UPDATE IN ULTRASONOGRAPHY IN GYNAECOLOGY
By HUSSEIN HOSSAMALDIN KAMEL SALEM 2008
INTRODUCTION In fact, several modalities have been described in recent years that may signify a revolution almost as great as the advent of real-time, spectral Doppler and color imaging. These are three-dimensional ultrasound, ultrasound contrast media (UCM), and harmonic imaging. All three have already brought improvements in diagnostic capabilities.
Improved Images via Computer Technology One
of the most dramatic improvements in the ongoing development of ultrasound imaging has been the application of technology srcinally developed for use in computers. With the wedding of computer technology and diagnostic ultrasound, a computerized image formation process provided blackand-white images with superior resolution and clarity.
Digital Beam formation The development of a digital beamformer in the mid-1980s and the subsequent migration to a digital platform by ultrasound manufacturers substantially raised the level of performance industry-wide. This new technology allowed for more sensitive, consistent, and accurate acquisition of sonographic data, providing for higherresolution images.
Doppler Imaging The introduction of duplex pulsedDoppler in the mid-1970s enabled 2D gray scale imaging to be used in the placement of the ultrasound beam for Doppler signal acquisition. Doppler ultrasound analysis has been used in gynecology primarily to determine blood flow in ovarian tumors with neoplastic characteristics.
Doppler ultrasound has the potential to study patterns of pelvic walls and hence identify functional changes. The availability of pulsed Doppler instruments has made it possible to sample signals at a chosen depth and thus to direct flow in any selected deep pelvic vessel.
Color Flow Doppler (CFD)
In color flow Doppler color encoded flow information is superimposed on a real time grey scale ultrasound image. Shades of red are used for flow towards the transducer and shades of blue are used for flow away from the transducer. With color flow Doppler, information about the presence or the absence of the blood flow, its direction can be obtained.
Disadvantages of CFD The
need of the pulsed wave Doppler as the CFD gives no quantitative information.
It
is an angle dependant.
There
may be reduced frame rate or degradation of resolution or both due to the extra time used in scanning each line.
The internal iliac artery (red) and Vein (blue) are distinguished by color Doppler according to the brightness of the color and pulsation not b y the color itself
Color Mapping of Doppler Amplitude (Doppler power or Doppler Energy)
m
Advantages OF Power Doppler Increased
sensitivity for detecting low velocity circulatory systems as in tumor vessels.
Virtual
independence of the angle of insonation.
May
allow better delineation of flow in vascular channels. Absent of Nyquist defect (Aliasing effect).
mDisadvantages
of
Power
Doppler
Does
not provide information on the direction of flow. Depth
dependent so the greater the depth of
the vessel, the less available amplitude flow information..
Color Doppler amplitude image of the uterine vessel obtained by TVS
Harmonic Imaging Harmonic
Imaging (THI) increased spatial and contrast resolution and more effectively suppressed artifacts compared with conventional B-mode imaging not only in obese patients, but also in many other applications.
Contrast--enhanced Contrast enhanced ultrasound (CEUS) Contrast-enhanced ultrasound (CEUS) allows an adequate delineation of vessels in relation to the pure intra-vascular characteristics of those agents, reinforced by the real-time assessment of the enhancement after contrast injection. This may be important when dealing with tiny vessels beyond the resolution of grayscale ultrasound, color imaging, or power Doppler.
Following an intravenous (IV) injection, the ultrasound contrast agent (UCA) reaches the organ of interest (such as the ovary) and time intensity curves can be created to evaluate the degree, speed (slope) and duration of pixel enhancement produced by the UCA.
Generally,
tumors demonstrate steeper rises and slower washouts secondary to angiogenesis.
Furthermore, benign and malignant processes can be differentiated since in malignancy, absorption should be faster and the UCA should remain in tissues longer and should be excreted faster.
