The Magellanic Corona as the key to the formation of the Magellanic Stream.

The dominant gaseous structure in the Galactic halo is the Magellanic Stream. This extended network of neutral and ionized filaments surrounds the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), the two most massive satellite galaxies of the Milky Way1-4. Recent observations indicate that the LMC and SMC are on their first passage around the Galaxy5, that the Magellanic Stream is made up of gas stripped from both clouds2,6,7 and that the majority of this gas is ionized8,9. Although it has long been suspected that tidal forces10,11 and ram-pressure stripping12,13 contributed to the formation of the Magellanic Stream, models have not been able to provide a full understanding of its origins3. Several recent developments-including the discovery of dwarf galaxies associated with the Magellanic group14-16, determination of the high mass of the LMC17, detection of highly ionized gas near stars in the LMC18,19 and predictions of cosmological simulations20,21-support the existence of a halo of warm (roughly 500,000 kelvin) ionized gas around the LMC (the 'Magellanic Corona'). Here we report that, by including this Magellanic Corona in hydrodynamic simulations of the Magellanic Clouds falling onto the Milky Way, we can reproduce the Magellanic Stream and its leading arm. Our simulations explain the filamentary structure, spatial extent, radial-velocity gradient and total ionized-gas mass of the Magellanic Stream. We predict that the Magellanic Corona will be unambiguously observable via high-ionization absorption lines in the ultraviolet spectra of background quasars lying near the LMC.

A Pragmatic Randomized Trial Comparing Surgical Clipping and Endovascular Treatment of Unruptured Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Surgical clipping and endovascular treatment are commonly used in patients with unruptured intracranial aneurysms. We compared the safety and efficacy of the 2 treatments in a randomized trial. MATERIALS AND METHODS: Clipping or endovascular treatments were randomly allocated to patients with one or more 3- to 25-mm unruptured intracranial aneurysms judged treatable both ways by participating physicians. The study hypothesized that clipping would decrease the incidence of treatment failure from 13% to 4%, a composite primary outcome defined as failure of aneurysm occlusion, intracranial hemorrhage during follow-up, or residual aneurysms at 1 year, as adjudicated by a core lab. Safety outcomes included new neurologic deficits following treatment, hospitalization of >5 days, and overall morbidity and mortality (mRS > 2) at 1 year. There was no blinding. RESULTS: Two hundred ninety-one patients were enrolled from 2010 to 2020 in 7 centers. The 1-year primary outcome, ascertainable in 290/291 (99%) patients, was reached in 13/142 (9%; 95% CI, 5%-15%) patients allocated to surgery and in 28/148 (19%; 95% CI, 13%-26%) patients allocated to endovascular treatments (relative risk: 2.07; 95% CI, 1.12-3.83; P = .021). Morbidity and mortality (mRS >2) at 1 year occurred in 3/143 and 3/148 (2%; 95% CI, 1%-6%) patients allocated to surgery and endovascular treatments, respectively. Neurologic deficits (32/143, 22%; 95% CI, 16%-30% versus 19/148, 12%; 95% CI, 8%-19%; relative risk: 1.74; 95% CI, 1.04-2.92; P = .04) and hospitalizations beyond 5 days (69/143, 48%; 95% CI, 40%-56% versus 12/148, 8%; 95% CI, 5%-14%; relative risk: 0.18; 95% CI, 0.11-0.31; P < .001) were more frequent after surgery. CONCLUSIONS: Surgical clipping is more effective than endovascular treatment of unruptured intracranial aneurysms in terms of the frequency of the primary outcome of treatment failure. Results were mainly driven by angiographic results at 1 year.

Transcriptomes of the major human pancreatic cell types.

