Sonographic findings after surgical ablation of the endometrium

OBJECTIVE

Endometrial ablation is a new surgical technique that is an alternative to hysterectomy in women with dysfunctional uterine bleeding. The endometrium is either coagulated or resected in an attempt to render the patient amenorrheic. Because of the newness of the procedure, no report of radiologic findings after endometrial ablation has been published. Accordingly, the sonographic appearance of the uterus after endometrial ablation is described.

MATERIALS AND METHODS

Using transvaginal sonography, we examined a select group of 16 women, seven of whom were symptomatic after endometrial ablation. All patients had a preoperative diagnosis of menorrhagia not responsive to conventional hormonal therapy and no evidence of cancer.

RESULTS

In the seven symptomatic patients, sonography showed that postoperatively two had hematometra, one had a nonviable intrauterine pregnancy, and four had residual islands of functioning endometrial tissue alone or in combination with hematometra. In nine asymptomatic patients, postoperative sonography showed seven had normal findings except for leiomyomata and two had residual islands of functioning endometrial tissue.

CONCLUSION

Sonographic examination of the uterus after endometrial ablation provides a method for evaluating symptomatic patients and for identifying any remaining endometrium that could later become symptomatic.

Color Doppler imaging of the hepatic vasculature

Duplex sonography added a new dimension to real-time sonographic imaging and can be used to characterize flow dynamics. Unfortunately, duplex sonography also has significant drawbacks, most of which are the result of the limited sampling ability of pulse-gated technology and the inability to provide a global display of Doppler information. Sonographic imaging of intraabdominal vessels has improved markedly with the advent of color Doppler techniques. This article reviews the use of color Doppler sonography in the evaluation of hepatic vessels. The complementary role of Doppler spectral analysis is also considered.

Isolation of the fourth ventricle causing transtentorial herniation: neurosonographic findings in premature infants

OBJECTIVE

Significant posthemorrhagic enlargement of the fourth ventricle occurs only in a small minority of patients. Although entrapment or isolation of any ventricle can occur, the fourth ventricle is the most common site. This study was undertaken to better understand enlargement of the fourth ventricle after intraventricular hemorrhage and the neurosonographic features of isolation and transtentorial herniation.

MATERIALS AND METHODS

The sonographic records of 1535 premature neonates were reviewed for evidence of intracranial hemorrhage and ventriculomegaly. Cranial sonography was performed within the first 3 days of life in all neonates born in our hospital and within the first week of admission for transferred neonates. Follow-up sonograms were obtained at weekly intervals until discharge from the nursery. Intracranial hemorrhages were classified as severe when the hemorrhage was associated with hydrocephalus, intraparenchymal hemorrhage, or both.

RESULTS

Intracranial hemorrhage occurred in 761 (50%) of 1535 patients, with severe hemorrhages in 229. Ten had massive enlargement of the fourth ventricle with isolation in six of the 10 after shunt placement. Isolation of the fourth ventricle causing transtentorial herniation occurred in three. Of the patients with isolation of the fourth ventricle, two had associated infection and ventriculitis caused by Klebsiella oxytoca and one had Candida ventriculoencephalitis.

CONCLUSION

The early recognition of the neurosonographic features of an enlarged fourth ventricle causing transtentorial herniation has important therapeutic implications. Although isolation can occur after intraventricular hemorrhage alone, infection and ventriculitis are significant factors in the development of an isolated fourth ventricle.

Doppler ultrasonography of the pelvis

TVS has brought the pelvic organs closer to us than ever before. Color Doppler probes have exposed small vessels that could not be seen with real-time technique alone, and pulsed Doppler is becoming an important adjunct in many physiologic and pathologic states. Vascular changes of the ovary and uterus during the menstrual cycle are now being followed during infertility protocols, are being investigated to determine the viability of an early pregnancy, and may increase our confidence in the diagnosis of an ectopic pregnancy in a few selected cases. Waveform analysis may be useful in discriminating benign from malignant uterine masses, and additional work in the diagnosis of pelvic thrombophlebitis and ovarian torsion is anticipated. Color Doppler sonography has an important role to play in the diagnosis of early ovarian cancer. A large multicenter trial is ongoing in this country to determine if there is a characteristic PI that will determine whether an adnexal mass is benign. While much of this work is preliminary, TV-CDS has tremendous potential in the assessment of pelvic disease.

