Three-Dimensional Ultrasound: A Role in Early Pregnancy?


Organ/anatomical area

Present and/or normal?

Head

Present

Cranial bones

Midline falx

Choroid-plexus-filled ventricles

Neck

Normal appearance

Nuchal translucency thickness (if accepted after informed consent and trained/certified operator available)b

Face

Eyes with lensb

Nasal boneb

Normal profile/mandibleb

Intact lipsb

Spine

Vertebrae (longitudinal and axial)b

Intact overlying skinb

Chest

Symmetrical lung fields

No effusions or masses

Heart

Cardiac regular activity

Four symmetrical chambersb

Abdomen

Stomach present in left upper quadrant

Bladderb

Kidneysb

Abdominal wall

Normal cord insertion

No umbilical defects

Extremities

Four limbs each with three segments

Hands and feet with normal orientationb

Placenta

Size and texture

Cord

Three-vessel cordb


aAdapted with permission from ISUOG practice guidelines: performance of first-trimester fetal ultrasound scan. Ultrasound Obstet Gynecol 2013;41:102–113

bOptional structures





Prenatal Diagnosis of Congenital Anomalies by First-Trimester Ultrasound


Since the first reports demonstrating the feasibility of first trimester diagnosis of congenital anomalies in the late 1980s [1, 26, 27], mounting evidence indicates that accurate prenatal diagnosis of several of the more severe anomalies can be accomplished in the first trimester using high-resolution transvaginal ultrasonography [1, 2, 8, 23, 28]. Table 13.2 provides a summary of the studies published until 2014. These studies also provide evidence that, although early and accurate diagnosis of congenital anomalies is possible and allows early decision making, several anomalies may be missed if a second-trimester (or even a third trimester) scan is not performed. Examples of anomalies that can be missed by a first-trimester scan include vermian hypoplasia, agenesis of the corpus callosum, abnormalities of neuronal migration (e.g., lissencephaly, polymicrogyria, gray matter heterotopia), congenital lung anomalies, hypoplastic left heart, aortic and pulmonic valve stenosis, coarctation of the aorta, renal and bladder anomalies, gastrointestinal anomalies, as well as several skeletal anomalies that may manifest only later in pregnancy [7, 10, 12, 14, 25, 2932].


Table 13.2
First-trimester detection rates for congenital anomalies









































































































































































































































































Author

Country

Year

N

Approach

Detected anomalies N (%)

Additional fetuses with anomalies detected >14 weeks (including second- and third-trimester scans and postnatally) N (%)

First-trimester detection rate (%)

Rottem et al. [1]

Israel

1989

141

TV

3 (2.12)

0

100

Cullen et al. [27]

USA

1990

622

TV

33 (5.31)

NA

NA

Rottem and Bronshtein

Israel

1990

1652

TV

40 (2.42)

4 (0.24)

90.9

Achiron and Tadmor [3]

Israel

1991

800

TA and. TV

8 (1.00)a

6 (0.75)

57.1

Bonilla-Musolles

Spain

1994

834

TV

27 (3.24)

3 (0.36)

90

Yagel et al. [29]

Israel

1995

536

TV

42 (7.8)

13 (2.4)

76.4

D’Ottavio et al. [31]

Italy

1995

4078

TV

54 (1.3)

34 (0.83)

61.4

Hernadi and Torocsik [30]

Hungary

1997

3991

TA and TV

20 (0.41)

29 (0.73)

40.8

Economides et al. [63]

England

1998

1632

TA + TV

11 (0.67)

6 (0.37)

64.7

Whitlow et al. [64]

England

1999

6634

TA + TV

37 (0.56)

55 (0.83)

40.2

Guariglia and Rosatti [10]

Italy

2000

3478

TV

33 (0.95)

31 (0.89)

51.6

Carvalho et al. [65]

Brazil

2002

2853

TA + TV

29 (1.02)

101 (3.54)

22.3

den Hollander et al. [66]

Netherlands

2002

101

TA + TV

9 (9)

2 (2)

81.8

Drysdale et al. [67]

England

2002

984

TA

5 (0.51)

25 (2.54)

16.7

Taipale et al. [68]

Norway

2004

4513

TV

6 (0.13)

27 (0.59)

18.2

Chen et al. [69]

Hong Kong

2004

1609

TA + TV

14 (0.87)

12 (74.6)

53.8

Becker and Wegner [14]

Germany

2006

3094

TA + TV

72 (2.36)

14 (0.45)

83.7

Saltvedt et al. [70]

Sweden

2006

18,053

TA

74 (0.41)

297 (1.64)

20

Cedergren et al. [71]

Sweden

2006

2708

TA

13 (0.48)

19 (0.70)

40.6

Dane et al. [72]