Malignant tumors have a larger number of vessels and higher pixel density when examined with color Doppler. This has already been shown in breast, liver and prostate cancers and undoubtedly will be in the future in other fields such as ovarian cancer screening
3D
Imaging
The first 3D scanner was produced in 1974, but it was not computerized and proved a disappointment.
Computerized modeling of ultrasound images began in the 1980s and the result of that research, combined with 3D scanning technology, ultimately led to the development of improved 3D imaging.
In gynecology, 3-D offers undeniable advantages, planes not otherwise accessible are available, e.g. the coronal plane in uterine imaging.
Three D images be reconstructed data obtained withcan a single sweep of thefrom US beam across the involved organ. As a result, the exact relationship between anatomic structures is accurately recorded.
Three-dimensional US allows unrestricted access to an infinite number of viewing planes.
Three-dimensional US allow comparison of two full data sets over time, thereby improving accuracy of evaluation.
With 3D US, different viewing algorithms allow the data to be displayed with a variety of techniques, including surface rendering, volume rendering, and multiplanar reformatting.
Three-dimensional US has been shown to provide a more accurate and repeatable method of evaluating anatomic structures and disease entities.
CLINICAL APPLICATIONS OF ULTRASOUND IN GYNAECOLOGY
Normal Uterine U/S Finding
An anteverted uterus in early Proliferative phase (TVS).
A retroverted uterus in secretory phase (TVS).
(TAS) of a normally antete-verted uterus in LS. Transverse section shows both ovaries and uterus. (b) Urinary bladder (u) Uterus (L) left ovary The thick arrow shows fluid in (POD).
Normal uterus using 3D showing the coronal view .
Contrast
Imaging
Uterine
artery
and
vein
visualized
transvaginal color Doppler sonography. sonography
by
Doppler flow of the uterine artery There is a small amount of end diastolic flow in the uterine artery during the proliferative phase. EDF disappears at the day of ovulation. Increased RI 3 days after LH surge has been observed.
Color Flow of the ovarian artery shows a low velocity and the resistance varies greatly according to menstrual cycle.
Uterine artery Doppler assessment . A) shows a w aveform typical of normal vessel resistance. B) demonstrates a waveform from a vessel with elevated resistance.
Color Doppler showing subsub-e endometrial blood flow
Congenital Uterine Anomalies 3D Ultrasound is more accurate than 2D Ultrasound for diagnosing arcuate, subseptated, septated and bicornuate uteri, but not for didelphys. It is very useful to determine the dimensions of uterine septum, which may provide very useful information to surgeons during hysteroscopy.
Subseptate Uterus
Co mplete Septate
The Endometrium
In the absence of significant endometrial pathology, the entire thickness of the endometrium appears uniform. The thickness and appearance vary with the timing of the cycle; a range of (5±14 mm) is considered to be normal in women of reproductive age. As the proliferative phase progresses, the endometrium not only thickenss but also becomes less echogenic; however, the myometrial± endometrial interface and the interface between the opposing two layers of endometrium becomes more echogenic and the classic three-stripes endometrial echo is observed. Toward the end of the proliferative phase, the entire endometrial complex becomes increasingly echogenic
Drugs
and the endometriu
Oral
contraceptive : the endometrium typically is thin, echogenic and regular in appearance.
RU
486 ± mifepristone : the Endometrium is of highly disorganized.
Danazol thin.
:
the endometrium is atrophic and
Cy
proterone acetate: cause the endometrium to become thick and echogenic.
Tamoxifen: causes proliferation of the endometrium results in hyperplasia, metaplasia and can lead to carcinoma.
Hormone
replacement therapy (HRT): With continuous combined therapy, the endometrium should be uniformly thin (< 4 mm) and similar in appearance to that of a postmenopausal woman who is not taking HRT
A large cystic hyperehoic endometrial polyp (arrow) secondary to tamoxifen therapy .
Sono--hysterography Sono hysterography Indications Abnormal uterine bleeding in both premenopausal and postmenopausal women. Infertility and habitual abortion.