A new electronically enhanced biopsy system: value in improving needle-tip visibility during sonographically guided interventional procedures

Sonographically guided fine-needle biopsy procedures are hampered by poor visibility of the needle tip. This study was performed to evaluate a new system for placing needles under sonographic guidance. The Biosponder needle (Advanced Technology Laboratories, Bothell, WA) incorporates a specialized stylet with a passive sensor at its tip. When an ultrasound pulse is detected by the sensor, an electrical signal is transmitted to the sonographic unit by a battery-powered electronic module connected to the stylet and to the scanner. This signal is converted into a bright, flashing marker on the screen at the precise location of the needle tip. The Biosponder system, which uses 20- or 22-gauge needles, was compared with a 20-gauge Turner needle (Cook, Bloomington, IN) in 18 patients with masses or fluid collections and two patients requiring nephrostomy tube placement. The tip of the Turner needle could not be localized precisely in any patient. The shaft of the Turner needle was seen clearly in 13 patients, poorly in three, and was not visualized at all in four patients. Excluding four instances of mechanical failure, the Biosponder system allowed precise localization of the needle tip in every patient and was consistently rated as easier to use than the Turner needle. We conclude that the Biosponder needle, with its precise tip localization and ease of use, is a valuable tool for sonographically guided needle placement.

Case report 707: Hemorrhagic Baker's cyst of the right calf

A 50-year-old woman with juvenile rheumatoid arthritis presented with painful swelling of the right calf. Roentgenograms, sonograms, magnetic resonance images, and arthrograms were obtained. A diagnosis of hemorrhagic Baker's cyst was made, and surgical excision was performed. The etiology, clinical features, and radiological evaluation of simple and complicated Baker's cysts are discussed and the differential diagnosis considered.

Endoluminal catheter-assisted transcervical US of the human embryo. Work in progress

To enhance visualization of anatomic structures of the human embryo, the authors used a commercially available catheter-based ultrasound (US) transducer (12.5 MHz) introduced through the cervix and into the endometrial cavity of seven women about to undergo voluntary termination of first-trimester pregnancy. The authors term this technique endoluminal catheter-assisted transcervical (ELCAT) sonography. In none of the patients did the US catheter rupture the fluid-filled chorionic/amniotic cavity. The duration of pregnancy ranged from 5.2 to 10.0 menstrual weeks. The most prominent anatomic structures visualized were the heart and neural tube. As an investigational technique, ELCAT US can be used to image anatomic structures of the developing human embryo.

Detection of renal stones with real-time sonography: effect of transducers and scanning parameters

Three experiments with a variety of transducers and scanning parameters were designed to investigate if renal stones could be detected with greater certainty by using particular transducers or scanning parameters. First, the lateral resolution, derived from the -6-dB size of the beam profile, was measured at various depths for five transducers commonly used for renal sonography. Second, an in vitro test object was constructed from bovine liver, porcine kidneys, and two renal calculi to access gray-scale map effects on shadow visibility before and after storage in the digital scan converter. The third experiment combined 15 lithotripsy patients with known renal stones with 16 patients in whom the results of renal sonography and other radiographic procedures suggested renal calculi. The group of 15 patients was scanned several times with the transducers and gray-scale maps studied earlier, and the group of 16 patients was scanned only with one transducer and one gray-scale map. On radiographs, 12 of the 16 patients did not have renal calculi. Sonograms of the test object showed that low-contrast images were best for detection of posterior shadows. Three radiologists interpreted the 31 sonograms with a sensitivity of 81% and a specificity of 86% for detecting renal stones. For the 15 cases of renal stones scanned with a variety of transducers, the three radiologists found that annular-array transducers depicted stone shadowing with less ambiguity than mechanical sector transducers did 81% of the time.

