US3491749A - Apparatus for use in the preparation of x-ray photographs of blood vessels - Google Patents

Description

AKE SAMUEL GIDLUND APPARATUS FOR USE IN THE PREPARATION OF X 3,491,749 -RAY Jan. 27, 1970 PHOTOGRAPHS OF BLOOD VESSELS Filed NOV. 12, 1965 IENVENTOR. AKE SAMUEL GIDLUND United States Patent 3,491 749 APPARATUS FOR USE IN THE PREPARATION OF X-RAY PHOTOGRAPHS OF BLOOD VESSELS Ake Samuel Gidlund, Lokevagen 13B, Djursholm, Sweden Filed Nov. 12, 1965, Ser. No. 507,440 Claims priority, application Sweden, Nov. 12, 1964, 13,612/ 64 Int. Cl. A61b /02; A61m 5/00 U.S. Cl. 1282.05 5 Claims ABSTRACT OF THE DISCLOSURE An apparatus is provided for employing a contrast agent to prepare blood vessels for X-ray photography.

The contrast agent is injected into the blood vessels to be The present invention relates to an apparatus for use in the preparation of X-ray photographs of blood vessels.

Currently X-ray contrast agents, used in X-ray photography of blood vessels in the heart or the kidneys for example, are injected or delivered to the blood vessels in a single massive dosage. Thereafter, the X-ray photograph is completed by conventional X-ray techniques. By injecting comparatively large quantities of a contrast agent, the X-ray photographs of some of the blood vessels, whether healthy or diseased, are so filled with the contrast agent that they are of little or no prognostic value to a physician or technician. In addition tissues and even portions of organs may be torn when a sudden surging of a large dosage of a contrast agent is injected through blood vessels, such as for example valves of the heart which are susceptible to being damaged.

It has been determined that blood will flow more readily th ough healthy blood vessels than diseased blood vessels. Thus, any contrast agent injected into blood vessels will remain for a longer time period in diseased blood vessels than in those adjacent blood vessels which are healthy.

The present invention overcomes the prior art disadvantages by controlling the quantity of contrast agent injected into the diseased blood vessels to be photographed in relation to the blood flow rate through these blood vessels. Preferably by injecting in a predetermined requence, small separate dosages of a contrast agent, the proper level of contrast agent for X-ray photography in the diseased blood vessels will be reached. To insure that a proper diagnostic X-ray photograph is taken, X-ray photographs may be continuously taken during the entire injection process.

The apparatus in accordance with the invention comprises injection means which when actuated deliver a quantity of a contrast agent to the blood vessels to be X-rayed and programing means for controlling the actuation of the injection means in a predetermined sequence, thereby controlling the quantity of contrast agent injected.

Features and advantages of the invention will be obtained from a reading of the fol owing description taken in conjunction with the accompanying drawing, which is a schematic illustration of an apparatus for use in the preparation of X-ray photographs.

The drawing illustrates, as an exemplary embodiment of the invention, an apparatus which comprises a syringe "ice 1 provided with a cavity 40 accommodating a piston 6, which is axially displaceable by a piston rod 5. The upper or delivery end 41 of the syringe 1 is engaged by a rubber delivery tube 2 which is in communication with a catheter (not shown). An upward move or thrust of the piston 6 causes a contrast agent, disposed within the confines of the syringe cavity 40, to be injected into the catheter through the tube 2. The catheter, which delivers the contrast agent to the blood vessels to be X-rayed, is of course well known and need not be described here. The syringe cavity 40 is connected to a conventional filling device (not shown) which is adapted to fill the cavity with a desired contrast agent after an injection cycle.

Clamping means disposed adjacent the tube 2 are pro vided to move between open and closed positions; in the open position a dosage of contrast agent may be injected, while in the closed position it may not. The clamping means are depicted as two elements, a fixed element 3 and a movable element 4; a compression spring 44 which urges the element 4 into closed clamping relation with the tube 2; and a coil 45 and its associated circuit which when energized overcomes the force exerted by the compression spring 44 and moves the element 4 downward opening the clamping means.

