GU Studies
Hysterosalpingography (HSG)
Anatomy
Students should be able to identify the following structures on radiographic images:
Uterus (fundus, body, cervix, and uterine cavity), Fallopian (uterine) tubes, fimbriae, Ovaries, Peritoneal cavity.
Indications, Contraindications, and Patient Preparation
Indications
- Infertility evaluation (assessment of fallopian tube patency).
- Evaluation of uterine abnormalities (polyps, fibroids, adhesions, congenital anomalies).
- Investigation of recurrent miscarriage.
- Post-surgical assessment (tubal ligation reversal, uterine reconstruction).
- Assessment of intrauterine device (IUD) placement.
Contraindications
- Pregnancy.
- Active pelvic infection.
- Recent uterine or tubal surgery (risk of perforation).
- Severe contrast sensitivity.
Patient Preparation
- Exam scheduled 7–12 days after the onset of menstruation (endometrium least congested, avoids early pregnancy).
- Patient should empty bladder before exam.
- Cleansing enemas may be given if bowel preparation is needed.
- Vaginal irrigation and perineal cleansing immediately prior.
- Outpatient exam; patient may rest briefly after procedure due to cramping.
Procedure Overview
Hysterosalpingography (HSG) is a fluoroscopic procedure that evaluates the uterine cavity and fallopian tube patency using direct instillation of iodinated contrast through a uterine cannula.
The exam is typically performed 7–12 days after the onset of menstruation, when the endometrium is thin and pregnancy is unlikely.
The patient is positioned in lithotomy, the cervix is cleansed, and a uterine cannula (acorn-tip or balloon type) is inserted under aseptic technique.
Contrast is injected slowly under fluoroscopic observation or intermittent overhead imaging to visualize uterine filling, tubal opacification, and contrast spill into the peritoneal cavity (confirming tubal patency).
The patient may experience transient cramping due to uterine distention. Warm contrast and gentle communication improve comfort.
- Fluoroscopy time is minimized, and exposures are taken on end-expiration to reduce motion.
- Contrast Medium: Water-soluble iodinated contrast (low viscosity; absorbed if spilled intraperitoneally).
- Equipment: Fluoroscopy unit with spot or digital capture; sterile speculum, cannula, and syringes.
- Radiation Protection: Tight collimation to pelvis; ALARA principles; shield when it does not obscure anatomy.
- Team Coordination: Performed jointly by radiologist and radiologic technologist with nursing or support staff assistance.
Routine Projections (ARRT Required)
AP Pelvis (Primary Projection)
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine in lithotomy position with knees flexed and supported in leg holders
- Adjustments: MSP centered to IR; pelvis stabilized and level; bladder emptied prior to imaging
- CR: Perpendicular to IR, centered 2 inches above the pubic symphysis
- Patient instructions: Suspend respiration and remain motionless during contrast injection and exposure
- Exposure: Routine pelvic technique; collimate to include uterus, tubes, and upper pelvic cavity
Evaluation Criteria
- Coverage (what anatomy must be included and how you verify it’s complete): Entire uterine cavity, fallopian tubes, and contrast spill into peritoneal cavity if present
- Rotation checks (how symmetry or alignment tells you if positioning is correct): Iliac wings symmetrical; spine aligned in midline
- Motion checks (how sharpness confirms patient cooperation/exposure timing): Sharp uterine and tubal outlines without motion blur
- Technique checks (what contrast, density, soft tissue visibility, and artifacts to look for): Adequate penetration to visualize contrast-filled lumina and soft-tissue margins
- Clinical aim (when applicable, e.g., reflux, obstruction, displacement, etc.): Demonstrate uterine contour, tubal patency, and presence or absence of peritoneal spill
Oblique Pelvis (RPO / LPO as Indicated)
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine, rotated 30–45° RPO or LPO
- Adjustments: Elevate and abduct upper thigh to avoid obscuring pelvis
- CR: Perpendicular, centered 2 inches above pubic symphysis and 2 inches medial to elevated ASIS
- Patient instructions: Suspend respiration; hold still during exposure
- Exposure: Same technical factors as AP; collimation adjusted to region of interest
Evaluation Criteria
