Can academic radiology departments become more efficient and cost less?

PURPOSE

To determine how successful two large academic radiology departments have been in responding to market-driven pressures to reduce costs and improve productivity by downsizing their technical and support staffs while maintaining or increasing volume.

MATERIALS AND METHODS

A longitudinal study was performed in which benchmarking techniques were used to assess the changes in cost and productivity of the two departments for 5 years (fiscal years 1992-1996). Cost per relative value unit and relative value units per full-time equivalent employee were tracked.

RESULTS

Substantial cost reduction and productivity enhancement were realized as linear improvements in two key metrics, namely, cost per relative value unit (decline of 19.0% [decline of $7.60 on a base year cost of $40.00] to 28.8% [$12.18 of $42.21]; P < or = .001) and relative value unit per full-time equivalent employee (increase of 46.0% [increase of 759.55 units over a base year productivity of 1,651.45 units] to 55.8% [968.28 of 1,733.97 units]; P < .001), during the 5 years of study.

CONCLUSION

Academic radiology departments have proved that they can "do more with less" over a sustained period.

Dual-isotope single-photon emission computerized tomography scanning in patients with glioblastoma multiforme: association with patient survival and histopathological characteristics of tumor after high-dose radiotherapy

OBJECT

The study was conducted to determine the association between dual-isotope single-photon emission computerized tomography (SPECT) scanning and histopathological findings of tumor recurrence and survival in patients treated with high-dose radiotherapy for glioblastoma multiforme.

METHODS

Studies in which SPECT with 201Tl and 99mTc-hexamethypropyleneamine oxime (HMPAO) were used were performed 1 day before reoperation in 47 patients with glioblastoma multiforme who had previously been treated by surgery and high-dose radiotherapy. Maximum uptake of 201Tl in the lesion was expressed as a ratio to that in the contralateral scalp, and uptake of 99mTc-HMPAO was expressed as a ratio to that in the cerebellar cortex. Patients were stratified into groups based on the maximum radioisotope uptake values in their tumor beds. The significance of differences in patient gender, histological characteristics of tissue at reoperation, and SPECT uptake group with respect to 1-year survival was elucidated by using the chi-square statistic. Comparisons of patient ages and time to tumor recurrence as functions of 1-year survival were made using the t-test. Survival data at 1 year were presented according to the Kaplan-Meier method, and the significance of potential differences was evaluated using the log-rank method. The effects of different variables (tumor type, time to recurrence, and SPECT grouping) on long-term survival were evaluated using Cox proportional models that controlled for age and gender. All patients in Group I (201Tl ratio < 2 and 99mTc-HMPAO ratio < 0.5) showed radiation changes in their biopsy specimens: they had an 83.3% 1-year survival rate. Group II patients (201Tl ratio < 2 and 99mTc-HMPAO ratio of > or = 0.5 or 201Tl ratio between 2 and 3.5 regardless of 99mTc-HMPAO ratio) had predominantly infiltrating tumor (66.6%); they had a 29.2% 1-year survival rate. Almost all of the patients in Group III (201Tl ratio > 3.5 and 99mTc-HMPAO ratio > or = 0.5) had solid tumor (88.2%) and they had a 6.7% 1-year survival rate. Histological data were associated with 1-year survival (p < 0.01): however, SPECT grouping was more closely associated with 1-year survival (p < 0.001) and was the only variable significantly associated with long-term survival (p < 0.005).

CONCLUSIONS

Dual-isotope SPECT data correlate with histopathological findings made at reoperation and with survival in patients with malignant gliomas after surgical and high-dose radiation therapy.

Preclinical prediction of Alzheimer's disease using SPECT

BACKGROUND

Regional cerebral perfusion measured by single photon emission computed tomography (SPECT) was examined as a preclinical predictor of the development of Alzheimer's disease (AD).

METHODS

Singular value decomposition was used to produce 20 SPECT factors (known as vectors) (n=152). Vector scores were then computed for four groups (n=136), differing in cognitive status: Group 1--normal controls at both baseline and follow-up; Group 2--subjects with "questionable" AD at both baseline and follow-up; Group 3--subjects with questionable AD at baseline who converted to AD on follow-up (Converters); Group 4--subjects with AD at baseline. All SPECT data in the analyses were gathered at baseline.

RESULTS

The four groups could be distinguished on the basis of their baseline SPECT data (p < or = 0.00005; hit rate=83%). Regional decreases in perfusion were most prominent among Converters in the hippocampal-amygdaloid complex, the posterior cingulate, the anterior thalamus, and the anterior cingulate. Inclusion of apolipoprotein E status did not significantly improve the discrimination.

CONCLUSIONS

SPECT data gathered and analyzed in this manner may be useful as one aspect of the preclinical prediction of AD. Three of the four brain regions important for discriminating Converters from normal controls involve a distributed brain network pertaining to memory, suggesting that this network may be selectively affected in the earliest stages of AD.

Use of singular value decomposition to characterize age and gender differences in SPECT cerebral perfusion

The main objective of this study was to characterize changes in brain perfusion associated with normal aging and gender.

