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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5809_Библиотеки_им_академика_М_И_Перельмана.pdf
Virtual Hysterosalpingography:
ANoninvasive Diagnostic
Technique fortheEvaluation
oftheFemale Reproductive Tract
PatriciaCarrascosa, CarlosCapuñay,
JuanMarianoBaronio, andCarlosE.Sueldo
21
General Concepts
Virtual studies started to be implemented in 1994,
with the introduction of the computed tomography (CT) virtual colonoscopy. Since then, new
CT virtual evaluations of several organs, such as
the airways and the urinary tract, among others,
started to be developed. However, it was not until
several years later that this novel technique was
used in the evaluation of the female reproductive
system.
After 8 years of development and improvement of both acquisition protocols, technique of
realization and CT scanner capabilities, CT virtual hysterosalpingography (VHSG) was introduced in the clinical scenario by October 2006
[1–3]. Nowadays, this technique allows, in about
2s, the full evaluation of the entire female reproductive system, giving information on the cervix,
uterine cavity plus uterine walls, fallopian tubes,
and other pelvic structures.
P. Carrascosa · C. Capuñay (*)
Department of Computed Tomography and Magnetic
Resonance, Diagnóstico Maipú, Buenos Aires,
Argentina
e-mail: carloscapunay@diagnosticomaipu.com.ar
J. M. Baronio
Department of Fertility, CEGYR,
Buenos Aires, Argentina
C. E. Sueldo
University of California San Francisco-Fresno,
Department of Obstetrics and Gynecology,
Fresno, CA, USA
Virtual hysterosalpingography should be performed, using multislice CT scanners with at
least 64 rows, to assure an adequate CT acquisition, in order to optimize its diagnostic potential
[4]. The temporal, spatial, and contrast resolutions of the study will be based on the number of
rows present in the CT scanner (currently, there
are scanners with up to 520 detector rows).
The temporal resolution is mandatory, to
capture the complete anatomy and patency of
the fallopian tubes. Temporal resolution varies
according to the gantry rotation time, which
ranges from 350 to 270ms. The faster the gantry rotation time, the better its temporal resolution [5].
The entire examination is performed in a very
short period of time that varies from 1.3 to 3s.
During this time, CT images are acquired and
subsequently processed in a workstation, using
different algorithms, such as multiplanar reconstructions, maximum-intensity projections,
volume- rendering 3D images, and endoscopic
views.
Patient Preparation fortheStudy
It is mandatory to perform the study between
days 6 and 11 of the menstrual cycle. In order to
avoid any potential pregnancy, sexual abstinence
during 2days before and 2days after the day of
the study is recommended. Contraindications to
© Springer Nature Switzerland AG 2019
L. A. Stadtmauer, I. Tur-Kaspa (eds.), Ultrasound Imaging in Reproductive Medicine,
https://doi.org/10.1007/978-3-030-16699-1_21
345
346
P. Carrascosa et al.
perform the study besides pregnancy are pelvic
infections or bleeding.
The day of the exam, patients are asked to
avoid emptying the bladder for 2 h before the
study, in order to straighten the uterine axis in
anteverted uterus, as it contributes to change it to
a more neutral position. Additionally, patients
can take analgesics 1h before the study.
Preparation ofPatients intheCT
Room
Patients are placed on the CT table in gynecologic position. After cleaning the perineum and
vagina with povidone-iodine solution, a speculum is placed into the vagina to visualize the
external cervical os. Complete sterilization of the
vagina and the uterine cervix is carried out.
In order to instill an iodine contrast dilution
(3 mL of water-soluble iodine contrast and
17mL of saline solution) into the uterine cavity,
a device specially designed for this purpose is
positioned in the lateral portion of the speculum
(Fig.21.1). It will keep centered in place a plastic cannula positioned at the external cervical
os. This cannula will be connected to a power
injector, which will inject the mixed solution at
a very slow rate (0.3ml/s), in order to reduce
patient’s discomfort during the procedure and to
assure an optimal uterine distention. The CT
image acquisition begins 12s after starting the
mixture instillation. Using a 256 or 320 slice CT
scanners, the study is completed in only 1.3s,
making VHSG a real- time study with easy visualization of the contrast, as it passes into the
peritoneum.
