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Electron Beam Computed Tomography (EBCT), like conventional CT has the capability to acquire high resolution images of the aorta. The millisecond image acquisition time characteristic of EBCT makes it an ideal modality to evaluate patients with suspected aneurysms or dissections of the aorta. Unlike conventional CT, electron beam technology produces images with excellent resolution, minimal respiratory artifact, and superior vascular enhancement. Compared with alternative modalities, EBCT probably represents a superior tool in the workup of aortic pathology. Whether in the acute or chronic setting, the reliability, speed, ease, and reproducibility of EBCT makes it truly superior in the diagnosis and follow-up of aortic aneurysms and dissections.

Ultrafast computed tomography (UFCT) possesses many features that make it uniquely capable in performing measurements of cardiac function. Over the years, numerous validation studies have verified UFCT's ability to provide qualitative and quantitative information about cardiac performance. Documented accuracy and reproducibility in measuring functional parameters, such as volume, mass, contractility, and cardiac output, make UFCT a valuable tool in cardiac imaging.

Rationale and Objectives: Ultrafast computed tomography (UFCT) has proven useful, but is of limited practical application in the diagnosis of central pulmonary embolism; however, its ability to detect more peripheral emboli has not been established. In this study, the use of contrast-enhanced UFCT images for the detection of autologous peripheral pulmonary emboli in the pig is evaluated., Methods: A single autologous embolus measuring 0.7 x 1.5 cm was introduced into the superior vena cava of eight pigs. Contiguous, 3-mm axial UFCT images from the lung apex to the base were obtained before and after the introduction of the embolus. After scanning, the pigs were killed, and the thorax was removed intact and was frozen in a dry ice-alcohol mixture. Later, the thorax was sliced at 10-mm thicknesses, and the locations of the emboli were determined by a pulmonary pathologist blinded to the imaging results. Concomitantly, the locations of the emboli were determined by consensus of three chest radiologists blinded to the autopsy results., Results: In 6 of 8 animals with emboli, the embolus location correlated exactly with the autopsy findings. In one, the embolus was on the same side, but 1.6 cm further distal. In the other, a marking suture was identified, but no clot was identified on the pathologic or UFCT examination. In the eight animals scanned before the introduction of the embolus, no embolus was found. Interobserver agreement was 100%., Conclusions: Ultrafast computed tomography has the potential to detect autologous emboli in second- to fourth-division pulmonary vessels. Further studies are needed to determine if in vivo emboli can be similarly visualized.

Coronary artery disease affects 1,500,000 Americans each year; 500,000 of these will die. The earliest detectable lesion of coronary atherosclerosis is the fatty streak. Later, crescent-shaped lipid plaques occur, which may rupture and produce either progressive stenosis or sudden occlusion with myocardial infarction. Calcium is deposited early in the formation of the atherosclerotic plaque, and calcification can be used as a marker of the atherosclerotic process. Many imaging techniques can be used to detect calcification of coronary arteries. The most promising are fluoroscopy, ultrafast CT, and intravascular sonography. Detection of calcification is most valuable in persons less than 40 years old in whom modification of risk factors may be important. In addition, the progression and possible regression of calcification can be used as an indicator of the atherosclerotic process. The absence of calcification in coronary arteries may diminish the need for further testing.

The authors previously demonstrated the feasibility of graph-searching-based automated edge detection in cardiac magnetic resonance (MR) imaging. To further assess the clinical utility of this method, unselected images from 11 consecutive subjects undergoing clinically indicated (except for one healthy volunteer) short-axis spin-echo MR imaging were analyzed. A total of 142 images from the 11 subjects, encompassing the left ventricle from apex to outflow tract, were analyzed. The computer algorithm correctly identified complete endocardial and epicardial contours in 121 of 142 images (85%). Correlations between observer-traced and computer-derived epicardial areas for all images were good (r = .71 for epicardium, r = .83 for endocardium); they improved for a subset of higher-quality images (r = .82 for epicardium, r = .92 for endocardium). The authors conclude that the current data further support the usefulness of computer digital image processing in geometric analysis of cardiac MR image data.

The advantages and limitations of ultrafast computed tomography in the imaging of normal and pathologic conditions of the coronary artery are discussed. The scanner's speed, resolution, and lack of significant motion artifact enhance the visualization of coronary arteries. Coronary artery calcification also is well visualized, and coronary artery fistuli, coronary bypass graft patency, and Kawasaki disease can be assessed accurately using contrast-enhanced flow studies. The inability to image stenoses and the lack of longitudinal images detract from its usefulness. Future scanner upgrades to provide increased resolution and thinner slices should improve the scanner's ability to evaluate the coronary artery.

