What are the indications for hysteroscopy (hysteroscopic procedure) versus transvaginal ultrasound (TVUS)?

Indications for Hysteroscopy vs. Transvaginal Ultrasound

Hysteroscopy is the gold standard for evaluating intrauterine pathology and should be used as the primary diagnostic tool for direct visualization of the uterine cavity when intrauterine abnormalities are suspected, while transvaginal ultrasound (TVUS) serves as an excellent initial screening tool for evaluating pelvic structures. 1

Hysteroscopy Indications

Hysteroscopy allows direct visualization of the uterine cavity and is superior for:

• Diagnosis and treatment of intrauterine pathologies that project into the uterine cavity, including endometrial polyps, submucous myomas, endometrial hyperplasia, and endometrial adenocarcinoma 2, 1
• Evaluation of abnormal uterine bleeding, particularly when initial TVUS shows abnormalities 3
• Infertility evaluation requiring direct visualization of the uterine cavity 4
• Targeted biopsy of suspicious lesions 1
• Therapeutic interventions including removal of endometrial polyps, treatment of submucous fibroids, correction of uterine septa, and lysis of intrauterine adhesions 1
• Definitive diagnosis of intrauterine adhesions (Asherman syndrome), with significantly higher sensitivity than conventional TVUS 5
• Assessment of complex intrauterine abnormalities when other imaging modalities are inconclusive 2

Advantages of Hysteroscopy

• Provides direct visualization with high diagnostic accuracy 1
• Allows for simultaneous diagnosis and treatment (see-and-treat approach) 1
• Can be performed in ambulatory settings with high patient acceptability 1
• Serves as the gold standard for evaluating intrauterine pathology 3, 1
• Superior sensitivity for detecting small endometrial polyps compared to TVUS 3

Transvaginal Ultrasound (TVUS) Indications

TVUS is appropriate as an initial screening tool for:

• Initial evaluation of female infertility, particularly for assessing ovulatory function and ovarian reserve 5
• Screening for uterine abnormalities before proceeding to more invasive procedures 4
• Evaluation of patients with clinical features or history of polycystic ovary syndrome (PCOS) 5
• Assessment of endometrial thickness and morphology 5
• Detection of larger submucous fibroids (sensitivity of 91% and specificity of 100% compared to hysteroscopy) 5
• Initial evaluation of adenomyosis, particularly when combined with color Doppler 5
• Routine gynecological examinations 3

Advantages of TVUS

• Non-invasive and well-tolerated 3
• Provides good initial assessment of both uterine cavity and surrounding structures 5
• High negative predictive value (86%) for ruling out intrauterine pathology 6
• Can be performed easily in outpatient settings 3
• Allows evaluation of extrauterine pelvic structures not visible with hysteroscopy 5

Comparative Diagnostic Accuracy

• For detecting submucous fibroids:

  • TVUS has 91% sensitivity and 100% specificity compared to hysteroscopy 5
  • Hysteroscopy and sonohysterography (SIS) are superior to conventional TVUS 5

• For detecting intrauterine adhesions:

  • Conventional TVUS shows only 52% sensitivity compared to hysteroscopy 5
  • 3D-TVUS demonstrates improved sensitivity (100%) for grading intrauterine adhesions 5

• For detecting endometrial polyps:

  • Hysteroscopy has significantly better sensitivity than TVUS (p<0.001) 3
  • 3D-TVUS shows 61.1% sensitivity and 91.5% specificity for polyp detection 6

• For overall uterine cavity abnormalities:

  • 3D-TVUS demonstrates 84.1% diagnostic accuracy, 68.2% sensitivity, and 91.5% specificity compared to hysteroscopy 6

Clinical Decision Algorithm

1. Initial evaluation: Start with TVUS for screening of uterine and pelvic structures 5

2. When to proceed to hysteroscopy:

   • Abnormal findings on TVUS suggesting intrauterine pathology 3
   • Persistent abnormal uterine bleeding despite normal TVUS 1
   • Infertility evaluation requiring detailed assessment of the uterine cavity 4
   • Need for therapeutic intervention for intrauterine pathology 1
   • Suspected intrauterine adhesions (Asherman syndrome) 5

3. Consider enhanced ultrasound techniques when available:

   • Sonohysterography (SIS) for better visualization of the uterine cavity 5
   • 3D-TVUS for improved detection of congenital anomalies and intrauterine lesions 5, 6

Common Pitfalls and Caveats

• Conventional TVUS has limited sensitivity (52%) for detecting intrauterine adhesions; proceed to hysteroscopy when adhesions are suspected 5
• Small endometrial polyps (<1cm) may be missed on TVUS; hysteroscopy has superior detection rates 3
• TVUS cannot replace hysteroscopy for definitive diagnosis of intrauterine pathology, particularly for small lesions 3, 1
• Hysteroscopy is limited in evaluating the myometrium and extrauterine structures, where TVUS or other imaging modalities are superior 2
• For comprehensive infertility evaluation, a combination of imaging modalities may be necessary to assess both the uterine cavity and tubal patency 5