The collateral map: prediction of lesion growth and penumbra after acute anterior circulation ischemic stroke

OBJECTIVES

This study evaluated the collateral map's ability to predict lesion growth and penumbra after acute anterior circulation ischemic strokes.

METHODS

This was a retrospective analysis of selected data from a prospectively collected database. The lesion growth ratio was the ratio of the follow-up lesion volume to the baseline lesion volume on diffusion-weighted imaging (DWI). The time-to-maximum (Tmax)/DWI ratio was the ratio of the baseline Tmax  > 6 s volume to the baseline lesion volume. The collateral ratio was the ratio of the hypoperfused lesion volume of the phase_FU (phase with the hypoperfused lesions most approximate to the follow-up DWI lesion) to the hypoperfused lesion volume of the phase_baseline of the collateral map. Multiple logistic regression analyses were conducted to identify independent predictors of lesion growth. The concordance correlation coefficients of Tmax/DWI ratio and collateral ratio for lesion growth ratio were analyzed.

RESULTS

Fifty-two patients, including twenty-six males (mean age, 74 years), were included. Intermediate (OR, 1234.5; p < 0.001) and poor collateral perfusion grades (OR, 664.7; p = 0.006) were independently associated with lesion growth. Phase_FUs were immediately preceded phases of the phase_baselines in intermediate or poor collateral perfusion grades. The concordance correlation coefficients of the Tmax/DWI ratio and collateral ratio for the lesion growth ratio were 0.28 (95% CI, 0.17-0.38) and 0.88 (95% CI, 0.82-0.92), respectively.

CONCLUSION

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments. Further studies are needed to generalize the findings of this study.

CLINICAL RELEVANCE STATEMENT

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments.

KEY POINTS

• Cell viability in cerebral ischemia due to proximal arterial steno-occlusion mainly depends on the collateral circulation. • The collateral map shows salvageable brain extent, which can survive by recanalization treatments after acute anterior circulation ischemic stroke. • Precise estimation of salvageable brain makes it possible to make patient-specific treatment decision.

Impact of Collateral Circulation on Futile Endovascular Thrombectomy in Acute Anterior Circulation Ischemic Stroke

OBJECTIVE

Collateral circulation is associated with the differential treatment effect of endovascular thrombectomy (EVT) in acute ischemic stroke. We aimed to verify the ability of the collateral map to predict futile EVT in patients with acute anterior circulation ischemic stroke.

METHODS

This secondary analysis of a prospective observational study included data from participants underwent EVT for acute ischemic stroke due to occlusion of the internal carotid artery and/or the middle cerebral artery within 8 hours of symptom onset. Multiple logistic regression analyses were conducted to identify independent predictors of futile recanalization (modified Rankin scale score at 90 days of 4-6 despite of successful reperfusion).

RESULTS

In a total of 214 participants, older age (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.56 to 3.67; p<0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR, 1.12; 95% CI, 1.04 to 1.21; p=0.004), very poor collateral perfusion grade (OR, 35.09; 95% CI, 3.50 to 351.33; p=0.002), longer door-to-puncture time (OR, 1.08; 95% CI, 1.02 to 1.14; p=0.009), and failed reperfusion (OR, 3.73; 95% CI, 1.30 to 10.76; p=0.015) were associated with unfavorable functional outcomes. In 184 participants who achieved successful reperfusion, older age (OR, 2.30; 95% CI, 1.44 to 3.67; p<0.001), higher baseline NIHSS scores (OR, 1.12; 95% CI, 1.03 to 1.22; p=0.006), very poor collateral perfusion grade (OR, 4.96; 95% CI, 1.42 to 17.37; p=0.012), and longer door-to-reperfusion time (OR, 1.09; 95% CI, 1.03 to 1.15; p=0.003) were associated with unfavorable functional outcomes.

CONCLUSION

The assessment of collateral perfusion status using the collateral map can predict futile EVT, which may help select ineligible patients for EVT, thereby potentially reducing the rate of futile EVT.

Prognostic value of collateral perfusion estimation by arterial spin labeling for acute anterior circulation ischemic stroke

PURPOSE

This study aimed to verify the value of arterial spin labeling (ASL) collateral perfusion estimation for predicting functional outcomes in acute anterior circulation ischemic stroke.

METHODS

This secondary analysis of an ongoing prospective observational study included data from participants with acute ischemic stroke due to steno-occlusion of the internal carotid artery and/or the middle cerebral artery within 8 h of symptom onset. We compared the collateral map, which is a 5-phase collateral imaging derived from dynamic contrast-enhanced magnetic resonance angiography, and ASL to validate the ASL collateral perfusion estimation. Multiple logistic regression analyses were conducted to identify independent predictors of favorable functional outcomes.

RESULTS

One hundred forty-eight participants (68 ± 13 years, 96 men) were evaluated. The ASL collateral perfusion grade was positively correlated with the collateral perfusion grade of the collateral map (P < .001). Younger age (OR = 0.53, 95% CI = 0.36-0.78, P = .002), lower baseline NIHSS score (OR = 0.85, 95% CI = 0.78-0.92, P < .001), intermediate ASL collateral perfusion grade (OR = 4.02, 95% CI = 1.43-11.26, P = .008), good ASL collateral perfusion grade (OR = 26.37, 95% CI = 1.06-655.01, P = .046), and successful reperfusion (OR = 5.84, 95% CI = 2.08-16.42, P < .001) were independently associated with favorable functional outcomes.

CONCLUSION

ASL collateral perfusion estimation provides prognostic information, which can be helpful in guiding management decisions.

Perfusion Maps Acquired From Dynamic Angiography MRI Using Deep Learning Approaches

BACKGROUND

A typical stroke MRI protocol includes perfusion-weighted imaging (PWI) and MR angiography (MRA), requiring a second dose of contrast agent. A deep learning method to acquire both PWI and MRA with single dose can resolve this issue.

PURPOSE

To acquire both PWI and MRA simultaneously using deep learning approaches.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 60 patients (30-73 years old, 31 females) with ischemic symptoms due to occlusion or ≥50% stenosis (measured relative to proximal artery diameter) of the internal carotid artery, middle cerebral artery, or anterior cerebral artery. The 51/1/8 patient data were used as training/validation/test.

FIELD STRENGTH/SEQUENCE

A 3 T, time-resolved angiography with stochastic trajectory (contrast-enhanced MRA) and echo planar imaging (dynamic susceptibility contrast MRI, DSC-MRI).

ASSESSMENT

We investigated eight different U-Net architectures with different encoder/decoder sizes and with/without an adversarial network to generate perfusion maps from contrast-enhanced MRA. Relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), mean transit time (MTT), and time-to-max (T_max ) were mapped from DSC-MRI and used as ground truth to train the networks and to generate the perfusion maps from the contrast-enhanced MRA input.

STATISTICAL TESTS

Normalized root mean square error, structural similarity (SSIM), peak signal-to-noise ratio (pSNR), DICE, and FID scores were calculated between the perfusion maps from DSC-MRI and contrast-enhanced MRA. One-tailed t-test was performed to check the significance of the improvements between networks. P values < 0.05 were considered significant.

RESULTS

The four perfusion maps were successfully extracted using the deep learning networks. U-net with multiple decoders and enhanced encoders showed the best performance (pSNR 24.7 ± 3.2 and SSIM 0.89 ± 0.08 for rCBV). DICE score in hypo-perfused area showed strong agreement between the generated perfusion maps and the ground truth (highest DICE: 0.95 ± 0.04).

DATA CONCLUSION

With the proposed approach, dynamic angiography MRI may provide vessel architecture and perfusion-relevant parameters simultaneously from a single scan.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 5.

Acute hemicranial pain accompanied with a pearl and string type dissection of intracranial vertebral artery: Consideration for the time when to finish the medical observation

The International Classification of Headache Disorder (ICHD) clearly guides the suspicion of intracranial vertebral artery dissection (ICVAD) in headache patients, but guidelines on how observational or imaging studies should be performed to detect dangerous progression early are unclear. Fifty-six cases with pearl and string type intracranial vertebral artery dissection were divided into 3 groups: 39 in the headache group, 6 in the infarction group, and 11 in the hemorrhagic group. Clinical and angiographic data were analyzed and compared. Most headaches resolved within 2 weeks and did not exceed 8 weeks. Of the 33 patients (84.6%) who underwent continuous follow-up imaging, 18 (54.5%) returned to normal, but 3 (9%) had deteriorated. All the patients survived without subsequent bleeding or infarction. Image changes started before 3rd month and ended after 6 to 7 months. In acute ICVADs, image changes occur at the same time as the headache resolves and continue for several months after the headache has subsided. Since the dissection is likely to worsen even after the headache disappears, the image changes continue over several months, and prediction of rupture of unruptured ICVAD is unpredictable, it is desirable to conduct continuous imaging studies regularly after the initiation of dissection until stabilization is confirmed.