AIMS/HYPOTHESIS: We sought to determine the mRNA transcriptome of all major human pancreatic endocrine and exocrine cell subtypes, including human alpha, beta, duct and acinar cells. In addition, we identified the cell type-specific distribution of transcription factors, signalling ligands and their receptors. METHODS: Islet samples from healthy human donors were enzymatically dispersed to single cells and labelled with cell type-specific surface-reactive antibodies. Live endocrine and exocrine cell subpopulations were isolated by FACS and gene expression analyses were performed using microarray analysis and quantitative RT-PCR. Computational tools were used to evaluate receptor-ligand representation in these populations. RESULTS: Analysis of the transcriptomes of alpha, beta, large duct, small duct and acinar cells revealed previously unrecognised gene expression patterns in these cell types, including transcriptional regulators HOPX and HDAC9 in the human beta cell population. The abundance of some regulatory proteins was different from that reported in mouse tissue. For example, v-maf musculoaponeurotic fibrosarcoma oncogene homologue B (avian) (MAFB) was detected at equal levels in adult human alpha and beta cells, but is absent from adult mouse beta cells. Analysis of ligand-receptor interactions suggested that EPH receptor-ephrin communication between exocrine and endocrine cells contributes to pancreatic function. CONCLUSIONS/INTERPRETATION: This is the first comprehensive analysis of the transcriptomes of human exocrine and endocrine pancreatic cell types-including beta cells-and provides a useful resource for diabetes research. In addition, paracrine signalling pathways within the pancreas are shown. These results will help guide efforts to specify human beta cell fate by embryonic stem cell or induced pluripotent stem cell differentiation or genetic reprogramming.

Bradykinin-evoked sensitization of airway sensory nerves: a mechanism for ACE-inhibitor cough.

Cough accompanied by an increased sensitivity of the cough reflex is the most common symptom of inflammatory airway disease. This symptom is also frequently reported in patients receiving angiotensin-converting enzyme (ACE) inhibitors as therapy for heart failure or hypertension, although the underlying mechanism is unknown. We have investigated the possibility that the inflammatory peptide bradykinin, normally degraded by ACE, causes sensitization of airway sensory nerves and an enhancement of the cough reflex in conscious guinea pigs. Treatment of guinea pigs for two weeks with captopril led to an increased cough response to inhaled citric acid, which was prevented by concomitant treatment with the bradykinin receptor antagonist icatibant. A similar icatibant-sensitive enhancement of citric acid-evoked cough was seen in untreated animals after prior inhalation of bradykinin, although cough evoked by hypertonic saline was unaffected. In electrophysiological studies performed in vitro, responses of single vagal C fibers to capsaicin, applied to receptive fields of single-fiber units in the trachea, were also markedly increased after perfusion with bradykinin, whereas A delta fiber responses to hypertonic saline were unaffected. These results indicate that bradykinin-evoked sensitization of airway sensory nerves may underlie the pathogenesis of ACE-inhibitor cough. Bradykinin receptor antagonists may be of benefit in treating chronic cough seen with this and other inflammatory conditions.

Oblique sub-costal transversus abdominis plane (TAP) catheters: an alternative to epidural analgesia after upper abdominal surgery.

SUMMARY: The authors present three cases where catheters placed in the oblique sub-costal transversus abdominis plane provided prolonged analgesia after upper abdominal surgery. Patient 1 was admitted with severe sepsis following major hepatobiliary surgery. Bilateral catheters facilitated weaning from mechanical ventilation and provided adequate analgesia for 4 days. Patient 2 underwent emergency laparotomy for intestinal obstruction having refused consent for epidural analgesia. The transversus abdominis plane catheters provided a significant opioid sparing effect. A unilateral catheter offered rescue analgesia in patient 3 when the epidural catheter was displaced. We put forward a case for oblique sub-costal transversus abdominis plane catheters as an alternative to epidural analgesia after upper abdominal surgery.

Unruptured intracranial aneurysms: their illusive natural history and why subgroup statistics cannot provide normative criteria for clinical decisions or selection criteria for a randomized trial.

