IMAGES Chapter 37 - Obstetric Ultrasound Flashcards
IDENTIFY THIS SIGN.
[FIGURE 37.4.]
DOUBLE BLEB SIGN
The double bleb is formed by the yolk sac (white arrowhead) and the amniotic sac (black arrowhead)
suspended in the fluid of the early chorionic sac.
The embryo is seen as a tiny disc-like structure (arrow) within the amniotic sac.
Early cardiac activity can frequently be observed in the tiny embryo.
IDENTIFY.
[FIGURE 37.5.]
CORPUS LUTEUM
A. Transvaginal color Doppler image of the ovary reveals a 3-cm cyst surrounded by an intense ring of vascularity (“ring of fire”) characteristic of the corpus Luteum. The corpus luteum secretes hormones essential for the development of the pregnancy.
B. Transvaginal image of the ovary shows the collapsed cyst appearance of the corpus luteum (between arrowheads ) that occurs just after ovulation.
Note the follicles (arrow) that confirm location of the structure on the ovary.
C. Being highly vascular, the corpus luteum is prone to internal hemorrhage creating a hemorrhagic ovarian cyst (between arrowheads). Note the echogenic fluid and clot (arrow) within the cyst.
D. A hemorrhagic corpus luteal cyst (between arrowheads) may enlarge to become a prominent pelvic structure and be a source of adnexal pain in early pregnancy. This corpus luteal cyst measures 5 cm in diameter. Blood clots (arrow) within the cyst may simulate an ectopic pregnancy containing
an embryo.
IDENTIFY.
A 7-week embryo has a prominent cystic structure
(arrow) within the cranium. [FIGURE 37.6.]
NORMAL CYSTIC RHOMBENCEPHALON
This is the normal cystic phase of development of the rhombencephalon that is seen between 6 and 8 weeks gestational age.
Development of the rhombencephalon results in normal structures in the posterior fossa
IDENTIFY.
A 10-week embryo shows a prominent bulge (arrow) at the level of the umbilicus. [FIGURE 37.7]
NORMAL MIDGUT HERNIATION
This is caused by the normal herniation of the midgut into the base of the umbilical cord that occurs between 9 and 11 weeks gestation. This normal structure should not exceed 1 cm in size.
DIAGNOSIS?
An empty gestational sac measuring 27 mm in mean sac diameter (MSD) is demonstrated within the uterus by transvaginal US.
The margin of the sac is irregular in contour, and the decidual reaction is poorly defined and only weakly echogenic.
Color Doppler shows blood flow only in the myometrium. [FIGURE 37.8.]
ANEMBRYONIC PREGNANCY
In a normal intrauterine pregnancy, a yolk sac should always be demonstrable by transvaginal US when the MSD exceeds 8 mm and an embryo should be seen when the MSD exceeds 16 mm.
Doppler US should be used with caution, especially in the first trimester, and only when the pregnancy is believed to be abnormal.
IDENTIFY. [FIGURE 37.10.]
PSEUDOGESTATIONAL SAC
Fluid within the endometrial
cavity in a patient with an ectopic pregnancy mimics an intrauterine gestational sac.
The intrauterine fluid (arrow) is echogenic and particulate indicative of blood.
The decidual reaction (arrowhead) will be
present whether the pregnancy is intrauterine or ectopic.
DIAGNOSIS? [FIGURE 37.11.]
SUBCHORIONIC HEMORRHAGE
Hemorrhage (black arrowhead) is seen in the uterine cavity between the decidua capsularis
and the decidua vera. Some of the blood is clotted and appears more echogenic (white arrowhead) than the liquid blood.
A live embryo (arrow) was present within its amniotic sac.
DIAGNOSIS? [FIGURE 37.9.]
A. Transvaginal US in a longitudinal
plane demonstrates an empty uterus
(between calipers, + , x) in a pregnant patient.
Echogenic blood (arrow) distends the cul-de-sac.
ECTOPIC PREGNANCY
B. Transverse transvaginal image reveals a tubal ring sign (arrow) in the right adnexa highly indicative of ectopic pregnancy. U, uterus (between
calipers, + ).