A 3D Multi-task Regression and Ordinal Regression Deep Neural Network for Collateral Imaging from Dynamic Susceptibility Contrast-Enhanced MR perfusion in Acute Ischemic Stroke

BACKGROUND AND OBJECTIVE

Cerebral collaterals have been identified as one of the primary determinants for treatment options in acute ischemic stroke. Several works have been proposed, but these have not been adopted for a routine clinical usage due to their manual and heuristic nature as well as inconsistency and instability of the assessment. Herein, we present an advanced deep learning-based method that can automatically generate a multiphase collateral imaging (collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion (DSC-MRP) in an accurate and robust manner.

METHODS

We develop a 3D multi-task regression and ordinal regression deep neural network for generating collateral maps from DSC-MRP, which formulates the prediction of collateral maps as both a regression task and an ordinal regression task. For an ordinal regression task, we introduce a spacing-decreasing discretization (SDD) strategy to represent the intensity of the collateral status on a discrete, ordinal scale. We also devise loss functions to achieve effective and efficient multi-task learning.

RESULTS

We systematically evaluated the performance of the proposed network using DSC-MRP from 802 patients. On average, the proposed network achieved ≥0.900 squared correlation coefficient (R-Squared), ≥0.916 Tanimoto measure (TM), ≥0.0913 structural similarity index measure (SSIM), and ≤0.564 × 10^-1 mean absolute error (MAE), outperforming eight competing models that have been recently developed in medical imaging and computer vision. We also found that the proposed network could provide an improved contrast between the low and high intensity regions in the collateral maps, which is a key to an accurate evaluation of the collateral status.

CONCLUSIONS

The experimental results demonstrate that the proposed network is able to generate collateral maps with high accuracy, facilitating a timely and prompt assessment of the collateral status in clinlcs. The future study will entail the optimization of the proposed network and its clinical evalution in a prospective manner.

Imaging in Acute Anterior Circulation Ischemic Stroke: Current and Future

Clinical trials on acute ischemic stroke have demonstrated the clinical effectiveness of revascularization treatments within an appropriate time window after stroke onset: intravenous thrombolysis (NINDS and ECASS-III) through the administration of tissue plasminogen activator within a 4.5-hour time window, endovascular thrombectomy (ESCAPE, REVASCAT, SWIFT-PRIME, MR CLEAN, EXTEND-IA) within a 6-hour time window, and extending the treatment time window up to 24 hours for endovascular thrombectomy (DAWN and DEFUSE 3). However, a substantial number of patients in these trials were ineligible for revascularization treatment, and treatments of some patients were considerably futile or sometimes dangerous in the clinical trials. Guidelines for the early management of patients with acute ischemic stroke have evolved to accept revascularization treatment as standard and include eligibility criteria for the treatment. Imaging has been crucial in selecting eligible patients for revascularization treatment in guidelines and clinical trials. Stroke specialists should know imaging criteria for revascularization treatment. Stroke imaging studies have demonstrated imaging roles in acute ischemic stroke management as follows: 1) exclusion of hemorrhage and stroke mimic disease, 2) assessment of salvageable brain, 3) localization of the site of vascular occlusion and thrombus, 4) estimation of collateral circulation, and 5) prediction of acute ischemic stroke expecting hemorrhagic transformation. Here, we review imaging methods and criteria to select eligible patients for revascularization treatment in acute anterior circulation stroke, focus on 2019 guidelines from the American Heart Association/American Stroke Association, and discuss the future direction of imaging-based patient selection to improve treatment effects.

Facial Nerve Hematoma After Penetrating Middle Ear Trauma: A Cause of Delayed Facial Palsy

ABSTRACT

Penetrating middle ear injury may cause hearing loss, vertigo, or facial nerve injury, although facial nerve paralysis followed by head trauma is a rare condition. In this study, we report a case of a 3-year-old patient with delayed facial palsy on the left side that developed 4 days after an accidental tympanic membrane perforation caused by a cotton-tipped swab. Otoendoscopic examination revealed a perforation in the posterosuperior quadrant of the tympanic membrane. Audiometry revealed no hearing loss on the injured side, and eye movement examination did not reveal spontaneous or positional nystagmus. Pre- and postcontrast T1-weighted magnetic resonance imaging demonstrated high signal intensity along the tympanic portion of the fallopian canal, which suggested that hemorrhage within the facial canal may be a cause of delayed facial palsy. It can be assumed that traumatic injury at the dehiscent facial nerve in the tympanic portion caused hematoma within the fallopian canal, resulting in delayed facial nerve palsy.

Global impact of COVID-19 on stroke care

Background

The COVID-19 pandemic led to profound changes in the organization of health care systems worldwide.

Aims

We sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March–31 May 2020) compared with two control three-month periods (immediately preceding and one year prior).

Methods

Retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers.

Results

The hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, −19.7 to −18.7), 11.5% (95%CI, −12.6 to −10.6), and 12.7% (95%CI, −13.6 to −11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (−20.5%) had greater declines in mechanical thrombectomy volumes than mid- (−10.1%) and low-volume (−8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions.

Conclusion

The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

Background

During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines.

Methods

We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March–31 May 2020. The prior 1-year control period (1 March–31 May 2019) was obtained to account for seasonal variation.

Findings

There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI −24.3% to −20.7%, p<0.0001). Embolisation of ruptured aneurysms declined with 1170–1035 procedures, respectively, representing an 11.5% (95%CI −13.5% to −9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI −28.0% to −22.1%, p<0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile.

Interpretation

There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction.

Unusual clinicopathological presentation of nontraumatic cerebral fat embolism: Two-case report

RATIONALE

Fat embolism syndrome (FES) is characterized by the classical triad of cerebral, respiratory, and cutaneous manifestations. In contrast, cerebral fat embolism (CFE), corresponding to incomplete pure type FES, is much rarer and usually follows trauma. CFE typically shows a "starfield" pattern on diffusion-weighted magnetic resonance imaging due to the involvement of multiple small arteries. We report 2 unusual cases of CFE that showed a nontraumatic etiology and the involvement of a single dominant cerebral artery.

PATIENT CONCERNS

Case 1 was a 33-year-old woman without a history of trauma who visited the emergency room due to hemiparesis and hemisensory deficits. She was a heavy smoker and had used oral contraceptives for several years. Most importantly, she had 2 experiences of autologous fat grafting 2 months previously. Magnetic resonance angiography (MRA) revealed acute occlusion of the right middle cerebral artery. Case 2 was an 80-year-old man suddenly presented with dizziness, ataxia, and left-sided sensorimotor dysfunction. He had a history of hypertension, untreated atrial fibrillation, and chronic alcoholism. MRA demonstrated the occlusion of the distal basilar artery.

DIAGNOSIS

Case 1: Microscopic findings demonstrated variable sized fat vacuoles intermixed with moderate amounts of thrombi. Case 2: Histologically, mature adipocytes were intermingled with fibrin, blood cells, and a fragment of entrapped soft tissue resembling the vessel wall.

INTERVENTION

Case 1 and 2 underwent aspirational thrombectomy guided by transfemoral cerebral angiography.

OUTCOME

Case 1 recovered well but Case 2 still suffers from gait ataxia.

LESSONS

CFE can rarely occur in various nontraumatic conditions, with or without evident etiology. Furthermore, it may not show characteristic clinicopathological manifestations. Therefore, careful follow up of those who have undergone procedures that are likely to trigger FES or who have hemodynamic or hypercoagulable risk factors is needed.

