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A method for recording eight physiologic events on the cinefluorogram
New Methods A Method
for Recording
Events
Eight
Physiologic
on the Cinefluorogram*
HENRY D. MCINTOSH,M.D.,
MARTIN
L. SCHEINER,
Durham,
North
B.E.E.~
and ROBERT E. WHALEN,
M.D.
Carolina
to permit analysis. These workers, therefore, abandoned this approach in favor of a system whereby light reflected from the moving stylus of a standard electrocardiographic machine was used to expose the cinefluorographic film. A telescopic lens and right-angle mirror system directed the light from the output phosphor of the image intensifier tube. The definition of the trace and the detail of the single frame of 16 mm. film was said to be inadequate for detailed analysis, but it did afford a point of reference for timing. A tine-trace unit developed for our laboratory permits the data recorded by any or all of the eight channels of an Electronics for Medicine DR-8 recorder to be simultaneously recorded with the image from the output phosphor of an image intensifier on individual frames of 35 mm. This is accomplished cinefluorographic film.* by utilizing the output of the DR-8 recorder to drive a specially designed slave oscilloscope. Initially the choice of an appropriate tube for the slave oscilloscope presented problems. Standard long persistence phosphors were re,jected after a number of experiments. Regardless of the phosphor or the amount of voltage used, all suffered from the same defect: With a light level sufficient to produce an image of sufficient persistence for a second or two, the intensity of the initial spot was so high as to greatly overexpose the film and make difficult the recognition of the moment in time represented by the particular frame. When the light level was set to give reasonable exposures for the initial
URING the last decade technics for documenting rapidly changing mechanical and electrical physiologic events with photographic recorders have been greatly improved. Similar advances have been made in recording the functional anatomy by means of cinefluorography. It would naturally follow that the clinical physiologist would attempt to utilize both technics simultaneously to correlate physiologic with anatomic changes. To accomplish such a correlation, it is necessary either (1) to identify the physiologic event (recorded on paper) that occurs coincident with specific anatomic changes recorded on an individual cinefluorographic frame, or (2) to simultaneously, the cinefluorographic expose film to both a light beam containing the physiologic data and the light beam from the image intensifier containing the anatomic information. The first method has been used in a number of laboratories. This method utilizes a capacitor, discharged by a transient such as the R wave of the electrocardiogram, which introduces a signal on the recording paper and a simultaneous movement of a “flag” in the cinefluorographic field. Mudd and Loeffel’ in 1960 developed a method for imprinting a physiologic event on Light from a onethe cinefluorographic film. inch oscilloscope, which carried a signal representing a physiologic event, exposed the cinefluorographic film. Although the spot on the oscilloscope could be reproduced on the film, the physiologic trace had insufficient definition
D
* From the Cardiovascular Laboratory, Department of Medicine, Duke University School of Medicine, Durham, N. C. This project was supported in part by Grant HE-07563 of the National Heart Institute of the National Institutes of Health. i Electronics for Medicine, White Plains, N. T.
668
THE
AMERICANJOURNAL
OF CARDIOLOGY
Recording
Eight
Physiologic
Events
669
Cinc-Tmce Control
FIG. 1.
Schematic drawing of the tine-trace system. The output of the Electronics for Medicine DR-8 Recorder passes through the control unit to the storage cathode ray oscilloscope and is directed into the magazine and onto the base side of the film,
FIG. 3. Modified 35 mm. magazine for tine-trace unit. The mechanical shutter (A) fits over the prism (C), which deflects the light which has passed through the lens (B) onto the base side of the film.
FIG. 2. Photograph of Picker one-inch image intens@ with 35 mm. camera and specially modified magazine (B) to which is attached box (A) which houses the storage cathode ray oscilloscope. FIG.
spot, the persistent image was not recorded, and the traces gave a “bouncing ball” effect. An image storage tube with a P20 phosphor was therefore selected. This tube shows no decay VOLUME
15,
MAY
1965
n’ne
Diagram of the storage cathode ray oscilloscope magasystem. The light from the oscilloscope (F) is
4.
focused by a lens (E) and directed by a prism (C) in the magazine (D) onto the base side of the film (B). The emulsion side of the film is exposed by light from the output phosphor (A).
