Biomedical subjects
F Winsberg
Publications and source records attributed to F Winsberg.
Focal hepatic vein stenoses in diffuse liver disease.
To determine the frequency of focal hepatic vein stenosis in diffuse liver disease and to study the relationship of stenosis to abnormal hepatic venous Doppler waveforms, 92 patients being evaluated for liver transplantation or transjugular intrahepatic portosystemic shunt were prospectively studied with color flow and pulsed Doppler sonography for the presence of focal hepatic vein stenoses and waveform abnormalities. Thirty-six patients had no focal stenoses with normal curves, 26 of 38 patients with Bolondi type I curves had focal stenoses, and 10 of 18 patients with damped type II curves had focal stenoses. Damped hepatic venous velocity curves associated with liver disease probably are caused by increased resistance in the hepatic venous circulation produced by focal stenoses.
Variability in measurement of central retinal artery velocity using color Doppler imaging.
The purpose of our study was to test the reproducibility of the central retinal artery velocity measurements as made by color Doppler imaging and pulsed Doppler spectral tracings and to define the optimal location for placement of the sample volume. We used the Siemens Quantum (Q 2000) with a 7.5 MHz linear array transducer to identify the central retinal artery and record its velocity. Eleven eyes from 11 normal subjects were evaluated for the peak systolic central retinal artery velocity in two positions, the first posteriorly in the optic nerve at an average of 3.56 mm from the surface of the optic disc and the second at an average of 1.76 mm from the surface of the optic disc. We then used a color-flow threshold to identify and record the point of maximal velocity. The range of systolic velocities in the 11 eyes was from 5.85 to 22.51 cm/sec. The peak systolic velocity posteriorly in the optic nerve averaged 8.16 cm/sec, whereas near the surface of the optic disc the velocity averaged 13.89 cm/sec (70.2% higher). Using the color flow threshold method, the maximal velocity was located at an average of 1.98 mm from the surface of the optic disc. Our data show that large differences exist in measured central retinal artery velocity that depend on the location of the measurement, and that color-flow thresholding is valuable in locating the optimal location for pulsed Doppler spectral recording.
Doppler features of distal internal carotid artery stenosis.
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Variability of hepatic vein Doppler tracings in normal subjects.
A prospective study was undertaken to determine the variability of hepatic vein Doppler waveforms in normal subjects. Seventy-five patients without liver or heart disease underwent Doppler examination of the middle hepatic vein. Normal triphasic tracings were observed in 68 subjects, while flattened tracings were observed in seven subjects. In addition, in four of the seven subjects with flattened tracings, an increase in pulsatility was seen during prolonged inspiration. We conclude that there is variability of hepatic vein tracings in normal subjects and that respiratory maneuvers can alter these tracings.
Color Doppler sonography of vascular malformations of the liver.
Nine cases of intrahepatic vascular malformations diagnosed using color Doppler sonography are described. These consisted of six cases of intrahepatic portal-hepatic venous shunts and three cases of arteriovenous fistulas. Among these is a case of multiple intrahepatic portal-systemic shunts. The sonographic findings and theories explaining the formation of vascular malformations in the liver are discussed.
Use of an acoustic transponder for US visualization of biopsy needles.
A 20-gauge Chiba needle with a stylet embedded with polyvinyldifluoride (PVDF), a polymer that acts as an acoustic-electric transducer, facilitated a variety of diagnostic and therapeutic ultrasound (US)-guided interventions in nine patients. PVDF receives acoustic energy from the US scanner and transmits an electrical signal through the stylet and a shielded cable to the scanner, which results in appearance of a bright echo on the monitor at the location of the needle tip.
Comet-tail artifact from cholesterol crystals: observations in the postlithotripsy gallbladder and an in vitro model.
The "comet tail" is a well-known ultrasound artifact that appears as a series of parallel bands radiating from a source. This artifact was observed in the gallbladder lumen in eight of 10 patients after extracorporeal shock wave lithotripsy of radiolucent calculi. To investigate the cause of the comet tail artifact, cholesterol crystals were studied in an in vitro model. The comet-tail appearance was reproduced in vitro and was found to be directly related to the interrogating frequency and the size of the crystal aggregates. The authors conclude that cholesterol crystals can serve as the source of the comet-tail artifact secondary to reverberation within the crystals.