Multiphase MR Angiography Collateral Map: Functional Outcome after Acute Anterior Circulation Ischemic Stroke

Background Collateral circulation determines tissue fate and affects treatment result in acute ischemic stroke. A precise method for collateral estimation in an optimal imaging protocol is necessary to make an appropriate treatment decision for acute ischemic stroke. Purpose To verify the value of multiphase collateral imaging data sets (MR angiography collateral map) derived from dynamic contrast material-enhanced MR angiography for predicting functional outcomes after acute ischemic stroke. Materials and Methods This secondary analysis of an ongoing prospective observational study included data from participants with acute ischemic stroke due to occlusion or stenosis of the unilateral internal carotid artery and/or M1 segment of the middle cerebral artery who were evaluated within 8 hours of symptom onset. Data were obtained from March 2016 through August 2018. The collateral grading based on the MR angiography collateral map was estimated by using six-scale MR acute ischemic stroke collateral (MAC) scores. To identify independent predictors of favorable functional outcomes, age, sex, risk factors, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline diffusion-weighted imaging (DWI) lesion volume, site of steno-occlusion, collateral grade, mode of treatment, and early reperfusion were evaluated with multiple logistic regression analyses. Results One hundred fifty-four participants (mean age ± standard deviation, 69 years ± 13; 99 men) were evaluated. Younger age (odds ratio [OR], 0.45; 95% confidence interval [CI]: 0.29, 0.70; P < .001), lower baseline NIHSS score (OR, 0.85; 95% CI: 0.78, 0.94; P < .001), MAC score of 3 (OR, 27; 95% CI: 4.0, 179; P < .001), MAC score of 4 (OR, 17; 95% CI: 2.1, 134; P = .007), MAC score of 5 (OR, 27; 95% CI: 2.5, 306; P = .007), and successful early reperfusion (OR, 7.5; 95% CI: 2.6, 22; P < .001) were independently associated with favorable functional outcomes in multivariable analysis. There was a linear negative association between collateral perfusion grades and functional outcomes (P < .001). Conclusion An MR angiography collateral map was clinically reliable for collateral estimation in patients with acute ischemic stroke. This map provided patient-specific pacing information for ischemic progression. © RSNA, 2020.

Abstract WMP13: Multiphase MRA Collateral Map: Prediction of Tissue Outcome and Penumbra in Patients With Acute Ischemic Stroke in the Anterior Circulation

Background and Purpose: We developed the MRA collateral map derived from dynamic MR angiography and grading methods with significant linear association with functional outcomes of patients with acute ischemic stroke (AIS). This study is to verify the value of the MRA collateral map for predicting tissue outcome and penumbra in patients with AIS.

Materials and Methods: From a prospectively maintained registry, patients with AIS due to occlusion or stenosis of the unilateral ICA and/or M1 MCA within 8 hours of symptom onset were included. The collateral-perfusion grading based on the MRA collateral map was estimated using 6-scale MAC. Changes of infarct area were divided into two groups with and without infarct growth (IG + and IG - ). Areas of baseline DWI lesion, Tmax > 6s, and decreased collateral-perfusion on each phases of the MRA collateral map, and infarct lesion on follow-up image were compared by visual assessment.

Results: One hundred thirty-five patients, including 85 males (mean age, 69 years old), were included. Shorter onset-to-door times (OR=1.04, 95% CI=1.01-1.08) and successful early reperfusion (OR=0.19, 95% CI=0.05-0.66) were independently associated with IG - in multivariate analysis. In subgroup analysis, good collateral-perfusion status was associated with IG - (OR=0.30, 95% CI=0.10-0.91). In IG + group, the infarction grew within hypoperfused area on the phase of the MRA collateral map immediately before the phase that matches the baseline DWI lesion. There was no infarct growth beyond hypoperfused area on the capillary phase of the MRA collateral map in both IG + and IG - groups. The area of Tmax > 6s matched with the hypoperfused area on capillary phase of the MRA collateral map in 83% of patients.

Conclusion: In this study, tissue fate in AIS was dependent on early reperfusion. In case of unsuccessful early reperfusion, it was associated with collateral-perfusion status. We suggest that the extent of penumbra can be estimated by the MRA collateral map.

Number of Stent Retriever Passes Associated With Futile Recanalization in Acute Stroke

Background and Purpose- Stent retriever (SR) thrombectomy has become the mainstay of treatment of acute intracranial large artery occlusion. However, it is still not much known about the optimal limit of SR attempts for favorable outcome. We evaluated whether a specific number of SR passes for futile recanalization can be determined. Methods- Patients who were treated with a SR as the first endovascular modality for their intracranial large artery occlusion in anterior circulation were retrospectively reviewed. The recanalization rate for each SR pass was calculated. The association between the number of SR passes and a patient's functional outcome was analyzed. Results- A total of 467 patients were included. Successful recanalization by SR alone was achieved in 82.2% of patients. Recanalization rates got sequentially lower as the number of passes increased, and the recanalization rate achievable by ≥5 passes of the SR was 5.5%. In a multivariable analysis, functional outcomes were more favorable in patients with 1 to 4 passes of the SR than in patients without recanalization (odds ratio [OR] was 8.06 for 1 pass; OR 7.78 for 2 passes; OR 6.10 for 3 passes; OR 6.57 for 4 passes; all P<0.001). However, the functional outcomes of patients with ≥5 passes were not significantly more favorable than found among patients without recanalization (OR 1.70 with 95% CI, 0.42-6.90 for 5 passes, P=0.455; OR 0.33 with 0.02-5.70, P=0.445 for ≥6 passes). Conclusions- The likelihood of successful recanalization got sequentially lower as the number of SR passes increased. Five or more passes of the SR became futile in terms of the recanalization rate and functional outcomes.

A Novel Collateral Imaging Method Derived from Time-Resolved Dynamic Contrast-Enhanced MR Angiography in Acute Ischemic Stroke: A Pilot Study

BACKGROUND AND PURPOSE

Assessment of the collateral status has been emphasized for appropriate treatment decisions in patients with acute ischemic stroke. The purpose of this study was to introduce a multiphase MRA collateral imaging method (collateral map) derived from time-resolved dynamic contrast-enhanced MRA and to verify the value of the multiphase MRA collateral map in acute ischemic stroke by comparing it with the multiphase collateral imaging method (MRP collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion.

MATERIALS AND METHODS

From a prospectively maintained registry of acute ischemic stroke, MR imaging data of patients with acute ischemic stroke caused by steno-occlusive lesions of the unilateral ICA and/or the M1 segment of the MCA were analyzed. We generated collateral maps using dynamic signals from dynamic contrast-enhanced MRA and DSC-MRP using a Matlab-based in-house program and graded the collateral scores of the multiphase MRA collateral map and the MRP collateral map independently. Interobserver reliabilities and intermethod agreement between both collateral maps for collateral grading were tested.

RESULTS

Seventy-one paired multiphase MRA and MRP collateral maps from 67 patients were analyzed. The interobserver reliabilities for collateral grading using multiphase MRA or MRP collateral maps were excellent (weighted κ = 0.964 and 0.956, respectively). The agreement between both collateral maps was also excellent (weighted κ = 0.884; 95% confidence interval, 0.819-0.949).

CONCLUSIONS

We demonstrated that the dynamic signals of dynamic contrast-enhanced MRA could be used to generate multiphase collateral images and showed the possibility of the multiphase MRA collateral map as a useful collateral imaging method in acute ischemic stroke.

Carotid Artery Stenting and Intracranial Thrombectomy for Tandem Cervical and Intracranial Artery Occlusions

BACKGROUND

It remains controversial whether carotid artery stenting (CAS) is needed in cases of tandem cervical internal carotid artery occlusion (cICAO) and intracranial large vessel occlusion (LVO).

OBJECTIVE

To investigate the efficacy and safety of CAS in combination with endovascular thrombectomy (CAS-EVT) in cICAO-LVO patients and to compare its outcomes with those of EVT without CAS (EVT-alone).

METHODS

We identified all patients who underwent EVT for tandem cICAO-LVO from the prospectively maintained registries of 17 stroke centers. Patients were classified into 2 groups: CAS-EVT and EVT-alone. Clinical characteristics and procedural and clinical outcomes were compared between 2 groups. We tested whether CAS-EVT strategy was independently associated with recanalization success.

RESULTS

Of the 955 patients who underwent EVT, 75 patients (7.9%) had cICAO-LVO. Fifty-six patients underwent CAS-EVT (74.6%), and the remaining 19 patients underwent EVT-alone (25.4%). The recanalization (94.6% vs 63.2%, P = .002) and good outcome rates (64.3% vs 26.3%, P = .007) were significantly higher in the CAS-EVT than in the EVT-alone. Mortality was significantly lower in the CAS-EVT (7.1% vs 21.6%, P = .014). There was no significant difference in the rate of symptomatic intracranial hemorrhage between 2 groups (10.7 vs 15.8%; P = .684) and according to the use of glycoprotein IIb/IIIa inhibitor (10.0% vs 12.3%; P = .999) or antiplatelet medications (10.2% vs 18.8%; P = .392). CAS-EVT strategy remained independently associated with recanalization success (odds ratio: 24.844; 95% confidence interval: 1.445-427.187).

