Computed tomography in patients with cerebrovascular disease: impact of a new technology on patient care

Diagnosing Suspected Stroke: A Cost-Effectiveness Analysis

Acute cerebrovascular disease (CBVD) has an annual incidence of 100–300 per 100,000 inhabitants in the industrialized countries (1,2). CBVD occurs mainly in the elderly. Acute mortality is around 15%. Disablement and decreased quality of life are common consequences. Institutionalized care will be needed after the acute phase for around one-third of the patients (3). Considering the volume of patients and the growing proportion of elderly persons in most countries, stroke poses a major problem for health care. An effective diagnostic work-up as the base for therapy to improve the situation is, therefore, a matter of great public concern, for humanitarian as well as economic reasons.

Immediate Computed Tomography Scanning of Acute Stroke Is Cost-Effective and Improves Quality of Life

BACKGROUND AND PURPOSE

Stroke is very common, but computed tomography (CT) scanning, an expensive and finite resource, is required to differentiate cerebral infarction, hemorrhage, and stroke mimics. We determined whether, and in what circumstances, CT is cost-effective in acute stroke.

METHODS

We developed a decision tree representing acute stroke care pathways populated with data from multiple sources. We determined the effect of diagnostic information from CT scanning on functional outcome, length of stay, costs, and quality of life during 5 years for 13 alternative CT strategies (varying proportions and types of patients and rapidity of scanning).

RESULTS

For 1000 patients aged 70 to 74 years, the policy "scan all strokes within 48 hours" cost 10,279,728 pounds sterling and achieved 1982.3 quality-adjusted life years (QALYs). The most cost-effective strategy was "scan all immediately" (9,993,676 pounds sterling and 1982.4 QALYs). The least cost-effective was "scan patients on anticoagulants and those in a life-threatening condition immediately and the rest within 14 days" (12,592,666 pounds sterling and 1931.8 QALYs). "Scan no patients" reduced QALYs (1904.2) and increased cost (10,544,000 pounds sterling).

CONCLUSIONS

Immediate CT scanning is the most cost-effective strategy. For the majority of acute stroke patients, increasing independent survival by correct early diagnosis, ensuring appropriate subsequent treatment and management decisions, reduced costs of stroke and increased QALYs.

Economic evaluation in stroke research : a systematic review

BACKGROUND AND PURPOSE

The purpose of this review is to provide insight into the quality of economic evaluation in the field of cerebrovascular diseases (CVD) on the basis of a systematic analysis.

METHODS

A literature search was performed using several sources. Trial-based full economic evaluation studies, were included in this review. The quality of the studies was independently assessed by 2 reviewers using a checklist.

RESULTS

Twenty-three articles were found to comply with our inclusion and exclusion criteria. Only a few studies mentioned the perspective of the study, and in these cases it was always the societal perspective. The majority of the studies were cost-minimization and cost-effectiveness analyses based on cohort studies. All studies included healthcare costs, and in some instances patient and family costs were considered. Costs were usually measured by tariffs. Clinical end points and mortality were used to measure effects. Cost and effect measurements were based on hospital records.

CONCLUSIONS

Only a few full economic evaluations have been undertaken in the domain of CVD. In most of the studies, the technical execution and methodology were limited.

Investigation of acute stroke: what is the most effective strategy?

Techniques of investigation of acute stroke syndromes have progressed rapidly in recent years, outpacing developments in effective stroke treatment. The clinician is thus faced with a variety of tests, each with different cost implications and each altering management to a greater or lesser extent. This review will concentrate on the basic tests which should be performed for all strokes (full blood count, ESR, biochemical screen, blood glucose, cholesterol, syphilis serology, chest X-ray and electrocardiogram). Additional tests may be required in selected cases: CT scan to diagnose 'non-stroke' lesions, to exclude cerebral haemorrhage if anti-haemostatic therapy is planned, and to detect strokes which may require emergency intervention (such as cerebellar stroke with hydrocephalus); echocardiography to detect cardiac sources of emboli; and in a few cases lumbar puncture and specialized haematological tests. Other tests, which are currently research tools, may be suitable for widespread use in the future including NMR, SPECT and PET scanning.