Congenital abnormalities of the uterine cavity. The uterine cavity, especially with regard to uterine myomas, polyps, and synechiae. Abnormalities detected on endovaginal sonography, including focal or diffuse endometrial or intracavitary abnormalities. A suboptimally imaged endometrium by endovaginal sonography.
Endometrial polyps An endometrial polyp usually appears as a well-defined, homogeneous, polypoid lesion that is isoechoic to the endometrium with preservation of the endometrialmyometrial interface. Atypical polyps have cystic components, multiplicity, a broad base, and hypoechogenicity or heterogeneity.
An endometrial polyp (P) disrupting the midline eccho (thick arrow) and the endometrium (thin arrow) around the polyp.
Sonohysterogram of a patient with typical appearance of an endometrial polyp. Note the narrow base of attachment to the posterior endometrial surface (arrows).
Blood flow to an endometrial Polyp by power Doppler.
Uterine polyp (by 3 D sonohystrography).
Endometrial hyperplasia Endometrial hyperplasia usually appears as diffuse thickening of the echogenic endometrial stripe without focal abnormality, but occasionally focal hyperplasia can be seen.
Cystic endometrial hyperplasia. a clear hypoechoic line demarcates the myometrial boarder (arrow).
Endometrial hyperplasia seen By sonohystrography
Endometrial cancer Endometrial cancer is typically a diffuse process, but early cases can appear as a polypoid mass.
ENDOMETRIAL CANCER
INTRA UTERINE SYNECHIEA Adhesions usually appear as mobile, thin, echogenic bands that bridge a normally distensible endometrial cavity, but occasionally thick, broad based bands or complete obliteration of the endometrial cavity is seen.
Thick endometrial adhesions as seen by sonohystrosalpigography
Uterine thin adhesions as seen by three D sonohystrography
ULTRASONOGRAPHY AND FIBROID Fibroids can be diagnosed as well-defined hypoechoic areas arising from within the myometrial layer, causing attenuation of the ultrasound beam and distal shadowing.
Sonohystrography in fibroid The major advantage of sonohysterography over other imaging modalities is that it can accurately depict the percentage of the fibroid that projects into the endometrial cavity. This feature is important because only those fibroids in which at least 50% of the mass projects into the endometrial cavity may be removed hysteroscopically.
Submucous fibroid Submucosal fibroids are usually broadbased, hypoechoic, well-efined, solid masses with shadowing and an overlying layer of echogenic endometrium that distorts the endometrial-myometrial interface. Atypical fibroids are pedunculated or have a multilobulated surface. In addition, as opposed to polyps, submucosal fibroids often distort the interface between the endometrium and myometrium and show acoustic attenuation
A large submucus fibroid (F) distorting the uterine cavity (arrows). The fibroid is hypoechoic in relation to the surrounding myometrium.
Typical submucosal fibroid. The percentage of protrusion of the fibroid into the endometrial cavity is equal to 50%.
Sonohystrogram with submucus fibroid The percentage of the protrusion into the endometrial cavity is less than 50%.
3-D sonography in fibroid
Three-dimensional volume ultrasound is superior to two-dimensional views in identifying the degree of protrusion of a submucous fibroid into the cavity, as well as the amount of myometrium remaining outside which of the submucous fibroid, all information is needed before hysteroscopic resection of these lesions can be undertaken.
One
can also measure the volume of such a fibroid or polyp or even the volume of the entire endometrium, quickly and easily using a 3D volume set
3D of a submucosal fibroid showing that the echogenicity of the endometrium acts as a contrast medium.
Doppler blood flow in fibroid
Diastolic flow in patients with fibroid uterus is usually present in the myometrial vessels and increased relative to the seen in the uterine arteries. Uterine artery flow velocity in the normal uterus has a mean RI of 0.84. In women with fibroids a slight decrease in the mean RI to 0.74 was observed. The mean RI of myometrial blood flow in these patients was 0.54.
Three D Power Doppler could assess fibroid vascularization, before and after uterine embolization.
