Technology anxiety as a potential mediating factor in response to medical technology

Technology anxiety, defined as a fear of working with medical equipment, was measured via the use of the Technology Response Questionnaire. Nurses (N=414) working on nine types of nursing units at two hospitals participated in the study. Nurses working on psychiatric units were found to be most anxious about working with medical equipment, while nurses working on surgical and adult intensive care units were least anxious. A comparison of the nurses who were highest and lowest on technology anxiety indicated that those who were most anxious about technology were less positive toward computers, felt more stressed by their work, were lower on job satisfaction, less positive toward the physicians they worked with, lower on personality scales of autonomy and adaptability, were less likely to do care planning regularly or to use nursing diagnoses, and tended to be older than less anxious nurses.     

Contrast Limited Adaptive Histogram Equalization image processing to improve the detection of simulated spiculations in dense mammograms

The purpose of this project was to determine whether Contrast Limited Adaptive Histogram Equalization (CLAHE) improves detection of simulated spiculations in dense mammograms. Lines simulating the appearance of spiculations, a common marker of malignancy when visualized with masses, were embedded in dense mammograms digitized at 50 micron pixels, 12 bits deep. Film images with no CLAHE applied were compared to film images with nine different combinations of clip levels and region sizes applied. A simulated spiculation was embedded in a background of dense breast tissue, with the orientation of the spiculation varied. The key variables involved in each trial included the orientation of the spiculation, contrast level of the spiculation and the CLAHE settings applied to the image. Combining the 10 CLAHE conditions, 4 contrast levels and 4 orientations gave 160 combinations. The trials were constructed by pairing 160 combinations of key variables with 40 backgrounds. Twenty student observers were asked to detect the orientation of the spiculation in the image. There was a statistically significant improvement in detection performance for spiculations with CLAHE over unenhanced images when the region size was set at 32 with a clip level of 2, and when the region size was set at 32 with a clip level of 4. The selected CLAHE settings should be tested in the clinic with digital mammograms to determine whether detection of spiculations associated with masses detected at mammography can be improved.Key Words: mammography, image processing, contrast limited adaptive histogram equalization, observer studies, breast cancer, spiculations     

Observer variability in the pulmonary examination

Observer variability in the pulmonary examination was assessed by having four blindfolded observers (two medical students and two pulmonary physicians) twice examine 31 patients with abnormal pulmonary findings. Examiners were consistent in the repetitive detection of pulmonary abnormalities in 74–89% of the examinations; conversely, 11–26% of the time they disagreed with themselves. Although pulmonary specialists recorded fewer (55% of observations) abnormal findings than did medical students (74%), they were significantly (p=0.008) less self-consistent than were the students. There was no clear trend in agreement between examiners (kappa=0.20−0.49). Each examiner’s findings were compared with those of physicians specially trained in pulmonary examination. Dichotomous variables (wheezes, crackles, rubs) were more reliably detected (kappa=0.30−0.70) than graded variables (tympany, dullness, breath sound intensity), where kappa=0.16−0.43. The authors suggest that dichotomous variables deserve greatest clinical reliance; that time in training, alone, does not improve clinical performance; and that there is a disconcertingly large amount of inter- and intraobserver disagreement in this fundamental clinical task. Received from the Division of General Internal Medicine, Department of Medicine; the Division of Biometry, Department of Community and Family Medicine, Duke University Medical Center, Durham, North Carolina; and the Ambulatory Care Service and Health Services Research Field Program, Durham V.A. Medical Center, Durham, North Carolina.     

Characterizing His-Purkinje system signals observed at the body surface. A model study

A computer model of the His-Purkinje system (HPS), based on human geometry, has been developed and used in conjunction with an atrial model and an inhomogeneous torso model to calculate electrocardiograms (ECGs) and isofield potential and magnetic maps. The calculated electric potential maximum for penetrating His bundle (HB) activity is 0.6 microV, somewhat smaller than reported by others. A calculated ECG of combined atrial and HPS activity indicates that atrial repolarization contributes to the ramp pattern observed in the PR segment. Simulated isofield distributions indicate two features that should be present in serial-measured HPS maps: (1) maps preceding HB activity should be included to illustrate the nature of the onset of HB activity and (2) maps should show a change in the location and magnitude of the extrema commensurate with the change in direction and magnitude of the source current circumscribed by the anatomy of the HB and bundle branches.     

Stereotactic and sonographic large-core biopsy of nonpalpable breast lesions: results of the Radiologic Diagnostic Oncology Group V study

