Cheemun Lum

The Ottawa Hospital, Ottawa, Ontario, Canada

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Publications (93)355.41 Total impact

  • No preview · Article · May 2016 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
  • [Show abstract] [Hide abstract] ABSTRACT: Background—The ESCAPE trial used innovative imaging and aggressive target time metrics to demonstrate benefit of endovascular treatment in patients with acute ischemic stroke. We analyze the impact of time on clinical outcome and the effect of patient, hospital and health system characteristics on workflow within the trial. Methods and Results—Relationship between outcome [modified Rankin Scale (mRS)] and interval times was modeled using logistic regression. Association between time intervals (stroke onset to arrival in endovascular capable hospital, to qualifying CT, to groin puncture and to reperfusion) and patient, hospital and health system characteristics were modeled using negative binomial regression. Every 30-minute increase in CT-to-reperfusion time reduced the probability of achieving a functionally independent outcome (90 day mRS 0-2) by 8.3%. (p=0.006). Symptom-onset-to-imaging time was not associated with outcome (p>0.05). Onset to endovascular hospital arrival time was 42% (34 mins) longer among patients receiving intravenous alteplase at the referring hospital (drip and ship) vs. direct transfer (mothership). CT-to-groin-puncture time was 15% (8 mins) shorter among patients presenting during work hours vs. off hours, 41% (24 min) shorter in drip-ship patients vs. mothership and 43% (22 min) longer when general anesthesia was administered. Balloon-guide-catheter use during endovascular procedure shortened puncture-to-reperfusion time by 21% (8 mins). Conclusions—Imaging-to-reperfusion time is a significant predictor of outcome in the ESCAPE trial. Inefficiencies in triaging, off-hour presentation, intravenous alteplase administration, GA utilization and endovascular techniques offer major opportunities for improvement in workflow. Clinical Trial Registration Information— Identifier: NCT01778335.
    No preview · Article · Apr 2016 · Circulation
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    [Show abstract] [Hide abstract] ABSTRACT: Although intravenous thrombolysis increases the probability of a good functional outcome in carefully selected patients with acute ischemic stroke, a substantial proportion of patients who receive thrombolysis do not have a good outcome. Several recent trials of mechanical thrombectomy appear to indicate that this treatment may be superior to thrombolysis. We therefore conducted a systematic review and meta-analysis to evaluate the clinical effectiveness and safety of new-generation mechanical thrombectomy devices with intravenous thrombolysis (if eligible) compared with intravenous thrombolysis (if eligible) in patients with acute ischemic stroke caused by a proximal intracranial occlusion. We systematically searched seven databases for randomized controlled trials published between January 2005 and March 2015 comparing stent retrievers or thromboaspiration devices with best medical therapy (with or without intravenous thrombolysis) in adults with acute ischemic stroke. We assessed risk of bias and overall quality of the included trials. We combined the data using a fixed or random effects meta-analysis, where appropriate. We identified 1579 studies; of these, we evaluated 122 full-text papers and included five randomized control trials (n=1287). Compared with patients treated medically, patients who received mechanical thrombectomy were more likely to be functionally independent as measured by a modified Rankin score of 0-2 (odds ratio, 2.39; 95% confidence interval, 1.88-3.04; I 2 =0%). This finding was robust to subgroup analysis. Mortality and symptomatic intracerebral hemorrhage were not significantly different between the two groups. Mechanical thrombectomy significantly improves functional independence in appropriately selected patients with acute ischemic stroke.
    Full-text · Article · Apr 2016 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
  • [Show abstract] [Hide abstract] ABSTRACT: Introduction: The only direct sign of sinus thrombosis on non-contrast computerized tomography (NCCT) is the hyperdense sign. The purpose of our study was to assess quantitative parameters for diagnosis of superficial venous sinus thrombosis and to compare these quantitative criteria with the current standard of qualitative evaluation. Methods: This retrospective case-control study included 18 patients with acute superficial sinus thrombosis and 18 matched controls. Three blinded readers independently evaluated the NCCT for the presence of hyperdense sign using axial slices only followed by axial slices with multiplanar reformats. Absolute attenuation values and ratios were calculated for thrombosed and non-thrombosed sinuses: Ratiotarget sinus/lowest attenuation sinus, Ratiotarget sinus/basilar artery, Ratiotarget sinus/internal carotid artery, Ratiotarget sinus/temporal lobe, and Ratiotarget sinus/frontal lobe. Results: There was a significant difference in absolute attenuation values and ratios between thrombosed and non-thrombosed sinuses, with the absolute attenuation and the Ratiotarget sinus/lowest attenuation sinus being the most differentiating. The mean attenuation for thrombosed sinuses was 69 Hounsfield units (HU) (95 % CI 65-72 HU) vs. 52 HU (95 % CI 51-54) for non-thrombosed, P < 0.0001. The mean Ratiotarget/lowest attenuation was 1.5 (95 % CI 1.4-1.6) for thrombosed sinuses vs. 1.1 (95 % CI 1.0-1.1) for non-thrombosed, P < 0.0001. Optimal thresholds of 62 HU and 1.3 yielded sensitivities of 81 and 84 %, respectively. Hyperdense sign had a sensitivity of 63 % on axial images and 67 % with the addition of multiplanar reformats. Conclusion: Density measurements result in substantial improvement over visual inspection in the diagnosis of superficial venous sinus thrombosis on NCCT.
