Association of fasting glucose with subclinical cerebrovascular disease in older adults without Type 2 diabetes.

AIMS: To examine how fasting glucose and glucose tolerance are related to magnetic resonance imaging-assessed indicators of subclinical cerebrovascular disease and brain atrophy and their variation according to age, sex and education. METHODS: Participants in the present study were 172 healthy, community-dwelling older adults. An oral glucose tolerance test was administered and magnetic resonance imaging performed. Fasting, 2-h, and 2-h area-under-the-curve glucose levels, their associations with subclinical cerebrovascular disease and brain atrophy, and their respective interactions with age, sex and education were examined. RESULTS: A positive association between fasting glucose and subclinical cerebrovascular disease (but not brain atrophy) emerged; this association was more pronounced for participants with < 12 years of education; however, glucose tolerance was not related to subclinical cerebrovascular disease or brain atrophy. CONCLUSIONS: Findings revealed a potential link between fasting glucose levels and the presence of subclinical cerebrovascular disease indicators - white matter hyperintensities and silent brain infarction - in older adults without diabetes and with an education level below high school. Additional research is needed to confirm these associations and to determine the need for interventions aimed at closely monitoring and preventing elevated glucose levels in this population to reduce the prevalence of subclinical cerebrovascular disease.

False pulmonary artery catheter measurements due to the scimitar (hypogenetic lung) syndrome. Potential for iatrogenic pulmonary edema.

In an acute trauma patient with unrecognized scimitar syndrome, physiologic measurements used in patient management decisions were misleading due to the anatomic and physiologic anomalies of the syndrome. Pulmonary artery catheter measurements believed to reflect left atrial pressures were actually measuring central venous pressures because the catheter was terminating in the scimitar vein. These erroneous measurements led to overly aggressive fluid resuscitation and iatrogenic pulmonary edema. The pathologic features of scimitar syndrome are reviewed, and the mechanism for potential mismanagement of patient volume status created by aberrant pulmonary hemodynamics is discussed.

Hardcopy recording technologies for digitally formatted image data.

The hardcopy recording technologies of video cameras, slow-scan (digital spot) recorders, and laser film printers are presented and compared. Slow-scan (digital spot) recorders offer a few advantages when compared with multiformat video cameras. But only laser film printers provide the high-quality hardcopy recordings and speed required by newer digital imaging modalities.

Clinical experience in the use of photostimulable phosphor radiographic systems.

The experience with CR systems gained at the three institutions described in this report demonstrates numerous advantages over the conventional screen-film system. These include: (1) a reduction in the radiation exposure delivered to the patient (25% to 50%); (2) a decrease in the number of repeat examinations needed, especially in portable units where technical difficulties are common with screen-film examinations; this is attributable to the linear, wider dynamic range of CR systems compared with screen-film combinations; (3) the capability to archive electronically all images by means of a digital optical storage system; (4) automatic electronic setting of the laser scanner for the latitude and sensitivity on each image; (5) the digital images are available for transmission to all image display workstations on a local or wide-area network; and (6) the ability to adjust interactively the display parameters to best depict images and pathology as well as salvage technically suboptimal examinations. Several disadvantages of CR systems compared with conventional screen-film examinations have also been identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle size responses to strength training in young and older men and women.

OBJECTIVES: To examine the possible influences of age and gender on muscle volume responses to strength training (ST). DESIGN: Prospective intervention study. SETTING: University of Maryland Exercise Science and Wellness Research Laboratories. PARTICIPANTS: Eight young men (age 20-30 years), six young women (age 20-30 years), nine older men (age 65-75 years), and ten older women (age 65-75 years). INTERVENTION: A 6-month whole-body ST program that exercised all major muscle groups of the upper and lower body 3 days/week. MEASUREMENTS: Thigh and quadriceps muscle volumes and mid-thigh muscle cross-sectional area (CSA) were assessed by magnetic resonance imaging before and after the ST program. RESULTS: Thigh and quadriceps muscle volume increased significantly in all age and gender groups as a result of ST (P < .001), with no significant differences between the groups. Modest correlations were observed between both the change in quadriceps versus the change in total thigh muscle volume (r = 0.65; P < .001) and the change in thigh muscle volume versus the change in mid-thigh CSA (r = 0.76, P < .001). CONCLUSIONS: The results indicate that neither age nor gender affects muscle volume response to whole-body ST. Muscle volume, rather than muscle CSA, is recommended for studying muscle mass responses to ST.

Effects of age, gender, and myostatin genotype on the hypertrophic response to heavy resistance strength training.

