RADIOLOGY IN OBSTETRICS EMERGENCIES

1. Obstetrics Emergencies
By
Dr. LOHITH VARMA
PG RADIODIAGNOSISMODERATOR:
Dr. SHIVA SIR

2.  Implantation bleeding
 Miscarriage
 Ectopic pregnancy
 Sub chorionic Hemorrhage
 Molar pregnancy
 Problems with the cervix, such as a cervical infection, inflamed cervix or growths on the
cervix
1st TRIMESTER VAGINAL BLEEDING

3. 2ND / 3RD TRIMESTER VAGINAL BLEEDING
 Incompetent cervix
 Miscarriage
 Placental abruption
 Placenta previa
 Vasa Previa
 Preterm labor
 Uterine rupture
 Problems with the cervix, such as a cervical infection, inflamed cervix or growths on the cervix

4. NORMAL VAGINAL BLEEDING NEAR THE END OF PREGNANCY
 Light bleeding, often mixed with mucus, near the end of pregnancy could be a sign that labor is
starting. This vaginal discharge is pink or bloody and is known as bloody show.

5. IMPLANTATION BLEEDING
1. It is physiological
2. Small amount of spotting or bleeding
3. Seen at 10-14 days after fertilization
4. At the time of the missed menstrual period.
5. Due to implantation of fertilized egg in the decidua.
6. Diagnosis of exclusion and timing.
7. No intervention is indicated.

6. MISCARRIAGE
 A miscarriage is the spontaneous termination of a pregnancy before 20 weeks of
gestation.
 Fetal death after week 20 is termed fetal death in utero (FDIU.

7. First trimester:
(1)Genetic factors (50%).
(2) Endocrine disorders (LPD, thyroid abnormalities, diabetes).
(3) Immunological disorders (autoimmune and alloimmune).
(4) Infection.
(5) Unexplained.
Second trimester:
(1) Anatomic abnormalities—
(a) Cervical incompetence (congenital or acquired).
(b) Müllerian fusion defects (bicornuate uterus, septate uterus).
(c) Uterine synechiae.
(d) Uterine fibroid.
(2) Maternal medical illness.
(3) Unexplained

8. THREATENED MISCARRIAGE
In this , process of miscarriage has started but has not progressed to a state from which recovery is
impossible .
Cervical Os is closed.
USG -TVS
(1) A well-formed gestation ring with central echoes from the embryo indicating healthy fetus
(2) Observation of fetal cardiac motion. With this there is 98% chance of continuation of pregnancy.
(3) A blighted ovum is evidenced by loss of definition of the gestation sac, smaller mean gestational
sac diameter, absent fetal echoes and absent fetal cardiac movements

10. Some features suggestive of a poor outcome:
1. Fetal bradycardia: <80-90 bpm
2. Small mean G sac diameter.
3. Large and calcified yolk sac of more than 7 mm
4. Small or irregular gestational sac: MSD/CRL <5 mm
5. Large sub chorionic hemorrhage more than 2/3 of gestational sac
6. Expanded amnion sign (an abnormally large amniotic cavity)
7. Absent or poor decidual reaction

11. INEVITABLE MISCARRIAGE
It is the clinical type of abortion where the changes have progressed to a state from where
continuation of pregnancy is impossible.
Dilated internal os of the cervix.

12. INCOMPLETE MISCARRIAGE
When the entire products of conception are not expelled, instead a
part of it is left inside the uterine cavity, it is called incomplete
miscarriage.
Ultrasonography—reveals echogenic material (products of
conception) within the cavity.
COMPLETE MISCARRIAGE
When the products of conception are expelled en masse, it is called
complete miscarriage.
Cervical os is closed
TVS/USG :
Reveals empty uterine cavity.

14. MISSED MISCARRIAGE
When the fetus is dead and retained inside the uterus for a variable period, it is called missed
miscarriage or early fetal demise.
Ultrasonography reveals an empty sac early in the pregnancy (OR) the absence of fetal cardiac
motion and fetal movements.

