Biomedical subjects

James W Sayre

Publications and source records attributed to James W Sayre.

15 recordsLinked to original sources

PubMed2006

Evidence of publication bias in reporting acute stroke clinical trials.

OBJECTIVE: To ascertain the extent of publication bias in the reporting of acute stroke clinical trials. METHODS: We identified controlled acute ischemic stroke clinical trials reported in English over a 45-year period from 1955 to 1999 through systematic search of MEDLINE, the Cochrane Controlled Stroke Trials Register, and additional databases. We analyzed trial methodology, quality, outcome, study sponsorship, and timing of publication to identify various forms of publication bias, including nonpublication bias, abbreviated publication bias, and time-lag bias. RESULTS: One hundred seventy-eight acute ischemic stroke trials, enrolling 73,949 subjects, evaluated 75 agents or nonpharmacologic interventions. A greater proportion of harmful outcomes in unpublished studies (n = 4) compared with published trials (0.75 vs 0.06, p < 0.0001) and underreporting of smaller, nonbeneficial studies in acute stroke suggest nonpublication bias. Although a definite time-lag bias was not evident, nonbeneficial studies were slower to proceed from enrollment completion to publication (2.3 vs 2.0 years, p = 0.207), with an even longer delay for nonbeneficial corporate pharmaceutical sponsored trials (2.8 vs 2.1 years, p = 0.086), despite superior trial report quality scores for corporate-sponsored studies when compared with nonprofit/governmental studies (mean 69.2 +/- 95% CI 3.9 vs 53.4 +/- 95% CI 9.2, p < 0.005). CONCLUSION: Publication bias is evident in the acute stroke research literature, supporting the need for prospective trial registration.

Chi-Square Distribution↗

PubMed2005

Quantitative analysis of the corpus callosum in children with cerebral palsy and developmental delay: correlation with cerebral white matter volume.

BACKGROUND: The direct quantitative correlation between thickness of the corpus callosum and volume of cerebral white matter in children with cerebral palsy and developmental delay has not been demonstrated. OBJECTIVE: This study was conducted to quantitatively correlate the thickness of the corpus callosum with the volume of cerebral white matter in children with cerebral palsy and developmental delay. MATERIAL AND METHODS: A clinical database of 70 children with cerebral palsy and developmental delay was established with children between the ages of 1 and 5 years. These children also demonstrated abnormal periventricular T2 hyperintensities associated with and without ventriculomegaly. Mid-sagittal T1-weighted images were used to measure the thickness (genu, mid-body, and splenium) and length of the corpus callosum. Volumes of interest were digitized based on gray-scale densities to define the hemispheric cerebral white matter on axial T2-weighted and FLAIR images. The thickness of the mid-body of the corpus callosum was correlated with cerebral white matter volume. Subgroup analysis was also performed to examine the relationship of this correlation with both gestational age and neuromotor outcome. Statistical analysis was performed using analysis of variance and Pearson correlation coefficients. RESULTS: There was a positive correlation between the thickness of the mid-body of the corpus callosum and the volume of cerebral white matter across all children studied (R=0.665, P=0.0001). This correlation was not dependent on gestational age. The thickness of the mid-body of the corpus callosum was decreased in the spastic diplegia group compared to the two other groups (hypotonia and developmental delay only; P<0.0001). Within each neuromotor subgroup, there was a positive correlation between thickness of the mid-body of the corpus callosum and volume of the cerebral white matter. CONCLUSION: The thickness of the mid-body of the corpus callosum positively correlates with volume of cerebral white matter in children with cerebral palsy and developmental delay, regardless of gestational age or neuromotor outcome. Assessment of the thickness of the corpus callosum might help in estimating the extent of the loss of volume of cerebral white matter in children with a broad spectrum of periventricular white matter injury.

Agenesis of Corpus Callosum↗

PubMed2005

Coronary circulatory dysfunction in insulin resistance, impaired glucose tolerance, and type 2 diabetes mellitus.