    No preview · Article · Apr 2016 · Neuroradiology
  • [Show abstract] [Hide abstract] ABSTRACT: Objective: To evaluate the extracranial venous anatomy with contrast-enhanced MR venogram (CE-MRV) in patients without multiple sclerosis (MS), and assess the prevalence of various venous anomalies such as asymmetry and stenosis in this population. Materials and methods: We prospectively recruited 100 patients without MS, aged 18-60 years, referred for contrast-enhanced MRI. They underwent additional CE-MRV from skull base to mediastinum on a 3T scanner. Exclusion criteria included prior neck radiation, neck surgery, neck/mediastinal masses or significant cardiac or pulmonary disease. Two neuroradiologists independently evaluated the studies to document asymmetry and stenosis in the jugular veins and prominence of collateral veins. Results: Asymmetry of internal jugular veins (IJVs) was found in 75 % of subjects. Both observers found stenosis in the IJVs with fair agreement. Most stenoses were located in the upper IJV segments. Asymmetrical vertebral veins and prominence of extracranial collateral veins, in particular the external jugular veins, was not uncommon. Conclusion: It is common to have stenoses and asymmetry of the IJVs as well as prominence of the collateral veins of the neck in patients without MS. These findings are in contrast to prior reports suggesting collateral venous drainage is rare except in MS patients. Key points: • The venous anatomy of the neck in patients without MS demonstrates multiple variants • Asymmetry and stenoses of the internal jugular veins are common • Collateral neck veins are not uncommon in patients without MS • These findings do not support the theory of chronic cerebrospinal venous insufficiency • MR venography is a useful imaging modality for assessing venous anatomy.
    No preview · Article · Mar 2016 · European Radiology
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    [Show abstract] [Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE: The goal of reperfusion therapy in acute ischemic stroke is to limit brain infarction. The objective of this study was to investigate whether the beneficial effect of endovascular treatment on functional outcome could be explained by a reduction in post-treatment infarct volume. METHODS: The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE) trial was a multicenter randomized open-label trial with blinded outcome evaluation. Among 315 enrolled subjects (endovascular treatment n=165; control n=150), 314 subject's infarct volumes at 24 to 48 hours on magnetic resonance imaging (n=254) or computed tomography (n=60) were measured. Post-treatment infarct volumes were compared by treatment assignment and recanalization/reperfusion status. Appropriate statistical models were used to assess relationship between baseline clinical and imaging variables, post-treatment infarct volume, and functional status at 90 days (modified Rankin Scale). RESULTS: Median post-treatment infarct volume in all subjects was 21 mL (interquartile range =65 mL), in the intervention arm, 15.5 mL (interquartile range =41.5 mL), and in the control arm, 33.5 mL (interquartile range =84 mL; P<0.01). Baseline National Institute of Health Stroke Scale (P<0.01), site of occlusion (P<0.01), baseline noncontrast computed tomographic scan Alberta Stroke Program Early CT score (ASPECTS) (P<0.01), and recanalization (P<0.01) were independently associated with post-treatment infarct volume, whereas age, sex, treatment type, intravenous alteplase, and time from onset to randomization were not (P>0.05). Post-treatment infarct volume (P<0.01) and delta National Institute of Health Stroke Scale (P<0.01) were independently associated with 90-day modified Rankin Scale, whereas laterality (left versus right) was not. CONCLUSIONS: These results support the primary results of the ESCAPE trial and show that the biological underpinning of the success of endovascular therapy is a reduction in infarct volume.
