Evaluation of tubal patency by hysterocontrast sonography (HyCoSy, Echovist) and its correlation with laparoscopic findings

Oil-based or saline contrast for sono-hysterosalpingography in infertile women: a pilot randomized controlled double blind trial

Objective

To determine the feasibility, safety, and outcomes of an oil-based, iodinated contrast using office-based, ultrasound-imaged hysterosalpingography in women with infertility.

Design

Randomized Controlled Double Blind Clinical Trial.

Setting

Academic health center.

Interventions

Tubal flushing with oil-based contrast medium (Lipiodol UF) versus saline.

Main Outcome Measures

Ongoing pregnancy rate, pain, quality of life, and thyroid function.

Results

Forty-eight patients (24 in each group) were analyzed. The groups were well-matched at baseline. Ongoing pregnancy was noted in 17% (4/24) of the oil-contrast group versus 37% (9/24) in the saline group. Saline group patients more frequently initiated infertility therapy in the six-month follow-up period (saline, 67% vs. oil, 33%), and no serious adverse events in either group. There were no differences in pain from the procedure between groups. There were no differences in thyroid function tests postprocedure between groups, but within the oil-contrast group, there was a slight increase in thyroid-stimulating hormone (post vs. preratio of geometric means: 1.18; 95% confidence interval [CI], 1.02-1.38) and decrease in Free T4 (postdifference vs. predifference in means: 0.08 ng/dL; 95% CI, -0.14 to -0.01). Immediately after the test, the physicians correctly guessed 79% of oil and 71% of saline randomization assignments, whereas patients correctly guessed 63% of oil and 38% of saline.

Conclusions

This pilot study demonstrates the safety and feasibility of giving an oil-based contrast medium during ultrasound-imaged hysterosalpingography. Pregnancies were seen after oil-based administration, and this contrast is associated with minor thyroid function impairment.

Severe pain during hysterosalpingo-contrast sonography (HyCoSy): a systematic review and meta-analysis

PURPOSE

To assess the frequency of severe pain perception during hysterosalpingo-contrast sonography (HyCoSy) in infertile women and to assess whether there are differences in the frequency of associated pain according to the contrast used.

DESIGN

Systematic review and meta-analysis.

PATIENTS

Women undergoing HyCoSy due to infertility.

INTERVENTIONS

Searches were carried out in two databases (Pubmed and Web of Science). We included prospective or retrospective cohort observational studies that specified the type of contrast used during HyCoSy and reported data regarding the number of patients who perceived severe pain during the procedure and the scale used for pain perception score.

MAIN OUTCOME MEASURES

Pooled frequency of severe pain perception during HyCoSy and the pooled frequency of severe pain perception based on the contrast used.

RESULTS

Twenty-nine studies were included in this meta-analysis including a total of 7139 patients. In 10 studies, Saline solution with air was used as contrast EchoVist™ was used in ten studies, in five studies, SonoVue™ was used and in four studies, ExEm-Foam™ was used as contrast. Pooled estimated frequency of severe pain perception during HyCoSy was 6% (95% CI 4-9). No statistically significant differences have been described regarding frequency of severe pain perception in relation to the different contrasts used.

CONCLUSIONS

HyCoSy is a tolerable outpatient procedure. We did not find any evidence that one specific contrast was better tolerated than any other was.

Two-dimensional hysterosalpingo-contrast-sonography compared to three/four-dimensional hysterosalpingo-contrast-sonography for the assessment of tubal occlusion in women with infertility/subfertility: a systematic review with meta-analysis

In this meta-analysis, we aimed to compare the diagnostic accuracy of 2D- and 3D/4D-HyCoSy for the assessment of tubal occlusion in women with infertility, using a laparoscopic tubal chromoperturbation dye test as the reference standard. Studies assessing 2D- and 3D/4D-HyCoSy for the assessment of tubal occlusion in women with infertility were searched from January 1990 to April 2019 using Medline and Web of Science databases by three of the authors, using the terms: 'hysterosalpingo-contrast-sonography', 'sonohysterosalpingography', 'HyCoSy', 'HyFoSy', 'three-dimensional', 'four-dimensional', 'ultrasound', 'tubal patency' and 'tubal occlusion'. Data quality was determined using the QUADAS-2 tool. Thirty articles were included; twenty-one studies used 2D-HyCoSy to assess tubal occlusion, six used 3D/4D-HyCoSy, one study used both techniques but in a different set of patients and two used both techniques in the same patients. The risk of bias for most studies was low as determined by QUADAS-2, except for the patient selection domain. Overall, pooled estimated sensitivity and specificity of 2D-HyCoSy were 86% (95% CI = 80%-91%) and 94% (95% CI = 90%-96%), respectively. The corresponding figures for 3D/4D HyCoSy were 95% (95% CI = 89%-98%) and 89% (95% CI = 82%-94%). High heterogeneity was found for both sensitivity and specificity. No statistically significant differences were found between the methods (p = 0.13). We concluded that 2D-HyCoSy has a similar diagnostic performance to 3D/4D-HyCoSy.