There is currently no evidence that treatment of unruptured aneurysms is beneficial. Confronted with the uncertainty, many clinicians are attracted by an individual calculus of risks using numbers extracted from subgroup statistics of observational studies or natural history data. The so-called natural history of unruptured aneurysms refers to a purely man-made ratio of events divided by the number of untreated patients identified by imaging, a ratio heavily influenced by referral patterns and arbitrary clinical decisions. Available studies lacked prespecified hypotheses, exposing all analyses to sampling error and bias, and sample sizes were too small to provide reliable subgroup statistics. Far from being "natural kinds" of aneurysms, subgroups were post-hoc creations. Resulting data-driven statistics can only be exploratory, the error too uncontrollable to serve for clinical decisions. A randomized trial is in order, but selection according to fixed size criteria is ill-advised, given the imprecision of imaging, the influence of other factors such as location, previous history, multiplicity of lesions, risks of treatment, age and the danger of arbitrarily excluding from a long trial a large segment of the population with aneurysms for whom the research question is most pertinent.

Activation of large conductance potassium channels inhibits the afferent and efferent function of airway sensory nerves in the guinea pig.

Sensory nerves play an important role in airway disease by mediating central reflexes such as cough, and local axon reflexes resulting in the peripheral release of neuropeptides. We have tested whether the benzimidazolone compound, NS1619, an opener of large conductance calcium-activated potassium (BK Ca) channels, inhibits the activity of sensory fibers, and central and local airway reflexes in guinea pig airways. In in vitro single fiber recording experiments, NS1619 applied to identified receptive fields in the trachea inhibited the firing of A(delta)-fibers evoked by hypertonic saline and distilled water, and bradykinin-evoked firing of C-fibers. Electrically evoked nonadrenergic noncholinergic contractions of isolated bronchi mediated by the release of neurokinin A (NKA) from C-fibers, but not those elicited by exogenous NKA, were inhibited by NS1619. These effects of NS1619 were prevented by iberiotoxin, a selective blocker of BK Ca channels. In conscious guinea pigs, cough evoked by aerosolized citric acid was also inhibited by NS1619. These data show that BK Ca channel activation inhibits sensory nerve activity, resulting in a reduction of both afferent and efferent function. BK Ca channel openers may therefore be of potential benefit in reducing neurogenic inflammation and central reflexes seen during inflammatory conditions of the airways, and may represent a new class of antitussive drug.

Modulation of cholinergic neural bronchoconstriction by endogenous nitric oxide and vasoactive intestinal peptide in human airways in vitro.

Human airway smooth muscle possesses an inhibitory nonadrenergic noncholinergic neural bronchodilator response mediated by nitric oxide (NO). In guinea pig trachea both endogenous NO and vasoactive intestinal peptide (VIP) modulate cholinergic neural contractile responses. To identify whether endogenous NO or VIP can modulate cholinergic contractile responses in human airways in vitro, we studied the effects of specific NO synthase inhibitors and the peptidase alpha-chymotrypsin on contractile responses evoked by electrical field stimulation (EFS) at three airway levels. Endogenous NO, but not VIP, was shown to inhibit cholinergic contractile responses at all airway levels but this inhibition was predominantly in trachea and main bronchus and less marked in segmental and subsegmental bronchi. To elucidate the mechanism of this modulation we then studied the effects of endogenous NO on acetylcholine (ACh) release evoked by EFS from tracheal smooth muscle strips. We confirmed that release was neural in origin, frequency dependent, and that endogenous NO did not affect ACh release. These findings show that endogenous NO, but not VIP, evoked by EFS can inhibit cholinergic neural responses via functional antagonism of ACh at the airway smooth muscle and that the contribution of this modulation is less marked in lower airways.

Alberta Stroke Program Early CT Scoring of CT perfusion in early stroke visualization and assessment.

