Utility of leg ultrasonography in suspected symptomatic isolated calf deep venous thrombosis.

PURPOSE: To evaluate the utility of duplex ultrasonography in patients with suspected symptomatic, isolated calf deep venous thrombosis. PATIENTS AND METHODS: Thirty patients with clinically suspected isolated calf deep venous thrombosis were examined with both duplex ultrasonography and contrast venography and the results were compared. RESULTS: Venography detected 7 cases of isolated calf deep venous thrombosis, all of which were also detected by ultrasonography. Ultrasound identified an additional 3 cases of soleal vein thrombosis, but venography did not visualize these veins. Of the 20 negative ultrasound studies, 11 were technically inadequate; however, no false-negative ultrasound studies were noted. CONCLUSIONS: Compression ultrasonography may be reliable for the evaluation of patients with suspected symptomatic infrapopliteal deep venous thrombosis. Its apparent superiority to contrast venography in visualizing muscular calf veins warrants further study; however, the high rate of technical inadequacy in ultrasound studies observed here, if confirmed in larger studies, may limit the usefulness of ultrasound in this setting.

Recurrent thrombosis of polytetrafluoroethylene dialysis fistulas after recent surgical thrombectomy: salvage by means of thrombolysis and angioplasty.

PURPOSE: To test the hypothesis that thrombolysis followed by angioplasty for salvage of thrombosed polytetrafluoroethylene (PTFE) dialysis fistulas is safe and effective even after recent surgical thrombectomy. MATERIALS AND METHODS: Thrombolysis and balloon angioplasty were performed on 12 fistulas in which thrombosis had recurred within 30 days after thrombectomy (n = 10) or thrombectomy/revision (n = 2). All patients underwent pulse-spray pharmacomechanical thrombolysis with urokinase and use of a crossed-catheter technique. A total of 250,000-1,000,000 IU of urokinase and 2,500 IU of heparin were injected throughout the clot in 17-33 minutes. A bolus of 2,500 IU of heparin was simultaneously administered intravenously. RESULTS: Thrombolysis was successful in restoring flow in all grafts, but thrombosis recurred in three grafts before they could be used for dialysis. The clinical success rate was thus 75%. There were no major complications. Mean primary patency after thrombolysis in this small select group of patients was 94 days (median, 68.5 days), comparing favorably with the mean patency of 44 days (median, 23 days) achieved by the prior 23 surgical revisions in the same grafts. CONCLUSION: Percutaneous fistula salvage appears to be a safe and effective means of treating recurrent thrombosis in PTFE dialysis fistulas when recent surgical thrombectomy has failed.

A criterion for a true lateral radiograph of the elbow in children.

In the search for a fracture of the elbow in children, the position of the anterior humeral line is a valuable aid. It has been stated that a true lateral radiograph is required to use this sign, although no criteria for assessing true laterality have been described. To develop such criteria, the authors examined 74 lateral radiographs of the elbow for 42 patients ranging in age from 9 months to 5 years, 9 months. Thirty-five of the patients did not have supracondylar fractures, and 7 did. In all of the radiographs the direction and degree of rotation, as well as the position of the anterior humeral line, were assessed relative to a series of radiographs of a cadaveric humerus in standardized positions. Examination of the humeral anatomic features in the radiographs showed that superimposition of the posterior supracondylar ridges of the humerus is the best means of confirming true laterality. This criterion is easily applied to lateral radiographs of the elbow in children. Of the radiographs reviewed, only seven were considered to represent true lateral views. Of those exposed in other degrees of rotation, the anterior humeral line gave a false indication of fracture in 19.

First-trimester umbilical cord cysts.

Cystic masses of the umbilical cord have been detected in the 2nd and 3rd trimesters of pregnancy in association with fetal abdominal wall defects and chromosomal anomalies. With high-resolution endovaginal ultrasound (US), umbilical cord cysts can be visualized during the 1st trimester. Their origin and significance must be considered for proper obstetric management. The authors report eight cases in which cystic masses of the umbilical cord were detected during US examinations performed at 8-9 weeks menstrual age. In the five cases followed to term, both the infant and the umbilical cord were found to be normal at physical examination. Sonographically, all cysts appeared to be eccentric in relation to the umbilical cord, and, although all were closer to the fetus, the cysts were clearly extraembryonic. Cyst size was 2.0-7.5 mm (mean, 5.2 mm). Seven cysts resolved by 12 weeks menstrual age. The incidence of cysts in patients who underwent US at the authors' institution between 8 and 12 weeks menstrual age was 0.4%; the true frequency is unknown without routine 1st-trimester scanning of all patients.

Three-dimensional lithographic model building from volume data sets.

Computed tomographic images of a dry human skull and an in-situ knee joint were used to construct solid three-dimensional polymer models using stereolithographic techniques that have been introduced recently into the manufacturing industry. The stereolithographic technique makes use of a computer-steered narrow laser beam to solidify the model within a bath of liquid photocurable polymer. The method does not suffer from the cutting-tool size and path constraints encountered in the more commonly used process of machining the models from a solid block of foam.

Conversion of albumin into a transmitter of the ultra long-range interaction of human erythrocytes.

Previous experiments in our laboratory and elsewhere have shown that extended macromolecules of high molecular weight are needed in the suspending medium to transmit the quantum-mechanical coherent interaction of human erythrocytes. Albumin, a globular protein, does not transmit the interaction at physiological concentrations. Albumin can be converted into a transmitter by preheating a solution of albumin to 62 degrees C for 20 min. Such treatment unravels the tertiary structure of albumin and allows it to polymerize.