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.

T2 Hypointensity Aids in the Diagnosis of Intracranial Metastatic Adenocarcinoma.

BACKGROUND: The T2 hypointensity has been suggested to be associated with intracranial metastatic adenocarcinomas (IMA). The purpose of our study was to determine the association of T2 hypointensity with IMA. METHODS: All patients with pathologically confirmed metastatic brain tumors who had a magnetic resonance imaging (MRI) at our institution in the last 10 years were retrospectively assessed. Qualitative assessment of the lesions on MRI was done by two separate readers who were blinded to the pathological diagnosis. For qualitative assessment, the T2 hypointensity in the lesion was compared with the contralateral normal appearing white matter. Odds ratio, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. RESULTS: Of 107 patients with intracranial metastasis, only 73 (40 females; 33 males; mean age 61 years) had MRI available for review. Of these, only 46 (25 females; 21 males; mean age 61 years) had pathologically proven IMA. T2 hypointensity was seen in 20% of IMA. The odds ratio of T2 hypointensity in IMA was 3 compared to nonadenocarcinomas but was not statistically significant (p = 0.16). Intralesional hemorrhage was seen in 20. When controlled for hemorrhage, the odds ratio for T2 hypointensity in IMA was 4.7. The specificity, sensitivity, PPV, and NPV for T2 hypointensity to diagnose IMA were 92%, 19%, 81%, and 40%, respectively. CONCLUSION: T2 hypointensity was seen only in 20% of IMA with an odds ratio of 4.7. T2 hypointensity showed a high specificity and PPV for diagnosis of IMA.

Diagnosing Neoplastic Hematoma: Role of MR Perfusion.

BACKGROUND: The imaging appearance of neoplastic hematoma can be complicated by the presence of a large hematoma, even on magnetic resonance imaging (MRI). We describe the role of MR perfusion (MRP) in detecting neoplastic hematomas in patients with intraparenchymal hematoma (IPH). MATERIAL AND METHODS: A retrospective review was performed for consecutive patients with IPH, where MRP was performed. Routine, post-gadolinium MRI and MRP were analyzed. All patients were either operated on for evacuation of IPH or followed up on imaging. The MRP parameters of cerebral blood volume (CBV) and cerebral blood flow (CBF) and pattern of enhancement (peripheral linear vs. nodular) were recorded. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated for these parameters for diagnosing neoplastic hematoma. RESULTS: Of 116 patients with MRP, 16 patients (male 8; mean age-65.5 years) had IPH on their initial MRI. For diagnosing neoplastic hematoma, the sensitivity, specificity, PPV and NPV for increased CBF and CBV were 100%, 88.9%, 87.5%, and 100%; for peripheral linear enhancement were 100%, 28.6%, 50%, 100% and for nodular enhancement were 85.7%, 77.8%, 75% and 12.5%, respectively. The combination of peripheral linear enhancement and increased CBF and CBV showed 100% sensitivity, specificity, PPV and NPV. CONCLUSION: In our small series, the combination of peripheral linear enhancement and increased CBF and CBV showed 100% sensitivity, specificity, PPV and NPV for diagnosing a neoplastic hematoma. These findings need to be validated in a larger study.

Diffusion weighted imaging may help differentiate intracranial hemangiopericytoma from meningioma.

BACKGROUND AND PURPOSE: Hemangiopericytoma and meningioma appear similar on routine diagnostic imaging and hence are difficult to distinguish. The purpose of our study was to examine the diffusion weighted imaging (DWI) characteristics of these two types of tumours. METHODS: In a retrospective study, each patient with hemangiopericytoma was matched with two meningioma patients based on tumour location and size. Minimum and mean apparent diffusion coefficients (ADC) were measured in the tumour and the contralateral normal-appearing white matter (NAWM). A normalized ADC was calculated. The two tumour types were subjectively assessed for heterogeneity on ADC maps. RESULTS: Of the 14 patients with histopathological proven hemangiopericytoma, only 7 had available DWI for analysis. These 7 patients were matched based on tumour location and size with 14 patients out of the 209 meningioma patients screened. Hemangiopericytomas were more heterogeneous on ADC maps (P < 0.001) and had a higher mean ADC compared to that of meningiomas (P < 0.001). CONCLUSION: Hemangiopericytomas showed heterogeneity on DWI and significantly higher ADC compared to that of meningiomas in our small study. These observations need to be confirmed in future studies with larger sample sizes.

