Frank J. Hooper

Elevated urine uranium excretion by soldiers with retained uranium shrapnel.

The use of depleted uranium in munitions has given rise to a new exposure route for this chemically and radioactively hazardous metal. A cohort of U.S. soldiers wounded while on or in vehicles struck by depleted uranium penetrators during the Persian Gulf War was identified. Thirty-three members of this cohort were clinically evaluated, with particular attention to renal abnormalities, approximately 3 y after their injury. The presence of retained shrapnel was identified by x ray, and urine uranium concentrations were measured on two occasions. The absorption of uranium from embedded shrapnel was strongly suggested by measurements of urine uranium excretion at two time intervals: one in 1993/1994 and one in 1995. Mean urine uranium excretion was significantly higher in soldiers with retained shrapnel compared to those without shrapnel at both time points (4.47 vs. 0.03 microg g(-1) creatinine in 1993/1994 and 6.40 vs. 0.01 microg g(-1) creatinine in 1995, respectively). Urine uranium concentrations measured in 1995 were consistent with those measured in 1994/1993, with a correlation coefficient of 0.9. Spot urine measurements of uranium excretion were also well correlated with 24-h urine collections (r = 0.95), indicating that spot urine samples can be reliably used to monitor depleted uranium excretion in the surveillance program for this cohort of soldiers. The presence of uranium in the urine can be used to determine the rate at which embedded depleted uranium fragments are releasing biologically active uranium ions. No evidence of a relationship between urine uranium excretion and renal function could be demonstrated. Evaluation of this cohort continues.

The efficacy and safety of a continuous albuterol protocol for the treatment of acute adult asthma attacks

We performed a prospective study over a 6-month period to test the efficacy and safety of a continuous nebulized albuterol protocol for the treatment of acute adult asthma attacks. All patients 18 years or older presenting to the emergency department with acute asthma attacks were begun by the triage nurse on the protocol of three continuous albuterol (2.5 mg) nebulizer treatments. Pretreatment and posttreatment peak flow, respiratory rate, pulse, and blood pressure were documented and patients gave a pretreatment and posttreatment rating of the clinical severity of their attack using a (1 to 10) visual analog scale. In addition, all adverse effects were noted. Seventy-six patients were entered in the study. The average age was 44 years (range, 20 to 82 years). Pretreatment and posttreatment peak flow, respiratory rate, pulse, blood pressure, and clinical severity were compared using the paired t test. Patients showed statistically significant increases in peak flow (128 to 292; P < .0001) and statistically significant decreases in respiratory rate (27 to 20; P < .0001); pulse, 103 to 94 (P < .0001); clinical severity, 7.8/10 to 1.8/10 (P < .0001); and blood pressure, 141/82 to 132/77 (P < .001). Adverse effects were minimal. Two patients (2.6%) felt flushed, three patients (4%) felt jittery, and one patient (1.3%) had a sensation of palpitations. We conclude that a continuous nebulized albuterol protocol is both extremely efficacious and safe for the treatment of acute adult asthma attacks.

Picture archiving and communication system training for physicians: Lessons learned at the Baltimore VA Medical Center

Physicians practicing at the “filmless” Baltimore VA Medical Center need to be proficient in the use of the picture archiving and communication system (PACS) to be able to view radiologic images and accompanying reports. PACS training is necessary to assure optimal patient care and to satisfy potential medicolegal requirements. Providing such training is the responsibility of both the Imaging Department and the hospital. Training in the use of the PACS at the Baltimore VA is conducted by an on-site application specialist. Data were collected from interviews with the trainer, training log sheets, and physician surveys. Although 100% of radiologists received formal training, only 22% of nonradiologists were formally trained; 32% of these physicians identified themselves as having been trained by their peers and 41% stated they were self-trained. We identified two goals of a PACS training program. The first is to teach physicians how to retrieve images and reports from current as well as prior studies and display them on a computer workstation. Secondly, the training should include instruction on the use of the various workstation tools to enhance image interpretation. Imaging requirements and usage by different physician groups vary, and PACS training should be tailored accordingly. Difficulties in the scheduling of training sessions during working hours and the widespread use of a “generic” log-on identification have contributed to the low (22%) compliance of nonradiologists with the formal training program. Although we believe that one-on-one training is most effective and can be best tailored to the needs and computer expertise of an individual particular physician, computer based training (both on and off-line) may provide an acceptable, and in some cases, a preferred alternative.

