Magnetic resonance imaging. Diffusion of technology in an ambulatory setting

The effect of helical computed tomography on diagnostic and treatment strategies in patients with suspected pulmonary embolism

BACKGROUND

Helical computed tomography (CT) has been proposed as a first-line test for the diagnosis of pulmonary embolism. How the test affects the diagnostic evaluation of patients with suspected pulmonary embolism is unknown.

METHODS

We examined a cohort of 360 patients evaluated for pulmonary embolism at a teaching hospital in the 4 years following the introduction of the helical CT scan. We collected patient demographic and clinical data to calculate the pretest likelihood of pulmonary embolism; we then read the test results and determined rates of further testing and treatment for pulmonary embolism.

RESULTS

After the helical CT scan became available, the number of patients referred for pulmonary embolism testing increased markedly from 170 to 624 total evaluations during 1997 to 2000 (P <0.01). This rise was due to increased use of the helical CT scan (9% to 83% of evaluations, P <0.01) as the use of ventilation-perfusion scanning (79% to 17%, P = 0.03) and pulmonary angiography (12% to <1%, P <0.01) fell. There was no change in the pre-test likelihood of disease over time, but the percentage of scans that were positive for pulmonary embolism rose (14% to 32%, P =0.02). Clinicians treated all patients who had a positive CT scan, but became less likely over time to order further testing for patients who had a negative scan (30% to 12%, P = 0.02).

CONCLUSION

At this academic medical center, introduction of the helical CT scan had a profound effect on the evaluation of pulmonary embolism, resulting in more frequent use of the CT scan, and more frequent diagnosis and treatment of pulmonary embolism, despite no change in the pretest probability of disease. Future studies should confirm our findings and determine whether increased detection of pulmonary emboli results in improved outcomes.

Using an Improvement Model to Reduce Adverse Drug Events in VA Facilities

BACKGROUND

Adverse drug events cause significant morbidity and mortality in health care. Many adverse drug events are due to medication errors and are preventable. In 1999 and 2000 the Patient Safety Center of Inquiry collaborated with the Institute for Healthcare Improvement (IHI) to implement a quality improvement (QI) project designed to reduce medication errors within the Veterans Administration system.

METHODS

During a 6- to 9-month period, interdisciplinary teams that want to achieve much higher levels of performance work on a common aim, under the guidance of faculty, and come together for three 2-day educational and planning sessions. Between these sessions, teams implement some of the suggested changes, measure the results of those changes, and report back to the larger group.

RESULTS

During the formal project, teams collected allergy information on more than 20,000 veterans and averted 1,833 medication errors that had the potential to cause adverse events. At 6-month follow-up, the majority of teams remained intact, continued to collect data, and maintained their gains, approximately doubling the results obtained during the formal project. Half of the teams expanded their efforts to other settings, and one-third of the teams expanded beyond their original topics. Returns on investment in the QI effort were substantial.

CONCLUSIONS

The results suggest that gains made in organized QI efforts can be maintained for 6 months without additional external support or coaching if team structure and leadership support remain intact. Facilitators of QI efforts should focus on teams that are having difficulty learning new techniques. Finally, this effort appeared to generate cost savings.

The cost-effectiveness of magnetic resonance imaging for patients with equivocal neurological symptoms

OBJECTIVE

To determine the incremental cost-effectiveness of magnetic resonance imaging (MRI) and computed tomography (CT) in young adults presenting with equivocal neurological signs and symptoms.

DESIGNS AND METHODS

A decision analysis of long-term survival using accuracy data from a diagnostic technology assessment of MRI and CT in patients with suspected multiple sclerosis, information from the medical literature, and clinical assumptions.

MAIN RESULTS

In the baseline analysis, at 30% likelihood of an underlying neurologic disease, MRI use has an incremental cost of $101,670 for each additional quality-adjusted life-year saved compared with $20,290 for CT use. As the probability of disease increases, further MRI use becomes a cost-effective alternative costing $30,000 for each quality-adjusted life-year saved. If a negative MRI result provides reassurance, the incremental costs of immediate MRI use decreases and falls below $25,000 for each quality-adjusted life-year saved no matter the likelihood of disease.

CONCLUSIONS

For most individuals with neurological symptoms or signs, CT imaging is cost-effective while MR imaging is not. The cost-effectiveness of MRI use, however, improves as the likelihood of an underlying neurological disease increases. For selected patients who highly value diagnostic information, MRI is a reasonable and cost-effective use of medical resources when even the likelihood of disease is quite low (5%).

Health care technology as a policy issue

Health care technology has become an increasingly visible issue in many countries, primarily because of the rising costs of health care. In addition, many questions concerning quality of care are being raised. Health care technology assessment has been seen as an aid in addressing questions concerning technology, including benefits and costs. A number of industrialized countries have developed active programs of health care technology assessment during the past two decades. Eight countries at similar levels of socio-economic and health development--Australia, Canada, France, Germany, the Netherlands, Sweden, the United Kingdom and the United States--have been examined to gain insights into how they manage health care technology and what place technology assessment has in such management. In addition to seeking general information, specific cases--treatment for coronary artery disease, medical imaging, laparoscopic surgery, treatment of end-stage renal disease, neonatal intensive care, and breast cancer screening--were examined in each country.

Physicians' influence on the decision to acquire magnetic resonance imagers in acute care hospitals

The influences of four principal types of decision makers on the acquisition of magnetic resonance imagers were measured in hospitals in Southern California, Oregon, and Washington. We propose that of the decision makers assessed, physicians had the most influence on the acquisition of magnetic resonance imagers.

Health care cost containment: rationing medical technology

Effective and efficient delivery of health care is one of the critical issues facing the nation today. Currently, nearly 13% of the nation's GDP in spent on Health Care. Perhaps one-half of the increase in health care costs have been linked to the acquisition of new medical technology. This paper examines some of the issues relating to the acquisition and dissemination of the use of medical technology by acute care and outpatient facilities and discusses the rationing of medical technology. The paper concludes by identifying some of the approaches to controlling health care costs through the rationing of technology that have been presented in the literature and outlines the evolving new paradigm that is being advanced to address the issues of cost containment and access to health care.

The influence of health technology assessment on the diffusion of MRI in Australia

A major assessment of magnetic resonance imaging (MRI) in Australia influenced the early use of this technology and informed policy decisions on future MRI services. However, the impact of the assessment, and of government policy, on the subsequent diffusion of MRI has been more modest, reflecting the limitations of the evaluation process in a complex health care system.