Diagnostic Ultrasound - Abdomen and Pelvis

Hydrosalpinx
TERMINOLOGY
Definitions
• Fluid-filled dilatation of fallopian tubes resulting from tubal
obstruction
• Must be distinguished from pyosalpinx or hematosalpinx
based on tubal content and clinical picture
• May /be isolated finding or bilateral or part of a complex
adnexal pathologic process
IMAGING
General Features
• Best diagnostic clue
○ Dilated tubular structure in adnexa separate from uterus
and ovaries containing incomplete septa, which are due
to dilated tube folding upon itself
• Location
○ Adnexal but separate from ovary
• Morphology
○ Cystic pelvic mass or complex fluid collection
○ Oval
○ Pear shaped
○ Convoluted or S-shaped, dilated tubular structure
○ More dilated at fimbriated end
○ Content anechoic or may contain low-level echoes
(debris)
Ultrasonographic Findings
• Thin-walled distended tube
○ Tube wall < 3 mm
○ Walls well defined and echogenic
○ Wall could be thicker in setting of chronic dilation (due to
fibrotic changes)
• Waist sign: Indentation of opposing walls of dilated tubal
structure, resulting in appearance of a waist
• Thin endosalpingeal folds
○ "Beads on a string" sign: Small hyperechoic mural
nodules on transverse imaging
○ ~ 2-3 mm in size
○ Form due to flattened and fibrotic tubal folds as result of
progressive (and chronic) dilation
○ Folds could also be flattened and effaced, resulting in
smooth appearance of wall
– Difficult to distinguish from other pelvic cystic masses
• Thicker endosalpingeal folds produce cogwheel sign in
acute PID
○ Cogwheels represent thickened longitudinal folds of
dilated tube
• Incomplete septa
○ Short linear echogenic projections into lumen from tubal
kinking
• Fluid in tube and cul-de-sac is anechoic
○ Debris or echoes suggest PID
• Separate and distinguishable normal ovary and uterus
○ If extensive pelvic adhesions are present, dilated tube
can be deformed and simulate other pelvic masses
• Doppler findings
○ High resistance flow in wall of hydrosalpinx
– Resistive index (RI): ≥ 0.7
– Higher resistance than acute PID
○ No flow in endosalpingeal folds
• Adnexal torsion is complication
Imaging Recommendations
• Best imaging tool
○ Transvaginal ultrasound
• Protocol advice
○ Look for intact separate ovary
○ Use high gain settings to look for echoes in fluid
○ Cine clips can be very helpful to confirm tortuous folded
tube
○ 3D-rendered US can help see tortuous structure, which is
difficult to follow with 2D imaging
• Inconclusive findings can be better assessed with MR
• Hysterosalpingogram (HSG) is mainstay of tubal patency
evaluation
MR Findings
• If ultrasound findings are atypical, incompletely evaluated
or another associated adnexal mass is seen, proceed to MR
○ T1WI
– Tubular dilated structure separate from ovaries and
uterus
– Tube content has low SI if simple fluid
– Proteinaceous or hemorrhagic fluid is intermediate to
high signal intensity depending on content of tube
– High SI is correlated to pelvic and tubal endometriosis
○ T2WI
– Tube content is high SI
– Incomplete septa are of low SI
– T2* helpful in identifying hemorrhagic content
– Heavily T2 FSE (long effective echo time of 250-350
msec) result in significantly hyperintense simple fluid,
while layering debris or clot will appear low SI within
fluid content
○ T1WI with contrast material
– Mild enhancement of tubal wall and septa, which
could also be thickened
– Significant enhancement suggestive of active
inflammatory process
• MR hysterosalpingography has been reported in literature
○ Diluted contrast agent instilled into uterine cavity via a
cannula followed by multiplanar imaging
Fluoroscopic Findings
• HSG
• Dilated fallopian tube without spillage of contrast material
into peritoneal cavity from fimbriated end
• Can be bilateral
DIFFERENTIAL DIAGNOSIS
Pyosalpinx (Acute PID)
• Tube distended with echogenic material
• Tube wall > 5 mm and thick endosalpingeal folds
○ Hypervascular on Doppler imaging
• Low resistive flow in walls and folds (RI ≤ 0.5)
• Patient is symptomatic with tenderness during transvaginal
exam
• May be accompanied with adnexal inflammatory changes,
ovarian enlargement, endometritis, and parovarian fluid
collections
Diagnoses: Female Pelvis
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