CONCLUSION

CAS-EVT strategy seemed to be effective and safe in cases of tandem cICAO-LVO. CAS-EVT strategy was associated with recanalization success, resulting in better clinical outcome.

Need for rescue treatment and its implication: stent retriever versus contact aspiration thrombectomy

Backgroud

The need for rescue treatment (RT) may differ depending on first-line modality (stent retriever (SR) or contact aspiration (CA)) in endovascular thrombectomy (EVT). We aimed to investigate whether the type of first-line modality in EVT was associated with the need for RT.

Methods

We identified all patients who underwent EVT for anterior circulation large-vessel occlusion from prospectively maintained registries of 17 stroke centers. Patients were dichotomized into SR-first and CA-first. RT involved switching to the other device, balloon angioplasty, permanent stenting, thrombolytics, glycoprotein IIb/IIIa antagonist, or any combination of these. We compared clinical characteristics, procedural details, and final recanalization rate between the two groups and assessed whether first-line modality type was associated with RT requirement and if this affected clinical outcome.

Results

A total of 955 patients underwent EVT using either SR-first (n=526) or CA-first (n=429). No difference occurred in the final recanalization rate between SR-first (82.1%) and CA-first (80.2%). However, recanalization with the first-line modality alone and first-pass recanalization rates were significantly higher in SR-first than in CA-first. CA-first had more device passes and higher RT rate. The RT group had significantly longer puncture-to-recanalization time (93±48 min versus 53±28 min). After adjustment, CA-first remained associated with RT (OR, 1.367; 95% CI, 1.019 to 1.834). RT was negatively associated with good outcome (OR, 0.597; 95% CI, 0.410 to 0.870).

Conclusion

CA was associated with requiring RT, while recanalization with first-line modality alone and first-pass recanalization rates were higher with SR. RT was negatively associated with good outcome.

Seizure in code stroke: Stroke mimic and initial manifestation of stroke

BACKGROUND

Although seizure is one of the common causes of stroke mimics and can be an initial manifestation of acute stroke, accurate diagnosis of seizure during acute stroke management is frequently difficult. The objective of this study was to analyze the frequency, characteristics and results of neuroimaging including CT perfusion in patients with seizures manifesting initially as stroke-like symptoms.

METHODS

We retrospectively reviewed the medical records of patients who were treated with code stroke alarming system. We studied the frequency and characteristics of patients who were finally diagnosed with seizures and further correlated their clinical features with the results of neuroimaging including CT perfusion.

RESULTS

Among the 4673 patients who were treated with code stroke alarming system, seizure was the third most frequent diagnosis (188 patients, 4.0%) among the causes of stroke mimics including 27 patients who manifested seizure as an initial manifestation of acute stroke. CT perfusion showed perfusion changes in more than 25% of them (49 of 188 patients, 26.1%). Thrombolysis was not performed in six patients who presented with seizure as an initial presentation of stroke for delayed diagnosis while one patient underwent thrombolysis for misdiagnosis of seizure.

CONCLUSIONS

Seizure is a frequent final diagnosis in acute stroke management. However, careful interpretation of clinical features and results of perfusion imaging is necessary to avoid unnecessary thrombolysis in patients with seizure as a stroke mimic and thrombolysis failure due to delayed diagnosis of seizure as an initial manifestation of stroke.

Effect of balloon guide catheter utilization on contact aspiration thrombectomy

OBJECTIVE

The role of the balloon guide catheter (BGC) has not been evaluated in contact aspiration thrombectomy (CAT) for acute stroke. Here, the authors aimed to test whether the BGC was associated with recanalization success and good functional outcome in CAT.

METHODS

All patients who had undergone CAT as the first-line treatment for anterior circulation intracranial large vessel occlusion were retrospectively identified from prospectively maintained registries for six stroke centers. The patients were dichotomized into BGC utilization and nonutilization groups. Clinical findings, procedural details, and recanalization success rates were compared between the two groups. Whether the BGC was associated with recanalization success and functional outcome was assessed.

RESULTS

A total of 429 patients (mean age 68.4 ± 11.4 years; M/F ratio 215:214) fulfilled the inclusion criteria. A BGC was used in 45.2% of patients. The overall recanalization and good outcome rates were 80.2% and 52.0%, respectively. Compared to the non-BGC group, the BGC group had a significantly reduced number of CAT passes (2.6 ± 1.6 vs 3.4 ± 1.5), shorter puncture-to-recanalization time (56 ± 27 vs 64 ± 35 minutes), lower need for the additional use of thrombolytics (1.0% vs 8.1%), and less embolization to a distal or different site (0.5% vs 3.4%). The BGC group showed significantly higher final (89.2% vs 72.8%) and first-pass (24.2% vs 8.1%) recanalization success rates. After adjustment for potentially associated factors, BGC utilization remained independently associated with recanalization (OR 4.171, 95% CI 1.523-11.420) and good functional outcome (OR 2.103, 95% CI 1.225-3.612).

CONCLUSIONS

BGC utilization significantly increased the final and first-pass recanalization rates and remained independently associated with recanalization success and good functional outcome.

Secondary Aneurysmal Bone Cyst in a Craniofacial Fibrous Dysplasia: Case Report

Aneurysmal bone cyst (ABC) is a rare non-neoplastic bone lesion that involves mostly the long bones and vertebrae and may occur very rarely in the craniofacial bones. ABCs may occur as secondary bony pathologies in association with various benign and malignant bone tumors and with fibrous dysplasia (FD). FD is a common non-neoplastic bony pathology mostly affecting craniofacial bones. Secondary ABC occurring in craniofacial FD is extremely rare, with only approximately 20 cases reported in the literature to date. Here, we report on a case of secondary ABC in a 25-year-old woman who has had a craniofacial deformity for over 10 years and who presented to us with a rapidly growing painful pulsatile mass in the right frontal region that began over 2 months prior to admission. On thorough examination of computed tomography and magnetic resonance imaging brain scans taken at two-month interval, an aggressive, rapidly enlarging ABC, arising from the right frontal FD, was diagnosed. The patient underwent preoperative embolization followed by gross total resection of the ABC and cranioplasty. The 6-month follow up showed no recurrence of the ABC, nor was any progression of the FD noticed.

Collateral status affects the onset-to-reperfusion time window for good outcome

OBJECTIVE

To characterise the time window in which endovascular thrombectomy (EVT) is associated with good outcome, and to test the differential relationship between functional outcome and onset-to-reperfusion time (ORT), depending on collateral status.

METHODS

This was a retrospective analysis of clinical and imaging data of 554 consecutive patients, who had recanalisation success by EVT for anterior circulation large artery occlusion, from the prospectively maintained registries of 16 comprehensive stroke centres between September 2010 and December 2015. The patients were dichotomised into good and poor collateral groups, based on CT angiography. We tested whether the likelihood of good outcome (modified Rankin Scale, 0-2) by ORT was different between two groups.

RESULTS

ORT was 298 min±113 min (range, 81-665 min), and 84.5% of patients had good collaterals. Age, diabetes mellitus, previous infarction, National Institutes of Health Stroke Scale, good collaterals (OR 40.766; 95% CI 10.668 to 155.78; p<0.001) and ORT (OR 0.926 every 30 min delay; 95% CI 0.862 to 0.995; p=0.037) were independently associated with good outcome. The drop in likelihood of good outcome associated with longer ORT was significantly faster in poor collateral group (OR 0.305 for every 30 min; 95% CI 0.113 to 0.822) than in good collateral group (OR 0.926 for every 30 min; 95% CI 0.875 to 0.980).

CONCLUSIONS

Earlier successful recanalisation was strongly associated with good outcome in poor collateral group; however, this association was weak during the tested time window in good collateral group. This suggests that the ORT window for good outcome can be adjusted according to collateral status.

Rescue Stenting for Failed Mechanical Thrombectomy in Acute Ischemic Stroke: A Multicenter Experience

BACKGROUND AND PURPOSE

Effective rescue treatment has not yet been suggested in patients with mechanical thrombectomy (MT) failure. This study aimed to test whether rescue stenting (RS) improved clinical outcomes in MT-failed patients.