Contrast-enhanced Contrastenhanced sonography in uterine fibroid Injection of SonoVue could provide a very precise description of the uterine vascularization more easily than with angiography and cheaper than MRI. After contrast injection, macroand microcirculation of the myoma enhancement first appeared, followed by the normal myometrial and finally within the endometrium. Enhancement patterns vary markedly among the patients, from an absence of enhancement for the whole tumor, to a complete and rapid enhancement after injection. Wash-out was typically complete after 3 minutes, giving a black hole corresponding to the whole lesion. This wash-out helps us to identify some tiny fibroids that are not visible on conventional sonography.
Arterial enhancement within uterine fibroid after SonoVue injection demonstrating a quite globular and intense enhancement higher than from normal myometrium (b), followed by a marked wash out (c).
Contrast-enhanced Contrastenhanced sonography in uterine fibroid Contrast enhanced Ultrasound can also be proposed to detect the persistence of vessels within a treated myoma with higher confidence, as it was reported that this precedes the late recurrence confirmed by an increased size of the myomas. This will be a more sensitive method than color Doppler Ultrasound for an assessment of induced vascularity changes.
Adenomyosis
Sonographic criteria for adenomyosis Globular
shaped uterus. Myometrial cysts (2-6 mm in diameter). Mottled inhomogeneous myometrium. Indistinct Indistinct
borders to a myometrial mass. endometrial stripe. Hyperechoic myometrial nodules. Asymmetric thickening of the anterior or posterior uterine wall. Minimal mass effect on the endometrium or serosa.
A large adenomyoma (a) seen at the fundus of the uterus casting an acoustic shadow (arrow). I t is slightly distorting the cavity (broken arrow)
Cystic spaces (arrows) associated with adenomyosis.
The echogenic nodules within the anterior myometrium (arrows) suggest adenomyosis.
Endometrial Cancer Endometrial cancer on ultrasound appears as diffuse thickening of the endometrium similar to hyperplasia, or as an inhomogeneous focal mass. Usingthe a double-wall of 5 mm or greater, sensitivity thickness for detecting endometrial cancer is 96% regardless of whether a woman is receiving hormone replacement therapy. A thin endometrium of 5 mm or less had a high negative predictive value, and this finding would support the diagnosis of atrophy.
Sono-hystrography in endometrial cancer
Lack of distentability of the uterine cavity during sonohystrosalpigography is the most consistent finding in women with endometrial cancer.
At sonohysterography, early cases can appear as a polypoid mass.
An intact subendometrium is suggestive of localized disease, whereas extension of heterogeneity and increased echogenicity in the myometrium is seen with advanced invasive endometrial carcinoma
Doppler and endometrial cancer Transvaginal power Doppler blood flow mapping can be useful to differentiate benign from malignant endometrial pathology in women presenting with postmenopausal bleeding and thickened endometrium at baseline sonography.
3--D D
sonography in endometrial cancer Three D US improved the diagnostic accuracy of ultrasound to determine myometrial and cervical invasion in endometrial carcinoma.
Endometrial cancer. Sonohysterogram demonstrates diffuse, irregular, inhomogeneous thickening of the anterior endometrium (between arrowheads)
Ultrasonography and cervical carcinoma
Local assessment of angiogenesis using enhanced US agent will be of value to follow local changes under chemotherapy or radiotherapy and to better schedule surgery.
The staging approach using three D Ultrasound is new, and the relatively good results yielded by using sub-optimal equipment in the hands of a non gynecologist indicate a potential future for the technique.
Three D power Doppler ultrasound provides a useful tool to investigate intratumor vascularization and volume of cervical cancer.
Alterations of 3D USG derived vascular indices were found in patients with cervical cancer and some vascular indices proved to be associated with tumor size.
Typical strong and homogeneous enhancement from cervical cancer (a) after SonoVue injection (b)
The ovaries The ovaries are usually located in the ovarian fossa, inferior to the pelvic vessels on the lateral pelvic wall. However, they are mobile structures and can be found in the pouch of Douglas or above the uterine fundus; they can be located by following the broad ligament laterally.