The normal post-cholecystectomy sonogram: gas vs. clips.
Although both gas and heavy metals create multiple reverberations, they can be distinguished both in vivo and in vitro by the differences in origin (focus) and the duration (persistence) of the artifact. A phantom experiment showed that surgical clip artifacts emanate from short echogenic foci, and are persistent, whereas gas foci are either long or short, with evanescent artifacts. In 78 consecutive post-cholecystectomy patients, 96 per cent (24/26) of the patients with clips demonstrated multiple reverberation artifacts, whereas 6 per cent (2/31) of the patients without clips demonstrated several reverberation artifacts. Analyzing these characteristics as well as the positional relationships of reverberation artifacts in the porta hepatis and gallbladder fossa should enable one to suspect the post-cholecystectomy state and differentiate from an abnormal gas collection.
The air-filled left hepatic duct: the saber sign as an aid to the radiographic diagnosis of pneumobilia.
In the supine patient, gas rises to the left hepatic duct. Radiographically, this can be recognized as a saber-shaped lucency to the right of the spine. In a retrospective analysis and review of the radiographs of 40 patients shown to have gas in the biliary tree by ultrasound (US), computed tomography (CT), or radiography, the diagnosis could be made in 37 patients. In 18 of these 37 cases pneumobilia could be identified by the saber-shaped distribution of gas. Knowledge of the medial distribution of biliary gas in the supine patient and appreciation of the saber sign can increase the sensitivity of the radiographic detection of pneumobilia.
Femur length measurements with sector scanner.
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Echocardiographic demonstration of pericardial fluid adjacent to the right atrial wall.
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Echographic appearance of the right hemidiaphragm.
In a prospective evaluation of the right upper quadrant in 100 consecutive healthy subjects, three echogenic lines were visualized in the right posterior, superior, and lateral aspects of the abdomen in the region of the right hemidiaphragm in approximately 80 per cent. A retrospective review was made of the sonograms of 33 patients with right pleural effusions alone, 14 patients with ascites alone, and ten patients with combined ascites and pleural effusions. Analysis of the number of echogenic lines seen in the region of the right hemidiaphragm and their relationship to the gas reverberation artifact suggests that two of the three lines seen in scans of normal subjects represent actual structures (diaphragm--liver capsule complex and lung--visceral pleura an in-vitro model constructed to simulate the liver, diaphragm, lung, and pleural effusion support the hypothesis that the lung and not the diaphragm is the mirror of the right upper quadrant.
Real-time identification of blood flow in the placenta and umbilical cord.
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Sonographic demonstration of the right paramediastinal pleural space.
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Incidence of aortic cusp and mitral annulus calcification as determined by echocardiography: significance and interrelationship.
M-mode and two-dimensional echocardiograms of 3,254 patients without evidence of rheumatic heart disease were evaluated retrospectively for evidence of aortic cusp calcification and mitral annulus calcification. Echographic evidence of mitral annulus calcification was found in 6.3% of the patients studied. In 375 patients with echographic evidence of aortic valve calcification, the incidence of mitral annulus calcification was 30.6% and it was more than twice as common in females (44.9%) as in males (19.2%). Mitral annulus calcification in patients with aortic cusp calcification was age- and gender-dependent. It occurred in 25% of women younger than 50, 50% of women over 60, and 60%Q of women over 80 years of age. The incidence in males was 28.5% and 27% in the 70s and 80s, respectively. There was no correlation between the severity of aortic valve calcification of stenosis and the incidence of mitral annulus calcification.
Gallbladder wall thickness distortion by ascites.
Eight patients with sonographically demonstrated ascites adjacent to or surrounding a gallbladder wall of normal thickness are described. In two patients, improper transducer placement or angulation caused apparent gallbladder wall thickening. Two in vitro experiments, one with a balloon phantom and the other with a resected gallbladder, confirmed that wall thickness varies with transducer placement and angulation. Ascites per se neither causes gallbladder wall thickening nor results in artifactual thickening if the beam angle is controlled.