METHODS

Perfusion SPECT images using 99mTc-hexamethyl propyleneamine oxime (HMPAO) were obtained from 152 healthy subjects (67 men, 85 women) aged 50-92 yr. An automated method was developed to objectively assess image data from a large number of brain regions. Image data were reduced with singular value decomposition (SVD), which produced 20 eigenvectors capturing 97.05% of the total information content of 4320 regions from each subject. Subjects were scored individually on each vector.

RESULTS

Multivariate analyses demonstrated that there were no significant differences in whole-brain HMPAO uptake with age, but age-related regional declines were seen in lateral ventricular regions. Women had higher HMPAO uptake than men in estimates of global perfusion and regional perfusion in the midcingulate/corpus callosum, inferior temporal and inferior parietal areas.

CONCLUSION

These discriminations demonstrate that singular value deomposition of SPECT data may be used to assess differences in perfusion patterns between groups of subjects. They replicate several previous findings, both with respect to age-related changes in perfusion and with respect to gender differences. In addition, they identify a previously unreported gender difference in biparietal regions.

Web-based digital radiology teaching file: facilitating case input at time of interpretation

OBJECTIVE

Our goal was to develop a software system that allows easy and rapid input of digital radiology images and text reports, at the time of interpretation, into an easily searchable electronic teaching file database using the Internet and the World-Wide Web protocols, servers, and browsers.

CONCLUSION

Using the Internet, the World-Wide Web, and our software system, we can rapidly input digital radiology images and associated text reports into an easily searchable database accessed by privileged users. This inexpensive and simple method for building a digital teaching file database allows cross-platform access for users who have a Web browser.

Percutaneous abdominal biopsy: cost-identification analysis

PURPOSE

To determine the difference in cost to providers of percutaneous abdominal biopsy as the first strategy versus surgical biopsy.

MATERIALS AND METHODS

Cost of tissue diagnosis determination with percutaneous biopsy as the first strategy in 439 patients with an abdominal mass was estimated. Costs included direct hospital costs and professional costs of initial and repeat biopsy, follow-up imaging and clinic visits, surgical biopsy (when needed), and treatment of complications. The sum of these costs was compared with the estimated cost had the same patients undergone surgical biopsy instead, with no complications or need for follow-up or repeat biopsy.

RESULTS

The total estimated cost of percutaneous biopsy as the first strategy ($543,245) was less than the cost had surgical biopsy been used alone ($1,919,867). The average per patient direct hospital cost of percutaneous biopsy ($800) was lower than that of surgical biopsy ($3,419). The average per patient professional cost of percutaneous biopsy ($438) was also lower than that of surgical biopsy ($955). Savings averaged $3,136 per patient, or $1,376,622 for the study period.

CONCLUSION

Substantial health care cost savings may result by using a diagnostic algorithm in which percutaneous biopsy is the first strategy for establishment of a diagnosis in patients suspected of having abdominal malignancy.

Hypertension and years of driving in transit vehicle operators

In this study, data from transit vehicle operators of the San Francisco Municipal Railway (Muni), and a control group of individuals newly hired but not yet working as operators, were used to investigate prevalence of hypertension as a function of exposure to bus driving (years of driving), controlling for alcohol consumption and body mass index. Data were collected from transit vehicle operators in the course of their regular biennial examination during the period November 1983 to October 1985. Groups working as operators fewer than 10 years (n = 1137), from 10 to 20 years (n = 493), and more than 20 years (n = 196) were compared to each other and to a group of individuals with no prior exposure, but who were given a medical examination just before beginning their jobs as transit vehicle operators (n = 226). For hypertension (defined as systolic blood pressure > or = 140, or diastolic blood pressure > or = 90, or taking hypertension medication), the prevalence, adjusted for age, race, and gender, increased in a stepwise fashion from 28.8 percent in the group with no exposure to 38.9 percent in the group of drivers with more than 20 years on the job. A similar pattern was found for moderate to severe hypertension (systolic blood pressure > or = 160, or diastolic blood pressure > or = 95, or hypertension medication). These patterns were diminished, but not eliminated, when body mass index and alcohol consumption were considered. Higher rates of separation from employment for hypertensive operators suggested that the effect of years of employment may be underestimated by this cross-sectional comparison. Prolonged exposure to operating a transit vehicle may be associated with increased hypertension; increased alcohol consumption and body mass index with increased years of driving may account for at least some of the increased hypertension.

Reversible cerebral hypoperfusion in Lyme encephalopathy

Lyme encephalopathy (LE) presents with subtle neuropsychiatric symptoms months to years after onset of infection with Borrelia burgdorferi. Brain magnetic resonance images are usually normal. We asked whether quantitative single photon emission computed tomography (SPECT) is a useful method to diagnose LE, to measure the response to antibiotic therapy, and to determine its neuroanatomic basis. In 13 patients with objective evidence of LE, SPECT demonstrated reduced cerebral perfusion (mean perfusion defect index [PDI] = 255), particularly in frontal subcortical and cortical regions. Six months after treatment with 1 month of intravenous ceftriaxone, perfusion significantly improved in all 13 patients (mean PDI = 188). In nine patients with neuropsychiatric symptoms following Lyme disease, but without objective abnormalities (e.g., possible LE), perfusion was similar to that of the treated LE group (mean PDI = 198); six possible LE patients (67%) had already received ceftriaxone prior to our evaluation. Perfusion was significantly lower in patients with LE and possible LE than in 26 normal subjects (mean PDI = 136), but 4 normal subjects (15%) had low perfusion in the LE range. We conclude that LE patients have hypoperfusion of frontal subcortical and cortical structures that is partially reversed after ceftriaxone therapy. However, SPECT cannot be used alone to diagnose LE or determine the presence of active CNS infection.