Correlation of clinical and computed tomographic findings in stroke patients

We evaluated the correlation between clinical features and computed tomographic findings in a prospective study of 1,191 consecutive patients with acute cerebrovascular disease seen during 1 year. In the 386 patients in whom symptoms and signs initially suggested a cerebrovascular disorder, computed tomography revealed a relevant lesion in 154 (hemorrhagic in 52 [33.8%], ischemic in 102 [66.2%]) and a significant nonstroke abnormality in 14 (3.1%). Among the remaining 805 patients with symptoms and signs suggesting some central nervous system disorder other than stroke, computed tomography revealed a cerebrovascular lesion in 38 (4.7%); 35 of these lesions were ischemic. The computed tomographic findings was compatible with the final clinical diagnosis in 192 (84.2%) of the 228 patients with lesions. In the entire sample of 1,191 patients, a cerebrovascular disorder would have been missed in 38 (3.2%) without computed tomography. On the other hand, computed tomography failed to visualize a cerebrovascular lesion in 40 patients in whom such a lesion was clinically obvious. Our results emphasize that both careful neurologic assessment and a policy of early computed tomography are of crucial importance in the diagnosis of stroke and for therapeutic considerations.

Long term effects of the introduction of noninvasive investigations in neuroradiology. Part 1: Overall trends

A 25 year retrospective survey of requests for imaging studies in a neurological hospital showed that the introduction of radionuclide scanning service had a relatively minor effect on the demand for other investigations. The introduction of computed tomography ten years later had a profound and continuing effect on not only the pattern and volume of requests for imaging, but also on inpatient discharges and outpatient attendances.

Applications of time-series analysis: a case study on the impact of computer tomography

Time-series techniques are applied to an analysis of the use of neurodiagnostic procedures in Athens, to evaluate the effect of the introduction of computer tomography. Results confirm the usefulness of such techniques, but illustrate the dependence of their successful application on the nature and quality of data.

The feasibility of economic evaluation of diagnostic procedures

This paper reviews the principles of cost-benefit and cost-effectiveness analysis as they are applied to diagnostic procedures. These medical procedures present particularly thorny problems to those who would subject them to economic evaluation. Five specific problem areas encountered in attempting to apply economic evaluation to diagnostic procedures are discussed in detail. They are: defining homogeneous patient groups for analysis; specifying the relevant diagnostic alternatives; measuring diagnostic accuracy; measuring diagnostic costs; and specifying the measured outcomes of the diagnostic process. The economic evaluation literature on two diagnostic procedures--the skull X-ray and computed tomographic (CT) scanning is reviewed within the context of a model of economic evaluation. Two studies were found to successfully apply the principles of economic evaluation to CT scanning; none were found for skull X-rays. The most common approaches to evaluating the usefulness of these procedures, and the limitations of these approaches, are summarized.

Stroke management of the elderly in Great Britain

Management of stroke in the elderly has been neglected in the past in Britain, but in recent years interest has taken an encouraging upturn. Obviously, the most satisfactory solution to the problem would be prevention, and epidemiologic research may prove important in this respect. Meanwhile, for those who are stricken, the best British physicians can offer is a careful and thoughtful approach to rehabilitation, carried out by a multidisciplinary team. The effects of rehabilitation need much more study; the main stumbling block to such research is the methodologic problem, to which more attention is now being paid. Each year in Britain, over 100,000 middle-aged and elderly people suffer a stroke, and many are disabled. Community services for these survivors need improvement so that care does not end with hospital discharge.

The lumbar puncture. Patterns of use in clinical practice

The records of 195 patients who had undergone lumbar puncture (LP) before or after the introduction of computerized axial tomography (CT) were reviewed. Twenty percent of the patients had potentially important spinal fluid abnormalities. The LP changed the diagnosis in 10% of the patients and changed therapy in 10% of the patients. It contributed to the patient's care in 32% of the patients prior to the introduction of the CT and in 48% of the patients after the introduction of the CT (p less than 0.05). Introduction of the CT was associated with a 35% decrease in the frequency of the LP (p less than 0.05). We found that fungal and AFB cultures did not appear to be indicated in most patients. We conclude that use of the LP has improved since the introduction of the CT. Further improvement is still possible, however.