- Coverage: Uterine cavity and both tubes free from bony overlap; peritoneal spill visualized when present
- Rotation checks: Appropriate obliquity evident by reduced overlap of pelvis and uterus
- Motion checks: Clear, sharply defined outlines of tubes and uterus
- Technique checks: Uniform contrast brightness; no saturation or underexposure
- Clinical aim: Clarify uterine shape and tubal course; reduce superimposition of pelvic structures
Supplemental Projections
Lateral Pelvis
CR Location & Positioning
- SID: 40 inches
- Patient position: Lateral recumbent, knees flexed slightly, arms forward
- Adjustments: Midcoronal plane centered to IR; pelvis true lateral
- CR: Perpendicular to IR, centered 2 inches above pubic symphysis at MCP
- Patient instructions: Suspend respiration and remain still
- Exposure: Low to medium mAs; short exposure time to prevent motion
Evaluation Criteria
- Coverage: Uterus and fallopian tubes in lateral profile; contrast outlines uterine cavity
- Rotation checks: Femoral heads superimposed; iliac crests aligned
- Motion checks: Sharp uterine and pelvic soft-tissue margins
- Technique checks: Adequate contrast definition without overexposure
- Clinical aim: Assess uterine orientation, wall anomalies, or fistulae; evaluate relationship to bladder and rectum
IUD Imaging
CR Location & Positioning
- SID: 40 inches
- Patient position: Supine (AP) or as indicated for lateral/oblique views
- Adjustments: Center pelvis to IR; ensure bladder and uterus within field
- CR: Perpendicular to IR at level of ASIS (pelvic midline)
- Patient instructions: Suspend respiration; remain still
- Exposure: Routine abdomen/pelvis technique; collimate to uterus
Evaluation Criteria
- Coverage: Entire uterus and IUD visualized in situ
- Rotation checks: Iliac wings symmetrical; spine midline
- Motion checks: Device edges sharply defined; no blur
- Technique checks: Radiopaque IUD clearly seen relative to uterine cavity margins
- Clinical aim: Confirm intrauterine placement and detect possible displacement or perforation
Hows & Whys of Hysterosalpingography
Anatomy
- How does contrast demonstrate tubal patency?
Contrast travels from the uterine cavity through the fallopian tubes and freely spills into the peritoneal cavity when the tubes are open. - How are uterine anomalies identified?
Abnormal contrast outlines (septate, bicornuate, or T-shaped cavities) reveal structural variations of the uterine body.
Positioning
- Why is HSG scheduled shortly after menstruation?
To avoid imaging during early pregnancy and to minimize endometrial congestion, improving visualization of the uterine cavity. - Why is the lithotomy position used?
It allows direct access to the cervix for cannula placement and provides an unobstructed AP view of the uterus and tubes. - Why use oblique projections?
They separate overlapping pelvic structures and better demonstrate the course of the fallopian tubes and uterine anomalies. - Why is respiration suspended during imaging?
To minimize motion blur and maintain consistent contrast distribution during short exposures.
Technique & Image Evaluation
- How do you confirm adequate uterine filling?
The contrast outlines the entire uterine cavity evenly without leakage or overdistention, and the patient reports only mild cramping. - How do you confirm tubal patency?
Contrast progresses smoothly through the tubes with visible peritoneal spill on late images. - How do you identify a tubal blockage?
The contrast column terminates abruptly or fails to exit the uterine cornu without free peritoneal spill. - How can you differentiate a true filling defect from a bubble artifact?
True defects persist across multiple projections, whereas air bubbles shift position or disappear with additional contrast.
Clinical Applications
- Why is water-soluble contrast preferred for HSG?
It is absorbed quickly if extravasated into the peritoneal cavity, reducing the risk of chemical peritonitis. - Why might a patient experience cramping during the exam?
Uterine contraction occurs as a physiologic response to distention and contrast injection. - Why is peritoneal spill important?
It confirms tubal patency, the key diagnostic outcome in infertility evaluations. - Why is patient reassurance essential during the procedure?
Anxiety and discomfort can increase uterine spasm, leading to false impressions of obstruction or incomplete filling.