Comparison of sonohysterography to hysterosalpingogram for tubal patency assessment in a multicenter fertility treatment trial among women with polycystic ovary syndrome

PURPOSE

To compare saline infusion sonohysterography (SIS) versus hysterosalpingogram (HSG) for confirmation of tubal patency.

METHODS

Secondary analysis of a randomized controlled trial, Pregnancy in Polycystic Ovary Syndrome II (PPCOS II). Seven hundred fifty infertile women (18-40 years old) with polycystic ovary syndrome (PCOS) were randomized to up to 5 cycles of letrozole or clomiphene citrate. Prior to enrollment, tubal patency was determined by HSG, the presence of free fluid in the pelvis on SIS, laparoscopy, or recent intrauterine pregnancy. Logistic regression was conducted in patients who ovulated with clinical pregnancy as the outcome and HSG or SIS as the key independent variable.

RESULTS

Among women who ovulated, 414 (66.9%) had tubal patency confirmed by SIS and 187 (30.2%) had at least one tube patent on HSG. Multivariable analysis indicated that choice of HSG versus SIS did not have a significant relationship on likelihood of clinical pregnancy, after adjustment for treatment arm, BMI, duration of infertility, smoking, and education (OR 1.14, 95% CI 0.77, 1.67, P = 0.52). Ectopic pregnancy occurred more often in women who had tubal patency confirmed by HSG compared to SIS (2.8% versus 0.6%, P = 0.02).

CONCLUSIONS

In this large cohort of women with PCOS, there was no significant difference in clinical pregnancy rate between women who had tubal patency confirmed by HSG versus SIS. SIS is an acceptable imaging modality for assessment of tubal patency in this population.

B-flow ultrasound facilitates visualization of contrast medium during hysterosalpingo-contrast sonography

OBJECTIVE

To assess if B-flow ultrasound improves visualization of flow of contrast medium in the Fallopian tubes during hysterosalpingo-contrast sonography (HyCoSy) compared with grayscale ultrasound.

METHODS

This prospective observational study included 160 women referred for HyCoSy as part of infertility work-up between January 2011 and September 2012. In each woman, at the same session, HyCoSy was performed first using saline with air and then using Sonovue®, and for each contrast medium, grayscale ultrasound was first used and then B-flow ultrasound was used. Flow of contrast was observed in three parts of each tube: intramural, middle and distal.

RESULTS

In 129 (81%) women, flow of Sonovue was observed in the intramural part of both tubes and in the pouch of Douglas when using grayscale ultrasound. In these women, flow of Sonovue was seen in the middle part of 70% of the 258 tubes when using grayscale ultrasound and in 93% when using B-flow ultrasound; and in the distal part in 81% when using grayscale ultrasound and in 98% when using B-flow ultrasound. When using air and saline, flow was seen in the intramural part of 90% and 93% of the tubes, in the middle part in 54% and 72%, and in the distal part in 66% and 90%, using grayscale ultrasound and B-flow ultrasound, respectively.

CONCLUSION

B-flow ultrasound facilitates detection of flow of contrast in the middle and distal parts of the tubes at HyCoSy, especially when a mixture of saline and air is used as contrast medium.

Automated three-dimensional coded contrast imaging hysterosalpingo-contrast sonography: feasibility in office tubal patency testing

OBJECTIVE

To evaluate the feasibility of transvaginal hysterosalpingo-contrast sonography (HyCoSy) with new automated three-dimensional coded contrast imaging (3D-CCI) software in the evaluation of tubal patency and visualization of tubal course.

