FEMALE GENITAL TRACT RADIOLOGY
Dr. Khaleel Ibraheem
US
is the principle imaging modality :
1-TAS: full bladder, difficult in obese, surgical scar, acute abdomen
2-TVS: empty bladder, better resolution
Uterus is pear shaped structure ,lying posterior to the UB , continuous
down ward with the vagina with the characteristic mid line echo from
apposition of the two vaginal walls
The endometrium is clearly identified by its echogenic appearance
.It varies according to the phase of the cycle (triple line in mid cycle).
The ovaries are seen on either side of the uterus , characterized by
the presence of multiple anechoic small follicles , the dominant follicle
starts to ripe at Day8 till mid cycle (Day 14) , ruptured follicle appears
small as it form CL & free pelvic fluid at the cul de sac is seen
Ovarian size varies according to the age of the Pt.(2.5-5cm).The
normal fallopian tubes can not be identified on US
CT:
cross sectional anatomy of the pelvis, can not demonstrate the
normal ovaries. Need oral & i.v. contrast
MRI:
excellent soft tissue contrast in sagittal & axial T2 WI sections.
Coronal sections used for the ovaries
Radiology :
limited , HSG
Pelvic masses:
US :determine cystic from solid masses (cystic ?benign , Solid
?malignant )
A limitation of imaging is that it is sometimes not possible to
determine from which organ the mass arises.
Cross sectional studies are particularly required in ?malignant masses
FEMALE GENITAL TRACT RADIOLOGY 17
OVARIAN CYSTS
Persistence of follicle or CL in first trimester results
in follicular cyst
US: thin walled , unilocular , anechoic , no solid portion
CT : fluid density (0-10HU)
MRI: low intensity T1, high intensity T2.
Ovarian tumours:
Cyst adenoma/CA are the commonest
Can be cystic or solid or mixed, the cystic tumors can be multilocular.
Imaging can determine the size, consistency & location of ovarian mass.
Imaging cannot determine the nature of mass.
Features indicating malignancy:
1.
Thick septa
2.
Multiloculation
3.
Solid nodule
4.
Invasion of the surrounding organs (bladder, rectum , bowel )
5.
Ascites
6.
LAP
7.
Omental & peritoneal metastases are difficult to detect
8.
Liver metastases
Imaging may show hydronephrosis from ureteric obstruction by
tumors, may demonstrate LAP & liver metastases.
Dermoid cyst:
Plain film : calcification /soft tissue shadow
US: layering of high level echoes with fluid (fat/fluid level)
CT :mixed component (fat/-100 HU, fluid , calcification)
MRI: high SI T1, intermediate SI T2, signal void areas (calcification),
suppression of signal in fat suppression seq.
Uterine Masses:
► Fibroids
: single or multiple, subserous, submucous , intramural
Plain film: soft tissue shadow , pop corn calcification
US : lobulated or rounded mass of variable echo texture +/- calcification
CT: soft tissue mass similar density as myometrium.
MRI :low SI T1, variable SI T2
► CA cervix
:
Cross sectional study plays vital role in staging of the tumor rather than
to make the initial diagnosis as staging would affect the mode of
treatment
1. The extent of tumor within & outside the cervical canal into
parametrium, rectum, bladder, pelvic side walls
2. Pelvic LAP
3. Ureteric obstruction
CT is less accurate than MRI for local staging.
►
CA endometrium:
Cross sectional study plays limited role, MRI can predict the depth of
myometrial invasion by tumor & can demonstrate LAP.
Pelvic Inflammatory Disease
Causes :
Complication of pelvic surgery, child bearing, appendicitis,
diverticulitis, abortion. IUCD
US is the first imaging modality:
1. Cystic or complex mass lesion with septations
2. tubular cystic lesion of hydro or pyosalpinx
3. Free pelvic fluid
Endometriosis
US : cystic or complex mass lesion in adnexal region or pouch of
Douglas (chocolate cysts)+/- free pelvic fluid
MRI : characteristic appearance of increased signal in T1 WI
Detection of IUCD:
US: shows echogenic linear structure within the endometrial cavity.
If US did not show the IUCD it might be displaced outside the uterus
into abdominal cavity , plain film abdomen is required for localization
Hysterosalpingography:
Contrast injection into the uterus through cervical cannula to show the
endometrial cavity & fallopian tubes & follow the free spillage of
contrast into the peritoneal cavity
Indication :
1-infertility to assess tubal patency,
2-assessment of congenital anomalies of the uterus (arcuate Ut.,
bicornuate Ut., unicornuate ut.)
Obstetrics
US is the modality of first choice
No evidence of biological hazards on the growing embryo from US
For the detection of early pregnancy, TAS or TVS used Transvaginal
approach diagnoses early pregnancy & fetal cardiac pulsation one week
earlier than TAS with better resolution
US in 1
st
trimester:
The patient should have full bladder.
