Usefulness of three-dimensional sonography in procedures of ablation for liver cancers: initial experience.

OBJECTIVE: To investigate the usefulness of three-dimensional sonography in procedures of ablation for liver cancers. METHODS: Two- and three-dimensional sonography were used in guiding 18 chemical ablation procedures (7 with boiling carboplatin ablation and 11 with ethanol ablation) and 21 radio frequency ablation procedures for treatment of liver cancers. The applicator conspicuity depicted by the 2 imaging modalities, the confidence level of the operator in determining the position relationship between the applicator and the tumor using the 2 imaging modalities, and the alteration of ablation procedures were evaluated. RESULTS: Three-dimensional sonography was better than two-dimensional sonography in delineation of multitined, expandable electrode tips in radio frequency ablation procedures, whereas the 2 modalities were equal in depicting percutaneous transhepatic cholangiography needle tips in chemical ablation procedures. Three-dimensional sonography significantly enhanced the confidence level in defining the spatial relationship between applicator and tumor in comparison with two-dimensional sonography (P < .01). Suboptimal applicator placement was detected in 6 (15%) of 39 ablation procedures on three-dimensional sonography: 3 chemical ablation procedures and 3 radio frequency ablation procedures. Applicator adjustment was required in 3 chemical ablation procedures. In 15 (38%) of 39 procedures, three-dimensional sonography allowed better visualization of the position relationship between the applicator and adjacent critical structures. CONCLUSIONS: Three-dimensional sonography was useful in delineation of expandable radio frequency electrodes, improvement of operator confidence level, determination of applicator placement, and visualization of the position relationship between the applicator and adjacent critical structures during procedures of liver cancer ablation under image guidance.     

Sonographic findings in cases of missed gallstones

PURPOSE. We retrospectively evaluated sonographic findings in 946 cases of gallstones to determine whether the false-negative rate for gallstone detection by sonography has decreased as a result of technologic advances over the past 15 years. METHODS: We reviewed preoperative sonographic reports, operative notes, and pathologic reports for 614 women and 332 men (ages 22-78 years) seen over a 2.5-year period and compared sonographic findings with surgical pathologic findings after cholecystectomy. Sonograms for patients whose gallstones were missed on sonography were reviewed by 3 board-certified radiologists. RESULTS: Preoperative sonography of the gallbladder accurately predicted the presence of gallstones in 934 cases (98.7%). Gallstones were not identified by sonography in the remaining 12 cases. In those cases, sonography revealed polyps in 5, sludge in 5, sludge plus a polyp in 1, and neither stones nor polyps in 1. Thus, the false-negative rate was 1.3%. CONCLUSIONS: Despite improvements in sonographic technology, detection of small gallstones remains difficult in some cases. Adherent gallstones can mimic gallbladder polyps. Our false-negative rate for detection of gallstones was no different from that in earlier studies.     

Three-dimensional sonographic morphologic assessment in complex adnexal masses: preliminary experience.

OBJECTIVE: To evaluate the role of three-dimensional transvaginal sonography in assessing complex adnexal masses. METHODS: Forty-one women (mean age, 49.5 years; range, 23-75 years) with the diagnosis of complex adnexal masses on the basis of two-dimensional transvaginal sonography were reevaluated by three-dimensional transvaginal sonography. Two different sonologists evaluated the two- and three-dimensional transvaginal sonograms. Criteria indicative of malignancy included the presence of gross papillary projections, solid areas, and solid echogenicity for both techniques. Three women (7%) had bilateral masses, giving a total of 44 masses that were ultimately assessed. A definitive histologic diagnosis was obtained in every case after surgical tumor removal. RESULTS: Twenty-one tumors (47.7%) were proved malignant, and 23 (52.3%) were benign. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for two- and three-dimensional transvaginal sonography were 90%, 61%, 68%, 87%, and 75% and 100%, 78%, 81%, 100%, and 89%, respectively. There were no statistical differences between two- and three-dimensional transvaginal sonography (McNemar test, P = .687). The agreement between both examiners was high (kappa index = 0.71). CONCLUSIONS: The use of three-dimensional transvaginal sonography does not significantly improve the two-dimensional transvaginal sonographic morphologic assessment of complex adnexal masses; however, we found it useful for reinforcing initial diagnostic impressions.     

