Keywords
imaging - infertility - tubal - HSG - ultrasound - MRI
Introduction
Infertility is an escalating global concern, impacting approximately one-sixth of
the reproductive-age population worldwide. Infertility, by definition, means the inability
of a couple to conceive after 1 year of unprotected intercourse.[1]
[2] Infertility impacts 60 to 80 million couples globally, with a significant 25% of
these cases occurring in India alone. The prevalence of female infertility in India,
as per the National Family Health Survey-5 (2019–21), is 18.7 per 1,000 women among
those married for at least 5 years and currently in union.[2]
Infertility has a deep impact on the couple in terms of psychological, emotional,
and financial stress. The patients require an empathetic and supportive approach.
It often has a multifactorial origin, thus needing an integrated approach and evaluation
of both partners for diagnosis and management. Although the gynecologists initially
emphasize a detailed medical history, physical examination, serum hormonal evaluation,
and detection of ovulation, female pelvic imaging still plays a crucial role in determining
the cause of infertility. The causes of female infertility can be broadly classified
as hormonal, adnexal, uterine, endometrial, cervical, vaginal, and ovarian ([Fig. 1]). This comprehensive review illustrates the various causes of female infertility,
where imaging plays a significant role.
Fig. 1 Flowchart showing various causes of female infertility.
A radiologist must prioritize accurate diagnosis through careful image interpretation
while minimizing radiation exposure by optimizing imaging techniques. It is essential
to communicate findings clearly to both referring physicians and patients. Additionally,
the radiologist should engage actively with the patient's clinical context to ensure
the most relevant imaging studies are performed, all while considering the patient's
individual needs and concerns as the primary focus.
Imaging Modalities
Pelvic Radiograph (X-Ray)
Conventional radiography is not usually the primary screening modality in infertility;
however, occasionally, pelvic radiographs may give some clue in cases of underlying
pathology. Calcifications in old fibroids or adnexal masses may be incidentally detected.
Hysterosalpingography
Hysterosalpingography (HSG) is mainly indicated for tubal pathologies and patency.
Mullerian anomalies, tubal blocks, uterine synechiae, and cervical stenosis can also
be diagnosed on HSG.[3] This procedure is done in the lithotomy position. The cervical external os is visualized
via Sims vaginal speculum and catheterized using 6-Fr Foley catheter or Leech Wilkinson
cannula. High-osmolar iodinated contrast medium is then injected to visualize the
uterine cavity and fallopian patency, seen as free peritoneal spill under fluoroscopy.
HSG is ideally done between the 1st and 14th days of a normal cycle.[4] It is contraindicated in patients with pelvic inflammatory disease (PID) and recent
dilation and curettage (D&C). The complications include allergy to contrast, tubal
spasm, vasovagal syncope, iatrogenic trauma to the cervix or uterus, and infection.
Its main pitfall is that extraluminal pathology cannot be identified, and the efficacy
of the procedure is often operator-dependent.[5]
Pelvic Ultrasonography: Transabdominal and Transvaginal
Ultrasonography (USG) is the simplest, safest, radiation-free, real-time imaging of
pelvic organs. It is useful in detecting various adnexal, uterine, ovarian, cervical,
and ovarian pathologies and is usually the first screening modality in female infertility.
It can be performed anytime, irrespective of the cycle. A full bladder improves the
transabdominal evaluation. Combined with a Doppler scan, the vascularity of structures
can also be assessed. The major pitfalls are operator dependency, patient body habitus,
complex pathologies involving multiple structures, air and calcium impeding visualization,
and inability to obtain images in the surgical plane.
Sono-Hysterosalpingography (Saline Infusion Sonogram)
Sono-HSG is the technique of USG-guided saline-infused visualization of the uterine
cavity and fallopian tubes. It is specifically indicated in cases of endometrial pathologies
such as polyps, submucosal fibroids, synechiae, congenital anomalies, and tubal patency.
It is performed under a lithotomy position. The external os is cannulated via the
Jarcho cannula or 8-Fr Foley/uterine catheters and saline injected, to visualize the
uterine cavity and look for spill in pelvis to confirm tubal patency ([Fig. 2]). The same procedure, done under color Doppler, can improve visualization of the
spill and help in localization.[4] The first step is to adequately distend the endocervical and endometrial canals
to look for any pathology ([Fig. 3]).
Fig. 2 Instruments used in SIS: (A) Jarcho cannula, (B) elliptosphere balloon catheter, (C) Goldstein intrauterine catheter.
Fig. 3 Longitudinal SIS images of the lower uterine segment show adequate distention of
the endocervical canal (arrows). During this phase, it is critical to observe for
over- or under-distention of the endocervical canal.
A modification of the procedure is called the air–saline technique, which involves
a transvaginal approach. The TVS probe is oriented in the transverse plane to demonstrate
both uterine cornua. The air and saline mixture is injected, and a dynamic assessment
of the quick forward movement of the echogenic air–saline mixture from the endometrial
cavity through the interstitial fallopian tubes is visualized. This technique is good
for enhancing the tubal visualization and localizing the site of pathology. The patent
tubes will show fimbrial turbulence and a “waterfall sign” because of free spillage.