Diagnosis of portal vein thrombosis: value of color Doppler imaging

This study was undertaken to determine the accuracy of color Doppler imaging in the diagnosis of portal vein thrombosis. Two hundred fifteen patients were studied with color Doppler imaging to determine patency of the main portal vein. Sonographic findings were confirmed in 75 patients, aged 19 to 66 years. Correlation with angiography was obtained in 13 patients, and surgical correlation was obtained in the remaining 62. Nine patients had portal vein thrombosis on the basis of these gold standards. Sonograms were classified as showing either patency or thrombosis, depending on the ability to show color flow within the main portal vein. Agreement between sonography and angiography or surgery was found in 69 patients (61 patent, eight thrombosed). One patient with a patent portal vein at sonography was found to have a thrombosed vessel at surgery, whereas five patients without portal venous flow at sonography had patent vessels at angiography (one patient) or surgery (four patients). Overall sensitivity and specificity for detection of portal vein thrombosis were 89% and 92%, with an accuracy of 92%, a false-negative rate of 0.11, a negative predictive value of 0.98, and a positive predictive value of 0.62. We postulate that the majority of errors in our study occurred in vessels that, although patent, had only sluggish flow, which could not be resolved because of technical limitations. We conclude that color Doppler imaging is a valuable screening procedure for the assessment of portal vein patency. If the sonogram shows a patent portal vein, no further studies are required. However, a lack of demonstrable flow does not always indicate thrombosis, and other imaging studies should be performed for confirmation.

Failure of duplex sonography to diagnose hepatic artery thrombosis in a high-risk group of pediatric liver transplant recipients

Excellent correlation between angiographic findings and duplex sonography has been previously reported in the diagnosis of hepatic artery thrombosis (HAT), the most common technical complication of pediatric orthotopic liver transplantation (OLT). We now report a significant incidence of false-negative sonograms, ie, hepatic artery reported as patent but thrombosed on subsequent angiography. HAT was diagnosed in 10 of 57 pediatric OLT recipients evaluated prospectively by duplex sonography. In 5 patients HAT was diagnosed only by angiography even though arterial wave forms were observed on duplex sonography. Selective angiography demonstrated extensive collateral vessel formation arising from the superior mesenteric artery, the celiac axis, or both. The 5 patients shared very similar clinical courses marked by relapsing bacteremias with multiple enteric organisms, associated with focal infarctions of the liver. Four of the grafts had difficult arterial reconstructions and 3 of 5 had segmental bile duct dilation. We conclude that duplex sonography has proven to be a valuable screening tool in evaluating hepatic artery patency but must be correlated with angiography studies in a high-risk group of pediatric transplant patients characterized clinically by relapsing bacteremia and radiographically by false-negative duplex examinations.

Maternal-fetal Doppler sonography: potential or reality

Doppler sonography, in its varying forms, has been used by numerous researchers to evaluate the maternal-fetal circulation. Unfortunately, as can be seen from this review, few sweeping conclusions can be drawn from the literature to date. Doppler certainly seems a worthwhile adjunct in the evaluation of patients with any of a number of abnormalities that affect maternal-fetal circulation. Unfortunately, considering the discrepancies in the literature and the recent controversy regarding the use of pulsed and color Doppler in pregnancy, the examination is often avoided. However, there are certainly instances where Doppler can provide unique and valuable information. In these situations, the prudent use of Doppler should be encouraged.

The pulsatile portal vein in cases of congestive heart failure: correlation of duplex Doppler findings with right atrial pressures

To better understand portal vein pulsatility in congestive heart failure, the authors compared portal vein spectral patterns to right atrial pressures measured with a Swan-Ganz catheter in 17 adult patients suspected of having congestive heart failure. Portal vein pulsatility was also evaluated in 17 healthy adults. A pulsatility score (scale, 1-5) based on a ratio of minimum to peak portal vein velocity was assigned. A score of 1 indicated continuous, monophasic flow, while a score of 5 indicated that flow reversal was observed with each cardiac cycle. All 17 healthy volunteers had portal vein pulsatility scores of 2 or less. Among the 17 patients suspected of having congestive heart failure, seven had normal right atrial pressure (less than 10 mm Hg) and pulsatility scores of 2 or less. Among the 10 patients with a right atrial pressure of 10 mm Hg or greater, six had pulsatility scores of 3 or greater (sensitivity, 60%; specificity, 100%). Greater than 50% of the variation in portal vein score is explained by changes in right atrial pressure. Review of echocardiograms in 13 of 17 patients showed no significant correlation between the degree of tricuspid regurgitation and portal vein score. Portal vein pulsatility is a sign of elevated systemic venous pressure.