C. Color Doppler image of a tubal ectopic pregnancy shows a tubal ring sign with a “ring of fire” made up of prominent blood vessels.
Note the similarity in appearance to the corpus luteal cyst in Figure 37.5A . Differential is made by real-time US determination of the location of the mass as arising from the ovary or as being separate from the
ovary. This differentiation is not always possible.
IDENTIFY. [FIGURE 37.12]
A. Transverse image of the uterus in a woman with continuing bleeding following a spontaneous
abortion.
B. Transverse color Doppler image of the uterus in the same patient.
RETAINED PRODUCTS OF CONCEPTION
A. Transverse image of the uterus in a woman with continuing bleeding following a spontaneous
abortion reveals echogenic material (arrow) representing retained placenta and echolucent material (arrowhead) representing blood and clots
within the uterine cavity.
B. Transverse color Doppler image of the uterus in the same patient documents continuing blood flow to the retained placenta.
DIAGNOSIS? [FIGURE 37.13.]
HYDATIDIFORM MOLE
A. Transvaginal US shows the “snowstorm” appearance of a molar pregnancy (between arrowheads) filling the uterine cavity in the first trimester.
B. In another patient examined early in the second trimester, more discrete cysts are seen within the molar tissue (arrowheads). m, myometrium.
DIAGNOSIS? [FIGURE 37.14]
Transabdominal image demonstrates the ovary (between calipers, +) to be greatly enlarged by numerous cysts in this patient with a twin pregnancy following infertility therapy.
The β -hCG level was greatly elevated.
This ovary measured 16 × 12 × 8 cm in size.
THECA LUTEIN CYSTS
The ___ is measured from the top of the head to the bottom of the torso (between cursors, + ). [FIGURE 37.15]
CROWN-RUMP LENGTH (CRL)
IDENTIFY THIS FETAL MEASUREMENT. [FIGURE 37.17]
ABDOMINAL CIRCUMFERENCE
The correct plane of measurement of the abdominal circumference is an axial plane showing
a round abdomen at the level of the umbilical vein
(arrowhead) junction with the left portal vein.
[FIGURE 37.16] Axial image of the fetal cranium
demonstrates the paired thalami (arrowhead) on either side of the midline third ventricle (long arrow).
The _____ is measured in this plane from the outer surface of the near cranium to the inner surface of the far cranium (+ , cursors).
The _________ is measured as an outer perimeter measurement of the cranium in the same plane
(elliptical dashed line, x cursors).
TRANSTHALAMIC (BIPARIETAL DIAMETER/HEAD
CIRCUMFERENCE [BPD/HC]) PLANE.
1. BPD
- HEAD CIRCUMFERENCE
IDENTIFY THIS FETAL MEASUREMENT. [FIGURE 37.18]
FEMUR LENGTH (FL)
The FL is the measurement of
the ossified portion of the femoral diaphysis
(between calipers, + ).
This is an Umbilical Artery Doppler tracing.
[FIGURE 37.19]
FIGURE A: NORMAL OR ABNORMAL ?
FIGURE B: NORMAL OR ABNORMAL ?
FIGURE A: NORMAL
FIGURE B: ABNORMAL
A. Spectral Doppler tracing from an umbilical artery shows a normal pattern with forward flow maintained throughout diastole and a low vascular resistance
with RI = 0.58.
B. Spectral Doppler in a severely growth retarded
fetus shows a high vascular resistance pattern with fl ow toward the placenta during systole and reversal of blood fl ow direction in diastole (arrowhead). This finding is highly indicative of severe fetal distress.
This fetus died 4 days after this examination.
DIAGNOSIS ? [FIGURE 37.20]
The cervix is best evaluated
with a _______ view with the bladder (B) empty. The transducer is aimed down the long axis of the vagina (V). The cervix, measured between the internal os and the external os (arrowheads), is shortened
to 9 mm in this patient with a history of multiple spontaneous abortions in the second trimester.
The cervix is also dilated allowing amniotic
fluid ( asterisk ) to enter the endocervical canal.