Technical parameters of these studies are slice
thickness, 0.625mm; gantry rotation time, 270–
350ms; kV, 80–120; and mAs, 100–200. X-ray
tube current and potency are adjusted in relation
to patient’s weight and body mass index. It is
always preferable to use the least mAs and kV
necessary. Small patients usually receive
80kV–100 mAs, with an exposure radiation dose
of 0.3mSv. After performing an anteroposterior
scout view of the pelvis, a 10-cm length CT scan
is planned, centered on the pelvic region. Once
the CT images are acquired and checked by the
physician performing the examination, the cannula and speculum are removed, and the perineum
is cleansed with povidone-iodine solution.
Patients can return immediately to routine
activities.
Complications oftheProcedure
The rate of complications of VHSG in our experience is extremely low; in over 15,000 VHSG
studies performed since 2006, we did not nd any
cases of infection, bleeding, or other signicant
complications requiring hospitalization. In a few
cases we observed intravascular passage of contrast through the uterine plexus, and only three
patients experienced an allergic-like reaction
requiring medical treatment, with symptoms
improving in a very short time.
Patient’s Acceptance
VHSG is a well-tolerated exam, as is commonly
not associated with any signicant discomfort.
From all cases of VHSG performed in our center,
the majority of the patients (85%) classied the
procedure as having no discomfort or mild discomfort only [6, 7].
Fig. 21.1 Instruments
used in VHSG exams
21 Virtual Hysterosalpingography: ANoninvasive Diagnostic Technique fortheEvaluation oftheFemale…
Contraindications
Contraindications to perform the procedure are
pregnancy and active pelvic infection. Allergy to
iodine is a relative contraindication, and in known
cases, gadolinium can be used instead [8]. Our
group conducted a study including 50 patients,
comparing the diagnostic performance of VHSG
using the conventional iodine-saline solution
mixture versus those using a mixture of gadolinium and saline solution. Diagnostic results were
similar; and the main limitation of using gadolinium is its higher cost; for that reason we prefer
using iodine, as the contrast agent.
347
Radiation
Although in the rst developmental stages of the
procedure, more than 10 years ago, radiation
doses of VHSG were more than 1mSv, nowadays
with the introduction of new CT scanners and the
implementation of iterative reconstruction algorithms, radiation doses are signicantly reduced
to around 0.3 mSv. With these values, VHSG
gives a lower radiation doses than a conventional
X-ray hysterosalpingography, which has a variable radiation dose of 1–3mSv, based on the uoroscopy time and number of X-ray spots. The
use of a radiation dose as low as reasonably
achievable (ALARA) is mandatory, particularly
when relatively young patients and the gonadal
region are involved in the study.
Image Post-Processing
Once the images are acquired, two- and threedimensional evaluations are routinely performed
by the physician at a workstation, to perform the
diagnosis. During the image interpretation and
analysis, as mentioned earlier, different postprocessing algorithms are used:
Multiplanar Reconstructions (MPR) These
types of image reconstructions show the complete reproductive tract in different views and
angles (coronal, sagittal, and oblique planes).
Fig. 21.2 VHSG maximum-intensity projection image
of normal, patent fallopian tubes
Even curved multiplanar reconstructions can be
created, unfolding the cervix and uterine cavity
in a single view. MPR can assess all types of
pathologies, such as polyps, synechiae, and uterine anomalies, among others, and perform all
sorts of measurements (Fig. 21.2). Also extragynecologic pelvic structures can be evaluated.
Maximal Intensity Projection (MIP) These
images provide excellent denition of the anatomy and lumen of the fallopian tubes, in a grayscale tridimensional dimension (Fig. 21.3),
facilitating the detection of hydrosalpinx, as well
as tubal obstructions.
Volume-Rendering (VR) Images These images
created tridimensional views of the reproductive
tract, using a window that recognizes the intrauterine contrast. These reconstructions detect a
large spectrum of uterine and tubal pathology,
such as cervical stenosis, polyps, and tubal disease (Figs.21.4, 21.5, and 21.6). They are also
very useful in conrming suspected ndings
visualized on the MPR.
Virtual Endoscopy (VE) Images This analysis
is the last step in the image interpretation process, and it allows performing a nal diagnosis.
348
Fig. 21.3 VHSG coronal multiplanar reconstruction of a
9-mm endocervical polyp
P. Carrascosa et al.
Fig. 21.5 VHSG volume-rendering image of an endome-
trial polyp (arrow)
Fig. 21.4 VHSG volume-rendering image of a cervical
synechiae (arrow)
Images are very similar to gold standard invasive
diagnostic methods, such as hysteroscopy and
falloposcopy (Fig.21.7). Nevertheless, there are
some differences between endoscopic views by
VHSG and conventional hysteroscopy. VHSG
endoscopic images can show all views in any
angle, plus the software can display navigation
from the cervix to the uterine fundus and fallo-
Fig. 21.6 VHSG volume-rendering image of a submuco-
sal myoma (arrow)
pian tubes or in the opposite direction, while conventional hysteroscopy can only show navigation
in a single direction.