METHODS

Patients undergoing HyCoSy with automated 3D-CCI software were evaluated prospectively. First, to evaluate the feasibility of 3D visualization of tubal course, we performed consecutive volume acquisitions while injecting SonoVue contrast agent. We then performed conventional two-dimensional (2D) real-time HyCoSy to confirm tubal patency status by detection of saline and air bubbles moving through the Fallopian tubes and around the ovaries. We also evaluated visualization with CCI of the contrast agent around the ovaries, side effects and pain during and after the procedure, by visual analog scale (VAS) (ranging from 0 to 10, with 0 corresponding to no pain and 10 corresponding to maximum pain).

RESULTS

A total of 126 patients (252 tubes) underwent 3D-CCI HyCoSy followed by 2D real-time HyCoSy. According to the final 2D real-time evaluation, bilateral tubal patency was observed in 111 patients, bilateral tubal occlusion in four patients and unilateral tubal patency in 11 patients. The concordance rate for tubal patency status between the first 3D volume acquisition and the final 2D real-time evaluation was 84% and that between the second 3D volume acquisition and the final 2D real-time evaluation was 97%. A pain score >5 on VAS was recorded in 58% of patients during the procedure, but a pain score ≤ 5 was recorded in 85.7% of patients immediately after the procedure.

CONCLUSIONS

HyCoSy with automated 3D-CCI technology retains the advantages of conventional 2D HyCoSy while overcoming the disadvantages. 2D HyCoSy is highly observer-dependent and is only accurate in the hands of experienced investigators; by obtaining a volume of the uterus and tubes, automated 3D volume acquisition permits visualization of the tubes in the coronal view and of the tubal course in 3D space, and should allow less experienced operators to evaluate tubal patency status relatively easily.

Diagnosis of hepatic hydrothorax using contrast-enhanced ultrasonography with intraperitoneal injection of Sonazoid

BACKGROUND AND AIM

We investigated the utility and safety of contrast-enhanced ultrasonography using Sonazoid in the diagnosis of hepatic hydrothorax.

METHODS

The study consisted of seven liver cirrhosis patients with hydrothorax and hydroperitoneum. After obtaining informed consent, Sonazoid was injected intraperitoneally, and enhancement in the peritoneal and pleural cavities was observed.

RESULTS

In all patients, the peritoneal cavity was quickly enhanced after the Sonazoid injection. The pleural cavity was enhanced in five of the seven patients, and these five patients were diagnosed with hepatic hydrothorax. Two patients without enhancement of the pleural cavity were diagnosed with inflammatory hydrothorax.

CONCLUSIONS

This is the first report to confirm transdiaphragmatic movement of ascitic fluid into the pleural cavity using contrast-enhanced ultrasonography with Sonazoid. This method can safely detect ascitic flow in real time, and is thus very useful for the diagnosis of hepatic hydrothorax.

Hysterosalpingocontrastsonography in clinical practice

The aim of this study was to review the indication, source of referral and findings at hysterosalpingocontrastsonography (HyCoSy) of the first 100 patients referred for this new service in the gynaecological outpatients department of the Coombe Women's Hospital, Dublin. Of the first 100 women referred for HyCoSy, the indication for referral was investigation of infertility in 72%, recurrent miscarriage in 22% and other reasons in 6%. Sixty-four women were referred from general gynaecological clinics, 29 from the specialised infertility clinic and seven women were referred from other hospitals. The procedure was completed in 97% of cases and tubal patency successfully assessed in 95%. Saline hysterosonography was performed in 96 cases. Tubal assessment with Echovistt showed bilateral tubal patency in 73%, bilateral occlusion in 10% and unilateral patency in 12%. All women were discharged within 30 minutes of the procedure. We concluded that hysterosalpingocontrastsonography is an easily introduced, successful outpatient technique, which is well tolerated by women and provides clinically relevant information in women with infertility or recurrent miscarriage.

The management of hydrosalpinges: tubal surgery or salpingectomy?

PURPOSE OF REVIEW

The clinical management of hydrosalpinges in infertile patients remains a contentious issue. This review aims to provide a critical analysis on the available treatments for hydrosalpinges, which have recently created a fierce debate between the promoters of salpingectomy and in-vitro fertilization and those who endorse tubal surgery.