BACKGROUND AND PURPOSE: Qualitative CT perfusion (CTP) assessment by using the Alberta Stroke Program Early CT Score (ASPECTS) allows rapid calculation of infarct extent for middle cerebral artery infarcts. Published thresholds exist for noncontrast CT (NCCT) ASPECTS, which may distinguish outcome/complication risk, but early ischemic signs are difficult to detect. We hypothesized that different ASPECTS thresholds exist for CTP parameters versus NCCT and that these may be superior at predicting clinical and radiologic outcome in the acute setting. MATERIALS AND METHODS: Thirty-six baseline acute stroke NCCT and CTP studies within 3 hours of symptoms were blindly reviewed by 3 neuroradiologists, and ASPECTS were assigned. Treatment response was defined as major neurologic improvement when a > or =8-point National Institutes of Health Stroke Scale improvement at 24 hours occurred. Follow-up NCCT ASPECTS and 90-day modified Rankin score (mRS) were radiologic and clinical reference standards. Receiver operating characteristic curves derived optimal thresholds for outcome. RESULTS: Cerebral blood volume and NCCT ASPECTS had similar radiologic correlations (0.6 and 0.5, respectively) and best predicted infarct size in the absence of major neurologic improvement. A NCCT ASPECT threshold of 7 and a cerebral blood volume threshold of 8 discriminated patients with poor follow-up scans (P < .0002 and P = .0001) and mRS < or =2 (P = .001 and P < .001). Only cerebral blood volume predicted major neurologic improvement (P = .02). Interobserver agreement was substantial (intraclass correlation coefficient, 0.69). Cerebral blood volume ASPECTS sensitivity, specificity, positive predictive value, and negative predictive value for clinical outcome were 60%, 100%, 100%, and 45%, respectively. No patients with cerebral blood volume ASPECTS <8 achieved good clinical outcome. CONCLUSION: Cerebral blood volume ASPECTS is equivalent to NCCT for predicting radiologic outcome but may have an additional benefit in predicting patients with major neurologic improvement.

Trial on endovascular treatment of unruptured aneurysms (TEAM): study monitoring and rationale for trial interruption or continuation.

Preventive treatment of unruptured intracranial aneurysms is often performed but has never been proved beneficial as compared to conservative management. In a context of uncertainty, the 'best treatment' that can be offered to each individual is a chance to be treated and thus to be protected from rupture of the aneurysm, and an equal chance not to be treated, and hence to be exempted from possible immediate complications, using randomization. Such action is optimal unless or until an independent committee with privileged access to data judges that, given the comparative outcome of the 2 groups, preventive treatment or conservative management, is generally warranted. Potential reasons to interrupt such a study are reviewed, including insufficient recruitment, poor compliance, excessive cross-overs, unacceptable iatrogenia, and treatments being convincingly different or equivalent. We conclude that insufficient recruitment is the sole realistic event that could lead to premature interruption. This review may provide a deeper understanding of the principles justifying the necessity of the study.

Hydrogel versus Bare Platinum Coils in Patients with Large or Recurrent Aneurysms Prone to Recurrence after Endovascular Treatment: A Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Some patients are at high risk of aneurysm recurrence after endovascular treatment: patients with large aneurysms (Patients Prone to Recurrence After Endovascular Treatment PRET-1) or with aneurysms that have previously recurred after coiling (PRET-2). We aimed to establish whether the use of hydrogel coils improved efficacy outcomes compared with bare platinum coils. MATERIALS AND METHODS: PRET was an investigator-led, pragmatic, multicenter, parallel, randomized (1:1) trial. Randomized allocation was performed separately for patients in PRET-1 and PRET-2, by using a Web-based platform ensuring concealed allocation. The primary outcome was a composite of a residual/recurrent aneurysm, adjudicated by a blinded core laboratory, or retreatment, intracranial bleeding, or mass effect during the 18-month follow-up. Secondary outcomes included adverse events, mortality, and morbidity (mRS > 2). The hypothesis was that hydrogel would decrease the primary outcome from 50% to 30% at 18 months, necessitating 125 patients per group (500 for PRET-1 and PRET-2). RESULTS: The trial was stopped once 250 patients in PRET-1 and 197 in PRET-2 had been recruited because of slow accrual. A poor primary outcome occurred in 44.4% (95% CI, 35.5%-53.2%) of those in PRET-1 allocated to platinum compared with 52.5% (95% CI, 43.4%-61.6%) of patients allocated to hydrogel (OR, 1.387; 95% CI, 0.838-2.295; P = .20) and in 49.0% (95% CI, 38.8%-59.1%) in PRET-2 allocated to platinum compared with 42.1% (95% CI, 32.0%-52.2%) allocated to hydrogel (OR, 0.959; 95% CI, 0.428-1.342; P = .34). Adverse events and morbidity were similar. There were 3.6% deaths (1.4% platinum, 5.9% hydrogel; P = .011). CONCLUSIONS: Coiling of large and recurrent aneurysms is safe but often poorly effective according to angiographic results. Hydrogel coiling was not shown to be better than platinum.

