Introduction

Hysterosalpingography (HSG) is the radiographic evaluation of the uterus and fallopian tubes and is used predominantly in the evaluation of infertility.

The primary role of HSG is in the evaluation of the fallopian tubes.

Ultrasonography (US) is currently used for evaluation of the endometrium (ie, abnormal uterine bleeding, polyps) and pregnancy, whereas magnetic resonance (MR) imaging is used more in the evaluation of the uterine myometrium (ie, uterine contour, myomas) and the ovaries.

Indications for HSG

Contraindications :

1. Pregnancy
2. Active pelvic infection
3. Recent dilatation and curettage or abortion or immediately post-menstruation. This apply only to oily contrast medium because of the risk of intravasation. ( Oily contrast medium is no longer recommended ).

Contrast medium :

HOCM or LOCM 300. Volume 10-20ml.

LOCM have no advantage with regard to image quality or side effects but the non-ionic dimer, iotrolan, is associated with a lower incidence

and decreased severity of delayed pain.

Patient prep:

1. The patient should abstain from intercourse between booking the appointment and the time of the examination unless she uses a reliable method of

contraception. OR

The examination can be booked between the 4th and 10th days in a patient with regular 28-day cycle.

2.Apprehensive patients may need premedication.

3.Because patients may experience cramping during the examination, women are advised to take a nonsteroidal anti-inflammatory drug 1 hour prior to the procedure.

Prelim film :

coned PA view of the pelvic cavity.

Technique :

1. The patient is placed supine on the fluoroscopy table in the lithotomy or modified lithotomy position.( The patient lies supine on the table with knees flexed, legs abducted and heels together.)

2. Using aseptic technique the operator inserts a speculum and cleans the vagina and cervix with chlorhexidine.

3. The anterior lip of the cervix is steadied with the vulsellum forceps and the  cannula is inserted into the cervical canal. If a Foley catheter is used, there is usually no need to grasp the cervix with the vulsellum forceps.

4. Care must be taken to expel all air bubbles from the syringe and the cannula.

5. Place a metallic marker over one side of the pelvis to indicate the right or left side of the patient.

Films:

1. A scout radiograph of the pelvis is obtained with the catheter in place before contrast material is instilled.The first image (Pic F1) is obtained during early filling of the uterus and is used to evaluate for any filling defect or contour abnormality. Small filling defects are best seen at this stage.
2. The second image (Pic F2) is obtained with the uterus fully distended. The shape of the uterus is best evaluated at this stage, although small filling defects may be obscured when the uterus is well opacified.
3. The third image (Pic F3) is obtained to demonstrate and evaluate the fallopian tubes.
4. The fourth image (Pic F4) should exhibit free intraperitoneal spillage of contrast material.
5. Oblique views of the fallopian tubes may be obtained as needed to “elongate” the tubes or displace superimposed structures.

Complications of HSG

A)    Due to contrast medium : 1) Allergic phenomenon

B)    Due to the technique :

1) Pain at the following times :

1. Using the vulsellum forceps.
2. During insertion of the cannula.
3. With tubal distension proximal to a block.
4. With distension of the uterus if there is tubal spasm.
5. With peritoneal irritation during the following day up to 2 weeks.

2) Bleeding from trauma to the uterus or cervix.

3) Transient nausea, vomiting and headache.

4) Intravasation of contrast medium into the venous system of the uterus results in a fine

lace-like pattern within the uterine wall. When more extensive, intravasation outline

larger veins. The following factors predispose to intravasation :

a)      direct trauma to the endometrium.

b)      Timing of the procedure near to menses.

c)      Timing of the procedure within few days after curettage.

d)     Tubal occlusion because of the high pressure generated within the uterine cavity.

e)      Uterine abnormalities : uterine TB, carcinoma adn fibroids.

5) Infection.

6) Abortion.

Uterus

The uterus is a muscular sac that houses the fetus during gestation. The size of the uterus varies depending on the patient’s age and parity. HSG is helpful in the evaluation of the uterine cavity only, providing indirect information about the remainder of the uterus. The uterine cavity is triangular, with the base directed cranially and the apex caudally. The cervix constitutes the most inferior aspect of the uterus and extends into the vagina. The isthmus is the uterine portion immediately above the cervix. The majority of the uterus is composed of the body, or corpus. The uppermost aspect of the uterus is the fundus, which can be concave, flattened, or slightly convex. The fallopian tubes connect to the fundus at the cornua, or lateral extremes of the base of the triangular cavity.