Physical workload and ergonomic factors associated with prevalence of back and neck pain in urban transit operators

STUDY DESIGN

Back and neck pain was studied cross-sectionally in 1,449 urban transit drivers by linking medical data, self-reported ergonomic factors, and company records on job history.

OBJECTIVES

The goal was to examine the relation between physical workload, ergonomic factors, and the prevalence of back and neck pain.

SUMMARY OF BACKGROUND DATA

Researchers, to date, have not found an independent effect of ergonomic factors on back and neck pain while accounting for the effects of past and current physical workload.

METHODS

Self-reported ergonomic factors, vehicle type, physical workload (measured as duration of driving), height, weight, age, and gender were analyzed in relation to back and neck pain, using multivariable logistic regression models.

RESULTS

Physical workload showed a positive dose-response relation with back and neck pain after controlling for vehicle type, height, weight, age, and gender. The odds ratio for 10 years of driving was 3.43. Additional adjustment for ergonomic factors decreased this odds ratio to 2.55. Six out of seven ergonomic factors were significantly related to the prevalence of back and neck pain after adjustment for age, gender, height, weight, and physical workload. Problems with adjusting the seat had the largest effect (odds ratio = 3.52). Women had back and neck pain twice as frequently as men.

CONCLUSION

The results support the hypothesis of a causal role of physical workload for the development of back and neck pain. Ergonomic factors partially mediated the risk of back and neck pain associated with driving, suggesting a potential for prevention of back and neck pain by ergonomic redesign of transit vehicles. Elevated risks for back and neck pain for female drivers were not explained by anthropometric and ergonomic factors.

A technetium-99m SPECT imaging agent which targets the dopamine transporter in primate brain

The dopamine transporter (DAT), located presynaptically on dopamine neurons, provides a marker for certain neurological diseases. In particular, the DAT is depleted in Parkinson's disease, and the extent of depletion correlates with the loss of dopamine. Herein we describe the design, synthesis, and biological evaluation of technepine, the first 99mTc-labeled SPECT imaging agent which targets the dopamine transporter in striatum. We have demonstrated that the DAT can accommodate a chelating unit attached to the 8-amine function of a tropane skeleton. Further, we have demonstrated for the first time that a molecule can be designed to carry the radionuclide 99mTc across the blood-brain barrier in sufficient quantity to obtain in vivo images of the striatum in monkeys. This advance will undoubtedly lead to the design of new receptor and transporter-mediated 99mTc agents which can label specific transporter and receptor targets in the central nervous system.

Expediting the turnaround of radiology reports in a teaching hospital setting

OBJECTIVE

The purpose of this study was to determine whether total quality management (TQM) techniques that had proved successful in a pilot study in one departmental section of a teaching hospital could be generalized for use by the entire radiology department.

MATERIALS AND METHODS

Each departmental section developed interventions to improve its report turnaround time. These interventions were tailored to practice style and habits of each section. Commonly used interventions included electronic signature from the radiologist's home, a report-signing buddy system, elimination of a trainee signature requirement, accelerated transcription, structured reports, faster film delivery to reading desks, and training about the importance of radiology reports for clinical decision making. Specialized programs included computerized form-driven reporting and reports generated directly by computer voice recognition of radiologists' dictation. Our radiology information system provided data on each step in the reporting process.

RESULTS

The TQM approach produced significant improvements in departmental total report turnaround time (-55%; p = .001), transcription time (-80%; p = .003), and signature time (-68%; p = .0004). Each section achieved significant gains. The sonography section initiated a computerized, form-driven reporting system and outperformed the rest of the department.

CONCLUSIONS

TQM techniques can be expanded and generalized for department-wide projects in teaching hospitals.

Functional imaging in treatment planning of brain lesions

PURPOSE

Explore the use of functional imaging data in radiation treatment planning of brain lesions.

METHODS AND MATERIALS

Compare the treatment-planning process with and without the use of functional brain imaging for clinical cases where functional studies using either single photon emission computed tomography or magnetic resonance imaging are available.

RESULTS

A method to register functional image data with planning image studies is needed for functional treatment planning. Functional volumes are not simply connected regions. One activation study may produce many isolated functional areas. After finding the functional volumes and registering the functional information with the planning imaging data, the tools used for conventional three-dimensional treatment planning are sufficient for functional treatment planning. However, the planning system must provide dose-volume histograms for volumes of interest that consist of isolated pieces. Treatment plans that spare functional brain while providing identical target coverage can be constructed for lesions situated near the functional volume. However, the dose to other areas of the brain may be increased.

CONCLUSIONS

Functional imaging will make determination of dose response of eloquent areas of the brain possible when combined with volumetric dose information and neuropsychological evaluation prior to and after radiation therapy. Realizing the full potential of functional imaging studies will require improved delineation of activated volumes and determination of the uncertainties in functional volume delineation. Optimization of treatment plans by minimizing dose to volumes activated during functional imaging studies should be used cautiously, because the dose to "silent," but possibly eloquent, brain may be increased.