METHODS

This is a retrospective analysis of the cohorts of the 16 comprehensive stroke centers between September 2010 and December 2015. We identified the patients who underwent MT but failed to recanalize intracranial internal carotid artery or middle cerebral artery M1 occlusion. Patients were dichotomized into 2 groups: patients with RS and without RS after MT failure. Clinical and laboratory findings and outcomes were compared between the 2 groups. It was tested whether RS is associated with functional outcome.

RESULTS

MT failed in 148 (25.0%) of the 591 patients with internal carotid artery or middle cerebral artery M1 occlusion. Of these 148 patients, 48 received RS (RS group) and 100 were left without further treatment (no stenting group). Recanalization was successful in 64.6% (31 of 48 patients) of RS group. Compared with no stenting group, RS group showed a significantly higher rate of good outcome (modified Rankin Scale score, 0-2; 39.6% versus 22.0%; P=0.031) without increasing symptomatic intracranial hemorrhage (16.7% versus 20.0%; P=0.823) or mortality (12.5% versus 19.0%; P=0.360). Of the RS group, patients who had recanalization success had 54.8% of good outcome, which is comparable to that (55.4%) of recanalization success group with MT. RS remained independently associated with good outcome after adjustment of other factors (odds ratio, 3.393; 95% confidence interval, 1.192-9.655; P=0.022). Follow-up vascular imaging was available in the 23 (74.2%) of 31 patients with recanalization success with RS. The stent was patent in 20 (87.0%) of the 23 patients. Glycoprotein IIb/IIIa inhibitor was significantly associated with stent patency but not with symptomatic intracranial hemorrhage.

CONCLUSIONS

RS was independently associated with good outcomes without increasing symptomatic intracranial hemorrhage or mortality. RS seemed considered in MT-failed internal carotid artery or middle cerebral artery M1 occlusion.

Simple Coiling versus Stent-Assisted Coiling of Paraclinoid Aneurysms: Radiological Outcome in a Single Center Study

Objective

Paraclinoid aneurysms are a group of aneurysms arising at the distal internal carotid artery. Due to a high incidence of small, wide-necked aneurysms in this zone, it is often challenging to achieve complete occlusion when solely using detachable coils, thus stent placement is often required. In the present study, we aimed to investigate the effect of stent placement in endovascular treatment of paraclinoid aneurysms.

Methods

Data of 98 paraclinoid aneurysms treated by endovascular approach in our center from August 2005 to June 2016 were retrospectively reviewed. They were divided into two groups: simple coiling and stent-assisted coiling. Differences in the recurrence and progressive occlusion between the two groups were mainly analyzed. The recurrence was defined as more than one grade worsening according to Raymond-Roy Classification or major recanalization that is large enough to permit retreatment in the follow-up study compared to the immediate post-operative results.

Results

Complete occlusion was achieved immediately after endovascular treatment in eight out of 37 patients (21.6%) in the stent-assisted group and 18 out of 61 (29.5%) in the simple coiling group. In the follow-up imaging studies, the recurrence rate was lower in the stent-assisted group (one out of 37, 2.7%) compared to the simple coiling group (13 out of 61, 21.3%) (p=0.011). Multivariate logistic regression model showed lower recurrence rate in the stent-assisted group than the simple coiling group (odds ratio [OR] 0.051, 95% confidence interval [CI] 0.005-0.527). Furthermore there was also a significant difference in the rate of progressive occlusion between the stent-assisted group (16 out of 29 patients, 55.2%) and the simple coiling group (10 out of 43 patients, 23.3%) (p=0.006). The stent-assisted group also exhibited a higher rate of progressive occlusion than the simple coiling group in the multivariate logistic regression model (OR 3.208, 95% CI 1.106-9.302).

Conclusion

Use of stents results in good prognosis not only by reducing the recurrence rate but also by increasing the rate of progressive occlusion in wide-necked paraclinoid aneurysms. Stent-assisted coil embolization can be an important treatment strategy for paraclinoid aneurysms when considering the superiority of long term outcome.

Appropriate Minimal Dose of Gadobutrol for 3D Time-Resolved MRA of the Supra-Aortic Arteries: Comparison with Conventional Single-Phase High-Resolution 3D Contrast-Enhanced MRA

BACKGROUND AND PURPOSE

The development of nephrogenic systemic fibrosis and neural tissue deposition is gadolinium dose-dependent. The purpose of this study was to determine the appropriate minimal dose of gadobutrol with time-resolved MRA to assess supra-aortic arterial stenosis with contrast-enhanced MRA as a reference standard.

MATERIALS AND METHODS

Four hundred sixty-two consecutive patients underwent both standard-dose contrast-enhanced MRA and low-dose time-resolved MRA and were classified into 3 groups; group A (a constant dose of 1 mL for time-resolved MRA), group B (2 mL), or group C (3 mL). All studies were independently evaluated by 2 radiologists for image quality by using a 5-point scale (from 0 = failure to 4 = excellent), grading of arterial stenosis (0 = normal, 1 = mild [<30%], 2 = moderate [30%-69%], 3 = severe to occlusion [≥70%]), and signal-to-noise ratio.

RESULTS

The image quality of time-resolved MRA was similar to that of contrast-enhanced MRA in groups B and C, but it was inferior to contrast-enhanced MRA in group A. For the grading of arterial stenosis, there was an excellent correlation between contrast-enhanced MRA and time-resolved MRA (R = 0.957 for group A, R = 0.988 for group B, R = 0.991 for group C). The SNR of time-resolved MRA tended to be lower than that of contrast-enhanced MRA in groups A and B. However, SNR was higher for time-resolved MRA compared with contrast-enhanced MRA in group C.

CONCLUSIONS

Low-dose time-resolved MRA is feasible in the evaluation of supra-aortic stenosis and could be used as an alternative to contrast-enhanced MRA for a diagnostic technique in high-risk populations.

Metastatic Intracranial Hemangiopericytoma to the Spinal Column: A Case Report

Intracranial hemangiopericytoma (HPC) is a rare brain tumor with aggressive biologic behavior associated with high recurrence rate and often with extracranial metastasis. The most common sites of extracranial metastasis of the intracranial HPC are the long bones, lung, liver and abdominal cavity in the order of frequencies. Extracranial metastases usually occur long after the initial diagnosis of the primary tumor. Metastatic intracranial HPC to the vertebra has been rarely reported. We present a case of intracranial HPC metastasized to the L2 vertebral body 13 years after multiple surgical resections and radiotherapy of the primary intracranial HPC.

Relationship between Gyrus Rectus Resection and Cognitive Impairment after Surgery for Ruptured Anterior Communicating Artery Aneurysms

OBJECTIVE

The gyrus rectus (GR) is known as a non-functional gyrus; hence, its resection is agreed to be a safe procedure frequently practiced to achieve a better surgical view during specific surgeries. This study aimed at comparing the cognitive outcomes following GR resection in patients who underwent surgery for ruptured anterior communicating artery (ACoA) aneurysms.

MATERIALS AND METHODS

From 2012 to 2015, 39 patients underwent surgical clipping for ruptured ACoA aneurysms. Mini-mental state examinations (MMSE) were performed in 2 different periods. The statistical relationship between GR resection and MMSE results was evaluated, and further analysis of MMSE subgroup was performed.

RESULTS

Twenty-five out of the 39 patients (64.19%) underwent GR resection. Mean initial and final MMSE scores in the GR resection group were 16.3 ± 9.8 and 20.8 ± 7.3, respectively. In the non-resection group, the mean initial and final MMSE scores were 17.1 ± 8.6 and 21.9 ± 4.5, respectively. Neither group's scores showed a significant change. Subgroup analysis of initial MMSE showed a significant difference in memory recall and language (p = 0.02) but not in the final MMSE scores.

CONCLUSION

There was no significant relationship between the GR resection and cognitive outcomes in terms of total MMSE scores after surgery for ruptured ACoA aneurysm. However, subgroup analysis revealed a temporary negative effect of GR resection in the categories of language and memory recall. This study suggests that GR resection should be executed superficially, owing to its close anatomical relationship with the limbic system.