The fetal head ( H ) is presenting at the internal cervical os.
**CERVICAL INCOMPETENCE;
TRANSLABIAL view**
[FIGURE 37.21]
A transabdominal scan demonstrates a \_\_\_\_\_\_\_\_ (P) and the insertion site of the cord onto the placenta (arrowhead).
The ____________________\_
(arrows) appears as a network of tubular lucencies beneath the placenta. A, amniotic cavity.
NORMAL PLACENTA
RETROPLACENTAL COMPLEX OF VEINS
DIAGNOSIS? [FIGURE 37.23]
PLACENTAL ABRUPTION
The placenta (P) is displaced away from the wall of the uterus (U) by an echogenic hematoma (H).
Note the absence of visualization of the retroplacental complex of veins. A, amniotic cavity.
DIAGNOSIS? [FIGURE 37.22]
PLACENTA PREVIA
Transabdominal US shows a normal cervix (between cursors, +) measuring 34 mm. The placenta (P) covers
the internal os. A, amniotic cavity; B, bladder; V, vagina.
IDENTIFY THIS NORMAL STRUCTURE.
[FIGURE 37.24]
NORMAL UMBILICAL CORD
A. Color Doppler image shows the normal spiral (“barber pole”) appearance of the three-vessel
umbilical cord as it extends from the placenta.
B. Transverse color Doppler image through the fetal pelvis shows the bladder (B encompassed by
the two umbilical arteries (arrowheads) as they course to join the fetal internal iliac arteries. This view provides a handy way to confirm the presence of a three-vessel cord with two umbilical arteries.
DIAGNOSIS ? [FIGURE 37.25]
AMNIOTIC BAND SYNDROME
The forearm (arrowhead) of a fetus at 15 weeks gestational age is _entangled within fibrous bands_ (arrows) that extend across the chorionic cavity (C).
IDENTIFY. [FIGURE 37.26]
AMNIOTIC SHEET
A. A fibrous band covered by chorioamniotic membranes (arrow) extends across the amniotic cavity. The uterine synechia forms a shelf-like structure that partially compartmentalizes the uterine cavity. The fetus has free access to both compartments.
B. The characteristic free edge ( arrow ) of the amniotic sheet is demonstrated.
DIAGNOSIS ? [FIGURE 37.27]
NUCHAL SKIN THICKENING
Transcerebellar view of the fetal cranium shows thickening of the nuchal fold (between cursors, +)
to 8 mm. The measurement is made between the fetal skull and the skin surface.
The normal measurement should not exceed 6 mm in the second trimester.
This fetus proved to have Down syndrome.
What are the landmarks in the transcerebellar
plane (in cranial ultrasound) ? [FIGURE 37.29]
thalami (t), third ventricle (arrow),
and cerebellar hemispheres (c).
The cisterna magna (between arrowheads) is measured
from the vermis to the occiput. The normal cisterna magna measures 2 to 11 mm throughout pregnancy.
WHAT IS THE IMAGING PLANE IN THIS PICTURE?
DIAGNOSIS?
[FIGURE 37.28]
TRANSVENTRICULAR PLANE
EARLY VENTRICULOMEGALY
The choroid plexus (skinny arrow) hangs dependently in the atrium of the downside lateral ventricle. The ventricular atrium is measured from its medial wall to its lateral wall (between cursors, +).
The normal ventricular atrium does not exceed 10 mm in width at any time during pregnancy.
The diameter of the atrium in this case measures
12 mm indicating ventriculomegaly.
This fetus has a spina bifida defect with associated Arnold–Chiari II malformation as the cause of ventriculomegaly.
Note the bossing of the frontal bones (thick arrow)
giving the outline of the cranium an appearance similar in shape to a lemon (lemon head).
DIAGNOSIS ? [FIGURE 37.30]
VENTRICULOMEGALY
An axial image of the fetal brain, an infant with aqueduct stenosis, demonstrates marked enlargement
of the lateral ventricles (V).