Preoperative evaluation of pelvic tumors by Doppler and three-dimensional sonography.

OBJECTIVE: To study a spectrum of systems (two-dimensional transvaginal, transvaginal color Doppler, three-dimensional, three-dimensional power Doppler, and contrast-enhanced three-dimensional power Doppler sonography) for preoperative evaluation of pelvic tumors. METHODS: Two hundred ninety-two patients were evaluated by the 5 complementary methods in preoperative sonographic assessments. We examined adnexal and endometrial morphology, thickness, and volume by two- and three-dimensional sonography and analyzed blood flow by transvaginal color, pulsed Doppler, and three-dimensional power Doppler sonography in all examined patients. In 89 patients with complex adnexal lesions of uncertain malignancy, contrast-enhanced three-dimensional power Doppler sonography was performed. RESULTS: Morphologic assessment by three-dimensional sonography yielded additional information in 58% of cases compared with two-dimensional sonography. Furthermore, this modality was superior to two-dimensional sonography in accurate depiction and diagnosis of 2 cases of fallopian tube carcinoma. Combined morphology and vascular indexing reached sensitivity of 97% and specificity of 99%. Endometrial volume in patients with malignant disease was significantly different (28.2 +/- 0.02 cm3) from that in those who had hyperplasia (7.81 +/- 0.03 cm3), polyps (3.5 +/- 0.02 cm3), or normal endometria (0.8 +/- 0.02 cm3). With combined morphologic and three-dimensional power Doppler examination of endometrial lesions, sensitivity and specificity reached 89% and 97%, respectively. CONCLUSIONS: Combined morphologic and vascular imaging improves preoperative assessment of gynecologic tumors.     

Prenatal diagnosis of Jeune-like syndromes with two-dimensional and three-dimensional sonography

The purpose of this article is to describe the use of three-dimensional sonography as an adjuvant to two-dimensional sonography facilitating an earlier and more definitive diagnosis of Jeune and Jeune-like syndromes in the second trimester. We report two cases in which three-dimensional sonography facilitated the diagnosis of these malformations. A diagnosis of Jeune syndrome was made in our first case. Our second case was found to be short-rib polydactyly syndrome Type IV. Three-dimensional skeletal survey visualized short ribs, short limbs, the presence of normal scapulae, and the absence of polydactyly in both cases. Three-dimensional sonography can assist two-dimensional sonography in providing a more accurate display of skeletal anomalies, limb abnormalities, and facial features.     

Three-dimensional sonographic evaluation of the common bile duct.

OBJECTIVE: To assess the accuracy of three-dimensional sonographic measurements of the common bile duct compared with standard two-dimensional anteroposterior measurement of the common duct. METHODS: Fifty-five consecutive patients referred for abdominal sonography underwent standard two-dimensional abdominal sonography followed by three-dimensional sonographic data acquisition of the right upper quadrant. A radiologist blinded to the results of the two-dimensional examination later measured the three-dimensional long axis anteroposterior common duct diameter and three-dimensional short axis anteroposterior and transverse common duct diameters. RESULTS: The mean average common duct diameter as measured by two-dimensional sonography (long axis anteroposterior) was 3.6 mm. The mean average common duct diameter as measured by long axis anteroposterior three-dimensional sonography was 4.1 mm. The mean average common duct diameter as measured by anteroposterior short axis three-dimensional sonography was 4.1 mm, and by transverse short axis three-dimensional sonography, it was 4.4 mm. The two-dimensional common duct measurement correlated with the long axis anteroposterior three-dimensional measurement (P < .001), the short axis anteroposterior three-dimensional measurement (P < .001), and the short axis transverse three-dimensional measurement (P < .005) by the Spearman rank order correlation coefficient test. CONCLUSIONS: Three-dimensional sonographic measurements of the common bile duct correlate highly with two-dimensional measurements, validating the use of three-dimensional sonography as a reliable method for evaluation of common bile duct size.     