670
McIntosh,
FIG. 5.
Four
Scheiner
and Whalen
successiw frames (60/set.) from a patient with a (:oronary
of the stored image. It was also necessary to develop a method to accomplish fast and complete erasure of the image. With the present device, a very high brightness of the screen is possible (over 1,000 foot-lamberts), and erasure can be accomplished in 50 msec. DESCRIPTION 01; APPARAT~JS The apparatus is schematized in Figure 1. The physiologic information obser\ved on the oscilloscope screen of the Electronics for Medicine DR-8 recorder is directed through an amplifier to a slave oscilloscope mounted beside the 35 mm. cinefluorographic magazine, which is recording the cinefluorographic event (Fig. 2). The magazine has been modified with a lens and mechanical shutter system* (Fig. 3). shutter system has recently been *The mechanical replaced by an electronic shut&r system which brightens the trace for 5 msec. during each frame. This technic requires a contact available from the camera to trigger the brightening but eliminates the mechanical complexity of the shutter and also gives uniform exposure at any frame rate, since the traces are exposed for only 5 msec. regardless of the exposure time from the x-ray image.
arteriovenous fistula. See text.
The light beam “carrying” the physiologic data from the slaved oscilloscope is deflected by a prism through the lens on the side of the magazine to the lower right corner of the nonemulsion side of the cinefluorographic film (Fig. 4). Thus, anatomic events derived from the image intensifier can be recorded on the emulsion side of the 35 mm. film while physiologic traces derived from the DR-8 recorder can be simultaneously imposed on the nonemulsion side of the same cinefluorographic frame. Because of the very high output of light from the storage cathode ray tube, it is possible to expose the film through the base including the anti-halation backing. By using this rear approach, no beam splitters or other optical elements need be inserted in the optical path of the image intensifier. Therefore, the recording of the physiologic traces has no effect on the exposure and density of the x-ray image. The recording area occupies 7 per cent of the exposed cinefluorographic frame. The traces may sweep this area in either 3 or 6 sec. The tracings are superimposed over the THE
AMERICAN
JOURNAL
OF
CARDIOLOGY
Recording
FIG. 6. Four
Eight
APPLICATIONS
OF
THE METHOD
The applications of the unit are numerous. Figure 5 shows the simultaneous recording of an opacified coronary arteriovenous fistula and the electrocardiogram, pulmonary artery pressure and right atria1 pressure. Figure 6 shows the recording of the electrocardiogram, pneumo-
15,
MAY 1965
671
Events
successive frames (bO/sec.) from a patient with constrictive pericarditis.
anatomic structures recorded on the cinefluorogram; therefore, the anatomic information in The this area of the cinefluorogram is not lost. relative position of the traces within this area is identical with the location on the oscilloscope of the DR-8 recorder. The location of the individual traces can be moved within the recording area by t!le centering control button on the DR-8 recorder. Erasing of the image is accomplished within three frames at 60 frames/ sec. Therefore, at a sweep speed of 3 sec. and a film speed of 60 frames/set., the recording area of 3 frames is blanked out every 180 frames.
VOLUME
Physiologic
See text.
tachogram, intracardiac phonocardiogram, and right ventricular pressure recorded by a transducer-tipped catheter in a patient with constrictive pericarditis. SUMMARY
A system has been devised whereby the physiologic data available on the oscilloscope of the Electronics for Medicine DR-8 recorder can be superimposed on a 35 mm. cinefluorographic film at filming speeds of 60 frames/set. Selected applications of such a technic are presented. REFERENCES 1. MUDD, J. G. and I_OEFFEL, B. A simple method for recording EKG, phonocardiogram, or pressure IRE Tr. Biomed. tracing on the cineangiogram.