BACKGROUND: Abnormal coronary endothelial reactivity has been demonstrated in diabetes and is associated with an increased rate of cardiovascular events. Our objectives were to investigate the presence of functional coronary circulatory abnormalities over the full spectrum of insulin resistance and to determine whether these would differ in severity with more advanced states of insulin resistance. METHODS AND RESULTS: Myocardial blood flow (MBF) was measured with positron emission tomography and 13N-ammonia to characterize coronary circulatory function in states of insulin resistance without carbohydrate intolerance (IR), impaired glucose tolerance (IGT), and normotensive and hypertensive type 2 diabetes mellitus (DM) compared with insulin-sensitive (IS) individuals. Indices of coronary function were total vasodilator capacity (mostly vascular smooth muscle-mediated) during pharmacological vasodilation and the nitric oxide-mediated, endothelium-dependent vasomotion in response to cold pressor testing. Total vasodilator capacity was similar in normoglycemic individuals (IS, IR, and IGT), whereas it was significantly decreased in normotensive (-17%) and hypertensive (-34%) DM patients. Compared with IS, endothelium-dependent coronary vasomotion was significantly diminished in IR (-56%), as well as in IGT and normotensive and hypertensive diabetic patients (-85%, -91%, and -120%, respectively). CONCLUSIONS: Progressively worsening functional coronary circulatory abnormalities of nitric oxide-mediated, endothelium-dependent vasomotion occur with increasing severity of insulin-resistance and carbohydrate intolerance. Attenuated total vasodilator capacity accompanies the more clinically evident metabolic abnormalities in diabetes.

Adult↗

PubMed2005

Solitary pulmonary nodule diagnosis on CT: results of an observer study.

RATIONALE AND OBJECTIVES: To investigate the performance of observers with different levels of experience in distinguishing between benign and malignant solitary pulmonary nodules (SPN) on CT, and to determine the effects on interpretation of three different conditions: image data alone, the addition of clinical data, and the addition of output from a computer-aided diagnosis (CAD) system. MATERIALS AND METHODS: 28 thin-section CT datasets of SPNs with proven diagnoses (15 malignant and 13 benign) were used to measure observer performance. Readers were categorized according to their experience and read the cases in random order. For each case readers were asked to assign a level of confidence on a scale from 0.0-1.0 (0.0 benign, 1.0 malignant) for the diagnosis of the nodule. Each reader scored the cases based on review of image data alone (phase 1), then with limited clinical data (phase 2), and finally with CAD output (phase 3). To assess performance, multiple reader multiple case (MRMC) receiver operating characteristic (ROC) analysis was used. RESULTS: 2 thoracic radiologists, 1 thoracic radiology fellow, 2 nonthoracic radiologists, and 3 radiology residents read the cases. The average area under the ROC curve for all readers (A(z)) at each stage was 0.68, 0.75, and 0.81, for image data alone, with clinical data, and with CAD output respectively. The difference in performance between phases (2 and 3) and (1 and 3) was significantly different (P = 0.018 and P = 0.020). However, the difference between phases (1 and 2) was not significantly different (P = 0.155). CONCLUSION: Diagnostic performance increased significantly with the addition of CAD output. With further validation CAD output may play a significant role in SPN management.

Diagnosis, Computer-Assisted↗

PubMed2005

Computer-aided diagnosis of the solitary pulmonary nodule.

RATIONALE AND OBJECTIVES: We sought to investigate the utility of a computer-aided diagnosis in the task of differentiating malignant nodules from benign nodules based on single thin-section computed tomography image data. MATERIALS AND METHODS: Eighty-one thin-section computed tomography data sets of solitary pulmonary nodules with proven diagnoses (48 malignant and 33 benign) were contoured manually on a single representative slice by a thoracic radiologist (>10 years of experience). Two separate contours were created for each nodule, one including only the solid portion of the nodule and one including any ground-glass components. For each contour 75 features were calculated that measured the attenuation, shape, and texture of the nodule. These features were than input into a feature selection step and four different classifiers to determine if the diagnosis could be predicted from the feature vector. Training and testing was conducted in a resubstitution and leave-one-out fashion and performance was evaluated using ROC techniques. RESULTS: In a leave-one-out testing methodology the classifiers resulted with areas under the ROC curve (A(Z)) that ranged from 0.68 to 0.92. When evaluating with resubstitution the A(Z) ranged from 0.93 to 1.00. CONCLUSION: Computer-aided diagnosis has the potential to assist radiologists in the task of differentiating solitary pulmonary nodules and in the management of these patients.

