Magnetic resonance neurography in the diagnosis of neuropathies of the lumbosacral plexus: a pictorial review.

Magnetic resonance neurography (MRN) is an important tool to detect abnormalities of peripheral nerves. This pictorial review demonstrates the MRN features of a variety of neuropathies affecting the lumbosacral plexus (LSP) and lower extremity nerves, drawn from over 1200 MRNs from our institution and supplemented by the literature. Abnormalities can be due to spinal compression, extraspinal compression, malignancy, musculoskeletal disease, iatrogenesis, inflammation, infection, and idiopathic disorders. We discuss indications and limitations of MRN in diagnosing LSP neuropathies. As MRN becomes more widely used, physicians must become familiar with the differential diagnosis of abnormalities detectable with MRN of the LSP.

Prevalence and significance of incidentally noted dilation of the ascending aorta on routine chest computed tomography in older patients.

OBJECTIVE: The aim of this study was to determine the prevalence of incidental ascending aortic dilation and its significance over time in 55- to 80-year-olds undergoing routine computed tomographic scans. METHODS: Chest computed tomography reports for 64,092 patients who met the inclusion criteria were used to determine the prevalence of incidental ascending aortic dilation (4-5 cm) and, when possible, aortic growth rates. A chart review was performed to identify any aortic complication or intervention. RESULTS: The prevalence of incidental aortic dilation was 2.7% (671/24,992 patients). Of the 327 patients with aortic dilation and follow-up studies (mean, 3.4 years), only 3.7% (n = 12) demonstrated interval growth (mean of 0.9 mm/y). No patient underwent prophylactic surgery or intervention on the basis of aortic size or growth rate. One patient developed a type A dissection. CONCLUSIONS: Current guidelines for yearly surveillance imaging of aortic dilation could be revised to increase the follow-up interval and/or improve risk stratification to better identify the small subset of patients most likely to have disease progression.

Perspectives from deductible plan enrollees: plan knowledge and anticipated care-seeking changes.

BACKGROUND: Consumer directed health care proposes that patients will engage as informed consumers of health care services by sharing in more of their medical costs, often through deductibles. We examined knowledge of deductible plan details among new enrollees, as well as anticipated care-seeking changes in response to the deductible. METHODS: In a large integrated delivery system with a range of deductible-based health plans which varied in services included or exempted from deductible, we conducted a mixed-method, cross-sectional telephone interview study. RESULTS: Among 458 adults newly enrolled in a deductible plan (71% response rate), 51% knew they had a deductible, 26% knew the deductible amount, and 6% knew which medical services were included or exempted from their deductible. After adjusting for respondent characteristics, those with more deductible-applicable services and those with lower self-reported health status were significantly more likely to know they had a deductible. Among those who knew of their deductible, half anticipated that it would cause them to delay or avoid medical care, including avoiding doctor's office visits and medical tests, even services that they believed were medically necessary. Many expressed concern about their costs, anticipating the inability to afford care and expressing the desire to change plans. CONCLUSION: Early in their experience with a deductible, patients had limited awareness of the deductible and little knowledge of the details. Many who knew of the deductible reported that it would cause them to delay or avoid seeking care and were concerned about their healthcare costs.

Imaging and diagnosis of postpartum complications: sonography and other imaging modalities.

Postpartum complications can be broadly divided into 4 categories: postpartum hemorrhage, obstetrical trauma, thromboembolic complications, and puerperal infections. Postpartum hemorrhage is most commonly caused by uterine atony, abnormal placentation, or genital tract trauma. Secondary causes of hemorrhage include retained products of conception and, rarely, subinvolution of the placental implantation site. Uterine dehiscence or rupture may be occult on ultrasound examination and may be better visualized on sagittal computed tomography or magnetic resonance imaging. Obstetric trauma during prolonged vaginal or cesarean delivery may lead to fistula formation, ureteral injury, or bowel injury. Later potential complications of cesarean delivery include cesarean delivery scar ectopic, endometrial implants in the cesarean scar, and placenta accreta. Thromboembolic complications can include pulmonary embolism and deep vein thrombosis as well as ovarian vein thrombosis, the latter of which can be difficult to clinically differentiate from appendicitis in the postpartum female.

Delayed enhancement of ascites after i.v. contrast material administration at CT: time course and clinical correlation.