The _falx_ (arrowhead) is seen as an echogenic stripe in the midline. A _rind of cortex_ (arrow) is present. _These latter two findings differentiate ventriculomegaly from hydranencephaly and holoprosencephaly._
DIAGNOSIS ? [FIGURE 37.31]
A sagittal image through the head of a fetus.
The mouth and the lips are evident (arrowhead).
ANENCEPHALY
A sagittal image through the head of a
fetus demonstrates absence of the cranial vault (thick arrow) above the level of the eye (skinny arrow).
The volume of amniotic fluid (A) is increased.
Polyhydramnios is common in the presence of anencephaly. Arm, fetalarm.
DIAGNOSIS ? [FIGURE 37.32]
Axial US image through the fetal skull
ENCEPHALOCOELE
Axial US image through the fetal skull demonstrates herniation of brain tissue (B) through a large defect
(long arrows) in the skull, forming an occipital encephalocele (between arrowheads). The intracranial contents are reduced, and the biparietal diameter (between cursors, +) is less than expected for
gestational age because of the encephalocele.
FIGURE A.: NORMAL SPINE OR SPINA BIFIDA ?
FIGURE B.: NORMAL SPINE OR SPINA BIFIDA ?
[FIGURE 37.33]
Figure A. NORMAL SPINE
Figure B. SPINA BIFIDA
A. Normal spine. Posterior transverse image through a normal fetal spine at the L4 to L5 level demonstrates normal converging orientation of the ossified portions of the lamina (arrows). The skin overlying the posterior aspect of the vertebra is intact (arrowhead).
B. Spina bifida. Posterior transverse image through a spina bifida defect demonstrates abnormal divergence of ossified portions of the lamina (arrows) posteriorly. The skin surface ends abruptly (arrowheads) at the open defect. IC, iliac crest.
DIAGNOSIS ? [FIGURE 37.34]
Image through the cranium of a fetus.
ALOBAR PROSENCEPHALY
Image through the cranium of a fetus reveals a single large midline ventricle (V) and fused thalami (arrow).
A thin rim of cortex (arrowhead) is present.
These findings are characteristic of alobar holoprosencephaly.
The fetal face should be examined for associated defects such as midline cleft and proboscis.
DIAGNOSIS ? [FIGURE 37.35]
Axial sonogram through the brain of a near-term fetus.
HYDRANENCEPHALY
Axial sonogram through the brain of a near-term fetus demonstrates two massive ventricles (V), a well defined midline falx (arrowhead) and total absence of detectable cortical tissue (arrow).
These findings are characteristic of hydranencephaly.
DIAGNOSIS ? [FIGURE 37.36]
Coronal plane image.
DANDY WALKER MALFORMATION
Coronal plane image demonstrates cystic enlargement of the posterior fossa (arrow). The lateral ventricles (V) are enlarged indicating associated hydrocephalus.
DIAGNOSIS ? [FIGURE 37.38]
A multiseptated cystic mass (C) extends over the occipital region of the fetal skull.
CYSTIC HYGROMA
Cystic hygroma is differentiated from occipital cephalocele by demonstration of the midline
septum (arrow) due to the nuchal ligament and by absence of a bony defect in the skull.
Figure A: Normal Face View or Cleft Lip ?
Figure B: Normal Face View or Cleft Lip ?
[FIGURE 37.37]
**Figure A: Normal Face View
Figure B: Cleft Lip
A. Normal face view.** Coronal view of a normal fetal face (“up your nose”view) shows both nares (arrow), an open mouth (arrowhead) and the muscles of the upper (L) and the lower (LL) lips.
B. Cleft lip. Matching coronal view of another fetus reveals a cleft (thick arrow) in the left upper lip extending into the left nares (skinny arrow). The mouth is slightly open. The lower lip (LL) is apparent. An arm (A) extends across the face.
DIAGNOSIS ? [FIGURE 37.39]
A. A transverse image through the fetal thorax at the level of a four-chamber view of the heart.
B. Transverse US of the fetal abdomen
FETAL HYDROPS
A. A transverse image through the fetal thorax at the level of a four-chamber view of the heart (arrow) demonstrates large bilateral pleural effusions (e). The skin surrounding the thorax is markedly thickened (T).
