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 cant 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
11. Uterine or Mullerian Anomalies According to American
Fertility Societys 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.
12. 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
13. 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
14. 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
15. Uterus didelphys. A composite of a multiplanar display (AC)
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.
16. 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.
17. 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.
18. 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
.
19. 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.
20. 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.
21. 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
22. 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
23. 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.
24. 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.
25. T-shaped uterus. Multiplanar and rendered views were
acquired during 3D sonohysterography.
26. Intracavitary lesions
27. Endometrial polyp
28. Composite findings of a subseptate uterus with multiple
enodmetrial polyps
29. 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.
30. 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
31. Uterine synechiae
32. 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).
33. 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).
34. Cystic adenomyoma. A composite of a multiplanar display of
the uterus (AC) 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.
35. Locating Early Gestational Sac
36. Ovaries and adenxae
37. Multicystic ovarian mass
38. 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.
39. 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
40. Fallopian tubes. 3D HyCoSy (Hysterosalpingo Contrast
Sonography)
41. 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
42. 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).
43. 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 .
44. Endometrial Receptivity Endometrial receptivity is defined
as a temporary unique sequence of factors that make the endometrium
receptive to the embryonic implantation.
45. 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.
47. 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
48. 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.
49. VFI (vascularization flow index) : is the average colour
value of all colour and grey voxels and describes both: the
vascularization and the blood flow.