OBJECTIVE: The objective of our study was to determine the prevalence and clinical predictors of delayed contrast enhancement of ascites. MATERIALS AND METHODS: In this retrospective study, 132 consecutive patients with ascites who underwent repeated abdominopelvic CT examinations performed within 7 days of each other were identified. These patients included 112 patients who received and 20 who did not receive i.v. contrast material at the initial CT examination. For each examination, we recorded the CT attenuation of the ascites. For the follow-up scan, the presence of delayed enhancement of ascites was defined as an increase in CT attenuation > 10 HU over baseline. The Fisher's exact test, unpaired Student's t test, and logistic regression were used to determine predictors of delayed enhancement of ascites. RESULTS: A threshold increase in the attenuation of ascites by > 10 HU or more between the initial and follow-up CT examinations occurred only when i.v. contrast material was given with the initial examination. The increased attenuation was due to delayed contrast enhancement of ascites and occurred in 15 of the 112 patients (13%). Of the 16 patients scanned less than 1 day apart, 10 (63%) showed delayed enhancement of ascites. Delayed enhancement was not observed 3 or more days after i.v. contrast material administration. For each 1 mg/dL increase in serum creatinine level, the likelihood of delayed enhancement of ascites increased (odds ratio, 2.02; 95% CI, 1.11-3.69). Multivariate logistic regression showed that a short time interval between examinations (p < 0.001), increased serum creatinine level (p < 0.001), and presence of loculated ascites (p = < 0.01) were independent predictors of the magnitude of delayed enhancement of ascites. CONCLUSION: Delayed contrast enhancement of ascites occurs commonly after recent prior i.v. contrast material administration and should not be mistaken for hemoperitoneum or proteinaceous fluid such as pus.

High-deductible health insurance plans: efforts to sharpen a blunt instrument.

High deductible-based health insurance plans require consumers to pay for care until reaching the deductible amount. However, information is limited on how well consumers understand their benefits and how they respond to these costs. In telephone interviews, we found that consumers had limited knowledge about their deductibles yet frequently reported changing their care-seeking behavior because of the cost. Poor knowledge limited the effects of the deductible design, with some consumers avoiding care for services that were exempt from the deductible. Consumers need more information and decision support to understand their benefits and to differentiate when care is necessary, discretionary, or unnecessary.

Imaging of hepatic infections.

Hepatic infections include pyogenic and amebic abscesses and fungal and parasitic diseases. Entry of the infectious organisms into the liver can occur by hematogenous spread via the portal vein or hepatic artery, ascension of the infection from the biliary tract, or from trauma. Worldwide, liver abscess is most often caused by Entamoeba histolytica, but in the developed world, pyogenic liver abscess is more common. Fungal infection is most often seen in immunosuppressed chemotherapy patients, whereas parasitic infections are seen in patients with recent travel to endemic areas of Asia, Africa, and South America. Imaging, and in particular ultrasound, plays a crucial role in following patients from treatment to resolution of disease.We review the ultrasound and computed tomographic findings and the clinical features that are characteristic of hepatic pyogenic abscess, amebic abscess, fungal infection, and parasitic infection.

Influence of patient costs and requests on emergency physician decisionmaking.

STUDY OBJECTIVES: We examine emergency physician knowledge of, attitudes about, and responses to patient cost-sharing in the emergency department (ED). METHODS: A convenience sample of emergency physicians from an integrated delivery system completed a questionnaire including self-report questions about knowledge of and attitudes about cost-sharing and an experimental vignette. The vignette describes a patient with an uncomplicated asthma exacerbation, with a version in which she has a $100 ED visit copayment and a version in which she does not. Subjects responded with their "best judgment" of whether they would order a chest radiograph and their decision after specific patient request. We examined the frequency of responses overall and associated characteristics with chi(2) testing. RESULTS: Of 204 respondents (349 eligible participants [58%]), 203 answered the vignette questions. No respondent reported that ordering a radiograph was clinically appropriate; however, 85% reported that they would order a radiograph if the patient requested it. There were no significant differences in the percentage of physicians ordering the test across the 2 versions. Overall, 77% of respondents reported having limited awareness of an individual patient's cost-sharing level; 67% reported that patient costs sometimes affect their clinical decisions; only 10% estimated changing their decisions in greater than 20% of encounters in which the cost-sharing level was known. CONCLUSION: Emergency physicians are usually not aware of a patient's cost-sharing level and, in instances which they are, report that this knowledge rarely affects their clinical decisions. However, emergency physicians are responsive to patient requests, even when the treatment request differs from their clinical judgment.

