Biomedical subjects

J F Breen

Publications and source records attributed to J F Breen.

At least 37 records · Page 2Linked to original sources

PubMed1996

Giant coronary artery aneurysms and myocardial infarction in a patient with systemic lupus erythematosus.

A 26-year-old woman with systemic lupus erythematosus and end-stage renal disease presented for renal transplantation. She had no findings of cardiac disease. Radiologic evaluation, cardiac magnetic resonance imaging, and coronary angiography showed giant aneurysms of the right and left anterior descending coronary arteries. Despite therapy, acute anterior myocardial infarction developed during follow-up. Giant coronary artery aneurysms associated with systemic lupus erythematosus are unusual and their management is controversial. Antithrombotic therapy probably should be considered for giant coronary artery aneurysms.

Adult↗

PubMed1996

Dynamic MR digital subtraction angiography using contrast enhancement, fast data acquisition, and complex subtraction.

A dynamic MR angiography technique, MR digital subtraction angiography (MR DSA), is proposed using fast acquisition, contrast enhancement, and complex subtraction. When a bolus of contrast is injected into a patient, data acquisition begins, dynamically acquiring a thick slab using a fast gradient echo sequence for 10-100 s. Similar to x-ray DSA, a mask is selected from the images without contrast enhancement, and later images are subtracted from the mask to generate angiograms. Complex subtraction is used to overcome the partial volume effects related to the phase difference between the flowing and stationary magnetization in a voxel. Vessel signal is the enhancement of flow magnetization resulting from the contrast bolus. MR DSA was performed in 28 patients, including vessels in the lungs, brains, legs, abdomen, and pelvis. All targeted vessels were well depicted with MR DSA. Corresponding dynamic information (contrast arrival time ta and duration of the arterial phase tav) was measured: ta/tav = 3.4/4.7 s for the lung, 10.3/4.9 s for the brain, 12.8/19.3 for the aorta, 15.2/12.6 s for the leg. MR DSA can provide dynamic angiographic images using a very short acquisition time.

Abdomen↗

PubMed1996

Cardiac magnetic resonance fluoroscopy.

A technique is described for high speed interactive imaging of the heart with either white or black blood contrast. Thirty-two views of a segmented, magnetization-prepared gradient echo sequence are acquired during diastole. Using three-quarter partial Fourier sampling, data for a complete 128 x 128 image are acquired in three cardiac cycles. High speed reconstruction provides an image update of each cardiac cycle 159 ms after measurement. An independent graphical user interface facilitates interactive control of section localization and contrast by permitting pulse sequence parameter modification during scanning. The efficiency and image quality of the cardiac MR fluoroscopy technique were evaluated in 11 subjects. Compared with the conventional graphic prescription method, the cardiac fluoroscopy technique provides an approximate eightfold reduction in the time required to obtain subject-specific double oblique sections. Image quality for these scout acquisitions performed during free breathing was sufficient to identify small cardiac structures.

Coronary Angiography↗

PubMed1996

Fast CT for pulmonary embolus.

Recent technical advances in CT have led to the ability to scan a volume in a shorter period with optimal contrast opacification of blood vessels, including the pulmonary arteries. Initially, there were isolated instances of an accidental detection of a filling defect because of pulmonary embolus in the pulmonary arteries. Gradually, directed examinations were introduced to diagnose or exclude pulmonary embolus. These examinations were successful. Radiologists and clinicians now are turning to fast CT for this purpose for a variety of reasons, including the proven accuracy and reliability of the method and the relative deficiencies of traditional noninvasive methods. Accurate interpretation of CT scans for possible pulmonary embolus depends on the ability to conduct a high-quality examination and to recognize the spectrum of findings for both acute and chronic emboli. This article reviews the history of fast CT pulmonary angiography, and it presents both technical and diagnostic information germaine to the performance of this technique.

Acute Disease↗

PubMed1996

Electron beam computed tomography and coronary artery disease: scanning for coronary artery calcification.