Craniosynostosis : Updates in Radiologic Diagnosis

The purpose of this article is to review imaging findings and to discuss the optimal imaging methods for craniosynostosis. The discussion of imaging findings are focused on ultrasonography, plain radiography, magnetic resonance imaging and computed tomography with 3-dimensional reconstruction. We suggest a strategy for imaging work-up for the diagnosis, treatment planning and follow-up to minimize or avoid ionized radiation exposure to children by reviewing the current literature.

Radiologic and Pathologic Findings of a Follicular Variant of Papillary Thyroid Cancer with Extensive Stromal Fat: A Case Report

Thyroid cancer may have small adipose structures detected by microscopy. However, there are no reports of thyroid cancer with gross fat evaluated by radiological methods. We reported a case of a 58-year-old woman with a fat containing thyroid mass. The mass was hyperechoic and ovoid in shape with a smooth margin on ultrasonography. On computed tomography, the mass had markedly low attenuation suggestive of fat, and fine reticular and thick septa-like structures. The patient underwent a right lobectomy. The mass was finally diagnosed as a follicular variant of papillary thyroid cancer with massive stromal fat.

Charcoal-induced granuloma that mimicked a nodal metastasis on ultrasonography and FDG-PET/CT after neck dissection

Charcoal can be used for preoperative localization of metastatic lymph nodes in the neck. Charcoal remains stable without causing foreign body reactions during as hort period. However, foreign body reactions may develop if charcoal is left in situ for more than 6 months. We reported a case of charcoal granuloma mimicking local recurrence on fluorodeoxyglucose-positron emission tomography/computed tomography and ultrasonography in a 47-year-old woman who had cervical lymph node dissection due to metastatic invasive ductal carcinoma of the breast.

Recurrent posterior circulation infarction caused by anomalous occipital bony process in a young patient

Background

Structural anomaly of the cervical spine or craniocervical junction has been reported as one of the rare causes of ischemic stroke. We report a case of a young patient with recurrent posterior circulation infarction that may have been associated with an anomalous occipital bony process compressing the vertebral artery.

Case presentation

A 23-year-old man experienced recurrent posterior circulation infarction 5 times over a period of 5 years. He had no conventional vascular risk factors. Young age stroke work-up including thorough cardiac, intra- and extracranial vascular evaluation and laboratory tests for the hypercoagulable state or connective tissue disease yielded unremarkable results. An anomalous bony process from the occipital base compressing the left vertebral artery was observed on brain CT. All the recurrent strokes were explainable by the arterial thromboembolism originating from the compressed left vertebral artery. Therefore, the left vertebral artery compressed by the anomalous occipital bony process may have been the culprit behind the recurrent thromboembolic strokes in our patient. Intractable recurrent strokes even under optimal medical treatment led us to make a decision for the intervention. Instead of surgical removal of the anomalous occipital bony process, the left vertebral artery was occluded permanently by endovascular coiling after confirming that this would cause no neurological deficits or flow disturbance in the posterior circulation. There was no recurrence of stroke for 2 years after permanent occlusion of the left vertebral artery.

Conclusion

Arterial thromboembolism originating from the left vertebral artery compressed by the anomalous occipital bony process is a rare but not to be overlooked cause of posterior circulation infarction. When intractable to medical treatment, endovascular occlusion of the vertebral artery without flow disturbance to the posterior circulation may be a useful treatment option when surgical removal is not feasible.

Clinical characteristics of cerebral venous thrombosis in a single center in Korea

OBJECTIVE

The purpose of this study is to investigate the clinical characteristics of cerebral venous thrombosis (CVT) in a single center in Korea.

METHODS

A total of 36 patients were diagnosed with CVT from August 2005 to May 2013. The patient data regarding age, sex, disease stage, pathogenesis, location, laboratory findings, radiological findings, and treatment modalities were retrospectively collected. The results were compared with those of previous studies in other countries.

RESULTS

The patient group comprised 21 men and 15 women with a mean age of 46.9 years (ranging from three months to 77 years). The most common cause was a prothrombotic condition (8 patients, 22.2%). Within the patient group, 13 patients (36.1%) had a hemorrhagic infarction, whereas 23 (63.9%) had a venous infarction without hemorrhage. By location, the incidence of hemorrhagic infarction was the highest in the group with a transverse and/or sigmoid sinus thrombosis (n=9); however, the proportion of hemorrhagic infarction was higher in the cortical venous thrombosis group (75%) and the deep venous thrombosis group (100%). By pathogenesis, the incidence of hemorrhagic infarction was the highest in the prothrombotic group (n=6), which was statistically significant (p=0.016).

CONCLUSION

According to this study, CVT was more prevalent in men, and the peak age group comprised patients in the sixth decade. The most common cause was a prothrombotic condition. This finding was comparable with reports from Europe or America, in which CVT was more common in younger women. Hemorrhagic infarction was more common in the prothrombotic group (p=0.016) than in the non-prothrombotic group in this study.

Sudden hearing loss due to internal auditory canal metastasis of Her2-positive gastric cancer: A case report

Internal auditory canal (IAC) metastasis due to leptomeningeal carcinomatosis (LMC) from gastric cancer (GC) has rarely been reported. Early manifestation of symptoms, such as hearing loss, vertigo and facial paralysis, in cases of IAC metastasis due to LMC may facilitate the early detection of brain metastasis. To the best of our knowledge, the present study is the first to report IAC metastasis due to LMC in human epidermal growth factor receptor 2 (Her2)-positive GC. This study reports a case of an Her2-positive GC patient with LMC including IAC metastasis, who presented with acute sensorineural hearing loss, ipsilateral facial paralysis and vertigo during trastuzumab containing chemotherapy. The current study also discusses the early diagnosis and management of this complicated condition, demonstrating that clinical suspicion is key for a prompt diagnosis and proper management of LMC including IAC metastasis in Her2-positive GC.

Effect of imaging time in the magnetic resonance detection of intracerebral metastases using single dose gadobutrol

OBJECTIVE

To compare the effect of imaging time delay on the MR detection of intracerebral metastases using single dose gadobutrol.

MATERIALS AND METHODS

Twenty-one patients with intracerebral metastases underwent contrast-enhanced MR with three-dimensional T1-weighted sequence at 1 minute, 5 minutes and 10 minutes after a single dose injection of gadobutrol. One hundred index metastatic lesions (1 to 30 mm; median, 7 mm) were chosen for the analysis. For the qualitative analysis, lesion conspicuity were assessed on a 1 (worst) to 5 (best) scale of the index lesions by an expert reader. For the quantitative analysis, signal intensity (SI) of enhancing lesions and normal parenchyma was measured to determine the contrast rate (CR, %) ([postcontrast SI lesion - postcontrast SI white matter] × 100 / postcontrast SI white matter) and the enhancement rate (ER, %) ([postcontrast SI lesion - baseline SI gray matter] × 100 / baseline SI gray matter). Statistical comparisons were made between three different time delays.

RESULTS

Lesion conspicuity did not differ significantly among the three time delays (p = 0.097). Although the SI, CR and ER of lesions did not reveal any significant difference between 1 minute and 5 minutes delayed images, both the 1 minute and 5 minutes delayed images showed significantly higher CRs of lesions compared with the 10 minutes delayed images (p = 0.004 and p = 0.001, respectively).

CONCLUSION

With single dose gadobutrol, imaging time delay did not have an effect on lesion conspicuity. Both 1-minute and 5-minute-delayed imaging after gadobutrol injection appears to be effective for the detection of intracerebral metastases.

Long-term outcome of vertebral artery origin stenosis in patients with acute ischemic stroke

Background

Vertebral artery origin (VAO) stenosis is occasionally observed in patients who have acute ischemic stroke. We investigated the long-term outcomes and clinical significance of VAO stenosis in patients with acute ischemic stroke.

Methods

We performed a prospective observational study using a single stroke center registry to investigate the risk of recurrent stroke and vascular outcomes in patients with acute ischemic stroke and VAO stenosis. To relate the clinical significance of VAO stenosis to the vascular territory of the index stroke, patients were classified into an asymptomatic VAO stenosis group and a symptomatic VAO stenosis group.

Results

Of the 774 patients who had acute ischemic stroke, 149 (19.3%) of them had more than 50% stenosis of the VAO. During 309 patient-years of follow-up (mean, 2.3 years), there were 7 ischemic strokes, 6 hemorrhagic strokes, and 2 unknown strokes. The annual event rates were 0.97% for posterior circulation ischemic stroke, 4.86% for all stroke, and 6.80% for the composite cardiovascular outcome. The annual event rate for ischemic stroke in the posterior circulation was significantly higher in patients who had symptomatic VAO stenosis than in patients who had asymptomatic stenosis (1.88% vs. 0%, p = 0.046). In a multivariate analysis, the hazard ratio, per one point increase of the Essen Stroke Risk Score (ESRS) for the composite cardiovascular outcome, was 1.46 (95% CI, 1.02-2.08, p = 0.036).