Correlation between color power Doppler sonographic measurement of breast tumor vasculature and immunohistochemical analysis of microvessel density for the quantitation of angiogenesis.

OBJECTIVE: To record the correlation between color power Doppler sonographic measurement of breast tumor vasculature and immunohistochemical analysis of microvessel density for the quantitation of angiogenesis. METHODS: Women with palpable breast masses scheduled for excision biopsy were scanned with two- and three-dimensional color power Doppler sonography before and after the administration of a sonographic contrast agent. Vessel counts were performed on two- and three-dimensional sonographic images before and after contrast agent administration. All tumors were surgically removed and underwent immunohistochemical analysis for microvessel density assessment. The sonographic measure of tumor vascularity was correlated with microvessel density. RESULTS: Pathologic examination showed 43 breast cancers and 14 benign breast masses. Higher microvessel density was noted in malignant than benign breast masses (P < .0005). Color power Doppler sonographic measurement of tumor vessel number showed a significant positive correlation with tumor size (P < .05) and progesterone receptor negativity (P < .05). A significant positive correlation was observed between microvessel density and the number of intratumoral blood vessels assessed by both two- and three-dimensional color power Doppler sonography (P < .05). Regression models showed three-dimensional color power Doppler sonography to have a significantly higher correlation with microvessel density when compared with two-dimensional color power Doppler sonography at baseline (P < .005). The administration of a sonographic contrast agent did not improve correlation with microvessel density. CONCLUSIONS: A significant correlation was shown between color power Doppler sonographic measurement of tumor vascularity and microvessel density by immunohistochemical analysis. Further improvement in Doppler sonographic techniques to map capillary vessel flow should be explored to improve the current association with pathologic findings.     

Three-dimensional gray scale volume rendering of the liver: preliminary clinical experience.

OBJECTIVE: To investigate the potential clinical usefulness of three-dimensional gray scale volume rendering in the liver. METHODS: Sixty-two patients were enrolled in the study and categorized into 2 groups: group I with ascites and group II without. Two types of volume-rendering modes, i.e., surface and transparent, were used to obtain the three-dimensional images. The data were reviewed to identify the differences between two- and three-dimensional images of the liver in each subject. RESULTS: In group I, three-dimensional sonography was superior to two-dimensional sonography in terms of surface features, edges, overall three-dimensional impression, image clarity, and structural relationships. However, it seemed that three-dimensional sonography in the surface mode was inferior to two-dimensional sonography in showing intrahepatic structures, because it had decreased resolution. In group II, three-dimensional sonography was superior to two-dimensional sonography with respect to the continuity of intrahepatic vessels, overall three-dimensional impression of the vessels, image clarity, and the relationship between lesions and neighboring vessels. However, the resolution of the lesions was decreased in 7 cases of hepatocellular carcinoma. CONCLUSIONS: Our experience suggests that three-dimensional gray scale volume rendering of the liver provides more diagnostic information than two-dimensional sonography; however, further studies are needed to evaluate its clinical importance.     

Three-dimensional color Doppler sonography and uterine artery arteriography of fibroids: assessment of changes in vascularity before and after embolization.

OBJECTIVE: To assess the accuracy of three-dimensional color Doppler sonography and uterine artery arteriography in depicting changes in fibroid vascularity before and after embolization. METHODS: Preembolization and postembolization three-dimensional color Doppler sonography and selective uterine artery arteriography were retrospectively compared in 15 patients who underwent uterine artery embolization for treatment of symptomatic fibroids. Three-dimensional color Doppler sonography was performed by using a scanner with color power angiographic imaging capability. Vascularity was quantified by using an estimation of power-weighted pixel density as described by our group in previously published studies. Uterine artery arteriography was performed by using a standard selective microcatheter embolization technique. For purposes of comparison, fibroids were classified as either hypervascular or hypovascular relative to myometrial vascularity before and minutes to several hours after uterine artery embolization. Changes in fibroid vascularity (i.e., from hypervascular to hypovascular) as depicted by three-dimensional color Doppler sonography were compared with those shown on uterine artery arteriography and classified as being in agreement or disagreement. RESULTS: In 13 (87%) of 15 patients there was agreement; in 2 (13%) of 15 there was disagreement. In both cases of disagreement, three-dimensional color Doppler sonography showed collateral flow not depicted by uterine artery arteriography The mean reduction in quantitated vascularity after uterine artery embolization was 44% (range, 19%-78%). CONCLUSIONS: Three-dimensional color Doppler sonography accurately depicts fibroid vascularity and in some cases can reveal collateral flow not depicted by uterine artery arteriography.     