OBJECTIVE: To review the association of coronary artery calcification with coronary atherosclerosis and its potential clinical application as detected on electron beam computed tomography (EBCT). DESIGN: A literature review of coronary artery calcification, coronary artery disease, and EBCT is presented, and clinical applications of EBCT are discussed. RESULTS: Recent studies have confirmed that arterial calcification is an active process intimately associated with atherosclerotic plaque evolution. Clinical investigations with use of EBCT have shown that a scan "negative" for coronary calcification is common in patients with normal or near-normal findings on coronary angiography, whereas patients with severe obstructive disease most commonly have "positive" scans--greater amounts of coronary artery calcium are associated with more severe luminal disease. Coronary artery calcium as evaluated on EBCT follows patterns that reflect the development of coronary atheromatous disease as a function of age and gender. Although histologic studies have confirmed that not all atherosclerotic segments have detectable calcification, the area of coronary artery calcification quantified on EBCT has a direct, positive relationship with the histopathologic coronary plaque area. CONCLUSION: The long-held notion of "degenerative" calcification of the coronary arteries with aging is incorrect. Although the incidence of coronary artery calcification increases with patient age, this relationship simply parallels the increased incidence of coronary atherosclerosis with advancing age. Data suggest that EBCT is a highly sensitive and specific test for coronary atherosclerosis and provide a basis for clinical applications when EBCT is viewed as a noninvasive method to estimate human coronary atherosclerotic involvement and "plaque burden."

Adult↗

PubMed1996

Ventricular remodeling after orthotopic cardiac transplantation.

OBJECTIVE: To determine quantitative changes in ventricular chamber volumes and left ventricular mass after orthotopic cardiac transplantation. MATERIAL AND METHODS: Right ventricular and left ventricular chamber volumes and left ventricular muscle mass were quantified by electron beam computed tomography in 10 patients at 1 month and 12 months after orthotopic cardiac transplantation. RESULTS: During the study period, the mean right ventricular end-diastolic volumes increased from 117 +/- 26.1 cc to 143 +/- 25.3 cc (P < 0.005), and the mean left ventricular end-diastolic volumes increased from 90 +/- 20.6 cc to 117 +/- 27.3 cc (P < 0.001). Left ventricular stroke volume increased from 63 +/- 16.5 cc at 1 month to 78 +/- 19.8 cc by 12 months (P < 0.005). These changes were associated with a concurrent reduction in global left ventricular muscle mass from 168 +/- 25.2 g to 145 +/- 16.3 g (P < 0.01). The left ventricular end-diastolic volume/mass ratio, an index of wall tension, was abnormally low at 1 month but was in the normal range by 12 months (P < 0.0005). Both left ventricular and right ventricular ejection fractions were normal at all times and not significantly changed between the 1-month and 12-month studies. CONCLUSION: Significant right and left ventricular remodeling occurs between 1 month and 12 months after orthotopic cardiac transplantation, with progressive cavity dilatation but reduction in global left ventricular muscle mass. These adjustments, especially in the left ventricle, tend to reduce the volume/mass ratio by 1 year and are compatible with normalization of ventricular wall tension between the early and late scan dates. Routine clinical measurements of ejection fraction alone mask the almost parallel increases in stroke volume and end-diastolic volume during the first 12 months after orthotopic cardiac transplantation.

Adult↗

PubMed1995

Coronary calcium, as determined by electron beam computed tomography, and coronary disease on arteriogram. Effect of patient's sex on diagnosis.

