(1)
Gynecologic Imagine Service, Department of Obstetrics, Gynecology and Reproduction, Institut Universitari Dexeus, Barcelona, Spain
Betlem Graupera graduated in Medicine and Surgery in 1999, obtaining a PhD degree in 2012 from the Universitat Autònoma de Barcelona. She is currently working in the Department of Obstetrics, Gynecology and Reproduction of Institut Universitari Dexeus in Barcelona.
She is a member of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG). Her main research is in ultrasonographic diagnostics in the field of gynecology.
Maria Àngela Pascual graduated in Medicine and Surgery in 1981, obtaining a PhD degree in 1993 from the Universitat Autònoma de Barcelona. She is currently working in the Department of Obstetrics, Gynecology and Reproduction of Institut Universitari Dexeus in Barcelona.
She is a full member of the Spanish Society of Fertility (SEF), since 1989. She is also a member of the American Institute of Ultrasound in Medicine (AIUM) since 1990 and a senior member since 2000. In addition, she is a member of the Ultrasound Section Spanish Society of Gynecology and Obstetrics (SEGO) since 1991 and the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) since 1991. Her main research is in ultrasonographic diagnostics in the field of gynecology.
6.1 Introduction
Congenital uterine anomalies, also known as Müllerian duct anomalies, result from isolated or complex alterations during any step of the embryogenic development of the uterus.
The prevalence of these malformations varies between 5.5 % in the general population and around 24.5 % in patients with history of infertility or miscarriage [6].
The most commonly used classification for uterine anomalies has been that of the American Fertility Society (AFS) [32] (Fig. 6.1). Recently, the European Society of Human Reproduction and Embryology and the European Society for Gynaecological Endoscopy (ESHRE-ESGE) has established a new consensus on the classification of congenital malformations of the female genital tract [14] (Fig. 6.2).
Women with congenital uterine anomalies can be asymptomatic [31] or can present both obstetric and gynecological symptoms, including pelvic pain and presence of mass, due to obstruction of the outflow of menstrual residue with hematocolpos and hematometra, as well as infertility and miscarriage [27]. Spontaneous abortion, preterm delivery, malpresentation at delivery, low birth weight, and perinatal mortality rates are higher compared to pregnant women without congenital uterine abnormalities [34]. Uterine malformations may be associated with other congenital anomalies, which are, frequently, anomalies of the urinary tract [16].
Several imaging techniques are used to diagnose uterine anomalies. Transvaginal ultrasound (2DUS), which provides information on the uterine anatomy mainly in the sagittal and transversal planes of the uterus, has been used to screen for congenital uterine anomalies [17].
Since 3DUS is a noninvasive, reproducible, and low-cost technique that simultaneously provides information about both the external contour and the uterine cavity, it’s the technique of choice in the study of uterine anomalies [2, 7, 17, 28]. Three-dimensional ultrasound has the ability to provide an exceptionally clear coronal view of the uterus and its anatomical details [26]. With 3DUS, unlike 2DUS, the differential diagnosis of congenital uterine malformations and their severity can be made. The reproductive prognosis and therapeutic strategy can be determined.
A good level of accuracy in the diagnosis of uterine anomalies with 3DUS has been previously demonstrated in relation to hysterosalpingography [17], hysterosalpingography and laparoscopy [28], hysteroscopy [12, 18, 19], hysteroscopy and laparoscopy [5, 9, 11, 25, 36], and finally with MRI [2, 5, 12, 13]. Moreover, 3DUS showed good interobserver agreement in the diagnosis of uterine anomalies [29].
6.2 How We Do It
6.2.1 Three-Dimensional Ultrasound
6.2.1.1 Data Acquisition
The acquisition of volume data is performed in the sagittal plane of the uterus, going from the cervix to the fundus and ensuring that the endometrial lining is entirely displayed and shown as a horizontal structure perpendicular to the ultrasonic beam. Once the 3D volume was acquired, a multiplanar mode view was obtained. The uterine data are displayed in three orthogonal planes: A, the midsagittal plane of the uterus; B, the axial uterine plane; and C, the coronal plane (Fig. 6.3).
Fig. 6.3
Multiplanar display shows the midsagittal view (a), the transverse plane (b), and coronal plane (c) of the uterus
The angle between the ultrasound beam and the endometrial lining must be 90°. If the uterus is too wide to be scanned in its entirety in a sagittal view, the 3D volume is obtained from a transverse plane so that both uterine horns can be visualized (Fig. 6.4). If possible, volume acquisition is performed in the luteal phase of the menstrual cycle to improve diagnostic accuracy [5].
Fig. 6.4
Multiplanar view obtained from a transverse plane (Window A) in a uterine malformation with a large transverse diameter corresponding to a wide partial septate uterus
To evaluate the cervix, isolated cervical volumes are acquired with the transvaginal probe in the vagina. This is performed in a sagittal plane and also with an angle of 90° between the ultrasound beam and the cervix.