Conclusions

Long-term outcomes of more than 50% stenosis of the VAO in patients with acute ischemic stroke were generally favorable. Additionally, ESRS was a predictor for the composite cardiovascular outcome. Asymptomatic VAO stenosis may not be a specific risk factor for recurrent ischemic stroke in the posterior circulation. However, VAO stenosis may require more clinical attention as a potential source of recurrent stroke when VAO stenosis is observed in patients who have concurrent ischemic stroke in the posterior circulation.

Extremely delayed brain metastasis from renal cell carcinoma

Brain metastasis occurs in 3.9-24% of patients with renal cell carcinoma (RCC), with an average interval from nephrectomy to brain metastasis of 1 to 3 years. A few cases have been reported where brain metastasis occurred after a delay of more than 10 years from the initial onset of renal cell carcinoma. This long interval for central nervous system metastasis from the primary cancer has been recognized as an indicator of better prognosis. Histopathological confirmation and aggressive treatment must be considered in these delayed brain metastases cases, since the patients usually show long survival and good prognosis. We present a case of a 76-year-old woman who developed extremely late multiple brain metastases 18 years after a nephrectomy for RCC.

Primary intracranial fibrosarcoma presenting with hemorrhage

Primary intracranial fibrosarcomas (PIFs) are extremely rare and the origin of these tumors is still controversial. The rarity of primary intracranial fibrosarcomas makes it difficult to diagnose them correctly and establish a standard treatment. The pathologic diagnosis is made by distinguishing findings from light microscopic and immunohistochemistry analysis. PIFs have been known to be very aggressive neoplasms. The extra-axial location of the tumor could provide an opportunity to perform a total resection even if it does not mean a cure. We present a case of PIFs mimicking a falx meningioma in a 17-year-old man.

Comparative Results of the Patients with Intracerebral and Intra-sylvian Hematoma in Ruptured Middle Cerebral Artery Aneurysms

Objective

To clarify the prognosis of the patients with intra-sylvian hematoma (ISH) and intracerebral hematoma (ICH) in ruptured middle cerebral artery (MCA) aneurysms.

Methods

We categorized hematoma into ISH and ICH by the presence of intra-hematomal contrast enhancing vessel (IHCEV) on computed tomography angiography (CTA). Forty-four ruptured MCA aneurysm patients with ICH or ISH were grouped by the grading system proposed by the authors in our previous study. We investigated the relevance of the following factors: patient's age, gender, Hunt-Hess grade, Glasgow outcome scale (GOS) and changes in Glasgow coma scale (GCS) between pre-operation and 7 days after operation.

Results

There were no significant differences statistically in age, gender, Hunt-Hess grade, and GOS between the ISH and ICH groups. In their peri-operative GCS change, the ICH group showed greater improvement compared to the ISH group (p = 0.0391). The hematoma grade had a significant relevance with the patients' GOS.

Conclusion

Although there were no significant statistic differences in the GOS of the 2 hematoma groups, there were prominent improvements of post-operative GCS in the ICH group. Unlike in the ISH group, effective removal of hematoma was possible in most patients of the ICH group. Thus although there is no difference in the prognosis of the 2 groups, early surgical evacuation of hematoma seems to be effective in improving the short-term GCS score in peri-operative period.

Recanalization of acute intracranial artery occlusion using temporary endovascular bypass technique

PURPOSE

The purpose of this study is to present our preliminary experience of the temporary endovascular bypass (TEB) technique using an Enterprise stent for recanalization of acute intracranial artery (IA) occlusion.

MATERIALS AND METHODS

Patients treated by TEB were enrolled in this retrospective study from January 2009 to May 2010. All the procedures consist of temporary partial deployment and subsequent retrieval of Enterprise stent, supplemented by intra-arterial infusion of urokinase (UK) and/or tirofiban. According to the thrombolysis in cerebral infarction (TICI) classification, recanalization was evaluated with initial and postprocedural angiography. Safety was evaluated related to the procedure and clinical outcomes were assessed by National Institute of Health Stroke Scale (NIHSS) score at discharge and modified Rankin scale (mRS) score at 3 months.

RESULTS

Eleven patients (median NIHSS 12.8, mean age 61.6 years, male: female = 8:3) with acute IA occlusion were treated with TEB. All the patients presented with TICI 0, and the occluded vessel was the middle cerebral artery (n=7), the basilar artery (n=1), and the distal ICA occlusion (n = 3). IV infusion of tissue plasminogen activator (tPA) was done in 4 patients and mechanical thrombolysis with intra-arterial UK was performed in 9. Recanalization was achieved in 73% (8 patients; TICI ≥ 2). There were no procedure-related complications except for two asymptomatic intracranial hemorrhages. Improvement (≥ 4 points on the NIHSS) and good outcome (mRS ≤2) after 90 days was shown in six patients (55%). One patient died 6 days after procedure.

CONCLUSION

TEB may be a valuable treatment option in acute thromboembolic IA occlusion without stent implantation.

Fluid-attenuated inversion recovery hypointensity of the pulvinar nucleus of patients with Alzheimer disease: its possible association with iron accumulation as evidenced by the t2(*) map

OBJECTIVE

We hypothesized that prominent pulvinar hypointensity in brain MRI represents the disease process due to iron accumulation in Alzheimer disease (AD). We aimed to determine whether or not the pulvinar signal intensity (SI) on the fluid-attenuated inversion recovery (FLAIR) sequences at 3.0T MRI differs between AD patients and normal subjects, and also whether the pulvinar SI is correlated with the T2(*) map, an imaging marker for tissue iron, and a cognitive scale.

MATERIALS AND METHODS

Twenty one consecutive patients with AD and 21 age-matched control subjects were prospectively included in this study. The pulvinar SI was assessed on the FLAIR image. We measured the relative SI ratio of the pulvinar to the corpus callosum. The T2(*) values were calculated from the T2(*) relaxometry map. The differences between the two groups were analyzed, by using a Student t test. The correlation between the measurements was assessed by the Pearson's correlation test.

RESULTS

As compared to the normal white matter, the FLAIR signal intensity of the pulvinar nucleus was significantly more hypointense in the AD patients than in the control subjects (p < 0.01). The pulvinar T2(*) was shorter in the AD patients than in the control subjects (51.5 ± 4.95 ms vs. 56.5 ± 5.49 ms, respectively, p = 0.003). The pulvinar SI ratio was strongly correlated with the pulvinar T2(*) (r = 0.745, p < 0.001). When controlling for age, only the pulvinar-to-CC SI ratio was positively correlated with that of the Mini-Mental State Examination (MMSE) score (r = 0.303, p < 0.050). Conversely, the pulvinar T2(*) was not correlated with the MMSE score (r = 0.277, p = 0.080).

CONCLUSION

The FLAIR hypointensity of the pulvinar nucleus represents an abnormal iron accumulation in AD and may be used as an adjunctive finding for evaluating AD.

Retrograde stent placement for coil embolization of a wide-necked posterior inferior cerebellar artery aneurysm

Wide-necked aneurysms of the posterior inferior cerebellar artery (PICA) are infrequently encountered in cerebrovascular practice, and endovascular treatment is difficult or impossible even with the use of several neck remodeling techniques. We present the case of a patient with a wide-necked aneurysm of the PICA, which was treated by the retrograde stenting through the contralateral vertebral artery and vertebrobasilar junction with antegrade coil embolization.

Thyroid incidentaloma detected by time-resolved magnetic resonance angiography at 3T: prevalence and clinical significance

OBJECTIVE

To determine the prevalence of thyroid incidentalomas detected by time-resolved magnetic resonance angiography (TRMRA) and to evaluate their clinical significance by using an ultrasonographic (US) and cytologic correlation.

MATERIALS AND METHODS

We retrospectively reviewed 2010 consecutive TRMRA examinations performed at our institution between August 2006 and April 2010. The TRMRA findings of thyroid incidentalomas were analyzed according to location, size, as well as vascularity, and were correlated with the US findings and cytologic results. Each nodule was classified as suspiciously malignant, indeterminate or probably benign according to the US criteria recommended by the Korean Society of Thyroid Radiology.