BACKGROUND: Coronary artery calcium identified by electron beam computed tomography (EBCT) has potential for noninvasive localization of coronary atherosclerotic disease. However, the effect of a patient's sex on its diagnostic capability has not been examined in a clinical population. METHODS AND RESULTS: Fifty women and 89 men had EBCT scans done an average of 1 day after coronary arteriography. Maximum arteriographic percent luminal diameter stenosis of any artery was paired with the total EBCT coronary calcium score for each subject. The women (age, 56 +/- 11 years [mean +/- SD]) were older than the men (age, 47 +/- 7 years), but the subjects were matched for indications for arteriography and extent of disease as assessed by arteriography. Sensitivity, specificity, and positive and negative predictive values for coronary calcium were nearly identical for men and women, regardless of the degree of arteriographic disease. EBCT was highly sensitive to the presence of arteriographic disease (range, 94% to 100%), but had only moderate specificity (57% to 66%) for significant disease (> or = 50% stenosis) and low specificity (35% to 38%) for any arteriographic disease (> 0% stenosis). Negative predictive values in men and women ranged from 79% to 91% for any arteriographic disease and from 95% to 100% for significant disease, respectively. Numerical calcium scores were significantly different between subjects with normal arteriograms and those with significant disease; however, calcium score had limited power to separate trivial, moderate, and significant disease. Receiver operating characteristic curve areas, determined as an extension of the analyses of sensitivity and specificity, were high for EBCT-defined calcium scores for both any arteriographic disease and significant arteriographic disease, and were not different between the sexes. CONCLUSIONS: In a middle-aged population, noninvasive definition of coronary calcium by EBCT has similar predictive value for arteriographic coronary artery disease in men and women.

Calcinosis↗

PubMed1995

Pulmonary embolism: diagnosis with contrast-enhanced electron-beam CT and comparison with pulmonary angiography.

PURPOSE: To determine the sensitivity and specificity of contrast material-enhanced electron-beam computed tomography (CT) in the diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: Sixty patients suspected of having PE were prospectively evaluated with pulmonary angiography and contrast-enhanced electron-beam CT. Thirty-eight patients underwent ventilation-perfusion (V-P [also known as V/Q]) scanning. The pulmonary vasculature was divided into 12 anatomic zones. CT and angiographic findings were correlated on a patient-by-patient basis and for each vascular zone. RESULTS: Both studies were negative for PE in 36 patients. Both studies were positive in 15 patients, with the site of the emboli correlating well. Prospective sensitivity of CT was 65%; specificity, 97%; positive predictive value, 94%; and negative predictive value, 82%. After review of the nine discordant cases, sensitivity and specificity approached 100% for clinically important acute PE. CT depicted central and peripheral emboli equally well. CT was more sensitive and specific than V-P scanning. CONCLUSION: Electron-beam CT is a sensitive and specific noninvasive method for the diagnosis of PE. It has the potential to replace V-P scanning as the primary screening examination for PE.

Humans↗

PubMed1995

Quantity of coronary artery calcium detected by electron beam computed tomography in asymptomatic subjects and angiographically studied patients.

OBJECTIVE: To determine the prevalence and quantity of coronary artery calcium (CAC) in asymptomatic subjects from the general population, to identify asymptomatic subjects without risk factors for coronary artery disease (CAD) with CAC scores in the top quartile of the distribution, and to compare CAC scores in patients who underwent angiography with percentiles in asymptomatic subjects of the same age and sex. DESIGN: We studied two samples from Rochester, Minnesota, which consisted of 772 asymptomatic subjects from the general population and 145 patients who underwent angiography, all of whom were 20 to 59 years of age. METHODS: Asymptomatic subjects were classified on the basis of their CAD risk profile. All subjects in both study samples underwent electron beam computed tomography. Age- and sex-specific calcium score percentiles were calculated in the asymptomatic sample. RESULTS: CAC prevalence in the asymptomatic subjects was lower in female than in male subjects and increased with advancing age. Of the asymptomatic sample, 8% had a low-risk profile with calcium scores in the top quartile of the distribution. More patients than expected in the angiography sample had calcium scores above the 50th through 95th score percentiles. CONCLUSION: The quantity of CAC was substantially increased in patients who underwent angiography. Subjects with large amounts of CAC but without known CAD risk factors may be a valuable subset of the population to investigate for previously unidentified CAD risk factors.