BACKGROUND: Because of the scarcity of data available from direct comparisons of age and gender groups using the same relative training stimulus, it is unknown whether older individuals can increase their muscle mass as much as young individuals and whether women can increase as much as men in response to strength training (ST). In addition, little is known about whether the hypertrophic response to ST is affected by myostatin genotype, a candidate gene for muscle hypertrophy. METHODS: Eleven young men (25 +/- 3 years, range 21-29 years), 11 young women (26 +/- 2 years, range 23-28 years), 12 older men (69 +/- 3 years, range 65-75 years), and 11 older women (68 +/- 2 years, range 65-73 years) had bilateral quadriceps muscle volume measurements performed using magnetic resonance imaging (MRI) before and after ST and detraining. Training consisted of knee extension exercises of the dominant leg three times per week for 9 weeks. The contralateral limb was left untrained throughout the ST program. Following the unilateral training period, the subjects underwent 31 weeks of detraining during which no regular exercise was performed. Myostatin genotype was determined in a subgroup of 32 subjects, of which five female subjects were carriers of a myostatin gene variant. RESULTS: A significantly greater absolute increase in muscle volume was observed in men than in women (204 +/- 20 vs 101 +/- 13 cm3, p < .01), but there was no significant difference in muscle volume response to ST between young and older individuals. The gender effect remained after adjusting for baseline muscle volume. In addition, there was a significantly greater loss of absolute muscle volume after 31 weeks of detraining in men than in women (151 +/- 13 vs 88 +/- 7 cm3, p < .05), but no significant difference between young and older individuals. Myostatin genotype did not explain the hypertrophic response to ST when all 32 subjects were assessed. However, when only women were analyzed, those with the less common myostatin allele exhibited a 68% larger increase in muscle volume in response to ST (p = .056). CONCLUSIONS: Aging does not affect the muscle mass response to either ST or detraining, whereas gender does, as men increased their muscle volume about twice as much in response to ST as did women and experienced larger losses in response to detraining than women. Young men were the only group that maintained muscle volume adaptation after 31 weeks of detraining. Although myostatin genotype may not explain the observed gender difference in the hypertrophic response to ST, a role for myostatin genotype may be indicated in this regard for women, but future studies are needed with larger subject numbers in each genotype group to confirm this observation.

Muscle quality. II. Effects Of strength training in 65- to 75-yr-old men and women.

To determine the effects of strength training (ST) on muscle quality (MQ, strength/muscle volume of the trained muscle group), 12 healthy older men (69 +/- 3 yr, range 65-75 yr) and 11 healthy older women (68 +/- 3 yr, range 65-73 yr) were studied before and after a unilateral leg ST program. After a warm-up set, four sets of heavy-resistance knee extensor ST exercise were performed 3 days/wk for 9 wk on the Keiser K-300 leg extension machine. The men exhibited greater absolute increases in the knee extension one-repetition maximum (1-RM) strength test (75 +/- 2 and 94 +/- 3 kg before and after training, respectively) and in quadriceps muscle volume measured by magnetic resonance imaging (1,753 +/- 44 and 1, 955 +/- 43 cm3) than the women (42 +/- 2 and 55 +/- 3 kg for the 1-RM test and 1,125 +/- 53 vs. 1,261 +/- 65 cm3 for quadriceps muscle volume before and after training, respectively, in women; both P < 0.05). However, percent increases were similar for men and women in the 1-RM test (27 and 29% for men and women, respectively), muscle volume (12% for both), and MQ (14 and 16% for men and women, respectively). Significant increases in MQ were observed in both groups in the trained leg (both P < 0.05) and in the 1-RM test for the untrained leg (both P < 0.05), but no significant differences were observed between groups, suggesting neuromuscular adaptations in both gender groups. Thus, although older men appear to have a greater capacity for absolute strength and muscle mass gains than older women in response to ST, the relative contribution of neuromuscular and hypertrophic factors to the increase in strength appears to be similar between genders.

The role of transjugular intrahepatic portosystemic shunts in the management of patients with end-stage liver disease.

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) has been reported to successfully treat complications of portal hypertension; however, not all reports have been favorable. METHODS: Forty patients underwent 41 attempts to place a TIPS. All patients but 1 had a Wallstent placed. RESULTS: Thirty-nine procedures (95%) were successful. Thirty-one patients were treated for gastrointestinal bleeding, and 9 for refractory ascites. The average fall in portal pressure was 13.7 +/- 0.9 mm Hg. Major postprocedure complications included 4 deaths. Minor problems included liver capsular perforation, fever, self-limited bleeding, and a pseudoaneurysm. Follow-up evaluation revealed that by 5 months, 50% of the shunts developed a portal-venous-to-right-atrial pressure gradient requiring balloon dilatation or a new stent. The 1-year actuarial patient survival was 72%. Eighteen patients were candidates for orthotopic liver transplantation (OLT) and 5 have been transplanted. CONCLUSIONS: TIPS may be best used for stabilization, prior to OLT or as a temporizing measure prior to elective shunt surgery.