    Full-text · Article · Feb 2016 · Stroke
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    [Show abstract] [Hide abstract] ABSTRACT: Background Hematoma expansion is a major predictor of morbidity and mortality after intracerebral hemorrhage (ICH). Both baseline hematoma volume and the CT-angiogram (CTA) spot sign predict hematoma expansion. Because the CTA spot sign may represent foci of active hemorrhage, we hypothesized that patients with smaller baseline hematoma volumes are less likely to be spot sign positive, and therefore less likely to expand.
    Full-text · Article · Feb 2016 · International Journal of Stroke
  • [Show abstract] [Hide abstract] ABSTRACT: Purpose: Computed tomography perfusion (CTP) has been performed to predict which patients with aneurysmal subarachnoid hemorrhage are at risk of developing delayed cerebral ischemia (DCI). Patients with severe arterial narrowing may have significant reduction in perfusion. However, many patients have less severe arterial narrowing. There is a paucity of literature evaluating perfusion changes which occur with mild to moderate narrowing. The purpose of our study was to investigate serial whole-brain CTP/computed tomography angiography in aneurysm-related subarachnoid hemorrhage (aSAH) patients with mild to moderate angiographic narrowing. Methods: We retrospectively studied 18 aSAH patients who had baseline and follow-up whole-brain CTP/computed tomography angiography. Thirty-one regions of interest/hemisphere at six levels were grouped by vascular territory. Arterial diameters were measured at the circle of Willis. The correlation between arterial diameter and change in CTP values, change in CTP in with and without DCI, and response to intra-arterial vasodilator therapy in DCI patients was evaluated. Results: There was correlation among the overall average cerebral blood flow (CBF; R=0.49, p<0.04), mean transit time (R=-0.48, p=0.04), and angiographic narrowing. In individual arterial territories, there was correlation between changes in CBF and arterial diameter in the middle cerebral artery (R=0.53, p=0.03), posterior cerebral artery (R=0.5, p=0.03), and anterior cerebral artery (R=0.54, p=0.02) territories. Prolonged mean transit time was correlated with arterial diameter narrowing in the middle cerebral artery territory (R=0.52, p=0.03). Patients with DCI tended to have serial worsening of CBF compared with those without DCI (p=0.055). Conclusions: Our preliminary study demonstrates there is a correlation between mild to moderate angiographic narrowing and serial changes in perfusion in patients with aSAH. Patients developing DCI tended to have progressively worsening CBF compared with those not developing DCI.
    No preview · Article · Jan 2016 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
  • [Show abstract] [Hide abstract] ABSTRACT: Background and purpose: Perihematomal edema volume may be related to intracerebral hemorrhage (ICH) volume at baseline and, consequently, with hematoma expansion. However, the relationship between perihematomal edema and hematoma expansion has not been well established. We aimed to investigate the relationship among baseline perihematomal edema, the computed tomographic angiography spot sign, hematoma expansion, and clinical outcome in patients with acute ICH. Methods: Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT (PREDICT) was a prospective observational cohort study of ICH patients presenting within 6 hours from onset. Patients underwent computed tomography and computed tomographic angiography scans at baseline and 24-hour computed tomography scan. A post hoc analysis of absolute perihematomal edema and relative perihematomal edema (absolute perihematomal edema divided by ICH) volumes was performed on baseline computed tomography scans (n=353). Primary outcome was significant hematoma expansion (>6 mL or >33%). Secondary outcomes were early neurological deterioration, 90-day mortality, and poor outcome. Results: Absolute perihematomal edema volume was higher in spot sign patients (24.5 [11.5-41.8] versus 12.6 [6.9-22] mL; P<0.001), but it was strongly correlated with ICH volume (ρ=0.905; P<0.001). Patients who experienced significant hematoma expansion had higher absolute perihematomal edema volume (18.4 [10-34.6] versus 11.8 [6.5-22] mL; P<0.001) but similar relative perihematomal edema volume (1.09 [0.89-1.37] versus 1.12 [0.88-1.54]; P=0.400). Absolute perihematomal edema volume and poorer outcomes were higher by tertiles of ICH volume, and perihematomal edema volume did not independently predict significant hematoma expansion. Conclusions: Perihematomal edema volume is greater at baseline in the presence of a spot sign. However, it is strongly correlated with ICH volume and does not independently predict hematoma expansion.