Remote from the piston 6, the rod 5 is connected to a piston 7 which is axially displaceable within a bore 47 formed by an air cylinder 8. When air under pressure is delivered from a tank 19 through a line 15b to the bore 47 of the cylinder 8, it acts upon the piston 7 to drive it and the piston 6 upwardly effecting a contrast agent discharge through the tube 2. At this time the clamping means will, of course, be opened. To move both the pistons 6 and 7 downward after a completed injection cycle, a lead screw 11 is manually rotated by means of a handle 49. The screw 11, operatively engaging a lever 10 which is fixed to the rod 5, upon rotation moves the lever 10 downward, and thereby translates the pistons 6 and 7 to their bottom positions 'wherein the piston 7 will be adjacent but spaced from the bottom 12 of the cylinder 8, and the piston 6 will be adjacent the bottom of the syringe 1. A pin mechanism 50 is adapted to disconnect the lever 10 from the screw 11 when the piston rod 5 is to be moved upwardly during an injection cycle. Thus the screw 11 will not impede-the upward movement of the piston 6.

During a downward move of the rod 5, a lever 9 fixed to the rod 5, is connected at its free end to a spiral-shaped shaft 13 and when moved by the rod 5 rotates the shaft 13 causing an appended programming disc 14 to be rotated therewith. The shaft 13 is rotatably mounted in suitable bearing members 52 and 53. After an injection cycle the rod 5, being moved downward by the lead screw 11, causes the lever 9 to rotate the programming disc 14 to a reset position wherein it awaits the following injection cycle.

The disc 14 is secured to the shaft 13 by means of a latching mechanism and may be readily removed therefrom and another programming disc inserted in its stead. The programming disc 14 functions to control the sequencing of a supply of compressed air delivered to the cylinder 8 and the operation of the clamping elements 3 and 4. About the periphery of the disc 14, a series of recesses 30 and 31 have been formed. A follower member 32, in the form on an elongated arm or lever, is resiliently urged into engagement with the periphery of the disc 14 so that upon rotation of the disc 14, at intervals depending upon the spacing between the recesses 30 and 31, it will be received within successive recesses 30 and 31. When the member 32 is disposed within a recess, it actuates a switch 33 having contacts 33 (A and B).

Contacts 33-A are normally closed but open when the switch 33 is actuated to de-energize the coil 45, permitting the spring 44 to drive the element 4 to a position where it clamps the tube 2 between the elements 3 and 4. Contacts 33B also close at this time and energize a timing circuit T, which may include a standard make and break relay, adapted to open contacts T-1 for some preselected time interval. When the contacts T-l open they open a circuit to a coil 55 permitting a compression spring 56 to move a valve 16 to close off communication between the pressure tank 19 and the cylinder 8. After the selected time interval, which preferably may be varied within a range of from about 0.08 to 2 seconds, the contacts T-l close, energizing the coil 55 opening the valve 16. Thereafter, pressure is again applied to the piston 7 which moves upwardly. The upward movement of the lever 9 rotates the disc 14 causing the member 32 to leave the recess and open the switch 33, closing contacts 33A and opening contacts 33B. The coil 45 being energized then opens the clamping means.

A valve 17 provides the means for initiating the operation of an injection cycle. The valve 17 is adapted to open and close communication between the cylinder 8 and the source of pressure 19. To accomplish this function, the valve 17 is provided with a cam follower roller 26 which is resiliently urged into engagement with a rotatable cam 27. The cam 27 is keyed to a shaft 58 which may be drivenby a speed motor M or rotated manually by means of a crank. The basic function of the cam 27 is to open the valve 17 during an injection cycle and to close it after completion of the cycle. Therefore, the motor M could, for example, be energized by the engagement of the arm 32 with a recess in the disc 14 energizing a circuit at the end of an injection cycle. The circuit then would energize the motor M to rotate the cam 27 to a position 'where it closes the valve 17. By rotating the cam 27 to its operative position, the valve 17 opens providing communication betwene the tank 19 and the cylinder 8. At this time the shaft 58 closes a set of contacts 26-A in series with the coil 45 operating the clamping elements 3 and 4. When closed, the valve 17 opens an exhaust port 60 in the line 1517 which permits the downward movement of the piston 7, caused by the lead screw 11, to exhaust air from the bore 47 of the cylinder 8, while closing off communication between the tank 19 and the cylinder 8.

