Variation in CT perfusion protocol has implications on defining irreversibly damaged ischemic brain parenchyma

KEY POINTS

• Computed tomographic perfusion (CTP) is increasingly being used in the characterization of brain ischemia.• Variations in post-processing protocols continue to be a challenge, resulting in a slight variation of CTP results.• We need to adopt a universal acquisition protocol to help optimize output of CTP.

Imaging for Predicting Hemorrhagic Transformation of Acute Ischemic Stroke-A Narrative Review

Hemorrhagic transformation is caused by extravasation of blood products from vessels after acute ischemic stroke. It is an undesirable and potentially devastating complication, which occurs in 10%-40% of clinical cases. Hemorrhagic transformation is classified into four subtypes based on European cooperative acute stroke study II. Predicting hemorrhagic complications at presentation can be useful life saving/altering decisions for the patient. Also, understanding the mechanisms of hemorrhagic transformation can lead to new treatments and intervention measures. We highlighted various imaging techniques that have been used to predict hemorrhagic transformation. Specifically, we looked at the usefulness of perfusion and permeability imaging for hemorrhagic transformation. Use of imaging to predict hemorrhagic transformation could change patient management that may lead to the prevention of hemorrhagic transformation before it occurs. We concluded that the current evidence is not strong enough to rely on these imaging parameters for predicting hemorrhagic transformation and more studies are required.

Early diagnosis of mortality using admission CT perfusion in severe traumatic brain injury patients (ACT-TBI): protocol for a prospective cohort study

INTRODUCTION

Severe traumatic brain injury (TBI) is a catastrophic neurological condition with significant economic burden. Early in-hospital mortality (<48 hours) with severe TBI is estimated at 50%. Several clinical examinations exist to determine brain death; however, most are difficult to elicit in the acute setting in patients with severe TBI. Having a definitive assessment tool would help predict early in-hospital mortality in this population. CT perfusion (CTP) has shown promise diagnosing early in-hospital mortality in patients with severe TBI and other populations. The purpose of this study is to validate admission CTP features of brain death relative to the clinical examination outcome for characterizing early in-hospital mortality in patients with severe TBI.

METHODS AND ANALYSIS

The Early Diagnosis of Mortality using Admission CT Perfusion in Severe Traumatic Brain Injury Patients study, is a prospective cohort study in patients with severe TBI funded by a grant from the Canadian Institute of Health Research. Adults aged 18 or older, with evidence of a severe TBI (Glasgow Coma Scale score ≤8 before initial resuscitation) and, on mechanical ventilation at the time of imaging are eligible. Patients will undergo CTP at the time of first imaging on their hospital admission. Admission CTP compares with the reference standard of an accepted bedside clinical assessment for brainstem function. Deferred consent will be used. The primary outcome is a binary outcome of mortality (dead) or survival (not dead) in the first 48 hours of admission. The planned sample size for achieving a sensitivity of 75% and a specificity of 95% with a CI of ±5% is 200 patients.

ETHICS AND DISSEMINATION

This study has been approved by the University of Manitoba Health Research Ethics Board. The findings from our study will be disseminated through peer-reviewed journals and presentations at local rounds, national and international conferences. The public will be informed through forums at the end of the study.

TRIAL REGISTRATION NUMBER

NCT04318665.

Bleomycin for orbital and peri-orbital veno-lymphatic malformations - A systematic review

BACKGROUND

Orbital and peri-orbital venolymphatic malformations (VLM) are low flow vascular malformations. Intralesional bleomycin is now commonly being used to treat such malformations.

OBJECTIVE

The purpose of this systematic review is to synthesize evidence on the safety and efficacy of bleomycin/pingyangmycin sclerotherapy for the treatment of orbital and peri-orbital VLM.

METHODS

We searched Medline, Embase, Scopus and Cochrane database for studies reporting outcomes of bleomycin/pingyangmycin sclerotherapy for orbital and peri-orbital VLM between 1974 to April 5th, 2019. Nine retrospective cohort studies enrolling 132 patients were included. Two reviewers independently screened and extracted data and assessed the risk of bias. Predefined outcome measures were subjective and objective reduction of the lesion and associated complications.

RESULTS

Subjective reduction of the lesions was seen in 96.2% of the studies. Objective reduction of the lesion and symptomatic improvement were reported in 91.6 and 95% of the studies respectively. Non responders were 9.0%. Minor adverse events were reported in 18.1% of the studies. Major complications like pulmonary toxicity or pulmonary fibrosis was not encountered in any of the included studies. Quality of evidence was generally low.

CONCLUSION

Bleomycin/pingyangmycin sclerotherapy is very effective and relatively safe for the treatment of orbital and periorbital VLM and is not associated with any major side effects including pulmonary fibrosis.Limitations: The systematic review is limited mainly due to low quality of the included studies with retrospective design.

Comprehensive Aneurysm Management (CAM): An All-Inclusive Care Trial for Unruptured Intracranial Aneurysms

BACKGROUND

In the absence of randomized evidence, the optimal management of patients with unruptured intracranial aneurysms (UIA) remains uncertain.

METHODS

Comprehensive Aneurysm Management (CAM) is an all-inclusive care trial combined with a registry. Any patient with a UIA (no history of intracranial hemorrhage within the previous 30 days) can be recruited, and treatment allocation will follow an algorithm combining clinical judgment and randomization. Patients eligible for at least 2 management options will be randomly allocated 1:1 to conservative or curative treatment. Minimization will be used to balance risk factors, using aneurysm size (≥7 mm), location (anterior or posterior circulation), and age <60 years.

