3D and 4D ultrasound provide several advantages over traditional 2D ultrasound for assessing female pelvic anatomy and pathology. Multiplanar views allow for more accurate diagnosis of uterine anomalies by visualizing the coronal and true midline planes. Intracavitary lesions can be precisely localized. Ovarian volumes and antral follicle counts are more accurately determined. Endometrial receptivity markers like vascular indices are measurable. Doppler of uterine arteries provides additional information on receptivity. Overall, 3D/4D ultrasound improves evaluation of female pelvic structures and fertility-related conditions.

1. Dr. Omneya Nagy Elmakhzangy
Special Fetal Care Unit
Ain Shams University
Member of EFMF

2. 3D and 4D scanning
 It is the process of creating a 3D visual presentation of
parameters of interest.
 The main principle behind this is "planar geometric
projection" i.e a 2D image to represent the 3D data the
third dimension impression is acquired through online
rotation of the image along X , Y and Z axis.

3. Voxel and Pixel

4.  Imaging practitioners routinely use cross-
sectional planar ultrasonographic
information to develop a three-dimensional
(3D) mental concept of anatomy.
 With three-dimensional ultrasonography
(3DUS), any desired plane through a pelvic
organ can be obtained, regardless of the
orientation of the sound beam during
acquisition.

5.  With 3D or volume ultrasonography, a
volume (rather than a slice) of
ultrasonographic data is acquired and
stored. The stored data can be reformatted
and analyzed in numerous ways; navigation
through the saved volume can show
innumerable arbitrary planes. In the
multiplanar display, 3 perpendicular planes
are displayed simultaneously.
 This will further expand the ability to show
complex anatomic relationships

6. Normal uterus. A multiplanar display shows the axial view (A), the midsagittal plane (B), and
the true midcoronal plane (C). Depiction of the true midsagittal and midcoronal planes is
achieved by correlation between the 3 planes. The midcoronal view (C) clearly shows the
normal external fundal contour of the uterus and the normal triangular shape of the
endometrial cavity.

7. Clinical Applications

8. Uterus

9. Normal uterus
 Logic question : why can’t we usually obtain a coronal
section in a 2D scan?
 Answer: you have to options to scan the uterus either
transabdominaly and in this case the sides of the bony
pelvis will prevent scanning through pelvic side walls ,
transvaginally and this is limited by the physical
limitation in moving the probe within the boundaries
of the vagina .

10.  The normal uterus, as seen in the coronal plane, has a flat
or slight upwardly convex fundal contour.
 The endometrium is normally approximately triangular,
the top of which is flat or minimally concave toward the
lumen .
 The echogenicity of the endometrium varies during the
cycle but is generally more echogenic than the
myometrium.
 The normal endometrium should have a homogeneous
echo texture, and the endometrial-myometrial junction
should be distinct.
 The cervical canal is seen as a tubular echogenic structure
extending inferiorly from the lower endometrial cavity. The
contour of the cervix is well shown in the coronal view

13. Uterine or Mullerian Anomalies
 According to American Fertility Society’s scheme,
there are 7 classes of anomalies:
 class 1 : segmental agenesis or hypoplasia;
 class 2 : unicornuate uterus.
 class 3: uterus didelphys;
 class 4: bicornuate uterus;
 class 5: septate uterus;
 class 6: arcuate uterus
 class 7: diethylstilbestrol-related anomalies.

14. Class 1
 The unicornuate uterus is essentially half a uterus
didelphys with a single “hemiuterus” deviated to the
right or left of the midline, showing only a single
cornual angle.
 The diagnosis of unicornuate uterus is very difficult to
confirm with 2DUS because the findings are subtle.
The nulliparous unicornuate uterus is somewhat
smaller than normal and deviated from the midline.
The multiplanar capability of 3DUS permits confident
demonstration that there is only 1 cornual angle

15. Unicornuate uterus. A multiplanar display of the left unicornuate
uterus is shown. This diagnosis is difficult to establish with 2DUS
because the uterus may appear grossly normal or slightly laterally
deviated. With 3DUS, the diagnosis is confidently made because
the coronal plane (C) shows clearly that there is only a single
cornual angle

16. Class 2
 The uterus didelphys consists of 2 distinct and
separate uterocervical cavities. The 2 fundi are widely
separated and may not be completely imaged on any
single planar image. The cervices are adjacent to each
other, but the cervical canals are distinct

17. Uterus didelphys. A composite of a multiplanar display (A–C) of the
uterus and a coronal image of the cervix (D) from another volume is
shown. The axial plane (A) shows 2 widely separated hemiuteri, typical of
this malformation. The sagittal plane (B) is between the 2 hemiuteri and
therefore shows very little. The coronal plane (C) shows the widely
separated fundal regions (arrows); the lower uterine segments and the
cervical canals are closely apposed.