At HSG, the uterus should look like an inverted triangle with well-defined, smooth contours. Uterine anomalies can be due to:

(a) congenital abnormalities of uterine shape,

(b) luminal filling defects, or

(c) abnormalities of uterine contour.

Congenital Abnormalities of Uterine Shape

Congenital abnormalities of uterine shape are due to abnormal fusion of the müllerian ducts during early (6–12 weeks) gestation. A unicornuate uterus results if one of the müllerian ducts does not form properly. If the two müllerian ducts do not completely fuse, a bicornuate uterus is formed. All bicornuate uteri will demonstrate a cleft in the outer contour of the fundus. The amount of fusion of the müllerian ducts can vary from minimal union to nearly complete union. When the two ducts fuse but there is incomplete resorption of the intervening septum, a septate uterus results. The length of the septum can vary depending on the degree of resorption (complete vs partial septum), similar to the bicornuate uterine anomaly. An arcuate uterus is considered by some to be a mild form of septate uterus in which there is mild concavity of the uterine cavity in the fundus. Unlike the bicornuate uterine deformity, the septate and arcuate deformities have a normal outer uterine contour. Optimal visualization of the outer contour is important in differentiating among these various anomalies. Thus, MR imaging has become the preferred imaging modality rather than HSG. In recent years, the introduction of three-dimensional US has allowed visualization of the outer uterine contour with this modality as well. Three-dimensional transvaginal US promises to play an important role in contour evaluation. Because the genital and urinary systems develop embryologically from a common ridge of mesoderm, congenital abnormalities of the uterus are often accompanied by renal abnormalities.

Figure 2. Unicornuate uterus. Spot radiograph demonstrates a single uterine horn with an irregular medial contour. A single fallopian tube is also visualized.

Figure 3. Bicornuate uterus. Spot radiograph shows two markedly splayed uterine horns. The fallopian tubes are not visualized at this imaging stage.

Figure 4. Septate and arcuate uterus. Spot radiograph demonstrates a depression of the uterine fundus, a finding that may represent a short septum or an arcuate deformity.

Luminal Filling Defects

Filling defects are common findings at HSG. Care should be taken to flush the catheter thoroughly with contrast material to avoid injecting air bubbles. Air bubbles manifest as well-circumscribed lucencies that collect in the nondependent portion of the uterus. They are often mobile or transient when they are expelled into the fallopian tubes. This fact can help differentiate air bubbles from fixed filling defects. Despite the best efforts, air bubbles are occasionally seen.

Figure 5a. Air bubbles. Spot radiograph shows air bubbles (arrow) in the left side of the uterus.

Figure 5b.Spot radiograph no longer depicts the air bubbles seen in the left cornua of the uterus.

Uterine folds are normal variants that are occasionally seen at HSG. They are believed to be caused by infolding of the inner aspect of the myometrium in an underdistended uterus. Uterine folds parallel the long axis of the uterus and can extend into the uterine horns.

Figure 6. Uterine folds. HSG spot radiograph demonstrates uterine folds (arrows) as linear filling defects that parallel the longitudinal axis of the uterus. Uterine folds are normal findings that are occasionally seen at HSG.

Synechiae are intrauterine adhesions that result from scarring, most commonly secondary to the endometrial trauma of curettage. Endometrial infections may also result in synechia formation. Synechiae manifest as irregular filling defects, most commonly as linear filling defects arising from one of the uterine walls. Multiple synechiae associated with infertility is known as Asherman syndrome.

Figure 7a. Synechiae.  Spot radiograph shows a central oval filling defect within the uterus, a finding that represents a synechia.

Figure 7b.Spot radiograph obtained in a different patient demonstrates a short linear defect (arrow) along the inferior left side near the uterine isthmus.

Abnormalities of Uterine Contour

Leiomyomas are benign tumors of the smooth muscle of the uterus. They may be in subserosal, intramural, or submucosal locations within the uterine wall. Leiomyomas manifest as well-defined filling defects at HSG and can have a variety of appearances depending on their size and their location within the uterus. Only submucosal myomas are depicted at HSG. Small myomas, like polyps, can best be seen during early contrast material filling of the uterus but may be obscured when the uterus is completely opacified. Large myomas can distort the size and shape of the uterine cavity.