15. SEPTIC ABORTION
Any abortion associated with clinical evidences of infection of the uterus and its contents is
called septic abortion.
Ultrasonography
1.Intrauterine retained products of conception.
2.Physometra. (Gas in uterus)
3. Foreign body—intrauterine or intra-abdominal,
4. Free fluid in the peritoneal cavity or in the pouch of Douglas (pelvic abscess).

17. ECTOPIC PREGNANCY

19. MAIN RISK FACTORS :
1. History of ectopic pregnancy
2. Tubal surgery
3. Pelvic inflammatory disease
BETA-HCG MEASUREMENT:
β-HCG doubles every 2 to 3 days and it decline after 8 weeks.
β-HCG and mean sac diameter (MSD) increase proportionally until the 8th week.
The discriminatory level of Beta-hCG: the level above which an imaging scan should reliably visualize a
gestational sac (GS) within the uterus in a normal intrauterine pregnancy (IUP) is:
2000 mIU/mL for transvaginal ultrasonography (TVS)
6000-6500 mIU/mL for a transabdominal ultrasonography (TAS)

20. No single serum Beta-hCG level is diagnostic of an EP. Serial levels are necessary to differentiate
between normal and abnormal pregnancies

21. NORMAL INTRAUTERINE PREGNANCY (IUP)
Gestational sac (GS) :
1. • Filled with chorionic fluid
2. • Intradecidual sign - small collection of fluid that is
eccentrically located within the endometrium and is
surrounded by a hyperechoic ring
3. • Double decidual sign- Two concentric echogenic
rings that has been termed the double sac sign or
double decidual sign formed by decidua parietalis
(hyperechoic), fluid in the uterine cavity
(hypoechoic)and decidua capsularis (hyperechoic)
4. • Doppler- detection of peritrophoblastic
flow. Intradecidual PSV>= 15cm/sec & RI <=0.55
5.

22. SONOGRAPHIC FEATURES OF ECTOPIC PREGNANCY
A. Fallopian tube :
• An adnexal mass that is separate from the ovary is the most common finding of a tubal pregnancy
seen in up to 89%–100% of patients. Associated yolk sac, living embryo and independent movement
form the ovary increases the specificity.
• The tubal ring sign is the second most common sign of a tubal pregnancy. The tubal ring sign
describes a hyperechoic ring surrounding an extra uterine gestational sac.
• ·A related finding is the “ring of fire” sign, which is recognized by peripheral hypervascularity of the
hyperechoic ring. It is a nonspecific finding and may also be seen in a normal maturing follicle or a
corpus luteal cyst.
• Determining the location of this type of flow, whether it is within the ovary or outside the ovary, is
most important to distinguish between an EP and a corpus luteum. This sign is most helpful when no
definite EP is seen on gray-scale images.

24. B. Ovary:
Corpus luteum is the most common finding in the ovary.
About 80% of EP is found on the same side as the corpus
luteum.
Contralateral implantation occurs in up to one-third of
cases
• Hypoechoic, centrally cystic cyst in the ovary. On color
Doppler imaging, there is a characteristic "ring of fire"
appearance to the cyst.
• In the setting of an intra-uterine pregnancy (gestational
sac with a yolk sac +/- embryo), this is cystic lesion is
characteristic of a corpus luteum.
• In the absence of IUP , it may still be a corpus luteum
cyst, but one should maintain suspicion for a possible
ectopic pregnancy.

25. According to a study by Rottem, et al, three criteria can aid in distinguishing between
an ectopic gestation and corpus luteum cyst:
1.The echogenicity of a suspected finding relative to the ovary
2.The presence or absence of flow
3.The relationship of the sign to an intentionally displaced ovary
According to published reports,
1.The tubal ring of an ectopic is usually more echogenic than the ovarian parenchyma, and may be more
echogenic than the endometrium.
2.In contrast, the walls of the corpus luteum usually appear less echogenic or about the same as the ovarian
parenchyma. This can be used as an ancillary sonographic finding.