18. Class 3
 The bicornuate uterus has a midsagittal cleft or
indentation in the external contour of the fundus of at
least 1 cm in depth . In addition, the uterine cavity is
divided by a septum that extends caudally for a
variable extent. The cervix of the bicornuate uterus
may be single or double.

19. Bicornuate unicollis uterus. This coronal view shows the deep
(>1-cm) midline sagittal groove (arrows), which characterizes
this type of uterine anomaly. In this case, a single cervical
canal is shown; however, a bicornuate uterus may have 2
cervical canals.

20. Class 4
 The septate uterus, the most common uterine
anomaly, usually has a normal external fundal contour
but may have a shallow fundal indentation measuring
no more than 1 cm in depth .

21. Septate uterus. A composite of a multiplanar display (A, axial; B, sagittal; C,
coronal) and a rendered image of the endometrial cavity, extracted from the
uterus (D), is shown. Note that the septum is relatively long and thin and
extends down to the level of the cervix (thin arrow). The external contour of
the uterine fundus is shown in the coronal plane (C) as smooth, indicating a
septate and not a bicornuate uterus.

22. Class 5
 The cavity of the septate uterus is divided partially or
completely by a septum of variable thickness. If the
septum does not extend down to the uterine isthmus
(the level of the internal cervical os), the malformation
is termed a subseptate uterus.

23. Subseptate uterus. Three-dimensional multiplanar sonohysterography
shows a normal external uterine contour. The coronal plane is ideal for
precise definition of this uterine malformation. This is a subseptate uterus
because the septum extends caudally to the lower uterine segment but not
to the internal os. The addition of fluid helps outline the extent of the
septum and exclude other intracavitary abnormities

24. Class 6
 The arcuate uterus has a normal external fundal contour
but an inner fundal contour abnormality in which the
fundal myometrium is convex toward the uterine lumen.
This convex myometrium should not exceed a height of 1
cm when measured from the cornual angle .
 The actual prevalence of the arcuate uterus is unknown
because the subtle abnormality is easily missed without
visualization of the coronal plane. The clinical importance
of this mild abnormality is uncertain, although this lesion
is generally thought of as less problematic than the septate
uterus

25. The coronal view, obtainable only with 3DUS, can directly visualize
the endometrial and fundal contours, ruling out the diagnosis of a
subseptate uterus and confirming a positive diagnosis of an arcuate
uterus.

26. Class 7
 The diethylstilbestrol-related uterus has a hypoplastic
cavity with variable deformity of the shape of the
uterine cavity .The external uterine contour is normal,
but the uterine cavity is smaller than normal and has
been described as T shaped. Constriction bands occur
in the upper uterus, resulting in bulbous cornual
regions and a deformed uterine body. The lower
uterine segment may be widened but more often
shows severe stenosis.

27. T-shaped uterus. Multiplanar and rendered views were
acquired during 3D sonohysterography.

28. Intracavitary lesions

29. Endometrial polyp

30. Composite findings of a subseptate uterus with multiple enodmetrial polyps

31. Endometrial calcification and a small submucpus myoma, This
technique of manipulating the multiplanar display and
correlating the findings in all 3 planes is used to confirm the
location of a lesion, to show that a finding is real rather than
artifactual, or to show that a true midsagittal or midcoronal plane
has been obtained.

32. Intrauterine contraceptive device .This coronal view, obtainable only with 3DUS,
assists in precisely localizing the device within the uterine cavity. The IUD is shown
to be slightly caudal to the fundal myometrium, which is convex toward the lumen
in this subtle uterine anomaly. However, the IUD is entirely within the endometrial
cavity without evidence of myometrial penetration

33. Uterine synechiae

35. Myometrium
 Uterine myomas can be assessed by 3DUS. The
multiplanar display, especially the coronal view, allows
precise localization of a myoma with respect to the
endometrial cavity. Precise localization of uterine
myomas assists in determining the surgical approach
(hysteroscopic resection or abdominal myomectomy).

36. Intracavitary myoma and endometrial polyp. Three-dimensional
multiplanar sonohysterography shows a round mass, which is isoechoic
with the myometrium and almost completely surrounded by fluid. This
intracavitary myoma (m) is deemed amenable to hysteroscopic
resection. In addition, there is a more echogenic, smaller endoluminal
mass representing a polyp (p).