Finding the Path: a World Wide Web-based guide for imaging evaluation of patients in the emergency department

Finding the Path is a problem-based World Wide Web resource that provides algorithms for imaging evaluation of emergency department patients. This module is designed to guide physicians in the efficient use of diagnostic imaging modalities and their appropriate application to emergency department practice. The module is composed of interactive case studies that can be accessed either by diagnoses or as unknowns. Each case study provides a brief clinical history accompanied by pertinent physical and laboratory findings. Users are asked to choose the most appropriate and cost-effective diagnostic imaging study and receive feedback on their choice. Associated images, findings, and a brief discussion of the diagnosis are displayed. Each case is followed by an algorithm aimed at promoting efficient and cost-effective use of imaging modalities. In addition to its value in clinical practice, the database is a useful radiologic teaching tool for residents and medical students. The module is being used at a major university as part of the new curriculum for radiologic education.

Achievement of substantial cost reduction through joint purchasing by the radiology departments of a large vertically integrated health care system

RATIONALE AND OBJECTIVES

The authors sought to lower costs by coordinating the purchase of equipment, supplies, and services in the radiology departments of a vertically integrated health system formed by the merger of two of the largest academic medical centers in New England.

METHODS

The radiology departments at Massachusetts General Hospital and Brigham & Women's Hospital formed a cost-reduction task force to explore opportunities to jointly decrease costs. Data from the operating budgets of both institutions were collected and analyzed to find specific items within the budgets that could yield substantial cost savings.

RESULTS

The project's first phase yielded over $810,000 in reduced costs from a system-wide annual budget of only $7 million for film and contrast material. Ongoing additional projects suggest that longer term contracts that contain steeper discounts with a decreased number of vendors will result in further decreases in the cost of materials and supplies.

CONCLUSION

Coordination of purchasing by the radiology members of an integrated delivery system can yield substantial savings.

Focal brain dysfunction in a 41-year old man with familial alternating hemiplegia

The acute pathophysiologic changes during hemiplegic spells and the long-term outcome of alternating hemiplegia remain obscure. In a 41-year-old male with familial alternating hemiplegia we found an increase in right frontal cerebral blood flow 3 h into a 5-h left hemiplegic episode. A repeat high-resolution brain SPECT study performed 26 h after the resolution of the left hemiplegia revealed normalization of the frontal blood flow accompanied by hyperperfusion in the right parietal lobe. An interictal SPECT scan several weeks later showed no asymmetries. Head CT and MRI scans were negative. Neuropsychologic assessment and neurologic examination revealed evidence of a diffuse disorder which predominantly involved the right hemisphere. To our knowledge, there are no previous correlative studies of serial high-resolution brain SPECT with MRI, or of detailed neuropsychologic assessment, in adult patients with such an advanced course of alternating hemiplegia of childhood.

Focal cerebral perfusion defects demonstrated by 99mTc-hexamethylpropyleneamine oxime SPECT in elderly depressed patients

High resolution single photon emission computed tomography (SPECT) was used to evaluate regional cerebral blood flow (rCBF) in 14 acutely depressed elderly patients and 29 normal subjects. SPECT images of the two groups were randomized and blindly read. Foci of decreased radionuclide uptake were assessed by number and location. The total number of rCBF defects per whole brain study was significantly greater in the depressed patients than in the normal subjects. A significantly greater number of rCBF defects was found most strikingly in the lateral frontal and less prominently in the lateral and medial temporal brain regions of the depressed patients.

Abnormal cerebral metabolism in polydrug abusers during early withdrawal: a 31P MR spectroscopy study

Phosphorus magnetic resonance spectroscopy (31P MRS) at 1.5 T was performed on nine polysubstance abusing men. All nine patients met DSM-III-R criteria for concurrent cocaine and heroin dependence, were neurologically normal, were negative for the human immunodeficiency virus, and had normal clinical brain MRI scans. Patients were scanned 2-7 days after admission to a drug treatment unit. Eleven age-matched control subjects also were studied. The ISIS localized phosphorus spectra were obtained from a 5-cm thick axial brain slice and a 100-cc white matter volume. In the brain slice, the phosphorus metabolite signal expressed as a percentage of total phosphorus signal was 15% higher for phosphomonoesters, 10% lower for nucleotide triphosphates (beta-NTP), and 7% lower for total nucleotide phosphates in polydrug abusers compared with those in controls. Phosphodiesters, inorganic phosphate, phosphocreatine, total phosphorus, pH, and free magnesium concentration were unchanged. None of these parameters correlated with the methadone dose or the number of days abstinence. Single photon emission computed tomographic imaging of a subgroup of the patients revealed abnormal cerebral perfusion in 80% of the patients scanned. These data suggest that cerebral high energy phosphate and phospholipid metabolite changes result from long term drug abuse and/or withdrawal and that these changes can be detected and studied by 31P MRS.

Collaboration using Internet for the development of case-based teaching files: report of the Computer and Instrumentation Council Internet Focus Group

The Internet and particularly the World-Wide-Web is becoming a useful tool for the nuclear medicine community.

