U.S. patent application number 17/534114 was filed with the patent office on 2022-05-26 for ultrasonically detectable intrauterine system and method for enhancing ultrasound detection.
The applicant listed for this patent is Bayer OY. Invention is credited to Sara HEINONEN, Taina TJAEDER.
Application Number | 20220160538 17/534114 |
Document ID | / |
Family ID | 1000006125034 |
Filed Date | 2022-05-26 |
United States Patent
Application |
20220160538 |
Kind Code |
A1 |
TJAEDER; Taina ; et
al. |
May 26, 2022 |
ULTRASONICALLY DETECTABLE INTRAUTERINE SYSTEM AND METHOD FOR
ENHANCING ULTRASOUND DETECTION
Abstract
The present invention relates to ultrasonically detectable
intrauterine systems and to a method for enhancing ultra-sound
detection of these systems. An intrauterine sys-tem having an inert
metal coating on at least part of the body of the intrauterine
system or at least one inert metal clip, pin, ring or sleeve
fixedly positioned on the body of the intrauterine system is
described.
Inventors: |
TJAEDER; Taina;
(Piispanristi, FI) ; HEINONEN; Sara; (Turku,
FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bayer OY |
Turku |
|
FI |
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|
Family ID: |
1000006125034 |
Appl. No.: |
17/534114 |
Filed: |
November 23, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14569616 |
Dec 12, 2014 |
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17534114 |
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11887901 |
May 15, 2008 |
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PCT/FI2006/050123 |
Apr 4, 2006 |
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14569616 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 8/0841 20130101;
A61M 31/002 20130101; A61B 8/481 20130101; A61F 6/144 20130101 |
International
Class: |
A61F 6/14 20060101
A61F006/14; A61B 8/08 20060101 A61B008/08; A61M 31/00 20060101
A61M031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2005 |
FI |
20050345 |
Claims
1. An ultrasonically detectable intrauterine system (IUS) for
long-term insertion into a uterine cavity comprising: a vertical
arm having an upper end and a lower end, horizontal arms extending
from the upper end of the vertical arm, a medicated capsule mounted
on the vertical arm, and at least one image enhancing structure
adapted to improve ultrasound imaging of the IUS; wherein the at
least one image enhancing structure comprises at least one metal
ring positioned at an upper end or lower end of the vertical arm,
or at an end of one of the horizontal arms, wherein the at least
one metal ring is composed of silver, gold, titanium, tungsten,
bismuth, platinum, palladium, or a combination thereof.
2. The IUS according to claim 1, further comprising at least two
locking structures to keep the medicated capsule in correct
position during insertion, use and removal of the IUS.
3. The IUS of claim 1, wherein the medicated capsule is a
hormone-elastomer capsule that regulates a release of
levonorgestrel.
4. The IUS of claim 1, wherein the at east one metal ring is
composed of a silver wire.
5. The IUS of claim 1, wherein the at least one metal ring is
partially embedded within the vertical arm or horizontal arm.
6. The IUS of claim 1, wherein the at least one metal ring
comprises a double ring that surrounds the upper end of the
vertical arm.
7. The IUS of claim 6, wherein the double ring is partially
embedded within the upper end of the vertical arm.
8. The IUS of claim 1, wherein the at least one metal ring does not
comprise an active ingredient.
9. The IUS of claim 1, wherein the IUS is a hormonal device, and
the medicated capsule comprises the only active hormonal
ingredient.
10. An ultrasonically detectable intrauterine system (IUS) for
long-term insertion into a uterine cavity, said IUS comprising a
T-shaped plastic body and a hormone capsule placed in the vertical
arm of the T-shaped plastic body, the vertical arm comprising at
its lower end a loop wherein removal threads are tied,
characterized in that the IUS comprises at least one image
enhancing structure for improving the ultrasound imaging of the
EUS, wherein the at least one image enhancing structure is at least
one silver ring fixedly positioned and at least partly embedded in
the body of the IUS.
11. The IUS of claim 10, wherein the hormone capsule regulates a
release of levonorgestrel.
12. The IUS of claim 10, wherein the at least one silver ring does
not comprise an active ingredient.
