Diagnostic Ultrasound - Abdomen and Pelvis

Uterine Anomalies
TERMINOLOGY
Abbreviations
• Müllerian duct anomalies (MDA)
Synonyms
• Uterine fusion anomalies
Definitions
• MDA: Series of uterine malformations resulting from
abnormal development, fusion, or resorption of müllerian
ducts
○ Unicornuate, bicornuate, didelphys uterus ±
cervical/vaginal malformation
IMAGING
General Features
• Best diagnostic clue
○ Abnormal configuration of endometrial cavity ±
abnormal external contour of uterus
Ultrasonographic Findings
• Grayscale ultrasound
○ Arcuate uterus
– Most common MDA
– Minimal indentation of fundal endometrium
– Normal external uterine contour
○ Septate uterus
– 2nd most common MDA
– 2 endometrial cavities, septum of variable length and
thickness
□ Thin fibrous septum variably present
– May be difficult to discern outer uterine contour:
Imaging overlap with bicornuate uterus
□ Convex outer uterine contour or cleft < 1 cm
□ Intercornual angle < 75° suggests septate uterus
○ Bicornuate uterus
– 3rd most common MDA
– 2 symmetric uterine horns, fused inferiorly
– May be difficult to discern outer uterine contour:
Imaging overlap with septate uterus
□ Deep fundal cleft > 1 cm
□ Intercornual angle > 105° suggests bicornuate
uterus
□ Intercornual distance > 4 cm favors bicornuate
uterus
– May have single cervix (unicollis) or duplication
(bicollis)
○ Unicornuate uterus
– Curved and elongated banana-shaped single uterine
horn and endometrium
– Hypoplastic contralateral horn often present
□ Hematometros (HM) when obstructed
□ May or may not communicate with unicornuate
horn
○ Uterus didelphys
– 2 separate noncommunicating divergent uterine
horns
– Deep fundal cleft
– 2 cervices
– Vaginal septum in 75%
□ Hematometrocolpos (HC) if obstructed
○ Müllerian agenesis or hypoplasia
– Absent or small rudimentary uterus
– ± hematometros
○ DES uterus (T shaped)
– Nonspecific appearance on 2D US
• 3D
○ Vital for correct diagnosis of MDA
– True coronal plane allows for better sonographic
evaluation of uterine fundal contour
MR Findings
• Appearance dependent upon MDA type
• T2WI: Best for visualizing outer uterine contour, zonal
anatomy
• T1WI: High signal endometrium indicates hematometros
when obstructed
CT Findings
• MPR images can demonstrate outer uterine contour and
endometrial cavity but not study of choice
Fluoroscopic Findings
• Hysterosalpingography: Variable appearance of uterine
cavity/cavities depending upon MDA type
○ Limited as outer uterine contour not visible
Imaging Recommendations
• Best imaging tool
○ Ultrasound as initial imaging test
○ MR to clarify anatomy, relationship of pelvic organs
– Better than ultrasound in defining uterine contour,
identifying rudimentary uterine horns
• Protocol advice
○ Ultrasound
– 3D essential to evaluate uterine fundal contour
– Limited until puberty, secondary to small uterine size
○ MR
– T1 and T2WI to evaluate anatomy, blood products
□ True coronal images of uterus to evaluate fundal
contour
– Include renal fossae on coronal views
DIFFERENTIAL DIAGNOSIS
Imperforate Hymen
• Uterus/vagina distended with mucous secretions or blood
• Not associated with MDA
• Need to differentiate from low transverse vaginal septum
Cervical Stenosis
• Can cause obstruction and distortion of endometrial cavity,
mimicking MDA
Pyometra
• Associated with fever, elevated white cell count
• Clinical diagnosis as complex fluid on imaging, may be pus
or blood
PATHOLOGY
General Features
• Etiology
Diagnoses: Female Pelvis
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