Sonographic diagnosis of urethral anomalies in infants: value of perineal sonography.

OBJECTIVE: To assess the value of urethral sonography including a perineal approach in evaluating urethral anomalies in infants. METHODS: A radiology database review identified 88 patients (mean age +/- SD, 64 +/- 84 days) who underwent voiding cystourethrography (VCUG) and urethral sonography as part of extended sonography of the urinary tract. Sonographic and VCUG images and reports were reviewed to assess agreement between both modalities for detection of urethral anomalies. RESULTS: Sonography facilitated the correct diagnosis of all 3 posterior urethral valves. The only urethral diverticulum, the only ectopic ureteric insertion into the urethra, the only urogenital sinus, and the only urethrovaginal fistula were also shown on sonography. In 73 (94%) of 78 cases, sonography correctly showed the absence of anomalies. In 5 infants, sonography could not reliably assess the urethra and showed indirect signs of urethral anomalies; however, these patients had normal urethras on VCUG. CONCLUSIONS: Our data show that sonography of the urethra is a valuable tool for diagnosis of urethral anomalies. Especially, negative findings on sonography are highly suggestive of the absence of urethral anomalies. Positive or equivocal sonographic findings should indicate VCUG.     

三维超声在胆道疾病诊断中的应用价值

目的评估三维超声在胆道疾病诊断中的应用价值。方法对91例胆道疾病的患者首先应用二维超声进行图像采集,然后应用三维超声进行图像重建。结果三维超声可清晰、直观显示胆囊结石、胆管结石形状、数目、位置;可直观显示胆囊息肉样病变病灶部位和表面特征,准确评价胆囊息肉是否带蒂及胆囊腺瘤基底部的宽窄;还可清晰显示胆囊癌、胆管癌病灶范围、胆囊壁连续性以及肿瘤病灶浸润周围脏器的程度;可清楚显示胆管结石与胆管壁的关系;可形象、直观地显示胆管壁受累程度及病灶位置、生长方式、是否浸润周围组织。本组胆道疾病患者三维超声诊断符合率为90.1%(82/91),高于二维超声诊断符合率76.9%(70/91),且差异有统计学意义(χ2=5.747,P<0.05)。结论三维超声可更直观地显示胆道疾病病灶的形态特点及其与周围组织脏器的关系,能提供较二维超声更丰富的信息,对明确诊断及确定治疗方案有重要的临床意义。     

Three-dimensional power Doppler imaging in depicting vascularity in hepatocellular carcinoma.

OBJECTIVE: To assess the ability of three-dimensional power Doppler imaging to depict vascularity in hepatocellular carcinoma. METHODS: Forty-three patients with hepatocellular carcinomas were subjected to two- and three-dimensional power Doppler imaging, and 14 of them also underwent angiography. The delineated amounts of intratumoral Doppler signals were compared between 2 methods of power Doppler imaging in 43 patients. In the 14 patients who also underwent angiography, the patterns of blood supply depicted by 2 methods of power Doppler imaging were compared with that depicted by angiography, and the intratumoral vascularity on three-dimensional projection images and angiograms was also quantitatively assessed by calculating the vascularity-area ratio with graphics software. RESULTS: In comparison with two-dimensional power Doppler imaging, three-dimensional power Doppler imaging was subjectively determined as showing more intratumoral Doppler signals in 32 (74.4%) of the 43 lesions. The accuracies in depicting vascular patterns were 64.3% (9 of 14) for three-dimensional projection images and 14.3% (2 of 14) for two-dimensional slices compared with the results of angiography. The vascularity-area ratios on three-dimensional power Doppler imaging projections and angiograms were 46.0% +/- 25.6% and 48.5% +/- 22.5% (mean +/- SD), respectively (P > .05). Three-dimensional projection images correlated significantly with angiograms in quantifying the vascularity (gamma = 0.87; P < .001). CONCLUSIONS: A three-dimensional power Doppler projection image gives a better overall picture of vascular distribution than a two-dimensional slice and correlates with angiography significantly for delineating vascularity in hepatocellular carcinoma.     