A limitation of VHSG is that the endoscopic
views do not show the real color of the mucosa
and that it is only a diagnostic modality, meaning
it is not therapeutic, as is the case with
21 Virtual Hysterosalpingography: ANoninvasive Diagnostic Technique fortheEvaluation oftheFemale…
349
Fig. 21.7 Virtual endoscopy view of normal uterine
cavity
conventional hysteroscopy, in cases where
pathology is encountered.
Clinical Experience withVirtual
Hysterosalpingography
inReproductive Medicine Cervical
Pathology inInfertility
The cervical anomalies may include different
types of pathologies, such as cervical stenosis,
synechiae, cervical wall irregularities, polyps,
and diverticula. Many of these processes can
reduce the lumen of the cervical canal and
obstruct the intracavitary access in patients
undergoing intrauterine inseminations or
embryo transfers, negatively impacting outcome. Also a narrow cervical-uterine angle
decreases the performance of these procedures.
This angle, determined by the intersection on a
line passing through the longitudinal axis of the
cervical canal and other through the longitudinal axis of the uterine cavity, can be routinely
measured on the VHSG studies. Regarding that
its value varies according to bladder distention,
it should be measured with full bladder; an
angle greater than 90° facilitates the performance of the embryo transfer procedures
(Fig.21.8).
Fig. 21.8 VHSG sagittal maximum-intensity projection
image showing a wide cervical-uterine angle
Fig. 21.9 VHSG maximum-intensity projection image
of cervical stenosis (arrow)
Narrowing of the cervical canal has different
etiologies such as congenital or postsurgical/
instrumental trauma or post-infection. VHSG can
evaluate the complete cervix without any blind
spot after image reconstruction. The MPR, MIP,
and VR images are extremely useful in the
diagnosis of cervical stenosis (Fig. 21.9), while
VE images allow the navigation through the cervical lumen clearly identifying the cervical
alterations.
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P. Carrascosa et al.
Cervical synechiae are characterized by the
presence of brous tissue bands that partially or
totally occupy the cervical canal. VHSG identies elevated irregular soft tissue lesions extending from the cervical wall toward the cervical
lumen. In severe cases, the lumen can be severely
reduced, and the synechiae extend diffusively
from one wall to the other (Fig.21.10).
Cervical polyps are elevated lesions which
vary in size and number. They may result from
an abnormal response to the presence of high
levels of estrogens, chronic inammation, etc.
and can be either asymptomatic or present with
vaginal bleeding during intercourse or any
other cervical manipulation. They are rarely
malignant, but after removal they should always
be sent to pathology. They are seen by VHSG
partially or totally obstructing the lumen; the
MPRs show a soft tissue lesion projecting into
the uterine cavity, and the virtual endoscopy
shows the endoluminal view of the polyp
(Fig.21.11).
Fig. 21.10 Cervical synechiae (arrow) seen by (a) VHSG maximum-intensity projection image and (b) virtual endos-
copy view
Fig. 21.11 Cervical polyp (arrow) seen by (a) VHSG sagittal multiplanar reconstruction and (b) virtual endoscopy
view
ab
21 Virtual Hysterosalpingography: ANoninvasive Diagnostic Technique fortheEvaluation oftheFemale…
351
The cervical diverticula are herniations of the
cervical wall that can be seen by VHSG through
tridimensional and endoscopic views, where one
can clearly detect the neck of the diverticulum
projecting into the lumen. It is unclear if diverticula play a role in human infertility.
Pathology oftheEndometrial
Cavity inInfertility
Different pathologies can affect the endometrial cavity and can compromise sperm transport, embryo implantation, or embryo growth,
potentially increasing the rate of spontaneous
miscarriages [9]. VHSG can detect all of them
in a noninvasive manner with excellent diagnostic accuracy. Our group has done a comparison between VHSG and conventional
hysteroscopy in 69 infertile patients, showing a
sensitivity of 96%, a specicity of 86%, a positive predictive value of 90%, and a negative
predictive value of 95.6% for all lesions in
comparison with the gold standard technique of
hysteroscopy.