Picture archiving and communication systems and vascular surgery: clinical impressions and suggestions for improvement.

The purpose of this study was to determine the acceptance and clinical utility of a large scale picture archiving and communication system (PACS) for vascular surgery. Questionnaires and one-on-one interviews were conducted with physicians and nurses in the department of vascular surgery at the Baltimore VA Medical Center where PACS has been in routine, hospital-wide use for more than 21/2 years. The perceptions of the clinical staff were assessed to determine the efficacy of PACS in comparison to the conventional film based alternative for the practice of vascular surgery and suggestions for improvements were solicited. There was consensus among the vascular surgery staff members that the use of PACS enhanced their clinical practices, both in and out of the operating room (OR). Vascular surgeons heavily rely on image display in the OR as a “road map” to help determine their operative approach and to guide their surgery. PACS offers unique intraoperative imaging capabilities including rapid image retrieval and improved archival, cine review, the ability to modify image contrast, and the ability to obtain direct quantitative measurements of the degree of vascular stenosis. The increased accessibility and availability of images throughout the hospital enables improvements in time management and in patient care.

Cranial computed tomography in the emergency department evaluation of HIV-infected patients with neurologic complaints

STUDY OBJECTIVE To demonstrate the usefulness of cranial computed tomography (CT) in the emergency department evaluation of HIV-infected patients and patients with risk factors for HIV infection who present with neurologic complaints. DESIGN Retrospective review of imaging reports and medical records of patients who visited the ED from March 1991 through March 1992. SETTING Urban university ED. PARTICIPANTS Patients with HIV infection or risk factors for infection who underwent emergency cranial CT after presenting to the ED with headache, altered mental status, focal deficits, or other neurologic signs or symptoms. RESULTS One hundred forty-six patients visited the ED 169 times. Of the 169 cranial CTs obtained, 85 (50%) were normal, 49 (29%) showed atrophy only, and 35 (21%) demonstrated focal lesions, with mass effect noted in ten (6%). Enhancing lesions were present in 13 scans. In 21 (12%) cases, CT revealed either an indication for admission, a contraindication to lumbar puncture, or both. In 25 instances, patients with lesions had nonfocal presentations and no papilledema. Two presentations--focal deficit and altered mental status--were each statistically significantly associated with lesions on CT. In seven patients with multiple ED visits, repeat CT showed new findings. Among patients who had risk factors but were of unknown HIV status, there was the same proportion of abnormal scans as in known HIV-infected patients. CONCLUSION CT detected clinically significant neuropathology among our study patients. Because lesions and mass effect were associated with nonfocal as well as focal presentations, CT is indicated in every neurologically symptomatic patient with HIV infection or risk factors for infection. Because HIV-related diseases can progress rapidly, repeat CT is recommended even in patients with recent scans.

Variation of monitor luminance on radiologist productivity in the interpretation of skeletal radiographs using a picture archiving and communication system

T HE cathode ray tube (CRT) display used in picture archiving and communication system (PACS) workstations have been shown to have lower spatial resolution and luminance compared with conventional film-screen radiographs displayed on an illuminator. Laboratory observer studies indicate display brightness to be an important parameter in the interpretation of radiological images. This study was undertaken to evaluate the effects of varying monitor luminance on radiologist productivity and accuracy in the interpretation of skeletal radiographs with the hope of identifying the ideal monitor luminance for everyday practice. One hundred randomly selected skeletal radiographs were evatuated prospectively by three board certified radiologists with extensive PACS experience. Each examination was reviewed independently on a four-monitor, high-resolution (2048 • 1536 pixels) workstation at three different levels of monitor brightness (40, 65, and 90 footlamberts). Ambient room light was maintained at a constant level throughout the study. Interpretation

Effect of monitor image quality on the soft-copy interpretation of chest CR images