Diagnosis, Differential↗

PubMed2005

Computer-aided lung nodule detection in CT: results of large-scale observer test.

RATIONALE AND OBJECTIVES: The objective is to study the incremental effects of using a computer-aided lung nodule detection (CAD) system on the performance of a large pool of observers. MATERIALS AND METHODS: A set of eight thin-section computed tomographic data sets with limited longitudinal coverage, containing a total of 22 lung nodules, was analyzed by using the automated nodule detection system. When applied to all eight cases, the CAD system alone achieved a detection rate of 86.4%, with 2.64 false-positive results per case. This study included 202 observers at a national radiology meeting: 39 thoracic radiologists, 95 non-thoracic radiologists, and 68 non-radiologists. Each participant read from one to eight cases in random order, first without and then with CAD system output available. Observer performance in nodule detection was measured before and after CAD was made available. Differences in performance of groups of observers before and after CAD were tabulated by mean, median, and SD in detection rate and number of false-positive results and tested by using nonparametric methods. RESULTS: In an analysis involving only the first randomly selected case read by all 202 participants, there were statistically significant increases in nodule detection rates and numbers of false-positive results for all types of observers. There was a significant difference in detection rates between radiologists and non-radiologists before CAD, but after CAD, there was no significant difference in detection rates between these observer types. In a second analysis involving 13 participants who read all eight cases, mean detection rates were 64.0% before CAD and 81.9% after CAD. Mean numbers of false-positive results were 0.144 per case before CAD and 0.173 after CAD. CONCLUSION: In a large observer study, use of a CAD system for nodule detection resulted in an incremental increase in detection rate, but also led to an increase in number of false-positive results. Also, CAD appears to be an equalizer of detection rates between observers of different levels of experience.

Clinical Competence↗

PubMed2005

Computer aided characterization of the solitary pulmonary nodule using volumetric and contrast enhancement features.

RATIONALE AND OBJECTIVES: To investigate the utility of a computer-aided diagnosis (CAD) in the task of differentiating malignant nodules from benign nodules based on quantitative features extracted from volumetric thin section CT image data acquired before and after the injection of contrast media. MATERIALS AND METHODS: 35 volumetric CT datasets of solitary pulmonary nodules (SPN) with proven diagnoses (19 malignant/16 benign) were contoured by a thoracic radiologist. All studies had at least a baseline series obtained without contrast media and at least one series following an intravenous contrast injection at 45, 90, 180, and 360 seconds. Two separate contours were created for each nodule: one including only the solid portion and another including the ground-glass component, if any, of the nodule. For each contour 31 features were calculated that measured the attenuation, shape, and enhancement of the nodule due to the injection of contrast. These features were input into a feature selection step and three different classifiers to determine if the diagnosis could be predicted from the resulting feature vector. In addition, observer input was introduced to two of the classifiers as an a priori probability of malignancy and the resulting performance was compared. Training and testing was conducted in a resubstitution and leave-one-out fashion and performance was evaluated using ROC analysis. RESULTS: In a leave-one-out testing methodology, the classifiers achieved areas under the ROC curves AZ that ranged from 0.69 to 0.92. A classifier based on logistic regression performed the best with an AZ of 0.92 while a classifier based on quadratic discriminant analysis performed the poorest (AZ, 0.69). The AZ increased when using a priori observer input in most cases reaching a maximum of 0.95. CONCLUSION: Based on this initial work with a limited number of nodules in our dataset, it appears that CAD using volumetric and contrast-enhanced data has the potential to assist radiologists in the task of differentiating solitary pulmonary nodules and in the management of these patients. Further studies with an increased number of patients are required to validate these results.

Adult↗

PubMed2005

Utility of breath-hold fast-recovery fast spin-echo t2 versus respiratory-triggered fast spin-echo T2 in clinical hepatic imaging.