RESULTS

A total of 102 incidentalomas were detected in 90 of 2010 patients (5%). TRMRA showed homogenous hypervascularity in 48 (47%), inhomogeneous hypervascularity in 46 (45%), and hypovascularity in 8 (8%) thyroid nodules. At follow-up study, out of 26 patients with 30 incidentalomas on TRMRA, 27 nodules were identified on US. Of the 27 nodules, 24 (89%) nodule were classified as indeterminate, two (7%) as probably benign, and one (4%) as suspiciously malignant. Among the 16 nodules with available cytopathologic results, 14 (82%) were benign, one (6%) was indeterminate, and one (6%) was malignant.

CONCLUSION

Thyroid incidentalomas are found in 5% of TRMRA examinations. Although their presence does not necessarily indicate malignancy, nonspecific findings of detected incidentalomas on TRMRA require further evaluation by US.

Stenting from the vertebral artery to the posterior inferior cerebellar artery

BACKGROUND AND PURPOSE

There are only a few reports on the feasibility and safety of stents used in the PICA, and clinical and angiographic follow-up results have not been fully addressed. We report our experiences of treating PICA origin or vertebral artery-PICA lesions by using self-expanding stents as adjuvant or rescue therapy with angiographic and clinical follow-up results.

MATERIALS AND METHODS

Six patients were treated with self-expanding stent placements from the vertebral artery to the PICA. Two patients had a vertebral artery dissecting aneurysm involving the PICA origin, 3 had vertebral artery-PICA aneurysms, and 1 had segmental stenosis of the vertebral artery harboring the origin of the PICA. The safety, feasibility, and follow-up angiographic results were retrospectively evaluated.

RESULTS

All procedures were successfully performed without any procedure-related complications. None of the patients showed PICA territorial infarction on DWI posttreatment. All patients were neurologically intact during the clinical follow-up of 3-24 months following the procedure. Follow-up angiography was performed at between 6 and 12 months in 5 of the 6 patients and was scheduled for the sixth patient but was not performed. The PICA showed good patency without in-stent stenosis in all 5 patients.

CONCLUSIONS

In patients with lesions of the PICA origin or vertebral artery-PICA lesions, vertebral artery-to-PICA stent placement may be an option for preserving PICA patency in selected cases.

Time-resolved 3D contrast-enhanced MRA on 3.0T: a non-invasive follow-up technique after stent-assisted coil embolization of the intracranial aneurysm

Objective

To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA.

Materials and Methods

TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method.

Results

The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively.

Conclusion

4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.

Intracranial dermoid cyst ruptured into the membranous labyrinth causing sudden sensorineural hearing loss: CT and MR imaging findings

A ruptured dermoid cyst is rare and can present with various symptoms. We report imaging findings of an intracranial dermoid cyst that ruptured into the endolymphatic sac, causing sudden sensorineural hearing loss.

Optimization of MR Parameters of 3D TOF-MRA for Various Intracranial Stents at 3.0T MRI

Purpose

The in-stent signal reduction of the stented artery caused by susceptibility artifact or radiofrequency shielding artifact limited the use of time-of-flight MR angiography (TOF-MRA) as a follow-up tool after intracranial stenting. We showed the degree of an artifact according to different stent types, and optimized MR parameters for TOF-MRA in patients with intracranial stent on 3.0 T MRI.

Materials and Methods

Four stents (Neuroform, Wingspan, Solitaire, and Enterprise) were placed in a vascular flow phantom and imaged by changing flip angle (FA; 20°,30°,40°,50° and 60°) and bandwidth (BW; 31, 42 and 62.5 KHz) using TOF-MRA. Source data of each image set with different FA and BW were reconstructed with the maximal intensity projection (MIP) technique, and MIP images were used to evaluate the in-stent signal reduction of each stent according to the change of MR parameters. The in-stent signal reduction was assessed by calculating the relative in-stent signal (RIS) inside the stent as compared with background and signal intensity of the tube outside the stent. The optimal FA and BW of each stent were determined by comparing the RIS in each stent by one-sample t test. Finally, one neuroradiologist chose one image set with the best image quality.

Results

The mean RIS for Neuroform, Wingspan, Solitaire and Enterprise stent was 66.3 ± 6.0, 44.2 ± 5.8, 22.8 ± 3.3 and 8.2 ± 2.9, respectively. The significantly high RIS of each stent was obtained with FA/BW value of 20°/31 KHz (Neuroform), 20°/31 KHz and 30°/42 KHz (Wingspan), 40°/42 KHz and 50°/31 KHz (Solitaire) and 40°/31 KHz and 50°/31 KHz (Enterprise). Among these MIP images with significantly high RIS, images with FA/BW value of 20°/31 KHz (Neuroform and Wingspan) and 50°/31 KHz (Solitaire and Enterprise) had the best image quality.

Conclusion

The degree of artifact was variable according to the design of each intracranial stent. The luminal visualization of closed-cell design stents such as Solitaire and Enterprise can be improved by higher FA. Thus, MR parameter should be adjusted according to the type of intracranial stents.

Imaging parameters of high grade gliomas in relation to the MGMT promoter methylation status: the CT, diffusion tensor imaging, and perfusion MR imaging

INTRODUCTION

We hypothesized that methyl-guanine methyl transferase (MGMT) promoter methylation status, a predictor of the chemosensitivity for high grade gliomas (HGGs), may be associated with computed tomography (CT)/magnetic resonance (MR) imaging variables.

METHODS

Out of 38 consecutive patients with HGGs, 24 patients whose MGMT promoter methylation status was available [12 men and 12 women; median age, 49 years; age range, 22-79 years; WHO grade III (n = 7), WHO grade IV (n = 17)] were enrolled retrospectively. CT attenuation, apparent diffusion coefficient (ADC), fractional anisotropy (FA), and relative cerebral blood volume (rCBV) were measured for enhancing tumors. Qualitative imaging features were also analyzed. Mann-Whitney and Fisher's exact tests were used to evaluate relationships between MGMT promoter methylation status and imaging variables.

RESULTS

Maximum CT attenuation was significantly lower in the methylated MGMT promoter group than that in the unmethylated MGMT promoter group (30.3 ± 9.5 HU versus 39.2 ± 4.7 HU, respectively, p = 0.009). While ADC values tended to be higher in the methylated group than in the unmethylated group (p = 0.055), ADC ratio was significantly higher, and the FA and FA ratios were significantly lower in the methylated group than in the unmethylated group (p = 0.032, p = 0.006 and p = 0.007, respectively). In contrast, rCBV ratio did not differ between the two groups (p = 0.380). Regarding imaging features, only ill-defined margin was seen more frequently in the methylated group than in the unmethylated group (45.5% versus 7.7%, respectively, p = 0.048).

CONCLUSION

Preoperative imaging can predict MGMT promoter methylation status, which is of paramount importance for predicting treatment response to chemotherapy with an alkylating agent.

Myocardial bridging of the left anterior descending coronary artery: depiction rate and morphologic features by dual-source CT coronary angiography

Objective

To evaluate the depiction rate and morphologic features of myocardial bridging (MB) of the left anterior descending coronary artery (LAD) using dual-source CT (DSCT).

Materials and Methods

CT scans from a total of 1,353 patients who underwent DSCT were reviewed retrospectively for LAD-MB. Seventy-eight patients were excluded due to poor image quality or poor enhancement of the coronary artery. The length and depth of the MB were analyzed and classified as superficial or deep with respect to the depth (≤ 1 or > 1 mm) of the LAD tunneled segment. Superficial MB was subdivided into complete or incomplete types according to full or partial encasement of the myocardium.

Results

Of the 1,275 patients included in this study, 557 cases of MB were found from 536 patients (42%). Superficial MB was observed in 368 of 557 (66%) cases, and deep MB was seen in 189 of 557 (34%) cases. Superficial MB showed 2 types: complete (128 of 368, 35%) and incomplete (240 of 368, 65%). The mean length of a tunneled segment for superficial MB was 16.4 ± 8.6 mm. The mean length and depth of a tunneled segment for deep MB were 27.6 ± 12.8 mm and 3.0 ± 1.4 mm, respectively. The incidence of atherosclerotic plaques in a 2-cm-long segment proximal to MB was 16%.

Conclusion

The depiction rate of LAD-MB using DSCT in a large series of patients was 42%, with two-thirds of MB segments being the superficial type.