Which test is usually performed first to evaluate tubal patency?

Hysterosalpingography (HSG) is commonly used as an initial screening procedure because it is widely available, relatively quick, and provides detailed radiographic images of the uterine cavity and fallopian tubes.

How accurate are ultrasound‑based tests like HyCoSy compared with HSG?

HyCoSy shows comparable sensitivity and specificity to HSG for detecting proximal tubal obstruction, though its ability to assess distal tubal disease may be slightly lower; accuracy depends on examiner expertise and the specific contrast agent used.

Are there any risks associated with laparoscopy and chromopertubation?

Laparoscopy carries typical surgical risks such as bleeding, infection, or injury to nearby organs, and requires general anesthesia; however, it provides the most direct assessment of tubal anatomy and function.

Can MR‑HSG be used if a patient is allergic to iodine‑based contrast?

Yes, MR‑HSG typically employs gadolinium‑based or water‑based contrast agents, making it a suitable alternative for patients with iodine allergy, although screening for gadolinium contraindications is still necessary.

Diagnostic Tests for Tubal Patency: Medically Recognized Screening Methods

Hysterosalpingography (HSG)

Hysterosalpingography is an X‑ray based imaging technique that evaluates the uterine cavity and fallopian tubes by introducing a radiopaque contrast medium. It is considered a first‑line screening tool for assessing tubal patency in women experiencing infertility. The test provides a visual map of any structural abnormalities, such as adhesions, septa, or extrinsic compression.

During the procedure, the patient lies in a supine position on a fluoroscopy table. A speculum is placed in the vagina, the cervix is cleansed, and a thin catheter or cannula is inserted into the uterine cavity. Contrast dye, usually iodine‑based, is slowly injected while real‑time X‑ray images are captured. The clinician observes the flow of dye through the uterus, tubes, and peritoneal cavity.

Normal findings show free spill of contrast from both tube fimbriae into the peritoneal cavity. A blockage may appear as an abrupt termination of dye within a tube (proximal or distal) or as absent spill. HSG can also reveal uterine filling defects such as polyps or fibroids. While generally safe, there is a small risk of pelvic infection or allergic reaction to the contrast agent.

X‑ray image showing contrast flowing through the fallopian tubes during a hysterosalpingography exam

Sonohysterography (Saline Infusion Sonography)

Sonohysterography, also called saline infusion sonography (SIS), uses transvaginal ultrasound combined with the instillation of sterile saline to delineate the uterine lumen and assess tubal patency indirectly. The saline expands the uterine cavity, improving visualization of endometrial pathology and facilitating observation of tubal flow when bubbles are added. It is less invasive than HSG and avoids ionizing radiation.

The examination begins with an empty bladder. A transvaginal probe is inserted, and a small catheter is passed through the cervix into the uterine cavity. Sterile saline is infused slowly while the ultrasound scanner captures real‑time images. To evaluate tubal patency, agitated saline (creating microbubbles) or a contrast agent may be injected, allowing the operator to see bubbles traversing the tubal ostia.

Interpretation focuses on the appearance of bubbles exiting the tubal ostia into the peritoneal cavity. Absence of bubble passage suggests possible tubal obstruction, whereas symmetric bilateral bubble flow indicates patency. SIS can also detect intrauterine adhesions, submucosal fibroids, or endometrial polyps. Limitations include operator dependence and difficulty visualizing distal tubal segments in some cases.

Laparoscopy with Chromopertubation

Laparoscopy combined with chromopertubation is regarded as the gold standard for direct visualization of tubal anatomy and functional patency. A minimally invasive surgical approach allows the clinician to inspect the pelvic organs, assess adhesions, endometriosis, or tubal damage, and then introduce a colored dye through the uterus to observe tubal flow.

Under general anesthesia, a small incision is made near the umbilicus for the laparoscope insertion, and additional ports are placed for manipulative instruments. The uterus is grasped, and a catheter is inserted transcervically to inject a blue or green dye (commonly methylene blue or indocyanine green) into the uterine cavity. The laparoscopic view enables real‑time observation of dye passage through the fimbriated ends of the tubes.

Patency is confirmed when dye freely exits both tubal ostia into the peritoneal cavity. A blockage is inferred if dye fails to emerge from a tube, shows delayed or asymmetric flow, or if there is visible tubal scarring, phimosis, or hydrosalpinx. Although highly accurate, the procedure carries surgical risks such as bleeding, infection, or injury to surrounding organs, and requires anesthesia and operative facility.

Laparoscopic view of dye being injected into the fallopian tubes during chromopertubation

Hysterosalpingo‑contrast Sonography (HyCoSy)

HyCoSy combines transvaginal ultrasound with an ultrasound‑visible contrast agent to evaluate tubal patency without radiation exposure. The technique leverages the echogenic properties of microbubble‑based contrast to delineate the uterine cavity and fallopian tubes in real time. It is increasingly used as an office‑based alternative to HSG.

After bladder emptying, a transvaginal probe is positioned. A thin catheter is introduced via the cervix into the uterine cavity. The ultrasound‑compatible contrast, typically a stabilized microbubble solution, is infused slowly while the operator monitors the uterine lining and tubal lumen on the screen. The echogenic bubbles enhance the visibility of fluid movement through the tubes.

A normal study demonstrates bilateral bubble transit from the uterine cornua through the tubal lumen and out into the peritoneal cavity, seen as transient echogenic streaks. Failure of bubbles to traverse a tube indicates possible obstruction. HyCoSy can also detect uterine abnormalities such as septa or submucosal myomas. Advantages include lack of ionizing radiation, reduced discomfort, and immediate results; limitations involve dependence on examiner skill and occasional difficulty visualizing distal tubal ends.

Magnetic Resonance Hysterosalpingography (MR‑HSG)

MR‑HSG employs magnetic resonance imaging to assess tubal patency using a gadolinium‑based or water‑based contrast agent introduced into the uterine cavity. This method provides high‑resolution, three‑dimensional images of the uterus, tubes, and surrounding pelvic structures without exposing the patient to ionizing radiation. It is particularly useful when detailed anatomic mapping is needed, such as prior to reconstructive surgery.

The patient is positioned supine within the MRI scanner. A catheter is placed transcervically, and a dilute contrast solution (often gadolinium‑chelated or saline with manganese) is slowly infused while sequential MRI sequences are acquired. T1‑weighted or balanced steady‑state free precession sequences capture the movement of contrast through the tubal lumen and its spill into the peritoneal cavity.

Patency is demonstrated by symmetric, free flow of contrast from both tube ostia into the peritoneal space on post‑contrast images. A blockage appears as focal signal termination within a tube or absent distal signal. MR‑HSG can concurrently identify adenomyosis, endometriotic implants, or tubal tuberculosis. Drawbacks include higher cost, limited availability, and the need for patients to remain still for extended scan times, which may be uncomfortable for some.