The ultrasound evaluation of the vagina is performed with a transvaginal probe in a transperineal acquisition. Acquisition volume data is done in a sagittal plane of the pelvic floor, showing, from anterior to posterior, the pubic symphysis, urethra and bladder, vagina, rectum, and anal canal (Fig. 6.5).
Fig. 6.5
Transperineal three-dimensional ultrasound image in a woman with a duplicate vagina (Fig. 6.34). Transperineal acquisition is done in a sagittal plane of the pelvic floor (Window A), showing, from anterior to posterior, the pubic symphysis (PS), urethra (U) and bladder (B), vagina (V), rectum (R), and anal canal (AC). The rendered image clearly shows the duplicate vagina
Uterine, cervical, and vaginal volumes are acquired with a machine setting of maximum quality and with a maximum sweep angle.
In all cases, it is first necessary to firmly hold the probe during volume acquisition and second to request that the patient remains as still as possible, including minimum respiratory movement.
6.2.1.2 Rendering Volumes
Rotations and translations can be performed through a selected point where the three perpendicular planes intersect. Any changes in any planes are processed in real time and are instantly updated, simultaneously displaying the two remaining orthogonal planes and the rendered image (Fig. 6.6). There are different ways to achieve this goal depending on where the direction of the region of interest is placed. The volume box is adjusted on the uterine cavity with green line aligned over it, adapted to the curve of the uterine cavity.
Fig. 6.6
Rendering mode showing the three perpendicular planes and the rendered image. The rendering box was adjusted adapting the green line to the curved line of the uterine cavity, to obtain a rendered image of the uterus
Analysis of uterine morphology is done on the rendered image of the coronal plane with the interstitial portion of both fallopian tubes serving as reference points (Fig. 6.7). Uterine morphology was described using the criteria detailed in Table 6.1.
Fig. 6.7
Three-dimensional ultrasound rendered image demonstrates the coronal plane, showing the normal external fundal contour and the interstitial portion of both fallopian tubes as reference points (arrows)
Table 6.1
Ultrasound criteria for the classification of congenital uterine anomalies
Classification | Fundal contour | External contour |
|---|---|---|
AFS [32] | ||
Normal | Straight or convex [29] Internal indentation <10 mm [20] | Uniformly convex or with indentation <10 mm [29] |
Class I: hypoplasia/agenesis | ||
Class II: unicornuate | Single well-formed uterine cavity with a single interstitial portion of the fallopian tube and concave fundal contour [29] Abnormal lenticular shape of the endometrial cavity [33] | Asymmetric ellipsoidal shape (“banana shaped”) [33] |
(a) Communicating | Communication between the uterine cavity with the cavity of rudimentary horn | Fundal indentation >10 mm dividing the two cornua [29] |
(b) Noncommunicating | No communication between the uterine cavity with the cavity of rudimentary horn | Fundal indentation >10 mm dividing the two cornua [29] |
(c) No cavity | No cavity in rudimentary horn | Fundal indentation >10 mm dividing the two cornua [29] |
(d) No horn | No rudimentary horn | |
Class III: didelphys | Endometrial cavities are uniformly separate, with no evidence of communication [33] | Two separate divergent uterine horns with a large fundal cleft [33] |
Class IV: bicornuate | Two well-formed uterine cornua [29] Transverse section through the distal part of the uterus: double endometrial/myometrial echo. Transverse section through the middle part of the uterus: double endometrial stripe [20] Distance between the interostial line and the uterine fundus: >15 mm [20] | Sagittal planes: the length of the corpus measured to each of the horns is >10 mm greater than the length of the corpus taken through the fundal midline [20] |
(a) Complete | External cleft up to cervix | |
(b) Partial | External cleft above the cervix | |
Class V: septate | Transverse section through the distal part of the uterus: double endometrial stripe without doubling of the myometrium. Transverse section through the middle part of the uterus: double endometrial stripe [20] Distance between the interostial line and the uterine fundus: >15 mm [20] | Sagittal planes: the length of the corpus measured to each of the horns is ≤10 mm more than the length of the corpus taken through the fundal midline [20] |
(a) Complete | Distance between the intercornual line and the apex of the fundal extern contour <10 mm [20] | |
(b) Partial | Proximal part of the uterine cavity partially divided by a septum [17] Presence of septum, which does not extend to the cervix, with central point of the septum at an acute angle (<90°) [29] | Distance between the intercornual line and the apex of the fundal extern contour <10 mm [20] |