40. Cystic adenomyoma. A composite of a multiplanar display of the uterus (A–C) and another oblique coronal plane
through the uterus (D) is shown. There is a cystic mass in the right side of the uterus containing uniform low-level
echoes and surrounded by myometrium. The initial differential diagnosis included a left unicornuate uterus with an
atretic rudimentary right horn. Three-dimensional ultrasonography was useful in showing the exact midcoronal
plane through the endometrial cavity (C). The cavity is shown to be triangular in shape with 2 cornua (arrows),
excluding a unicornuate uterus. A, Axial view through the uterus showing the cystic mass on the right. B, Sagittal
view of the uterus at the level of the endometrium. C, View through the midcoronal plane of the endometrial
cavity. D, Oblique coronal view through the long axis of the cystic mass, which best shows the normal fundal
contour of the uterus and the rim of myometrium surrounding the mass.

41. Locating Early Gestational Sac

48. Ovaries and adenxae

49. Multicystic ovarian mass

50.  For assessing the patency of the fallopian tubes, x-
ray HSG and laparoscopy are still the most widely
used methods. Recently, ultrasonography with
fluid as a contrast agent (ie, sonohysterography)
has been used in the diagnosis of tubal patency or
blockage.
 On 3DUS, the entire tube can be evaluated
because a volume of data rather than a single slice
is saved and reviewed later from any arbitrary
plane.

51.  This method appears to have advantages over the
conventional hysterosalpingo-contrast ultrasonographic
technique, especially in terms of visualization of a spill
from the distal end of the tube, which is achieved twice as
often with the 3D technique.
 The mean duration of the imaging procedure is shorter
with 3D , but the operator time, which includes
postprocedure analysis of the stored information, is similar.
 A considerably lower volume of contrast medium is used
for 3D PDI in comparison with that used for conventional
2D hysterosalpingo-contrast ultrasonography

53. Fallopian tubes. 3D HyCoSy
(Hysterosalpingo Contrast Sonography)

54. Basal Ovarian Volume and AFC in
infertility cases
 Three D ultrasound is more accurate in determining
ovarian volume using the Virtual Organ computer-
aided Analysis (VOCAL, GE Kretz) technique .
 This technique employs a rotational method which
involves the manual delineation of the ovarian volume
throughout several planes as the data set is rotated
through 180 degrees in a consecutive series of rotations
( angle dependant on number of planes chosen could
range from 6 ◦ to 30◦ ) , until a calculated volume is
generated

56. Antral follicular Count and
folliculometry
 Number of follicles at the early follicular phase has
been reported to be a good test for prediction of
ovarian response (Kwee 2007, Jayaprakasan 2008) .
 All follicles < 10mm are measured using 2D
ultrasound in the longitudinal and transverse planes,
however 3D techniques are now available for
automatic calculation (SonoAVC) (Raine-Fenning 2008).

58. Folliculometry
 A new automated ultrasound software technique has
recently been developed which relies on volume
calculation using 3-dimensional VOCAL technique
and on colour coding of each follicle (SonoAVC, GE )
(Raine Fenning 2008).
 A 3D volume is obtained of the stimulated ovary, and
using the software will give mean diameter and volume
of the hypo echoic areas within the ovary representing
the follicles, it will then colour code each follicle
differently allowing studying each one separately .

60. Endometrial Receptivity
 Endometrial receptivity is defined as a temporary
unique sequence of factors that make the
endometrium receptive to the embryonic
implantation.

61. Optimal conditions of implantation could be:-
 Endometrium > 7 mm,
 Endometrial volume > 2 ml
 Hypoechogenic endometrium with 3 well
delinated layers,
 Uterine PI < 3,
 Presence of sub-endometrial vascular flow.
 High VI,FI&VFI in endometrial & sub-
endometrial zone.

64. • uterine artery Doppler
(PI=3.16).
uterine artery Doppler (PI=1.15).

67. • 1- VI (Vascularization index):
Vascularization index is the ratio of the
number of color voxels (volumetric pixel) to
the total number of voxels in the sampled
tissue, thus it represents the percentage of
vascularized tissue

68. • 2- FI (flow index) : Flow index is the
average colour value of all colour voxels and
it describes the mean velocity of flow in the
sampled tissue.

69. • VFI (vascularization flow index) : is the
average colour value of all colour and grey
voxels and describes both: the
vascularization and the blood flow.