The pressure supplied to the cylinder 8 from the compressed air tank 19 is by means of the line 15a delivered up to the valve 17. A valve 18, disposed within the line 15a, is manually set to vary the pressure delivered to the line 15a which is measured by a pressure gauge 20. A manually actuated exhaust valve 28, also located in line 15a, allows an operator to quickly bypass pressure in the line 15a to the atmosphere. The line 15:: branches in its path to the valve 17 into two separate lines 21 and 24. Line 24 leads to a conventional pressure regulator 25, arranged to control the valve 16, interposed in the line 15b, between the cylinder 8 and the valve 17. When the pressure in the line 15a rises above some predetermined value, the regulator 25 opens normally closed contacts 25-A deenergizing the coil 55, thereby permitting the compression spring to close the valve 16. A low pressure limit control in the regulator 25 could also have been provided to open the contacts 25-A.

The line 21 leads to a pressure modulator 22 formed by a housing having a conical chamber 23 which is filled with a compressible material, for example balls of varying sizes formed of a synthetic material. Preferably, some of the balls will have different moduli of elasticity. The pressure modulator 22 is provided to prevent any sudden surges of air into the cylinder 8, and thereby reduces the possibility of damage to any of the internal organs by damping the initial rate of flow of the contrast agent through the tube 2. More particularly by providing modulator 22 between the tank 19 and the cylinder 8, the initial gas pressure provided to the line 15b will be considerably reduced, preventing an exaggerated movement of the piston 6, which in turn, reduces the pressure in the tube 2 minimizing possible damage to the tissue during the initial flow of contrast agent.

The first step of utilizing the apparatus after engaging the pin mechanism 50 is to rotate the handle 49 thereby moving the piston 7 downwardly towards the bottom of the cylinder 8. The air disposed within the bore of the cylinder 8 below the piston 7 is exhausted out through the line 15b by means of the port 60 opened by the valve 17. A contrast agent is now filled into the syringe cavity.

During the downward movement of the piston rod 5, the program disc 14 will have been returned to a position wherein it is ready for the next injection cycle. The pressure within the tank 19 is now observed by means of a gauge 62. Then the pressure in the line 15a as measured by the gauge 20 is adjusted.

The coil 45 at this time is de-energized, inasmuch as the contacts 26-A are open, and therefore the compression spring 44 will have closed the clamping elements 3 and 4 preventing communication between the catheter and the syringe cavity 40. To commence an injection cycle, the cam 27 is rotated to a position where it opens the valve 17 and the communication between the line 15a and the line 15b and at the same time closes the exhaust port 60. This action results in providing a source of pressurized air to the bore 47 of the cylinder 8 which bears against the piston 7.

Coincidentally with the opening of the valve 17, the cam 27 closes the set of contacts 26-A in series with the coil 45 of the clamping elements 3 and 4. The contacts 26-A will remain closed during the injection cycle and preferably will open sometime after the completion of the injection cycle. Upward movement of the cylinders 6 and 7 is now effected. The lever 9, being driven upwardly by the rod 5, rotates the spiral shaft 13 and its appended disc 14. When one of the recesses 30 or 31 is engaged by the lever 32, the member 32 actuates both the contacts 33-A and B. The contacts 33-A open de-energizing the coil 45, which permits the spring 44 to close the elements 3 and 4, while the contacts 33-B close and energize the circuit T which opens its contacts T-l causing the valve 16 to close. The contacts T-l, in series with the coil, are adapted to remain closed only for a short interval and thereafter open. When the valve 16 opens pressurized air is delivered to the cylinder 8, rotating the disc 14 so that the member 32 thereafter is engaged by the raised portion of the periphery of the disc 14. The member 32 then disengages from the switch 33 returnning the contacts 33-A and B to their normal positions.