Uterine congenital anomalies are well
assessed by VHSG [10]. Although magnetic
resonance imaging has been considered the
modality of choice for their diagnosis, VHSG
has shown similar results for their identication
with the potential advantage of identifying
associated lesions, such as polyps or synechiae,
among others. Septate uterus can be clearly differentiated from bicornuate uterus by
VHSG. An accurate diagnosis is important in
order to properly advise patients about the best
treatment to be implemented. Recently, we
demonstrated the value of VHSG in the differential diagnosis of these uterine anomalies, as
one can easily outline the external surface of
the uterine fundus. VHSG with volume-rendering reconstruction allows the visualization of
the endometrial cavity plus the adjacent at or
minimally indented myometrium consistent
with a septate uterus (Fig.21.12). On the other
hand, when the indentation in the uterine fundus is deeper than 15mm, creating the presence
of two separate horns, the diagnosis of bicornuate uterus is made (Fig.21.13); the endoscopic
view of the cavity is unable to differentiate
between septate and bicornuate uterus
(Fig.21.14).
Uterine synechiae can also be easily observed
by VHSG, as brous bands that connect the
Fig. 21.12 Partial septate uterus seen by (a) VHSG volume-rendering image and (b) maximum-intensity projection
image
352
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P. Carrascosa et al.
uterine walls to one another. They represent scars
usually caused by trauma, the result from an
aggressive curettage post-abortion or postpartum. Their presence may be localized in a small
section of the uterine cavity or extensively spread
out in a diffuse manner, obliterating large sectors
of the uterine cavity (Fig.21.15). They can cause
infertility or repeated pregnancy losses. VHSG is
Fig. 21.13 Bicornuate uterus seen by VHSG coronal
multiplanar reconstruction showing the indentation in the
uterine fundus (arrow)
an excellent diagnostic tool as MPR shows irregularly elevated lesions with soft tissue density,
while volume-rendering reconstructions show
lling defects where the synechiae are located.
Endometrial polyps consist of focal overgrowths
of the endometrium, and they are also easily
diagnosed by VHSG, as focal elevations of the
endometrium projecting from the uterine wall to
the endometrial cavity. Multiplanar reconstructions allows to accurately measure their sizes,
while the VR images show them as lling defects
in the uterine morphology. Finally VE images
show the elevated lesion projected into the uterine cavity (Fig.21.16).
The association between polyps and infertility
is controversial, but there is some consensus that
those polyps larger than 1cm should be removed,
especially when present in patients going for
invitro fertilization or similar procedures.
Submucous myomas are generally benign
tumors from the smooth muscle, single or multiple, with a variable size, number, and location.
They may be a cause of infertility depending on
their location and size, as they may interfere
with sperm transport and/or embryo implantation; they may also be a cause of repeated miscarriages. VHSG can help in showing the exact
location of the lesion, to determine the best sur-
Fig. 21.14 Virtual endoscopy view of (a) partial septate uterus and (b) bicornuate uterus
ab
ab
21 Virtual Hysterosalpingography: ANoninvasive Diagnostic Technique fortheEvaluation oftheFemale…
Fig. 21.15 Uterine synechiae (arrow) in a bicornuate uterus seen by (a) VHSG volume-rendering image and (b)
maximum- intensity projection image
353
Fig. 21.16 Endometrial polyp (arrow) seen by (a) VHSG volume-rendering image and (b) virtual endoscopy view
gical approach for its removal and predict the
chances of success for the procedure
(Fig.21.17).
and patency. Currently, VHSG can also play an
important role in their evaluation. As mentioned,
it is mandatory to perform the VHSG studies with
CT scanners of 64 or more rows, in order to capture the fallopian tubes distended with contrast
Evaluation oftheFallopian Tubes
along its whole length. MIP images are the best
image post-processing tool to evaluate their mor-
Conventional X-ray hysterosalpingography has
traditionally been considered the gold standard
for assessment of the fallopian tube morphology
phology and identify any kind of pathology such
as tubal obstruction, hydrosalpinx, tubal polyps,
or adhesions (Fig.21.18).
354
P. Carrascosa et al.
a b
Fig. 21.17 Submucosal myoma (arrow) seen by (a) VHSG maximum-intensity projection image and (b) virtual endos-
copy view
a
b
c
Fig. 21.18 Large right hydrosalpinx seen by (a) VHSG maximum-intensity projection image, (b) VHSG volume-
rendering image, and (c) virtual endoscopy view