Class VI: arcuate | Transverse section through the distal part of the uterus: double endometrial stripe without doubling of the myometrium. Transverse section through the middle part of the uterus: single endometrial stripe [20] Rounded appearance of the fundal portion of the uterine cavity [17] Concave fundal indentation with central point of indentation at obtuse angle (>90°) [29] Distance between the interostial line and the uterine fundus: >10 and <15 mm [20] | Sagittal planes: the length of the corpus measured to each of the horns is ≤10 mm more than the length of the corpus taken through the fundal midline [20] Uniformly convex or with indentation <10 mm [29] Distance between the intercornual line and the apex of the fundal extern contour <10 mm [20] |
Class VII: T shaped | T configuration of the uterine cavity with extreme narrowing of the vertical limb [33] | |
ESHRE-ESGE [14] | ||
Class U0: normal uterus | Straight or curved interostial line but with an internal indentation <50 % of the UWTa [14] | Normal outline or external cleft <50 % of the UWTa [14] |
Class U1: dysmorphic uterus | Normal uterine outline or external cleft <50 % of the UWTa [14] | |
(a) T shaped | Narrow uterine cavity (2/3, uterine corpus; 1/3, cervix) [14] | |
(b) Infantilis | Narrow uterine cavity (1/3, uterine corpus; 2/3, cervix) [14] | |
(c) Others | Minor deformities of the uterine cavity with an inner indentation at the fundal midline <50 % of the UWTa [14] | |
Class U2: septate uterus | Internal indentation at the fundal midline >50 % of the UWTa [14] | External contour straight or with indentation <50 % of the UWTa [14] |
(a) Partial | Internal indentation above the level of the internal cervical os [14] | |
(b) Complete | Presence of a septum fully dividing the uterine cavity up to the level of the internal cervical os [14] | |
Class U3: bicorporeal uterus | External indentation at the fundal midline >50 % of the UWTa [14] | |
(a) Partial | External fundal indentation partly dividing the uterine corpus above the level of the cervix [14] | |
(b) Complete | External fundal indentation completely dividing the uterine cavity up to the level of the cervix [14] | |
(c) Bicorporeal septate | The width of the midline fundal indentation exceeds by 50 % the UWTa [14] | |
Class U4: hemi-uterus | Existence of a fully developed functional uterine hemicavity with or without rudimentary (functional) cavity [14] | Unilateral uterine development; the contralateral part could be either incompletely formed or absent [14] |
(a) With a rudimentary cavity | With communicating or noncommunicating functional contralateral horn of the cavity [14] | |
(b) Without rudimentary cavity | Without functional contralateral horn of the cavity [14] | |
Class U5: aplastic uterus | Absence of any fully or unilaterally developed uterine cavity [14] | Bilateral or unilateral rudimentary horns [14] |
(a) With rudimentary cavity | Cavity remnant/s present [14] | |
(b) Without rudimentary cavity | Cavity remnants absent [14] | |
There are different rendering modes. In general, surface-rendered images allow for good visualization of the uterine cavity and the myometrium in order to evaluate the relationship between the uterine cavity and the external fundal contour. It is necessary to adjust luminosity and contrast curves for rendered images, as well as for threshold and transparency.
Three-dimensional ultrasound also facilitates volume calculation of anatomical structures, like the uterine cavity, using different tools. This is useful to determine the best treatment to apply to patients, if necessary [26] (Fig. 6.8).
Fig. 6.8
Three-dimensional VOCAL™ ultrasound image in a woman with a complete bicorporeal uterus. This tool allows the volume of the uterine cavity to be calculated so that the best one may be chosen in the event of assisted reproduction treatment. In this case, the volume of the left uterine cavity (white arrow) is greater than the right one (yellow arrow)
Tomographic ultrasound imaging (TUI) allows correct analysis of the vagina, providing sequential planes in any orthogonal plane with multiplanar view [3]. This tool is also useful to analyze the cervix (Fig. 6.9).
Fig. 6.9
Tomographic ultrasound imaging (TUI) tool performed in a woman with an incomplete cervical septum, seen in Fig. 6.31. Eight parallel 2 mm separate planes of the cervix were obtained. The -3, -2, and -1 slices (white arrows) show the septum dividing the cervical canal. The green point slice and slices 1–4 show the single cervix (yellow arrows)
6.3 Normal Uterus
Two-dimensional ultrasound shows a uterine morphology classically known as “pear shaped” in the sagittal view. Cross sections show a rather flattened round morphology. The endometrium is a bright line in a central position on sagittal images (Fig. 6.10), and it widens toward the uterine horns in cranial cross sections (Fig. 6.11).
Fig. 6.10
Two-dimensional ultrasound showing a sagittal view of the normal uterus with a uterine morphology classically known as “pear shaped.” The endometrium is a bright curved line in a central position
Fig. 6.11
Two-dimensional ultrasound cross section of a normal uterus shows a rather flattened round morphology. The endometrium is a bright line toward the uterine horns in cephalic sections
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