Identification of penumbra and infarct in acute ischemic stroke using computed tomography perfusion-derived blood flow and blood volume measurements.

BACKGROUND AND PURPOSE: We investigated whether computed tomography (CT) perfusion-derived cerebral blood flow (CBF) and cerebral blood volume (CBV) could be used to differentiate between penumbra and infarcted gray matter in a limited, exploratory sample of acute stroke patients. METHODS: Thirty patients underwent a noncontrast CT (NCCT), CT angiography (CTA), and CT perfusion (CTP) scan within 7 hours of stroke onset, NCCT and CTA at 24 hours, and NCCT at 5 to 7 days. Twenty-five patients met the criteria for inclusion and were subsequently divided into 2 groups: those with recanalization at 24 hours (n=16) and those without (n=9). Penumbra was operationally defined as tissue with an admission CBF <25 mL x 100 g(-1) x min(-1) that was not infarcted on the 5- to 7-day NCCT. Logistic regression was applied to differentiate between infarct and penumbra data points. RESULTS: For recanalized patients, CBF was significantly lower (P<0.05) for infarct (13.3+/-3.75 mL x 100 g(-1) x min(-1)) than penumbra (25.0+/-3.82 mL x 100 g(-1) x min(-1)). CBV in the penumbra (2.15+/-0.43 mL x 100 g(-1)) was significantly higher than contralateral (1.78+/-0.30 mL x 100 g(-1)) and infarcted tissue (1.12+/-0.37 mL x 100 g(-1)). Logistic regression using an interaction term (CBFxCBV) resulted in sensitivity, specificity, and accuracy of 97.0%, 97.2%, and 97.1%, respectively. The interaction term resulted in a significantly better (P<0.05) fit than CBF or CBV alone, suggesting that the CBV threshold for infarction varies with CBF. For patients without recanalization, CBF and CBV for infarcted regions were 15.1+/-5.67 mL x 100 g(-1) x min(-1) and 1.17+/-0.41 mL x 100 g(-1), respectively. CONCLUSIONS: We have shown in a limited sample of patients that CBF and CBV obtained from CTP can be sensitive and specific for infarction and should be investigated further in a prospective trial to assess their utility for differentiating between infarct and penumbra.

Correlation of carotid stenosis diameter and cross-sectional areas with CT angiography.

