Three-dimensional US of the fetus: volume imaging

PURPOSE: To retrospectively compare the rapidity, efficiency, and accuracy of three-dimensional (3D) and two-dimensional (2D) ultrasonography (US) for complete anatomic survey in fetuses at 17-21 weeks of gestation. MATERIALS AND METHODS: Institutional review board approval was obtained, informed consent was waived, and the study was HIPAA compliant. Fifty consecutive women undergoing fetal anatomic survey at 17-21 weeks of gestation formed the study cohort. After standard 2D US was performed by one of eight sonographers, the same sonographer also obtained five 3D volumes to encompass the entire fetal anatomy. Three physicians interpreting the scans independently evaluated the completeness of the examination and time needed to read the scans, comparing the standard 2D method with the 3D volume reconstruction technique. The paired t test was used to compare biparietal diameter (BPD), femur length, and performance times between the 3D measurements and the 2D measurement. The t test was used to compare fetal anatomy according to volume angle. Differences were significant when P < .05. RESULTS: Mean time to perform 2D US was 19.6 minutes per examination, whereas mean time to perform complete 3D volume acquisition was 1.8 minutes. Mean times needed to interpret 3D images and measure the BPD and femur were 5.53, 4.79, and 5.34 minutes for the three interpreting physicians. Compared with complete fetal surveys performed with 2D US, individual fetal anatomic landmarks (except for fetal arms and cavum septum pellucidum) were identified more than 94% of the time by using 3D US. Grouping anatomic views by region, the heart, head, extremities, and abdominal views were completely seen in 88%, 90%, 90%, and 95% of patients, respectively. No significant difference was seen between the three physicians regarding completeness of the 3D examinations (P = .7). One fetus had multiple anomalies, with 3D volumes identified as abnormal by all three physicians. Overall, 74% of 3D BPD measurements were within 1 mm of the 2D measurements, and 64% of 3D femur measurements were within 1 mm of the 2D measurements. CONCLUSION: The standard fetal anatomic survey can be performed in less than 2 minutes with 3D volume US, and the volumes can be interpreted in 6-7 minutes, compared with a mean of 19.6 minutes to perform standard 2D US.     

Osteomyelitis: detection with US. Work in progress

Ten patients with clinically suspected osteomyelitis were studied with ultrasound (US). Five patients had abnormalities detectable on sonograms. An abnormal fluid collection was demonstrated adjacent to the bone in three of these five. US-guided aspiration of the fluid in two of the three patients revealed purulent or infected fluid that was thought to represent an inflammatory exudate dissecting in a subperiosteal or extraperiosteal location. Findings from subsequent radiographic and scintigraphic studies confirmed the diagnosis of osteomyelitis in these three patients. The other two patients with abnormal sonographic results had collections of fluid that were separated from the bone by a variable amount of soft tissue. These collections were confined to the soft tissue and did not appear to arise from the bone. Aspiration revealed a soft-tissue abscess in one patient and a seroma in the second. Findings in this preliminary study suggest that fluid around the bone seen on sonograms may indicate acute osteomyelitis.     

Frequency-demodulated US: evaluation in the liver. Work in progress

Frequency modulated (FM) imaging is a new ultrasound (US) modality that uses pulse-echo signal instantaneous frequency in addition to the conventional envelope information. Eight features of the FM image in nondiseased livers are described. The technique is evaluated in a study of 34 patients with biopsy-proved diffuse liver disease. Visual grading of FM US image features shows good correlation with levels of biopsy-graded hepatic fibrosis. Patients with diffuse parenchymal liver disease often exhibit evidence of the abnormality when FM liver imaging is used, while such evidence is not as well demonstrated with conventional envelope (AM) imaging.     

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.     

Breast lesion characterization with contrast-enhanced US. Work in progress

PURPOSE: To characterise breast lesions on the basis of microcirculation features detected with contrast-enhanced US. MATERIALS AND METHODS: Thirty-six patients aged 42-63 years (mean age 55 years) with a single breast lesion previously detected at standard mammography were studied. All US examinations were performed using an ATL HDI 5000 ultrasound device with a 5-10 MHz linear-array transducer, before and after administration of ultrasound contrast medium Levovist (Schering(R), Berlin) was administered by bolus injection (2 ml/s) via a 20 G catheter probe. The mechanical index was set to high to obtain instant rupture of the microbubbles under insonation. Intensity/time curves of the transient scattering in the region of interest (ROI) after contrast administration were extrapolated. The areas under the ROI curves were also evaluated to quantitatively assess the scattering. RESULTS: The US baseline study and colour Doppler US identified 19 benign lesions (15 histologically proven) and 17 malignant lesions (16 histologically proven). The administration of contrast medium did not improve the specificity of the examination. Only by plotting the intensity/time curves of the regions of interest (ROI) and evaluating the areas under the ROI curves, was a significant correlation detected between US and histopathologic diagnosis. CONCLUSIONS: Although further evaluation on a larger series is needed, the analysis of breast lesions by contrast-enhanced perfusion US seems to be a promising technique. Perfusion US can usefully complement high-frequency US, especially when mammography is inconclusive.     

Absolute flow measurements using pulsed Doppler US. Work in progress

Quantitative flow measurements were assessed in both laboratory and canine models using pulsed Doppler ultrasonography (US). A hydrodynamic model consisting of a Harvard pulsatile pump, a water bath, tubing, and a variable resistance reservoir was used to obtain absolute volumetric flow measurements. Parameters including angle of incidence, size of tubing, stroke volume, stroke rate, sample volume, and transducer frequency were changed independently. The effect of varying these parameters on the determination of absolute flow was analyzed. Absolute flow measurements using duplex US were performed in the canine aorta and femoral artery with reference to the electromagnetic flow probe. These data are presented, along with methods to reduce error in flow measurements that can be directly applied to quantitative estimates of blood flow in humans.     