    No preview · Article · Dec 2015 · Stroke
  • No preview · Article · Nov 2015 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
  • [Show abstract] [Hide abstract] ABSTRACT: Background and purpose: Nine- and 24-point prediction scores have recently been published to predict hematoma expansion (HE) in acute intracerebral hemorrhage. We sought to validate these scores and perform an independent analysis of HE predictors. Methods: We retrospectively studied 301 primary or anticoagulation-associated intracerebral hemorrhage patients presenting <6 hours post ictus prospectively enrolled in the Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus Computed Tomography (PREDICT) study. Patients underwent baseline computed tomography angiography and 24-hour noncontrast computed tomography follow-up for HE analysis. Discrimination and calibration of the 9- and 24-point scores was assessed. Independent predictors of HE were identified using multivariable regression and incorporated into the PREDICT A/B scores, which were then compared with existing scores. Results: The 9- and 24-point HE scores demonstrated acceptable discrimination for HE>6 mL or 33% and >6 mL, respectively (area under the curve of 0.706 and 0.755, respectively). The 24-point score demonstrated appropriate calibration in the PREDICT cohort (χ(2) statistic, 11.5; P=0.175), whereas the 9-point score demonstrated poor calibration (χ(2) statistic, 34.3; P<0.001). Independent HE predictors included spot sign number, time from onset, warfarin use or international normalized ratio >1.5, Glasgow Coma Scale, and National Institutes of Health Stroke Scale and were included in PREDICT A/B scores. PREDICT A showed improved discrimination compared with both existing scores, whereas performance of PREDICT B varied by definition of expansion. Conclusion: The 9- and 24-point expansion scores demonstrate acceptable discrimination in an independent multicenter cohort; however, calibration was suboptimal for the 9-point score. The PREDICT A score showed improved discrimination for HE prediction but requires independent validation.
    No preview · Article · Oct 2015 · Stroke
  • [Show abstract] [Hide abstract] ABSTRACT: Background and purpose: Hematoma expansion in intracerebral hemorrhage is associated with higher morbidity and mortality. The computed tomography (CT) angiographic spot sign is highly predictive of expansion, but other morphological features of intracerebral hemorrhage such as fluid levels, density heterogeneity, and margin irregularity may also predict expansion, particularly in centres where CT angiography is not readily available. Methods: Baseline noncontrast CT scans from patients enrolled in the Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT (PREDICT) study were assessed for the presence of fluid levels and degree of density heterogeneity and margin irregularity using previously validated scales. Presence and grade of these metrics were correlated with the presence of hematoma expansion as defined by the PREDICT study on 24-hour follow-up scan. Results: Three hundred eleven patients were included in the analysis. The presence of fluid levels and increasing heterogeneity and irregularity were associated with 24-hour hematoma expansion (P=0.021, 0.003 and 0.049, respectively) as well as increases in absolute hematoma size. Fluid levels had the highest positive predictive value (50%; 28%-71%), whereas margin irregularity had the highest negative predictive value (78%; 71%-85). Noncontrast metrics had comparable predictive values as spot sign for expansion when controlled for vitamin K, antiplatelet use, and baseline National Institutes of Health Stroke Scale, although in a combined area under the receiver-operating characteristic curve model, spot sign remained the most predictive. Conclusions: Fluid levels, density heterogeneity, and margin irregularity on noncontrast CT are associated with hematoma expansion at 24 hours. These markers may assist in prediction of outcomes in scenarios where CT angiography is not readily available and may be of future help in refining the predictive value of the CT angiography spot sign.
    No preview · Article · Oct 2015 · Stroke
  • No preview · Article · Oct 2015 · The Canadian journal of cardiology
  • [Show abstract] [Hide abstract] ABSTRACT: Objective: We derived and validated a method to screen all hospital admissions for 1° subarachnoid hemorrhage by retrospectively implementing recognized diagnostic criteria. Study design and setting: A screen for 1° subarachnoid hemorrhage was developed using two previously created registries. Screen-positive cases underwent diagnosis confirmation with primary record review. A review of all patient hospital encounters with the diagnostic code for 1° subarachnoid hemorrhage and cross-referencing with an existing subarachnoid hemorrhage registry was undertaken to identify missed cases. Results: Three sub-screens were combined to form the 1° subarachnoid hemorrhage screen (sensitivity: 98.4% [95% CI: 91.7-99.7%], specificity: 93.4% [95% CI: 90.4-95.4%], n=455 patients in validation sample). From 1699 screen-positive admissions between 1 July 2002 and 30 June 2011, we identified 831 true cases of subarachnoid hemorrhage of which 632 patients had 1° subarachnoid hemorrhage from ruptured aneurysm/AVM (sensitivity: 96.5% [95% CI: 94.8%-97.8%]; specificity: 40.3% [95% CI: 38.1%-42.6%]). A review of all encounters with a diagnostic code for 1° subarachnoid hemorrhage yielded an additional 22 true cases. Conclusion: When positive, our 1° subarachnoid hemorrhage screen significantly increases the probability of this diagnosis in a particular hospitalization. The addition of patient hospitalizations encoded with the diagnostic code for 1° subarachnoid hemorrhage improved sensitivity. Together, these methods represent the best way to retrospectively identify all cases of 1° subarachnoid hemorrhage within an extensive sampling frame.