5 wk: the gestational sac appears as rounded cystic structure inside
uterus. MSD (mid sac diameter ) used for GA assessment
6 wk: fetal pole seen as linear echogenic structure CRL (crown rump
length) used for GA assessment until 12 wk gestation.
7 wk : fetal cardiac pulsation identified
Measurement of fluid on the back of fetal neck made 10-14 wk. it is
useful for detection of chromosomal disease especially Down syndrome.
US in 2
nd
& 3
rd
trimesters:
BPD (biparietal diameter): used from 12 WK onward, the falx
produces mid line echo on either sides of which are the thalami seen as
rounded hypoechoic structures. This is the best section to measure the
BPD from the inner table to the outer table of the apposing parietal
bones
FL (femoral length): used after 14 WK gestation , useful whenever
the BPD can not be measures as in anencephaly
The best time for assessment of BPD & FL is at 18-20 WK
Comparing the BPD & FL with standard growth charts , an estimate
of the gestational age can be made
Abdominal circumference used whenever suspect growth
retardation as the fetal trunk growth & the fetal body weight are the first
to be affected
The section should include the stomach & the umbilical vein as it
passes through the liver
Comparing the AC with BPD , FL & HC on growth chart will
distinguish symmetrical from asymmetrical IUGR
The placenta:
• Placenta can be identified from the 9th WK gestation as high level
echo structure
• Early in pregnancy till 30th WK gestation the placenta may be seen in
close relation to the internal os
• The diagnosis of placenta previa should be made after 30 WK when
placenta seen to cover totally or partially the internal os
• In abruptio placentae, US can help in diagnosis if a collection of blood
is seen separating the amniotic membranes from the uterine surface.
• Retro membranous hemorrhage may be seen in early pregnancy as an
echo free lenticular structure that usually resolves spontaneously in few
weeks
Large for Date uterus:
Inaccurate date
Multiple pregnancies readily diagnosed by US.
Molar pregnancy
Polyhydramnios
Association of pregnancy with uterine or ovarian masses
Trophoblastic diseases
Range from benign H.mole to malignant chorio CA
Can not distinguish benign from malignant lesions on the bases of
US
The most common type is the complete molar pregnancy , the
uterus is filled with multiple small vesicle like structure
Less common type is partial H mole where fetal parts may be seen
as well
In 1/3 of pt. theca lutein cysts may be associated.
Polyhydramnios
Maternal DM
Congenital anomalies present in 20% of cases :
1. Neural tube defect
2. Esophageal ,duodenal or jujenal atresia
3. Fetal hydrops fetalis
4. Normal twin pregnancy
Small for date uterus
Wrong date
Symmetrical IUGR : early in pregnancy ,both the BPD & AC are
affected symmetrically , associated with congenital anomalies &
intrauterine infections
Asymmetrical IUGR : at the third trimester , affect the body > head ,
secondary to placental in sufficiency
Fetal congenital abnormalities:
anencephaly is the most common fetal congenital anomalies ,
should be identified in 12 WK gestation to allow therapeutic abortion
There is absence of the fetal skull vault with prominent orbit & facial
structure
The lateral ventricles are identified from 16 WK The choroid plexus
seen as echogenic mass occupying the posterior aspect of the lat. V.
Hydrocephaly is diagnosed when the distance between lateral walls of
the lateral V. is more than 50% of BPD
Lumbosacral spina bifida usually associated with meningocele +
hydrocephaly
Congenital diaphragmatic hernia & some congenital heart diseases
can be diagnosed by US.
duodenal atresia is the most common anomalies of the GIT
associated with Polyhydramnios + double bubble appearance
Omphalocele & gastroschiasis can be diagnosed by US.
Bilateral Renal agenesis or dysplastic kidneys result in sever
oligohydramnios with absence of fetal bladder structure. Unilateral
anomalies with normal other kidney are associated with normal
amniotic fluid volume
Posterior urethral valve results in massive dilatation of the both
PCS, ureters & UB
PUJ obstruction results in dilatation of the PCS alone
Fetal death:
Failure to identify heart beating & fetal movement from 7
th
week suggest
fetal death. If there is doubt, repeat the scan after suitable interval.
A blighted ovum is diagnosed if the size of gestational sac is > 3cm with
no fetal structures seen within it.
ECTOPIC PREGNANCY
• Positive PT in the absence of intrauterine gestational sac highly
suggests ectopic pregnancy. The presence of concomitant intra & extra
uterine pregnancy is very rare
• US shows thick endometrium + adnexal mass lesion +/-fetal pole
inside the mass +/-free pelvic fluid if it ruptures
Retained products of conception can be readily diagnosed by US.