Causes of death among United States decedents with ALS : An eye toward delaying mortality

OBJECTIVE

To report multiple cause of death (MCOD) occurrence among patients in the United States with amyotrophic lateral sclerosis (ALS).

METHODS

Using death certificate data for all ALS deaths from 50 U.S. states and the District of Columbia, 2011-2014, we tabulated MCOD, used association rules mining (ARM) to determine if MCOD occurred together, and calculated standardized mortality odds ratios (SMOR) for select causes, comparing ALS with other U.S. decedents.

RESULTS

Among 24,328 death certificates, there were 25,704 MCOD, excluding ALS. ALS was listed as the sole cause of death in n = 11,263 (46%). The most frequent causes of death co-occurring with ALS were respiratory failure (n = 6503; 25.3%), cardiovascular disease (n = 6077; 12.6%), pneumonia (n = 1345; 5.2%), and pneumonitis (n = 856; 3.3%). The SMORs among ALS decedents compared with non-ALS decedents for falls and accidents were 3.4 (95% CI 2.6, 4.3) and 3.0 (95% CI 2.2, 4.2), respectively. From ARM analysis, falls and accidents were both associated with injuries. The most common causes identified were weakly to very strongly associated with being an ALS decedent compared with other U.S. deaths, with SMOR point estimates ranging from 1.3 to 51.1.

INTERPRETATION

This study provides information about the natural history of ALS. With knowledge that some causes of death may be preventable, healthcare providers may be able to optimize patient care and possibly postpone mortality and reduce morbidity. Moreover, this study located gaps in data; medical certifiers completing death certificates for ALS decedents should ensure all MCOD data are recorded.

Survival and epidemiology of amyotrophic lateral sclerosis (ALS) cases in the Chicago and Detroit metropolitan cohort: incident cases 2009-2011 and survival through 2018

Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disorder. The National ALS Registry launched surveillance projects to understand the distribution of ALS in targeted geographic cohorts. Objective: To describe the demographics, incidence, and survival of persons with ALS (PALS) identified in the Chicago and Detroit area population-based cohort. Methods: Neurologists in the catchment area provided case reports for eligible ALS cases diagnosed and/or cared for from 1 January 2009 through 31 December 2011. Crude incidence rates were calculated for 2009-2011 and stratified by race and ethnicity. Using data from the National Death Index through 2018, we modeled the effect of patient covariates on mortality using the Cox proportional hazard regression. Results: Of the 574 cases, 372 (64.8%) were diagnosed from 2009 to 2011. The combined crude incidence rates for 2009, 2010, and 2011 were 1.44, 1.53, and 1.73 cases per 100,000 person-years, respectively. Of the 486 subjects with complete survival data, 81% were deceased at the end of follow-up. Median survival time was 2.2 years, with 30% and 9% of subjects surviving past 5 and 10 years after diagnosis, respectively. Additionally, female PALS and PALS with longer time between symptom onset and diagnosis experienced longer survival. Nonwhites also experienced longer survival than Whites, except for those cases diagnosed in the younger age categories. Conclusion: Understanding the survival of ALS patients can aid in understanding variable prognostic factors, which can potentially extend survival and improve disease management.

Recruitment of population-based controls for ALS cases from the National ALS Registry

Objective:

In 2010, the United States Agency for Toxic Substances and Disease Registry (ATSDR) created the National ALS Registry (Registry) to examine the epidemiology of ALS and potential risk factors. We are currently recruiting population-based controls for an epidemiologic case-control study to examine ALS environmental risk factors using this Registry. To date, we have recruited 181 non-diseased, population-based controls for comparison to Registry cases (n = 280). Here we report our recruitment methods for controls and the associated response rates and costs.

Methods:

Eligible ALS cases had complete risk factor survey data, DNA analysis, and blood concentrations of persistent organic pollutants (POPs). Age, sex, and county-matched controls were identified from commercial/consumer databases using a targeted landline phone sample. Eligible controls were consented, surveyed, and mailed the POPs’ blood analysis consent form. Once consented, phlebotomy was scheduled.

Results:

We mailed 3760 recruitment letters for 181 potential case-matches across 42 states between 9/2018 and 3/2020. After making phone contact and determining eligibility, 146 controls agreed to participate (response rate = 11.4%, cooperation rate = 22.8%). To date, 127 controls completed the survey and bloodwork. Though controls were matched to cases on age, sex, and county, unmatched characteristics (e.g. smoking) did not differ statistically. Interviewing and incentive costs are estimated at $211.85 per complete participation.

