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Objective To evaluate the feasibility and accuracy of fetal gender assignment from three-dimensional ultrasound (3D US) data at 10–24 weeks' gestation. Methods Three-dimensional ultrasound volume data on 47 fetuses were reviewed and divided into groups: 10–14, 15–18, and 19–24 weeks. Fetal genitalia were studied in axial and sagittal planes for gender assignment, using published criteria. The most valuable plane for assignment was noted. Gender assignment was compared with gender at birth. Results Gender assignment was possible in 44 of 47 fetuses; 25 assigned male and 19 female. Between 10 and 14 weeks the mid-sagittal plane alone was diagnostic for all fetuses. Accuracy of assignment between 11 and 14 weeks was 100%. Between 15 and 18 and 19 to 24 weeks, male assignment was 100% accurate. Female assignment was 100% accurate between 15 and 18 weeks. Accuracy decreased to 60% in the 19 to 24 week group, however, in two of the five cases in which gender was wrongly assigned to be male, the assignment was prospectively considered doubtful due to poor resolution of volume data. Excluding these two cases, accuracy for female assignment in the 19–24 week group was 100%. Conclusion Using 3D US, gender assignment was possible in 44 of 47 of fetuses, as early as 11 weeks' gestation. In early gestation, 11–14 weeks, accuracy of male and female gender assignment was 100%. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology

After Wilhelm Conrad Roentgen's discovery of the X-ray in 1895, it was initially thought that gallstones could not be visualized. Surgeons relied solely on the clinical examination to detect biliary disease. Today, no evaluation of the gallbladder would be complete without the performance of an imaging study. Radiology has gone through several eras in the imaging of gallstones. The plain film era, 1895-1924, was characterized by techniques that improved soft-tissue detail, allowing better detection of radiopaque stones. The contrast media era, 1924-1960, was initiated by the invention of IV cholecystography. In 1925, oral cholecystography was developed. During the era of expanding technology, 1960-1979, percutaneous transhepatic cholangiography, scintigraphy, and sonography came into use. The therapeutic era began in the 1980s.

The purpose of this study was to describe the sonographic appearances of melanoma metastases of the skin, subcutaneous tissues, and superficial lymph nodes.Gray-scale sonography was performed on 31 superficial melanoma metastases in 18 patients. Discreteness of borders, contours, echogenicity, echotexture, and degree of acoustic through-transmission were evaluated for each lesion. Color Doppler sonography was also performed on 25 of the 31 lesions, by which the amount of internal color flow was qualitatively assessed.Twenty-eight (90%) of the 31 metastases had well-defined borders. Contours were smooth in 17 (55%), lobulated in 12 (39%), and spiculated in two (6%). Nineteen metastases (61%) were hypoechoic to muscle, 10 (32%) were isoechoic, and two (6%) were hyperechoic. Echotexture was homogeneous in six lesions (19%), mildly heterogeneous in 13 (42%), moderately heterogeneous in 11 (35%), and markedly heterogeneous in one (3%). Twenty-two lesions (71%) showed enhanced acoustic through-transmission. Of the 25 melanoma metastases for which we performed color Doppler sonography, 18 (72%) had internal arterial color flow and seven (28%) did not. The flow was characterized as mild in 13 (72%) of 18, moderate in four (22%), and marked in one (6%).On sonography, superficial melanoma metastases typically are well-defined hypoechoic lesions with smooth or lobulated contours, mild to moderate heterogeneity, and enhanced acoustic through-transmission. Internal flow revealed by color Doppler sonography is present in many, but not all, superficial melanoma metastases.

Recent reports have indicated that identification of the yolk sac should precede the detection of the embryo in a normal first-trimester sonographic examination and that failure to visualize a yolk sac strongly suggests an abnormal intrauterine pregnancy. A first-trimester prospective study was performed in 163 normal and 49 abnormal consecutive singleton gestations. All women were examined both abdominally and transvaginally, with pregnancy outcome determined by delivery of a normal infant or a spontaneous abortion. The yolk sac was analyzed in all patients in whom an embryo was not identified (n = 76). When the yolk sac was identified, the following was found: by the abdominal approach with the mean sac diameter (MSD) less than 27 mm (n = 15), nine gestations were normal and six were abnormal, and by the transvaginal approach with the MSD less than 18 mm (n = 13), seven gestations were normal and six were abnormal. The presence of a yolk sac was not consistently predictive of a normal early pregnancy. When the yolk sac was also not identified, the following was found: abdominally with the MSD less than 27 mm (n = 41), 19 gestations were normal and 22 were abnormal, and transvaginally with the MSD less than 18 mm (n = 11), six gestations were normal and five were abnormal. Absence of the yolk sac was not consistently predictive of a spontaneous abortion. When using the MSD range (20-27 mm abdominally and 7-16 mm transvaginally), over which the yolk sac but not the embryo should be identified sonographically, the yolk sac was again not consistently visualized. On abdominal sonograms, the yolk sac was present and absent in three and 10 patients, respectively, for both normal and abnormal pregnancies. On transvaginal sonograms, the yolk sac was present and absent in seven and five normal gestations and in six and four abnormal gestations, respectively. The results of this study suggest that detection of the yolk sac in the first trimester is not an early predictor of pregnancy outcome.