The peripheral length of disc segments between successive recesses 30 and 31, assuming that other parameters are maintained, such as the pressure in line 15b, will determine the quantity of each dosage. The time interval between the injection of dosages, adjusted by means of the circuit T should preferably be a constant. Furthermore, it has been found most preferable to limit it to a range of from about 0.08 to 2 seconds.

It will be understood that the number of dosages and the time interval between the injection of successive dosages of a contrast agent should be varied in relation to the rate of flow of blood through the blood vessels to be X-ray photographed in order that an appropriate level of contrast agent is in the blood vessels when the X-ray photograph is taken. To insure however that at least one proper diagnostic X-ray photograph is taken, it has been shown advisable to have a continuous process of photog raphy during the entire injection cycle. Twelve pictures or frames per second has been found to be an effective speed or rate of X-ray photography. The picture speed should, however, be somewhat higher than 12 frames per second when the heart is to be X-rayed because of the high blood flow rate through the blood vessels of the heart.

If for example five separate dosages of contrast agent are to be applied in a time sequence with one folllowing the other, there may be five recesses 30 and 31 cut into the periphery of the disc 14. The quantity of each dosage should preferably be varied and illustratively could take the following respective dosage quantities: 7, 3, 2, 8, and 4 milliliters of contrast agent. Also, it has been determined that no more than about 15 milliliters of contrast agent should be injected for any given dosage.

I claim:

1. An apparatus for injecting a contrast agent for use in the preparation of X-ray photographs of blood vessels, comprising injection means defining a contrast agent receiving cavity, discharge means connected to the cavity and adapted to be placed in communication with the blood vessels to be photographed, clamping means disposed adjacent the discharge means and movable between open and closed positions to prevent the flow of contrast agent from the cavity through the discharge means in the closed position and to permit an injection flow in the opened position, first piston means disposed within the cavity and movable when actuated to inject contrast agent from the cavity through the discharge means, and programing means for actuating the first piston at preselected intervals, the programing means being operatively connected to said clamping means to move the clamping means to the open position during the interval when the first piston is actuated.

2. An apparatus according to claim 1 wherein the programming means includes an air cylinder having a second piston disposed therein, a piston rod affixed to the first and the second pistons, a source of compressed air, valve means in communication with the pressure source and movable between open and closed positions, the valve means in an open position permitting delivery of a flow of pressurized air to the cylinder thereby moving the second piston to cause a discharge of the contrast agent and in a closed position preventing a flow of pressurized air to the cylinder.

3. An apparatus according to claim 2 wherein the programming means includes a programming disc actuated by the movement of the piston rod, and electrical 'means actuated by the disc in a predetermined sequence for opening both the clamping means and the valve means at predetermined intervals to discharge a dosage of contrast agent through the discharge means.

4. An apparatus according to claim 3 including pressure modulator means for preventing initial sudden surges of pressurized air into the cylinder, thereby modulating the flow of contrast agent through the discharge means.

5. An apparatus according to claim 4 wherein the modulator means includes a housing having a conically shaped interior which accommodates a plurality of elastic elements of varying size and modulus of elasticity.

References Cited UNITED STATES PATENTS 2,039,000 4/1936 Hesse l28-2.05 2,602,446 7/1952 Glass et al. 128-218 3,155,090 11/1964 Holter 128--2 3,156,236 11/1964 Williamson 128-2.05 3,313,291 4/1967 Marshall 1282 3,335,724 8/1967 Gienapp 128-218 RICHARD A. GAUDET, Primary Examiner K. L. HOWELL, Assistant Examiner U.S. Cl. X.R. 128-218

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