26. C. Uterus :
Intrauterine findings of an ectopic pregnancy
include
1. Normal endometrium
2. Pseudo– gestational sac - represents a thick
decidual reaction surrounding intrauterine fluid.
10% of EP demonstrates a pseudo–gestational
sac.
3. Trilaminar endometrium – Normally seen in late
proliferative phase of the normal menstrual
cycle. Absence of a true GS in the presence of a
trilaminar endometrium on US images is highly
suggestive of an EP.
4. Thin-walled decidual cyst- is found at the
junction of the endometrium and the myometrium.
It can be seen in both normal and abnormal
pregnancies. The thin wall of the decidual cyst
differentiates it from a true GS
Uterine findings in EP.
Gray scale USG (A) and (B) show oval cystic
focus with single echogenic ring and thickened
endometrium representing pseudo gestational
sac. (C) Significant thickening of endometrial
echo in known case of EP suggesting
endometrial cast

29. D. Extra uterine :
• Extra uterine findings of EP include
pelvic free fluid, hematosalpinx, and
hemoperitoneum.
• Pelvic free fluid is seen in 50-75% of
EP
• Pelvic hemorrhage (Echogenic
fluid) is a more specific finding, with
an 86%–93% PPV when β-hCG levels
are abnormal and raises concern for a
ruptured EP. Gray scale USG (A and B) showing complex solid right
adnexal mass (arrow) separate from the ovary with
echogenic pelvic free fluid (asterisk)
Suggestive of tubal EP rupture with hemoperitoneum.
Note made of intrauterine device (loop)

32. Ultrasound (A) of pelvis demonstrates gestational sac (yellow arrow) in left cornua with empty
endometrial cavity (black arrow). Coronal T2 TSE (B) and post gadolinium (C) confirmed the cornual
location of gestation sac

33. USG (A) and Sagittal T2W MRI (B) shows fetus with surrounding amniotic fluid in recto uterine
pouch outside the uterus representing abdominal EP.

34. USG (A), axial and sagittal T2W MRI (Band C) shows GS with fetus in the uterine cervix (arrow) and
associated endometrial thickening (U).

35. Gray scale USG (A) shows
intrauterine GS.
Gray scale (B) and doppler
USG (C) shows complex right
adnexal cystic mass (asterisk)
separate from the right ovary
(Arrow) suggestive of tubal EP.
USG (D) shows echogenic
fluid in the pelvis suggesting
rupture of tubal EP.

36. DIAGNOSIS CLINICAL CLUE USG Beta HCG Remarks
Early IUP H/O amenorrhea and vaginal
bleeding
No intrauterine GS or adnexal mass Positive Serial Beta-hCG - Normal doubling
Nonviable IUP H/O amenorrhea and vaginal
bleeding
Variable depending on the cause and
stage.
1. Irregular contour of sac
2. Decidual reaction <2 mm
3. Choriodecidual reaction not
echogenic
4. Absent double decidual sac
5. Low position
Positive Serial Beta-hCG- Decreasing, plateau
or slow rise
Rupture corpus luteal cyst 2nd half of menstrual cycle and
dominated by hemoperitoneum
Irregular thick walled cysts with
heterogenous contents and
hemoperitoneum.
Negative Laparotomy in unstable patients
irrespective of EP or Rupture CL cyst
Ovarian torsion Abrupt onset 1. Ovarian enlargement and edema
2. enlarged peripheral follicles
3. presence of ovarian mass
4. abnormal ovarian position
5. Iipsilateral uterine deviation
6. Cul de sac fluid
7. Absence of venous flow
8. Twisted pedicle sign
Negative MRI can be problem solving
PID
Cervical motion tenderness
Thick walled fallopian tube with or
without distension
Tuboovarian/pelvic abscess
Pelvic fat echogenicity
Free fluid
Negative CT/MRI for confirmation and to assess
the extent of disease to decide on
management
Appendicitis Right upper quadrant or flank pain
and tenderness in pregnancy due to
gravid uteru
MRI - modality of choice if US
equivocal
Enlargement (> 6mm) and
periappendiceal inflammation
Negative Most common surgical emergency in
pregnancy