Major pitfalls include identifying tubal spasm versus occlusion, locating the exact
site of tubal pathology, and diagnosing intratubal pathology and peritubal adhesions.
However, the major advantages of saline-infusion sonogram (SIS) are that it is real-time,
radiation-free, less painful, and allows simultaneous assessment of the uterus, ovaries,
and adnexa.[3]
[4]
Computed Tomography
The indications for CT are to stage ovarian malignancies and to characterize ovarian
lesions, especially in patients with contraindications for MRI, although CEMRI is
the preferred modality.
Magnetic Resonance Imaging
MRI is the modality of choice for the evaluation of infertility. It is safe, non-ionizing,
and provides excellent soft tissue resolution with multiplanar imaging of structures.
With contrast and dynamic MRI imaging, further evaluation and characterization of
lesions are feasible.
A contrast-enhanced MRI of the brain and Sella can be done to rule out central/hormonal
causes of infertility. When it comes to visualizing ovarian, uterine, and adnexal
diseases, MRI offers exceptional resolution and helps in distinguishing between various
Mullerian duct abnormalities. The accurate diagnosis and differentiation of leiomyoma
and adenomyosis is possible. It is excellent for imaging and follow-up of deep pelvic
endometriosis, as the results of conservative treatment can be evaluated, thus helping
to decide a more effective treatment plan. MRI also serves as an adjunct to HSG and
diagnostic laparoscopy in patients with adnexal pathologies and endometriosis-related
hydrosalpinx, peritubal, or pelvic adhesions.[5]
[6] The major pitfalls of MRI include cost, availability, longer acquisition time, movement
artefacts, claustrophobia, and the presence of MRI-unsafe implants.[6]
Advanced Imaging Modalities
Advanced Imaging Modalities
Hysterosalpingo-Contrast Sonography
When SIS is performed using the ultrasound contrast agent Sonovue (SF6 microspheres),
it is termed “hysterosalpingo-contrast sonography (HyCoSy).” Approximately 0.5 to
1 mL of contrast is diluted in 10 to 15 mL of saline and agitated to form a foamy
mixture. It is then instilled in the uterine cavity, and three-dimensional (3D) visualization
is done. The advantages are assessment of the entire fallopian tube, the exact site
of tubal block with the use of a safe contrast agent, and a radiation-free imaging
modality. However, the cost and short shelf life of the contrast are a few major pitfalls.[4]
[7]
Hysterosalpingo-Foam Sonography
Hysterosalpingo-foam sonography (HyFoSy) is the term used when SIS is carried out
with intrauterine foam instillation using a cervical balloon. The foam mixture is
sufficiently stable to show echogenicity in the fallopian tubes and visualize passage
through the patent tubes for at least 5 minutes. The foam is made by vigorously mixing
5 mL of sterile-purified water with 5 mL of a gel containing hydroxyethyl cellulose
and glycerol. It is non-embryotoxic and FDA-approved in the United States. The advised
dose is 2 to 3 mL, given by intrauterine infusion, and the maximum permissible dose
is 10 mL. HyFoSy has proven superior to HyCoSy in the evaluation of tubal patency,
with a high agreement of 94% with laparoscopic findings.[4]
[7]
Fertiliscan
Fertiliscan includes performing a high-quality 3D ultrasound and SIS for analysis
of the uterine cavity and tubal patency in one single sitting for the patient undergoing
evaluation for infertility. It assesses the anatomy and function of the uterus, the
ovaries, and the tubal patency in one go. It is performed at days 5 to 9 of the menstrual
cycle and acts as a one-stop shop for the patients, along with the merits of being
radiation free and minimally invasive.
Sonoelastography
Shear wave elastography is a type of dynamic real-time technique to measure the stiffness
of underlying tissue. It gives a quantitative measurement of the examined tissue ([Fig. 4]). It is a potential area of research in larger populations, and its application
can be useful in the evaluation of infertility. Endometrial elastography is an upcoming,
novel technique and a potential marker for assessing endometrial receptivity for conception
and embryo transfer. It may also predict the pregnancy outcomes based on endometrial
thickness and type. Cervix elastography can be used to evaluate inhomogeneity and
predict embryo transfer ease in infertile women undergoing in vitro fertilization
or intracytoplasmic sperm injection.[5]
[7]
Fig. 4 Ultrasound shear wave elastography of the cervix with quantitative measurements in
kilopascal.
MRI-Hysterosalpingography
MRI-hysterosalpingography (MR-HSG) is performed by injecting gadolinium (diluted with
saline in a 1:100 ratio) in the uterine cavity, followed by MRI acquisition. It helps
in the superior definition of uterine disease and anomalies, the evaluation of endometrium,
as well as myometrium. Tubal patency assessment can be done using cine images and
dynamic MRI sequences. Intratubal and extratubal diseases can be simultaneously assessed.