Adult↗

PubMed1994

Detection of heart calcification with electron beam CT: interobserver and intraobserver reliability for scoring quantification.

PURPOSE: To assess interobserver and intraobserver reliability of three quantitative measures of coronary artery calcium burden: calcium "score," number of calcified lesions, and calcified area. MATERIALS AND METHODS: Electron beam computed tomographic (CT) scanning was used in a series of 25 patients to detect coronary artery calcification. Scan results were reviewed for quality by a radiologist, then scored by two radiologic technologists and by another radiologist. RESULTS: Many interobserver and intraobserver disagreements were noted on a lesion-by-lesion basis. Since most disagreements involved very small lesions, however, their impact was negligible for all three measures of calcium burden. CONCLUSION: It is not useful for more than one observer to independently score a single CT examination obtained to detect cardiac calcification, even when the arteries are heavily calcified.

Adult↗

PubMed1994

Aprotinin for coronary bypass operations: efficacy, safety, and influence on early saphenous vein graft patency. A multicenter, randomized, double-blind, placebo-controlled study.

The purpose of this study was to evaluate the efficacy and safety of aprotinin in a U.S. population of patients undergoing coronary artery bypass grafting. Early vein graft patency rates were assessed by ultrafast computed tomography. A total of 216 patients at five centers were randomized to receive either high-dose aprotinin or placebo during the operation; 151 patients underwent primary operation, and 65 underwent repeat procedures. Total blood product exposures in the primary group were 2.2 per patient receiving aprotinin as compared with 5.7 per patient receiving placebo (p = 0.010). The repeat group had 0.3 exposures per patient receiving aprotinin as compared with 10.7 per patient receiving placebo (p = < 0.001). Consistent reductions in the percent of patients requiring donor red blood cells and in the number of units of platelets, fresh frozen plasma, and cryoprecipitate required were associated with the use of aprotinin in both primary and repeat groups. Mortality was 5.6% in the aprotinin group and 3.7% in the placebo group (p = 0.517). In the primary group, clinical diagnoses of myocardial infarction were made in 8.9% of patients receiving aprotinin as compared with 5.6% of the patients receiving placebo (p = 0.435). In the repeat group, infarctions occurred in 10.3% of patients receiving aprotinin and 8.3% of patients receiving placebo (p = 1.000). Secondary analysis of electrocardiograms and available enzyme data showed no significant difference in infarction rates between the treatment groups. There was no difference in clinically significant renal dysfunction. The early vein graft patency rates were 92.0% in the aprotinin group and 95.1% in the placebo group (p = 0.248). In this study, aprotinin was effective in reducing bleeding and blood product transfusion rates, and its use was not associated with an increase in complications. An adverse effect on early vein graft patency rates was not demonstrated, but the number of grafts assessed was insufficient for absolute conclusions in this regard.

Aprotinin↗

PubMed1993

Congenital partial and complete absence of the pericardium.

Between 1952 and 1991, 15 Mayo patients were found to have partial or complete absence of the pericardium at the time of a cardiovascular surgical procedure. One patient with complete absence of the left pericardium had symptoms possibly related to the pericardial abnormality. This 42-year-old man had severe insufficiency of the tricuspid valve attributable to chordal rupture of the anterior leaflet, possibly precipitated by complete displacement of the heart into the left pleural space. Excision of the ruptured chordae and plication of the anterior flail leaflet rendered a competent tricuspid valve. In two patients, a small defect in the pericardium was repaired. Three patients who underwent operation for complex congenital heart disease died: two early postoperatively and one late after a reoperation. In the other 12 patients, no early or late postoperative complications were encountered. Although rare and usually asymptomatic, complete and partial deficiency of the pericardium may lead to serious complications such as cardiac valvular insufficiency or incarceration of cardiac tissue.

Adult↗

PubMed1993

Ultrafast computed tomographic scanning to assess patency of coronary artery stents in bypass grafts.

