnosis of the lesion in question showed synovial sarcoma. Another patient presented with a tender area in the right distal femur noted approximately three months before being seen. Thermography showed the isolated area of increased temperature over a lesion which proved to be an osteochondroma of the distal femur (Figure 13).
Conclusions Liquid crystal thermography has limited general clinical application. However, the technique has proved to be a relatively simple method of studying various orthopedic conditions and determining the extent of the underlying pathology. It has also proved to be an objective way of evaluating the results of treatment in various inflammatory diseases. REFERENCES 1. Portnoy WM: Liquid crystal thermography. J Assoc Adv Med Instrum 4:176-181, Sep-Oct 1970 2. Tai PL: An investigation of clinical applications of mesomorphic cholesteric liquid crystals in podiatric medicine-A preliminary study. J Am Podiatry Assoc 63:119-128, Apr 1973 3. Ferguson JL: Liquid crystals. Sci Am 211:76, 1974 4. Criscy JT, Gordy E. Ferguson JL, et al: A new technique for the demonstration of skin temperature pattern. J Invest Dermatol 43:89, 1964 5. Benjamin A: Liquid Crystal Thermography. Hemophilia and the Regional Center Concept. R.D. 2522-M, HEW, Washington, DC, Nov 1971, pp 53-54 6. Benjamin A: Liquid crystal photography. Visual/Sonic Med 3: 10-16, Oct/Nov 1963 7. Benjamin A: How to eliminate reflections in cholesteric liquid crystal photography. Photographic Applications in Science, Technology and Medicine 6:30-31, Mar 1971 8. Benjamin A: Differential diagnosis with cholesteric liquid crystal photography. J Biol Photogr Assoc 41:13-14, Jan 1973