The left ovary seen medial to the left iliac vessel. A few follicles (f) are seen in the cortex. The ovarian stroma (s) which occupies the central section of the ovary appears moderately echoic.
Ova Ov arian rian blood flow during the menstrual cycle
During the proliferative phase; the RI is approximately 0.54 until ovulation approach. A decline begins 2 days before ovulation and reaches a nadir at ovulation.
Immediately after follicular rupture, there is another dramatic increase in the velocity of blood of blood flow to the early corpus luteum.
The RI remains at that level for 4-5 days and then gradually climbs to 0.5 which is still lower than that seen during the proliferative phase.
Intraovarian blood flow during the proliferative phase of the normal menstrual cycle
Pulsed w ave Doppler waveform analysis typical for corpus luteum neovascularization.
The characteristic blood flow of a corpus luteum is halolike and of high velocity and low resistance.
Ultrasound in detecting
early
ovarian carcinoma
Among µhigh-risk¶ women (women with a family history of ovarian cancer or a personal history of breast cancer) the sensitivity for detection of Stage was 25% while the sensitivity forI disease low-risk women was 67 %.
This less-than-ideal sensitivity is not unexpected, because in many Stage I ovarian cancers, the ovaries are neither enlarged nor morphologically abnormal.
Ultrasound in detecting
early
ovarian carcinoma
The use of color or Power Doppler imaging has not been shown to add significantly to the diagnosis of early-stage disease.
3-D volume acquisition and 3-D Power Doppler may help in the early identification of abnormal vascularity and architectural changes within the ovary. Excrescences not seen by 2-D technology may be observed. While 3-D Power Doppler provides a new tool for measuring the quality of ovarian vascularity, its clinical value for the early detection of ovarian carcinoma has yet to be determined. The efficiency of 3-D Power Doppler imaging in identifying Stage I ovarian cancer has yet to be determined.
The low annual prevalence of ovarian cancer within the general population, the large number of women who must therefore be screened to identify a single ovarian cancer, and the poor sensitivity of the test for Stage I disease make routine use of ultrasound for detection of ovarian cancer impractical.
Vascular projection in a cyst
Surface rendering of a papillary in a cyst
Update In Ultrasonography In Infertility Ovarian
Reserve: There is no doubt that antral follicle counts are an important predictor of 'ovarian reserve.
The antral follicular count is the number of 'selectable follicles' measuring 2±5 mm on day three of the menstrual cycle.
Three-dimensional sonography as an adjunct to conventional markers of ovarian reserve when they examined ovarian volume and the number of 'selectable folliclesµ.
Monitoring Of Treatment Cycles
Serial monitoring of follicular development is useful in both natural and stimulated ovarian cycles. In natural cycles, several small follicles may be seen in the early follicular phase. However, the dominant follicle is selected between day 5 and day 7 and other follicles will gradually decrease as this follicle develops.
Follicular rupture occurs between 18 mm and 28 mm during natural cycles, with an average growth rate of 1.2 mm to 2.0 mm per day. It is essential that serial monitoring is carried out to determine normal growth of the Graafian follicle and to determine follicular rupture.
Normal ovary with the presence of a preovulatory dominant follicle
It is important that ultrasound examination is performed between day 10 and day 15 in a cycle preceding IVF, for the following reasons: (1) to check that the uterine cavity is normal. (2) The presence of hydrosalpinges should be noted. (3) The presence of ovarian cysts can affect follicular development and may warrant treatment prior to IVF. In many cases, if the cyst is below 3 cm in size, aspiration of the cyst, if performed prior to stimulation, will aid the ovarian response. (4) When ovaries are enlarged to greater than 3.5 cm, the risk of hyperstimulation syndrome is increased. 5) The examination is used to check-the distribution of the follicles in the ovary.
The appearance of an ovary demonstrating multiple follicular development characteristic of ovarian hyperstimulation syndrome
Frozen embryo transfere
In most centers frozen embryos are transferred during a natural cycle.