METHODS

The Computer and Instrumentation Council of the Society of Nuclear Medicine convened an Internet Focus group to discuss collaboration using the Internet. The prototype application considered was development of case-based teaching files using the World-Wide-Web. Teaching file cases (clinical history, images, description of findings and discussion) on World-Wide-Web servers at different institutions are integrated using the Internet. The user can navigate from case to case using point-and-click hypertext linking.

RESULTS

The initial experience with collaboration has been encouraging. An etiquette to help foster collaboration has been proposed. Development of quality control mechanisms and introduction of peer review were identified as issues needing further work.

CONCLUSION

The World-Wide-Web offers great potential for new forms of collaboration. There is, however, a need to learn how to make best use of this new resource.

Inside BrighamRAD: providing radiology teaching cases on the Internet

The Internet provides opportunities for widely distributing educational materials such as teaching files. Since a teaching file is both a tradition and a requirement in an accredited diagnostic radiology training program, many of the same resources can be committed to designing it for Internet access. The advantages include easier availability for the department residents and fellows, communication to a wider audience, the opportunity for networking and collaboration with other institutions during development, and making information available for more rapidly than traditional publications. Since material available on the Internet represents an alternative means of publication, all cases in an electronic teaching file, as is the case with BrighamRad, should be subject to peer review. A successful computer-based teaching file requires department-wide commitment of trainees and staff as well as additional expertise in multimedia instruction, computer-based graphics and design, image manipulation, programming, and database management. Quality efforts take time and require continual adaptation and support as technology and the laws and customs governing the use of electronically published material evolve. The process should be ongoing, and the departmental commitment must be long term and continuous.

Occupational and nonoccupational correlates of alcohol consumption in urban transit operators

BACKGROUND

The influence of occupation and the worksite has emerged as an important area of study in research on alcohol consumption. Occupational and nonoccupational factors were studied in relation to alcohol consumption using data from a 1983-1985 cross-sectional study of transit operators.

METHODS

A total of 1.853 operators underwent a medical examination for driver's license renewal (including information on age, ethnicity, gender, education). Of these operators, 1,448 completed a questionnaire about occupational (e.g., time of shift, job stressors) and nonoccupational (e.g., personality, life stressors) factors. From either the medical examination or the questionnaire, weekly alcohol consumption was available for 1,820 operators. Variables related to alcohol consumption in previous studies, or theoretically linked to consumption, were analyzed in relation to heavy ( > or = 15 drinks/week) and average weekly consumption.

RESULTS

Heavy and average consumption were both related to several nonoccupational variables, including demographic (age, ethnicity, gender, marital status), personality (depression, anger expression), and life stress variables (i.e., life events). Heavy and average consumption were also related to several occupational variables, including job history (number of years driving, specific worksite) and job stressors. Neither measure was related to subjective job content (job demand, decision latitude).

CONCLUSIONS

Variability in consumption by demographic factors among this population reflects that seen in society as a whole. However, occupational factors may influence consumption, since consumption was strongly related to (a) specific worksite and time of shift and (b) reported job stressors. Clarifying the exact influence of occupational and worksite factors on alcohol consumption will depend on the convergence of findings from different research designs (e.g., cross-sectional, longitudinal, ethnographic).

Improved regional cerebral blood flow in chronic cocaine polydrug users treated with buprenorphine

Chronic cocaine and polydrug abuse have been associated with regional abnormalities in cerebral perfusion. The authors have previously demonstrated that these abnormalities are partially reversible after drug addiction treatment with buprenorphine. This study was designed to separate the effect on cerebral perfusion of abstinence from drug use from that of buprenorphine directly.

METHODS

Fifteen cocaine- and heroin-dependent men were studied with 99mTc-hexamethylpropyleneamine oxime (HMPAO) brain SPECT. The men, all part of an inpatient drug abuse treatment research program, were randomly assigned after detoxification to receive placebo or either 6 or 12 mg daily buprenorphine treatment. SPECT studies were performed at baseline, after maximum dosage was reached and after tapering off the study drug. Studies were compared visually with regard to the number and location of perfusion defects by reviewers blinded to treatment assignment.

RESULTS

Subjects receiving buprenorphine had a significant reduction in the number of defects per study between baseline and maximum buprenorphine dose as compared with those receiving placebo (decrease of 4 +/- 5.4 versus increase of 4.8 +/- 4.7, p = 0.006). These differences were dose-related. Improvement with buprenorphine was temporary, with return to baseline after tapering off.

CONCLUSION

Buprenorphine treatment, and not abstinence from drug use alone, leads to improvement in regional cerebral perfusion abnormalities in chronic cocaine- and heroin-dependent men.

SPECT perfusion imaging in the diagnosis of dementia

Single-photon emission computed tomography (SPECT) imaging has provided the practicing clinician with a method of studying brain function in patients with dementia. A large and growing number of papers report the experiences of a number of laboratories in the use of this technique in the evaluation of demented patients. Studies from several laboratories comparing patients with Alzheimer's disease to control subjects report sensitivity and specificity of SPECT perfusion imaging to be in the 80% vicinity. In addition, a number of studies suggest that the dementias that show the greatest similarities in perfusion patterns to Alzheimer's disease are multi-infarct dementia and dementia associated with Parkinson's disease. Although considerable data exists to guide the physician, a rigorous scientific approach to studying patients in a prospective, unselected clinical sample, with autopsy confirmation of the diagnosis, is needed to define clearly the utility of the technique in diagnosing dementias.

