Historic Development Using Transabdominal Technique
The ease of discerning small details of the intrauterine contents in the presence of amniotic or spontaneous uterine fluid is well known. Early efforts to supply artificial fluid in the nonpregnant woman using transabdominal scanning were effective but cumbersome. In 1984, Richman et al reported the instillation of 70% dextran through a rigid uterine cannula during transabdominal sonographic observation before standard HSG in 34 patients.1 Their interest in the uterine cavity was limited to the observation that tubal obstruction produced sustained expansion of the uterine cavity. The observation of the accumulation of peritoneal fluid in 25 of 34 patients correctly identified at least unilateral tubal patency with an accuracy of 97%.
Randolph et al described the results of a similar approach using sterile saline as the medium to predict surgical findings in anesthetized women about to undergo laparoscopy or hysteroscopy in 1986.2 They accurately described 53 of 54 uteri, and the pathologies described included unicornuate uteri, septae, polyps, and intracavitary or submucous myomata. Only a unicornuate uterus with a noncommunicating horn was mistaken for a small normal uterus, providing 98% sensitivity and 100% specificity regarding intrauterine abnormalities. They also found that identification of fluid accumulation in the posterior cul-de-sac reliably indicated at least unilateral patency with a sensitivity of 100% and specificity of 91%. Tube-specific accuracy, however, was poor. They required 100 cc of fluid for visualization of the fimbria of the tube in the cul-de-sac, and they noted that isolated accumulation of fluid above the fundus indicated adhesions or a mass obliterating the cul-de-sac. Easily identified hydrosalpinges were observed to form with distal obstruction.
Other small series supported the use of abdominal ultrasound and the observation of accumulation of cul-de-sac fluid as a simple screening technique for at least unilateral tubal patency, but made little comment on the uterine cavity.1,3
In Belgium, however, van Roessel et al scanned 30 uteri distended with dilute dextran 70 during hysteroscopy and compared the ultrasonic and endoscopic diagnoses.4 Despite procedural artifacts, only a 2-mm polyp was missed; 8 normal cavities were accurately assessed as normal. Three myomata (only 1 intracavitary), 3 septae, 2 cases of synechiae, and 6 polypoid lesions were predicted. Unusual "ragged" endometrium was noted in 7: 1 was due to cancer, 3 were due to hyperplasia, and 3 were normal proliferative endometrium. Ultrasound with contrast allowed them to identify both polypoid lesions and thick, irregular endometrium. Two intrauterine devices (IUDs) were located precisely, including one embedded in the myometrium that could not be seen by the hysteroscopist. Three uterine septae were diagnosed, and resection was monitored successfully by ultrasound rather than laparoscopy in 2 of the cases. Imaging of another cancer failed due to the inability to maintain uterine distention. Abnormalities were identified in 10 of 21 apparently normal uteri by the use of cavitary distention, and precision of diagnosis was enhanced in 5 of 9 uteri that were abnormal with conventional ultrasound.
Limitations of Transvaginal Sonography
The widespread use of high-frequency transvaginal sonography beginning in the late 1980s brought exciting detail to images of pelvic organs. Cyclic endometrial changes and concepts of normal ranges of thickness had already been described in transabdominal studies.5,6, and 7 Extreme distortion and pathologic thickening due to cancer or hyperplasia had also been identified, as had uterine anomalies and thick synechiae.8,9, and 10 The detailed magnified images of endometrium and ovaries that are routinely obtainable with transvaginal scanning allow accurate diagnosis of both hormonal and structural causes of abnormal bleeding,11,12 amenorrhea,13,14, and 15 and infertility.16
Even with high-frequency transducers, the cause of an abnormal endometrial image is not always apparent. Fedele et al found transvaginal ultrasound comparable to hysteroscopy in detecting submucous myomata, but had difficulty distinguishing between myomata and polyps.17 Typically hyperechoic, endometrial polyps are best seen during the proliferative phase. However, they may be indistinguishable against a background of secretory endometrium, which is typically echogenic. Relatively hypoechoic myomata are well imaged when outlined by secretory endometrium, but can obscure the endometrium entirely by acoustic shadowing. Thick synechiae and cavitary anomalies are best imaged in the periovulatory or secretory endometrium. Intrauterine synechiae may be highlighted by sequestered hematometra, but often the endometrial deficiency is subtle. Distinction between an anomaly, such as a T-shaped uterus, and synechiae can be difficult.