Contrast-enhanced two- and three-dimensional sonography for evaluation of intra-abdominal hemorrhage.

OBJECTIVE: To determine whether a contrast agent enhances sonographic detection of bleeding sites in the abdomen and whether contrast-enhanced three-dimensional sonography provides additional information compared with contrast-enhanced two-dimensional sonography. METHODS: Bleeding sites were created within the livers (n = 3), spleens (n = 5), and kidneys (n = 3) of 3 dogs. A sonographic contrast agent with vascular and parenchymal enhancement capabilities was administered intravenously at a dose of 0.02 mL/kg. Before and after each contrast agent injection, the bleeding sites were imaged with two- and three-dimensional sonography in gray scale harmonic imaging and color flow modes. Sonographic findings were compared with gross pathologic findings. RESULTS: Noncontrast-enhanced sonography was not able to show the specific location of the active bleeding in any of the organs evaluated. The contrast agent enhanced the sonographic detection of blood flow in normal vessels and extravasated blood from damaged vessels or organs in all cases. Intrasplenic and intrahepatic hematomas were better identified on delayed imaging sequences because there was marked enhancement of the normal parenchyma, whereas the hematomas remained unenhanced. Reconstructed three-dimensional sonography showed spatial relationships of the bleeding sites and surrounding structures. Gross pathologic findings were consistent with the contrast-enhanced sonographic results. CONCLUSIONS: Contrast-enhanced sonography improves the detection and evaluation of abdominal bleeding sites. Contrast-enhanced three-dimensional sonography appears to provide additional information when compared with two-dimensional sonography.     

Adnexal torsion: new clinical and imaging observations by sonography, computed tomography, and magnetic resonance imaging.

OBJECTIVE: The purpose of this study was to review the clinical, imaging, and pathologic findings associated with adnexal torsion. METHODS: A review of surgically proven cases of torsion between 1990 and 2006 included clinical, surgical, and pathologic data and preoperative sonographic, computed tomographic (CT), and magnetic resonance imaging (MRI) studies. Imaging reports were assessed to determine whether a correct preoperative diagnosis was made. Factors related to failure to make a correct diagnosis were evaluated. RESULTS: Fifty-eight cases of torsion were evaluated (patient ages, 12-85 years; 14 postmenopausal). There was a slight right-sided predominance (55%); in most cases (72%), both the ovary and fallopian tube were involved. Common symptoms/signs were pain (91%), leukocytosis (64%), nausea/vomiting (62%), and a palpable mass (41%). Twenty-eight patients (48%) had previous abdominal surgery; in 12 (46%) of these 28, pelvic adhesions were noted. At pathologic examination, underlying adnexal masses were found in 30 cases (52%); they were benign in 26 (87%) of 30 cases. Common imaging findings were an adnexal mass (65% on sonography, 87% on CT, and 75% on MRI), a displaced adnexal mass/enlarged ovary (53% on sonography, 87% on CT, and 75% on MRI), and ascites (53% on sonography, 73% on CT, and 50% on MRI). A correct preoperative diagnosis was made by initial sonography in 15 (71%) of 21 cases versus initial CT in 5 (38%) of 13. A correct imaging diagnosis was made more frequently in premenopausal than in menopausal patients (P = .02) and in patients without an underlying adnexal mass compared with those with a mass (P = .05). CONCLUSIONS: Although CT shows features suggestive of torsion, in our study, the diagnostic value of initial CT was less than that of initial sonography. A correct preoperative diagnosis was made less often with an underlying adnexal mass and in postmenopausal women. Previous surgery and adhesions may be predisposing factors for adnexal torsion.     