Tubal Causes
Congenital Tubal Anomalies
Congenital tubal anomalies are agenesis, hypoplasia, duplication, and accessory fallopian
tubes. These usually present with primary infertility with no other coexistent disease/symptoms.[6]
Acquired Tubal Pathologies
Pelvic Inflammatory Disease
PID is a broad term denoting the infection and inflammation of the female pelvic genital
tract. The most common organisms causative of PID are Chlamydia, Neisseria gonorrhoeae, and polymicrobial infection. Ascending infection may occur in the form of cervicitis,
endometritis, salpingitis, hydrosalpinx, and pyosalpinx which typically progress from
the vagina or cervix to the endometrium, fallopian tubes, and finally to neighboring
structures, causing oophoritis, tubo-ovarian abscess, and peritonitis. Ascending PID
is usually bilateral. Descending infection may occur from peritoneal or primary abdominal
disease with transserosal spread, tubercular peritonitis being the most common cause.
Descending PID is typically unilateral, caused by direct extension of appendiceal,
diverticular, or postsurgical infection/abscesses.[8]
[9]
HSG shows tubal block and peritubal adhesions as a beaded/string appearance or tobacco
pouch look ([Fig. 5]). On sonography, hydrosalpinx, pyosalpinx, thickened tubes with peritubal vascularity,
and a cog-wheel appearance due to incomplete septa are seen. CT scan usually reveals
a complex tubo-ovarian mass, pelvic soft tissue stranding, uterosacral ligament thickening,
and adherent pelvic organs. Fallopian tube thickness of more than 5 mm is considered
significant. MRI can provide better delineation and contrast enhancement of these
structures. Diffusion restriction accurately detects early pyogenic contents in the
tubes and adnexa ([Fig. 6]). The complications of PID include diffuse peritonitis, ectopic pregnancy, ovarian
vein thrombosis, and pelvic or peritoneal adhesions.
Fig. 5 HSG showing irregular tubal outline with tiny diverticula (blue arrow). Irregular
borders and beaded appearance in both the fallopian tubes, with obstruction at the
distal isthmic portion with a “golf club” appearance (orange arrow). No peritoneal
spillage is seen on the left side (blue star). Findings suggestive of genitourinary
tuberculosis.
Fig. 6 A 33-year-old female with secondary infertility, pelvic pain, and vaginal discharge.
(A, B) USG showing bilateral complex adnexal masses with increased vascularity (green arrow).
(C) T2WI show heterogeneous contents, debris, and peripherally displaced residual ovarian
stroma.(yellow arrow) (D) Postcontrast T1FS images show thick, irregular rim enhancement, suggestive of bilateral
tubo-ovarian abscesses (blue arrow) and adherent bowel loops (marked as a). Pelvic
inflammatory disease.
Tuberculosis is a prevalent disease affecting the Indian population, with genitourinary
tuberculosis responsible for 25 to 30% of cases of extrapulmonary tuberculosis and
causing infertility. Differentiating tuberculosis from pyogenic infection is important
for appropriate treatment initiation.[9]
[10] These differentiating imaging features are tabulated in [Table 1].
Table 1
Imaging findings differentiating PID and TB
|
Imaging findings
Commonplace in PID and TB
|
Imaging findings
Discerning TB from PID
|
|
Fallopian tubes
|
Hydrosalpinx: dilated tubular structure
Pyosalpinx: dilated tubular structure with echogenic debris and peri-tubal adhesions
DW MRI shows restriction
|
USG: presence of peripheral echogenic foci in the tubes (calcifications due to tubercular
granulomas)
T2WI hypo intensity and blooming on GRE
|
|
Ovaries
|
Oversized with increased stromal echogenicity due to edema
|
Adnexal calcifications
|
|
Uterus
|
Adhesions in the endometrial cavity
|
Endometrial calcifications, along with adhesions and hazy parametrium
|
|
Others
|
Pelvic vascular congestion
Adhesions and pelvic free fluid
|
Calcified lymph nodes
Peritoneal thickening, omental caking, misty mesentery, peritoneal free fluid
Severe adhesions
|
Salpingitis isthmica nodosa: A condition with multiple tiny nodular outpouchings from the fallopian tubes, commonly
occurring at the isthmic segment. It is said to be due to benign invaginations of
tubal epithelium into the myosalpinx. It is usually bilateral (85% of cases) and highly
associated with infertility and ectopic pregnancy. Imaging will show multiple contrast-filled
outpouchings or diverticula from the fallopian tube, which is best demarcated on HSG
([Fig. 7]).
Fig. 7 HSG showing tubal irregularity. Multiple contrast-filled luminal pouches projecting
2–3 mm outward from the isthmic portion of both fallopian tubes (blue arrows). Findings
suggestive of salpingitis isthmica nodosa.
