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B H Thompson

Publications and source records attributed to B H Thompson.

At least 37 records · Page 2Linked to original sources
PubMed1994

Contrast-enhanced thin slice ultrafast computed tomography for the detection of small pulmonary emboli. Studies using autologous emboli in the pig.

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.

Animals↗
PubMed1994

Evaluation of cardiac function with ultrafast computed tomography.

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.

Cardiac Output↗
PubMed1993

Nonangiographic assessment of coronary artery bypass graft patency.

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.

Angina Pectoris↗
PubMed1993

Utility of ultrafast computed tomography in the detection of thoracic aortic aneurysms and dissections.

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.

Aortic Dissection↗
PubMed1993

Coronary artery calcification: clinical significance and current methods of detection.

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.

Calcinosis↗
PubMed1993

Coronary artery visualization using ultrafast computed tomography.

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 Disease↗
PubMed1991

Two new uses of 8-F feeding tube in performing injecting urethrograms.

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.

Catheterization↗
PubMed1991

Evaluation of great heart vessels and pulmonary vasculature.

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.

Aorta, Thoracic↗
PubMed1989

Thrombus-trapping efficiency of the Greenfield filter in vivo.

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.

Animals↗
PubMed1989

Traumatic brain stem injury: MR imaging.

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.

Acute Disease↗
PubMed1989

Incidental fibromuscular dysplasia in potential renal donors: long-term clinical follow-up.

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.

Adult↗
PubMed1977

Hereditary deficiency of the third component of complement in a child with fever, skin rash, and arthralgias: response to transfusion of whole blood.

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.

Blood Transfusion↗
PubMed1977

Studies on the attraction of Simulium damnosum s.l. (Diptera: Simuliidae) to its hosts. II. The nature of substances on the human skin responsible for atrractant olfactory stimuli.

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.

Animals↗