Dodson evaluated 45 women with abnormal bleeding and imaged structural abnormalities in one-third of them.12 He used the ovarian and endometrial appearance to confirm functional ovulatory abnormalities in the rest. Three ovulatory patients with appropriately thick hyperechoic endometrium had intermenstrual bleeding that eluded diagnosis, suggesting they might have had polyps obscured by secretory endometrium.
Narayan and Goswamy recommended transvaginal ultrasound for screening in infertility patients, having diagnosed abnormalities correctly in 182 of 193 women (94%).16 After weekly evaluation of 200 patients throughout their cycles followed by hysteroscopy, they found that periovulatory multilayered endometrium best revealed intracavitary lesions and the uterotubal junctions. Fourteen patients, however, had nonspecific irregularities on ultrasound that required diagnostic hysteroscopy for definition. On hysteroscopy 2 had normal cavities, 4 had polyps, 2 had synechiae, 1 had a septum, and 3 had endometritis. Furthermore, only 44 of 51 submucosal myomata seen by ultrasound were truly intracavitary. Seventy-one of seventy-six synechiae were seen by ultrasound, as were 43 of 46 polyps, and 5 of 6 septae. There was a 5.5% false-positive rate. These are the cases that will typically benefit from saline infusion for better definition before either excluding or undertaking therapeutic surgery.
The atrophy of the endometrium in postmenopausal women makes evaluation of their endometrium straightforward in the absence of distorting leiomyomas or adenomyosis. Measurement of endometrial thickness is an efficient way to exclude endometrial neoplasia. A meta-analysis of endometrial thickness in postmenopausal women by Smith-Bindman et al included 35 studies and over 3500 women. Use of the 5-mm threshold for endometrial thickness resulted in a 96% sensitivity for detection of endometrial cancer.18 Symmetrical endometrium of 4 to 5 mm decreases the a priori risk of endometrial cancer in bleeding postmenopausal women by 90%, from 10% to 1% in untreated women and from 1% to 0.1% in women with hormone replacement therapy (HRT).18,19
A single report of 3 cancers that were not detected by 7-MHz vaginal ultrasound in 3 uteri with sonographic double-wall measurements of 3.3 and 2 mm, respectively, did not include gross measurement, sonographic images, or histologic description of the cancers.20 Hence, one must suspect an error in technique or inadequately imaged endometrium due to distortion or uterine position, rather than invisible endometrial cancers in atrophic endometrium. The endometrial cavity is a three-dimensional (3D) structure. Pathologic changes may be focal. A single "frozen" long-axis view may miss the abnormality. Care must be taken to recreate the 3D anatomy from multiple views. Efficient acquisition of this complete cavitary assessment is an advantage of 3D sonography.
A scanty or atrophic biopsy specimen from a thickened endometrium may be due to inadequate sampling of focal areas. This may be due to inadequate sampling of focal areas of hyperplasia, for instance, using a 2-mm piston-type suction device21; to compression of a fibrous polyp in an atrophic endometrium22; to distortion by myomata; or to the appearance of myometrial changes surrounding an otherwise normal cavity as has been seen in selected patients on tamoxifen therapy.23
Hence, conventional transvaginal ultrasound is quite sensitive, but is not as specific as direct examination of the endometrial cavity with hysteroscopy, the gold standard for the detection of endometrial abnormality.24 SHG aids in the sonographic identification, localization, and description of intracavitary lesions.