Endoluminal sonography of the urinary tract was performed by using endoluminal ultrasound transducers contained within 2-mm-diameter catheters. The catheters were inserted into the urinary bladder via the urethra and advanced into the ureters and renal pelvis under cystoscopic control; then, cross-sectional images of the bladder, ureters, and renal pelvis were obtained. Two dogs and seven human patients were studied. In one dog, a 4.5-mm pseudopolyp, which was surgically created in the bladder wall, was successfully imaged; in the other, stones 2 mm or larger inserted into the bladder were identified. Of the seven patients, sonography showed stones embedded in the renal parenchyma (one patient) and the mucosa of the distal ureter (one patient). These were ultimately confirmed by their eventual removal. In a third, sonography showed a tumor of the distal ureter and identified the depth of the tumor. This was confirmed by biopsy. In a fourth, sonography clearly showed a crossing vessel as the cause for narrowing of the proximal ureter. In a fifth, sonography showed that the cause of a ureteral stricture was idiopathic. In the last two cases, sonography did not reveal a cause for hematuria. In these last three cases, negative sonographic results were confirmed by direct ureteroscopic examinations and follow-up studies. Our observations based on this limited study suggest that endoluminal sonography is a useful procedure for diagnosing diseases of the urinary tract. Further study is warranted.

Sonograms of 110 patients were compared to recently performed liver biopsies for evaluation of the accuracy of sonography in predicting the type (pattern) of pathology and its grade of severity (mild, moderate, or severe) in a wide variety of diffuse liver processes. There are two distinct, abnormal sonographic patterns: the fatty-fibrotic pattern seen primarily with cirrhosis, chronic hepatitis, and/or fatty infiltration, and the centrilobular pattern seen primarily with acute hepatitis. Sonography was 88% accurate in assigning the correct pattern to the corresponding pathology (sensitivity 89%, specificity 86%, p less than 0.001). The degree of accuracy was dependent on the grade of pathologic severity, with mild disease offering the greatest difficulty; moderate and severe diseases were accurately detected and placed in the correct pattern in all cases. Sonographic grading of the severity of disease was far less precise (63% overall). This study showed that sonography can distinguish between two abnormal sonographic patterns of diffuse benign liver disease as well as between normal and abnormal patterns.

Information on streaming potentials in large bore tubing in the turbulent flow regime is presented. Electrolytes used were aqueous solutions of sodium chloride, cupric chloride, and cupric sulphate. Correlations have been developed extending the classical relationship, E ΔP = constant (usually confined to regions of laminar flow), into the turbulent flow regime (Re ≈ 14 000). A correlation between streaming potential and temperature is also presented.

Both sonography and fluoroscopy have been recommended for renal localization and needle guidance for percutaneous nephrostomy. The respective efficacies of both methods have been compared in a prospective study of 88 patients undergoing percutaneous nephrostomy by the catheter over guide wire technique. Fifty-five patients had initial puncture using either an A-mode (42 patients) or real time (13 patients) sonographic aspiration transducer, while 33 patients had a single plane vertical beam fluoroscopy for puncture guidance. The use of either sonographic method for the initial needle puncture significantly reduced the number of puncture attempts (p = 0.000004) and potential iatrogenic risk, eliminated the need for intravenous administration of contrast material, allowed initial safe introduction of a large caliber needle, and decreased the length of time needed to perform the procedure.

Transperineal prostate biopsy performed with continuous sonographic monitoring by a real-time rectal endoscopic probe, using a longitudinal linear array which offered complete visualization of the needle from the perineum into suspected abnormal areas within the prostate, was performed in 25 patients with clinically suspected prostate disease. Clinically suspected nodules in 13 patients were more accurately biopsied using sonographic guidance as opposed to conventional manual, digital guidance. Subclinical carcinomas in three patients and areas of atypical histology in three patients were also identified and biopsied using transrectal sonographic guidance.

Three patients with clinically suspected pseudoaneurysm as a complication of femoral puncture were referred for ultrasound (US) evaluation with both conventional duplex Doppler US and color Doppler imaging. Pseudoaneurysm (n = 2) and simple hematoma (n = 2) were depicted with both Doppler systems, and a separate pseudoaneurysm and a hematoma were found in one patient. These diagnoses were confirmed surgically. Distinctive Doppler spectral waveforms and color Doppler findings enabled confident diagnoses. Color Doppler imaging allowed faster detection of intraaneurysmal flow, and the track between the injured artery and the pseudoaneurysm was identified only with color Doppler imaging. Duplex Doppler US with color Doppler imaging allows for the rapid, unequivocal diagnosis of pseudoaneurysm, thus enabling prompt treatment without the need for invasive diagnostic modalities.