Percutaneous nephrostomy in infants

We reviewed our experience with percutaneous nephrostomy placement in children less than one year of age during a five-year period. Placement was successful in 8 of 9 cases. There were no complications. The procedure favorably altered the outcome for each patient and was useful for reversing azotemia prior to surgical intervention for repair of an obstructed system (2 renal units), for providing drainage of pyonephrotic kidneys (3 renal units), for demonstrating inadequate recovery of renal function after relief of obstruction (2 renal units), and for replacing a surgically placed nephrostomy that was dislodged (1 renal unit). Our experience has encouraged us to accept the technique, and we believe that it is a valuable nonsurgical alternative that should be available to urologists managing infants with urinary tract pathology.

Duplex Doppler sonography in renal allografts: the significance of reversed flow in diastole

This study was undertaken to assess the significance of diastolic flow reversal seen on duplex Doppler sonograms of patients with renal transplant dysfunction. Earlier studies have evaluated the causes of increased vascular resistance in renal transplants. None, however, have investigated specifically the subset of patients in whom impedance in the renal microcirculation has increased to the degree that retrograde arterial flow is present. In our series, 533 consecutive scans in 270 patients were reviewed. The patients were referred for evaluation of renal transplant dysfunction during a 25-month period. Doppler samples were obtained from main, segmental, and, when possible, arcuate arteries. An episode of reversed diastolic flow was identified in nine patients. Correlation was made with clinical, laboratory, histologic (biopsy in six patients, nephrectomy in three patients), and imaging studies (DTPA scintigraphy in seven patients, angiography in one patient). On the basis of histologic and nephrectomy results, we determined that among the nine patients, four had acute tubular necrosis, three had acute rejection, and two had renal vein thrombosis. One of these patients had both severe rejection and renal vein thrombosis. One additional patient had neither biopsy nor nephrectomy and was not included in the diagnostic groups listed here. Our study suggests that reversed diastolic flow is not specific for either acute rejection or acute tubular necrosis. Reversal of diastolic flow, however, is a poor prognostic sign; nephrectomy was imminent in three of the nine patients. Furthermore, two (22%) patients had renal vein thrombosis, whereas renal vein thrombosis was not found in any of the 261 patients without reversed diastolic flow. Duplex Doppler examinations with reversed diastolic flow should suggest renal vein thrombosis.

Evaluation of renal transplant dysfunction by duplex Doppler sonography: a prospective study and review of the literature

A disconcertingly wide variation exists in the literature as to the accuracy of duplex Doppler sonography in the detection of acute renal transplant rejection. Sensitivities range from 9% to 76%. In an attempt to explain the disparity of results, we undertook a double-blind prospective study of the accuracy of duplex Doppler ultrasound in the detection of acute rejection in renal transplants. We scanned 49 consecutive patients with a total of 65 biopsies; 46 biopsies in 33 consecutive patients were included in our study. In our population, the prevalence of acute rejection was 61% (28/46). Using a resistive index (RI) cutoff of greater than 0.90 based on the main renal artery flow pattern, the sensitivity of our test was 43%, with a 67% specificity. The positive predictive value was 67%. Our results are contrasted and compared with the published data from other groups in a critical survey of the literature. We conclude that duplex Doppler sonography alone is inadequate to evaluate acute rejection in renal transplants.

False-negative duplex Doppler studies in children with hepatic artery thrombosis after liver transplantation

Recent reports describe formation of collateral vessels in children who have hepatic artery thrombosis after liver transplantation. This led us to reevaluate the role of duplex Doppler imaging in this population. Among 135 pediatric liver transplant patients, 20 had arteriography for suspected hepatic artery thrombosis. Duplex and/or color Doppler imaging was performed in 13 of these children. The Doppler examination failed to show hepatic artery signals in five patients. Arteriography showed hepatic artery thrombosis in all five. In three of these, subsequent Doppler examinations showed reappearance of arterial Doppler signals. Arteriography confirmed the interval development of collaterals. Hepatic artery signals were found on the Doppler examinations of the remaining eight patients. Four had normal arteriograms, but the remaining four had hepatic artery thrombosis with collateral formation. Patients with hepatic artery thrombosis and collateral circulation tended to have increased diastolic flow (decreased resistive index). In addition, early scans clearly identified patients with complete thrombosis before collateral formation. On the basis of our preliminary experience, a child with a liver transplant and a clinical history strongly suggestive of hepatic artery compromise should have arteriography despite an apparently normal Doppler examination.