Office visit copayments: patient knowledge, response, and communication with providers.

BACKGROUND: There is limited information on patients' knowledge about their cost-sharing requirements and how that influenced their care-seeking behavior. OBJECTIVE: To examine patients' knowledge of their office visit copayments, their self-reported responses to perceived and actual copayments, and discussions with physicians about costs. RESEARCH DESIGN: Cross-sectional telephone interview study with a 71% response rate. SUBJECTS: Stratified random sample of 479 adult members of a prepaid, integrated delivery system: equal sample of members with and without a chronic disease. MEASURES: Perceived and actual office visit copayment amounts, patient self-reported behavioral responses to copayments, cost discussions with a physician, and patient attitudes about discussing costs. RESULTS: Overall, 50% of respondents correctly reported their copayment amount, with 39% underestimating and 11% overestimating. Among respondents who reported having copayments, 27% reported delaying or avoiding a visit altogether, or talking to a physician/advice nurse instead of attending an in-person visit because of their copayment. Perceived office visit copayment amounts were significantly associated with self-reported behavior changes (OR, 1.47 per $10; 95% CI, 1.06-2.05). Only 4% of respondents reported talking with their physician about their costs, with 79% believing that their providers cannot help them with their costs, and 51% believing that it is inappropriate to discuss costs with their physician. CONCLUSIONS: Patients have limited knowledge of their office visit copayment amounts, and are changing their care-seeking behavior in response to perceived costs. Moreover, most patients are making these changes without discussing their cost concerns with their physician.

A neutralizing anti-Nogo66 receptor monoclonal antibody reverses inhibition of neurite outgrowth by central nervous system myelin.

The Nogo66 receptor (NgR1) is a neuronal, leucine-rich repeat (LRR) protein that binds three central nervous system (CNS) myelin proteins, Nogo, myelin-associated glycoprotein, and oligodendrocyte myelin glycoprotein, and mediates their inhibitory effects on neurite growth. Although the LRR domains on NgR1 are necessary for binding to the myelin proteins, the exact epitope(s) involved in ligand binding is unclear. Here we report the generation and detailed characterization of an anti-NgR1 monoclonal antibody, 7E11. The 7E11 monoclonal antibody blocks Nogo, myelin-associated glycoprotein, and oligodendrocyte myelin glycoprotein binding to NgR1 with IC50 values of 120, 14, and 4.5 nm, respectively, and effectively promotes neurite outgrowth of P3 rat dorsal root ganglia neurons cultured on a CNS myelin substrate. Further, we have defined the molecular epitope of 7E11 to be DNAQLR located in the third LRR domain of rat NgR1. Our data demonstrate that anti-NgR1 antibodies recognizing this epitope, such as 7E11, can neutralize CNS myelin-dependent inhibition of neurite outgrowth. Thus, specific anti-NgR1 antibodies may represent a useful therapeutic approach for promoting CNS repair after injury.

Alpha 7 nicotinic acetylcholine receptors mediate beta-amyloid peptide-induced tau protein phosphorylation.

The Alzheimer's disease pathogenic peptide, beta-amyloid42 (A beta 42), induces tau protein phosphorylation. Because hyperphosphorylated tau is a consistent component of neurofibrillary tangles, a pathological hallmark of Alzheimer's disease, we investigated the signaling molecules involved in A beta 42-induced tau phosphorylation. We show that A beta 42 elicited rapid and reversible tau protein phosphorylation on three proline-directed sites (Ser-202, Thr-181, and Thr-231) in systems enriched in alpha 7 nicotinic acetylcholine receptors (alpha 7nAChR) including serum-deprived human SK-N-MC neuroblastoma cells and hippocampal synaptosomes. Although alpha 7nAChR agonists induced similar phosphorylation, pretreatment with antisense-alpha 7nAChR oligonucleotides (in cells) or alpha 7nAChR antagonists (in cells and synaptosomes) attenuated A beta-induced tau phosphorylation. Western analyses showed that the mitogen-activated kinase cascade proteins, ERKs and c-Jun N-terminal kinase (JNK-1), were concomitantly activated by A beta 42, and their respective kinase inhibitors suppressed A beta-induced tau phosphorylation. More importantly, recombinant-activated ERKs and JNK-1 could differentially phosphorylate tau protein in vitro. Thus, the alpha 7nAChR may mediate A beta-induced tau protein phosphorylation via ERKs and JNK-1.