Endometriosis–related hydro/hematosalpinx: Endometriosis will cause tubal and peritubal adhesions, hydrosalpinx, and hematosalpinx
with an increased risk of tubal ectopic pregnancy ([Fig. 8]).
Fig. 8 USG TVS showing a large complex right tubo-ovarian lesion. (A) Right ovarian endometrioma with typical ground-glass homogenous echoes (blue arrow)
and adjacent dilated tube with contents, suggestive of hematosalpinx (yellow arrow).
(B) Ovarian endometrioma with associated hematosalpinx (blue star).
Prior tubal ectopic and surgery: Salpingectomies/salpingostomies also present with tubal blocks and are a common cause
of secondary infertility.[9]
[10]
Uterine Causes
Mullerian Anomalies
The mullerian ducts are paired embryologic structures that fuse and resorb to form
the fallopian tubes, uterus, cervix, and upper two-thirds of the vagina. Any variations
occurring during development may lead to different anomalies, broadly classified as:
-
Developmental defects: can present with bilateral agenesis/hypoplasia ([Fig. 9]) or unilateral unicornuate uterus (look for a noncommunicating rudimentary horn
with/without endometrium) ([Fig. 10]).
-
Fusion defects: If complete, present as uterus didelphys, usually with an associated transverse
hemivaginal septum ([Fig. 11]). If incomplete, it manifests as a bicornuate uterus (with a surface cleft >1 cm;
[Table 2]). The uterine cavities may or may not communicate.
-
Reabsorption defects: Usually present as a septate uterus with fibrous or myometrial signal intensity.
The external fundal contour is convex with a partial or complete septum (independent
or communicating cavities) ([Fig. 12]).
Fig. 9 Ultrasound images (A) show an anteverted uterus with hematometra. (B) An atretic cervix and vagina. (C, D) Bilateral adnexa with dilated fallopian tube and hematosalpinx. MRI images (E, F). T2W axial and sagittal images show hypointense content within the endometrium and
bilaterally dilated fallopian tubes. Hypoplastic cervix, atretic vagina. (G) Axial T1W content appears hyperintense. (H) T2* GRE showing areas of blooming in the left dilated fallopian tubes, suggestive
of blood products.
Fig. 10 A 22-year-old woman with a history of dysmenorrhea. (A) TAS: Left-sided hypoechoic collection, separate from the ovary (yellow arrow) (B) Transperineal USG: a hypoechoic tract with hyperechoic mural lining (arrowhead) between
the urethral and anal opening (blue arrows); atretic vaginal canal. (C) Right unicornuate uterus with normal endo-myometrial junction. Left-sided rudimentary
horn with no communication with the right-sided cavity (yellow arrow). (D) Hematometra in the sequestered horn, with communicating hematosalpinx (yellow arrow).
(E) A rudimentary blind-ending vagina in the upper one-third (arrow). (F) Left renal agenesis (star). Final diagnosis: Right-sided unicornuate uterus with
left-sided functional rudimentary horn with left hematometra and hematosalpinx. ESHRE
classification--U4a C3V4.
Table 2
Mullerian anomalies: differentiating imaging features
|
Mullerian anomaly
|
Bicornuate uterus
|
Septate uterus
|
Arcuate uterus
|
|
|
|
|
|
External uterine contour (EUC)
Intercornual line (IC line)
|
Apex of EUC is below the IC line or <5 mm above the IC line
|
Apex of EUC is >5 mm above the IC line
|
EUC is normal
Indentation on the fundal myometrium
|
|
Intercornual distance
|
>4 cm
|
<4 cm
|
Increased transverse diameter of the uterus
|
|
Intercornual angle
|
>105°
|
75°
|
No division of the uterine horns
|
|
Fundal cleft
|
>1 cm
|
<1 cm
|
No fundal cleft
|
|
Additional features
|
Longitudinal vaginal septum in 25% cases
|
Fibrous or muscular
Complete or partial
|
Mimics: uterine fibroid or focal adenomyosis
|
Fig. 11 A 24-year-old married female with primary amenorrhea. (A, B) The endometrial cavity is distended with T1/T1FS bright contents, suggestive of hematometra.
(C) The cervix is also distended; bright on T1/T1FS (hematocolpos) (yellow arrow)—a thick
hypointense septum (3.5 mm) at the upper endocervical canal level, separating hematometra
and hematocolpos (arrowhead)—a T2 hypointense septum (2.7 mm) at the junction of the
upper vagina and cervix. ESHRE classification—U0 C1 V3.
Fig. 12 A 32-year-old female with primary infertility. (A) Myometrial indentation >50%. (yellow line). (B) A septum completely divides the uterine cavity and reaches the internal os. (thin
yellow arrow). Complete septate uterus with a septate cervix (fibromuscular septum).
U2b C1 V0 as per ESHRE classification.