Electronics, 7 : 228, 1960. 2. MCINTOSH, H. D., WHALEN, R. E. and BARRY, W. F. The role of cinefluorography in clinical cardiology: Present and future. Am. Heart J., 68: 12, 1964.
for Recording
Events
Eight
Physiologic
on the Cinefluorogram*
HENRY D. MCINTOSH,M.D.,
MARTIN
L. SCHEINER,
Durham,
North
B.E.E.~
and ROBERT E. WHALEN,
M.D.
Carolina
to permit analysis. These workers, therefore, abandoned this approach in favor of a system whereby light reflected from the moving stylus of a standard electrocardiographic machine was used to expose the cinefluorographic film. A telescopic lens and right-angle mirror system directed the light from the output phosphor of the image intensifier tube. The definition of the trace and the detail of the single frame of 16 mm. film was said to be inadequate for detailed analysis, but it did afford a point of reference for timing. A tine-trace unit developed for our laboratory permits the data recorded by any or all of the eight channels of an Electronics for Medicine DR-8 recorder to be simultaneously recorded with the image from the output phosphor of an image intensifier on individual frames of 35 mm. This is accomplished cinefluorographic film.* by utilizing the output of the DR-8 recorder to drive a specially designed slave oscilloscope. Initially the choice of an appropriate tube for the slave oscilloscope presented problems. Standard long persistence phosphors were re,jected after a number of experiments. Regardless of the phosphor or the amount of voltage used, all suffered from the same defect: With a light level sufficient to produce an image of sufficient persistence for a second or two, the intensity of the initial spot was so high as to greatly overexpose the film and make difficult the recognition of the moment in time represented by the particular frame. When the light level was set to give reasonable exposures for the initial
URING the last decade technics for documenting rapidly changing mechanical and electrical physiologic events with photographic recorders have been greatly improved. Similar advances have been made in recording the functional anatomy by means of cinefluorography. It would naturally follow that the clinical physiologist would attempt to utilize both technics simultaneously to correlate physiologic with anatomic changes. To accomplish such a correlation, it is necessary either (1) to identify the physiologic event (recorded on paper) that occurs coincident with specific anatomic changes recorded on an individual cinefluorographic frame, or (2) to simultaneously, the cinefluorographic expose film to both a light beam containing the physiologic data and the light beam from the image intensifier containing the anatomic information. The first method has been used in a number of laboratories. This method utilizes a capacitor, discharged by a transient such as the R wave of the electrocardiogram, which introduces a signal on the recording paper and a simultaneous movement of a “flag” in the cinefluorographic field. Mudd and Loeffel’ in 1960 developed a method for imprinting a physiologic event on Light from a onethe cinefluorographic film. inch oscilloscope, which carried a signal representing a physiologic event, exposed the cinefluorographic film. Although the spot on the oscilloscope could be reproduced on the film, the physiologic trace had insufficient definition
D
* From the Cardiovascular Laboratory, Department of Medicine, Duke University School of Medicine, Durham, N. C. This project was supported in part by Grant HE-07563 of the National Heart Institute of the National Institutes of Health. i Electronics for Medicine, White Plains, N. T.
668
THE
AMERICANJOURNAL
OF CARDIOLOGY
Recording
Eight
Physiologic
Events
669
Cinc-Tmce Control
FIG. 1.
Schematic drawing of the tine-trace system. The output of the Electronics for Medicine DR-8 Recorder passes through the control unit to the storage cathode ray oscilloscope and is directed into the magazine and onto the base side of the film,
FIG. 3. Modified 35 mm. magazine for tine-trace unit. The mechanical shutter (A) fits over the prism (C), which deflects the light which has passed through the lens (B) onto the base side of the film.
FIG. 2. Photograph of Picker one-inch image intens@ with 35 mm. camera and specially modified magazine (B) to which is attached box (A) which houses the storage cathode ray oscilloscope. FIG.
spot, the persistent image was not recorded, and the traces gave a “bouncing ball” effect. An image storage tube with a P20 phosphor was therefore selected. This tube shows no decay VOLUME
15,
MAY
1965
n’ne
Diagram of the storage cathode ray oscilloscope magasystem. The light from the oscilloscope (F) is
4.
focused by a lens (E) and directed by a prism (C) in the magazine (D) onto the base side of the film (B). The emulsion side of the film is exposed by light from the output phosphor (A).