经会阴超声在宫颈良性病变诊断中的应用

目的 评价经会阴超声在宫颈良性病变诊断中的应用价值。方法 43例不同原因子宫全切术患者，术前经会阴进行超声检查，检查结果与术后病理结果对照。结果 经会阴超声检查宫颈良性病变，最常见的是宫颈囊肿19例；宫颈肌瘤11例；宫颈息肉8例；慢性宫颈炎5例。病理结果：宫颈囊肿19例；宫颈肌瘤9例；宫颈息肉9例；慢性宫颈炎6例。诊断符合率分别为100％、85％、92％、80％。结论 经会阴超声诊断宫颈良性病变特异性较强、敏感性高，可为临床提供较可靠的诊断依据。     

Three-dimensional ultrasonography of normal fetal heart: comparison with two-dimensional imaging.

Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three-dimensional ultrasonography to compare two-dimensional and non-cardiac-gated three-dimensional ultrasonography of the normal fetal heart. After normal two-dimensional studies, three-dimensional sonographic volumes were acquired without cardiac gating in transverse and longitudinal planes. Standard cardiac views were derived from three-dimensional data, analyzed, and rated as follows: (1) not identifiable, (2) identifiable but inadequate for diagnosis, (3) adequate, and (4) excellent. Two-dimensional ultrasonography demonstrated better yields of diagnostically acceptable images of basic echocardiographic views (four-chamber view, 100% for two-dimensional sonography versus 10 to 71% for three-dimensional sonography; right ventricular outflow tract, 42% for two-dimensional versus 6 to 26% for three-dimensional ultrasonography; left ventricular outflow tract, 71% for two-dimensional versus 13 to 45% for three-dimensional sonography). In one subject three-dimensional ultrasonography was superior to two-dimensional sonography in demonstrating an outflow tract. Aortic and ductal arches were not imaged with the two-dimensional technique but were available from the acquired three-dimensional volumes in 3 to 32% and 23%, respectively. False-positive and false-negative findings were observed on three-dimensional ultrasonograms. Overall, compared to two-dimensional ultrasonography, non-cardiac-gated three-dimensional sonography yielded inadequate reconstructed image quality of basic echocardiographic views (four-chamber view, right ventricular outflow tract, left ventricular outflow tract). Three-dimensional ultrasonography, however, shows potential for allowing nonechocardiographers to acquire some diagnostically acceptable views of the aortic and ductal arches.     

Transvaginal color Doppler sonography versus sonohysterography in the diagnosis of endometrial polyps.

OBJECTIVE: To compare the diagnostic performance of transvaginal color Doppler sonography (TVCD) and sonohysterography (SHG) in the diagnosis of endometrial polyps. METHODS: Fifty-one women (mean age, 51 years; range, 27-75 years) with clinical or B-mode sonographic suspicion of endometrial polyps were included in this prospective study. Transvaginal color Doppler sonography first and then SHG were performed in all patients. On TVCD, a polyp was suspected when a vascular pedicle penetrating the endometrium from the myometrium was identified. On SHG, a polyp was suspected when a focal polypoid lesion was seen within the endometrial cavity. All patients underwent hysteroscopy and endometrial biopsy, the findings of which were used as the criterion standard. Sensitivity and specificity for TVCD and SHG were calculated and compared by the McNemar test. RESULTS: Hysteroscopy and endometrial biopsy findings were as follows: endometrial polyps, 41; endometrial hyperplasia, 3; cystic atrophy, 4; proliferative endometrium, 2; and endometritis, 1. Sensitivity and specificity for TVCD and SHG were 95% and 80% and 100% and 80%, respectively (McNemar test, P = .5) CONCLUSIONS: Transvaginal color Doppler sonography and SHG had similar performance for diagnosing endometrial polyps.     

Three-dimensional ultrasonographic imaging of the neonatal brain in high-risk neonates: preliminary study.