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.

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.

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.

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.

Normalized Apparent Diffusion Coefficient in the Prognostication of Patients with Glioblastoma Multiforme.

BACKGROUND: Glioblastoma multiforme (GBM) is known to have poor prognosis, with no available imaging marker that can predict survival at the time of diagnosis. Diffusion weighted images are used in characterisation of cellularity and necrosis of GBM. The purpose of this study was to assess whether pattern or degree of diffusion restriction could help in the prognostication of patients with GBM. MATERIAL AND METHODS: We retrospectively analyzed 84 consecutive patients with confirmed GBM on biopsy or resection. The study was approved by the institutional ethics committee. The total volume of the tumor and total volume of tumor showing restricted diffusion were calculated. The lowest Apparent Diffusion Coefficient (ADC) in the region of the tumor and in the contralateral Normal Appearing White Matter were calculated in order to calculate the nADC. Treatment and follow-up data in these patients were recorded. Multivariate analsysis was completed to determine significant correlations between different variables and the survival of these patients. RESULTS: Patient survival was significantly related to the age of the patient (p<0.0001; 95% CI-1.022-1.043) and the nADC value (p=0.014; 95% CI-0.269-0.860) in the tumor. The correlation coefficients of age and nADC with survival were -0.335 (p=0.002) and 0.390 (p<0.001), respectively. Kaplan Meier survival function, grouped by normalized Apparent Diffusion Coefficient cut off value of 0.75, was significant (p=0.007). CONCLUSION: The survival of patients with GBM had small, but significant, correlations with the patient's age and nADC within the tumor.

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.

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.

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.

Iterative Reconstruction for Head CT: Effects on Radiation Dose and Image Quality.

BACKGROUND: Iterative reconstruction has been reported to reduce radiation dose in CT, while preserving and even improving image quality. The purpose of this study was to evaluate the effects of sinogram-affirmed iterative reconstruction (SAFIRE) on radiation dose reduction and image quality for noncontrast adult head CT and to compare SAFIRE with conventional filtered back-projection (FBP) reconstruction. METHODS: Institutional review board approval was obtained for this retrospective analysis of head CT scans reconstructed with SAFIRE and/or FBP for 107 patients. Radiation dose parameters were recorded from scanner-generated CT dose reports. Signal-to-noise and contrast-to-noise ratios (SNR, CNR) were calculated from gray and white matter (GM, WM) attenuation measurements. Image noise, artifacts, GM-WM differentiation, small structure visibility, and sharpness were graded by two readers. Statistical analysis included the independent-samples t test for quantitative data, the related samples Wilcoxon signed-rank test for qualitative data, the coefficient of repeatability for intraobserver variation, and κ statistics for interobserver agreement. RESULTS: Mean effective dose was significantly reduced with SAFIRE from 2.0 to 1.7 mSv (p<0.0001). SAFIRE also significantly improved GM SNR, WM SNR, and GM-WM CNR (p<0.0001). Significant reductions in image noise and posterior fossa artifact as well as improvements in GM-WM differentiation, small structure visibility, and sharpness were noted with SAFIRE (P<0.005). CONCLUSIONS: SAFIRE for noncontrast adult head CT reduces patient radiation dose by 15% for the settings employed at our institution, while significantly improving multiple quantitative and qualitative measures of image quality.

Evaluation of perfusion CT in grading and prognostication of high-grade gliomas at diagnosis: a pilot study.