MRI is the imaging modality of choice for these uterine anomalies. These are usually
associated with genitourinary abnormalities and syndromes such as the Mayer–Rokitansky–Hauser
syndrome and the Zinner syndrome, which can be simultaneously looked for during the
study ([Fig. 13]).[10] The American Society for Reproductive Medicine (ASRM) classifies Mullerian anomalies
into nine groups, as updated in 2021.[11] The European Society of Human Reproduction and Embryology (ESHRE) and the European
Society for Gynecological Endoscopy (ESGE) classify these anomalies based on anatomy.
The classification system is based on the embryological origin of the anomalies and
annotates point system based on the degree of development to the uterus (U0–U6), cervix
(C0–C4), and vagina (V0–V4).[12]
Fig. 13 A 20-year-old woman presenting with primary amenorrhea; normal breast development.
(A, B) Absent kidneys in bilateral renal fossa (yellow stars) Pelvic kidney (green arrow)
with absent uterus, cervix, and vagina. (C) Bilateral normal gonads (green arrows). MRKH syndrome type 2. ESHRE classification
--U5b C4 V4. Left renal agenesis and right ectopic kidney.
Endometrial and Myometrial Pathologies
Uterine Synechiae
Uterine adhesions, also known as Asherman syndrome, occur after injury to the endometrium
and commonly lead to infertility. They result from trauma to the basal layer of the
endometrium postpregnancy, post-D&C, surgery, or infection.
Endometrial Polyp
Endometrial polyps are protrusions of the normal endometrium into the uterine cavity.
They begin as benign protrusions, but over long-standing may undergo metaplasia and
malignant transformation into endometrial carcinoma. They usually occur in hyperestrogenic
states, patients receiving tamoxifen, endometriosis (2.8-fold increased risk), multiparity,
and chronic cervicitis. The usual presenting clinical symptom is abnormal uterine
bleeding as metrorrhagia. The presence of a polyp impedes implantation and hence causes
infertility.[5]
[7]
[9]
On USG, they appear as an echogenic focus within the endometrial cavity with focal
endometrial discontinuity at the stalk (in pedunculated polyps) and vascular pedicle.
Sessile polyps may also occur with diffuse vascularity. The feeding vessel sign is
often diagnostic. On MRI, their signal characteristics are similar to those of the
endometrium ([Fig. 14]).
Fig. 14 A 34-year-old woman with secondary infertility. (A, B) Pedunculated heterogeneously iso-hyperechoic mass arising from the fundus region
with cystic areas within, splaying the two linings of endometrium with a maintained
endometrial–myometrial junction throughout. (D) There is a single pedicle artery seen within the stalk. (C, E) MR images display signal characteristics like endometrium with cystic changes. Pedunculate
endometrial polyp.
Adenomyosis
Adenomyosis is the presence of ectopic endometrial glands within the myometrium, with
surrounding smooth-muscle hyperplasia. USG usually shows an indistinct junctional
zone, sub-endometrial echogenic linear striations, and/or nodules (specific sign)
extending from the endometrium and into the inner myometrium, hyperechoic islands,
sub-endometrial cysts (specific sign), and myometrial hyperplasia, appearing as a
bulky myometrial wall. A “Venetian blind” or “rain shower” appearance (linear striations,
parallel shadowing) may be seen as a constellation of the above findings. MRI is more
specific and sensitive for the diagnosis of adenomyosis. Diffuse or focal thickening
of the junctional zone, a T2-weighted (T2W) low-signal-intensity layer at the deep
myometrium, is highly specific, and a junctional zone thickness of >12 mm is significant.[9]
[10]
As of 2021, the consensus on updated definitions of the Morphological Uterus Sonographic
Assessment (MUSA) features of adenomyosis divides the signs of adenomyosis into two
categories. Direct signs include myometrial cysts, hyperechogenic islands, and echogenic
sub-endometrial lines/buds. Indirect signs include a globular uterus, fan-shaped shadowing,
translesional vascularity, irregular junctional zone, asymmetrical myometrial thickening,
irregular junctional zone, interrupted junctional zone, and irregular junctional zone.[13]
On T2W image (T2WI), areas of adenomyosis show ill-defined low-signal intensity foci,
which are embedded within a hyperintense area, which depicts ectopic endometrial tissue
islands and cystic gland dilatation. When menstrual bleeding develops in this ectopic
endometrial tissue, T1WI will show high-signal-intensity foci. The appearance of these
bright foci on T1 and T2WI confirms the diagnosis of adenomyosis. As an endometrial
tissue with hormonal influence, its imaging appearance varies depending on the cycle
phase and treatments.[8]
[10] Adenomyoma is a poorly demarcated lesion embedded within the myometrium and is separate
from the junctional zone ([Fig. 15]). It may mimic a uterine fibroid. It follows the same signal characteristics of
diffuse adenomyosis. Cystic adenomyosis is a cystic variant with visible sub-endometrial
and myometrial cysts.[13]
Fig. 15 A 38-year-old female with secondary infertility. (A, B) USG shows a heterogeneous lesion in the posterior myometrium. (C) Sagittal T2WI shows a poorly demarcated lesion embedded within the myometrium, separate
from the junctional zone. (D) Axial T1FS shows hemorrhage due to heterotopic endometrial tissue, suggestive of
focal adenomyoma.
