Diagnostic Performance of Routine Brain MRI Sequences for Dural Venous Sinus Thrombosis

BACKGROUND AND PURPOSE:Signs suggestive of unexpected dural venous sinus thrombosis are detectable on routine MR imaging studies without MRV. We assessed performance characteristics and interrater reliability of routine MR imaging for the diagnosis of dural venous sinus thrombosis, focusing on the superior sagittal, transverse, and sigmoid sinuses.MATERIALS AND METHODS:This case series included 350 patients with MRIs performed with contrast-enhanced MRV and 79 patients with routine MRIs performed within 48 hours of a CTV from 2008 to 2014 (total, n = 429). Routine MR images were separated from the contrast-enhanced MRVs and CTVs. Three neuroradiologists, blinded to clinical data, independently reviewed the MRIs for signs of dural venous sinus thrombosis, including high signal on sagittal T1, loss of flow void on axial T2, high signal on FLAIR, high signal on DWI, increased susceptibility effects on T2*-weighted gradient recalled-echo imaging, and filling defects on axial contrast-enhanced spin-echo T1WI and/or volumetric gradient-echo T1WI. Two neuroradiologists independently reviewed contrast-enhanced MRVs and CTVs to determine the consensus gold standard. Interrater reliability was calculated by using the κ coefficient.RESULTS:Contrast-enhanced MRV and CTV confirmed that dural venous sinus thrombosis was present in 72 of 429 cases (16.8%). The combination of routine MR sequences had an overall sensitivity of 79.2%, specificity of 89.9%, and moderate interrater reliability (κ = 0.50). The 3 readers did not have similar performance characteristics. 69.4% of positive cases had clinical suspicion of dural venous sinus thrombosis indicated on imaging requisition.CONCLUSIONS:Routine MR images can suggest dural venous sinus thrombosis with high specificity in high-risk patients, even in cases without clinical suspicion.

Dural venous sinus thrombosis (DVST) is a condition that ranges from being undiagnosed to leading to serious morbidity and mortality, including venous infarction and intracranial hemorrhage.¹ DVST has a highly variable clinical presentation, from asymptomatic to acute or subacute headaches, signs or symptoms of increased intracranial pressure, focal neurologic deficits, or seizures.^2,3 The diagnosis is important to consider even in younger patients, with risk factors such as genetic and acquired prothrombotic states, trauma, and infections or inflammatory conditions.^1,2Although early and accurate diagnosis is important for initiation of treatment and prevention of serious complications, the median diagnostic delay from symptom onset is 7 days.^1–4 When DVST is suspected, the current criterion standard for diagnosis is either contrast-enhanced MRV (CEMRV) or CTV.⁵ However, the imaging signs of unexpected DVST are seen during interpretation of routine MR imaging studies performed without dedicated CEMRV, concurrent CTV, or relevant clinical history. Typical findings might include visualization of intraluminal thrombus or a filling defect and lack of flow, or flow voids.² Signs suggestive of DVST on standard brain MR imaging are reported in the literature with highly variable diagnostic accuracy and can be difficult to interpret in daily practice.^2,6–8 Understanding the diagnostic performance of routine MR imaging for the evaluation of DVST is especially important when DVST is not clinically suspected or CT or MR venography has not been ordered. A false-positive interpretation of DVST based on routine MR imaging will lead to unnecessary patient anxiety, require further imaging and associated health care costs, and increase patient risk from exposure to contrast media or radiation from CTV. False-negative interpretations can lead to devastating complications such as intracranial venous hypertension, hemorrhage, and venous infarction. The aim of this study was to assess the performance characteristics and interrater reliability of signs of DVST, not including cortical or deep vein thrombosis, on routine brain MR imaging, including T1, T2, T2*-weighted gradient recalled-echo imaging (GRE), FLAIR, DWI, and postcontrast T1 sequences in comparison with CEMRV and CTV as the reference standard.     

Evidence for reciprocal interaction effects among adults with self-injury and their caregivers

Patterns of caregiver responses to client adaptive behavior were compared between adults with intellectual disabilities with and without self-injurious behavior. Participants with moderate to profound intellectual disability and self-injury (n=89) and age/IQ matched control participants (n=20) were selected from a large sample of adults living in a regional residential center. Approximately 45 minutes of direct observation data were collected for each participant during unstructured leisure time. Data were sequentially analyzed and Yule's Q scores derived and compared among groups. Results indicated that caregivers were more responsive to prosocial initiations and adaptive engagement among individuals with severe self-injurious behavior than to those with mild or no self-injurious behavior and that these responses were more likely to be in the form of a demand.     