13. The IUS of claim 10, wherein the hormone capsule comprises the
only active hormonal ingredient.
14. A method of improving the visualization of an intrauterine
system within the uterine cavity in an ultrasound examination
comprising providing the IUS according to claim 1, and inserting
the IUS into the uterine cavity and examining the position of the
IUS within the uterine cavity in the ultrasound examination.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 14/569,616, filed on 12 Dec. 2014, which is a Continuation of
U.S. application Ser. No. 11/887,901, filed on 15 May 2008, which
is a National Stage entry of International Application No.
PCT/FI2006/050123, filed 4 Apr. 2006, which claims priority to
Finland Application No. 20050345, filed 5 Apr. 2005, the content of
each of these applications is herein incorporated by reference in
their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to ultrasonically detectable
intrauterine systems and to a method for enhancing ultrasound
detection of these systems.
BACKGROUND OF THE INVENTION
[0003] The intrauterine systems, commonly known as IUS's, have long
been known and they have been constructed in numerous shapes and
sizes and of various materials. The IUS's consist normally of a
plastic frame having the shape of the letter T or 7, although the
shapes of letters S and .omega. are also possible. The IUS's which
contain drugs can be used to administer these drugs locally to the
uterus at a controlled re-lease rate over a prolonged period of
time. The medicated IUS's which have found considerable acceptance
in contraception and hormonal treatment can be divided into copper
and hormonal devices. In a copper IUD (Intra Uterine Device), a
copper wire or silver cored copper wire is wound around the
vertical stem of the frame whereas in a hormonal IUS a hormone
containing elastomeric capsule is placed on the vertical stem. The
capsule may be coated by an elastomer or polymer membrane which
controls drug release from the elastomer-hormone capsule.
Monofilament removal threads, used for IUS removal after the period
of use, are tied to the loop at the end of the vertical stem.
[0004] Undesirable complications that have been associated with the
use of IUS's are infec-tion, bleeding, uterine perforation,
cervical laceration, septic abortion, ectopic preg-nancy, and
expulsion of the IUS. Expulsion is undesirable, because the IUS can
no longer provide protection against pregnancy. Perhaps the most
common side effect of copper IUD's is abnormal bleeding, taking the
form of menorrhagia, metrorrhagia, or both. This side effect is not
found with hormonal IUS's, which can be actually used for the
treatment of menorrhagia. A disparity between the size and/or shape
of the uterine cavity and the IUS and inaccurate (non-fundal)
placement of the system at the time of insertion have both been
linked to IUS-induced increases in uterine bleeding.
[0005] In addition to the optimal design and composition, it is
important that the IUS is placed in a proper position. For many
complications, the examining physician must be able to detect the
positioning and placement of the IUS in order to diagnose the
problem, and to prevent further complications.
[0006] Currently, there are several techniques for determining the
presence and position of IUS's in the uterus. One technique
involves the use of X-rays. However, the use of X-rays in the area
of uterus and ovaries should be avoided whenever possible. Another
detection technique involves the use of sounds. Physicians also
will often examine the marker strings, which are attached to the
IUS to detect the presence and position of the IUS and at the end
of usage time to remove the system. Another technique is to
manipulate the uterus under fluoroscopic examination. In some
cases, a second IUS has been inserted into the uterus to serve as
an intra-uterine marker to detect relative placement of the lost
IUS.
[0007] Ultrasound imaging is widely used in medical applications to
non-invasively observe the structures within the human body. In
addition to imaging physiological structures and tissue, ultrasound
imaging has also been employed to image medical devices that are
inserted into tissue or passageways of the patient.
[0008] The uterus is visible to ultrasound by reconciling the
position of the IUS with the position of the uterus. In reconciling
the relative positions of the uterus and IUS, the examining health
care personnel can determine whether the IUS is properly placed
within the uterus. The medical personnel will be able to determine
whether the IUS has perforated the uterus or cervix. If the IUS has
partially or fully perforated the uterus or cervix, the physician,
by knowing the position of the IUS is better able to plan an
appropriate strategy for removal of the IUS.
[0009] In a typical imaging system, short bursts of ultrasound
energy are directed into a patient's body with a transducer. The
returning reflected ultrasound energy, or echoes, are received by
the same transducer and are converted to electrical signals. The
signals representing the reflected energy are processed and
formatted into a video image of a target region. The technology is
especially valuable for medical imaging applications because
diagnostic ultrasound procedures are safe, very acceptable to
patients and less expensive than other digital imaging
technologies. Also, instruments are widely available and images are
produced in real time.
[0010] Most medical devices have acoustic impedance similar to that
of the tissue into which the device is inserted. Consequently,
visibility of the device is poor and accurate placement becomes
extremely difficult if not impossible. Another problem affecting
the visibility of devices is the scattering angle. For example,
stainless steel needles have acoustic impedance significantly
different from tissue and are highly visible under ultrasound
imaging when the needle is in the plane of the ultrasound beam. If
the needle is moved to some other angle off-axis, the ultrasound
beam is scattered in a direction other than the transducer and the
needle becomes less visible or even invisible under ultrasound
imaging.
[0011] Both of the problems described above have been addressed by
efforts to increase the scattering power of the device so that the
device becomes visible even when it is not completely in the plane
of the ultrasound beam. Various approaches have also been used to
enhance ultrasonic imaging by modifying the reflective surface
characteristics of these devices. A variety of ultrasound contrast
agents are known, including porous uniformly sized non-aggregated
particles. Contrast agents may enhance the visibility of target
tissue into which they are injected, but they can not enhance the
ultrasound visibility of insertable medical devices.
[0012] U.S. Pat. No. 5,201,314 describes a medical device that is
insertable into tissue or a passageway and imageable with sonic
imaging equipment. The device includes an elongated insertable
member that has an interface having a shape that is responsive to
the sonic beam for producing the image. The elongated member
includes a substance such as spherically or other
geometrically-shaped particles that have a predetermined contour
for establishing the interface. This contoured substance is
contained within the material of the elongated member or
alternatively or in combination attached to or embedded in the
outside surface of the member material. In one embodiment, the
interface layer may include a high density metal such as titanium,
tungsten, barium, bismuth, platinum, silver, gold, or
palladium.
[0013] U.S. Pat. No. 6,306,125 relates to a system for delivering
an implant to tissue to be treated. To enhance the visibility of
the implant to imaging systems, echogenic contrast agent can be
added to the implant. Alternatively an implant can contain
elements, molecules, compounds or compositions, which have atomic
weights sufficient to confer radiopacity to the implant.
Particularly preferred radiopaque materials are, e.g. barium, gold,
platinum, tantalum, bismuth and iodine. The radiopacifying agents
can be incorporated into the implants in several ways.
Biocompatible non-immunogenic metals such as gold and platinum may
be incorporated as a very fine dispersion with particle sizes less
than a few micrometers. Other heavy atoms may be incorporated in
the form of inorganic salts, such as barium sulphate.
[0014] Several efforts have been made to enhance the echogenicity
of medical device by modifying the surface of the device. U.S. Pat.
No. 4,869,259 relates to the enhanced echogenicity of the needle by
particle blasting with 50-micron particles to produce a uniformly
roughened surface. U.S. Pat. No. 4,977,897 relates to sounding
apertures machined into needles to match the incident beam
wavelength this improving sonographic visibility. U.S. Pat. No.
5,289,831 relates to the modification of the catheters and other
devices by incorporating glass spheres or high-density metal
particles in the range of 0.5 to 100 microns or partially spherical
indentations. U.S. Pat. No. 5,327,891 relates to the use of
microbubbles containing medium contained in vanes and/or tracks to
echogenically enhance catheters. U.S. Pat. No. 5,759,154 relates to
the utilization of a masking technique to produce depressions
comprising alternating rows of squares and diamonds on the surface
around the circumference of the device.
[0015] In our studies the known internal modifications of IUS's
(compounding with hollow glass microspheres, channelling, inserting
a metal core in the body of an intrauterine system) did not lead to
the desired effect, i.e. they did not sufficiently improve
visi-bility of the IUS in ultrasound detection. See FIG. 1, where
the difference of metal cored T-body (FIG. 1A, left side) with
surface modified T-body (FIG. 1B) is shown. Any material between
the probe and ultrasound enhancing material fades out partly or
totally the bright echogenicity of the ultrasound visibility
enhancer. However, a suitable means for improving the visibility of
IUS's was found by modifying the surf ace of the IUS with inert
metals. Although it is known that metals in general improve
echogenicity in ultrasound detection, in the prior art methods
metals have been used due to their contraceptive effect or to
enhance detection using X-rays. This invention concentrates on
means to improve ultrasound detection and to make certain parts of
the T-body of the product more visible than other parts, i.e. IUS
lo-cation and position in uterus can be quickly studied at the very
same clinician's ap-pointment.
SUMMARY OF THE INVENTION
[0016] The present invention thus provides an improved
ultrasonically detectable intrauterine system (IUS) for relatively
long-term insertion into a uterine cavity. The IUS according to the
invention comprises at least one image enhancing means for the
ultrasound imaging of the system. Said means are selected from the
group consisting of [0017] a) an inert metal coating on at least
part of the body of the intrauterine system; [0018] b) at least one
inert metal clip, pin, ring and/or sleeve fixedly positioned on the
body of the intrauterine system; and [0019] c) a metallic loop
anchored to the vertical arm of the body of the intrauterine system
in place of the usual loop.
[0020] The invention is also directed to a method for improving the
visualization of an intrauterine system within the uterine cavity
in an ultrasound examination. The method comprises i.a. the step of
providing the body of an IUS with at least one inert metal clip,
pin, ring and/or sleeve, applying an inert metal coating on at
least part of the body of an IUS, or anchoring a metallic loop to
the vertical arm of the body of an IUS. In some embodiments, the
metal ring forms a closed loop and surrounds ah upper end of a
vertical arm of the intrauterine system. In some embodiments, the
metal ring is a double ring that surrounds the upper end of a
vertical arm of the intrauterine system. In some embodiments, the
metal ring is at least partially embedded in an upper end of a
vertical arm of the intrauterine system.
[0021] The improvement of visibility of an IUS in an ultrasound
examination has the advantage of enabling health care personnel to
detect more easily the positioning of the device, thereby
facilitating the detection of both problems in placement of the
device and problems with the device itself.
[0022] Another advantage of this feature is that the positioning of
the IUS can be ascertained without a physical intrusion into the
area of the body wherein the device is inserted. Transvaginal or
abdominal ultrasound is nowadays a routine outpatient office
procedure, which has almost completely displaced the use of X-ray
examination in the detection of IUS's, in the ascertainment of the
correct location of the device. The ability to detect the IUS with
ultrasound examination is of vital importance in various clinical
situations, such as bleeding problems, pain, suspected expulsion
(i.e. displacement of the IUS), or other possible adverse effects
during IUS use. The correct location is determined by ultrasound
examination by measur-ing the distance between the upper end of the
vertical stem of the system to the outer surface of the fundus of
the uterus. As the uterus is not distinguishable in X-ray
examination, the use of ultrasound enables the ascertainment of the
correct location of the IUS more accurately than an X-ray
examination, e.g. in case of a partial expulsion of the device.
Further, the use of X-rays should be strictly avoided in the
general user population of IUS's, i.e. fertile aged women, to
minimize the exposure of reproductive organs to X-rays. Especially
the ovaries are very sensitive to the potential mutagenic effects
of X-rays, whereas ultrasound examination does not carry any of
such inherent risks. In summary, the present invention enables the
use of a safer and more reliable detection technique.
BRIEF DESCRIPTION OF THE FIGURES
[0023] FIG. 1A Ultrasound image of a metal cored T-body on the left
and reference IUS on the right.
[0024] FIG. 1B Ultrasound image of a surface modified T-body (with
metal). Surface modification enhanced echogenicity of T-body
remarkably. The images in FIGS. 1A and 2B were taken in in vitro
medium with convex probe.
[0025] Normally 2-dimensional view is used in medical sector. Thus
only horizontal arms (transverse view) or a vertical arm (sagital
view) can be seen at a time with a convex probe (FIG. 2A). By a
vaginal probe sometimes also a vertical arm can be seen (FIG.
2B).
[0026] FIG. 2A. Ultrasound image of T-body, transverse view with
convex-probe in water.
[0027] FIG. 2B A schematic model of a T-body with rectangle (1)
indicating which part of T-body can be seen in the picture in FIG.
2A.
[0028] FIG. 2C Ultrasound image of a T-body, viewed from the bottom
of the T-body in water with vaginal probe (also vertical arm is
visible).
[0029] FIG. 3 shows a comparative sagital view of the vertical arm
of a regular hormonal IUS (on the left) and a hormonal IUS with
metal (Au) coated T-body (on the right). Convex probe in potato
starch thickening. It is known that especially the hormone capsule
of an IUS fades out the echogenicity of the material underneath it.
Au-coating improved the echogenicity of the T-body and the T-body
is seen as bright image inside the hormone capsule.
[0030] FIG. 4A is a comparative sagital view of the vertical arm of
a T-body with metal (Ag) rings in upper and lower part of the stem
compared to FIG. 4B with a regu-lar T-body. Metal rings are seen as
a bright echo behind the vertical arm. Vaginal probe in potato
starch thickening.
[0031] FIG. 5. A drawing of a T-body with blue bands showing
optimal positions of echogenic enhancers, A, B, C, and D:
Echogenicity of place A or places A-B are the most important in
order to locate the distance of IUS from fundus. In order to
properly outline the position of horizontal arms in uterus,
echogenicity of positions C-D is important.
[0032] FIG. 6. A photograph of a hormonal contraceptive with
Au-coated T-body.
[0033] FIG. 7A. A photograph showing unembedded Ag-rings at the
upper and lower end of vertical arm of a hormonal IUS.
[0034] FIG. 7B A photograph showing embedded double-rings at the
upper and lower end of the vertical arm of a hormonal IUS.
[0035] FIG. 8. An ultrasound image showing acoustic shadowing
behind the horizontal arms of MIRENA.RTM.. Note triple shadowing
from the thickest parts of horizontal arms. MIRENA.RTM. is a
levonorgestrel-releasing intrauterine system (IUS), which consists
of a hormone-elastomer capsule, mounted on a T-body and covered
with an opaque tubing, which regulates the release of
levonorgestrel.
[0036] FIG. 9. Comparison of ultrasound image produced from a glass
microsphere modified 7-frame to a standard T-frame in corn starch
thickening by vaginal probe. The whole horizontal arm of the
7-frame is visible whereas only the three thickest parts of the
T-frame and their acoustic shadowing can be seen.
[0037] FIG. 10. Spherical ends of Au-coated T-body (marked with
arrows) were located from a sponge-water system.
[0038] FIG. 11. Ultrasound pictures comparing the brightness of
Ag-rings on the vertical arm (transverse view, vaginal probe) from
T-bodies with: Embedded single ring (FIG. 11A), Reference (no ring)
(FIG. 11B) and Embedded double ring (FIG. 11C).
[0039] FIG. 12. T-body design with positions (5 and 6) for embedded
metal rings at the ends of a vertical arm.
[0040] FIG. 13. A schematic picture of different loop designs (9,
10, and 11) together with T-body design for metals clips (7 and 8)
at positions (5 and 6) at the ends of a vertical arm.
DETAILED DESCRIPTION OF THE INVENTION
[0041] Ultrasound visibility or echogenicity of an intrauterine
device depends on the density difference of the adjacent materials,
the propagation speed difference of sound in the adjacent
materials, surface roughness, and the echogenicity of surrounding
materials. The ultrasound visibility of different material
modifications of IUS's can be estimated by evaluating the
echogenicity of the material from the calculated reflected
energies.
[0042] Sound travels through materials under the influence of sound
pressure. Because molecules or atoms are bound elastically to one
another, the excess pressure results in a wave propagating through
the solid. Acoustic impedance, Z (10.sup.5 g/cm.sup.2s), determines
the acoustic transmission and reflection at the boundary of
adjacent materials:
Z=.rho. v
wherein .rho.=density (g/cm.sup.3) and V=propagation speed
(mm/.mu.s).
[0043] Reflected energy R, can be calculated from the acoustic
impedances of adjacent materials (Z.sub.1 and Z.sub.2):
R = ( Z 2 - Z 1 Z 2 + Z 1 ) 2 ##EQU00001##
[0044] For transmitted sound energy: T=1-R. With these formulas the
ultrasound visibility of different modifications of IUS can be
estimated. The higher the reflected energy, the better the
echogenicity of the material.
[0045] In Table 1, the reflected and transmitted energies of
various material combinations are compared.
TABLE-US-00001 TABLE 1 Comparison of different material
combinations Reflected sound Transmitted Material 1 - Material 2
energy, R sound energy, T Human tissue - Copper 0.860 0.140 Human
tissue - MED 4735 tubing 0.032 0.996 Human tissue - PDMS 373 TW
tubing 0.020 0.980 Human tissue - PE-LD 0.004 0.997 Human tissue -
Glass (soda lime) 0.625 0.375 (PDMS = polydimethyl siloxane) (PE-LD
= low density polyethylene)
[0046] From Table 1 it can be seen that the copper wire of copper
IUDs and glass reflect most of the sound energy back, thus
providing good echogenicity and bright picture. Echogenicity of
elastomers and the usual body raw material of an IUS (PE-LD and
20-24% of BaSO4) is worse. Most of the sound energy is transmitted
through the material.
[0047] An intrauterine system according to the invention comprises
at least one image enhancing means for improving the ultrasound
imaging of the system. The means are selected from the group
consisting of [0048] a) an inert metal coating on at least part of
the body of the intrauterine system, [0049] b) at least one inert
metal clip, pin, ring and/or sleeve fixedly positioned on the body
of the intrauterine system, and [0050] c) an inert metallic loop
anchored to the vertical arm of the body of the intrauterine system
in place of the usual loop.
[0051] The metal is advantageously selected so that the reflected
energy at the boundary of adjacent materials is as high as
possible. Preferably the metal is selected from the group
consisting of inert metals, such as silver, gold, titanium,
tungsten, barium, bismuth, platinum and palladium. Preferred metals
are silver, gold, titanium and platinum, which are known to be
compatible (i.e. physically inert) with the human body. However,
copper may also be used.
[0052] In a preferred embodiment according to the invention, the
metal coating or the metal clips, pins, rings or sleeves are
located at the ends of the vertical arm(s) of the IUS having the
shape of the letter T or 7. This enables a physician to reliably
measure the distance of IUS from fundus. It is also possible to
coat the "loop" at the end of the vertical arm of the IUS, or to
fix a metal ring, pin or sleeve at the foot of the loop. In a
further preferred embodiment, the metal coating or the metal clip,
pin, ring or sleeve is located only at the "upper" end of the
vertical arm of the IUS.
[0053] Sometimes it is also important to locate the position of
horizontal arms of a T-body. This can be achieved by metal coating
the whole T-body or by incorporating metal clips, rings or sleeves
also to the end of horizontal arm(s) (before spherical ends) (FIG.
5).
[0054] Typically the thickness of the metal coating may vary from
between about 0.1 nm and about 500 nm, preferably between about 1
nm and about 50 nm. However, even thicker coatings of about 0.1 mm
are possible.
[0055] The metal clips, pins, rings or sleeves may be unembedded or
at least partly embedded in the body of an IUS. Partial embedding
of the rings smooths the surface of the IUS while not yet impairing
the visibility compared to unembedded counterpart. In case of rings
it is advantageous to use double rings to enhance echogenicity. In
case of clips and sleeves, the broader the clip or sleeve, the
better is the visibility. The width of the metal clip, pin, ring or
sleeve may vary for example from 0.2 to few millimetres, being
preferably about 1 mm, or in case of double rings about 0.5 mm A
further embodiment is to fix a metal pin of an appropriate size
through the loop, so that the ends of the pin which are larger than
the diameter of the loop are visible.
[0056] The intrauterine system according to the invention may also
have locking means, typically at least two locking parts, between
which the medicated capsule is mounted. The locking parts keep the
capsule in the correct position during the insertion, use and
removal of the IUS. Said locking parts may have different shapes,
e.g. a shape of a truncated cone. They can be made of a polymeric
material, which can be the same or different from the material of
the body, but other materials can also be used, for example in this
case an inert metal which improves visibility of the IUS in an
ultrasound examination.
[0057] The intrauterine system according to the invention has been
designed for a relatively long-term insertion into a uterine
cavity. However, a long-terms insertion may vary greatly, for
example from a couple of weeks to several years, the maximum IUS
usage time being typically up to five years.
[0058] The invention is also directed to a method for improving the
visualization of an intrauterine system within the uterine cavity
in an ultrasound examination, comprising at least one of the steps
of [0059] applying an inert metal coating on at least part of the
body of an IUS, or [0060] providing the body of an IUS with at
least one inert metal clip, pin, ring and/or sleeve, or [0061]
anchoring a metallic loop to the vertical arm of the body of an
IUS; inserting the IUS into the uterine cavity and examining the
position of the IUS within the uterine cavity in an ultrasound
examination at an appropriate point of time.
Experimental
Experimental in Vitro Conditions:
[0061] [0062] PE-container filled with water, corn starch
thickening or potato starch thickening [0063] Test specimen placed
inside a sponge and the system immersed into water
Apparatus:
[0063] [0064] Sonosite 180PLUS, with convex (2-4 MHz) and vaginal
(4-7 MHz) probes or [0065] Aloka SSD 900, with convex (3.5 MHz) and
vaginal (7.5 MHz) probes
Studied Modifications:
[0065] [0066] Group 1: Hollow glass microspheres have been
incorporated in the raw material of the frames (bodies). Due to
high density and entrapped air inside, the echogenicity should be
improved. [0067] Group 2: Hollow glass microspheres have been
incorporated in the hormone-releasing core. [0068] Group 3: The
whole T-body is Au-coated using Jeol Fine Coat ion sputter JFC-1100
equipment (1 kV voltage and 1 mA current for 20 minutes). The
obtained thickness of the Au-layer was few nanometers. See FIG. 6.
[0069] Group 4: Rings or double rings of 0.5 mm thick silver wire
were positioned adjacent to the ends of the vertical arm of the
T-body. Both embedded and unembedded fixing was investigated with
the currently available T-frames. A rough embedding was made
manually by scooping out a channel with depth of about 0.25 mm. See
FIG. 7.
Other In Vitro Conditions:
[0069] [0070] Potato starch and corn starch thickenings behaved
similarly in the sonography. [0071] The scattering and attenuation
of sound waves and the avoidable presence of air in the sponge
system was so high that only NOVA T.RTM. 380 (vertical arm) was
located. (NOVA T.RTM. is a T-shaped plastic frame, which has a
copper wire or a silver cored copper wire surrounding the vertical
arm of the T.) [0072] Water as an in vitro medium was found worse
than the other media due to too good echogenicity of studied
specimens in water. No differences in echogenicity between the
samples were detected. Sound wave proceeds easily through water and
no disturbing echoes are formed. Acoustic shadowing, the typical
phenomenon of IUD's and IUS's is very difficult to be detected in
water as water is seen black in a sonograph. (In FIG. 8 an example
of the acoustic shadowing of MIRENA.RTM. in potato starch
thickening is presented.)
Comparison of Different Modifications:
[0072] [0073] Glass microspheres in T-frame improved echogenicity
slightly. See FIG. 9 where glass microsphere modified 7-frame and
standard T-frame are compared in corn starch thickening. [0074]
Au-coating improved echogenicity of T-body. T-body is seen as a
bright image under hormone releasing capsule. See FIG. 3. Even in
the sponge system which was found to be very challenging in vitro
medium, the spherical ends were located. See FIG. 10. [0075] 0.5 mm
thick Ag-wire placed on the upper and lower ends of the vertical
arm enhanced the echogenicity. See FIG. 4. Metal rings were seen as
bright white spots and their location during investigation was
easy. Partial embedding of the rings did not impair the visibility
compared to unembedded counterpart in any projections. However, it
was obvious that a double ring behaved better than a single ring.
The sonograph from double rings was larger and brighter. See a
comparative picture, FIG. 11, where the ring, double-ring and
no-ring have been examined in optimal projection.
* * * * *