The aim of this investigation was to compare the utility of three-dimensional ultrasonography versus two-dimensional ultrasonography in imaging the neonatal brain. Thirty patients in the neonatal intensive care unit underwent two-dimensional and three-dimensional ultrasonography. The resultant two- and three-dimensional images recorded on film and three-dimensional volumes (reviewed on a workstation) were evaluated independently. Comparable numbers of normal and abnormal studies were diagnosed by each modality. Axial images were considered useful in approximately 50% of three-dimensional cases. Image quality, overall and in the far-field, was rated higher on two-dimensional images. Three-dimensional sonographic acquisition time in the neonatal intensive care unit (1.7 min+/-0.7 standard deviation) was significantly shorter than that for two-dimensional sonography (9.0+/-4.5 min). The total time for evaluation on the three-dimensional workstation (4.4+/-1.1 min) was significantly less than that for two-dimensional images on film (10.6+/-4.7 min). In conclusion, three-dimensional ultrasonography is a promising, diagnostically accurate, and efficient imaging tool for evaluation of the neonatal brain; however, visualization must improve before it can replace two-dimensional ultrasonography.     

Application of three-dimensional ultrasonography in the evaluation of the fetal heart.

The objectives of this study were to determine whether three-dimensional ultrasonography can provide more cardiac views than two-dimensional ultrasonography and to develop a standard technique. Eighteen women, 16 to 26 weeks' gestation, were scanned with two-dimensional ultrasonography for 10 minutes or less to obtain fetal heart views. Three-dimensional ultrasonography was used (< or =10 minutes) to obtain up to 4 acquisitions of the fetal heart: 4-chamber view, left parasagittal, transverse, and longitudinal nonstandard. Views were later extracted from saved volume data, comparing the yields of two- and three-dimensional ultrasonography. The 4-chamber view was obtained in 15 (93%) of 16 cases on both two- and three-dimensional ultrasonography. On two-dimensional ultrasonography, the left outflow tract was obtained in 68% of the cases; on three-dimensional ultrasonography, the left outflow tract was obtained in 46% from the 4-chamber view acquisition and in 100% from the left parasagittal acquisition. On two-dimensional ultrasonography, the right outflow tract was obtained in 68% of the cases; on three-dimensional ultrasonography, the right outflow tract was obtained in 86% from the 4-chamber view acquisition and in 71% from the left parasagittal acquisition. Aortic and ductal arches were obtained in 12% and 18%, respectively, on two-dimensional ultrasonography. On three-dimensional ultrasonography the aortic and ductal arches were obtained in 66% and 86%, respectively, from the 4-chamber view acquisition and in 57% and 71%, respectively, from the left parasagittal acquisition. Three-dimensional ultrasonography permitted a greater number of cardiac views to be extracted from volume data than did two-dimensional ultrasonography.     

Three-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord: value and limitations.

OBJECTIVE: The purpose of this study was to examine the value of 3-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord. METHODS: Cases in which the diagnosis of a true knot of the umbilical cord was suspected by prenatal 2-dimensional sonography were reviewed. The presumably affected segment of the cord was examined with 3-dimensional power Doppler sonography for further characterization. Confirmation of the prenatal diagnosis was sought by reviewing the delivery records and contacting the referring obstetrician and the patients themselves. RESULTS: Eight consecutive cases were studied. Three-dimensional power Doppler sonography displayed a vascular spatial configuration pattern consistent with a true knot of the umbilical cord in all of them. However, the prenatal diagnosis was confirmed at delivery in only 5 cases (62.5%). Although there were no cases of a false knot mimicking a true knot of the umbilical cord, all incorrect diagnoses in this series were associated with multiple loops of the umbilical cord in the third trimester. CONCLUSIONS: Three-dimensional power Doppler sonography seems to be helpful in determining the presence of a true knot of the umbilical cord in utero, especially in the second trimester. However, this should not be considered a definitive method for the diagnosis because multiple loops of the umbilical cord lying close to each other can generate a sonographic image that can be undistinguishable from a true knot of the umbilical cord prenatally, especially when located in a small pocket of amniotic fluid. Therefore, the presumable diagnosis of a true knot of the umbilical cord in utero should be taken with caution.