RECENT FINDINGS

Hydrosalpinges have a detrimental effect on the outcome of in-vitro fertilization yet their mechanism is still unclear. Salpingectomy prior to in-vitro fertilization restores the likelihood of a successful outcome in a well defined group of patients with ultrasound-visible hydrosalpinges. However, not every woman with large hydrosalpinges should undergo salpingectomy as some fallopian tubes may be amenable to surgical repair. Preserved tubal mucosa indicates a good prognosis for tubal surgery, therefore an appropriate mucosal assessment should be routine prior to deciding upon further management.

SUMMARY

As salpingectomy is a definitive procedure it should be performed when the hydrosalpinges are beyond repair or in cases of in-vitro fertilization failure. Tubal surgery should be preferred to salpingectomy in mild to moderate tubal disease. A comparative study of restorative tubal surgery versus salpingectomy and in-vitro fertilization in selected women with hydrosalpinges is needed and will significantly help this debate. Prophylactic salpingectomy prior to in-vitro fertilization and tubal surgery is not competing but complementary in the treatment of hydrosalpinges-related infertility.

Contrast infusion sonography to assess microinsert placement and tubal occlusion after Essure®

OBJECTIVE

To develop a technique for contrast infusion sonography and assess the possible use in determining microinsert placement and tubal status after Essure sterilization.

DESIGN

Techniques and instrumentation.

SETTING

Healthy women in an academic multispecialty group.

PATIENT(S)

Ten women desiring permanent sterilization who have recently undergone Essure hysteroscopic sterilization.

INTERVENTION(S)

Contrast infusion sonography, an adaptation of hysterosalpingo contrast sonography, performed at 3-23 weeks after Essure placement.

MAIN OUTCOME MEASURE(S)

To determine how readily tubal status and microinsert location could be assessed with this adaptation of hysterosalpingo contrast sonography.

RESULT(S)

All microinserts were readily identified and tubal status was assessed by identification or absence of real-time contrast agent flow.

CONCLUSION(S)

This technique is very promising and could represent a convenient alternative to hysterosalpingogram (HSG) 3 months after Essure placement.

Comparison of three-dimensional hysterosalpingo-contrast-sonography and diagnostic laparoscopy with chromopertubation in the assessment of tubal patency for the investigation of subfertility

BACKGROUND

Two-dimensional hysterosalpingo-contrast-sonography, as a screening test for tubal patency for subfertile patients, is limited by the difficulty in visualizing the entire Fallopian tube owing to its tortuosity. This major disadvantage can be overcome by means of the three-dimensional hysterosalpingo-contrast-sonography (3D-HyCoSy). The current study compared the efficacy of 3D-HyCoSy with diagnostic laparoscopy and its feasibility as a screening test for tubal patency.

METHODS

Twenty-one consecutive patients scheduled to have laparoscopy were recruited to undergo the 3D-HyCoSy 2 days before the scheduled laparoscopy. Echovist (Schering AG, Berlin, Germany), the ultrasound contrast medium, was injected into the uterine cavity via a Foley's catheter. The flow of the medium in the Fallopian tube was captured by using three-dimensional power Doppler mode and was stored for later analysis. The person analyzing the images, the surgeon performing the laparoscopy, and the patients were blinded to the patients' identity and the sonography findings. The sonography and the laparoscopy findings were compared. The duration for the ultrasound examination, pain score, and patient acceptability were assessed.

RESULTS

Thirty-four of 42 (81%) Fallopian tubes were assessed. The sensitivity of 3D-HyCoSy for detecting tubal patency was 100% with a specificity of 67%. The positive and negative predictive values were 89 and 100%, respectively; the concordance rate was 91%. The mean duration (+/- SD) for the 3D-HyCoSy was 13.4 +/- 5.5 min. Fifteen patients (71%) regarded the sonography examination as at least acceptable.

CONCLUSIONS

This study confirmed the feasibility of using 3D-HyCoSy as an initial investigation for tubal patency.

Evidence-based diagnosis and management of tubal factor infertility

PURPOSE OF REVIEW

The investigation for potential tubal disease is an essential step in the work-up of infertility. This review article provides an evidence-based overview of the diagnosis and management of tubal factor infertility.