Coronary artery bypass graft patency can be assessed using the indirect techniques of evaluating patients' symptoms and exercise tolerance, changes in stress electrocardiogram, radioisotope regional perfusion, and myocardial wall contraction. The direct techniques assess graft patency directly by visualizing grafts using conventional computed tomography (CT), ultrafast CT, magnetic resonance imaging, digital subtraction angiography, and echocardiography. The advantages and disadvantages of each of these modalities are reviewed. At the present time, ultrafast CT and possibly magnetic resonance imaging and Doppler appear to be the only techniques besides angiography that can consistently evaluate bypass graft patency. Although they have the advantage of being minimally invasive, they cannot show graft stenosis or sequential graft patency. These techniques are best used in following patients after coronary bypass graft surgery and ruling out graft closure as the source of chest pain.

The millisecond image acquisition time characteristic of the ultrafast computed tomography (UFCT) scanner makes it an ideal modality for evaluating patients with suspected vascular lesions of the thoracic aorta. Unlike conventional CT, the UFCT electron beam technology produces images with excellent resolution, minimal respiratory artifact, and superior vascular enhancement. This report discusses the (1) basic characteristics of the UFCT scanner as they relate to the imaging of the thoracic aorta, (2) UFCT appearances of uncomplicated and complicated aneurysms and dissections, (3) appropriate CT protocols used in the work-up of suspected thoracic aortic disease, and (4) strengths and weaknesses of other imaging modalities compared with UFCT.

This year's literature relating to imaging of the great heart vessels was devoted primarily to measurements of aortic size and to comparisons of imaging modalities in evaluating aortic aneurysms, dissections, and coarctation. The imaging modalities compared were plain chest roentgenography, conventional CT, ultrafast CT, MR imaging, transcutaneous esophageal echocardiography, and Doppler echocardiography. The pulmonary vasculature literature dealt with MR imaging of pulmonary vessels and the estimations of pulmonary pressure using echocardiography and Doppler techniques.

A modification of a previously described method for visualizing the urethrovesical junction is described. This modification is easier to perform, less messy, and obtains superior images to the method now used. A new method for outlining urethral strictures is also described. Both methods use an 8-F feeding tube.

A previously well 34-month-old male presenting with fever, skin rash, and arthralgias was found to lack C3 by immunochemical (undetectable) and hemolytic (1% normal) assays. No infectious agent could be demonstrated. Protein levels of Clq. C4, C5, properdin, and C3b-INA and hemolytic activities of complement components C1 to C9 except C3 were normal or elevated; total hemolytic complement activity was 13% of normal and was reconstituted by purified C3. Properdin factor B was 702 (normal 175 to 275) mug/ml, and was not cleaver upon addition of zymosan or cobra venom factor. The serum had normal immune adherence activity, but was deficient in ability to opsonize Candida albicans for uptake and Escherichia coli for killing by neurophils, generate neutrophil chemotactic factors and inhibit the growth of E. coli; these activities were restored by purified C3. A transfusion of 320 ml 1-hour-old normal whole blood on the fifty-second day resulted in transitory elevation of the C3 level to 25 mg/dl with a fall-off (approximately 2 1/2% per hour) to undetectable levels by 69 hours; it was followed by disappearance of the skin rash and arthralgias and return to normal of the previously elevated temperature and CRP levels. C3 levels in family members (seven of 24 half-normal), lack of anti-C3 activity, normal C3b-INA levels and a normal rate of catabolism of transfused C3 indicated that the deficiency was inherited with autosomal codominance and involved decreased synthesis of C3. Thus, this child is a unique individual with inherited C3 deficiency presenting with absence of repeated infections, whose symptoms of fever, skin rash, and arthralgia were abated by whole blood transfusion.

Five marking/recapture experiments were carried out on Simulium damnosum in the rain-forest of the United Republic of Cameroon, in order to determine the regression in biting density at increasing distances from the marking point. Flies were captured unfed, marked with fluorescent dust, and then released on the bank of a large river. Recaptures were made over the six-seven days after marking, at seven stations situated from 200 m to 79 km along a large river, from the marking site. Marked flies, which showed fluorescent pigment when examined under an ultraviolet lamp, were recovered at all seven sites. The ratios of the number of recaptures per man-hour at each distant site to the recaptures per man-hour at the marking point were calculated to obtain values for the proportional biting density (Z). The value of Z declined in a logarithmic manner with increasing distance from the marking site, such that it fell to 0-1 at distances of 34-1 km on a large river, 5-5 km on a small river, and 1-5 km on a road leading away from a large river. The peak number of flies recaptured at the farthest sites along a large river (56 km and 79 km) occurred one day later than at the station nearest the marking point. The dispersal of marked flies which had fed on volunteers carrying Onchocerca volvulus microfilariae, was studied along a large river. Of three flies recaptured 24 km upstream from the marking point, one contained 10 infective larvae of O. volvulus.