Is the role of transjugular intrahepatic portosystemic shunts limited in the management of patients with end-stage liver disease?

BACKGROUND: Transjugular intrahepatic portosystemic shunts (TIPS) are an established method for the treatment of the complications of portal hypertension. Recent reports have suggested that TIPS require frequent follow-up and may interfere with orthotopic liver transplantation (OLT). METHODS: Retrospective chart review was performed of ultrasound studies, angiographic studies, and complications of the first 100 patients treated consecutively with TIPS from February 1992 through October 1995. RESULTS: Ninety-seven patients had functional TIPS. Thirty-one percent of patients treated emergently survived, significantly less than the 96% survival of elective patients. Fifty percent of the shunts were found to require angioplasty by 5 months. Seventeen patients treated with OLT did well, without intraoperative bleeding problems, and are alive. CONCLUSIONS: The TIPS method treats successfully the complications of portal hypertension but requires careful follow-up. The technique may be used prior to OLT. For non-OLT candidates, the cost effectiveness of TIPS versus surgical shunting remains in question.

Vena caval occlusion after bird's nest filter placement.

BACKGROUND: Inferior vena caval thrombosis as a result of intracaval barrier devices occurs in 6.5% of patients with Greenfield filters. The incidence is less well defined in patients in whom bird's nest filters have been placed. We reviewed our experience with bird's nest filters to determine the incidence of filter-induced caval thrombosis. METHODS: The records of 140 patients with bird's nest filters were reviewed, living patients were interviewed, and the inferior vena cava examined in 37 patients by duplex scanning. RESULTS: Ninety-three patients were available for evaluation. Five of these patients were found to have caval thrombosis by duplex scanning and 2 had clinical symptoms and signs compatible with caval thrombosis. The majority of these patients were on anticoagulants at the time of filter thrombosis. CONCLUSION: The incidence of filter-induced vena caval thrombosis in patients with bird's nest filters (7%) is comparable with that of Greenfield filters. Because of the catastrophic manifestations of this complication and the increasing application of vena caval filters, the role of these filters in the treatment of thrombotic disease needs further critical evaluation.

Iodixanol and ioxaglate in adult aortography and peripheral arteriography: a phase III clinical trial.

RATIONALE AND OBJECTIVES: This study compared the safety and efficacy of iodixanol with those of ioxaglate in adult patients undergoing aortography or peripheral arteriography. METHODS: Forty-six patients were enrolled in this controlled, randomized, double-blind, two-center study. The patients were monitored for adverse events, injection-related discomfort, and trends in laboratory data or vital signs. Diagnostic efficacy was assessed by the quality of contrast enhancement. RESULTS: All procedures were diagnostic, with no significant difference in quality of visualization (p = .205). No significant difference was seen in the number of patients experiencing mild or moderate adverse effects (p = .106). Patients receiving ioxaglate reported a significantly greater incidence of injection-related pain (p = .025). CONCLUSION: The results of this study support the conclusion that iodixanol at 320 mg I/kg is safe and effective for adult aortography and peripheral arteriography and causes significantly less injection-related pain than ioxaglate.

Comparison of iodixanol and ioxaglate for adult aortography and renal/visceral angiography: a phase III clinical trial.

RATIONALE AND OBJECTIVES: We investigated whether iodixanol offers improved safety or tolerance compared with ioxaglate and evaluated whether iodixanol-enhanced radiographs are diagnostically comparable or superior to those produced with ioxaglate. Iodixanol is a new isosmotic hexa-iodinated nonionic contrast agent being evaluated for intravascular use. METHODS: Fifty-four adult patients undergoing renal or visceral angiography, aortography, or both were enrolled in a prospective, randomized, double-blind, two-center study in which iodixanol and ioxaglate were compared. Subjects were monitored for adverse events, injection-associated discomfort, and changes in laboratory parameters and vital signs. Efficacy was measured by the overall quality of angiographic enhancement. RESULTS: No serious adverse events occurred during this trial. Mild-to-moderate adverse events were more common in patients receiving ioxaglate (p = .041). Injection-associated pain was reported by three patients receiving ioxaglate and none receiving iodixanol (p = .093). Clinical laboratory and vital-sign data showed no differences between groups, and there was no difference in the overall quality of angiographic visualization (p = .711). CONCLUSION: Iodixanol resulted in improved safety and patient tolerability while providing images of equivalent diagnostic efficacy compared with ioxaglate.