PURPOSE: Carotid stenosis quantification traditionally uses measurements of narrowest stenosis diameter. The stenotic carotid lumen, however, is often irregularly shaped. New PACS workstation tools allow for more precise calculation of carotid geometry. We compare the narrowest stenosis diameter with 2D area stenosis measurements, with the hypothesis that the narrowest diameter is a good predictor of the more precise area measurement. METHODS: Two neuroradiologists evaluated 178 stenosed carotids in a blinded protocol. Carotid artery bulb stenosis was identified on axial CT angiography and measured in millimeters at its narrowest diameter. An AGFA Impax 4.5 Volume Tool (VT) using Hounsfield units was used to estimate the cross-sectional area of the contrast luminogram. Pearson correlation coefficients were calculated between the millimeter stenosis and the VT area, as well as between the VT area and the calculated area (radius based on narrowest diameter). Regression analysis was performed with the VT area and narrowest diameter datasets. RESULTS: Excellent interobserver correlation (correlation coefficients, 0.71-0.85; 2-tailed significance = .01) permitted averaging of measurement data. There is excellent correlation between the VT area and the narrowest diameter (correlation coefficient, 0.88; n = 176). The VT area was generally greater than the calculated area by an average of 2.77 mm2. There was excellent correlation between the VT area and the calculated area (correlation coefficient, 0.87; n = 176). Regression analysis shows the ability of the diameter measurements to predict corresponding area stenosis. CONCLUSION: Although some carotid stenoses are irregularly shaped and noncircular, measurement of the narrowest stenosis is a reasonably reliable predictor of the cross-sectional area.

Quantification of carotid stenosis on CT angiography.

PURPOSE: Carotid artery stenosis quantification uses percent diameter ratios from conventional angiography. Multidetector high-speed CT angiography (CTA) allows direct millimeter measurement of carotid stenosis. We hypothesize a linear relationship between millimeter stenosis measurements and derived percent, alleviating cumbersome ratio calculations. METHODS: Two neuroradiologists separately reviewed CTAs of 268 carotid arteries, blinded to other information. The narrowest portion of each carotid stenosis was measured in millimeters from axial source images. Distal internal carotid arteries (ICAs) were measured beyond the bulb, where walls are parallel. North American Symptomatic Carotid Endarterectomy Trial (NASCET)-style ratios were calculated for each ICA, except for suspected near-occlusions. Interobserver agreement was calculated for all measurements. Correlation coefficients were calculated comparing millimeter and derived percent stenosis, followed by regression analysis. Sensitivity and specificity values tested validity. RESULTS: Interobserver agreement correlations were excellent, from 0.78 to 0.89 (2-tailed P

Association between calcification of the cervical carotid artery bifurcation and white matter ischemia.

BACKGROUND AND PURPOSE: The association of cervical carotid artery bifurcation calcification to future stroke risk is unknown, though coronary artery calcification is a proven indicator of heart disease risk. Severity of white matter change has been correlated with future stroke risk. We sought to use white matter severity grade on CT as a surrogate predictor of relative future stroke risk and thus correlate white matter and future stroke risk with carotid calcification grade. METHODS: We retrospectively reviewed unenhanced neck and brain CTs in 209 patients. Carotid calcification degree was scored by the Agatston method, adapted from that commonly used to quantify coronary artery calcification. White matter change severity was scored by the European Task Force for Age-Related White Matter Change scale. Both scores were measured blinded to each other, and to age and sex covariables. Association was tested by univariate and multivariate analyses. RESULTS: Both carotid calcification and white matter scores were strongly, and independently, associated with increasing age (r = 0.61, P < .001; and r = 0.67, P < .001, respectively). Despite apparent association between carotid calcification and white matter scores on univariate analysis, there was no independent effect evident after adjusting for age as a covariant (r = 0.07, P = .14). Sex had no independent effect on white matter scores, though men had a marginally higher mean calcified carotid plaque load than women after controlling for age (P = .008). CONCLUSIONS: Carotid calcification scores do not independently predict severity of white matter ischemia. Future stroke risk, assessed by white matter severity scores, cannot be predicted from carotid calcium scores.

Diagnosing carotid stenosis near-occlusion by using CT angiography.