Conclusions:

Recruiting matched population-based controls for comparison to cases from the Registry for a study involving completion of a detailed survey and blood specimen provision is relatively feasible and cost effective. This recruitment method could be useful for case-control studies of other rare disorders.

Geographic Co-Occurrence of Mesothelioma and Ovarian Cancer Incidence

Background: Asbestos is an established cause of several cancers, including mesothelioma and ovarian cancer. Incidence of mesothelioma, the sentinel asbestos-associated cancer, varies by state, likely reflecting different levels of asbestos exposure. We hypothesized that states with high mesothelioma incidence may also have high ovarian cancer incidence. Materials and Methods: Using data from the Centers for Disease Control and Prevention National Program for Cancer Registries and the National Cancer Institute Surveillance, Epidemiology, and End Results Program, we examined the geographic co-occurrence of mesothelioma and ovarian cancer incidence rates by U.S. state for 2003-2015. Results: By state, mesothelioma incidence ranged from 0.5 to 1.3 cases per 100,000 persons and ovarian cancer incidence ranged from 9 to 12 cases per 100,000 females. When states were grouped by quartile of mesothelioma incidence, the average ovarian cancer incidence rate was 10% higher in states with the highest mesothelioma incidence than in states with the lowest mesothelioma incidence. Ovarian cancer incidence tended to be higher in states with high mesothelioma incidence (Pearson correlation r = 0.54; p < 0.0001). Conclusions: Data from state cancer registries show ovarian cancer incidence was positively correlated with mesothelioma incidence, suggesting asbestos may be a common exposure. The potential for asbestos exposure has declined since the 1970s because fewer products contain asbestos; however, some products, materials, and buildings may still release asbestos and thousands of workers may be exposed. Ensuring that people are protected from exposure to asbestos in their workplaces, homes, schools, and communities may reduce the risk of several cancers.

Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study

OBJECTIVE

To evaluate mortality patterns among participants in a community-based screening program for asbestos-related disease.

METHODS

We calculated standardized mortality ratios (SMRs) and stratified results by exposure group (three occupational exposure groups, household contacts and residents without occupational asbestos exposure) and by radiographic abnormality presence.

RESULTS

All-cause mortality (15.8%; 1,429/8,043) was statistically lower than expected. Asbestosis was statistically elevated in all exposure groups. Lung cancer was moderately associated with vermiculite miner/miller employment. Mesothelioma was elevated in that same exposure group and among residents. Systemic autoimmune disease mortality was also elevated. Radiographic parenchymal abnormalities were associated with lung cancer mortality.

CONCLUSION

In addition to asbestos-related mortality in occupational exposure groups, this initial follow-up of this cohort also shows elevated mortality for some asbestos-related causes in non-occupational exposure groups.

Amyotrophic Lateral Sclerosis Mortality in the United States, 2011-2014

BACKGROUND

The International Classification of Disease, 10th Revision (ICD-10) did not include a code specific for Amyotrophic lateral sclerosis (ALS) until 2017. Instead, code G12.2 included both ALS and other motor neuron diseases (MND). Our objective was to determine US mortality rates for ALS exclusively by excluding other MND and progressive supranuclear palsy.

METHODS

All mortality data coded as G12.2 under the pre-2017 rubric were obtained for 2011-2014. Deaths without ALS listed in one of the un-coded cause-of-death fields were excluded. ALS death rates per 100,000 persons were age-adjusted to the 2000 US standard population using the direct method.

RESULTS

The proportion of excluded records coded G12.2 but not ALS was 0.21, resulting in 24,328 ALS deaths. The overall age-adjusted mortality rate was 1.70 (95% CI 1.68-1.72). The rate among males was 2.09 (95% CI 2.05-2.12) and females was 1.37 (95% CI 1.35-1.40). The overall rate among whites was 1.84, blacks 1.03, and other races 0.70. For both sexes and all races, the rate increased with age and peaked among 75-79 year-olds. Rates tended to be greater in states at higher latitudes.

CONCLUSIONS

Previous reports of ALS mortality in the United States showed similar age, sex, and race distributions but with greater age-adjusted mortality rates due to the inclusion of other diseases in the case definition. When using ICD-10 data collected prior to 2017, additional review of multiple-cause of death data is required for the accurate estimation of ALS deaths.