Figure 9a. Leiomyomas. Spot radiograph obtained during the early filling stage shows a well-defined filling defect (arrow) in the fundus.

Figure 9b. Leiomyomas. On a spot radiograph obtained with the uterus more distended with contrast material, the fibroid (arrow) is less apparent.

Figure 9c. Leiomyomas.  Spot radiograph obtained in a different patient reveals a large leiomyoma distorting the endometrial cavity as it drapes over a mass in the left myometrium.

Adenomyosis is a condition in which endometrium extends into the myometrium. Adenomyosis can be diffuse or focal in the uterus. A focal area with a mass-like configuration has been termed an adenomyoma. Adenomyosis may be imaged with HSG if nests of endometrial tissue connect to the uterine cavity. At HSG, adenomyosis appears as small diverticula extending into the myometrium. Because adenomyosis generally manifests as pelvic pain or abnormal bleeding, it is more commonly detected with MR imaging or US and is an incidental finding at HSG performed in an infertile woman. At MR imaging, adenomyosis appears as thickening of the junctional zone to 1 cm or more. At US, it manifests as diffuse or focal areas of heterogeneous myometrial echotexture. MR imaging is the optimal imaging modality when adenomyosis is a clinical consideration.

Figure 10a. Diffuse adenomyosis.  Spot radiograph shows irregularity of the uterine contour with small outpouchings of contrast material, findings that represent diffuse adenomyosis.

Many women who present for HSG report a history of uterine surgery. For example, a history of cesarean section is common in younger women. Women who have undergone myomectomy for a submucosal fibroid can have irregularity of the uterine contour in the myomectomy bed or, rarely, can develop a small diverticulum at the site.

Figure 11. Cesarean section scar. Spot radiograph shows the uterine incision from a cesarean section (arrows) in the typical location (ie, oriented transverse in the lower uterine segment in the region of the isthmus). At HSG, a cesarean section scar can have a linear appearance (as in this case) or can occasionally manifest as a wedge-shaped outpouching or diverticulum.

Fallopian Tubes

The fallopian tubes serve as the passageway for the ovum to travel from the ovary to the uterus. They are 10–12 cm in length and course along the superior aspect of the broad ligament. Each fallopian tube can be divided into three segments radiographically. The interstitial or cornual region is the short segment that traverses the muscular wall of the uterus. The isthmic portion is the longest of the three segments and is the narrow segment between the interstitial and ampullary regions. The ampullary portion is the widened region near the ovary. The fimbriated part is the funnel-shaped end of the tube and is not usually seen at HSG.

HSG is the best method for visualizing and evaluating the fallopian tubes. Contrast material–enhanced sonohysterography has been suggested as a means of assessing tubal patency. A contrast agent is instilled into the uterus through an HSG catheter and is imaged as it exits the patent tube. However, US contrast agents are not approved by the U.S. Food and Drug Administration and are not widely used in the United States. In addition, contrast-enhanced sonohysterography does not allow visualization of the entire tube. MR hysterography with a heavily T2-weighted sequence (a procedure that is similar to MR cholangiopancreatography) has also been suggested for visualization of the fallopian tubes. However, the size of the normal fallopian tube is at or below the resolution of most MR imagers. Moreover, even if the tube is visualized, MR hysterography does not help assess tubal patency. Instillation of saline solution or water through an HSG catheter in conjunction with MR hysterography is possible, but this procedure has not gained wide acceptance.

At HSG, the fallopian tubes should appear as thin, smooth lines that widen in the ampullary portion. The isthmic portion has been likened to a piece of spaghetti in appearance. The fallopian tubes vary in location within the pelvis and in degree of tortuosity. There should be free spillage of contrast material into the peritoneal cavity. Tubal abnormalities seen at HSG can be either congenital or due to spasm, occlusion, or infection.

Salpingitis isthmica nodosum (SIN) is of unknown cause. It is associated with infertility, PID, and, occasionally, ectopic pregnancy. SIN appears as small outpouchings or diverticula from the isthmic portion of the fallopian tube and can affect one or both tubes.

Figure 12. SIN. Spot radiograph demonstrates SIN as small outpouchings or diverticula from the isthmic portion of the fallopian tubes. SIN can be either unilateral or (as in this case) bilateral.