    No preview · Article · Sep 2015 · Journal of clinical epidemiology
  • [Show abstract] [Hide abstract] ABSTRACT: There is a paucity of literature on early discharge after elective aneurysm treatment. We hypothesize that patient discharge on the next day is not associated with an increase in post-discharge adverse events. We retrospectively reviewed elective coiling procedures between 2009 and 2013. The primary outcome measure was 30-day adverse events (emergency department visits, readmission or prolonged admission >30 days, and death). We evaluated the association between early and standard discharge for the primary outcome using the Fisher exact test. We also assessed the association of the primary outcome with other patient and technical variables as well as findings on pre-discharge diffusion weighted imaging. We included 97 patients. Median length of hospital stay (LOS) was 2.52 days, and in 26 patients (26.8%) LOS was <2 days. There was no significant difference in post-discharge adverse outcome rates between early and standard discharge groups (19.2% vs 18.3%; p=1.000). The primary outcome was significantly associated with the use of flow diverters (p=0.0287) and change in modified Rankin Scale category at discharge (p=0.0329). No significant association was noted between the outcome and the other variables including the presence of diffusion restriction pre-discharge (p>0.05). Patient discharge the next day after elective intracranial aneurysm coiling is not associated with an increase in 30-day adverse outcomes. A prospective study investigating early discharge in elective treatment is warranted. OHSN-REB #20130786-01H. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    No preview · Article · Sep 2015 · Journal of Neurointerventional Surgery
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    [Show abstract] [Hide abstract] ABSTRACT: Background: Intracerebral hemorrhage (ICH) volume, spot sign, coagulation status and time of onset predict early hematoma expansion (HE). However, the role of ICH location on HE remains unclear. We hypothesized that lobar ICH facilitates HE as it provides a larger potential volume for expansion, as compared to deep locations. However, we also hypothesized that deep ICH will have a paradoxically increased risk of mortality and morbidity, due to the close proximity of critical structures and increased risk of ventricular rupture. Methods: We analyzed data from the prospective multicentre PREDICT study where patients with ICH presenting to hospital under 6 hours of symptom onset received a baseline CT, CTA, 24 hour follow-up CT, and 90-d mRS. We classified ICH location as lobar vs deep, and our primary outcomes were significant HE (>6 mL) and poor clinical outcome (mRS > 3). We used multivariable regression with stepwise selection to adjust for relevant covariates. Results: Among 302 patients meeting the inclusion criteria, lobar hemorrhage was associated with increased hematoma expansion >6 mL (p = 0.003), spot sign prevalence (p = 0.004), poor clinical outcome (p = 0.011), and mortality (p = 0.017). When adjusted for covariates, lobar location independently predicted significant hematoma expansion (aOR 2.3 [95% CI: 1.2–4.4], p = 0.02) and poor clinical outcome (aOR 2.8 [95% CI: 1.3–5.7], p = 0.006). Conclusions: Spontaneous lobar ICH is more likely to expand and leads to worse clinical outcome. Deep ICHs actually had a better prognosis, in spite of anatomical proximity to critical structures. Our findings confirm that baseline ICH location should be considered for risk stratification algorithms.