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.

Internal carotid artery sacrifice.

Sacrifice of the ICA can be used to treat a variety of conditions. Whenever possible, temporary occlusion of the carotid artery should be performed before the actual sacrifice to evaluate for tolerance to the occlusion. In many cases, endovascular occlusion of the carotid artery is preferable to surgical occlusion.

Economic and clinical impact of filmless operation in a multifacility environment.

The transition from conventional film-based to filmless operation at the Baltimore Veterans Affairs (VA) Medical Center has resulted in a large number of clinical and economic benefits. The integration of the Department of VA hospitals in Maryland into the VA Maryland Health Care System has resulted in the opportunity to establish a "virtual" radiology and nuclear medicine department. This integrated department is based on a wide area network in which outlying medical centers use a central hospital information system/radiology information system (HIS/RIS) and a central commercial picture archiving and communication system (PACS), as well as a VA-developed image management and communication system. The creation of this virtual radiology/nuclear medicine department has resulted in additional savings and improvements in clinical care. The benefits of the PACS are made possible, to a large extent, by the high level of integration of the PACS and medical modalities with the hospital information and transcription systems. Our experience suggests that it is absolutely essential to integrate the PACS into the patient's electronic medical record to maximize efficiency and clinical effectiveness of the system.

Challenges associated with the incorporation of digital radiography into a picture archival and communication system.

Digital radiography (DR) has recently emerged as an attractive alternative to computed radiography (CR) for the acquisition of general radiographic studies in a digital environment. It offers the possibility of improved spatial and contrast resolution, decreased radiation dose due to improved efficiency of detection of x-ray photons, and perhaps most importantly, holds out the promise of increased technologist productivity. To achieve maximum efficiency, DR must be completely integrated into existing information systems, including the hospital and radiology information systems (HIS/RIS) and, when present, the picture archival and communication system (PACS). The early experience with the integration of DR at the Baltimore Veterans Affairs Medical Center (VAMC) has identified several challenges that exist to the successful integration of DR. DR has only recently been defined as a separate Digital Imaging and Communications in Medicine (DICOM) modality and images obtained will, at first, be listed under the category of CR. Matrix sizes with some DR products on the market exceed the current size limitations of some PACS. The patient throughput may be substantially greater with DR than with CR, and this in combination with the larger size of image files may result in greater demands for network and computer performance in the process of communication with the HIS/RIS and PACS. Additionally, in a hybrid department using both CR and DR, new rules must be defined for prefetching and display of general radiographic studies to permit these examinations to be retrieved and compared together. Advanced features that are planned for DR systems, such as dual-energy subtraction, tomosynthesis, and temporal subtraction, will likely require additional workstation tools beyond those currently available for CR.

Recommendations for image prefetch or film digitization strategy based on an analysis of an historic radiology image database.

Picture archiving and communications systems (PACS) utilize short- and long-term storage to provide both rapid retrieval and large storage capacity. Owing to the practical limitations imposed on the size of the much faster short-term storage, it is important to use an effective algorithm in the retrieval of comparison images from long to short-term storage. A strategy must be used to maximize the likelihood that the relevant historic images have been previously retrieved into short-term memory. Data were collected with a database consisting of 754 consecutive examinations and 7,723 associated historic studies. The most frequent number of previous examinations was zero (11% of patients). In 45% of cases, no previous matching examinations had been performed. Two basic strategies of image retrieval were evaluated. The first algorithm retrieved the last n studies in chronological order. The second strategy tested was retrieval based on a defined interval of time. This strategy was found to be less efficient. By using the former strategy, a 91% success rate (defined as successful retrieval of the previous matching exam) was achieved with retrieval of only 30% of the prior exams. The second approach required retrieval of 70% of the prior exams to achieve a 90% success rate for the previous matching exam. However, the data from this latter strategy suggest that examinations are often ordered in clusters. Thus, there was found to be a 72% likelihood that a previous matching exam, if present, would available on a PACS after only 1 week of operation, and an 80% chance after only 1 month of operation. The data therefore suggest that digitization of film in a new PACS environment might not be necessary owing to the relatively short period of time required to populate the database with historical studies.

Integrating the Healthcare Enterprise: a primer. Part 1. Introduction.

Does the subject of this series of articles intrigue you but you're not sure if the topics covered really apply to you and your practice? Before you read another word, go to the end of this introduction and seriously try to answer the questions posed there. If you answer "yes" to questions 1, 4, 5, 6, and 7, you need to read these articles.