B. Transverse US of the fetal abdomen also
shows marked skin thickening (T).
DIAGNOSIS ? [FIGURE 37.40]
CONGENITAL DIAPHRAGMATIC HERNIA
Axial plane image of the fetal thorax stomach (St) and small bowel (between arrows) herniated into the left thorax. The heart (H) is shifted markedly
into the right thorax and is abnormally rotated.
Only a small volume of compressed right lung (L) is present.
Severe pulmonary hypoplasia is likely and the prognosis for this fetus is grim. The spine (S) is seen posteriorly.
DIAGNOSIS ? [FIGURE 37.41]
An echogenic solid-appearing mass (between arrows) is seen in the right thorax displacing and compressing the heart (H). A small portion of the compressed left lung (L) is evident.
CYSTIC ADENOMATOID MALFORMATION
The appearance is characteristic of
type III, cystic adenomatoid malformation.
IDENTIFY THIS ULTRASOUND VIEW. [FIGURE 37.42]
NORMAL FOUR-CHAMBER HEART VIEW
Axial sonogram through the fetal chest demonstrates the normal heart and fluid-filled lungs in an 18-week fetus. The right ventricle (rv) and the left ventricle
(lv) are approximately equal in size, as are the right atrium (ra) and the left atrium (la).
The heart normally occupies about one-third of
the cross-sectional area of the thorax.
The developing lungs are echogenic.
The spine (S) is seen posteriorly. rl, right lung; ll, left lung.
IDENTIFY THIS SIGN. [FIGURE 37.43]
DOUBLE BUBBLE
Fluid distension of the stomach dilated (St) and the duodenal bulb (D) is caused by obstruction at the level of the descending duodenum.
DIAGNOSIS ? [FIGURE 37.45]
HYDRONEPHROSIS
Coronal plane image through the fetal abdomen reveals bilateral hydronephrosis (skinny arrows) resulting
from posterior urethral valves.
Calyces and the renal pelvis are dilated. Both kidneys (between short arrows) are normal in size.
DIAGNOSIS ? [FIGURE 37.44]
SMALL BOWEL OBSTRUCTION
Ileal atresia was the cause of markedly dilated loops of small bowel seen throughout the abdomen.
DIAGNOSIS ? [FIGURE 37.46]
Coronal plane image in a 22-week fetus.
AUTOSOMAL RECESSIVE POLYCYSTIC
KIDNEY DISEASE
Coronal plane image in a 22-week fetus shows two markedly enlarged, highly echogenic kidneys
(between cursors,+,x) filling and distending
the abdomen. Each kidney exceeded 5 cm in length. Severe oligohydramnios was present. This appearance is characteristic of the infantile form of autosomal recessive polycystic disease.
IDENTIFY THIS NORMAL STRUCTURE.
[FIGURE 37.47]
NORMAL UMBILICAL CORD INSERTION SITE
A. Normal. Axial image through the fetal abdomen at
the level of the umbilicus shows the normal cord insertion site (arrowhead).
DIAGNOSIS ? [FIGURE 37.4]
GASTROSCHISIS
Axial image through the abdomen of another fetus shows loops of bowel (short fat arrow) extending through a defect in the anterior abdominal wall (long skinny arrow) just to the right of the insertion site of the umbilical cord (arrowhead).
DIAGNOSIS ? [FIGURE 37.47.]
OMPHALOCELE
Axial image of another fetus at the level of the umbilicus shows liver herniating through a defect (between arrowheads ) in the anterior abdominal wall. The defect involves the umbilical cord (skinny arrow).
A covering membrane (short fat arrow) is easily seen because it is outlined by ascites (a) within the omphalocele and the amniotic fluid.
DIAGNOSIS ? [FIGURE 37.48]
A longitudinal image of the femur (between cursors, +)
MICROMELIC DWARF
A longitudinal image of the femur (between cursors, +) demonstrates poor mineralization, central bowing (arrowhead), and length that is markedly short for gestational age.