Uterine fibroids, on the other hand, often have a pseudo capsule of compressed myometrial
tissue surrounding them and, hence, are well demarcated. [Table 3] depicts the differentiating imaging features of focal adenomyosis, adenomyoma, and
fibroid, which are common diagnostic challenges.
Table 3
Imaging findings differentiating myometrial pathologies
|
Myometrial pathology
|
Focal adenomyosis
|
Adenomyoma
|
Fibroid
|
|
Imaging modality
|
|
|
|
|
USG
|
Echogenic nodule with undefined margins
Cystic spaces: variable
|
Focal confluent region of adenomyosis forming an ill-defined mass, distinctly separate
from the junctional zone of the uterus
|
Well-defined myometrial mass with pseudocapsule.
Typically hypoechoic, but can be iso- or hyperechoic to myometrium. Presence of calcifications
|
|
Color Doppler
|
Penetrating vascularity
|
Penetrating vascularity
|
Peripheral vascularity (vascular pseudo capsule)
|
|
MRI
|
Thickened junctional zone with myometrial hyperplasia
|
Junctional zone may or may not be thickened
Adjacent myometrium may be normal
|
Submucosal/Intramural/Subserosal location. Normal junctional zone
|
|
T1W: hyperintense foci due to hemorrhage/ectopic endometrial glands
T1W CE: punctate enhancement
|
Same as focal adenomyosis
|
T1W: hypointense appearance
T1W CE: variable
|
|
T2W: cystic changes/flow voids within the lesion
|
Same as focal adenomyosis
|
Peripheral flow voids
Cystic degeneration may be seen
|
Uterine Fibroid
Fibroid is one of the most common pathologies affecting the myometrium. Submucosal
and pedunculated fibroids are notorious for causing infertility. They are benign tumors
of the myometrium. If long-standing, they show popcorn calcification on X-ray. On
USG, they appear as well-defined hypoechoic lesions within the myometrium. On MRI,
they appear as well-demarcated lesions, appearing iso- to hypointense on T1 and T2WI
with variable contrast enhancement and perilesional flow voids (specific sign). Based
on the occurrence within the myometrium, from submucosal to subserosal location, they
are classified by the International Federation of Gynecology and Obstetrics (FIGO)
into eight types.[14] Among these, the FIGO type 0 (pedunculated submucosal intracavitary fibroid) might
be responsible for infertility as it impedes embryo implantation in the endometrial
cavity ([Fig. 16]).
Fig. 16 A 30-year-old female presented with infertility, menorrhagia, and lower abdominal
pain. (A, B) TVS shows a large pedunculated mass arising from the fundoposterior wall with distortion
of the endometrial–myometrial junction, prolapsing up to the lower endometrial segment
cavity with rim type of vascularity along with multiple internal vessels. (C, D) T2W sagittal and coronal images show a lobulated bulky lesion prolapsing into the
endometrial cavity, connected to myometrium by a long stalk, and give a “broccoli-like”
appearance suggestive of prolapsed submucosal fibroid.
The fibroids may undergo various degenerations like hyaline (low signal on T2WI),
myxoid, cystic (both high signal on T2W), and red (high signal on T1WI). The lipo-leiomyoma
variant contains fat within, appearing hyperintense on USG and hyperintense on T1WI.
The complications include torsion of subserosal fibroid, prolapse of submucosal fibroid
into the endometrial cavity, malignant degeneration, and red degeneration in pregnancy.[9]
[10]
[14]
Cervical and Vaginal Pathologies
Cervical stenosis, which may be congenital or secondary to cervicitis (infection),
can cause infertility. In rare cases, cervical cancer may occur in young women (human
papillomavirus-associated adenocarcinoma) and may cause infertility. Vaginal stenosis,
transverse/longitudinal vaginal septum, presenting with or without mullerian anomalies
may cause primary infertility.[9]
Ovarian Disorders
Ovarian lesions that can cause infertility primarily include cysts associated with
conditions like polycystic ovary syndrome (PCOS) and endometriosis, where particularly
“chocolate cysts” (endometriomas) can disrupt ovulation, block fallopian tubes, and
cause pelvic adhesions. Large or complex ovarian cysts can also interfere with ovulation
and potentially cause fertility issues, depending on their size and location.[15]
Polycystic Ovarian Syndrome
PCOS is a condition caused by hormonal imbalance, where there is a hyperandrogenic
state causing anovulatory cycles and, hence, difficulty in conceiving. The 2018 International
Evidence-based Guideline criteria (based on the 2003 Rotterdam criteria, updated in
2023) is used to make the diagnosis of PCOS after exclusion of other etiologies (central/adrenal
causes) and require at least two of the following: ovulatory dysfunction (oligo- and/or
anovulation), clinical and/or biochemical signs of hyperandrogenism, polycystic ovarian
morphology on ultrasound/elevated serum anti-Mullerian hormone.[16]
Hence, an ultrasound is not necessary for the diagnosis if the other two criteria
are met. On USG, the updated diagnostic criteria for polycystic ovarian morphology
based on a 2023 international consensus guideline are as follows:
In patients >8 years post-menarche: follicle number per ovary (FNPO) ≥20 in at least
one ovary (considered the most accurate ultrasound finding) or if image quality is
insufficient for a complete follicle count then at least one of the following, follicle
number per section ≥10 in at least one ovary, and/or ovarian volume ≥10 mL, without
corpus luteum/dominant follicle. FNPO should include any follicles measuring 2 to
9 mm. Other ovarian pathologies, including ovarian cysts, corpus luteum, should not
be included in ovarian follicle counts or volume calculations.