    Full-text · Article · Sep 2015 · International Journal of Stroke
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    Dataset: Figure 1
    Full-text · Dataset · Jul 2015
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    [Show abstract] [Hide abstract] ABSTRACT: The purpose of this article is to prospectively test the hypothesis that time-resolved CT angiography (TRCTA) on a Toshiba 320-slice CT scanner enables the same characterization of cerebral vascular malformation (CVM) including arteriovenous malformation (AVM), dural arteriovenous fistula (DAVF), pial arteriovenous fistula (PAVF) and developmental venous anomaly (DVA) compared to digital subtraction angiography (DSA). Eighteen (eight males, 10 females) consecutive patients (11 AVM, four DAVF, one PAVF, and two DVA) underwent 19 TRCTA (Aquillion one, Toshiba) for suspected CVM diagnosed on routine CT or MRI. One patient with a dural AVF underwent TRCTA and DSA twice before and after treatment. Of the 18 patients, 13 were followed with DSA (Artis, Siemens) within two months of TRCTA. Twenty-three sequential volume acquisitions of the whole head were acquired after injection of 50 ml contrast at the rate of 4 ml/sec. Two patients with DVA did not undergo DSA. Two TRCTA were not assessed because of technical problems.TRCTAs were independently reviewed by two neuroradiologists and DSA by two other neuroradiologists and graded according to the Spetzler-Martin classification, Borden classification, overall diagnostic quality, and level of confidence. Weighted kappa coefficients (k) were calculated to compare reader's assessment of DSA vs TRCTA. There was excellent (k = 0.83 and 1) to good (k = 0.56, 0.61, 0.65 and 0.67) agreement between the different possible pairs of neuroradiologists for the assessment of vascular malformations. TRCTA may be a sufficient noninvasive substitute for conventional DSA in certain clinical situations. © The Author(s) 2015.
    Full-text · Article · Jun 2015
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    [Show abstract] [Hide abstract] ABSTRACT: Despite the increasing use of stent-assisted coiling (SAC), data on its long-term clinical and angiographic results are limited. The objective of this article is to assess the long-term clinical and angiographic outcomes in SAC in our single-center practice. We conducted a retrospective analysis of intracranial aneurysms treated with detachable coils during the period 2003-2012. Patients were divided into SAC and non-SAC groups and were analyzed for aneurysm occlusion, major recurrence and clinical outcome. Logistic regression analyses identified factors associated with clinical/angiographic outcomes (p value <0.05 was statistically significant). A total of 516 procedures met inclusion criteria: Sixty-three (12.2%) patients underwent SAC, of whom 56 (89%) had an elective procedure whereas 286 (63.1%) aneurysms from the non-SAC group were ruptured. In the unruptured subcohort, baseline class I was achieved in 24 (38%, p = 0.91), and predischarge modified Rankin scale score (mRS) 0-2 was obtained in 96.4% of cases in the SAC group versus 90.4% in the non-stent group. The major recurrence was 9.5% versus 11.3% in the SAC and non-SAC group, respectively (p = 0.003). At last clinical assessment, 98.2% of the patients from the unruptured SAC group had mRS 0-2 (mean follow-up, 58 months) versus 93.6% (mean follow-up, 56 months) in the unruptured non-SAC group (p = 0.64). Periprocedural vasospasm was associated with long-term poor outcome in the unruptured SAC subcohort (p = 0.0008). SAC and non-SCA techniques show comparable safety and clinical outcome. The SAC technique significantly decreases retreatment rates. Periprocedural vasospasm resulting from vessel manipulation is associated with poor outcome in SAC of unruptured aneurysms. © The Author(s) 2015 Reprints and permissions:
    Full-text · Article · May 2015 · Interventional Neuroradiology
  • [Show abstract] [Hide abstract] ABSTRACT: Whole-slide scanning of tissue sections spatially informed by imaging studies offers the opportunity to reconstruct specimens for co-registration to 3D imaging data. Digital image analysis algorithms can be designed to analyze and reconstruct such specimens via electronic “pipelines”. Methods: A goal of the Canadian Atherosclerosis Imaging Network (CAIN) is to improve the assessment of carotid atheromatous disease through studies that inform clinical imaging with gold-standard data (plaque pathology). To achieve this, sectioned atheromas are manually annotated and analyzed by electronic algorithm for pathological features of interest. Resulting images are then reassembled in 3D for registration to ultrasound, CT, PET-CT and MRI studies. Results: Carotid endarterectomy specimens were sub-serially sectioned, stained, digitized and annotated manually and by electronic algorithms. Resulting 2D images were successfully rendered, reassembled and analyzed in 3D using ex-vivo micro-CT as a spatial reference. Furthermore, histology quantification using colour deconvolution was found to be preferred over hue-saturation-intensity methods 94.7-100% of the time in a blinded multiple rater study. Conclusion: Automated “pipelines” greatly facilitate 3D reconstruction in comparison to traditional slice-by-slice methods. Transformations spatially guided by pre-existing imaging data is not only faster, but has superior objectivity and fidelity. With embedded annotations, 3D pathology maps become a rich, micron-level, permanent digital pathological database for correlative studies.
    No preview · Article · May 2015 · The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques