How
useful is transvaginal pulsed Color
Doppler in ART programme??
An experienced sonologist can
interpret about i. e 1) Oocyte maturity 2) the predictability of the number and 3) quality
of the oocytes and 4)
assessment of the most appropriate timing of the administration of human chorionic
gonadotropin in cases of
assisted conception by interpreting the Pulse colour Doppler !!!!
Part
I: How useful is transvaginal pulsed
Color Doppler One need
the combination of real time
ultrasound pulsed Doppler and
color flow mapping in studying the female reproductive system on an anatomic and
physiological basis . Only then it will be successfully possible to
assess the hemodynamic changes in various physiological and pathological entities in uterus, ovaries and endometrium
in particular.
In fact in many centers the costs of endocrine
assessment in the middle part of ART
cycle have been minimized thereby avoiding -repeated venepunture!! .
ART
specialist for last three decades were desperately searching for a non invasive procedure
that will improve precision of the knowledge of A) oocyte
maturity B) the predictability of the number and C) quality of the oocytes and D) assessment of the most appropriate timing of the administration of human chorionic
gonadotropin in cases of assisted
conception. With the advanced technology
of Sonology & its capability to interpret
the vascular changes that
occur in the intraovarian
milieu using transvaginal pulsed
Color Doppler have improved
their understanding of the peripheral circulatory
conditions that reflect the hormonal changes that occur
during spontaneous and induced cycles.
.
Part II : Let us refresh our memories on Vascular supply of the ovaries before we embark upon
to interpret the Doppler changes of
ovarian vessels in an induced cyce?
What is genital
vascular arcade?? Ans: Ovarian
arteries are branches of abd aorta with high blood flow though Lt ovarian vein
drains into Lt renal vein. The ovary receives its arterial
vascularity from two sources the A) ovarian artery and the B) utero ovarian branch of the uterine artery . These
arteries anastomose to form an arch parallel to the ovarian hilus and
constitute the vascular genital arcade.
I don’t know how the ovarian function is interfered when on PPH cases the
uterine arteries orsay Int iliac arteries are ligated!!!
However, from
the ovarian hilus the arterial
branches penetrate the stroma and acquire a tortuous
and helical pathway termed the spiral or helical arteries demonstrating high resistance to flow. This facilitates
the accommodation to changes in size
with development of the follicle.
Arterial tone can be assessed by Pulsed Colour Doppler if one have such
a machine & clinic provided sonologist keeps her / his word visits to your
clinic at a particular time : That can be done at your clinic!!! Intravascular
pressure and diameter profile of the utero-ovarian resistance artery network: Modulation
of resistance or changes in artery tone by hormones, Quality of growing oocyte,
No of D follicles instead of repeated
endocrine profile..
Blood flow to the ovary varies
dramatically in both magnitude and distribution throughout the estrous cycle to
meet the hormonal and metabolic demands of the ovarian parenchyma as it
cyclically develops and regresses. Several vascular components appear to be
critical to vascular regulation of the ovary. As a first step in resolving the
role of the resistance arteries and their paired veins in regulating ovarian
blood flow and transvascular exchange, researchers
have characterized
the architecture and intravascular pressure profile of the utero-ovarian
resistance artery network in an in vivo preparation of the ovary of the
anesthetized Golden hamster.
Researchers have evaluated on anesthetized
Golden hamster. And investigated estrous cycle-dependent changes in resistance
artery tone.
The right ovary and the cranial
aspect of the uterus in 26 female hamsters were exposed for microcirculatory
observations. Estrous-cycle phase was determined in each animal before experimentation.
The utero-ovarian vascular architecture was determined and resistance artery
diameters were measured in each animal by video microscopy. Servo-null
intravascular pressure measurements were made throughout the uteroovarian
arterial network in 11 of the animals. Architectural data showed a complex
anastomotic network jointly supplying the uterus and ovary.
Resistance arteries showed a high degree of
coiling and close opposition to veins, maximizing countercurrent-exchange
capabilities.
Arterial pressure dropped below 60% of
systemic arterial pressure before the arteries entered the ovary. Both the ovarian
artery and the uterine artery, which jointly feed the ovary, showed cycle
day-dependent changes in diameter.
Arterial diameters were smallest on the day
following ovulation, during the brief luteal phase of the hamster. The data
show that resistance arteries comprise a critical part of a complex network
designed for intimate local communication and control and suggest that these
arteries may play an important role in regulating ovarian blood flow in an
estrous cycle-specific manner.
Part IV:- If sonologist fails
to come then it is you who have to do
it. Here are
tips:-After visualization of the pelvic anatomy
by B mode and color Doppler
sonography the color flow of
the ovaries can be
explored with Doppler sample volume
until the typical spectral waveform is seen. As the ovarian artery traverses
the broad ligament entering the
ovary at an angle of approximately 90 degrees
to the insinuating vaginal ultrasound
beam, satisfactory ovarian Doppler
signals are difficult to obtain vaginally.
However intraovarian vessels traverse the ovary at varying angles
of orientation. With the increased blood supply
to the ovary containing the
corpus luteum vessels are relatively
easily identified with a color
system at low angles of
insinuation. It is additionally difficult
to visualize ovarian vessels because
the color flow is usually not
prominent velocity is low and the
resistance varies according to the day of the menstrual cycle.
Nevertheless
it should be emphasized that the
information obtained by color
Doppler sonography is rarely
diagnostic by itself. It should also be noted
that blood flow demonstrated
with color Doppler images that depends on flow velocity is not directly dependent on the amount of blood flow and the diameter of a
vessel. Therefore the vascularity seen on a color flow image does not always correlate
with that assessed by angiography or dynamic computed topography.
Part
VI:- Doppler studies while performing Foll
monitoring . Blood flow during
the follicular periovulatory and mid
luteal period in spontaneous and induced cycles
: The ovarian blood flow of an ovulatory cycle is more or less at constant level throughout the follicular phase
and then shows a steady decline
to reach a nadir on the approach to
ovulation. These blood flow changes are not seen in anovulatory cycles.
The blood flow changes that occur before ovulation indicate the complexity of changes that involve angiogenesis
as well as hormonal factors .
Furthermore
corpus luteum blood flow is characterized by low impedance and high
flow pattern that can easily be detected One study
measured the resistance
index of the flow velocity
waveforms of the uterine and the
ovarian arteries during the menstrual cycle in 100 infertile anovulatory
women compared with 150 fertile
spontaneously ovulating women. The
authors recognized that the RI of the uterine
arteries was around 0.88
until day 13 of a 28 day cycle. Then a significant decline began reaching
0.84 at day 16.
These changes did not occur in anovulatory cycles in contrast
there was an increase in the RI .
However ovarian flow velocity
differs somewhat from the uterine vasculature where the
resistance index is
approximately 0.54 until ovulation
approaches after
which a decline begins 2 days before ovulation and reaches a nadir at ovulation . Thereafter it remains
at this low level for four more days and gradually climbs to a level of 0.50 .Another
study has looked at the intraovarian
blood flow during the early
follicular, periovulatory and mid
luteal phases in spontaneous and
induced ovarian cycles. The researchers measured the pulsatility index in 8 women
with spontaneous cycles 20
women undergoing induction of ovulation with clomiphene citrate and 11 women undergoing controlled ovarian stimulation
for in vitro fertilization with gonadotropin releasing hormone agonists
, stimulation by human
menopausal gonadotropin and trigger by
human
chorionic gonadotropin .
Although statistically non significant the intraovarian PI showed a gradual decrease
from the early follicular
through eh periovulatory to the mid luteal phase .
Intraovarian blood flow velocity wave from
were found in 20. 5 % of cases at
the early follicular phase , in 56%
of cases during the peri ovulatory phase, and in 85% during the mid luteal phase.
Intraovarian blood flow in relation to ovarian morphology and function
during the periovulatory period In
addition the indices of the blood flow
at a given site within the leading
follicle have been monitored by
transvaginal color Doppler imaging
over the periovulatory period . Researchers have assessed by intraovarian blood flow in relation to ovarian morphology and function during
the peri ovulatory period.
The main outcome
measures were the PI and the maximum peak systolic velocity from vessels within the dominant follicle the maximum
follicular diameters and
its correlation with serum FSH , LH,
and progesterone levels .
POINT VII: What changes happens in blood vessels just prior to ovulation??
Ans: There is an apparent
A) increase in the intra
follicular blood flow over the periovulatory
period with an insignificant trend
toward B) lower values for the
mean PI and a C) significant trend toward lower values for the mean PI and a
D) significant increase in the
peak systolic velocity.
These
changes appeared to follow the rise
in circulating LH. The increase in the peak
systolic velocity and the relatively constant PI suggest
a marked increase in blood
flow at this time during the ovarian
cycle and might herald
impending ovulation .