The cornual portion of the fallopian tube is encased by the smooth muscle of the uterus. If there is spasm of the muscle during HSG, one or both tubes may not fill beyond the interstitial portion.At radiography, tubal spasm cannot be distinguished from tubal occlusion. Administration of a spasmolytic agent such as glucagon can occasionally result in uterine muscle relaxation and consequent tube opacification,hereby helping differentiate cornual spasm from true occlusion.

Figure 13a. Cornual spasm. On an HSG spot radiograph obtained during the early filling stage of the uterus, the right fallopian tube does not opacify beyond the cornual portion (arrow), whereas the left fallopian tube opacifies to the ampullary portion. Arrowheads indicate amorphous calcifications on the right side of the pelvis. These calcifications were also present on the scout image (not shown).

Figure 13b. On a spot radiograph obtained after the instillation of additional contrast material, the right fallopian tube opacifies to the ampullary portion. Right-sided SIN and a left-sided hydrosalpinx are also noted. Amorphous calcifications (arrowheads) are again seen on the right side of the pelvis.

PID is the most common cause of tubal occlusion leading to infertility. Although active pelvic infection is a contraindication for HSG, the residua of previous episodes can be seen at HSG. Tubal occlusion manifests as an abrupt cutoff of contrast material with nonopacification of the more distal fallopian tube, can be unilateral or bilateral, and can affect any portion of the tube. If the blockage is in the ampullary portion, the tube may dilate, forming a hydrosalpinx. Another sequela of PID is scarring in the peritoneal cavity surrounding the fallopian tube. Peritubal adhesions prevent contrast material from flowing freely around the bowel loops and most commonly manifest as loculation of the contrast material around the ampullary portion of the tube.

Figure 14(b) Spot radiograph demonstrates cutoff of contrast material in the isthmic portions of both fallopian tubes, with bulbous dilatation of the distal aspects of the opacified portions. These findings can be seen with postsurgical occlusion (eg, following tubal ligation).

Figure 15a. Hydrosalpinx.  Steep right oblique spot radiograph shows dilatation of the ampullary portion of the right fallopian tube (arrow). The left fallopian tube is normal in caliber. Mucosal folds are visible in the ampullary portions of both fallopian tubes, a finding that helps confirm the presence of contrast material within the tubes.

Figure 16. Peritubal adhesions. Spot radiograph demonstrates a round collection of contrast material adjacent to the left fallopian tube, a finding that suggests peritubal adhesions. Note the free contrast material spillage on the right side.

Occasionally, HSG is performed for postoperative evaluation of the fallopian tubes—for example, documentation of tubal occlusion following tubal ligation. Such occlusion appears as an abrupt termination of the tube at the surgical site or mild bulbous expansion of the tube with cutoff. HSG may also be performed to demonstrate tubal patency without extravasation of contrast material after reversal of a ligation procedure. A new irreversible occlusion device called Essure (Conceptus, San Carlos, Calif), was recently introduced. This soft, flexible microinsert is placed hysteroscopically into each fallopian tube, thereby obviating laparoscopy. The micro-insert induces scar tissue formation around itself after a few months. At that time, HSG is usually performed to evaluate for tubal occlusion.

Figure 17a. Irreversible tubal occlusion with a microinsert.  Scout radiograph obtained prior to the instillation of contrast material shows a microinsert that has been placed hysteroscopically into the proximal fallopian tube.

Figure 17b. Irreversible tubal occlusion with a microinsert. Radiograph obtained after instillation shows no contrast material filling of the fallopian tube beyond the microinsert, a finding that helps document tubal occlusion.

Tubal polyps are rare. They represent ectopic endometrial tissue located in the interstitial portion of the tube. Tubal polyps manifest as smooth, rounded filling defects in this location, without concomitant dilatation or tubal occlusion. These polyps are less than 1 cm in diameter and can be either unilateral or bilateral. Women with tubal polyps are asymptomatic, and the association of these polyps with infertility has not been established.

Figure 18. Tubal polyp. Spot radiograph shows a small filling defect (arrow) in the proximal left fallopian tube, a finding that typically represents a tubal polyp.

Conclusions

HSG is a valuable tool in the evaluation of the uterus and fallopian tubes. Radiologists should become familiar with HSG technique, the interpretation of HSG images, and possible complications of this procedure.

Reference:

1.      Hysterosalpingography: A Reemerging Study

http://radiographics.rsna.org/content/26/2/419.short

2.  A Guide to Radiological Procedures by Stephen Chapman.

3. The American Congress of Obstetricians and Gynaecologists.