In the forest zone of the United Republic of Cameroon, a live chicken proved far more attractive to hunting S. damnosum s.l. than did a live sheep; but in the Sudan-savanna zone, a sheep was more attractive than a chicken. It is suggested that the populations of flies in the two areas represented different species of the S. damnosum s.l. complex with different host-finding mechanisms, that in the forest (? S. squamosum) hunting mainly by smell, and that in the Sudan savanna (? S. damnosum s.s.) hunting mainly by sight.

Female sterilization by laparoscopy has become widely accepted throughout the United States and Europe. The failure rate of this procedure is still speculative. In the course of 4200 operative sterilization, 32 failures have been identified and 31 of these have been subsequently evaluated. The most common finding was inadequate or superficial fulguration and resection. Operative errors such as round ligament fulguration were also more common than expected.

The clinical natural history of renal arterial fibromuscular dysplasia (FMD) in patients with normal blood pressure is unknown, to the authors' knowledge. The authors reviewed the results of 1,862 renal angiograms obtained in potential renal donors. FMD was present in 71 patients (3.8%). The average age at which FMD was discovered was 50.8 years. Seventy-five percent of the patients with FMD were female. Of 30 patients who did not undergo nephrectomy, eight (26.6%) developed hypertension over a mean followup interval of 7.5 years. Of 19 patients who underwent nephrectomy, despite the presence of FMD, five (26.3%) developed hypertension over a mean follow-up interval of 4.4 years. In comparison, three subjects (6.1%) (from a randomized control group of 49 age- and sex-matched healthy individuals) developed hypertension over a mean follow-up period of 7.1 years. The authors conclude that asymptomatic middle-aged individuals with renal FMD develop hypertension at a rate greater than that of age-matched control subjects with normal blood pressure.

There are several methods for measuring the susceptibility of blackfly larvae to insecticides. In 1970 the provisional method suggested by the World Health Organization was used with a view to establishing baseline data on the susceptibility of S. damnosum larvae to insecticides; this method was found to be unsuitable. Thereafter, attempts were made to develop a reliable susceptibility testing method for S. damnosum. This report describes the method that yielded the best results in the laboratory; a second method suitable for use in the field is also described. The results from several replicates of such tests gave reasonably straight log-dosage-probit-mortality curves from which values of LC(50) could be calculated. The overall control mortality in the laboratory series of tests was about 9% and that in the field series was about 4%.

Eighty-seven patients with acute (n = 70) or chronic (n = 17) head injuries were prospectively studied with magnetic resonance (MR) imaging and computed tomography (CT) to characterize the frequency and nature of traumatic brain stem injury (BSI). Forty-eight traumatic lesions were identified in 36 patients. Of 36 patients, 35 had neurologic findings that corroborated the radiographic impression of BSI. T1- and T2-weighted MR images demonstrated a significantly higher number of lesions than did CT. Patients with BSI had a significantly higher frequency of corpus callosum and diffuse axonal "shear" lesions. The number of cortical contusions and extraaxial hematomas was similar in both groups. The mean Glasgow Coma Scale (GCS) scores at admission were significantly lower in patients with evidence of BSI on MR images. Patients with primary BSI had lower initial GCS scores, a longer duration of coma, more diffuse axonal "shear" lesions, and a higher frequency of corpus callosum injury than patients with secondary BSI. The location of primary and secondary lesions was significantly different. Overall, MR imaging was more helpful than CT in detecting, localizing, and characterizing BSI.

In the Cameroon rain-forest, electric fan traps, baited with trousers which had been worn by men for several days, captured more females of S. damnosum s.l. than did traps baited with worn shirts of similar material. A number of human body fluids were used as bait, but only sweat appeared to contain the olfactory attractant(s). The fluid portion of filtered arm sweat attracted more flies than did the residue. The attractant substances from human skin would not dissolve directly in organic solvents, but when an artificial sweat solution was used to swab men's arms and legs, and this was then saturated with salt and shaken with an organic solvent, the extract was attractive to S. damnosum. Treatment of attractive worn cloths with dilute aqueous solutions of hydrochloric acid, sodium hydroxide or mercuric chloride greatly reduced their attractiveness. A number of organic compounds which occur on the human skin were found to be ineffective as attractants.