Embryos are usually transferred 2 or 3 days after ovulation. If urine or blood monitoring is not performed to monitor the LH surge, then ultrasound scans must be performed on a daily basis once the lead follicle reaches a mean follicular diameter of 16 mm.
POLYCYSTIC OVARY
In cases of polycystic ovaries, the ovaries may contain ten or more cystic structures distributed peripherally around a central core of stroma. Such ovaries have been termed polycystic and are usually associated with menstrual irregularity, raised luteinizing hormone (LH) levels, hirsutism, anovulation and an increased incidence of miscarriage.
Three D ultrasound has been used to measure ovarian and stromal volumes, providing information that is not available from twodimensional (2D) ultrasound
Polycystic ovary showing the multiple small cysts (c) a rranged peripherally and the typical increased volume of echogenic stroma (s)
Polycystic
ovaries are defined according to the following criteria (Adamjs criteria):
10 or more cysts of between 2 and 8 mm arranged peripherally
ovarian > 8 cm3 (implying increasedvolume ovarian of stroma).
Multicystic ovaries are distinguished from polycystic ovaries in that the cysts are spread throughout the ovary rather than peripherally.
A typical flow velocity diagram at the stroma shows higher velocity in polycystic ovary syndrome .
Three-dimensional sonography facilitates objective assessment of the ovarian stroma, through measurement of its mean grey signal intensity .
Ovarian blood flow in PCO is increased and associated with significantly higher three-dimensional indices of vascularity than ovaries with a normal appearance .
Ultrasound for predicting endometrial receptivity in ARTs Uterine Biophysical profile (UPP)
Tubal patency assessment Under normal circumstances, the fallopian tubes are not visible with ultrasound imaging unless there is fluid within the pouch of Douglas. However, when the tubes are damaged by infection they can become enlarged and form fluidfilled hydrosalpinges. These are generally readily visible during scanning because the fluid within the tubal lumen provides a negative echo contrast.
A hydrosalpinx containing anechoic fluid and incomplete septation (s)
The µbeads-on-a-string¶ sign (arrows) considered as additional evidence of the presence of hydrosalpinx.
A hydrosalpinx showing a low level echoes within the distended fetal tube together with incomplete septations.
The typical colour Doppler energy findings hydrosalpinx
of
Hysterosalpingo-contrast
sonography (HyCoSy) involves the instillation of a positive contrast agent, such as Echovist® (Schering AG, Germany), into the uterine cavity during scanning. Flow of the contrast medium through the tubes and into the peritoneal cavity can be readily seen. Using either pulsed or color Doppler, improved sensitivity for contrast flow can be obtained. HyCoSy can provide similar information about tubal patency.
Threehree-di dimensional color power Doppler HyCoSy demonstrating free peritoneal spill of contrast dye.
Following surface rendering of the threethree-di dimensional image.
Ectopic pregnancy The introduction of beta hCG testing and transvaginal ultrasound has changed our approach to the patient suspected of an ectopic pregnancy. Important advantage of the most currently used trans-vaginal transducers is the ability to perform simultaneous color and spectral Doppler studies, allowing easy identification of the ectopic peritrophoblastic flow. Therefore, color Doppler may be applied whenever a finding is suggestive of ectopic pregnancy.
Ectopic pregnancy in Lt. tube
Ectopic gestational sac in the left adnexal region surrounded by a ring of fine near by vessels.
False positive finding by US in cases of Ectopic pregnancy
Corpus luteum.
Endometriosis.
Pelvic inflammatory disease. Other adnexal masses or tumors.
Ovarian
cancer.
False negative causes of US doppler detection of Ectopic pregnancy
Very early ectopic pregnancy.
Avascular ectopic gestation.
Technical difficulties. Patient non compliance.
Further progress in diagnostic procedures is made with introduction of 3D ultrasound. Transvaginal 3D ultrasound enables the clinician to thus perceive true spatial relations and easilythe distinguish the srcin of an adnexal mass, while 3D power Doppler allows detailed analysis of the vascularization.