37. Potential pitfalls
1.21% of EP demonstrate a β-hCG doubling time identical to that of intrauterine pregnancies (IUP)
2.Interstitial EP could be mistaken for cornual EP
3.Spontaneous abortion in progress mimics cervical EP
4.Visualization of IUP does not rule out EP- heterotopic pregnancy is possible albeit rare.
5.'Ring of fire' sign is a nonspecific finding and may also be seen in a normal maturing follicle or a corpus
luteal cyst.
6. Pelvic free fluid is seen in 50-75% of EP and does not necessarily imply tubal rupture. Non specific fluid is
also detected in 20% of all IUP
Pearls of EP diagnosis
1.Absence of IUP does not imply EP. It should just trigger a detailed search for an ectopic pregnancy
2.IUP should be seen on Transvaginal US with β-hCG levels of > 2000 mIU/mL.
3.Differentiate true GS from pseudo gestational sac by looking for 'Double decidual sign'
4.Intrauterine findings of an EP include normal endometrium, pseudo gestational sac, trilaminar endometrium
and thin-walled decidual cyst.
5.No single serum Beta-hCG level is diagnostic of an EP. Serial levels are necessary to differentiate between
normal and abnormal pregnancies and to monitor resolution of EP once therapy has been initiated
6.If β-hCG levels increase by less than 50% during a 48-hour period, there is almost always a nonviable
pregnancy either intra- or extra uterine.
7.An adnexal mass that is separate from the ovary is the most common finding of a tubal pregnancy seen in
up to 89%–100% of patients

38. CERVICAL INCOMPETENCE
 The retentive power of the cervix (internal os) may be impaired functionally and/or anatomically .
CAUSES:
 (a) Congenital Uterine anomalies.
 (b) Acquired (iatrogenic) — common, following:
(i) D and C operation,
(ii) induced abortion by D and E (10%),
(iii) vaginal operative delivery through an undilated cervix.
(iv) amputation of the cervix or cone biopsy of trachelectomy.
 (c) Others —multiple gestations, prior preterm birth.

42. SUBCHORIONIC HEMORRHAGE
 Subchorionic hemorrhage occurs when there is perigestational hemorrhage and blood collects
between the uterine wall and the chorionic membrane in pregnancy. It is a frequent cause of first and
second trimester bleeding.
ULTRASOUND
 Crescentic collection with elevation of the chorionic membrane
 Depending on the time elapsed since bleeding, the collection will have variable echotexture
 acute: hyperechoic and may be difficult to differentiate from the adjacent chorion.
 subacute-chronic: decreasing echogenicity with time
 In almost all cases there is an extension of the hematoma towards the margin of the placenta.

43. QUANTIFICATION
In early pregnancy, a sub chorionic
hemorrhage is considered as-
Small : <20% of the size of the sac.
Medium-sized : 20-50% sac
Large : >50-66% of the size of the
gestational sac.
Large hematomas by size and volume
(>50 mL) worsen the patient's prognosis .

44. A single living foetus of about 13 weeks gestation with a normal heartbeat (154 b/min).
A hypoechoic fluid collection is seen extending between the uterine wall and the chorionic
membrane posteriorly extending till the placental margins and crossing the internal os.

45. PLACENTAL IMAGING IN EMERGENCY
 1. PLACENTA HEMATOMA
 2. PLACENTAL ABRUPTION
 3.PLACENTA PREVIA
 4. VASA PREVIA
 5. PLACENTA ACCRETA , INCRETA AND PERCRETA.

46. PLACENTAL HEMATOMA
1. Placental hematomas can occur on the fetal (preplacental or
subchorionic) side or maternal (retroplacental) side or be centered
within the placenta.
2. At US, placental hematomas appear as well-circumscribed masses with
echogenicity that varies according to chronicity.
3.
4.Doppler interrogation should reveal absence of internal blood flow; this
finding allows differentiation of hematomas from other placental masses.
Hypoechoic or anechoic Acute phase
Heterogeneously echogenic Sub- acute phase
Anechoic Chronic phase.