Anginal chest pain after implantation of coronary stents in bypass grafts is a concern because it suggests the possibility of occlusion. Coronary angiography is the definitive method for determining patency of a stent; however, this procedure is relatively contraindicated in a patient receiving warfarin sodium, who has a therapeutic international normalized ratio. An alternative method for determining patency of a stent is by ultrafast computed tomography. This new, minimally invasive technique shows promise for determining blood flow within the large vessels of the thorax. Herein we describe a case in which a metallic stent placed in a vein graft was noninvasively established to be patent, despite chest pain in the patient. This method may be clinically applicable for determining patency of stents in vein grafts in the setting of patients with chest pain who have undergone complete anticoagulation.

Aged↗

PubMed1993

Right ventricular assessment in patients presenting for lung transplantation.

Chronic pulmonary disease is associated with varying degrees of cardiac dysfunction. Because of the potentially predominant effect of severe lung disease on right ventricular (RV) size and function, a reliable method to assess RV mechanics before and after lung transplantation may provide information of long-term significance and/or prognosis. Conventional invasive and non-invasive imaging methods have a number of limitations in evaluating RV function. Ultrafast computed tomographic (ultrafast CT) scanning has been shown to provide quantitative assessment of RV and left ventricular (LV) function in individuals with and without cardiac disease. Twenty-two patients presenting during evaluation for possible lung transplantation with end-stage pulmonary disease formed the basis of this study. There were 14 patients with chronic obstructive pulmonary disease and 8 with pulmonary fibrosis. Conventional transthoracic echocardiography and ultrafast CT were used for the assessment of RV and LV function. All patients had invasive assessment of right-sided hemodynamics and pulmonary function studies performed within 7-10 days of cardiac imaging. A qualitative assessment of RV size or function was possible in all but two patients by echocardiogram, but in 45%, the echocardiographic examination was described as suboptimal. In contrast, a quantitative assessment of ventricular volumes and systolic function was obtained in all patients by ultrafast CT. Pulmonary function parameters or hemodynamic measurements obtained during cardiac catheterization did not correlate with any assessment of RV function. We concluded that (1) ultrafast CT provides measurement of the RV and LV cavity dimension and systolic function; (2) invasive right-sided hemodynamics or pulmonary function studies do not predict RV function; and (3) echocardiography does not uniformly provide assessment of RV function in patients with chronic pulmonary disease.

Adult↗

PubMed1992

Noninvasive definition of anatomic coronary artery disease by ultrafast computed tomographic scanning: a quantitative pathologic comparison study.

OBJECTIVES: The aim of this study was to determine the relation between coronary artery calcification detected by ultrafast computed tomographic scanning and histopathologic coronary artery disease. BACKGROUND: Recent studies suggest that discrete coronary artery calcification as visualized by ultrafast computed tomographic scanning may facilitate the noninvasive detection or estimation, or both, of the in situ extent of coronary disease. Such quantitative relations have not been established. METHODS: Thirteen consecutive perfusion-fixed autopsy hearts (from eight male and five female patients aged 17 to 83 years) were scanned by ultrafast computed tomographic scanning in contiguous 3-mm tomographic sections. The major epicardial arteries were dissected free, positioned longitudinally and scanned again in cross section. Coronary artery calcification in a coronary segment was defined as the presence of one or more voxels with a computed tomographic density > 130 Hounsfield units. Each epicardial artery was sectioned longitudinally, stained and measured with a planimeter for quantification of cross-sectional and atherosclerotic plaque areas at 3-mm intervals, corresponding to the computed tomographic scans. A total of 522 paired coronary computed tomographic and histologic sections were studied. RESULTS: Direct relations were found between ultrafast computed tomographic scanning coronary artery calcium burden and atherosclerotic plaque area and percent lumen area stenosis. However, the range for plaque area or percent lumen stenosis, or both, associated with a given calcium burden was broad. Three hundred thirty-one coronary segments showed no calcification by computed tomography. Although atherosclerotic disease was found in several corresponding pathologic specimens, > 97% of these noncalcified segments were associated with nonobstructive disease (< 75% area stenosis); if no calcification was determined in an entire coronary vessel, all corresponding coronary disease was found to be nonobstructive. To determine the relation between arterial calcification and any atheromatous disease, computed tomographic calcium burden for each segment was paired with the histologic absence or presence of disease. Ultrafast computed tomographic scanning had a sensitivity and specificity of 59% and 90% and a negative and positive predictive value of 65% and 87%, respectively. A direct correlation was found (r = 0.99) between total calcium burden calculated from tomographic scans of the heart as a whole and scans of the arteries obtained in cross section. CONCLUSIONS: The detection of coronary calcification by ultrafast computed tomographic scanning is highly predictive of the presence of histopathologic coronary disease, but the use of this technique to define the extent of coronary disease may be limited. However, the absence of coronary calcification at any site is highly specific for the absence of obstructive disease.