Investigators around the world have independently developed methods to enhance transvaginal images of the cavity with intrauterine fluid, usually sterile saline, instilled through a fine catheter during scanning. In 1988, Deichert et al reported their pioneering observations in the German literature on the effects of fluid in the uterine cavity, but then turned to the study of positive contrast agents for tubal patency.25,26
In 1991, Mitri et al in South Africa, using an 8 French Foley catheter in the cervix, demonstrated that SHG was more informative than conventional HSG.27 Fifty normal cavities were demonstrated by both methods, but 9 women had otherwise undetectable extracavitary myomata visible by ultrasound. All 4 submucous myomata were seen by both methods. Four bifid uterine cavities were tentatively diagnosed as septate by HSG, and were definitively diagnosed as harboring 3 septae and 1 intramural myoma by ultrasound. The 2 methods agreed in one case of intrauterine synechiae. One HSG failed due to intravasation of contrast, whereas SHG and laparoscopy demonstrated a normal uterus and bilateral hydrosalpinges.
Bonilla-Musoles et al in Spain found SHG to have a sensitivity of 96%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 97%.28 Twenty-two normal women, 16 women with menometrorrhagia, and 16 infertile women were studied. Two cases of focal hyperplasia were missed, and 1 normal uterus was thought to contain hyperplasia, in a total of 74 patients. There were 2 failures due to pain and stenosis, respectively. Submucosal myomata, hyperplasia, synechiae, and a septum were correctly diagnosed, and they considered SHG equal to hysteroscopy except for the detection of tiny focal hyperplasia. They suggested it be used for preoperative and posttreatment evaluation and monitoring.
Syrop and Sahakian diagnosed, measured, and correctly located polyps in 14 infertility patients with abnormal images noted during sonographic screening before in vitro fertilization, using a rigid Rubin cannula and Ringer lactate or human tubal fluid.29
Parsons and Lense reported 100% detection of intracavitary abnormalities in 39 patients with abnormal bleeding and abnormal endometrial images, which was confirmed by hysteroscopy or hysterectomy.30 Polyps, myomata, synechiae, and irregular thickening that proved to be hyperplasia or cancer were accurately identified. Two small, raised areas were seen that proved to be polypoid islands of normal proliferative endometrium on hysteroscopic biopsy. Cancer could not be distinguished from hyperplasia, because both produced irregularly thickened endometrial surfaces. Twenty infertile patients judged to have normal cavities by SHG demonstrated normal cavities with hysteroscopy, HSG, or both.
Goldstein described accurate results of SHG in 21 postmenstrual women with abnormal bleeding. He found 11 focal lesions and confirmed them with hysteroscopy: 8 polyps and 3 submucous myomata.31 Nine of the other ten patients had early proliferative changes on biopsy, dilation and curettage (D&C), or hysteroscopy. Hyperplasia was confirmed in the remaining patient with an inappropriately but symmetrically thick endometrium, and atrophy was confirmed in the rest. Sonohysterography was also used to demonstrate normal cavities in 5 patients undergoing sonographic monitoring during tamoxifen treatment.23 Despite what appeared to be thickened, honeycombed endometrium, curettage and hysteroscopy yielded scant tissue in one. Infusion confirmed that the abnormality appeared to be myometrial with symmetrical unstimulated endometrium confirmed by biopsy in every case.
Farquar et al performed a systematic review of transvaginal sonography, sonohysterography, and hysteroscopy for investigation of abnormal uterine bleeding.32 The pooled likelihood ratio for diagnosis of submucous fibroids by SHG was 29.7. This was similar to the likelihood ratio for hysteroscopy.
Dueholm et al evaluated 189 women with transvaginal sonography and sonohysterography, comparing the sonographic findings to that found at hysteroscopy or hysterectomy.33 The sensitivity for the diagnosis of polyps in submucous myomas in women with abnormal bleeding was 99%, with a specificity of 72%. The authors concluded that sonohysterography was a sensitive tool, superior to unenhanced transvaginal sonography for the evaluation of abnormal uterine bleeding. Similarly, Krampl et al compared transvaginal sonography, SHG, and operative hysteroscopy in the evaluation of abnormal uterine bleeding in 100 consecutive patients.34 They found that the detection rate of focal intrauterine pathology using SHG was significantly higher than using transvaginal sonography alone. Visual examination by hysteroscopy yielded no additional information to the detection of focal lesions than that obtained at SHG. Even in women with abnormal uterine bleeding with endometrial thickness of less than 5 mm, up to 20% will have focal intracavitary lesions seen by SHG but not visualized by unenhanced transvaginal sonography.35
Indications for Sonohysterography
The most common indication for SHG is to determine the cause of abnormal uterine bleeding. The main contraindication for SHG is the presence of a known or suspected viable intrauterine pregnancy. In most cases conventional sonography will provide a rapid diagnosis when performed in the periovulatory period: Dysfunctional bleeding due to disorganized hormone production is confirmed by the lack of evidence of impending ovulation and lack of a periovulatory multilayer endometrium. When the endometrium is asymmetrical, unexpectedly thickened, or poorly imaged, SHG will clarify the anatomy. Although clots should be evacuated to avoid confusion, SHG often provides an interpretable image despite uterine bleeding.
Although the diagnosis of endometrial masses requires histologic examination, SHG allows one to make the distinction between global and focal processes, an important consideration before office biopsy or D&C. Small, flexible Pipelle-type biopsy instruments are very popular with physicians and patients despite their tendency to sample less than 5% of the endometrial cavity.21 When a global process is identified, this device is adequate. When there is a focal lesion or asymmetry, direct visualization of the endometrial cavity with resection of masses via hysteroscopy guidance is indicated. An inexplicably abnormal endometrial image (by computed tomography, magnetic resonance imaging [MRI], HSG, or ultrasound) due to thickness or distortion, particularly in an asymptomatic individual, can be conveniently assessed to plan further intervention only where it is warranted.
Secondary amenorrhea or hypomenorrhea is infrequently caused by endometrial synechiae due to trauma or infection in a poorly estrogenized endometrium. These are easily demonstrated by SHG, enabling hysteroscopic resection if pregnancy is desired or observation if it is not.
Evaluation of the endometrial cavity is a standard part of the workup for infertility, usually by HSG. The use of hysteroscopy has increased as it has become clear that there is a high incidence of intracavitary abnormalities in infertile patients.36,37 HSG, however, produces a high rate of false-positive uterine findings, reported as 30% by Valle, prompting many unnecessary procedures.38 Sonographic screening before undertaking in vitro fertilization is increasingly practiced. With the use of SHG to further define suspected abnormalities, hysteroscopy can be reserved for those requiring surgical repair or directed biopsy, rather than as an expensive diagnostic tool. Anomalies, synechiae, polyps, submucosal myomata, and hyperplasia due to prolonged anovulation have all been demonstrated in reported series and in our patients using sonographic contrast, often after years of infertility treatment. As widespread experience in the use of sonographic contrast for tubal patency increases, unnecessary exposure of the gonads to radiation may become limited to special cases.
The diagnosis of müllerian anomalies is aided by sonohysterography. Alborzi et al studied 20 patients with a history of recurrent pregnancy loss with the HSG diagnosis of a septate or bicornuate uterus.39 Surgical confirmation of the diagnosis was available in 10 cases. SHG was able to differentiate between septate and bicornuate uteri in all cases. The authors concluded that sonohysterography alone was sufficiently accurate to proceed directly to hysteroscopic septum resection without performing a laparoscopic examination. Valenzano et al examined 54 patients with infertility or recurrent miscarriage, and with a clinically or sonographically suspected abnormal uterus.40 All subjects had an HSG and SHG, and in those with suspected anomalies, hysteroscopy or laparoscopy was performed. SHG was able to detect all anomalies accurately. The authors utilized defined criteria for diagnosis of uterine malformations by SHG as defined in Table 38-1.
Table 38-1SONOGRAPHIC CRITERIA FOR DIAGNOSIS OF UTERINE MALFORMATIONS ||Download (.pdf) Table 38-1 SONOGRAPHIC CRITERIA FOR DIAGNOSIS OF UTERINE MALFORMATIONS
|Type of Uterine Malformation ||Transvaginal Sonographic Criteria ||Sonohysterographic Criteria |
|Septate uterus ||Convex, flat, or indented fundal contour. The mass dividing the endometrial canal is complete, extending into the endocervical canal ||Convex, flat, or indented fundal contour. Complete division of the endometrial canals by an echogenic mass, with echotexture similar to that of myometrium |
|Sub-septate uterus ||Convex, flat, or indented fundal contour. The mass dividing the endometrial canal is partial; the mass reaches the uterus corpus and/or the isthmus ||Convex, flat, or indented fundal contour. Partial division of the endometrial canals by an echogenic mass, with echotexture similar to that of myometrium |
|Bicornuate uterus ||Divergent uterine horns, single cervix, large fundal cleft (>1 cm) ||Divergent uterine horns, single cervix, large fundal cleft (>1 cm) |
|Didelphic ||Separate divergent uterine horns, large fundal cleft, cervical duplication ||Cervical duplication on physical examination. Complete separation of the uterine horns infusing saline solution in both cervical canals |
|Intrauterine synechiae ||Partial or complete division of the endometrial canal compatible with fibrous tissue ||Failure to fully distend the cavity. Mobile, thin, echogenic bands that bridge the endometrial cavity, hypoechoic relative to myometrium, compatible with fibrous tissue |
|Arcuate ||Normal fundal contour, smooth indentation of the fundal endometrial canal. No division of uterine horns ||Normal fundal contour. Minimal indentation of the fundal canal. No uterine duplication |
The location and measurement of intracavitary versus submucosal myomata should be mapped preoperatively before undertaking hysteroscopic resection. As described by Narayan and Goswamy, a truly submucosal myoma may appear to distort the cavity on conventional sonography, but it may not be evident through the hysteroscope.16 The depth of the intramural component of a submucosal myoma can also be appreciated preoperatively. Occasionally, synechiae are difficult to distinguish intraoperatively, especially in the cornua and along the walls. The postoperative effects of all hysteroscopic procedures, including endometrial ablation, are evaluable with SHG. It is an important method with which to evaluate the effects of new procedures and treatments.
The now common use of transvaginal ultrasound for screening for endometrial neoplasia or hyperplasia in postmenopausal women uncovers some women with thin but asymmetrical or poorly imaged endometrium. Delineation of the cavity with SHG eliminates or demonstrates the need for biopsy in these few unclear instances. SHG can demonstrate a smooth endometrial surface and symmetrical thickness that are as reassuring in postmenopausal women as they are in younger cycling women. The Society for Radiologists in Ultrasound consensus statement on use of ultrasound for evaluation of abnormal bleeding indicates that transvaginal sonography and sonohysterography may be used in the initial evaluation of postmenopausal bleeding (Figure 38-1).41
Society for Radiologists in Ultrasound algorithm for evaluation of postmenopausal bleeding. Reproduced from: Goldstein RB, Bree RL, Benson CB, Benacerraf BR, Bloss JD, Carlos R et al. Evaluation of the woman with postmenopausal bleeding: Society of Radiologists in Ultrasound-Sponsored Consensus Conference statement. J Ultrasound Med 2001; 20(10):1025-1036.
Women undergoing treatment with tamoxifen constitute a special category. The unpredictably agonistic effects of this estrogen receptor blocker stimulate endometrial proliferation, polyp formation, and possible cancer in some women. Sonohysterography is a useful technique for evaluation of patients on tamoxifen. The endometrium may have a bizarre cystic appearance on unenhanced transvaginal sonography examination. However, it is actually the subendometrial region that appears abnormal and the endometrium itself is often thin and atrophic. In a study of 48 consecutive tamoxifen-treated women, the authors found that sonohysterography aids in the diagnosis of endometrial abnormalities even if prior endometrial biopsies were negative.42 Surgery was avoided in 14% of the subjects when the SHG revealed a normal endometrium or subendometrial cysts. Markovitch et al studied the value of sonohysterography in screening asymptomatic postmenopausal tamoxifen-treated breast cancer patients.43 In 85 patients with an endometrial thickness of greater than 8 mm the authors found that sonohysterography improves the accuracy of diagnosis of an intrauterine mass. SHG was found to be a highly specific technique for detection of abnormalities in tamoxifen-treated patients.
The location of an unextractable IUD among myomata or embedded in the uterine wall can be verified, and operative hysteroscopy can be planned using SHG.
Contraindications to Sonohysterography
There are few contraindications to SHG.44 These include the following:
Known or suspected pregnancy
Infection or pelvic pain suggestive of pelvic infection
Intractable cervical stenosis
A few common items are needed in addition to a gynecologic exam table equipped with stirrups, a basin, and adjustable head height, and an ultrasound machine with a vaginal probe. Also needed are a speculum and cervical cleanser with swabs, a sterile long packing or ring forceps, a catheter, injectable-grade sterile saline, a 10-cc sterile syringe for small uteri or a 40-cc sterile syringe for lar-ger ones.
To allow atraumatic pelvic manipulation by the ultrasound probe, catheters must be flexible, narrow, and at least 25-cm long. Any sterile straight catheter with a diameter of 2 mm can be used, for instance, the Tampa catheter, which has an introducer (Ackrad Labs, Inc, Cranford, NJ, USA); or a Soules intrauterine insemination catheter (Cook Co, Spencer, IN, USA); or a 25-cm, 5.3 French atraumatic catheter. There is a movable silastic marker collar 7 cm from the tip. This is for small uteri with normal internal ostia and can be used in about 90% of cases. A plastic premature infant feeding tube (Davol Inc, Cranston, RI, USA); 5 French catheter, 38-cm long; or any other narrow, long, flexible catheter that will accept a syringe may be used. The Davol catheter has a mark 8 inches from the tip. A 2-mm semiflexible plastic biopsy curet, such as a Milex Exploracuret (Milex Products, Inc, Chicago, IL, USA), is a little more uncomfortable but will work as well if biopsy is anticipated. Straight catheters allow discharge of the fluid through the cervix and into the basin, which prevents overdistention, tubal reflux, and cramping.
In women with patulous cervices, uteri longer than 8 cm, or suspected synechiae, a balloon catheter is required for adequate distention. An H/S catheter (Ackrad Co, Cranford, NJ, USA) is a 5.3 French flexible hysterosalpingogram catheter with a 3-cc latex or spindle-shaped plastic balloon. This catheter is also recommended for infusion for evaluation of tubal patency and intraperitoneal disease. An 8 French pediatric Foley catheter with a 3-cc balloon can also be used successfully in lieu of the H/S catheter. If Asherman syndrome is suspected, it will allow adequate separation of the tethered uterine surfaces. These balloons can also be used to gently dilate the cervical canal so that larger biopsy instruments can be passed.
The Goldstein Sonobiopsy Catheter (Cook Medical Inc, Bloomington, IN, USA) is 7.2 French, and 26-cm long (Figure 38-2). Instead of a balloon tip, it has an acorn-shaped silicone positioner that is placed against the cervix to prevent fluid backflow.
Dessole et al compared 6 different types of catheters for SHG (Figure 38-3).45 They assessed reliability, physician's ease of use, time required for insertion of the catheter, volume of contrast medium used, tolerability for the patient, and the cost. No statistically significant differences were found among the catheters. The Foley catheter was the most difficult to use and required the most time to position correctly. The Goldstein catheter was best tolerated by the patients. The Foley catheter was the least expensive.
Catheters for sonohysterography. A: Foleycath (Wembley Rubber Products; Sepang, Malaysia). B: Hysca Hysterosalpinography Catheter (GTA International Medical Devices S.A., La Caleta D.N., Dominican Republic). C: H/S Catheter Set (Ackrad Laboratories, NJ). D: PBN Balloon Hystero-Salpingography Catheter (PBN Medicals, Stenloese, Denmark). E: ZUI-2.0 Catheter (Zinnanti Uterine Injection, BEI Medical System International, Gembloux, Belgium). F: Goldstein Catheter (Cook, Bloomington, IN). (Image reprinted from: Dessole S, Farina M, Capobianco G, Nardelli GB, Ambrosini G, Meloni GB. Determining the best catheter for sonohysterography. Fertil Steril 2001; 76:605-609.)
As with hysteroscopy, lesions arising from the endometrium are best defined against minimally stimulated or postmenstrual endometrium. A history is taken, and the procedure is explained, at which time a rapid urine human chorionic gonadotropin assay is done if there is a strong likelihood of pregnancy. The patient is examined in the dorsal lithotomy position. A baseline transvaginal ultrasound exam is done, during which there is careful evaluation of the uterus, ovaries, and tubes for morphology, mobility, and pain. The posterior cul-de-sac is inspected for free fluid.
The speculum is then introduced in the vagina and the external cervical os is visually identified. The speculum can be manipulated to optimally expose and immobilize the cervix.
The vagina is then inspected for sources of bleeding, and the cervix for yellow mucus that would suggest Chlamydia infection. If pain or cervical discharge suggests pelvic infection, the procedure is delayed until diagnosis and therapy have been accomplished.
The cervix is cleaned with iodine solution or other antiseptic. The catheter is then slowly advanced into the cervix. The catheter is threaded through the cervix with a sterile ring or packing forceps. The catheter should be flushed with saline before insertion to decrease the echogenic artifact caused when air is initially injected into the cavity. A straight catheter should be advanced until its tip is in the fundus; a balloon catheter should have the balloon placed in the midcervix and gently inflated with fluid (not air) until meeting resistance. While the catheter is held in place with forceps, the speculum is carefully removed and the vaginal probe is reintroduced above the catheter anterior to the cervix with an anteverted uterus, or below it and posterior to the cervix with a retroverted uterus. Video recording allows review for more careful analysis of details.
Optimal balloon catheter placement during SHG has been studied. Spieldoch et al randomized women undergoing SHG to intracervical or intrauterine balloon catheter placement. There was significantly less pain with intracervical balloon placement.46 Significantly, less saline was required with intracervical catheter placement.
A small (50- to 250-cc) bag of intravenous fluid can be hung in the lab and used as needed if sterile technique is used for saline withdrawal into a 10- to 40-cc syringe. The syringe is attached to the catheter, and the saline is slowly infused while scanning the uterus longitudinally, fanning from cornu to cornu. The transducer is then turned 90 degrees, and the uterus is scanned in a transverse fashion from the external os of the cervix to the fundus during infusion, while the cavity is examined for asymmetry or unusual shape.
Each cornu is identified and the uterotubal junction and interstitial part of the tube are sought to confirm a normally shaped cavity. A three-dimensional mental image of the cavity is thus assembled, and lesions are precisely located. Rapid cervical expulsion of the saline can be partly prevented by pressure with the probe on the internal os while scanning longitudinally. A cervical balloon may be required if distention cannot be maintained. Two to 8 cc in the cavity is enough to outline most lesions; unlike the case in hysteroscopy, overdistention of the uterus is not required. Even a small rim of fluid will serve as an interface to allow cavitary assessment. Repetitive injection of small amounts of fluid using a 40- to 60-cc syringe is not difficult if one prefers not to use a balloon, and for this an assistant is very helpful. It is important to deflate the balloon under direct visualization to evaluate the lower uterine cavity and cervix at the end of the procedure so as not to miss pathology in these regions potentially obscured by the balloon.
Significant imaging artifacts preventing accurate interpretation may arise if a substantial amount of air is inadvertently introduced into the lumen prior to instillation of saline. If the lumen is filled with air, the procedure may need to be aborted and repeated the next day, allowing for air to escape from within the lumen. Occasionally, the injected air can be aspirated successfully.
If biopsy is being considered, 10 cc of 1% lidocaine can be infused as the distending medium in nonallergic individuals. Guney et al randomized patients to receive intrauterine lidocaine or saline at the time of SHG. They found modest reductions in pain scores both immediately after the procedure and 20 minutes later.47 Residual intrauterine fluid should be aspirated, if possible, before withdrawing the catheter if a Pipelle curet with limited volume will be used for biopsy. Nicoletti et al developed a new technique to obtain directed biopsy during sonohysterography.48 They developed the NiGo forceps, which has a length of 35 cm and an outer diameter of 7 French (Figures 38-4 and 38-5). An irrigation channel allows for expansion of the uterine cavity with distention media. The biopsy forceps permits taking tissue samples of approximately 6 to 8 mm maximum diameter. They performed SHG and hysteroscopy on 18 patients. SHG was successful using the NiGo device in 15 of the 18 women and an endometrial sample was obtained in 14 of these patients. In one patient endometrial biopsy provided too little tissue for pathologic evaluation. All adequate samples obtained with the device were identical to those obtained in hysteroscopy. It also should be noted that the office-based hysteroscopy procedure was not successful in 2 of the patients.
NiGo catheter for obtaining biopsies during sonohysterography. (Reproduced from: Nicoletti L, Gorlero F, Lijoi D, Nicoletti A, Lorenzi P, Ragni N. A new technique to obtain endometrial directed biopsy during sonohysterography: the NiGo device. J Minim Invasive Gynecol 2006; 13(6):505-509.)
Close up view of the tip of the NiGo catheter biopsy forcep. (Reproduced from: Nicoletti L, Gorlero F, Lijoi D, Nicoletti A, Lorenzi P, Ragni N. A new technique to obtain endometrial directed biopsy during sonohysterography: the NiGo device. J Minim Invasive Gynecol 2006; 13(6):505-509.)
Leone et al performed endometrial sampling on 128 patients with a diffusely thickened or inhomogeneous endometrium at the time of sonohysterography.49 A 14 French urinary catheter was used for the SHG and also to perform directed sampling of the endometrium. They compared the results from the SHG-directed sampling to that obtained at office hysteroscopy. The median area of endometrial specimens obtained by SHG was not significantly different than that obtained at hysteroscopy. There was good correlation in pathologic diagnoses between the samples obtained using the 2 different techniques. Another study examined the use of the Uterine Explora curette (Milex, Chicago, IL, USA) to guide endometrial biopsy at the time of SHG or to remove intraluminal masses. In 20 patients this technique was successful in biopsying endometrial filling defects without the need for hysteroscopy.50
Use of 3D Imaging in Sonohysterography
Three-dimensional rendering of volume-acquired images has been used to further refine the technique of SHG. Three-dimensional imaging has the advantage of providing a true coronal plane, which is not always possible using two-dimensional (2D) imaging. Surface rendering, while useful in obstetrical imaging, does not play a major role for SHG. Lev-Toaff et al compared 3D SHG to 2D SHG and HSG.51 They found that in 9 of 13 comparisons between 3D SHG and 2D SHG, and in 11 of 12 comparisons between 3D SHG and HSG, the 3D technique was advantageous. It was easier to identify müllerian anomalies and to localize pathology. In some cases small intracavitary masses were identified with the 3D technique, yet not with the 2D technique.
An additional advantage of 3D imaging is the ability to interpret the images after the study is completed. A 3D volume set may be acquired quickly and then the catheter and probe removed. The volume set may then be viewed and interpreted at a later time. This may minimize discomfort for the patient. It also may increase the efficiency of the scanning laboratory.52
Sylvestre et al examined 209 infertile patients with 2D and 3D SHG and compared the findings with those found at surgery.53 They found that 3D SHG allowed more precise recognition and localization of lesions. They found 2 more polyps with the 3D technique. The sensitivity of 2D SHG was 98% and the sensitivity of 3D SHG was 100%.