OBJECTIVE: The objective of our study was to compare a breath-hold fat-suppressed fast-recovery fast spin-echo (FSE) T2-weighted sequence with a respiratory-triggered fat-suppressed FSE T2-weighted sequence to assess the effect on image quality and lesion detection and characterization in clinical hepatic imaging. MATERIALS AND METHODS: Both the breath-hold fat-suppressed fast-recovery FSE and respiratory-triggered fat-suppressed FSE T2-weighted sequences were acquired in 46 patients. Two radiologists, blinded to clinical data, independently evaluated randomized images from both sequences. Qualitatively, images were graded on a 5-point scale for five different characteristics. The number and location of lesions were recorded. The confidence of detection and the confidence of characterization (solid vs nonsolid) were graded on a 5-point scale. A consensus review using radiology, clinical, and pathology data served as the standard. Receiver operating characteristic (ROC) curve analysis (area under the ROC curve [A(z)]) was used to compare each reviewer's interpretation against the consensus interpretation. Quantitative analysis was performed by calculating the liver signal-to-noise ratio (SNR), liver-to-spleen contrast-to-noise ratio (CNR), and lesion-to-liver CNR. Both one- and two-tailed Student's t tests were used to check for significance. RESULTS: Qualitatively, both reviewers graded the breath-hold fat-suppressed fast-recovery FSE T2-weighted sequence better than the respiratory-triggered fat-suppressed FSE T2-weighted sequence on all five characteristics (p < 0.005). Of 78 lesions detected, 29 were characterized as solid; 47, nonsolid; and two, indeterminate. On ROC analysis, there were no significant differences between the breath-hold fat-suppressed fast-recovery FSE and respiratory-triggered fat-suppressed FSE T2-weighted sequences in lesion detection (A(z) reviewer 1, 0.77 and 0.83, respectively, [p = 0.12]; A(z) reviewer 2, 0.84 and 0.80, respectively [p = 0.12]) or in lesion characterization (A(z) reviewer 1, 0.86 and 0.92, respectively [p = 0.33]; A(z) reviewer 2, 0.90 and 0.91, respectively [p = 0.79]). Quantitatively, liver SNRs, spleen CNRs, and lesion CNRs (solid and nonsolid lesions) were significantly better on the breath-hold fat-suppressed fast-recovery FSE T2-weighted images than on the respiratory-triggered fat-suppressed FSE T2-weighted images (p < 0.005). CONCLUSION: Breath-hold fat-suppressed fast-recovery FSE T2-weighted images were of better quality than respiratory-triggered fat-suppressed FSE T2-weighted images, and lesion detection and characterization were comparable.

Adult↗

PubMed2004

Breast core-needle biopsy: clinical trial of relaxation technique versus medication versus no intervention for anxiety reduction.

PURPOSE: To evaluate effectiveness of oral anxiolytic medication versus relaxation technique for anxiety reduction in women undergoing breast core-needle biopsy (CNB). MATERIALS AND METHODS: The institutional review board reviewed and approved the study. Informed consent was obtained from 143 consecutive women scheduled for breast CNB. Women were randomized as follows: no anxiety intervention (usual care group), relaxation therapy with an audiotape of classical music and ocean sounds during CNB (relaxation group), and 0.5-mg of alprazolam administered orally 15 minutes before CNB (medication group). Anxiety before, during, and 24 hours after the procedure was assessed with State-Trait Anxiety Inventory and self-reported visual analog scale from 0 (no anxiety) to 10 (worst anxiety). Data analysis was performed with statistical software. Descriptive statistics were computed for all variables. Group differences were determined with analysis of variance. Differences in mean values were assessed with Bonferroni multiple comparison procedure. Categorical demographic differences were assessed with chi(2) statistic. RESULTS: Preprocedural State-Trait Anxiety Inventory scores indicated that women were not inherently anxious: usual care group, score of 44.63; relaxation group, 45.74; and medication group, 49.1. Scores represented significantly elevated anxiety for women in all three groups when compared with the normative value of 35.12 (P < .0001), with no statistically significant differences between the scores of the three groups. Women in medication group reported significant reductions in anxiety (-44%) from levels determined before the procedure to levels determined during the procedure (P = .02) and significant reduction during the procedure when compared with changes in usual care (+15%) and relaxation (-8%) groups (P = .02). Women in all three groups reported significant reduction in anxiety from levels determined before the procedure to levels determined at 24 hours after it (P < .0001). There was no significant difference (P = .95) in 24-hour postprocedural anxiety levels among the three groups. CONCLUSION: Use of oral anxiolytic medication before breast CNB can significantly reduce anxiety women experience during the procedure.

Adult↗

PubMed2003

Supervision of residents by faculty radiologists using home workstations.

Our purpose was to determine if a home-based faculty radiologist equipped with a high-resolution workstation could add new information to residents' readings on overnight computed chest images that was equivalent to the new information generated by faculty reviewers inside the hospital. Teleconferencing software was installed on home workstations for online supervision of residents by faculty on chest images from a cardiothoracic intensive care unit. Critical observations that could affect patient care were recorded by first-year radiology residents before and after teleconferencing with the home-based radiologist. The amount of information added was compared with that which was added on the same 50 images through direct consultations with faculty inside the medical center. The amount of critical information that was added by teleconferencing with a chest radiologist at home was equivalent statistically to the information added through direct supervision of residents by faculty inside the hospital. Teleconferencing resulted in 149 changes in critical image findings as reported initially by the residents, out of 800 possible findings on 50 chest images, as opposed to 142 changes in residents' readings by faculty inside the medical center. Faculty subspecialists can supervise radiology residents effectively from their homes after hours, using high-resolution workstations and special teleconferencing software.

Journal Article↗

PubMed2003

Survey of radiology residents: breast imaging training and attitudes.

PURPOSE: To investigate the training and attitudes of residents regarding breast imaging. MATERIALS AND METHODS: A telephone survey was conducted with 201 4th-year residents (postgraduate medical school year 5) and 10 3rd-year residents (postgraduate medical school year 4) at 211 accredited radiology residencies in the United States and Canada. Survey topics included organization of the breast imaging section, residents' role in the section, clinical practice protocols of the training institution, residents' personal thoughts about breast imaging, and their interest in performing breast imaging in the future. RESULTS: Of 211 programs, 203 (96%) had dedicated breast imaging rotations; 196 (93%) rotations were 8 weeks or longer; 153 (73%), 12 weeks or longer. Residents dictated reports in 199 (94%) programs. Residents performed real-time ultrasonography (US) in 186 (88%) programs, needle localization in 199 (94%), US-guided biopsy in 174 (82%), and stereotactically guided biopsy in 181 (86%). One hundred eighty-four (87%) residents rated interpretation of mammograms more stressful than they did that of other images, and 137 (65%) believed mammograms should be interpreted by subspecialists. One hundred thirty-five (64%) residents would not consider a fellowship in breast imaging if offered, and 133 (63%) would not want to spend 25% or more of their time in clinical practice on interpretation of mammograms. The most common reasons given for not considering a fellowship or interpretation of mammograms were that breast imaging was not an interesting field, that they feared lawsuits, and that it was too stressful. Fellowships were offered at 53 programs, and at 46 programs, a total of 63 fellows were recruited. CONCLUSION: Residency training in breast imaging has improved in terms of time and curriculum. However, a majority of the residents would not consider a fellowship and did not want to interpret mammograms in their future practices.

Attitude of Health Personnel↗

PubMed2003

Lung micronodules: automated method for detection at thin-section CT--initial experience.

An automated system was developed for detecting lung micronodules on thin-section computed tomographic images and was applied to data from 15 subjects with 77 lung nodules. The automated system, without user interaction, achieved a sensitivity of 100% for nodules (>3 mm in diameter) and 70% for micronodules (<or=3 mm). With the same images, a radiologist detected nodules and micronodules with sensitivities of 91% and 51%, respectively, without system input. With assistance from the automated system, these sensitivities increased to 95% and 74%, respectively. Preliminary results indicate that the automated system considerably improved the radiologist's performance in micronodule detection.

Aged↗

PubMed2002

Noninvasive assessment of coronary microcirculatory function in postmenopausal women and effects of short-term and long-term estrogen administration.