RECENT FINDINGS

While laparoscopic chromopertubation remains the gold standard in the diagnosis of tubal disease and hysterosalpingography is still widely used, newer modalities offer some advantages. Sonohysterography with the use of contrast medium is superior to hysterosalpingography and comparable to laparoscopic chromotubation in diagnosing tubal blockage. Chlamydia serology is the most cost-effective and least invasive diagnostic test for tubal disease, and it is comparable to, if not better than, hysterosalpingography. Depending on the nature and degree of tubal dysfunction as well as the age and ovarian reserve of the patient, various treatments for tubal infertility are available. For proximal tubal obstruction, transcervical tubal cannulation with tubal flushing is a reasonable first approach. Surgical techniques for tubal repair, such as salpingostomy or fimbrioplasty for distal tubal obstruction, can provide good results. Still, tubal factor remains a major indication for in-vitro fertilization and embryo transfer, which bypasses the tubal problem altogether. In certain situations, such as the presence of hydrosalpinx, prophylactic surgery can be used in conjunction with in-vitro fertilization and embryo transfer.

SUMMARY

As with infertility in general, the diagnosis and management of tubal infertility should be tailored to the individual patient. Future studies should help to further clarify the role of the various diagnostic tests and therapeutic approaches for tubal infertility.

Effect of treatment of intrauterine pathologies with office hysteroscopy in patients with recurrent IVF failure

The study was conducted to evaluate if the diagnosis and treatment of intrauterine lesions with office hysteroscopy is of value in improving the pregnancy outcome in patients with recurrent in-vitro fertilization and embryo transfer failure. Four hundred and twenty-one patients who had undergone two or more failed IVF-embryo transfer cycles were prospectively randomized into two groups. Group I (n = 211) did not have office hysteroscopic evaluation, Group II (n = 210) had office hysteroscopy. The patients who had normal hysteroscopic findings were included in Group IIa (n = 154) and patients who had abnormal hysteroscopic findings were included in Group IIb (n = 56). Intrauterine lesions diagnosed were operated during the office procedure. Fifty-six (26%) patients in Group II had intrauterine pathologies and the treatment was performed at the same time. No difference existed in the mean number of oocyte retrieved, fertilization rate, number of embryos transferred or first trimester abortion rates among the patients in groups. Clinical pregnancy rates in Group I, Group IIa and Group IIb were 21.6%, 32.5% and 30.4% respectively. There was a significant difference in the clinical pregnancy rates between patients in Group I and Group IIa (21.6% and 32.5%, P = 0.044, respectively) and Group I and Group IIb (21.6% and 30.4%, P = 0.044, respectively). There was no significant difference in the clinical pregnancy rate of patients in Groups IIa and IIb. Patients with normal hysterosalpingography but recurrent IVF-embryo transfer failure should be evaluated prior to commencing IVF-embryo transfer cycle to improve the clinical pregnancy rate.

Hysterosalpingo-Contrast Sonography Compared with Hysterosalpingography and Laparoscopic Dye Pertubation to Evaluate Tubal Patency

STUDY OBJECTIVE

To evaluate the advantages and accuracy of hysterosalpingo-contrast sonography (HyCoSy) in assessing tubal patency compared with hysterosalpingogram (HSG) and laparoscopic dye pertubation.

DESIGN

Prospective study (Canadian Task Force classification II-2).

SETTING

Obstetrics and Gynecology Department, University of Rome Tor Vergata.

PATIENTS

Twenty-three women with at least 1 year of infertility, and 15 women with a history of chronic pelvic pain, suspected endometriosis, or pelvic inflammatory disease (PID), or with sonographic markers of adhesions.

INTERVENTIONS

HyCoSy, HSG, and laparoscopic dye pertubation.

MEASUREMENTS AND MAIN RESULTS

All patients underwent HyCoSy during the proliferative phase using air with saline as contrast medium, and HSG within 1 month of HyCoSy. Laparoscopy and dye pertubation were performed only in women with chronic pelvic pain, suspected endometriosis, PID, and sonographic markers of adhesions. In women undergoing all three procedures, HSG and HyCoSy had the same high concordance as laparoscopy, 86.7% and 86.7%, respectively. Three women in the infertility group became pregnant immediately after HyCoSy and dropped out of the study. In one woman, HyCoSy could not be performed because of cervical stenosis. Considering the total number of tubes (67), concordance between HyCoSy and HSG was 89.6%.

CONCLUSION

Transvaginal HyCoSy using a combination of air and saline appears to be an inexpensive, fast, and well-tolerated method of determining tubal patency. One of the most important advantages of this technique is, in our opinion, the possibility of obtaining information on tubal status and the uterine cavity at the same time as conventional ultrasound scan is performed.