In adolescent females (defined as within 8 years of menarche, or age <20 years), ultrasound
should not be used for the diagnosis of PCOS due to the high incidence of multifollicular
ovaries in this life stage. Other ancillary findings not included in the diagnostic
criteria are increased central echogenic stroma and peripherally arranged follicles.[15]
[16] MRI findings are like those of USG; they provide better multiplanar resolution and
volume measurements.
Endometriosis
Endometriosis is the ectopic presence of endometrial tissue beyond the uterine cavity.
It is an estrogen-dependent disease, affecting approximately 10% of the population,
exclusively in women of the reproductive age group. Seventy percent to 80% of women
with severe endometriosis have difficulty conceiving.[1]
[9] Multiple theories have been proposed for its occurrence: metastatic theory (retrograde
implantation of endometrial tissue via fallopian spill), metaplastic theory (de-differentiation/metaplasia
of serosal surfaces), and the induction theory (secondary induction of undifferentiated
mesenchyme into endometriotic tissue), of which the most accepted is the metastatic
theory.[17] The pelvis should be compartmentalized to better localize the endometriotic pathology
and describe its extent.
-
Anterior compartment includes the prevesical recess, bladder, distal ureters, urethra,
vesicouterine pouch, and the vesicovaginal septum. The distal ureter and bladder trigonal
region are important for identification and reporting, and a urologist is required
during surgery. When there is a history of cyclical hematuria, bladder mucosal endometriosis
should be looked for diligently.
-
Middle compartment includes the broad ligament, uterus, fallopian tubes, ovaries,
meso-ovarium, pelvic lateral wall, and vesicouterine and rectouterine folds.
-
Posterior compartment includes rectovaginal pouch and septum, retrocervical area,
or the torus uterinus, uterosacral ligaments, posterior vaginal fornix, and the rectum.
The identification and location of serosal endometriosis deposits in the middle and
posterior compartments must be documented since they cause adhesions and make the
laparoscopic approach difficult.
Extrapelvic endometriosis—Intraperitoneal involvement, interbowel loops, ischioanal
fossa, and rarely sciatic nerve, presenting as cyclical sciatica.[18]
[19]
Imaging Features of Endometriosis
Ovarian Endometriomas
Endometriomas, or chocolate cysts, are ectopic ovarian endometriosis. On ultrasound,
these cysts show low-level internal echoes and a ground-glass appearance. They may
show papillary projection and undergo decidualization during pregnancy and hence mimic
malignancy. On MRI, solitary/multiple cysts may be seen showing homogeneous high-signal
intensity on T1 and T1FS images. T2W signal varies according to the age of bleeding
and may show a typical stratified appearance (shading sign) because of cyclic bleeding
with blood products accumulating over months ([Fig. 17]). In some cases, dark spots may be visible within these cysts, the T2 dark spot
sign, which is specific for endometriosis. Bilateral ovarian endometriosis, with adhesions
and medialization of ovaries in the adnexa, known as kissing ovaries, is also specific
for endometriosis.[9]
[17]
[18]
Fig. 17 A 27-year-old female patient presented with primary amenorrhea and infertility. (A) Sagittal T2WI shows non-visualization of the normal uterus and upper two-thirds of
the vagina in midline (star). (B) Coronal T2WI showing bilateral uterine buds with three-layer differentiation (arrows).
(C) Linear fibrous bands connecting the two uterine buds (star). (D) Axial T2WI showing a sizeable, well-defined lesion in the right adnexa with T2 shading,
suggesting an endometriotic cyst (star). (E) Another smaller endometriotic deposit in the right adnexa (star) with dilated right
fallopian tube (arrow). (F) Normal left ovary (arrow).
