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DOI: 10.1055/s-0045-1809653
Imaging Approach to Infertility
Funding This research did not receive any financial grant from funding agencies in the public or commercial sectors.
- Abstract
- Introduction
- Imaging Modalities
- Advanced Imaging Modalities
- Tubal Causes
- Uterine Causes
- Imaging in Male Infertility
- Conclusion
- References
Abstract
This review highlights the role of imaging in the evaluation of female infertility. The multifactorial origin, role of different imaging modalities, and key imaging findings are emphasized. It features all the tubal, uterine, cervical, vaginal, and ovarian pathologies accounting for female infertility and detected by imaging. The role of hysterosalpingography (HSG), pelvic ultrasound (USG), sono-HSG, and magnetic resonance imaging (MRI) of the female reproductive tract is discussed. In addition, the advances in imaging, including contrast-enhanced sono-HSG, sonoelastography, and MR HSG are reviewed. Though hysterolaparoscopy is the gold standard, USG is usually the first-line investigation, and MRI expands the frontiers of knowledge due to its enhanced soft-tissue resolution and multiplanar imaging capabilities. Though the initial clinical evaluation of infertility lays stress on serum hormonal evaluation and detecting ovulation, imaging plays a pivotal role in evaluating certain causes confined to the uterus or ovaries. The need of the hour is to develop an all-inclusive, integrated imaging strategy for the evaluation of female infertility. The current proposal is to combine Fertiliscan, a combination of high-quality 3D USG and assessment of tubal patency by sono-HSG and MR HSG, to look for detailed anatomy in one go. Nevertheless, exhaustive research is needed to establish their reliability, safety, and cost-effectiveness, especially in the resource-limited settings of Southeast Asia.
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.
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]).
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
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]
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.
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].
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]).
Endometriosis–related hydro/hematosalpinx: Endometriosis will cause tubal and peritubal adhesions, hydrosalpinx, and hematosalpinx with an increased risk of tubal ectopic pregnancy ([Fig. 8]).
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:
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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]).
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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.
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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]).
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]
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]).
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]
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.
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]).
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.
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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.
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Middle compartment includes the broad ligament, uterus, fallopian tubes, ovaries, meso-ovarium, pelvic lateral wall, and vesicouterine and rectouterine folds.
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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]
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]).
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.
Conflict of Interest
None declared.
Acknowledgments
We thank the staff in the Department of Radiodiagnosis, VMMC, Safdarjung Hospital, for their support and cooperation throughout the study. All subjects were acknowledged for their participation in this research.
Ethics Approval and Consent to Participate
A written approval was obtained from the participant.
Consent for Publication
The authors consented to the submission of the manuscript and publication. The authors disclosed no competing interests and no relevant relationships.
Availability of Data and Materials
The cases and the images are available from the Department of Radiodiagnosis, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India.
Authors' Contributions
N.B. is the corresponding author and designed and revised the work, interpreted the data, and submitted the case. N.B. has approved the submitted version for publication. A.A.J. and N.B. drafted the work and approved the submitted version for publication. R.M. has revised the manuscript and approved the submitted version for publication. R.M. and A.B. have revised the work. No disclosure. All authors read and approved the final manuscript.