670
McIntosh,
FIG. 5.
Four
Scheiner
and Whalen
successiw frames (60/set.) from a patient with a (:oronary
of the stored image. It was also necessary to develop a method to accomplish fast and complete erasure of the image. With the present device, a very high brightness of the screen is possible (over 1,000 foot-lamberts), and erasure can be accomplished in 50 msec. DESCRIPTION 01; APPARAT~JS The apparatus is schematized in Figure 1. The physiologic information obser\ved on the oscilloscope screen of the Electronics for Medicine DR-8 recorder is directed through an amplifier to a slave oscilloscope mounted beside the 35 mm. cinefluorographic magazine, which is recording the cinefluorographic event (Fig. 2). The magazine has been modified with a lens and mechanical shutter system* (Fig. 3). shutter system has recently been *The mechanical replaced by an electronic shut&r system which brightens the trace for 5 msec. during each frame. This technic requires a contact available from the camera to trigger the brightening but eliminates the mechanical complexity of the shutter and also gives uniform exposure at any frame rate, since the traces are exposed for only 5 msec. regardless of the exposure time from the x-ray image.
arteriovenous fistula. See text.
The light beam “carrying” the physiologic data from the slaved oscilloscope is deflected by a prism through the lens on the side of the magazine to the lower right corner of the nonemulsion side of the cinefluorographic film (Fig. 4). Thus, anatomic events derived from the image intensifier can be recorded on the emulsion side of the 35 mm. film while physiologic traces derived from the DR-8 recorder can be simultaneously imposed on the nonemulsion side of the same cinefluorographic frame. Because of the very high output of light from the storage cathode ray tube, it is possible to expose the film through the base including the anti-halation backing. By using this rear approach, no beam splitters or other optical elements need be inserted in the optical path of the image intensifier. Therefore, the recording of the physiologic traces has no effect on the exposure and density of the x-ray image. The recording area occupies 7 per cent of the exposed cinefluorographic frame. The traces may sweep this area in either 3 or 6 sec. The tracings are superimposed over the THE
AMERICAN
JOURNAL
OF
CARDIOLOGY
Recording
FIG. 6. Four
Eight
APPLICATIONS
OF
THE METHOD
The applications of the unit are numerous. Figure 5 shows the simultaneous recording of an opacified coronary arteriovenous fistula and the electrocardiogram, pulmonary artery pressure and right atria1 pressure. Figure 6 shows the recording of the electrocardiogram, pneumo-
15,
MAY 1965
671
Events
successive frames (bO/sec.) from a patient with constrictive pericarditis.
anatomic structures recorded on the cinefluorogram; therefore, the anatomic information in The this area of the cinefluorogram is not lost. relative position of the traces within this area is identical with the location on the oscilloscope of the DR-8 recorder. The location of the individual traces can be moved within the recording area by t!le centering control button on the DR-8 recorder. Erasing of the image is accomplished within three frames at 60 frames/ sec. Therefore, at a sweep speed of 3 sec. and a film speed of 60 frames/set., the recording area of 3 frames is blanked out every 180 frames.
VOLUME
Physiologic
See text.
tachogram, intracardiac phonocardiogram, and right ventricular pressure recorded by a transducer-tipped catheter in a patient with constrictive pericarditis. SUMMARY
A system has been devised whereby the physiologic data available on the oscilloscope of the Electronics for Medicine DR-8 recorder can be superimposed on a 35 mm. cinefluorographic film at filming speeds of 60 frames/set. Selected applications of such a technic are presented. REFERENCES 1. MUDD, J. G. and I_OEFFEL, B. A simple method for recording EKG, phonocardiogram, or pressure IRE Tr. Biomed. tracing on the cineangiogram.
Electronics, 7 : 228, 1960. 2. MCINTOSH, H. D., WHALEN, R. E. and BARRY, W. F. The role of cinefluorography in clinical cardiology: Present and future. Am. Heart J., 68: 12, 1964.