Superficial Endometriosis
Multiple superficial plaques are scattered across the peritoneum, ovaries, and uterine
ligaments, known as Sampson syndrome. This syndrome is associated with less severe
symptoms, fewer pelvic structural changes, and substantially less risk of major complications.[20] MRI is useful in lesions >5 mm, which usually appear hyperintense on T1WI, hypointense
on T2WI, and show blooming on gradient sequences (GREs), suggestive of hemorrhagic
deposits.[19]
Deep-Infiltrating Endometriosis
These deposits are usually difficult to visualize on USG due to their location; however,
they may appear as hyperechoic lesions (if acutely hemorrhagic) at the rectouterine
pouch or the cul-de-sac. Due to adhesions, they are usually accompanied by a retroverted
uterus, termed as a “question mark sign.” The uterovesical pouch may be obliterated
and elicits a positive sliding sign on transvaginal ultrasound. Cullen's syndrome
can be used to describe those patients with severe symptoms and palpable pelvic nodules
of endometriosis. These patients usually do not respond to medical therapy and require
extensive surgery.[20]
On MRI, they appear as pelvic nodules or plaque-like lesions composed of endometrial
glands and stroma surrounded by a thick fibromuscular and inflammatory reaction. They
have an irregular, spiculated shape, with intermediate signal on T1WI and low-signal
intensity on T2WI. If hemorrhagic, these may show focal areas of blooming on GRE.
Small hyperintense foci corresponding to endometrial glands are almost always recognized
within the endometriotic nodules in both T1 and T2WI. The most common site for DIE
is the posterior pelvic compartment, where all anatomic structures bordering the pouch
of Douglas can be involved. Thickened uterosacral ligaments > 6 mm and tethering of
rectum to the posterior uterus, also termed as “teardrop rectum,” are highly specific
signs.[17]
[19]
Bowel Endometriosis
Bowel involvement is diagnosed when nodular or plaque-like bowel wall thickening is
seen with loss of the fat tissue plane between the intestinal loop and the uterus
or other adjacent organs. Signal characteristics are the same as other endometriotic
deposits. The diagnosis may be supported by a “mushroom cap” sign and represents the
endometriotic nodule growing into a mushroom-like shape in the bowel wall, covered
by a high-intensity signal rim representing the normal mucosa and submucosal layer,
specific for endometriosis.[9]
[10]
Cystic Ovarian Lesions
Cystic ovarian lesions are a broad term encompassing both benign and malignant lesions.
Any large lesion compromising the ovarian stroma may impede normal ovarian function
and cause infertility. The evaluation with serum tumor markers, USG, and MRI will
lead to the diagnosis.
An imaging algorithm for the evaluation of female infertility has been suggested ([Fig. 18]).
Fig. 18 Approach to a case of infertility.
Imaging in Male Infertility
Imaging in Male Infertility
The male is solely responsible for about 20% of cases and is a contributing factor
in another 30 to 40% of all infertility cases. Evaluation of male infertility involves
a detailed sexual history and physical examination, together with two separate semen
analyses. If anomalies are discovered, hormonal tests and an optional scrotal ultrasound
can be carried out. This is typically adequate to determine the type and severity
of the underlying problem. The key purpose of evaluating a male for infertility is
to identify the contributing factors and offer treatment for those that are reversible.
Causes of male infertility can be classified as pretesticular, testicular, posttesticular,
and adjacent pathologies. Among them, the reversible causes include infection, obstructive
azoospermia, and benign lesions of the testis. The role of imaging in male infertility
includes identifying sperm production or function, identifying any obstruction in
the pathway of delivery of sperm, and aiding in methods for impregnating the female
partner by image-guided sperm aspiration.
Ultrasound
Ultrasound is the primary screening modality for imaging male infertility. USG scrotum
can be done to assess testicular volume, vascularity, testicular torsion, infectious
orchitis, epididymo-orchitis, and prostatitis. Penile Doppler can be done to assess
the arterial and venous insufficiency causes of erectile dysfunction. Transrectal
USG is done to assess prostatic pathologies, evaluate seminal vesicle size and volume,
and check ejaculatory duct status.
MRI Scrotum and Prostate
MRI is useful in cases of ectopic/undescended testis and helps in the localization
of the same. Benign or malignant testicular tumors can be better assessed and evaluated
on MRI. Multiparametric MRI of the prostate and the advent of the prostate imaging
and reporting data system (PIRADS) have improved the visualization, evaluation, and
reporting of prostatic nodules. MRI of the brain is useful for central causes, hypogonadotropic
hypogonadism, and pituitary causes.
Conclusion
Infertility is a common but serious problem since, apart from medical issues, it has
a significant psychosocial impact on the couple. With the advances in medical science,
women are increasingly undergoing evaluation to determine any treatable etiology.
Here comes the role of imaging, which is crucial for reaching a diagnosis and managing
the patient. HSG and USG are the initial investigations of choice, which assess the
tubal patency and any structural anomaly. SIS is a good alternative, leading to the
combined assessment of tubes, the uterus, and ovaries in a single study. Fertiliscan
further integrates 3D USG and SIS as a one-stop shop. Upcoming advances in imaging
with the use of contrast in SIS and MR HSG are expanding the radiologist's horizon
to administer the best care in the patient's interest.