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- 9 Sadow CA, Sahni VA. Imaging female infertility. Abdom Imaging 2014; 39 (01) 92-107
- 10 Woodward PJ, Wagner BJ, Farley TE. MR imaging in the evaluation of female infertility. Radiographics 1993; 13 (02) 293-310
- 11 Pfeifer SM, Attaran M, Goldstein J. et al. ASRM Müllerian anomalies classification 2021. Fertil Steril 2021; 116 (05) 1238-1252
- 12 Grimbizis GF, Gordts S, Di Spiezio Sardo A. et al. The ESHRE/ESGE consensus on the classification of female genital tract congenital anomalies. Hum Reprod 2013; 28 (08) 2032-2044
- 13 Van den Bosch T, Dueholm M, Leone FP. et al. Terms, definitions and measurements to describe sonographic features of myometrium and uterine masses: a consensus opinion from the Morphological Uterus Sonographic Assessment (MUSA) group. Ultrasound Obstet Gynecol 2015; 46 (03) 284-298
- 14 Gomez E, Nguyen MT, Fursevich D, Macura K, Gupta A. MRI-based pictorial review of the FIGO classification system for uterine fibroids. Abdom Radiol (NY) 2021; 46 (05) 2146-2155
- 15 Legendre G, Catala L, Morinière C. et al. Relationship between ovarian cysts and infertility: what surgery and when?. Fertil Steril 2014; 101 (03) 608-614
- 16 Hoeger KM, Dokras A, Piltonen T. Update on PCOS: consequences, challenges, and guiding treatment. J Clin Endocrinol Metab 2021; 106 (03) e1071-e1083
- 17 Coutinho Jr A, Bittencourt LK, Pires CE. et al. MR imaging in deep pelvic endometriosis: a pictorial essay. Radiographics 2011; 31 (02) 549-567
- 18 Rousset P, Florin M, Bharwani N. et al; ENDOVALIRM Group. Deep pelvic infiltrating endometriosis: MRI consensus lexicon and compartment-based approach from the ENDOVALIRM group. Diagn Interv Imaging 2023; 104 (03) 95-112
- 19 Lorusso F, Scioscia M, Rubini D. et al. Magnetic resonance imaging for deep infiltrating endometriosis: current concepts, imaging technique and key findings. Insights Imaging 2021; 12 (01) 105
- 20 Garry R. Is insulin resistance an essential component of PCOS? The endometriosis syndromes: a clinical classification in the presence of aetiological confusion and therapeutic anarchy. Hum Reprod 2004; 19 (04) 760-768
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Article published online:
12 June 2025
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- 11 Pfeifer SM, Attaran M, Goldstein J. et al. ASRM Müllerian anomalies classification 2021. Fertil Steril 2021; 116 (05) 1238-1252
- 12 Grimbizis GF, Gordts S, Di Spiezio Sardo A. et al. The ESHRE/ESGE consensus on the classification of female genital tract congenital anomalies. Hum Reprod 2013; 28 (08) 2032-2044
- 13 Van den Bosch T, Dueholm M, Leone FP. et al. Terms, definitions and measurements to describe sonographic features of myometrium and uterine masses: a consensus opinion from the Morphological Uterus Sonographic Assessment (MUSA) group. Ultrasound Obstet Gynecol 2015; 46 (03) 284-298
- 14 Gomez E, Nguyen MT, Fursevich D, Macura K, Gupta A. MRI-based pictorial review of the FIGO classification system for uterine fibroids. Abdom Radiol (NY) 2021; 46 (05) 2146-2155
- 15 Legendre G, Catala L, Morinière C. et al. Relationship between ovarian cysts and infertility: what surgery and when?. Fertil Steril 2014; 101 (03) 608-614
- 16 Hoeger KM, Dokras A, Piltonen T. Update on PCOS: consequences, challenges, and guiding treatment. J Clin Endocrinol Metab 2021; 106 (03) e1071-e1083
- 17 Coutinho Jr A, Bittencourt LK, Pires CE. et al. MR imaging in deep pelvic endometriosis: a pictorial essay. Radiographics 2011; 31 (02) 549-567
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- 19 Lorusso F, Scioscia M, Rubini D. et al. Magnetic resonance imaging for deep infiltrating endometriosis: current concepts, imaging technique and key findings. Insights Imaging 2021; 12 (01) 105
- 20 Garry R. Is insulin resistance an essential component of PCOS? The endometriosis syndromes: a clinical classification in the presence of aetiological confusion and therapeutic anarchy. Hum Reprod 2004; 19 (04) 760-768