Color Doppler imaging of portosystemic shunts

This study was designed to investigate the utility of color Doppler sonography in the evaluation of portosystemic shunts. Thirty-one patients with a total of 32 shunts were imaged. The types of shunts examined included portacaval, five; mesocaval, eight; distal splenorenal (Warren), 14; and mesoatrial, five. Sonography was performed without knowledge of the status of the shunt, although the type of shunt was known before beginning the study. The sonographic studies were evaluated to determine their sensitivity and specificity on the basis of a prospective comparison with angiography or MR imaging (22 cases). The possible advantages of color Doppler over duplex Doppler sonography in evaluating portosystemic shunts were also investigated, as was the ability of color Doppler sonography to image specifically the shunt anastomoses. Color Doppler sonography successfully inferred shunt patency (17 cases) or thrombosis (five cases) in all 22 shunts for which correlative imaging was available (sensitivity = 100%, specificity = 100%). In comparing duplex with color Doppler sonography in all 32 shunts, the two techniques were almost equally effective in establishing patency in portacaval, mesocaval, and mesoatrial shunts. Duplex Doppler sonography, however, provided useful diagnostic information in only four of 14 splenorenal shunts. Color Doppler correctly inferred patency or thrombosis in all 14. Among all 32 shunts, the anastomosis was shown clearly by color Doppler in 23, probably in four, and not all in five. Our results suggest that color Doppler sonography is an excellent method for the evaluation of all varieties of surgically created portosystemic shunts. In particular, color Doppler sonography appears to be superior to duplex Doppler sonography in imaging splenorenal communications.

Advances in medical imaging

The field of medical imaging, stimulated by advances in digital and communication technologies, has grown tremendously. New imaging techniques that reveal greater anatomical detail are available in most diagnostic radiology departments. We discuss vascular imaging with ultrasound, high-resolution computed tomography of the thorax, magnetic resonance imaging applications, and picture archiving and communication systems. Vascular imaging with ultrasound requires duplex and color flow Doppler, which combine gray-scale ultrasound and the Doppler phenomenon. High-resolution computed tomography modifies conventional computed tomography technology and results in images with higher spatial resolution. Magnetic resonance imaging applications for all areas of the body are being investigated and are replacing older roentgenographic techniques such as computed tomography, arthrography, myelography, and even angiography in a growing number of indications. With these new digital imaging modalities, image management has become an important consideration that can be addressed by picture archiving and communication systems.

Radiology: color Doppler ultrasonography of the liver

The Scientific Board of the California Medical Association presents the following inventory of items of progress in radiology. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established both as to scientific fact and important clinical significance. The items are presented in simple epitome and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, research workers, or scholars to stay abreast of these items of progress in radiology that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another.The items of progress listed below were selected by the Advisory Panel to the Section on Radiology of the California Medical Association, and the summaries were prepared under its direction.

Cranial arteriovenous malformations in neonates: color Doppler imaging with angiographic correlation

Five neonates with cranial arteriovenous malformations were studied with color Doppler sonography. Excellent correlation was found between sonography and subsequent angiography. In three patients with vein of Galen aneurysms, sonography showed a cystic structure with rapid or swirling flow. Careful adjustment of the color Doppler system was required to demonstrate flow in another patient with a dural arteriovenous malformation. An arteriovenous fistula in a fifth patient appeared as an area of increased flow. Arterial feeders and major draining veins were visualized in all five patients. Color Doppler imaging also was used to assess the effect of embolic or operative therapy in three of the patients. We conclude that color Doppler sonography is able reliably to characterize flow patterns in neonatal cranial arteriovenous malformations. Color Doppler imaging also is helpful in assessing flow after embolic or surgical therapy.

Endovaginal sonographic diagnosis of dilated fallopian tubes

Twelve cases of fallopian tube dilatation were diagnosed in 10 patient by using endovaginal sonography. The diagnosis was confirmed by surgery in seven patients and by hysterosalpingography in three. A tubular shape was present in every case. Other sonographic features included a well-defined echogenic wall, a folded configuration, and linear echoes protruding into the tube lumen. Dilated tubes were distinguished from bowel loops by a lack of peristaltic activity and from pelvic veins by a lack of moving low-level echoes on real-time sonography. We conclude that the findings of dilated fallopian tubes on endovaginal sonography are sufficiently characteristic to allow the diagnosis to be made with this technique.