Low-income African-American mothers' perception of exposure to racial discrimination and infant birth weight

We performed a hospital-based case-control study of African-American mothers to explore the relation between a mother's perception of exposure to racial discrimination during pregnancy and very low birth weight. We administered a structured questionnaire to low-income mothers of very low birth weight (<1500 gm; N = 25) and non-low birth weight (>2500 gm; N = 60) infants. The unadjusted and adjusted odds ratio of very low birth weight for maternal exposure to racial discrimination were 1.9 (0.5-6.6) and 3.2 (0.9-11.3), respectively. We conclude that maternal perception of exposure to racial discrimination during pregnancy may be associated with very low birth weight in their infants.     

Peritonitis due to Leuconostoc species in a child receiving peritoneal dialysis

Leuconostoc species are rarely pathogenic in humans, but may cause infection in patients at risk. A 7-year-old girl with p-ANCA-positive crescentic glomerulonephritis, treated with peritoneal dialysis, developed peritonitis due to Leuconostoc species. She had a history of treatment with vancomycin and a brief course of immunosuppressive therapy. The peritonitis responded well to ampicillin therapy. To date, only 47 cases of Leuconostoc infection, including our patient, have been reported in the medical literature; 25 of the cases occurred in children. Only 1 prior case has been reported in the setting of peritoneal dialysis. The risk factors for Leuconostoc infections are not clear, but commonly associated conditions include immunocompromised status and indwelling medical devices. Leuconostoc species are easily misidentified as streptococci in culture, but they possess inherent resistance to vancomycin despite sensitivity to most other antibiotics. In patients with gram-positive peritonitis, Leuconostoc should be considered as a possible etiological agent, particularly if vancomycin resistance is noted in an organism thought to be a Streptococcus species.     

Intravitreal injection of adeno-associated viral vectors results in the transduction of different types of retinal neurons in neonatal and adult rats: a comparison with lentiviral vectors

Replication-deficient viral vectors encoding the marker gene green fluorescent protein (GFP) were injected into the vitreous of newborn, juvenile (P14), and adult rats. We tested two different types of modified virus: adeno-associated viral-2-GFP (AAV-GFP) and lentiviral-GFP vectors (LV-GFP). The extent of retinal cell transduction in different-aged animals was compared 7, 21, and 70 days after eye injections. At all postinjection times, LV-GFP transduction was mostly limited to pigment epithelium and cells in sclera and choroid. In contrast, transduction of large numbers of neural retinal cells was seen 21 and 70 days after AAV-GFP injections. AAV-GFP predominantly transduced neurons, although GFP-positive Müller cells were seen. All neuronal classes were labeled, but the extent of transduction for a given class varied depending on injection age. After P0 injections about 50% of transduced cells were photoreceptors and 30-40% were amacrine or bipolar cells. After adult injections 60-70% of transduced cells were retinal ganglion cells. In adults many GFP-positive retinal axons were traced through the optic nerve/tract and terminal arbors were visualized in central targets.     

Hyperhomocysteinemia evoked by folate depletion: effects on coronary and carotid arterial function

High circulating concentrations of homocysteine (ie, hyperhomocysteinemia [Hhcy]) impair the vascular function of peripheral conduit arteries and arterioles perfusing splanchnic and skeletal muscle regions. The effects of HHcy on coronary resistance vessel function and other indexes of vascular function, ie, arterial permeability and stiffening, are unclear. We tested the hypotheses that HHcy impairs coronary resistance vessel reactivity; increases carotid arterial permeability; and initiates arterial stiffening. Male rats that consumed folate-replete (CON, n=44) or folate-deplete (HHcy, n=48) chow for 4 to 5 weeks had total plasma homocysteine concentrations of 7+/-2 or 58+/-4 micromol/L, respectively. Maximal acetylcholine-evoked relaxation (approximately 40% vs approximately 60%) and tension development from baseline in response to nitric oxide synthase inhibition (approximately 20% vs approximately 40%) were lower (both P<0.05) in coronary resistance vessels (approximately 120 microm, internal diameter) isolated from HHcy versus CON animals, respectively, whereas sodium nitroprusside-evoked relaxation and contractile responses to serotonin and potassium chloride were similar between groups. Permeability to 4400 MW and 65 000 MW fluorescently labeled (TRITC) dextran reference macromolecules (quantitative fluorescence microscopy) was approximately 44% and approximately 24% greater (P<0.05), respectively, in carotid arteries from HHcy versus CON rats. Maximal strain, evaluated by using a vessel elastigraph, was less ( approximately 32% vs 42%, P<0.05) in carotid arterial segments from HHcy versus CON animals, respectively. Finally, estimates of oxidative (copper-zinc+manganese superoxide dismutase activity) and glycoxidative (pentosidine) stress were elevated (P<0.05) in arterial tissue from HHcy versus CON rats. These findings suggest that moderately severe HHcy evoked by folate-depletion impairs endothelium-dependent relaxation of coronary resistance vessels, increases carotid arterial permeability, and initiates arterial stiffening. HHcy may produce these effects by a mechanism associated with increased oxidative and glycoxidative stress.