Discrepancies between radionuclide and computed tomographic scans in detecting secondary neoplastic involvement of the brain

A radionuclide (RN) brain scan and a computed tomographic (CT) brain scan were performed on the same patient within one month on 207 occasions between February 1978 and October 1979 in order to investigate secondary neoplastic involvement of either metastatic or lymphomatous nature. The two scans were read independently of each other. There was a significant difference between the results of the two techniques in 26 of the 207 cases (13%). In 15 cases, the RN brain scan found clinically suspected secondary neoplastic involvement that was not detected by CT. In the other 11 cases, lesions detected by CT were not detected with the RN scan. Discrepancies were more frequent in patients with lymphoma than in patients with carcinoma.

The cost effectiveness of therapeutic and prophylactic leukocyte transfusion

We analyzed the cost effectiveness of leukocyte transfusion in preventing death from infection during intensive chemotherapy for acute leukemia. Effectiveness was estimated with an odds-ratio analysis based on published results of controlled studies of therapeutic and prophylactic leukocyte transfusion. Cost estimates were based on blood-bank charges throughout the country. Calculations of effectiveness suggest that leukocyte transfusion might prevent 50 to 75% of early deaths from infection. Therapeutic transfusion would add approximately 10.9% to the hospital bill of the average bill of the average leukemic patient and cost $17.7 million annually nationwide. Prophylactic transfusion would add 35.2% to the hospital bill and cost $57.8 million annually. Mean cost-effectiveness ratios were $14,982 per life-year for therapeutic transfusion and $35,020 to $50,029 per life-year for prophylactic transfusion. The cost per additional life-year achieved with prophylactic rather than therapeutic leukocyte transfusion was $85,291. These data suggest that leukocyte transfusion is an extremely expensive technologic procedure.

Computed tomography in patients presenting with lacunar syndromes

Of 312 stroke patients who had a CT scan, 37 had presented clinically with a lacunar syndrome. In 18 of the 37, lacunar sized infarcts were demonstrated on the scan, 13 had normal scans and in 6 large infarcts were found. Of these 6.5 and a pure motor hemiplegia and one a pure sensory stroke. Clinical evidence and angiography revealed a potential and treatable source of emboli in both the lacunar sized and the large infarcts. Two conclusions are drawn: a clinical lacunar syndrome may be associated with large infarct; demonstration of a lacunar infarct on CT scan does not exclude the need for angiography in appropriate cases to discover a possible source of emboli.

The diffusion of the computed tomography (CT) scanner in the United States

The rising cost of medical care in the United States is a problem generally familiar to all interested in health care policy. In recent years the contribution of technology to this rising cost has been debated. The computed tomography (CT) scanner has come to exemplify the problem of "technology run wild." The scanner was introduced into the United States in 1973 and has diffused rapidly into virtually every area of the country. However, despite the large number of scanners, they are mal-distributed by institutional setting and geographic location. A number of Federal policies have been developed to deal with medical technology. The case of the CT scanner illustrates the failure of these policies. The CT scanner was not well evaluated before it diffused into practice, and it appears that Federal reimbursement policy facilitated its spread. Federal policies designed to slow diffusion or to assure optimal placement or wise use of scanners have not had demonstrable effects. The case of the CT scanner suggests the need to alter Federal policies toward medical technologies.

Changes in neurological practice in South Australia after the introduction of computerized tomography

There has been no significant change in the age distribution of patients undergoing neuroradiological investigations after the introduction of computerized tomography (CT) in South Australia. The referral pattern has not changed, and adequate clinical neurological assessment was apparent both before and after the availability of CT, with the application of CT being selective rather than additive. Initial impression suggests some reduction in bed utilization after the introduction of CT.

Computer tomography as the primary radiologic procedure in acute subarachnoid hemorrhage

CT was performed in 149 patients with acute subarachnoid hemorrhage and clinical findings consistent with an aneurysm rupture, and was found informative in most cases when performed within one week after the hemorrhage. CT disclosed in 29 per cent of cases other causes for the hemorrhage than a ruptured aneurysm (intracerebral hemorrhage, tumor, trauma, infarct) and an extensive angiographic evaluation could be omitted. In those patients where the hemorrhage was caused by an aneurysm rupture, the distribution of extravasated blood in the subarachnoid space and the brain parenchyma usually indicated the aneurysm location--angiography could thus be restricted to the proper vessel. These capabilities of CT are sufficient to economically motivate its routine use as the primary investigation in cases with an acute subarachnoid hemorrhage.