RESULTS

The CAM primary outcome is survival without neurologic dependency (modified Rankin Scale [mRS] score <3) at 10 years. Secondary outcome measures include the incidence of subarachnoid hemorrhage during follow-up and related morbidity and mortality; morbidity and mortality related to endovascular treatment or surgical treatment of the UIA at 1 year; overall morbidity and mortality at 1, 5, and 10 years; when relevant, duration of hospitalization; and, when relevant, discharge to a location other than home. The primary hypothesis for patients randomly allocated to at least 2 options, 1 of which is conservative management, is that active UIA treatment will reduce the 10-year combined neurologic morbidity and mortality (mRS score >2) from 24% to 16%. At least 961 patients recruited from at least 20 centers over 4 years will be needed for the randomized portion of the study.

CONCLUSIONS

Patients with unruptured intracranial aneurysms can be comprehensively managed within the context of an all-inclusive care trial.

Endovascular Thrombectomy for Stroke Effectiveness Study—An Audit From a Small Tertiary Care Center

Purpose:

Endovascular thrombectomy (EVT) treatment for acute ischemic stroke is now recommended as a standard of care. However, implementing EVT in routine clinical practice poses many challenges, even in countries with advanced health-care systems. The aim of the current study is to delineate if EVT at our institution is an effective treatment for acute ischemic stroke.

Methods:

All patients who underwent EVT at our institution between December 2011 and July 2017 were retrospectively assessed from our prospective registry. Clinical and imaging (including the Alberta Stroke Program Early CT [ASPECT] score, single-phase computed tomography angiography, and computed tomography perfusion) criteria were utilized to determine EVT suitability. Primary outcomes included modified Rankin score (mRS) at 90 days and recanalization determined by the modified Treatment in Cerebral Infarction score. Effectiveness was assessed by comparing our cohort with patients receiving EVT in the ESCAPE (Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke) trial.

Results:

Eighty-eight patients presented to our hospital after a median of 87 minutes last seen normal. Of these, median ASPECT score was 9. A majority (72%) also received intravenous alteplase. Successful recanalization (≥TICI 2b) was achieved in 79%. At 90 days, 48% (36/75) were functionally independent (mRS score of 0-2) and 28% (21/75) were disabled (mRS score of 3-5); 24% (18/75) died (mRS of 6) within 90 days.

Conclusions:

An audit of our initial experience with EVT for the treatment of acute ischemic stroke in a small tertiary care center yielded similar results compared to the ESCAPE trial, which is encouraging for implementing this treatment in routine clinical practice.

Does Increasing Packing Density Using Larger Caliber Coils Improve Angiographic Results of Embolization of Intracranial Aneurysms at 1 Year: A Randomized Trial

BACKGROUND AND PURPOSE

The impact of increased aneurysm packing density on angiographic outcomes has not been studied in a randomized trial. We sought to determine the potential for larger caliber coils to achieve higher packing densities and to improve the angiographic results of embolization of intracranial aneurysms at 1 year.

MATERIALS AND METHODS

Does Embolization with Larger Coils Lead to Better Treatment of Aneurysms (DELTA) was an investigator-initiated multicenter prospective, parallel, randomized, controlled clinical trial. Patients had 4- to 12-mm unruptured aneurysms. Treatment allocation to either 15- (experimental) or 10-caliber coils (control group) was randomized 1:1 using a Web-based platform. The primary efficacy outcome was a major recurrence or a residual aneurysm at follow-up angiography at 12 ± 2 months adjudicated by an independent core lab blinded to the treatment allocation. Secondary outcomes included indices of treatment success and standard safety outcomes. Recruitment of 564 patients was judged necessary to show a decrease in poor outcomes from 33% to 20% with 15-caliber coils.

RESULTS

Funding was interrupted and the trial was stopped after 210 patients were recruited between November 2013 and June 2017. On an intent-to-treat analysis, the primary outcome was reached in 37 patients allocated to 15-caliber coils and 36 patients allocated to 10-caliber coils (OR = 0.931; 95% CI, 0.528-1.644; P = .885). Safety and other clinical outcomes were similar. The 15-caliber coil group had a higher mean packing density (37.0% versus 26.9%, P = .0001). Packing density had no effect on the primary outcome when adjusted for initial angiographic results (OR = 1.001; 95% CI, 0.981-1.022; P = .879).

CONCLUSIONS

Coiling of aneurysms randomized to 15-caliber coils achieved higher packing densities compared with 10-caliber coils, but this had no impact on the angiographic outcomes at 1 year, which were primarily driven by aneurysm size and initial angiographic results.

Clinico-radiological correlation of magnetic resonance imaging findings in patients with idiopathic intracranial hypertension

PURPOSE

Although several studies have reported imaging findings associated with idiopathic intracranial hypertension (IIH), less is known about the correlation between imaging findings and IIH-related symptoms or signs. Our study aimed to determine if clinical features of IIH are correlated with magnetic resonance imaging (MRI) features.

METHODS

A retrospective chart review was conducted on consecutive patients presenting at the neuro-ophthalmology department over the last 15 years. All patients diagnosed with IIH were identified and those with available MRI were included in the final analysis. All MRI images were reviewed by a neuroradiologist blinded to the presenting symptoms and signs. Statistical analysis was performed to determine the correlation between the MRI findings with each clinical symptom or sign.

RESULTS

Thirty-one out of 88 patients with the initial diagnosis of IIH had MRI available and were included in the study. Significant correlations were observed between colour vision and amount of perineural fluid around the optic nerve on MRI (r = - 0.382; p = 0.004), disc assessment and intraocular optic nerve protrusion (r = 0.364; p = 0.004), disc assessment and perineural fluid around the optic nerve (r = 0.276; p = 0.033) and disc assessment and venous sinus stenosis (r = 0.351; p = 0.009).

CONCLUSION

Our study highlights correlations between imaging and clinical findings of IIH. MRI findings in IIH may be useful in ruling out ominous causes of intracranial pressure and risk stratifying ophthalmologic intervention and management of patients with headaches possibly due to IIH.

Are Anterior Communicating Aneurysms Truly Anterior Communicating Aneurysms? An Observational Study

OBJECTIVE

The term anterior communicating (ACom) aneurysm is often broadly used to classify any aneurysm formed on the A1-A2 junction, A1, A2, or ACom arteries. Aneurysm location has been associated with rupture risk, so whether an aneurysm is truly formed on the ACom artery can critically affect treatment decisions. The aim of this study was to reclassify broadly termed ACom aneurysms into 4 subgroups (A1, A2, true ACom, and A1-A2 junction) based on their location.

METHODS

A retrospective, pilot study was conducted to identify all consecutive patients with ACom aneurysm managed over the past 4 years in a single center. Using computed tomography angiography, aneurysms were classified into 1 of the 4 subgroups. Additional information was collected on patient demographics, subarachnoid hemorrhages, projections of aneurysm dome, and aneurysm diameter.

RESULTS

A total of 48 aneurysms with available computed tomography angiography imaging were included in the final analysis. The reclassification of ACom aneurysms into subgroups resulted in 40 A1-A2 junction, 6 true ACom, 2 A2, and zero A1 aneurysms. A total of 100% versus 80% of true ACom and A1-A2 junction aneurysms ruptured, respectively. All elective coiling procedures were performed on unruptured A1-A2 junction aneurysms.

CONCLUSIONS

We found only 13% of the aneurysms initially referred to as ACom to be true ACom aneurysms. A more nuanced approach to ACom aneurysm classification may better guide management strategies.

The Role of Neuroimaging in the Determination of Brain Death

BACKGROUND AND PURPOSE

Brain death determination (BDD) is primarily a clinical diagnosis, where death is defined as the permanent loss of brainstem function. In scenarios where clinical examinations are inaccurate, ancillary imaging tests are required. The choice of ancillary imaging test is variable, but the common denominator for all of them is to establish a lack of cerebral blood flow. The purpose of this study was to compare the diagnostic accuracy and interrater reliability of different ancillary imaging tests used for BDD.

METHODS

Archival data were retrospectively analyzed for all patients who underwent any ancillary imaging test for BDD at our institution. The results of ancillary imaging tests were compared with, the reference standard, the clinical checklist for declaration of brain death. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of different ancillary imaging tests for BDD were performed. Interobserver agreement between two observers was measured using kappa statistics for each of the imaging modalities.

RESULTS

A total of 74 patients underwent 41 computer tomography perfusion (CTP), 54 CT angiogram, 15 radionuclide scans, 1 cerebral angiogram, 3 magnetic resonance imaging, and 71 nonenhanced CT (NECT) head for BDD. All ancillary tests (except NECT head) showed 100% specificity and PPV. CTP had the highest sensitivity and NPV. All ancillary imaging tests demonstrated very high interrater reliability.

CONCLUSIONS

The uses of ancillary imaging tests for BDD are increasing. Within this study's limitations, CTP followed by radionuclide scan were found to be the most accurate and reliable ancillary imaging test for BDD.

Computed Tomography Perfusion Aids in the Prognostication of Comatose Postcardiac Arrest Patients

Early assessment of the potential for neurologic recovery in comatose cardiac arrest patients (CCAP) has been a challenge despite significant evolution in management and imaging techniques. The purpose of study was to determine if the use of computed tomography perfusion (CTP) in CCAPs is feasible and if this technique can predict the likelihood that CCAPs will have a devastating outcome at hospital discharge. We prospectively enrolled 10 newly admitted comatose adults who had an out-of-hospital cardiac arrest and were treated with standard therapeutic hypothermia protocols. Patients underwent CTP of the head within 6 hours after finishing therapeutic hypothermia treatment. The imaging findings were compared with the results of a clinical assessment, as well as the modified Rankin Scale (mRS) score at hospital discharge. Sensitivity, specificity, and positive and negative predictive values for CTP were calculated to predict clinical outcome. Eight patients had an mRS score of ≥5, and 2 patients had an mRS score of ≤2 at hospital discharge. CTP predicted a good clinical outcome in both patients with an mRS score of ≤2. The area under the curve (AUC) for plain computed tomography of the head, computerized tomography angiogram 4-point scale, computerized tomography angiogram 7-point scale, CTP of the whole brain, and CTP of the brainstem for predicting the results of the immediate clinical assessment were 0.76, 0.83, 0.67, 0.83, and 1.0, respectively. The AUCs for predicting outcome at discharge were 0.69, 0.63, 0.56, 0.63, 0.63, and 0.69, respectively. In conclusion, our pilot study showed that CTP is feasible and had a very high AUC for predicting the results of immediate clinical assessment in CCAP.

Digital Subtraction Angiography-Dynavision in Pretreatment Planning for Embolization of Dural Arterio-Venous Fistulas

BACKGROUND AND PURPOSE

We have found DSA-Dynavision with multiplanar reconstruction very helpful in understanding the complex anatomy and planning of treatment of carotico-cavernous fistulas. The purpose of our study was to examine whether using DSA-Dynavision in pretreatment planning results in better outcome after endovascular treatment of dural arterio-venous fistulas (dAVFs).

METHODS

Patients with dAVF treated with endovascular embolization were retrospectively identified from our interventional neuroradiology database. Patients were assessed and divided into those with DSA-Dynavision and those without. They were compared for procedural time, angiographic evidence of cure, rates of resolution of cortical venous reflux (CVR), complications, and need for postembolization surgery.

RESULTS

Eighty-six percent of 28 patients (mean age 57 years, range 1.67-84 years) had Borden type 3 DAVF; 7% had Borden type 2; and 7% had Borden type 1. DSA-Dynavision was used in 14 of 28 (50%) patients. Fewer patients with DSA-Dynavision required postendovascular embolization surgery (7% vs. 50%, P = .01) and fewer DSA-Dynavision patients had CVR postprocedure (29% vs. 71%, P = .023). Mean procedural time (207 vs. 249 minutes; P = .40); permanent neurological complication rates (7% vs. 7%, P = 1.0); rate of immediate angiographic occlusion (64% vs. 29%, P = .061), and reported resolution of symptoms (79% vs. 53%, P = .18) were not significantly different. There was no significant difference in follow-up (mean: 75 vs 120 weeks, P = .47).

CONCLUSION

The use of DSA-Dynavision in planning of endovascular treatment of dAVF is associated with higher rates of elimination of CVR and less need for postembolization surgery.

Use of Noncontrast Computed Tomography and Computed Tomographic Perfusion in Predicting Intracerebral Hemorrhage After Intravenous Alteplase Therapy

Background and Purpose—

Intracerebral hemorrhage is a feared complication of intravenous alteplase therapy in patients with acute ischemic stroke. We explore the use of multimodal computed tomography in predicting this complication.

Methods—

All patients were administered intravenous alteplase with/without intra-arterial therapy. An age- and sex-matched case–control design with classic and conditional logistic regression techniques was chosen for analyses. Outcome was parenchymal hemorrhage on 24- to 48-hour imaging. Exposure variables were imaging (noncontrast computed tomography hypoattenuation degree, relative volume of very low cerebral blood volume, relative volume of cerebral blood flow ≤7 mL/min·per 100 g, relative volume of T max ≥16 s with all volumes standardized to z axis coverage, mean permeability surface area product values within T max ≥8 s volume, and mean permeability surface area product values within ipsilesional hemisphere) and clinical variables (NIHSS [National Institutes of Health Stroke Scale], onset to imaging time, baseline systolic blood pressure, blood glucose, serum creatinine, treatment type, and reperfusion status).

Results—

One-hundred eighteen subjects (22 patients with parenchymal hemorrhage versus 96 without, median baseline NIHSS score of 15) were included in the final analysis. In multivariable regression, noncontrast computed tomography hypoattenuation grade ( P <0.006) and computerized tomography perfusion white matter relative volume of very low cerebral blood volume ( P =0.04) were the only significant variables associated with parenchymal hemorrhage on follow-up imaging (area under the curve, 0.73; 95% confidence interval, 0.63–0.83). Interrater reliability for noncontrast computed tomography hypoattenuation grade was moderate (κ=0.6).

Conclusions—

Baseline hypoattenuation on noncontrast computed tomography and very low cerebral blood volume on computerized tomography perfusion are associated with development of parenchymal hemorrhage in patients with acute ischemic stroke receiving intravenous alteplase.

Regional Comparison of Multiphase Computed Tomographic Angiography and Computed Tomographic Perfusion for Prediction of Tissue Fate in Ischemic Stroke

BACKGROUND AND PURPOSE

Within different brain regions, we determine the comparative value of multiphase computed tomographic angiography (mCTA) and computed tomographic perfusion (CTP) in predicting follow-up infarction.

METHODS

Patients with M1-middle cerebral artery occlusions were prospectively included in this multicenter study. Regional analysis was performed for each patient within Alberta Stroke Program Early CT Score regions M2 to M6. Regional pial vessel filling was assessed on mCTA in 3 ways: (1) Washout of contrast within pial vessels; (2) Extent of maximal pial vessel enhancement compared with contralateral hemisphere; (3) Delay in maximal pial vessel enhancement compared with contralateral hemisphere. Cerebral blood flow, cerebral blood volume, and Tmax data were extracted within these Alberta Stroke Program Early CT Score regions. Twenty-four- to 36-hour magnetic resonance imaging/CT was assessed for infarct in each Alberta Stroke Program Early CT Score region (defined as >20% infarction within that region). Mixed effects logistic regression models were used to compare mCTA and CTP parameters when predicting brain infarction. Area under the receiver operating characteristics was used to assess discriminative value of statistical models.

RESULTS

Seventy-seven patients were included. mCTA parameter washout and CTP parameter Tmax were significantly associated with follow-up infarction in all models (P<0.05). The area under the receiver operating characteristic for mCTA models ranged from 92% to 94% and was not different compared with all CTP models (P>0.05). Mean Tmax and cerebral blood volume values were significantly different between each washout score (P<0.01) and each delay score category (P<0.01). Mean Tmax, cerebral blood flow, and cerebral blood volume values were significantly different between each extent score category (P<0.05).

CONCLUSIONS

Similar to CTP, multiphase CTA can be used to predict tissue fate regionally in acute ischemic stroke patients.

DSA-Dynavision in pretreatment planning for coil embolization of indirect carotid-cavernous fistula

INTRODUCTION

Indirect carotid cavernous fistulas are treated with coil embolization when they present with orbital/visual symptoms or if there is cortical venous reflux. Most of the time, the treatment is done by non-specifically packing the whole cavernous sinus with coils. The purpose of this case series was to examine whether DSA-Dynavision before embolization would improve treatment by shortening the procedure time, requiring fewer coils, or reducing the complication rate.

MATERIALS AND METHOD

8 patients with 9 fistula sites were retrospectively identified. DSA-Dynavision and non-DSA-Dynavision patients were compared in a retrospective cohort study.

RESULTS

Mean total coil length was significantly shorter for the group who had DSA-Dynavision than for those who had non-DSA-Dynavision (130.5 cm vs 190 cm, p=0.034) and mean procedural time was significantly shorter for the DSA-Dynavision group (171.1 min vs 280.3 min, p=0.025). A transient neurological complication was seen in only one patient.

CONCLUSIONS

The use of DSA-Dynavision in pre-procedural planning facilitates selective coil embolization of the foot of the vein.

Canadian Registry of LVIS Jr for Treatment of Intracranial Aneurysms (CaRLA)

INTRODUCTION

Stents reduce the rate of angiographic recurrence of intracranial aneurysms. The newest stent for intracranial use is the Low-profile Visible Intraluminal Support device (LVIS Jr).

OBJECTIVE

To assess the efficacy of the new stent in a multicenter retrospective registry.

MATERIALS AND METHOD

Centers across Canada using LVIS Jr were contacted and asked to participate in a retrospective registry of consecutive patients treated with LVIS Jr for intracranial aneurysms between January 2013 and July 2015.

RESULTS

A total of 102 patients, with saccular aneurysms in 100 patients (72 women; age range 21-78 years; mean 56.0 years; median 57.5 years) were treated with a LVIS Jr stent. The mean maximum diameter of the dome and neck of the aneurysm and dome to neck ratios were 8.3 mm±7.7 mm, 4.4 mm±1.9 mm, and 1.86±1.22, respectively. Angiographic complications arose in 23 patients, clinical complications in 9 patients, and only 3% of permanent neurological deficits occurred. Death occurred in 1 patient, unrelated to the stent. The ruptured status of the aneurysms (OR=3.29; p=0.046) and use of LVIS Jr for bailout (OR=2.54; p=0.053) showed a trend towards significant association with higher angiographic complications. At the last available follow-up, 68 class I, 20 class II, and 12 class III results were seen.

CONCLUSIONS

The LVIS Jr stent is a safe and effective device for stent-assisted coiling, with 3% permanent neurological complications. Stent-assisted coiling continues to be technically challenging in cases of ruptured aneurysms and bailout situations.

Does computed tomography permeability predict hemorrhagic transformation after ischemic stroke?

AIM: To use perfusion-derived permeability-surface area product maps to predict hemorrhagic transformation following thrombolytic treatment for acute ischemic stroke.

METHODS: We retrospectively analyzed our prospectively kept acute stroke database over five consecutive months for patients with symptoms of acute ischemic stroke (AIS) who had computed tomography (CT) perfusion (CTP) done at arrival. Patients included in the analyses also had to have a follow-up CT. The permeability-surface area product maps (PS) was calculated for the side of the ischemia and/or infarction and for the contralateral unaffected side at the same level. The cerebral blood flow map was used to delineate the ischemic territory. Next, a region of interest was drawn at the centre of this territory on the PS parametric map. Finally, a mirror region of interest was created on the contralateral side at the same level. The relative permeability-surface area product maps (rPS) provided an internal control and was calculated as the ratio of the PS on the side of the AIS to the PS on the contralateral side. A student t-test was performed after log conversion of rPS between patients with and without hemorrhagic transformation. Log conversion was used to convert the data into normal distribution to use t-test. For the group of patients who experienced intracranial bleed, a student t-test was performed between those with only petechial hemorrhage and those with more severe parenchymal hematoma with subarachnoid haemorrhage.

RESULTS: Of 84 patients with AIS and CTP at admission, only 42 patients had a follow-up CT. The rPS derived using the normal side as the internal control was significantly higher (P = 0.003) for the 15 cases of hemorrhagic transformation (1.71 + 1.64) compared to 27 cases that did not have any (1.07 + 1.30). Patients with values above the overall mean rPS of 1.3 had an increased likelihood of subsequent hemorrhagic transformation. The sensitivity of using this score to predict hemorrhagic transformation was 71.4, the specificity was 78.6, with a positive predictive value of 62.5 and negative predictive value of 84.6. The accuracy was 76.2. The odds ratio of an event occurring with such an rPS was 9.2. Of the 15 cases of hemorrhagic transformation, there was no difference (P = 0.35) in the rPS between the eight cases of petechial and the seven cases of more severe hemorrhagic events.

CONCLUSION: Pretreatment PS can predict the occurrence of hemorrhagic transformation on follow-up of AIS patients with relatively high sensitivity, specificity, positive and negative predictive value.

CT Perfusion in Acute Stroke: "Black Holes" on Time-to-Peak Image Maps Indicate Unsalvageable Brain

BACKGROUND AND PURPOSE

CT perfusion is becoming important in acute stroke imaging to determine optimal patient-management strategies. The purpose of this study was to examine the predictive value of time-to-peak image maps and, specifically, a phenomenon coined a "black hole" for assessing infarcted brain tissue at the time of scan.

METHODS

Acute stroke patients were screened for the presence of black holes and their follow-up imaging (noncontrast CT or MR) was reviewed to assess for infarcted brain tissue.

RESULTS

Of the 23 patients with signs of acute ischemia on CT perfusion, all had black holes. The black holes corresponded with areas of infarcted brain on follow-up imaging (specificity 100%). Black holes demonstrated significantly lower cerebral blood volumes (P < .001) and cerebral blood flow (P < .001) compared to immediately adjacent tissue.

CONCLUSIONS

Black holes on time-to-peak image maps represent areas of unsalvageable brain.

Developing an in situ forming polyphosphate coacervate as a new liquid embolic agent: From experimental design to pilot animal study

A radiopaque temporary liquid embolic agent was synthesized from polyphosphate (PP) coacervates and optimized using a design of experiments approach. Variables studied were: strontium substitution (0-15 mol%), barium substitution (0-15 mol%), PP concentration and degree of polymerization of the polyphosphate (Dp). The viscosity, radiopacity and cell viability of the resulting coacervates were measured for 60 formulations and response surface modeling was used to determine the optimum coacervate that maximized radiopacity and cell viability. The optimum coacervate made from PP with a large Dp (9.5 g NaPP/100mL, 2.2 mol% Sr, 9 mol% Ba and 3.8 mol% Ca) was taken forward to a pilot animal trial. In this rabbit model, PP embolic agent successfully occluded the central auricular artery with promising biocompatibility. Further study is required to optimize the cohesiveness and clinical effectiveness of PP as an in situ setting temporary embolic agent.

STATEMENT OF SIGNIFICANCE

This article describes the development of a new radiopaque temporary liquid embolic agent from the optimization using design of experiments to a pilot animal study. Embolization is a minimally invasive interventional radiology procedure used to block blood flow in a targeted blood vessel. This procedure is used to treat many conditions including: tumors, aneurysms and arteriovenous malformations. Currently, no inherent radiopaque embolic agents are available in the clinic, which would allow for direct imaging of the material during the procedure and follow up treatment.

LVIS Jr 'shelf' technique: an alternative to Y stent-assisted aneurysm coiling

Wide-necked bifurcation intracranial aneurysms have traditionally not been amenable to coil embolization with the use of a single stent due to the high risk of coil prolapse. Y-configuration double stent-assisted coil embolization ('Y-stenting') of this aneurysm type has been shown to have generally good clinical outcomes, although the technique is complex with various challenges described in the literature. The compliant and flexible closed-cell design of braided stents such as the LVIS Jr allows for the creation of a 'shelf' across the aneurysm neck sufficient to prevent coil prolapse. We describe this novel 'shelf' technique and present a small case series of LVIS Jr stent-assisted wide-necked bifurcation intracranial aneurysm coiling in eight patients. Our small, albeit important, case series demonstrates that the 'shelf' technique is feasible and safe with very good short-term clinical and angiographic outcomes, and may obviate the need for Y-stenting.

Onyx versus nBCA and coils in the treatment of intracranial dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Intracranial dural arteriovenous fistulas (DAVFs) with cortical venous drainage have significant morbidity and mortality. Complete closure of these lesions is necessary to reduce these risks. The purpose of our study was to compare the outcome of DAVFs treated with Onyx versus those treated with n-Butyl Cyanoacrylate (nBCA) and coil embolization in a case-control study. Compared with nBCA and coil embolization, we hypothesized that Onyx embolization for DAVF is safer and has a higher chance of complete obliteration, with no need for post-embolization surgery for the DAVF.

MATERIALS AND METHODS

From 1998 to 2015, 29 patients who had DAVFs were treated with endovascular embolization. Of these, 24 patients had imaging available for analysis. Successful closure rates, complications, and procedure time were compared between the embolization techniques.

RESULTS

The chance of not requiring post-embolization surgery with Onyx (81.8%) was significantly higher (p = 0.005) than with nBCA (22.22%). The complication rate with Onyx (9.1%) tended to be lower compared with that of nBCA (22.22%; p = 0.37). Procedural time was not significantly different between Onyx (mean 267 minutes) and nBCA (mean 288 minutes) (p = 0.59). The odds ratio of a DAVF being treated with Onyx and then requiring no follow-up surgery was 17.5 (95% CI 1.97-155.4).

CONCLUSION

Our case-control study suggests that Onyx embolization is superior to nBCA and coil embolization in completely obliterating DAVFs, with higher odds of no post-embolization surgery. We also found that Onyx is safe for embolization of DAVFs, with no associated neurological mortality and morbidity.

Cerebral vascular malformations: Time-resolved CT angiography compared to DSA

PURPOSE

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).

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

TRCTA may be a sufficient noninvasive substitute for conventional DSA in certain clinical situations.

Amplatzer vascular plug for rapid vessel occlusion in interventional neuroradiology

The purpose of this paper is to report different uses of endovascular Amplatzer vascular plug (AVP) treatment for rapid vessel occlusion in the field of interventional neuroradiology. We retrospectively reviewed our interventional neuroradiology database from November 2010 to July 2015 and found nine patients who were treated with endovascular AVP. AVP was used for rapid vessel occlusion of common carotid artery (1 patient), internal carotid artery (5 patients), vertebral artery (2 patients), and internal jugular vein (1 patient). A median of three AVPs were used with almost immediate occlusion and no thromboembolic complications. Use of AVP is feasible, safe, rapid, and potentially cost-effective method for rapid occlusion of larger size vessels in the head and neck region for different indications.

SILK flow diverter for complex intracranial aneurysms: a Canadian registry

INTRODUCTION

The SILK flow diverter (SFD) is used for the treatment of complex intracranial aneurysms. Small case series have been reported in the literature but few studies with a large number of patients have been published. We present our experience with the SFD for the treatment of intracranial aneurysms in Canada.

METHODS

Centers across Canada using SFDs were contacted to fill out a case report form for patients treated with an SFD in their center. Individual centers were responsible for approval from their ethics committee. Image analysis was performed by individual operators. The case report forms were collected and the final analysis was performed.

RESULTS

A total of 92 patients were treated with SFDs in eight centers in Canada between January 2009 and August 2013. The aneurysms were located in the posterior circulation in 16 patients and in the anterior circulation in 76 patients. Most aneurysms (75%) were saccular in shape; 22% were fusiform and 3% were blister aneurysms. The size of the aneurysms varied from 2 to 60 mm with the neck varying from 2 to 60 mm. Perioperative morbidity and mortality were 8.7% and 2.2%, respectively. At the last available follow-up, 83.1% of the aneurysms were either completely or near-completely occluded. The rate of complications was higher for fusiform aneurysms (p<0.001).

CONCLUSIONS

The SFD appears to be an important tool for the treatment of complex intracranial aneurysms. Treatment outcomes and complication rates remain a problem, but should be considered in the context of available alternative interventions. Ongoing analysis of flow-diverting stents for radiographic and clinical performance is required.

Spinal dural arteriovenous fistula: correlation between radiological and clinical findings

Object

The pathophysiology of spinal dural arteriovenous fistulas (SDAVFs) results in perimedullary venous congestion and in turn central cord congestion. Clinically, this presents with progressive neurological dysfunctions that, if diagnosed in a timely fashion, can be at least halted and in part reversed.

In SDAVFs, imaging features on MRI and digital subtraction angiography (DSA) have not been studied in conjunction with clinical findings. The primary purpose of the present study was to test if severity of clinical presentation varies in relation to imaging.

Methods

This retrospective cohort study identified 12 patients treated for SDAVF at the authors' institution. The extent of venous congestion and cord edema was quantified by the number of vertebral levels shown to be affected on DSA and MRI. A modified Aminoff-Logue Scale (ALS) score was assigned at the time of diagnosis and again after definitive therapy. The patients were divided into one of two groups: those with venous congestion < 7 and ≥ 7 vertebral levels seen on DSA and MRI and with central cord edema < 6 and ≥ 6 levels. A t-test was used to assess for a difference in the presenting ALS score between the groups.

Results

Patients with ≥ 7 levels of venous congestion reported greater functional disability (DSA: p ≤ 0.001, Cohen's d = 0.509; and MRI: p ≤ 0.001, d = 0.632). Patients with a greater extent of cord edema also reported worse functional disability (p ≤ 0.001, d = 2.31). There was a strong linear correlation between the post- and pretreatment ALS scores (R2 = 0.86) for those with successful interventions (n = 9).

Conclusions

In patients with an SDAVF, the severity of the neurological dysfunction may be predicted by the extent of DSA- and MRI-documented venous congestion and cord edema. There was a strong positive relationship between initial and posttreatment neurological dysfunction.

CT perfusion for confirmation of brain death

SUMMARY

For pronouncing brain death, unlike CTP, the 2-phase CTA gives no functional information and is limited by inadvertent delay of the second acquisition, which may give false-negative results. The purpose of our study was to compare CTP and CTA derived from the CTP data with the Dupas and Frampas criteria for confirmation of brain death. A retrospective review of CTP in 11 consecutive patients for confirmation of brain death showed a sensitivity of 72.7% for 7- and 4-point scores, 81.8% for opacification of the ICV, and 100% for CTP scores in the brain stem. CTA obtained from the CTP data showed similar sensitivity in the diagnosis of brain death. This protocol also reduces the iodinated contrast dose and is less operator-dependent. The addition of the functional tools of CTP increased the sensitivity of CTA in the confirmation of brain death.

Angioarchitecture of brain AVM determines the presentation with seizures: proposed scoring system

BACKGROUND AND PURPOSE

Seizures are a common presentation in patients with brain arteriovenous malformations, but the pathogenesis of seizures remains poorly understood. The purpose of our study was to analyze various morphologic and hemodynamic characteristics of unruptured BAVMs presenting primarily with seizures and, on the basis of these, to propose a scoring system to predict seizures in patients with BAVMs.

MATERIALS AND METHODS

In a retrospective review of our BAVM data base from 2000 to 2009, after excluding patients with ruptured BAVMs, we classified patients into 2 groups, those with and without seizures at presentation. Clinical, angiographic, and hemodynamic characteristics on cerebral angiograms of all these patients were studied. The association between various angioarchitectural variables and seizure presentation was examined, and these results were used to guide the development of criteria to predict presentation with seizures.

RESULTS

Of 1299 patients in our data base, we finally analyzed 33 patients with unruptured BAVMs with seizures and 45 patients with unruptured AVMs without seizures. Location, fistulous component in the nidus, venous outflow stenosis, and the presence of a long pial course of the draining vein were identified as the strongest predictors of seizures. The proposed scoring system had good predictability of presentation with seizures.

CONCLUSIONS

Specific angioarchitectural characteristics of unruptured BAVMs may predict occurrence of seizures and may help in targeted treatment.

Whole brain CT perfusion on a 320-slice CT scanner

Computed tomography perfusion (CTP) has been criticized for limited brain coverage. This may result in inadequate coverage of the lesion, inadequate arterial input function, or omission of the lesion within the target perfusion volume. The availability of 320-slice CT scanners offers whole brain coverage. This minimizes the chances of misregistration of lesions regardless of location, and makes the selection of the arterial input function easy. We present different clinical scenarios in which whole brain CTP is especially useful.

Altered processing of visual memory in patients with mesial temporal sclerosis: an FMRI study

INTRODUCTION

Hippocampal complex and neocortex play distinct, complementary roles in processing of memory, which is impaired in patients with mesial temporal sclerosis (MTS).

METHOD

Ten right-sided MTS patients and 10 controls were prospectively assessed by functional Magnetic Resonance Imaging (fMRI) using encoding and retrieval of visual memory tasks. Image analyses were done using SPM2 and voxels showing activity with T-score>4 were considered significant. Two-sample t-test was applied for equality of means and P<.01 was considered significant. Patterns of activity in both encoding and retrieval tasks were compared between the patients and controls.

RESULTS

In normal controls, there was activation of bilateral tail of hippocampus, parahippocampal gyrus, occipital (right>left), right prefrontal, and inferior frontal region (T-score>9) during the encoding of memory and during the retrieval, there was activation of left inferior frontal region, bilateral parahippocampal gyrus, and occipital and parietal region (right>left) activity (T-score>4). In patients there was activation of bilateral prefrontal (left≫right), bilateral inferior parietal lobule (right≫left), and bilateral parieto-occipital lobe activity(T-score>4) during encoding and there was comparatively less activation (T-score>3) of bilateral inferior parietal lobule (left≫right) and bilateral prefrontal (right≫left) regions during retrieval.

CONCLUSION

Visual memory processing is affected and altered in patients with MTS. Reallocation of visual memory processing is observed in patients with MTS suggesting different networking.

Multiple spinal and cranial dural arteriovenous fistulas

Synchronous multiplicity of cranial and spinal dural arteriovenous fistulas (DAVFs) is known but uncommon. The authors report on a patient with the unusual finding of multiple cranial and multiple separate spinal DAVFs. The patient initially presented with vague visual symptoms in 2004. A cranial DAVF was identified along the left transverse sinus with cortical venous reflux and another DAVF was identified along the posterior part of the superior sagittal sinus with no cortical venous reflux. The first DAVF was treated both endovascularly and surgically and the second was left untreated. The follow-up angiogram showed multiple spinal DAVFs at the levels of C-1, C-2, and C-6 on the left side and at the C-3 level on the right side along with another cranial DAVF along the anterior part of the superior sagittal sinus with cortical venous reflux. A retrospective analysis of the digital subtraction angiogram and MR images suggested that the cervical spinal DAVFs were already present in 2004 (6 years previously). Multiple DAVFs, although rare, do exist and it is important to look for any evidence of their presence when evaluating patients with symptoms suggestive of arteriovenous fistulas.

Amplatzer vascular plug for occlusion of parent artery in carotid blowout with active extravasation

Carotid blowout is a devastating complication in patients with head and neck malignancy. Various treatments including high risk surgery, carotid stenting or carotid occlusion using either coils or detachable balloons have been described. The key for any treatment is the rapidity at which it can be performed. We describe treatment of common carotid blowout secondary to neoplastic infiltration using four Amplatzer vascular plugs deployed in less than ten minutes.

Long-term prospective follow-up of intracranial aneurysms treated with endovascular coiling using contrast-enhanced MR angiography

BACKGROUND AND PURPOSE

Catheter angiography has been the criterion standard for follow-up evaluation of coiled intracranial aneurysms. In our center, CE-MRA has been used to evaluate aneurysm recanalization. Our aim was to investigate the feasibility and usefulness of a CE-MRA protocol for following patients with intracranial aneurysms treated with endovascular coiling.

MATERIALS AND METHODS

From September 2003 to December 2006, 134 aneurysms were treated by endovascular coiling in 124 patients by using detachable coils. These patients were followed with CE-MRA at 3 months, 15 months, and 3 and 5 years. MRAs were analyzed by 2 interventional neuroradiologists. Findings were assigned to 3 categories: complete obliteration (class 1), residual neck (class 2), and residual aneurysm (class 3).

RESULTS

Initially, CE-MRA demonstrated 67 (50%) complete obliterations (class 1), 57 (41.79%) residual necks (class 2), and 8 (5.97%) residual aneurysms (class 3). No patient experienced rebleed during the follow-up period. A total of 214 patient-years of follow-up were obtained (range, 0-53 months). Two (1.49%) patients died after the follow-up, and 11 (8.21%) patients were lost to follow-up. On follow-up, 76 (56.72%) patients showed stable results. Fifty-six (41.79%) aneurysms showed change in their obliteration pattern. Of these 56, 47 demonstrated recanalization and 9 (6.72%) showed further obliteration. Most of the aneurysms that showed change in their obliteration remained stable on follow-up. Only 11 (8.21% of the total and 23.4% of those who showed recanalization) patients underwent recoiling or clipping.

CONCLUSIONS

CE-MRA can be used in routine practice to follow-up aneurysm recanalization noninvasively. CE-MRA permits close-interval follow-up and may show more filling of the aneurysm neck or sac than DSA.

Vertebral body signal changes in spinal cord infarction: histopathological confirmation

Spinal cord infarctions are rare. They are difficult to diagnose clinically and remain undiagnosed even after extensive investigations. Magnetic Resonance (MR) features include hyperintensity of the cord on T2W images. Few cases of spinal cord infarction associated with vertebral body infarction are reported in the literature. We describe another five cases of spinal cord infarction with histopathological confirmation of the vertebral body signal changes. MR examinations of five patients who presented with acute spontaneous spinal cord syndrome were reviewed. Abnormal MR features of the spinal cord included signal changes within the parenchyma, best demonstrated on T2W images. These cord changes were associated with vertebral body T2 hyperintensity in all the patients and in one patient, the computed tomography guided biopsy of vertebral body lesion reported infarction. MR is sensitive to detect spinal cord infarctions and associated vascular and bony changes. The associated signal abnormalities in the bone marrow are a corroborative sign in the diagnosis of spinal cord infarction which was proved by histopathology.

Spontaneous resolution of bilateral superior ophthalmic vein and cavernous sinus thrombosis. A case report

Superior ophthalmic vein thrombosis is uncommon, and bilateral superior ophthalmic vein thrombosis is rarer still. The resolution of bilateral superior ophthalmic vein thrombosis takes a long time. The spontaneous resolution of bilateral superior ophthalmic vein thrombosis is not known and not reported in the literature so far. Here we present MRI of bilateral superior ophthalmic vein thrombosis and its spontaneous resolution.