Intraprocedural predictors of post-stent retriever thrombectomy subarachnoid hemorrhage in middle cerebral artery stroke

BACKGROUND

Stent retriever thrombectomy (SRT) in acute thromboembolic stroke can result in post-thrombectomy subarachnoid hemorrhage (PTSAH). Intraprocedural findings associated with PTSAH are not well defined.

OBJECTIVE

To identify angiographic findings and procedural factors during SRT that are associated with PTSAH.

MATERIALS AND METHODS

This was a retrospective, observational cohort study of consecutive patients with middle cerebral artery (MCA) acute ischemic stroke treated with SRT. Inclusion criteria were: (1) age ≥18 years; (2) thromboembolic occlusion of the MCA; (3) at least one stent retriever pass beginning in an M2 branch; (4) postprocedural CT or MRI scan within 24 hours; (5) non-enhanced CT Alberta Stroke Program Early CT Score >5. Exclusion criteria included multi-territory stroke before SRT.

RESULTS

Eighty-five patients were enrolled; eight patients had PTSAH (group 1) and 77 did not (group 2). Baseline demographic and clinical characteristics were comparable between the two groups. In group 1, a significantly greater proportion of patients had more than two stent retriever passes (62.5% vs 18.2%, P=0.01), a stent retriever positioned ≥2 cm along an M2 branch (100% vs 30.2%, P=0.002), and the presence of severe iatrogenic vasospasm before SRT pass (37.5% vs 5.2%, P=0.02). One patient with PTSAH and associated mass effect deteriorated clinically.

CONCLUSIONS

An increased number of stent retriever passes, distal device positioning, and presence of severe vasospasm were associated with PTSAH. Neurological deterioration with PTSAH can occur.

Nontraumatic, posterior circulation pseudoaneurysm of the basilar artery summit with complete spontaneous resolution: Case report and literature review

Background:

Intracranial pseudoaneurysms are rare vascular defects of arterial walls that are classically the result of traumatic injury, iatrogenic causes, or infection. Idiopathic pseudoaneurysms are seen even less frequently and are often related to atherosclerosis. Pseudoaneurysms are most commonly found along the distal wall of the internal carotid artery, however, can occur at any location in the cerebrovascular circulation. Treatment of these arterial defects is often challenging due to their frail nature.

Case Description:

A 61-year-old male with a history of hypertension presented with a severe, atypical headache without history of trauma. Computed tomography (CT) and computed tomography angiography (CTA) demonstrated diffuse subarachnoid hemorrhage. Imaging demonstrated a 3.5 mm pseudoaneurysm projecting distally from the basilar artery at the apex. Repeated imaging (CTA, digital subtraction angiography) demonstrated decreased size and flow associated within the aneurysm over the following 2 weeks; as such, the patient was managed conservatively. The patient was discharged in neurologically intact condition when imaging at 14 days confirmed complete and spontaneous resolution of the pseudoaneurysm.

Conclusion:

Idiopathic pseudoaneurysms that are commonly associated with atherosclerosis are most commonly managed surgically or endovascularly. Conservative approach may be considered in a select group of patients that exhibit decreased size and/or flow within the aneurysm in repeated imaging; spontaneous resolution was seen in the present case.

Current Research and Opportunities to Address Environmental Asbestos Exposures

Asbestos-related diseases continue to result in approximately 120,000 deaths every year in the United States and worldwide. Although extensive research has been conducted on health effects of occupational exposures to asbestos, many issues related to environmental asbestos exposures remain unresolved. For example, environmental asbestos exposures associated with a former mine in Libby, Montana, have resulted in high rates of nonoccupational asbestos-related disease. Additionally, other areas with naturally occurring asbestos deposits near communities in the United States and overseas are undergoing investigations to assess exposures and potential health risks. Some of the latest public health, epidemiological, and basic research findings were presented at a workshop on asbestos at the 2014 annual meeting of the Society of Toxicology in Phoenix, Arizona. The following focus areas were discussed: a) mechanisms resulting in fibrosis and/or tumor development; b) relative toxicity of different forms of asbestos and other hazardous elongated mineral particles (EMPs); c) proper dose metrics (e.g., mass, fiber number, or surface area of fibers) when interpreting asbestos toxicity; d) asbestos exposure to susceptible populations; and e) using toxicological findings for risk assessment and remediation efforts. The workshop also featured asbestos research supported by the National Institute of Environmental Health Sciences, the Agency for Toxic Substances and Disease Registry, and the U.S. Environmental Protection Agency. Better protection of individuals from asbestos-related health effects will require stimulation of new multidisciplinary research to further our understanding of what constitutes hazardous exposures and risk factors associated with toxicity of asbestos and other hazardous EMPs (e.g., nanomaterials).