Four traps used in capturing hunting female S. damnosum s.l. are discribed: the slat trap, the enclosure trap, the fan trap, and the sticky trap. In forest a man hidden inside a trap, but removing his exhaled breath through a long hose, attracted 4 times as many flies as did an unbaited trap. When the man exhaled normally into the trap the number of flies taken rose again by a further factor of 4. Carbon dioxide gas, emitted from inside the trap attracted some two-thirds as many flies as a man exhaling normally inside the trap. In both forest and Sudan-savanna environments the catches of a man stationed on an open stretch of land and fully exposed to view while his exhaled breath was removed through a long hose, were not substantially lower than those of a man in a similar situation who exhaled normally. In forest a motionless man, partly hidden among vegetation, attracted fewer flies than a moving man who was fully exposed to view (a) when both men removed their exhaled breath through long hoses, and (b) when they exhaled normally. In the forest a trap baited with CO2 gas (250 cc per min) caught more flies than a similar, unbaited trap, but the preformance of CO2-baited traps, as compared with that of human collectors, was highly variable. Catches in CO2-baited traps were uniformly low in the Sudan-savanna. In forest, removal of olfactory substances from the human skin, by vigorous washing and application of petroleum jelly, or by wearing impermeable clothing, greatly reduced the numbers of flies attracted. No such reduction was observed in Sudan savanna. In the forest, cloths, worn by men for several days and then used as bait, attracted about 10 times as many flies as did similar, unworn cloths. Addition of CO2 gas produced a 4-fold increase in the attractiveness of worn cloths and an 18-fold increase in that of unworn cloths. No corresponding experiments were done in the savanna. Fan traps could become contaminated by human handling during the assembly and setting-up procedures. They were thus rendered attractive to flies. In the Sudan-savanna, the catches of men positioned in front of warm rock surfaces were lower than those of men stationed on coller, sandy surfaces. This suggests that body heat may be an additional attractant factor. The results suggest that "forest" S. damnosum s.l. (presumably S. squamosum) females rely heavily on smell as an attractant and, to a lesser extent, on sight and exhaled breath. Smell appears to be the only obligatory attractant, and it can act by itself. This raises the possibility that a trap might be developed which incorporates only smell stimuli as bait. For "savanna" S. damnosum s.l. (presumably S. damnosum s.s.) neither smell nor exhaled breath appear to be important attractants, and some other factor, perhaps sight, appears to be the dominant attractant in this zone.

A total of 100 radiopaque blood clots were injected into seven adult sheep under fluoroscopic observation to assess the clot-trapping efficiency of the Greenfield vena caval filter. Eleven percent of the clots passed through the filter, with all failures limited to the two smallest clot sizes: 4 x 10 mm (five of 25) and 4 x 30 mm (six of 25). The Greenfield filter was 100% efficient in trapping larger clots (8 x 10 mm and 8 x 30 mm). There was a tendency toward poorer clot-trapping performance when the Greenfield filter was tilted within the vena cava, but this was not significant. There were no significant differences in hemodynamic measurements obtained immediately before and after injection of each clot, and no significant changes were noted in the animal's hemodynamic status or in blood gas measurements in those cases in which the clots passed through the filter. Since the caval diameter in sheep approximates that in humans, the authors conclude that the Greenfield filter in the clinical setting is capable of stopping large, likely fatal, emboli and a large number of smaller, possibly less clinically significant, emboli.

Obstetric ultrasonography has made the prenatal diagnosis of gastroschisis and omphalocele more common. We present illustrative cases and review the ultrasonographic features. Because of the increased risk of concomitant abnormalities (including trisomies) with omphalocele, full evaluation is indicated when this diagnosis is suspected. Recent perinatal approaches to delivery have favoured caesarean section, without scientific evidence that outcome is improved. Our experience, as well as a review of the literature, suggests that the outcome for vaginally delivered infants is acceptable. A prospective study of this question is needed.

Six marking-recapture experiments were carried out with Simulium damnosum in the Cameroon Republic, five in the rain-forest and one in the Sudan-savanna zone. Adult flies were marked by applying a small spot of oil paint to the mesonotum while they were engorging with blood on the legs of volunteers infected with Onchocerca volvulus microfilariae. Catches of wild flies were carried out for 12-13 days after the first day of marking, and all marked flies recaptured were examined. Some of the flies recaptured on days 0, 1 and 2 were nulliparous and had probably been disturbed by the application of the paint before they had completed their blood-meal. The frequency distribution of recaptured marked parous flies returning for their "second" blood-meal rose to a peak early on day 4, but more flies returned earlier,three days after taking a blood-meal, than later on day 5. After day 5, the numbers of recaptured flies were too low to demonstrate any peaks corresponding to "third" and later blood-meals. The longest surviving fly was recaptured 10 days after marking. Twenty-six percent of the flies recaptured on days 3 and 4 contained developing O. volvulus larvae three-five days old, which had presumably been ingested as microfilariae during the blood-meal taken on day 0. Infective larvae first appeared in flies returning late on day 6, and the highest percentage of infective flies occurred on day 7. Infective larvae were found in recaptured flies until day 10, the last day on which marked flies were recovered. Of 929 flies marked on the Sudan-savanna experiment, three (0-32%) flies were recaptured. Two returned on day 4 and one on day 6.