BACKGROUND: Estrogen improves endothelial function in the coronary conduit vessels of animals; however, its effects on the coronary microcirculation have not been studied completely in humans. METHODS AND RESULTS: We measured myocardial blood flow (MBF) with a PET scan at rest, during cold pressor testing (CPT), and during dipyridamole hyperemia in 54 postmenopausal women without coronary artery disease. Of these, 23 were not and 31 women were taking long-term hormone replacement therapy (HRT) using estrogen either alone or with a progestogen. Each group was subdivided by coronary risk factors (RFs). Twelve young healthy women served as controls. In women not taking HRT, MBF measurements were repeated after 25 mg of conjugated equine estrogens IV. Neither short estrogen nor long-term HRT affected MBF at rest in women with and without RFs. Dipyridamole MBF was attenuated only in the women with RF who were not taking HRT. Short-term estrogen and long-term HRT did not reverse the abnormal response. MBF responses to CPT were abnormal in women not taking HRT, regardless of RFs (20+/-15% versus 32+/-21%) and remained unchanged after short-term estrogen administration. Long-term HRT normalized the response to CPT only in women without RF (53+/-22% versus 59+/-36% in the young women; NS). MBFs were similar for women on estrogen alone or estrogen plus a progestogen, regardless of presence or absence of RFs. CONCLUSION: Menopause is associated with abnormal CPT (an indirect measure of endothelial function), which can be reversed by long-term HRT only when RFs are absent. Progestogens do not antagonize this effect. Long-term HRT may therefore be useful in the primary prevention of coronary artery disease in women without RFs.

Adult↗

PubMedDate not supplied

Mammography with breast cushions.

OBJECTIVE: We conducted a randomized clinical trial to determine the impact on pain and image quality when breast cushions were used to pad the surfaces of the mammography equipment during film-screen mammography. METHODS: We recruited a consecutive volunteer sample of 394 participants. Breast cushions were used for only one breast, with laterality and sequence of use assigned randomly. Data collected from participants included demographic data, rating of pain from previous mammography, and rating of pain from present mammography using both a numeric rating scale and a visual analogue scale. Research assistants also collected breast compression and radiation exposure data. Radiologists were blinded to the laterality of cushion assignment while reading the mammograms and assessing image quality. RESULTS: Participants were primarily white women (75.3%), mean age 55.4 years. Most (94.4%) reported having previous mammography. Eight percent (n = 32) of those surveyed had thought about skipping or delaying mammography because of the pain involved. The pain associated with mammography was significantly (p < .001) less during oblique and craniocaudal views when breast cushions were used during the procedure. Retakes were required for 2% of the 1576 views with the most common reason being positioning (53%). CONCLUSION: The use of breast cushions significantly reduced the pain during film-screen mammography. Image quality with the cushions was reduced in a very small subset of women probably due to the difficulty in positioning the breast without visual clues. More research needs to be done prior to the routine use of these cushions in clinical practice.

Adult↗

PubMedDate not supplied

Reduction of discomfort during mammography utilizing a radiolucent cushioning pad.

The purpose of this study was to evaluate the use of a radiolucent cushioning pad during routine screening mammography to determine the degree of reduction in discomfort, any correlation of that reduction with various clinical factors, and the pad's impact on image quality, compression force, and radiation dose. A total of 512 patients presenting for routine screening mammography were evaluated. The radiolucent cushioning pads (MammoPad, Biolucent Inc., Aliso Viejo, CA) were placed on the bucky and compression paddle of the mammographic equipment (M-IV, Lorad Corp., Danbury, CT). For each patient, the radiolucent pads were used for imaging one breast while the opposite breast, which served as a control, was imaged without the pads. In all patients, the breast was positioned and compressed in standard fashion, using routine craniocaudal (CC) and mediolateral oblique (MLO) views. Patients completed a questionnaire before and after the mammogram. A visual analog scale (VAS) was used to record anticipated discomfort as well as the discomfort experienced during compression with and without the pads. Age, hormone replacement status, prior experience with mammography, compression force, and breast composition were recorded, as were dose parameters (mAs and kVp), from which midglandular dose values were calculated. On the side where the pads were used to cushion the breast, 73.5% (371/505) of women experienced a significant decrease in discomfort. Of those who benefited, there was a 47% decrease in discomfort. On the pad side, compression force was increased an average of 14%, and there was a 4% decrease in dose for the CC view and no increase in dose for the MLO view. When comparing benefit versus nonbenefit groups, a significant reduction in discomfort did not correlate with any of the clinical factors evaluated, with the exception of experienced discomfort reported after the mammogram. Use of the MammoPad radiolucent cushion on the bucky and compression paddle was an effective means of reducing discomfort during compression for a majority (73.5%) of our patients undergoing screening mammography. Image quality and the ability to detect all pertinent anatomy were maintained.

Breast Neoplasms↗