RATIONALE AND OBJECTIVES: To determine the diagnostic accuracy of stereotactically and sonographically guided core biopsy (CB) for the diagnosis of nonpalpable breast lesions. MATERIALS AND METHODS: Twenty-two institutions enrolled 2,403 women who underwent imaging-guided fine needle aspiration followed by imaging-guided large-CB of nonpalpable breast abnormalities. All mammograms were reviewed for study eligibility by one of two breast imaging radiologists. The protocol for image-guided biopsy, using either ultrasound (USCB) or stereotactic (SCB) guidance, was standardized at all institutions and all biopsy specimens were over-read by one of three expert pathologists. Patients with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia, or lobular neoplasia on CB underwent surgical excision. Those with negative CB but suspicious ("discordant") pre-biopsy mammography also underwent surgical excision. Patients having a negative CB that was concordant with the pre-biopsy mammography suspicion were assigned to follow-up mammography at 6, 12, and 24 months following CB. RESULTS: A gold standard diagnosis based on definitive histopathologic diagnosis, mammography follow-up, or an imputed gold standard diagnosis was established for 1,681 patients. Of 310 cases with a gold standard diagnosis of invasive breast carcinoma, 261 (84.2%) were invasive carcinoma, 31 (10%) were ductal carcinoma in situ (DCIS), four (1.3%) were ADH, one (0.3%) was a non-breast cancer, and 13 (4.2%) were benign on CB. For 138 cases with a gold standard diagnosis of DCIS, 113 (81.9%) were DCIS, 20 (14.5%) were ADH, and five (3.6%) were benign on CB. For 57 cases (13 masses, 44 calcifications) with an initial CB diagnosis of ADH, atypical lobular hyperplasia or lobular neoplasia, 20 (35.1%) had a gold standard diagnosis of DCIS (4 masses, 16 calcifications) and four (7.0%) had a gold standard diagnosis of invasive cancer (4 calcifications). Of 144 cases (22 masses, 122 calcifications) with an initial CB diagnosis of DCIS, 31 (21.5%) had a gold standard diagnosis of invasive cancer (10 masses, 21 calcifications). The sensitivity, specificity and accuracy for CB by either imaging guidance method in this trial were .91, 1.00, and .98, respectively. The sensitivity, predictive value negative, and accuracy of CB for diagnosing masses (.96, .99, and .99, respectively) were significantly greater (P < .001) than for calcifications (.84, .94, and .96, respectively). The sensitivity (.89) of SCB for diagnosing all lesions was significantly lower (P = 0.029) than that of USCB (.97) because of the preponderance of calcifications biopsied by SCB versus USCB. There was no difference between USCB and SCB in sensitivity, predictive value negative, or accuracy for the diagnosis of masses (97.3, 98.9, and 99.2, respectively for USCB; 95.6, 98.5, and 98.9 respectively for SCB). CONCLUSION: Percutaneous, imaged-guided core breast biopsy is an accurate diagnostic alternative to surgical biopsy in women with mammographically detected suspicious breast lesions.     

Online annotation tool for digital mammography

RATIONALE AND OBJECTIVES: To develop a software tool for radiologists to annotate mammograms online. MATERIALS AND METHODS: The tool is web-based with a Java development environment and composed of a Digital Image and Communication in Medicine (DICOM) image viewer, a clinical information collector, and a database. The use of the tool with a sample case is demonstrated in this article. RESULTS: An online tool for the annotation of digital mammograms for teaching and research purposes has been developed. CONCLUSION: This annotation tool can be used to provide an annotated-case library on mammography education for residents and fellows.     

Factors affecting increasing radiation dose for mammography in North Carolina from 1997 through 2001: an analysis of Food and Drug Administration annual surveys

RATIONALE AND OBJECTIVES: To determine which factors affected the increase in average glandular dose recorded at the annual US Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 1997 to 2001. MATERIALS AND METHODS: Average glandular dose, HVL, kVp, ambient light, luminance, equipment age, processing speed, and system speed for every mammography unit at all facilities in the state were collected by state inspectors. A mixed-effect model was used to assess the average changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant increase in the average glandular dose in North Carolina in 1999, 2000, and 2001 when compared with the baseline year of 1997. Factors that were statistically significantly linked to this effect were changes in kVp, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has recently increased in North Carolina. This change is likely caused by changes in screen-film products and processing techniques.     

Improving efficacy of diabetes management using treatment algorithms in a mainly Hispanic population

OBJECTIVE: To compare clinical outcomes obtained using treatment algorithms versus standard "usual care" to treat patients with type 2 diabetes in a community setting. RESEARCH DESIGN AND METHODS: An observational group comparison was implemented in three community-based clinics in San Antonio, Texas: 1). a community clinic following treatment algorithms (CC-TA), 2). university clinic following treatment algorithms (UC-TA), and 3). a community clinic following standard "usual care" practices (CC-SC). Three hundred fifty-eight recently diagnosed type 2 diabetic patients (90% Mexican American, from low-income neighborhoods) who were consecutively identified at the three clinics were recruited. Following medical and laboratory evaluation, participants were started on treatment for hyperglycemia, hypertension, and dyslipidemia and followed for 12 months. RESULTS: Decrements in HbA(1c) at 12 months in the CC-TA and UC-TA were 3.1 and 3.3%, respectively, compared to 1.3% in the CC-SC (P < 0.0001). Corresponding decrements in fasting plasma glucose at 12 months were 94 and 99 mg/dl, respectively, versus 38 mg/dl in CC-SC (P < 0.0001). Reductions in total cholesterol, LDL cholesterol, and triglycerides at 12 months were greater in both algorithm-managed clinics compared to standard care-managed clinics (P < 0.0001). In algorithm-managed clinics, there were 30% more documented eye exams and 24% more documented foot exams than in standard care-managed patients. CONCLUSIONS: Adherence to the treatment algorithms improved metabolic outcomes in type 2 diabetic patients to a greater extent than standard care practices. These results have important clinical implications for the treatment of type 2 diabetic patients.