Gender differences in cerebral perfusion in cocaine abuse: technetium-99m-HMPAO SPECT study of drug-abusing women

Cocaine abuse continues to be a major public health concern, with a variety of medical and neurologic sequelae. Previous studies have demonstrated abnormalities in cerebral perfusion in chronic cocaine abusers and after acute administration of cocaine. Although women are becoming increasingly represented among drug abusers, few studies have included women. To the authors' knowledge, none has compared cerebral perfusion in asymptomatic women with that in men.

METHODS

The cerebral perfusion of 13 cocaine-dependent women, 4 of whom were also heroin dependent, was studied with 99mTc hexamethylpropyleneamine oxime (HMPAO) SPECT. These women were compared with 13 cocaine-dependent men and 26 healthy control subjects. Structural brain lesions and neurologic abnormalities were excluded by MRI and neurologic evaluation. Perfusion studies were interpreted in a standardized fashion by reviewers blinded to clinical information.

RESULTS

It was found that cocaine-dependent women were much less likely to have abnormal study findings than cocaine-dependent men (p = 0.003) and were indistinguishable from normal women (p = 1.0). However, the results in both women and men who concurrently used heroin plus cocaine were all abnormal. Perfusion abnormalities tended to be located in anterior brain structures, such as the frontal and temporal cortex and the basal ganglia.

CONCLUSION

These data suggest that cocaine-dependent women have fewer abnormalities in cerebral perfusion than cocaine-dependent men, but that concurrent abuse of heroin and cocaine is associated with more perfusion abnormalities in both sexes.

Brain single-photon emission computed tomography

Single-photon emission computed tomography (SPECT) provides cost-effective information on regional cerebral perfusion and, indirectly, on regional cerebral metabolism. Its ease of use facilitates the application of SPECT in clinical neurology. SPECT is emerging as a useful tool for the management of patients with stroke, epilepsy, recurrent brain neoplasms, and some forms of dementia. The applications being investigated, such as in vivo receptor labeling for benzodiazepines, serotonin, dopamine, and muscarinic receptors, may expand the clinical usefulness of this technique in the future.

Early and delayed brain SPECT with technetium-99m-ECD and iodine-123-IMP in subacute strokes

The brain distribution of 99mTc-ECD versus 123I-IMP was compared in patients with subacute stroke in order to compare diagnostic accuracy.

METHODS

A total of 25 patients with subacute stroke underwent early and delayed SPECT imaging with 99mTc-ECD and 123I-IMP. Washout of 99mTc-ECD was calculated and a differential percentage of activity (DPA) of ischemic versus normal zones was assessed. Images were analyzed twice by five independent observers.

RESULTS

Technetium-99m-ECD clearance was 12.5% from the whole brain during early imaging. Ischemic parietal zones had higher clearance than normal parietal zones. Technetium-99m-ECD images showed larger differences between abnormal and normal brain activity than 123I-IMP images. Detection accuracy was slightly, but not significantly, higher for 99mTc-ECD and 123I-IMP (sensitivity: 73.8% as 66.6%; specificity: 81.7% as 81.6%). Reproducibility among observers was similar for 99mTc-ECD and early 123I-IMP.

CONCLUSION

Technetium-99m-ECD demonstrates high diagnostic accuracy during subacute stroke, similar to 123I-IMP, but with more intense, better delineation of the perfusion defects.

Medical impact of unedited preliminary radiology reports

PURPOSE

To determine the potential frequency of adverse patient outcomes resulting from erroneous preliminary radiology reports.

MATERIALS AND METHODS

The authors determined the number of preliminary radiology reports that changed substantively between the preliminary and final version during a 10-day collection period. They analyzed 200 of 1,648 reports to determine the potential for adverse outcome.

RESULTS

Only 5.6% of the preliminary radiology reports were changed substantively. Two percent of all reports contained changes that would have led to additional testing or treatment and, possibly, increased morbidity.

CONCLUSION

Immediate electronic transfer of a preliminary radiology report results in a small but important number of adverse outcomes; however, if a final edited report follows within 24 hours and referring physicians are called whenever the preliminary report contains erroneous information, the benefits of rapid information transmission may outweigh the additional risks.

Hyperperfusion of ictal seizure focus demonstrated by MR perfusion imaging

MR using a susceptibility-weighted sequence and dynamic contrast enhancement with gadolinium demonstrated relative hyperperfusion of the right temporoparietal cortex in a patient in focal status epilepticus. A single-photon emission CT (SPECT) scan also demonstrated hyperperfusion of the right temporoparietal cortex. Perfusion MR, SPECT, and electroencephalogram normalized when the seizures ended.

A neural network classifier for cerebral perfusion imaging

Artificial neural networks have been applied to a variety of pattern recognition tasks in medical imaging and have been shown to be a powerful classification tool. The potential usefulness to discriminate normal from abnormal cerebral perfusion patterns was investigated.