Others have examined the uterine and ovarian
perfusion during the peri ovulatory period. The researchers measured the flow velocity
of the uterine radial spiral and
ovarian arteries during the peri
ovulatory period in spontaneous and induced
ovarian cycles .They demonstrated that ovarian flow
velocity had a RI of 0.52
on the day before ovulation in
the group with spontaneous cycles and
0.51 in the group with stimulated cycles
. The value for
the RI tended to decrease whereas blood velocity tended to increase during the
day after ovulation . A nadir
of 0.46 was reached one day
after ovulation in the group with
spontaneous cycles and of 0.43 in the
group with stimulated cycles. However there were no statistically significant differences in the results between
spontaneous and stimulated cycles.
Part
: VIII: Role of transvaginal
pulsed color Doppler in assisted conception
In the in vitro
fertilization embryo
transfer program : The oocyte
quality and recovery the embryo
quality and the receptivity
of the endometrium are
among the most important parameters that determine the success rate. Several studies noted that the perifollicular peak velocity values increase gradually with the
increase in size of the growing
follicles. In addition there is a strong positive correlation between the size of the ovarian follicles and their peak velocity which
suggests an increase of blood
flow around developing follicles in the course of the follicular phase .
Moreover
hCG plays an important role in inducing an influx of blood
within the follicles. However it appears that the resistance index is not a useful parameter for characterization of the
intra follicular flow color
Doppler.
But the assessment of folliculogenesis in IVF- ET
patients was studied in women undergoing
hormonal stimulation for IVF. A highly
significant elevation of the peak velocity was observed especially after hCG injection. Such rapid rise of blood velocity was greater
in the right ovary than in the
left. This may be a cause of more ovulation in Rt side of ovary in unstimukated
cycles.
Part
IX: The role of transvaginal pulsed
color Doppler ultrasound in the prediction of th outcome of an in vitro fertilization program has been assessed in several studies. Researchers have followed
longitudinally during stimulated cycles
and the PI and the maximum peak systolic velocity of the
intra ovarian and the uterine blood flow were measured . There were no detectable changes in Doppler measurements affecting
the intra ovarian blood flow.
All flow velocity wave forms obtained from intra ovarian vessels showed a low resistance
with continuous end diastolic
component . The highest individual PI
value was less than 1.1
. It is suggested that the plateau seen in the Doppler
parameters of the intra ovarian blood flow
may be explained by the small
peri follicular vessels in the ovary
that appear to offer minimal resistance to blood
flow. This operates as if they are maximally dilated and consequently once the optimal flow conditions are achieved further changes in endocrine profile may not be
reflected in the Doppler parameters
of the ovarian blood flow. Secondly the endocrine profile in IVF therapy with
GnRH a differs from that in spontaneous cycles . the most important
feature being the lack of the
physiological LH surge prior to the
follicular aspiration therefore
the cyclic changes seen in Doppler parameters taken during
spontaneous cycles do not necessarily occur
during the stimulation protocol
used in IVF. Thus the PI and PSV
values of the blood flow in
these arteries were much lower than those of the uterine artery. In addition as a consequence of angiogenesis , the peri
follicular blood vessels
have a different vessel wall structure
from that of uterine
artery. It was noted that the
detection rate of blood vessels around
the developing follicles was 34%
during suppression with GnRH
as compared with 86% at the time of follicular
aspiration. The low detection rate of the
intra ovarian vascularity
during the suppression period shows
a novel effect of the pituitary desensitization when ovaries are in a resting state with
no folliculogenesis.
The
basic keystone of the hemodynamic regulation of the intra ovarian
blood flow is the accentuation of
the blood perfusion of the ovaries during
hormonal stimulation . This augmentation in perfusion is demonstrated by an increasing number of vessels around the developing follicle and the acceleration in the peak velocity of the blood flow in the uterine and
intra ovarian arteries .
Some authors
proposed correlating the ultrasound derived indexes of the blood flow in individual follicles on the day of but before th administration
of hCG with the subsequent recovery
of the oocytes and the production
of Perimplantation embryos . Researchers
have collected data obtained
from women undergoing IVF-ET.
The peak systolic velocity was higher in follicles
that this information may also be used to time the administration of hCG to achieve the optimum number and
quality for patient management. However there was no clear
difference in either PI or PSV
values between pregnant and nonpregnant women making prediction
of the outcome of the
treatment not feasible with Doppler .
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