OBJECTIVE: Differentiation of grade 3 astrocytoma from glioblastoma multiforme can be difficult with conventional structural imaging but is important for prognosis. The purpose of this study was to assess perfusion CT in differentiating high-grade gliomas (HGGs) and their role in prognosis in the care of patients with HGG. SUBJECTS AND METHODS: Twenty patients with previously untreated HGG underwent prospective evaluation with perfusion CT. Permeability surface area product (PS) and cerebral blood volume (CBV) were calculated by the deconvolution method and were compared between HGGs with Student two-sample t tests. Receiver operating characteristic curves were generated for PS, CBV, and the conjoint factor PS + CBV. Cox regression analysis was used to correlate these parameters with patient survival over a follow-up period. Hazard ratios were calculated, and Kaplan-Meier survival curves were drawn. RESULTS: There was a significant difference between grade 3 and grade 4 gliomas for PS (p = 0.022) and PS + CBV (p = 0.019) but not for CBV alone (p = 0.411). Receiver operating characteristic analyses showed that PS (area under the curve [AUC], 0.72) and CBV + PS (AUC, 0.73) can be used to differentiate grade 3 from grade 4 gliomas but that CBV alone cannot be so used (AUC, 0.54). There was a significant relation between patient outcome and age (p = 0.034) and CBV + PS (p = 0.048). Patients with HGG and a CBV + PS greater than 9 had a poor outcome (hazard ratio, 6.00). CONCLUSION: PS and CBV + PS can be used to differentiate grade 3 from grade 4 gliomas. The outcome of patients with HGG depends on age and CBV + PS.

SILK flow diverter for treatment of intracranial aneurysms: initial experience and cost analysis.

BACKGROUND: The flow diverting stent is a new and expansive tool in the endovascular therapy of complex intracranial aneurysms. We present our experience using SILK flow diverter (SFD) in patients with complex intracranial aneurysms, and a cost analysis. METHODS: Between September 2010 and May 2012, 19 consecutive patients with 29 complex intracranial aneurysms were treated with SFD without the adjunctive use of coils. We retrospectively evaluated the technical aspects, thromboembolic events, adjunctive therapies, and short term results in patients with complex intracranial aneurysms treated with SFD. A cost analysis of patients who were treated with SFD was performed and compared with similar sized aneurysms coiled with stent assisted coiling. RESULTS: The primary technical success rate was 100%. An adjunctive device was required in two of our patients. The technique related complication rate and the 30 day mortality and morbidity rates were 5% (1/20) and 10% (2/20), respectively. We had a total of 263 patient months of clinical and 166 patient months of imaging follow-up. Follow-up imaging revealed two asymptomatic occlusions of the parent artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 59% of patients where follow-up images were available. The cost analysis showed that the mean cost of treatment with SFD was significantly cheaper compared with the presumed cost of stent assisted coiling (p<0.001). CONCLUSIONS: The SFD provides a very feasible, efficient, relatively safe, and cost effective method to treat complex intracranial aneurysms without the use of adjunct coiling.

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.

Whole-brain perfusion imaging with 320-MDCT scanner: Reducing radiation dose by increasing sampling interval.

OBJECTIVE: The purpose of this study was to investigate whether perfusion CT values obtained with a reduced-dose imaging protocol on a 320-MDCT scanner are similar to those obtained with a standard protocol. CONCLUSION: Similar perfusion values at one-half the radiation dose can be obtained with the alternative algorithm used in this study.

A rare case of cerebral cortical dysplasia with arterial vascular dysplasia.

BACKGROUND: Cortical dysplasias are rarely associated with vascular anomalies. They are usually associated with venous anomalies or in few cases with both arterial and venous anomalies. METHODS: Twenty-six year old female presented with history of headache showed cortical dysplasia associated with pure arterial dysplasia in the absence of any associated venous anomaly. CONCLUSIONS: An abnormal arterial supply to or an abnormal venous drainage from the growing cortex may result in cortical rearrangements that eventually give rise to various neuronal migration anomalies.