BACKGROUND/PURPOSE: Identification of carotid near-occlusion is essential before calculation of percent stenosis because stroke risk is lower than other severe stenosis and the treatment benefit is less. Calculations with reduced distal diameters are fallacious. CT angiography (CTA) is convenient and accurately quantifies internal carotid artery (ICA) stenosis. METHODS: In a blinded protocol, 268 carotid artery CTAs for known or suspected carotid disease were independently evaluated by 2 neuroradiologists. All carotid arteries were measured in millimeters at the narrowest diameter of the stenotic bulb, distal ICA well beyond the tapering bulb, and distal external carotid artery (ECA). Near-occlusions were independently identified, with disagreements settled by consensus meeting. Receiver operating characteristic (ROC) curve analysis defined the threshold values that best predicted near-occlusion according to (1) ICA stenosis, (2) distal ICA, (3) distal ICA: contralateral distal ICA, and (4) distal ICA: ECA. Paired permutations of variables were evaluated. RESULTS: Forty-two near-occlusion distal ICAs were identified. The ROC-derived threshold values determined near-occlusion carotid stenosis with a sensitivity range, 90.2-97.3; specificity, 84.1-89.9; positive predictive value (PPV), 61.3-66.7; and negative predictive value (NPV), 96.7-99.4. Ranges for paired permutations were also determined: sensitivity, 82.9-91.9; specificity, 95.4-96.8; PPV, 78.6-85.7; and NPV, 96.3-98.4. CONCLUSIONS: Threshold values provide guidelines for CTA interpretation when assessing carotid artery disease and the presence of near-occlusion. Ultimate identification of near-occlusion requires the interpreter's judgment, with attention to the following criteria: (1) notable stenosis of the ICA bulb and (2) distal ICA caliber reduction compared with (A) expected size, (B) contralateral ICA, and (C) ipsilateral ECA. Near-occlusion distal ICAs can be reliably identified on CTA.

Carotid Near-Occlusion: A Comprehensive Review, Part 1--Definition, Terminology, and Diagnosis.

Carotid near-occlusion is distal ICA luminal collapse beyond a tight stenosis, where the distal lumen should not be used for calculating percentage stenosis. Near-occlusion with full ICA collapse is well-known, with a threadlike lumen. However, near-occlusion without collapse is often subtle and can be overlooked as a usual severe stenosis. More than 10 different terms have been used to describe near-occlusion, sometimes causing confusion. This systematic review presents what is known about carotid near-occlusion. In this first part, the foci are definition, terminology, and diagnosis.

Carotid Near-Occlusion: A Comprehensive Review, Part 2--Prognosis and Treatment, Pathophysiology, Confusions, and Areas for Improvement.

In Part 1 of this review, the definition, terminology, and diagnosis of carotid near-occlusion were presented. Carotid near-occlusions (all types) showed a lower risk of stroke than other severe stenoses. However, emerging evidence suggests that the near-occlusion prognosis with full collapse (higher risk) differs from that without full collapse (lower risk). This systematic review presents what is known about carotid near-occlusion. In this second part, the foci are prognosis and treatment, pathophysiology, the current confusion about near-occlusion, and areas in need of future improvement.

Computed tomographic excretory urography features of intramural ectopic ureters in 10 dogs.

OBJECTIVES: To describe the morphologic and morphometric computed tomographic excretory urography features of intramural ectopic ureters in dogs. METHODS: Retrospective evaluation of computed tomographic excretory urography studies in 10 dogs with surgical and/or cystoscopically confirmed intramural ectopic ureters. All studies were assessed for ureteral ectopia, dilatation, tortuosity, ureterovesicular junction morphology and ureteral orifice location. RESULTS: A total of 14 intramural ectopic ureters were confirmed at surgery/cystoscopy with reviewers correctly identifying 100% (14/14). Abnormalities on computed tomographic excretory urography included ureteral dilatation (7), ureteral tortuosity (3), lack of a normal ureterovesicular junction (14), urethral ureteral orifice location (14) and lack of ureteral divergence (14). CLINICAL SIGNIFICANCE: Lack of a normal ureterovesicular junction, a urethral-ureteral orifice location and lack of ureteral divergence are common computed tomographic excretory urography findings in dogs with intramural ectopic ureters. This technique requires further investigation to determine whether it might allow differentiation of intramural and extramural ectopic ureters.

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.