Considerations Before Establishing an Environmental Health Registry

Public health registries can provide valuable information when health consequences of environmental exposures are uncertain or will likely take long to develop. They can also aid research on diseases that may have environmental causes that are not completely well defined. We discuss factors to consider when deciding whether to create an environmental health registry. Those factors include public health significance, purpose and outcomes, duration and scope of data collection and availability of alternative data sources, timeliness, availability of funding and administrative capabilities, and whether the establishment of a registry can adequately address specific health concerns. We also discuss difficulties, limitations, and benefits of exposure and disease registries, based on the experience of the Agency for Toxic Substances and Disease Registry.

Mortality study of civilian employees exposed to contaminated drinking water at USMC Base Camp Lejeune: a retrospective cohort study

BACKGROUND

Two drinking water systems at U.S. Marine Corps Base Camp Lejeune, North Carolina were contaminated with solvents during 1950s-1985.

METHODS

We conducted a retrospective cohort mortality study of 4,647 civilian, full-time workers employed at Camp Lejeune during 1973-1985 and potentially exposed to contaminated drinking water. We selected a comparison cohort of 4,690 Camp Pendleton workers employed during 1973-1985 and unexposed to contaminated drinking water. Mortality follow-up period was 1979-2008. Cause-specific standardized mortality ratios utilized U.S. age-, sex-, race-, and calendar period-specific mortality rates as reference. We used survival analysis to compare mortality rates between Camp Lejeune and Camp Pendleton workers and assess the effects of estimated cumulative contaminant exposures within the Camp Lejeune cohort. Ground water contaminant fate/transport and distribution system models provided monthly estimated contaminant levels in drinking water serving workplaces at Camp Lejeune. The confidence interval (CI) indicated precision of effect estimates.

RESULTS

Compared to Camp Pendleton, Camp Lejeune workers had mortality hazard ratios (HRs) >1.50 for kidney cancer (HR = 1.92, 95% CI: 0.58, 6.34), leukemias (HR = 1.59, 95% CI: 0.66, 3.84), multiple myeloma (HR = 1.84, 95% CI: 0.45, 7.58), rectal cancer (HR = 1.65, 95% CI: 0.36, 7.44), oral cavity cancers (HR = 1.93, 95% CI: 0.34, 10.81), and Parkinson's disease (HR = 3.13, 95% CI: 0.76, 12.81). Within the Camp Lejeune cohort, monotonic exposure-response relationships were observed for leukemia and vinyl chloride and PCE, with mortality HRs at the high exposure category of 1.72 (95% CI: 0.33, 8.83) and 1.82 (95% CI: 0.36, 9.32), respectively. Cumulative exposures were above the median for most deaths from cancers of the kidney, esophagus, rectum, prostate, and Parkinson's disease, but small numbers precluded evaluation of exposure-response relationships.

CONCLUSION

The study found elevated HRs in the Camp Lejeune cohort for several causes of death including cancers of the kidney, rectum, oral cavity, leukemias, multiple myeloma, and Parkinson's disease. Only 14% of the Camp Lejeune cohort died by end of follow-up, producing small numbers of cause-specific deaths and wide CIs. Additional follow-up would be necessary to comprehensively assess drinking water exposure effects at the base.

Evaluation of mortality among marines and navy personnel exposed to contaminated drinking water at USMC base Camp Lejeune: a retrospective cohort study

BACKGROUND

Two drinking water systems at U.S. Marine Corps Base Camp Lejeune, North Carolina were contaminated with solvents during 1950s-1985.

METHODS

We conducted a retrospective cohort mortality study of Marine and Naval personnel who began service during 1975-1985 and were stationed at Camp Lejeune or Camp Pendleton, California during this period. Camp Pendleton's drinking water was uncontaminated. Mortality follow-up was 1979-2008. Standardized Mortality Ratios were calculated using U.S. mortality rates as reference. We used survival analysis to compare mortality rates between Camp Lejeune (N = 154,932) and Camp Pendleton (N = 154,969) cohorts and assess effects of cumulative exposures to contaminants within the Camp Lejeune cohort. Models estimated monthly contaminant levels at residences. Confidence intervals (CIs) indicated precision of effect estimates.

RESULTS

There were 8,964 and 9,365 deaths respectively, in the Camp Lejeune and Camp Pendleton cohorts. Compared to Camp Pendleton, Camp Lejeune had elevated mortality hazard ratios (HRs) for all cancers (HR = 1.10, 95% CI: 1.00, 1.20), kidney cancer (HR = 1.35, 95% CI: 0.84, 2.16), liver cancer (HR = 1.42, 95% CI: 0.92, 2.20), esophageal cancer (HR = 1.43 95% CI: 0.85, 2.38), cervical cancer (HR = 1.33, 95% CI: 0.24, 7.32), Hodgkin lymphoma (HR = 1.47, 95% CI: 0.71, 3.06), and multiple myeloma (HR = 1.68, 95% CI: 0.76, 3.72). Within the Camp Lejeune cohort, monotonic categorical cumulative exposure trends were observed for kidney cancer and total contaminants (HR, high cumulative exposure = 1.54, 95% CI: 0.63, 3.75; log10 β = 0.06, 95% CI: -0.05, 0.17), Hodgkin lymphoma and trichloroethylene (HR, high cumulative exposure = 1.97, 95% CI: 0.55, 7.03; β = 0.00005, 95% CI: -0.00003, 0.00013) and benzene (HR, high cumulative exposure = 1.94, 95% CI: 0.54, 6.95; β = 0.00203, 95% CI: -0.00339, 0.00745). Amyotrophic Lateral Sclerosis (ALS) had HR = 2.21 (95% CI: 0.71, 6.86) at high cumulative vinyl chloride exposure but a non-monotonic exposure-response relationship (β = 0.0011, 95% CI: 0.0002, 0.0020).

CONCLUSION

The study found elevated HRs at Camp Lejeune for several causes of death including cancers of the kidney, liver, esophagus, cervix, multiple myeloma, Hodgkin lymphoma and ALS. CIs were wide for most HRs. Because <6% of the cohort had died, long-term follow-up would be necessary to comprehensively assess effects of drinking water exposures at the base.

Impact of body mass index on the detection of radiographic localized pleural thickening

RATIONALE AND OBJECTIVES

Subpleural fat can be difficult to distinguish from localized pleural thickening (LPT), a marker of asbestos exposure, on chest radiographs. The aims of this study were to examine the influence of body mass index (BMI) on the performance of radiograph readers when classifying LPT and to model the risk of false test results with varying BMI.

MATERIALS AND METHODS

Subjects (n = 200) were patients being screened or treated for asbestos-related health outcomes. A film chest radiograph, a digital chest radiograph, and a high-resolution computed tomography (HRCT) chest scan were collected from each subject. All radiographs were independently read by seven B readers and scored using the International Labour Office system. HRCT scans, read by three experienced thoracic radiologists, served as the gold standard for the presence of LPT. We calculated measures of radiograph reader performance, including sensitivity and specificity, for each image modality. We also used logistic regression to estimate the probability of a false-positive and a false-negative result while controlling for covariates.

RESULTS

The proportion of false-positive readings correlated with BMI. While controlling for covariates, regression modeling showed the probability of a false-positive result increased with increasing BMI category, younger age, not having pleural calcification, and among subjects not reporting occupational or household contact asbestos exposure.

CONCLUSIONS

Clinicians should be cautious when evaluating radiographs of younger obese persons for the presence of asbestos-related pleural plaque, particularly in populations having an anticipated low or background prevalence of LPT.

Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008

BACKGROUND

The decline in asbestos use in the United States may impact mesothelioma incidence.

OBJECTIVE

This report provides national and state-specific estimates of mesothelioma incidence in the United States using cancer surveillance data for the entire US population.

METHODS

Data from the National Program for Cancer Registries and the Surveillance, Epidemiology, and End Results program were used to calculate incidence rates and annual percent change.

RESULTS

During 2003-2008, an average of 1.05 mesothelioma cases per 100 000 persons were diagnosed annually in the United States; the number of cases diagnosed each year remained level, whereas rates decreased among men and were stable among women.

CONCLUSION

US population-based cancer registry data can be used to determine the burden of mesothelioma and track its decline. Even 30 years after peak asbestos use in the United States, 3200 mesothelioma cases are diagnosed annually, showing that the US population is still at risk.

Associations between radiographic findings and spirometry in a community exposed to Libby amphibole

BACKGROUND

Among asbestos-exposed individuals, abnormal spirometry is usually associated with parenchymal abnormalities or diffuse pleural thickening. Localised pleural thickening (LPT), the most common abnormality associated with asbestos exposure, is typically thought to be a marker of exposure with little clinical consequence. Our objective was to determine if abnormal spirometry is associated with LPT independent of other abnormalities, using data from community-based screening conducted in Libby, Montana.

METHODS

Subjects were a subset of screening participants comprising persons with interpretable spirometry and chest radiograph results (n=6475). Chest radiographs were independently evaluated by two or three B readers, and participants were classified by mutually exclusive categories of spirometry outcome: normal, restriction, obstruction or mixed defect.

RESULTS

Restrictive spirometry was strongly associated with parenchymal abnormalities (OR 2.9; 95% CI 1.4 to 6.0) and diffuse pleural thickening (OR 4.1; 95% CI 2.1 to 7.8). Controlling for the presence of these abnormalities as well as age, smoking status and other covariates, restrictive spirometry was also associated with LPT (OR 1.4; 95% CI 1.1 to 1.8). The risk of restrictive spirometric findings correlated with the severity of LPT.

CONCLUSIONS

In this large community-based screening cohort, restrictive spirometry is significantly associated with LPT, indicating that this abnormality may result in lung function impairment. Physicians treating patients exposed to Libby amphibole should be aware that LPT may have functional consequences.

Exposure to asbestos-containing vermiculite ore and respiratory symptoms among individuals who were children while the mine was active in Libby, Montana

BACKGROUND

Libby, Montana, was home to the largest vermiculite ore mine in the United States. The processing, use, and transport of the ore, which was contaminated with amphibole asbestos, led to generalized contamination of the community. The mine closed in 1990.

OBJECTIVES

We examined the prevalence of respiratory symptoms in 2000-2001 and their association with history of vermiculite exposure among people who were < or = 18 years of age when the mine closed.

METHODS

Information on respiratory symptoms and exposure history was collected by questionnaire in 2000-2001, at which time participants were 10-29 years old. Logistic regression was used to model the associations between exposures and outcomes adjusted for age, sex, and tobacco smoke exposure.

RESULTS

Of the 1,003 individuals included in the study, 10.8% reported usually having a cough, 14.5% reported experiencing shortness of breath when walking up a slight hill or hurrying on level ground, and 5.9% reported having coughed up bloody phlegm in the past year. These respiratory symptoms were positively associated with frequently handling vermiculite insulation compared with never handling vermiculite insulation. We found no association between vermiculite insulation in the house and respiratory symptoms. Respiratory symptoms were associated with other vermiculite exposures as well, and the number and frequency of these activities showed a positive trend with usually having a cough. We found no association between any of the activities and abnormal spirometry.

CONCLUSIONS

These data suggest that residents of Libby, Montana, who were children when the mine closed experienced some respiratory symptoms associated with asbestos-contaminated vermiculite exposure.

Nested case-control study of autoimmune disease in an asbestos-exposed population

OBJECTIVE

To explore the potential association between asbestos exposure and risk of autoimmune disease, we conducted a case-control study among a cohort of 7,307 current and former residents of Libby, Montana, a community with historical occupational and environmental exposure to asbestos-contaminated vermiculite.

METHODS

Cases were defined as those who reported having one of three systemic autoimmune diseases (SAIDs): systemic lupus erythematosus, scleroderma, or rheumatoid arthritis (RA). Controls were randomly selected at a 3:1 ratio from among the remaining 6,813 screening participants using frequency-matched age and sex groupings.

RESULTS

The odds ratios (ORs) and 95% confidence intervals (CIs) for SAIDs among those >or=65 years of age who had worked for the vermiculite mining company were 2.14 (95% CI, 0.90-5.10) for all SAIDs and 3.23 (95% CI, 1.31-7.96) for RA. In this age group, exposure to asbestos while in the military was also an independent risk factor, resulting in a tripling in risk. Other measures of occupational exposure to vermiculite indicated 54% and 65% increased risk for SAIDs and RA, respectively. Those who had reported frequent contact with vermiculite through various exposure pathways also demonstrated elevated risk for SAIDs and RA. We found increasing risk estimates for SAIDs with increasing numbers of reported vermiculite exposure pathways (p<0.001).

CONCLUSION

These preliminary findings support the hypothesis that asbestos exposure is associated with autoimmune disease. Refined measurements of asbestos exposure and SAID status among this cohort will help to further clarify the relationship between these variables.

Blindness associated with enlarging mycotic aneurysm after cavernous sinus thrombosis

PURPOSE

We report a patient with an enlarging internal carotid mycotic aneurysm secondary to septic cavernous sinus thrombosis presenting with acute visual loss.

DESIGN

Single observational case report.

METHODS

Retrospective review of the medical record and review of the literature.

RESULTS

A 19-year-old man with residual left sixth nerve palsy and decreased vision in his left eye caused by left cavernous sinus thrombosis secondary to pansinusitis was seen 2 weeks after discharge with acute decreased visual acuity in the right eye. A workup revealed an enlarging left carotid/ophthalmic aneurysm that compressed the optic chiasm and right optic nerve. The patient was taken to the interventional angiography suite, where his left internal carotid artery was occluded endovascularly. The patient's vision improved on discharge.

CONCLUSIONS

Visual loss caused by a mycotic carotid aneurysm is an infrequent sequelae after cavernous sinus thrombosis and is not well described in the literature. To our knowledge, this is the first reported case of acute visual loss associated with a mycotic ophthalmic aneurysm. The result of treatment was good in this case, with the patient's visual acuity returning to pretreatment status.

Vertebroplasty in focal Paget disease of the spine. Case report

Paget disease is an idiopathic metabolic disease of bone that may involve the axial and appendicular skeleton. In up to one third of patients there may be pagetoid involvement of the spine, which can cause back pain and vertebral collapse, with instability or myeloradiculopathy. Although medical therapy is the mainstay of treatment, decompressive surgery or stabilization may be required. The authors report on a case of localized Paget disease of the spine treated successfully by performing percutaneous vertebroplasty. They propose this procedure as a useful intervention that can be undertaken safely in patients with spinal Paget disease, in whom acquisition of a transpedicular biopsy sample is required as part of diagnosis.

Bilateral aberrant internal carotid arteries with bilateral persistent stapedial arteries and bilateral duplicated internal carotid arteries

A 5-year-old boy was evaluated for a left retrotympanic mass found at otoscopy. Subsequent petrous bone CT and MR angiographic examinations demonstrated bilateral aberrant internal carotid, bilateral stapedial artery persistence, and bilateral duplicated internal carotid arteries. Imaging findings and their clinical relevance are discussed. A second case of unilateral aberrant internal carotid artery with a persistent stapedial artery is included for comparison.

Cerebral angiographic findings of spontaneous intracranial hypotension

We report a case of spontaneous intracranial hypotension that underwent cerebral angiography. The angiogram showed prominence of the veins and venous phase of the angiogram. This is thought to be secondary to decreased intracranial pressure and subsequent dilation of the venous system to attempt to replace the lost intracranial CSF volume. In situations in which the typical clinical presentation is not present and additional examinations such as cerebral angiography are performed, these findings may be helpful to direct the physicians involved toward the correct diagnosis.

Imaging of the glossopharyngeal, vagus, and accessory nerves

The origination and course of the glossopharyngeal, vagus and accessory cranial nerves explains their function and localizes pathology. Abnormalities of these lower cranial nerves may be intrinsic or extrinsic and is due to a multiplicity of disease processes. The clinical presentation of the involved cranial nerve helps to guide imaging evaluation. Magnetic resonance imaging without and with contrast is the mainstay of imaging of cranial nerves IX, X and XI pathology, but computed tomography provides substantial information as well.

December 2000: 6 month old boy with 2 week history of progressive lethargy

This 6-month-old Caucasian boy presented with a 10-day history of lethargy, obtundation, inability to hold his head up and mild torticollis. MRI and CT scans showed a large solid and cystic mass involving the right temporal, parietal and occipital lobes, pineal, superior pons, mesencephalon and posterior right thalamus. He underwent craniotomy initially for a partial tumor resection with an intraoperative diagnosis of desmoplastic astrocytoma. With immunohistochemistry and special stains the diagnosis of desmoplastic infantile ganglioglioma (DIG) was made. A near total resection was performed a week after initial resection.The patient then was treated with chemotherapy. Two months later an MRI showed tumor growth. Following additional aggressive chemotherapy, an MRI at 5 months post-resection indicated further tumor progression. This case illustrates that some DIGs may behave more aggressively than typical WHO grade I lesions.

Gadolinium-enhanced magnetic resonance imaging in Bell's palsy

Inflammation of the facial nerve in Bell's palsy can be demonstrated on gadolinium-enhanced magnetic resonance imaging. We have studied a series of 17 Bell's palsy patients with gadolinium-enhanced magnetic resonance imaging, and the purpose of this paper is to report our findings and discuss their significance. Most acute Bell's palsy cases demonstrate facial nerve enhancement, usually in the distal internal auditory canal and labyrinthine/geniculate segments. Other segments demonstrate enhancement less often. Gadolinium enhancement occurs regardless of the severity of the paralysis and can persist after clinical improvement of the paralysis. The findings of this study corroborate other evidence that the segments of the facial nerve most often involved in Bell's palsy are the only segments that are most often enhanced with gadolinium-enhanced magnetic resonance imaging. The role of gadolinium-enhanced magnetic resonance imaging in the management of Bell's palsy patients is discussed.

Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance

Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.

Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance

Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel's patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.

Falx ossification--MR visualization

While falx calcification is rarely demonstrated using magnetic resonance, falx ossification, when seen, is characteristic. On magnetic resonance images, falx ossification exhibits a typical appearance consisting of a central marrow-containing portion with signal intensity similar to fat, surrounded by low signal intensity representing cortical bone. Falx ossification was seen in 0.7% of patients and should not be confused with a falx lipoma, a rare congenital entity.

Imaging of cranial chordomas

The clinical, pathologic, and imaging characteristics of clival chordomas in 14 patients who underwent magnetic resonance examinations were evaluated. Magnetic resonance imaging (MRI) was compared with skull series, tomography, computed tomography (CT), and magnification angiography in the diagnosis of clival chordomas. Although all examinations were highly sensitive for the detection of clival chordomas, MRI was the best single study because of its ability to image in orthogonal planes, its excellent soft-tissue contrast, and its demonstration of the relationship between the neoplasm and regional vital structures, particularly the brainstem, cavernous sinus, cranial nerves, and neighboring vessels. The deficiencies of MRI are poor visualization of tumoral calcification and osseous destruction--findings that are better identified on CT. In all 14 cases, MRI revealed the neoplasms to be black on inversion-recovery, gray on partial-saturation, and white on T2-weighted pulse sequences. Three chordomas had a speckled signal void pattern, typical of tumor calcification.

Glomus tympanicum chemodectomas: radiographic and clinical characteristics

Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.

Primary spinal melanoma

The records of five patients with primary melanoma of the spinal cord were reviewed. The tumor most frequently presented as an intramedullary middle or lower thoracic cord lesion. The average duration of symptoms before pathological diagnosis was 29 months, and the average survival after laminectomy and radiation therapy was 6 years 7 months. The findings in this series, when compared with those in the literature, suggest that primary spinal melanoma is a more indolent malignancy than previously reported or than melanoma metastatic to the central nervous system.

Computer-assisted scheduling of radiology resident call

The difficulties inherent in assigning an entire residency group fair and equivalent daily call prompted the development of a computerized scheduling program at The University of Texas at Houston. Written in COBOL, the program is run on a CDC mainframe computer. Logic parameters restrict the number and frequency of calls per month, and each resident is coded for five available call types at two university hospitals. The foundation of the program's operation is an arbitrary point scale applied to each call type determined by its difficulty and time commitment. Residents' point totals each month are roughly balanced within a prescribed range, with call exchanges made by the computer if necessary. The computer-generated schedules are flexible and equitable, require little manual correction, and save time for the chief resident and the residency secretary.

Complications of colonic interposition

The roentgenographic and surgical experience with 44 patients treated with colon interpositions was examined. Forty-two of these patients had carcinoma of the esophagus. Staged therapy consisted of mediastinal irradiation, colonic interposition, and total esophagectomy. The more common complications related to luminal patency and conduit integrity. A total of 29.5% developed anastomotic narrowing due to postoperative edema. Anastomotic leaks arose only at the proximal anastomosis and had an incidence rate of 31.8%. Thirty-four percent had fistulous tracts originating in the reconstructed upper gastrointestinal tract. In eighty percent of the patients with leaks or fistulae, their defects healed spontaneously or with simple drainage. Strictures were encountered in 59.1%, and there were 5 instances of colonic graft ischemia. The mortality directly related to surgery was 6.8%. Ischemia, particularly at the cervical anastomosis, is probably the most common cause of complications. Radiographic evaluation is recommended using a single contrast barium examination unless gross extravasation is expected.