Assessment of Fallopian tube patency by HyCoSy: comparison of a positive contrast agent with saline solution

OBJECTIVE

To compare the efficiency of air-filled albumin microspheres (Infoson) with saline solution in determining Fallopian tube patency during hysterosalpingo contrast sonography (HyCoSy).

METHODS

This was a prospective randomized multicenter study with a sequential design. Over a 10-month period, 23 patients (mean age, 33 years) referred for infertility were examined by HyCoSy (saline or Infoson) before conventional hysterosalpingography (Iopamiron 370), performed during the same session. Contrast agents were administered through a 5-F Ackrad balloon catheter inserted transcervically into the uterine cavity. HyCoSy was performed with a 7-MHz transvaginal probe using both B-mode and color Doppler, and tubal patency was demonstrated by the appearance of contrast agent in the peritoneal cavity near the ovaries. Data were registered for each patient during the examination and the results were monitored by sequential analysis.

RESULTS

Mean volumes of contrast injections were 35.3 mL of saline, 14.4 mL of Infoson, and 13.8 mL of Iopamiron 370. Infoson-enhanced HyCoSy provided a significantly larger (P = 0.006) number of correct diagnoses (20/22 Fallopian tubes) than did saline HyCoSy (12/24 Fallopian tubes), and the same number as that achieved by hysterosalpingography.

CONCLUSION

A positive ultrasound contrast agent appears to be more efficient than saline solution at determining Fallopian tube patency in infertile women by means of HyCoSy, and as efficient as an iodinated contrast agent in the same population explored by HSG. HyCoSy could be used to screen infertile women, thereby avoiding the use of iodinated contrast medium and exposure to ionizing radiation during conventional HSG in patients with patent Fallopian tubes.

Can hysterosalpingocontrast-sonography replace hysterosalpingography in the assessment of tubal subfertility?

INTRODUCTION

Hysterosalpingo-contrastsonography (HyCoSy) is a new method for assessing tubal patency using transvaginal ultrasound. It is thought to have several advantages over conventional hysterosalpingography (HSG). We prospectively evaluated the performance of HyCoSy and HSG in the diagnosis of tubal pathology.

METHODS AND PATIENTS

One-hundred consecutive subfertile women underwent both HyCoSy and HSG in randomised order. Results of both tests were related to findings at laparoscopy with dye, which was used as the reference test. Each woman was asked to score the pain exsperienced at both procedures on a visual analogue scale.

RESULTS

When laparoscopy with dye was used as reference test, the likelihood ratios of HyCoSy were slightly inferior to those obtained for HSG. Since the performance of HyCoSy was dependent on experience, the results were recalculated omitting the 50 initial procedures from the analysis. In that calculation, results of HyCoSy and HSG were comparable. There were no differences in pain experienced during the procedure, as there appeared also to be no differences in patient preferences.

CONCLUSION

There appear to be no strong arguments either to replace HSG by HyCoSy, or to reject the use of HyCoSy. Both procedures can be used in the evaluation of tubal pathology.

Clinical experience with sonographic contrast agents

Early generations of sonographic contrast agents are beginning to reach the attention of the clinician. Research and development of ultrasound contrast agents is progressing at a rapid pace with several new agents approaching US Food and Drug Administration approval. Cardiac imaging has been affected by even the limited availability of contrast agents on the market today both with regard to diagnosis of shunts and chamber opacification, and most recently actual enhancement of the myocardium. Later generations of contrast are capable of providing consistent opacification of both peripheral veins and arteries, and should prove useful in a variety clinical applications. Thus far, it appears that longer vessel segments may be seen with contrast rather than without contrast, and that flow may be demonstrated in vessels which were not seen or thought to be occluded with conventional color imaging. Improved detection of arterial and venous collaterals and enhanced identification of run-off vessels is demonstrated with sonographic contrast agents. An improved ability to evaluate renal artery stenosis and subtotal occlusion of the carotid artery are specific advantages of using contrast as well. Several compounds are currently being tested that may allow routine parenchymal opacification. Ultrasound is the most commonly performed diagnostic imaging procedure; therefore, contrast agents have the potential to dramatically alter the practice of clinical medicine. This article reviews the current status of ultrasound contrast agents and speculates regarding the future applications of these agents.