Four radiologists independently reviewed eighty individual thoracic computed radiography images. These consisted of 41 normal radiographs and 39 abnormal radiographs. Images were reviewed using 2,048 by 1,536 pixel monitors which varied widely in image quality as documented using a SMPTE pattern. Overall sensitivity for pathology ranged from .94 to .97 for the radiologists and varied minimally (0.95 to 1.0) for the four monitor quality levels tested while specificity varied to a much greater extent for the radiologists (0.68 to 0.93) and for the various monitors (0.76 to 0.93). The control (good quality) monitor demonstrated substantially higher specificity than the other three monitors (which varied from very poor to fair) but there were no significant differences among the non-control monitors despite their wide variance with regard to image quality. There was no significant difference in sensitivity for the monitors (including the control). Additionally no significant differences were found in the level of diagnostic confidence by the radiologists for the four monitors. These findings suggest that the actual effect of monitor quality degradation on clinical accuracy and confidence is complex and correlates poorly with traditional quality assurance metrics performed for these systems. Additional investigation into the monitor characteristics which most affect clinical confidence and performance is warranted.

Effect of screen monitor number on radiologist productivity in the interpretation of portable chest radiographs using a picture archiving and communication system.

p [CTURE archiving and communication systetas (PACS) offer unique improvements in operational efficiency when compared with filmbased imaging by providing economical storage, rapid image retrieval, increased image accessibility, elimination of lost images, and reduction in film retakes. Radiologist produ.ctivity is dependent upon workstations facilitating fast and accurate interpretations. This study evaluates the effect of workstation monitor number on radiologist efficiency and accuracy in the interpretation of portable chest radiographs. Time-motion studies were performed evaluating radiologist interpretation of portable chest radiographs using one-, two-, and four-monitor displays (2048 x 1536 pixels). Three board certified radiologists with extensive PACS experience prospectively evaluated 100 portable chest radiographs that were randomly assigned to one, two, or four monitors. In addition to evaluating the time rcquired for image interpretation, accuracy was assessed comparing individual radiologist interpretation with those of an expert review panel. In all cases, comparison studies and reports were available at the time of image review. As the number of monitors increased, overall time requirements in image display and interpretation progressively decreased. This accentuation in time savings was of greatest magnitude when the number of comparison studies increased and was independent of the radiologist. The overall accuracy of interpretation was not affected significantly by differences in monitor number, with consistent reporting accuracy for all radiologists. Radiologists subjectively reported fatigue to be inversely proportional to monitor number. Use of a four-monitor workstation produces significant time savings when compared with oneand two-monitor workstations in the interpretation of portable chest radiographs. Although overall interpretation accuracy is not affected significantly by monitor number, there is a reported reduction in radiologist fatigue as the monitor number increases, which leads to further enhancements in radiologist productivity.

Efficacy and safety of a rapid-sequence metaproterenol protocol in the treatment of acute adult asthma

A 6-month prospective study was performed to examine the efficacy and safety of a rapid-sequence nebulized metaproterenol regimen for the treatment of acute asthma in adults. Patients 18 years of age or older who were not pregnant and who had not received beta 2-agonist therapy were identified and started on a rapid-sequence metaproterenol regimen (15 mg) by the triage nurse. Pretreatment and posttreatment peak flow, respiratory rate, pulse rate, and blood pressure were documented. Patients also gave a pretreatment and posttreatment rating of the clinical severity of their attack using a 1-to-10 visual analogue scale. Fifty patients were entered into the study, with an average age of 38 years (range, 19 to 87 years). Data were analyzed using the Wilcoxon matched-pairs signed rank test. Patients showed statistically significant increases in peak flow (193 to 328 L/min, P < .00001) and systolic blood pressure (136 to 143 mm Hg, P < .0054). Statistically significant decreases were shown for respiratory rate (25 to 22 beats/min, P < .0001) and clinical severity (6.2 to 3.2, P < .00001). Thirty-three patients (71%) who completed the protocol experienced an increase in pulse rate. Ten (21%) had a pulse rate increase of more than 30 beats/min. Two (4.2%) had pulse rate increases of more than 40 beats/min. Four patients were removed after one or two nebulizers because of severe side effects. One patients pulse rate increased to more than 200 beats/min. Although effective in reversing bronchospasm, the side effects of metaproterenol when used in rapid sequence are of major concern.