48. Fetal prognosis depends upon:
• size and (ii) the type of the hematoma.
• Retroplacental hematoma has got worst prognosis with high fetal mortality
(50%).
• Subchorionic smaller sized hemorrhages have less (10%) fetal mortality.
• Subamniotic is clinically less significant.

49. PLACENTAL ABRUPTION :
Placental abruption represents premature separation of the normally placed placenta from the uterine
wall.
Third-trimester abruption is associated with an increased risk of preterm delivery and fetal death .
Transvaginal may be required to accurately demonstrate the location of the placenta, particularly in
posteriorly located placentas but in TVS there is risk of premature rupture of membranes or to infection
when the membranes have already ruptured .
THE SONOGRAPHIC SIGNS OF PLACENTAL ABRUPTION:
1. Retroplacental hematoma
2. Separation and rounding of the placental edge.
3. Thickening of the placenta : often to over 5.5 cm.
4. Thickening of retroplacental myometrium.
5. Intra-amniotic echoes due to intra-amniotic hemorrhage.
6. Intramembranous clot in twins.

51. RETRO PLACENTAL

52. SUBCHORIONIC ABRUPTION

53. 1. Ultrasound is not sensitive for detection of acute /hyperacute placental abruption.
2. Acute hemorrhage is hyperechoic to isoechoic to placental tissue.
3. It becomes hypoechoic a week after it has occurred .
4. While resolving hematoma, appears sonolucent after the second week.

55. A crescenteric collection of
predominantly hypoechoic fluid
lifts the edge of the placenta (P)
away from the underlying
myometrium (M).The fluid
collection contains layering high-
attenuation material (arrowhead),
a finding consistent with blood.

56. PLACENTA PREVIA:
1. Placenta marginats @ 5mm / week.
2. In previa the placenta edge is close to internal Os.
3. Previa diagnosed in 2nd trimester can resolve by 3rd trimester.

61. LOW LYING PLACENTA

62. MARGINAL PLACENTA

64. CENTRAL PLACENTATION

65. ADHERENT PLACENTA :
The clinical condition when part of placenta
or entire placenta invades and is inseparable
from the uterine wall.
ACCRETA :
Placenta villi in direct contact with
myometrium.
INCRETA:
Subtype extending into the myometrium but
not to serosa.
PERCRETA:
Subtype extending to within one cell or
beyond the serosa.

66. PATHOPHYSIOLOGY:
• In normal pregnancy plaxenta attaches to the uterine wall and is
separated from the uterus by the Nitabuch’s fibrinoid layer.
• Partial or complete absence of the decidua basalis and
nitabuch’s layer results in adherent placenta
• This allows extravillous trophoblastic infiltration and villous tissue
develops deeply within the myometrium , including its
circulation, sometimes reach the surrounding pelvic organs.

67. CLINICAL RISK FACTORS:
1. Previous caesarean section.
2. Placenta Previa.
3. Previous hysterotomy.
4. Previous myomectomy.
5. Previous D and C.
BIOCHEMISTRY:
11-12 weeks of pregnancy :
hCG and its free hCG are lower.
PAPP-A is higher in the maternal serum of women with PAS disorders.
By contrast at 14-22 weeks :
Women presenting with a placenta previa are at higher risk of PAS disorders if serum beta hCG and
AFP are above 2.5 multiples of the median.
Creatine kinase can be used as as a biochemical marker in the diagnosis of placenta increta and
percreta.

68. USG:
1. Multiple , large irregular lucencies - Vascular lacunae are seen.
Contains turbulent flow.
2.LOss of retro placental hypoechoic zone, basal decidua and vascular bed.
3.Thinned out retroplacental myometrium. Less than 1 mm.
4. Disruption of uterine serosa. (Increta)
5. Bladder invasion. (Percreta)

70. COLOUR DOPPLER FEATURES :
1. Turbulent flow in the placental lagoons.
2. 2. Presence of Vascular lakes.
3. Hyper vascular bladder- uterine serosa interface.
4. Retro placental dilated vessels.
5. PI of uterine artery remains as in pregnancy , but gets elevated once it is removed.