METHODS

Cerebral perfusion imaging with 99mTc-labeled hexamethylpropyleneimine oxime was performed on 52 normal control subjects, 29 patients with clinically diagnosed Alzheimer's disease (AD) and 25 patients with chronic cocaine polydrug abuse. Each study was registered and scaled to a common anatomic coordinate system, yielding 120 standardized cortical regions. A back-propagation neural network classifier based on regional perfusion was used to classify normal and abnormal perfusion patterns. The neural network was trained to discriminate patients with AD from age-matched normal controls and cocaine polydrug abuse patients from normal controls. The performance of the neural network in these two tasks was evaluated quantitatively by receiver operating characteristic (ROC) analysis using cross-validation.

RESULTS

For patients with AD, the area under the ROC curve was 0.93 +/- 0.04. When testing with the cocaine polydrug abuser data, the area under the ROC curve was 0.89 +/- 0.04.

CONCLUSION

Neural networks provide a potentially useful tool in the decision-making task to discriminate patients with AD and cocaine abuse from normal controls.

In vivo metabolism of the technetium isonitrile complex [Tc(2-ethoxy-2-methyl-1-isocyanopropane)6]+

Technetium(2-ethoxy-2-methyl-1-isocyanopropane)6+, [Tc-EIBT] is a complex of technetium(I) structurally similar but slightly more lipophilic than the commercial myocardial perfusion agent Cardiolite [Tc-MIBI]. Tc-EIBI exhibits rapid extraction from the blood into heart, liver, kidney and striated muscle and rapid hepatobiliary clearance. In the guinea pig, unlike Tc-MIBI, this compound is almost completely enzymatically metabolized to numerous cationic complexes containing a mixture of ethyl other and hydroxy isonitrile ligands. Substitution of the ethyl other group for a methyl ether produces an agent that shows selective in vivo metabolism and more rapid clearance from the liver.

Detection of intracranial abnormalities in patients with chronic fatigue syndrome: comparison of MR imaging and SPECT

OBJECTIVE

Chronic fatigue syndrome is a recently characterized condition of unknown origin that is manifested by fatigue, flulike complaints, and neurologic signs and symptoms, including persistent headache, impaired cognitive abilities, mood disorders, and sensorimotor disturbances. This syndrome can be difficult to diagnose clinically or by standard neuroradiologic tests. We performed MR imaging and single-photon emission computed tomography (SPECT) in patients with chronic fatigue syndrome to compare the usefulness of functional and anatomic imaging in the detection of intracranial abnormalities.

SUBJECTS AND METHODS

Sixteen patients who fulfilled the Centers for Disease Control, British, and/or Australian criteria for chronic fatigue syndrome had MR and SPECT examinations within a 10-week period. Axial MR and SPECT scans were analyzed as to the number and location of focal abnormalities by using analysis of variance with the Student-Newman-Keuls option. MR imaging findings in patients with chronic fatigue syndrome were compared with those in 15 age-matched control subjects, and SPECT findings in the patients with chronic fatigue syndrome were compared with those in 14 age-matched control subjects by using Fisher's exact test. The findings on MR and SPECT scans in the same patients were compared by using the Wilcoxon matched-pairs signed-ranks test.

RESULTS

MR abnormalities consisted of foci of T2-bright signal in the periventricular and subcortical white matter and in the centrum semiovale; there were 2.06 foci per patient, vs 0.80 foci per control subject. MR abnormalities were present in eight (50%) of 16 patients, compared with three (20%) of 15 age-matched control subjects. Neither of these differences reached significance, although the power of the study to detect differences between groups was small. Patients with chronic fatigue syndrome had significantly more defects throughout the cerebral cortex on SPECT scans than did normal subjects (7.31 vs 0.43 defects per subject, p < .001). SPECT abnormalities were present in 13 (81%) of 16 patients, vs three (21%) of 14 control subjects (p < .01). SPECT scans showed significantly more abnormalities than did MR scans in patients with chronic fatigue syndrome (p < .025). In the few patients who had repeat SPECT and MR studies, the number of SPECT abnormalities appeared to correlate with clinical status, whereas MR changes were irreversible.

CONCLUSION

SPECT abnormalities occur more frequently and in greater numbers than MR abnormalities do in patients with chronic fatigue syndrome. SPECT may prove to be useful in following the clinical progress of patients with this syndrome.

SPECT imaging of the brain: comparison of findings in patients with chronic fatigue syndrome, AIDS dementia complex, and major unipolar depression

OBJECTIVE

Chronic fatigue syndrome is an illness of unknown origin that begins abruptly with a flulike state and has symptoms suggesting both a chronic viral encephalitis and an affective disorder. We compared single-photon emission computed tomography (SPECT) scans of patients with chronic fatigue syndrome with those of patients with AIDS dementia complex and unipolar depression.

SUBJECTS AND METHODS

We used 99mTc-hexamethylpropyleneamine oxime to examine 45 patients with chronic fatigue syndrome, 27 patients with AIDS dementia complex, and 14 patients with major unipolar depression. Scans of 38 healthy persons were used as controls. Comparison of regional defects between groups, as well as midcerebral uptake indexes (an objective measure of global radionuclide uptake), was performed by using analysis of variance with the Student-Newman-Keuls option. Correlation between the number of regional defects and the midcerebral uptake index was determined by using the Spearman rank-correlation test.