Achilles tendon: US diagnosis of pathologic conditions. Work in progress

Twenty-three patients were prospectively examined with ultrasound (US) for acute or recurrent Achilles tendon symptoms. Three types of pathologic conditions of the Achilles tendon were found: tendinitis/tenosynovitis, acute tendon trauma, and postoperative changes. US appears to enable differentiation of these conditions and to contribute to the diagnosis of a broad range of Achilles tendon disorders.     

Midgut volvulus in infants: diagnosis with US. Work in progress

The authors present findings from ultrasound (US) studies that can alert sonologists to the possibility of midgut malrotation complicated by volvulus in neonates and infants. A fluid-filled, distended duodenum seen at US examination in infants is a nonspecific sign of duodenal obstruction, as well as one of the signs of midgut malrotation. In addition, dilated, thick-walled bowel loops, mainly to the right of the spine, and peritoneal fluid were found at abdominal US examinations of three infants with midgut malrotation complicated by volvulus. In one infant with uncomplicated midgut malrotation, only signs of duodenal obstruction were present. The findings at US of duodenal obstruction associated with thickened bowel loops to the right of the spine and peritoneal fluid should lead the sonologist to suspect midgut malrotation complicated by volvulus, a potentially fatal condition, and an upper gastrointestinal series should then be performed to confirm the diagnosis.     

Parotid gland: US findings in Sj?gren syndrome. Work in progress

To determine the value of sonography of the parotid gland in patients with Sj?gren syndrome, six consecutive cases were retrospectively reviewed in which clinical findings indicated Sj?gren syndrome. All patients were women. Two patients were found at sonography to have normal parotid glands. Four patients had multiple cystic changes in the parotid glands bilaterally. Each of these four patients had a clinical diagnosis of Sj?gren syndrome. One of the four underwent sialography, which demonstrated characteristic sialectasia. Pathologic examination of an excised gland in one of the patients with Sj?gren syndrome demonstrated typical benign lymphoepithelial aggregates, which cause obstruction and progressive ductal dilatation. While parotid enlargement in these patients may be due to salivary tumor, lymphoma, or sarcoidosis--all of which appear as solid lesions at sonography--this study suggests that bilateral cystic changes may be the rule in uncomplicated cases of Sj?gren syndrome.     

Ovary volume in young and premenopausal adults: US determination. Work in progress

Normal adult ovary volume determined by ultrasonography (US) is often stated to be less than 6 cm3. This is based on data from teenagers and young adults aged 12-20 years. Recently, the mean normal volume determined by US was reported to be considerably higher. We measured the volumes of 28 ovaries from 15 healthy young adults and found them to range as high as 13.84 cm3, with an average of 6.48 cm3.     

Surgical portosystemic shunts in children: assessment with duplex Doppler US. Work in progress

The patency of 12 surgical portosystemic shunts in 11 children with portal hypertension was assessed with duplex Doppler ultrasonography. Results were compared with surgical, angiographic, and clinical findings. Seven of nine patent shunts were directly seen, and flow in them was assessed. One proximal splenorenal and one mesentericocaval shunt were not directly seen because of intestinal meteorism. The obstructed shunts were not seen, and no flow could be detected at their site. The presence and direction of flow in the splanchnic venous system were determined in all children, obviating the need for further angiographic studies.     

Three-dimensional US of the prostate: early experience.

PURPOSE: To assess the feasibility of using a three-dimensional (3D) endorectal transducer at ultrasonography (US) in the prostate gland in a clinical setting. MATERIALS AND METHODS: Sixteen patients underwent 3D imaging of the prostate gland with a 3D endorectal probe following conventional two-dimensional (2D) US and prior to prostatic biopsy. Image acquisition was performed as a volume of data with nearly immediate reconstruction and simultaneous display of sectional anatomy in three orthogonal planes--sagittal plane, transverse or coronal plane, or any arbitrary oblique plane. Images were evaluated for presence of focal lesions, glandular volume, visualization of lateral and anterior portions of the gland, and extraglandular extension of tumor. RESULTS: Three-dimensional US allowed better visualization of the gland and focal lesions, especially on the coronally reconstructed images, which were judged superior to the sagittally or transversely reconstructed images for interpretation in 50% of the patients. Prostatic volumes obtained from 3D US were consistently smaller than volumes obtained from 2D US (20% difference, P = .006). Three-dimensional US was superior to 2D US in depicting tumor presence (nine of 10 right hemispheres, three of eight left hemispheres) and extraglandular extent of disease (three of five hemispheres). CONCLUSION: Three-dimensional endorectal prostatic US appears to be clinically feasible and easy to perform. Added anatomic information from the coronal plane may allow better depiction of tumors and extraglandular spread than is possible with current 2D techniques.     

Empty-bladder (hysterographic) view on US for evaluation of intrauterine devices. Work in progress

Ultrasound scanning of the pelvis with an empty bladder permits a true frontal view of the uterus to be easily obtained. This view is comparable to the en face view seen at hysterography performed with contrast material. Good definition both of the endometrium and the uterine wall makes this the optimal method for the evaluation of an intrauterine contraceptive device.     

Normal standards for kidney length in premature infants: determination with US. Work in progress

In 52 healthy premature infants, 104 kidneys were sonographically examined and kidney length was measured. Kidney length was compared with four parameters: body weight, body length, body surface area, and gestational age. Scatter plots of these data demonstrated that kidney length versus body weight conformed well to a linear distribution with a high correlation coefficient. A nomogram for kidney length versus body weight in premature infants is also presented.