Rt. interstitial ectopic pregnancy by 3-D trasnvaginal sonography
Ultrasound and Pelvic floor assessment Modern ultrasound probes provide a large view angle encompassing both the anterior and the posterior compartments of the pelvic floor. The possibility to image not only the pelvic organs but also muscle and fascial components of the pelvis offer a possible advantage over standard Xray imaging and place U/S in competition with MRI.
Three D pelvic floor ultrasound has been used for the evaluation of the urethra and its structures, for imaging of the more inferior aspects of the levator ani complex (pubococcygeus and puborectalis), for the visualization of paravaginal supports, as well as for prolapse and implant imaging. One of the major advantage of 3D US is the possibility to acquire information on a patient ³volume´, to store it and to have it available for further analysis and review along any plane.
The effect of a Valsalva manoeuvre on the levator hiatus (left, at rest; right, on Valsalva) in a young nullip arous woman without significant pelvic organ descent. The dimensions of the levator hiatus are measured in the sagittal (1) and coronal (2) planes
The levator hiatus at rest (left) and on Valsalva (right) in a young woman with significant pelvic organ descent. On Valsalva the levator is situated partly outside the acquisition volume
Interventional ultrasonography
Intrauterine device (IUD). Ultrasonography and embryo-transfer. Tubal catheterization. Ultrasound puncture of adnexal cysts.
F ocused US. assisted intrapelvic La paroscopysonography. Myometrial biopsy. US Guided ovarian biopsy. Fetal reduction. Transcervical metroplasty. Salpingocentesis.
(IUD) in place
IUD's in the coronal plane in the cervix
Ultrasonography in embryo transfer
Ultrasound-guided embryo transfer has been around since 1985 and has become almost universal in the past three years. The advantages of ultrasound-guided embryo transfers include the facilitation of embryo transfer as well as the physician¶s ability to visualize catheter and embryo placement.
Three-dimensional ultrasound enables the physician¶s to visualize the uterine cavity as a whole.
The maximal implantation potential (MIP)
The uterine cavity resembles an inverted triangle and the fallopian tubes open into the cavity, one in each of the upper regions of the triangle. The MIP is the intersection of these two imaginary lines, one srcinating in each fallopian tube, within the inverted triangle. In natural pregnancies, implantations usually occurs in the anterior or posterior segment of the uterus close to its path line, where the endometrium is the thickest and has the greatest blood flow.
By using the MIP point, placement of the embryos occurs where nature intended.
Because of individual anatomic differences, the MIP point can be individually tailored. Further advances in 3D ultrasonography as well as the introduction of 4D sonography have enabled us to visualize the transfer catheter in real time as it moves towards its target, the MIP point .
A) 3D ultrasound image. The maximal mplantation potential (MIP) point is marked with an asterisk. (B) Anatomic diagram demonstrating the MIP point.
Embryo flash is confirmed on 3D ultrasound after transfer in area of maximal implantation potential.
Focused ultrasound generates heat, ablating tissue only at the focal point. The effect is similar to a magnifying glass used to focus the sun¶s energy on a single point.
Longitudinal section of Fallopian tube. A C catheter; I isthmus; M mucosal layer; ML layer
ampulla; muscle
Tubal pregnancy at 7 weeks gestation. (a) Transvaginal scan (TVS); BL bladder; GS gestational sac; Ut uterus. (b) Laparoscopy-assisted intrapelvic sonography (LAIPS); AM amniotic membrane; C catheter; GS gestational sac. Arrows show enlarged tube.
SALPINGOCENTESIS Cases of tubal ectopic pregnancies to be considered for transvaginally guided puncture must meet several criteria: the ectopic gestational sac must contain a viable fetus with a menstrual age of less than 8 weeks¶ gestation, and the tubal diameter should not exceed 2.5²3 cm.
Tubal ectopic pregnancy during salpigocentesis
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