Adolescent↗

PubMed1992

Coronary artery calcification detected with ultrafast CT as an indication of coronary artery disease.

To assess the relationship of coronary artery calcification to angiographically detectable disease, the authors evaluated 100 patients less than 60 years of age who underwent clinically indicated coronary angiography and ultrafast computed tomography (CT). The ultrafast CT technique consisted of 3-mm-thick contiguous sections and a 100-msec acquisition time. All patients with clinically significant disease at angiography (defined as at least one stenosis with a diameter narrowing of at least 50%) had some coronary artery calcification present at ultrafast CT (100% sensitivity in this population). The absence of calcification at ultrafast CT had a 100% negative predictive value for clinically significant coronary artery disease. Specificity and positive predictive value were 47% and 62%, respectively. Sensitivity and specificity of ultrafast CT in the detection of patients with angiographically detectable disease were 94% and 72%, respectively. Ultrafast CT of the heart is an anatomically based, noninvasive test with high sensitivity for the detection of coronary artery calcification. Ultrafast CT may be beneficial in the screening of selected populations for the presence of atherosclerotic coronary disease.

Adult↗

PubMed1990

Modification by sialic acid of Neisseria gonorrhoeae lipooligosaccharide epitope expression in human urethral exudates: an immunoelectron microscopic analysis.

Expression of lipooligosaccharide (LOS) antigenic determinants during human gonococcal infection was studied in secretions from seven men with gonococcal urethritis. Five monoclonal antibodies with distinct gonococcal LOS specificities and an H.8 lipoprotein monoclonal antibody were used in combination with immunogold electron microscopic analysis. The LOS epitope defined by antibody 6B7 was present on all seven strains in secretions and after in vitro growth. Gonococci from six of seven patients, when grown in vitro, expressed the 6B4 LOS epitope. The 6B4 epitope is a Gal beta 1-4-GlcNAc residue, which is immunochemically similar to the precursor of the human erythrocyte i antigen. This epitope was found unmodified on gonococcal LOS in urethral secretions from two patients. The unmodified epitope could not be demonstrated on organisms in five secretions. Neuraminidase digestion exposed the 6B4 epitope on organisms in these secretions and increased the 6B4 epitope density in the two secretions, which contained the unmodified epitope. These studies indicate that in vivo modification by sialylation of gonococcal LOS Gal beta 1-4-GlcNAc residue occurs during human infection.

Antibodies, Monoclonal↗

PubMed1990

Monorail system for percutaneous repositioning of the Greenfield vena caval filter.

The authors describe a technique for removing or repositioning a malpositioned Greenfield inferior vena caval filter. A "monorail" system was used, in which a wire was passed from the femoral vein through the apical hole in the filter and out the internal jugular vein; the wire was held taut from above and below and thus facilitated repositioning or removal of the filter. The technique was used successfully in two cases.

Adult↗