Turkey

2007

1290

TA + TV

17 (1.32)

7 (0.54)

70.8

Chen et al. [69]

Hong Kong

2008

3949

TA + TV

30 (0.76)

33 (0.84)

47.6

Oztekin et al. [73]

Turkey

2009

1085

TA and TV

14 (1.29)

7 (0.65)

66.6

Ebrashy et al. [7]

Egypt

2010

2876

TA + TV

21 (0.73)

10 (0.35)

67.7

Syngelaki et al. [28]

England

2011

44,859

TA + TV

213 (0.48)

275 (0.61)

43.6

Iliescu et al. [11]

Romania and Greece

2013

5472

TA + TV

67 (1.22)

98 (1.05)

41.1

Bromley et al. [12]

USA

2014

9962

TA + TV

50 (0.50)

130 (1.30)

27.7

Goldstein et al. [21]

Israel

2014

4467

TA + TV

33 (0.74)

28 (1.04)b

54.1


TA + TV, transabdominal ultrasonography, followed by transvaginal ultrasonography if adequate views could not be obtained transabdominally; TA and TV, transabdominal followed by transvaginal ultrasonography in all cases; TV, only transvaginal ultrasonography

a4/8 anomalies detected only by transvaginal ultrasonography

bAscertainment available for only 60 % of the scanned pregnancies


What Does 3D Ultrasound Add?


3DUS adds the possibility to obtain multiple planes of an anatomical structure from a 3D volume dataset. The elevation plane, in particular, which is perpendicular to the direction of the sound beam, is impossible to obtain using conventional 2DUS. This capability can be particularly advantageous during the first trimester, when manipulation of the vaginal probe is restricted and, therefore, the obtainable planes of section are limited [33]. Another potential benefit, provided that it can be proved beyond doubt that offline analysis of volume datasets has at least the same level of accuracy as real-time analysis of 2DUS images, is that embryonic exposure to ultrasound can be reduced, since volume acquisition takes only a few seconds and image processing and analysis can be performed offline [34].

Sonoembryology is the term that describes a detailed assessment of the live embryo in vivo by high-resolution transvaginal ultrasonography [33, 35, 36]. Initial publications on sonoembryology relied on images obtained by 2DUS. Since the original work describing the use of a specially designed high-resolution 3D transvaginal probe for reconstruction of small embryonic structures by Blaas et al. [37] in 1995, several investigators have reported on the use 3DUS for volumetric measurement [38, 39], assessment of normal embryonic development and early fetal anatomy [34, 4046], as well as early prenatal diagnosis of congenital anomalies [42, 4755].

The best studied organ has been the embryonic brain, with initial studies focusing on volumetry and anatomy of cerebral brain vesicles [37, 38, 56]. Today, exquisite 3D images of the ventricular system can be obtained using commercially available equipment and inversion mode technology (Fig. 13.1), as reported by Kim et al. [42], who obtained 3DUS volumes of the embryonic and early fetal brain by transvaginal ultrasonography in 46 patients examined between 6 and 13 menstrual weeks. Inversion mode was used to reconstruct the early ventricular system. Appropriate reconstructions were possible only for volumes acquired between 7 and 12 weeks. Based on the experience with that work, the authors correctly diagnosed one case of alobar holoprosencephaly at 10 6/7 weeks and one case of early ventriculomegaly at 12 4/7 weeks.

A328333_1_En_13_Fig1_HTML.jpg


Fig. 13.1
3D rendering of the early cerebral ventricles using inversion mode. P pontine flexure, D diencephalon (future third ventricle), M mesencephalon (future sylvian aqueduct), IR isthmus rhombencephali, RH rhombencephalic cavity

As it is natural to occur with any emerging technologies, several case reports and series have illustrated how 3DUS helped with specific diagnoses, mainly during the embryonic period [4851, 5760]. Among the most interesting are the early detection of a case of spina bifida at 9 weeks with exquisite detail of the defect demonstrated by 3D surface rendered images of the embryonic torso (Fig. 13.2) [49, 5860], confident diagnoses of cyclopia [50] and proboscis [50, 51] by 3D multiplanar reconstruction at 9 2/7 weeks [50] and 10 6/7 weeks [51] in association with alobar holoprosencephaly, digital casts of the abnormal ventricular system in cases of holoprosencephaly as early as 9 2/7 weeks, conjoined twins at 9 [55] and 10 weeks [57], prune-belly syndrome [58], iniencephaly [45] and frontonasal malformation [61] at 11 weeks, and severe scoliosis associated with omphalocele [58] and encephalocele [45] at 12 weeks.
Jun 4, 2017 | Posted by in ULTRASONOGRAPHY | Comments Off on Three-Dimensional Ultrasound: A Role in Early Pregnancy?

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