RESULTS

Patients with AIDS dementia complex had the largest number of defects (9.15 per patient) and healthy patients had the fewest defects (1.66 per patient). Patients with chronic fatigue syndrome and depression had similar numbers of defects per patient (6.53 and 6.43, respectively). In all groups, defects were located predominantly in the frontal and temporal lobes. The midcerebral uptake index was found to be significantly lower (p < .002) in the patients with chronic fatigue syndrome (.667) and patients with AIDS dementia complex (.650) than in patients with major depression (.731) or healthy control subjects (.716). Also, a significant negative correlation was found between the number of defects and midcerebral uptake index in patients with chronic fatigue syndrome and AIDS dementia complex, but not in depressed patients or control subjects.

CONCLUSION

These findings are consistent with the hypothesis that chronic fatigue syndrome may be due to a chronic viral encephalitis; clinical similarities between chronic fatigue syndrome and depression may be due to a similar distribution and number of defects in the two disorders.

Mitochondrial localization and characterization of 99Tc-SESTAMIBI in heart cells by electron probe X-ray microanalysis and 99Tc-NMR spectroscopy

As the development of targeted intracellular magnetic resonance contrast agents proceeds, techniques for the quantitative analysis of the subcellular compartmentation and characterization of metallopharmaceuticals must also advance. To this end, the subcellular distribution and chemical state of hexakis (2-methoxyisobutyl isonitrile) technetium-99 (99Tc-SESTAMIBI), the ground state of the organotechnetium radiopharmaceutical used for the noninvasive evaluation of myocardial perfusion and viability by scintigraphy, has been determined by a novel application of electron probe X-ray microanalysis (EPXMA) and 99Tc-NMR spectroscopy. In cryopreserved cultured chick heart cells equilibrated in 36 microM 99Tc-SESTAMIBI, EPXMA imaging of mitochondria yielded a respiratory uncoupler-sensitive characteristic 99Tc X-ray peak representing 32.0 +/- 2.9 nmoles Tc/mg dry weight, while EPXMA of cytoplasm or nucleus showed no peak significantly greater than the threshold detectability limit of approximately 1 nmole/mg dry weight. Technetium-99 NMR spectroscopy of heart cells equilibrated with 99Tc-SESTAMIBI showed a single peak at -45.5 ppm with no evidence of significant line broadening or chemical shift compared to aqueous chemical standards, indicating that the majority of the complex exists unbound within the mitochondrial matrix. These data quantitatively demonstrate the localization of this lipophilic cationic organometallic complex within mitochondria in situ, consistent with a sequestration mechanism dependent on membrane potentials. Furthermore, this study establishes the general feasibility of combined EPXMA and NMR spectroscopy for the direct subcellular localization and characterization of metallopharmaceuticals, techniques that are readily applicable to MR contrast agents.

Tc-99m HMPAO brain perfusion SPECT in acute aphasia. Correlation with clinical and structural findings

Tc-99m hexamethylpropylene amineoxime (HMPAO) brain perfusion SPECT was correlated with CT, MRI, and clinical findings in 17 patients with acute and subacute aphasia to determine its diagnostic potential in the early phases of stroke-associated language dysfunction. SPECT was performed using a dedicated brain imaging system after intravenous injection of 20 mCi (740 MBq) of Tc-99m HMPAO. Transaxial and three-dimensional surface rendered images were evaluated visually, and perfusion defects were correlated with CT, MRI, and a standard battery of clinical tests for aphasia. Clinical examination was insufficient for anatomic localization of aphasia in more than 40% of patients. CT exams were normal in 5 patients, although SPECT demonstrated perfusion defects in all 17. Nonfluent aphasia was present in only 6 of 10 patients with perfusion defects in Broca's area and fluent aphasia was present in only 5 of 10 patients with lesions in Wernicke's area. Auditory comprehension defect was associated with perfusion defects in the inferior parietal region in 9 of 12 patients (P = 0.05); reading and writing abnormalities were associated with perfusion defects in the posterior frontal, superior and inferior parietal cortex, and superior temporal gyri, and repetition deficit was associated with defects involving the inferior parietal cortex, the supramarginal and angular gyri, and the ipsilateral thalamus in 8 of 11 patients (P < 0.05). Brain perfusion SPECT should be included in the initial evaluation of aphasic patients, because clinical tests of aphasia and morphological imaging have limited value for accurately determining the extent and location of functional deficits.

Quantitative brain SPECT in Alzheimer's disease and normal aging

To improve the diagnostic utility of brain single-photon emission computed tomography (SPECT) in Alzheimer's disease (AD), we have developed and evaluated an objective method of differentiating patients and healthy elderly controls using a quantitative image analysis protocol. HMPAO-SPECT image datasets from 29 patients with probable AD and 78 age-matched controls were registered to a common anatomic frame of reference. Activity levels within 120 standardized cortical volumes were determined by an automated procedure. Subjects were classified into normal and AD groups by quadratic discriminant analysis using two features: global average activity level and average normalized activity levels within the two clusters of standardized volumes identified as most significantly different in AD by analysis of covariance. The classification used split-half replication to ensure valid results. Classification performance quantified by the area under a binormal ROC curve fitted to the data was 0.923 +/- 0.036; at a threshold likelihood ratio of 1, the sample sensitivity was 91% and specificity was 86%. We conclude that quantitative SPECT accurately distinguishes AD patients from elderly controls.