Correction to: Percutaneous ozone nucleolysis for lumbar disc herniation The published version of this article unfortunately contained a mistake. Affiliation 2 was presented incorrectly in the original article. The updated affiliation is Neuroradiology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy.

European Society of Neuroradiology (ESNR)

Dural venous sinus stenting as a stand-alone treatment for spontaneous skull base CSF leak secondary to venous pseudotumor cerebri syndrome Abstract Most spontaneous CSF leaks (SCSFL) are associated with an underlying pseudotumor cerebri syndrome (PTCS). Treatment generally includes surgical leak repair and PTCS correction, as untreated PTCS carries a risk of recurrence. We describe a 72-year-old woman with rhinorrhea, aural fullness, and posterior nasal drip. CT and MRI showed signs of CSF hypovolemia and PTCS, as well as bilateral transverse sinus stenoses. CT and MRI cisternography documented CSF leaks through the right cribriform plate and the posterior aspect of the petrous bone. Opening CSF pressure was 6 cm H2O. Dural venous sinus stenting (DVSS) was performed after failed conservative treatment. Rhinorrhea resolved 3 days after stenting, aural fullness 1 month later. After 6 months, signs of CSF hypovolemia had disappeared on MRI and the stents were patent. After 9 months, the patient had a transient, spontaneously resolving episode of rhinorrhea. She has been symptom-free for the remaining 39 months of follow-up.

Suitability of intravascular imaging for assessment of cerebrovascular diseases Abstract Purpose Arteriosclerosis of the vascular system is associated with many accompanying diseases. Especially cerebral arteriosclerosis is a main risk factor for ischemic strokes. We want to verify the practicability of intravascular imaging like intravascular ultrasound and optical coherence tomography for the assessment of cerebral vessel walls and plaques. Methods We examined 18 Circuli arteriosi willisii postmortem. The data contained 48 plaques from 48 different vessel parts. The samples underwent intravascular and histological imaging to conduct a quantitative assessment of vessel wall parameters (healthy vessel wall, thinnest vessel wall, plaque thickness and vessel diameter) as well as to qualitatively evaluate the healthy vessel wall, fibrotic plaques, calcifications and cholesterol deposits in diseased vessels. Results The comparison showed statistically significant smaller measurements for thinnest vessel walls, normal vessel walls and vessel diameters in histology than in imaging. No statistically significant difference was reached for plaque diameters. Fibrotic plaques were characterized as hyper-intense with dorsal attenuation and calcifications as hypo-intense with dorsal attenuation in optical coherence tomography. In intravascular ultrasound, fibrotic plaques showed a homogeneous echogenicity without distal attenuation and calcifications were depicted as hyperechoic with dorsal sound shadows. Cholesterol deposits were hyper-intense in optical coherence tomography with strongly attenuated signals and in intravascular ultrasound; the deposits were hyper-intense with almost no attenuation. Conclusion Both intravascular methods allow for plaque characterization and quantification of plaque diameter in cerebral vessel walls. When compared with histology, a statistically significant bias was obtained for the ex vivo measurements of the normal vessel wall diameters.

MR imaging phenotype correlates with extent of genome-wide copy number abundance in IDH mutant gliomas Abstract Purpose There is variability in survival within IDH mutant gliomas determined by chromosomal events. Copy number variation (CNV) abundance associated with survival in low-grade and IDH mutant astrocytoma has been reported. Our purpose was to correlate the extent of genome-wide CNV abundance in IDH mutant astrocytomas with MRI features. Methods Presurgical MRI and CNV plots derived from Illumina 850k EPIC DNA methylation arrays of 18 cases of WHO grade II–IV IDH mutant astrocytomas were reviewed. IDH mutant astrocytomas were divided into CNV stable group (CNV-S) with ≤ 3 chromosomal gains or losses and lack of focal gene amplifications and CNV unstable group (CNV-U) with > 3 large chromosomal gains/losses and/or focal amplifications. The associations between MR features, relative cerebral blood volume (rCBV), CNV abundance, and time to progression were assessed. Tumor rCBV estimates were obtained using DSC T2* perfusion analysis. Results There were nine (50%) CNV-S and nine (50%) CNV-U IDH mutant astrocytomas. CNV-U tumors showed larger mean tumor size (P = 0.004) and maximum diameter on FLAIR (P = 0.004) and also demonstrated significantly higher median rCBV than CNV-S tumors (2.62 vs 0.78, P = 0.019). CNV-U tumors tended to have shorter time to progression although without statistical significance (P = 0.393). Conclusions Larger size/diameter and higher rCBVs were seen associated CNV-U astrocytomas, suggesting a correlation of aggressive imaging phenotype with unstable and aggressive genotype in IDH mutant astrocytomas.

Safety and efficacy of intracranial aneurysm embolization using the “combined remodeling technique”: low-profile stents delivered through double lumen balloons: a multicenter experience Abstract Purpose Since appearance of the balloon-remodeling technique and stent-assisted coiling, complex aneurysms have been treated successfully by endovascular means worldwide. Although these two techniques have been widely proven, the combination of both traditionally made the procedures more complicated technically. The aim of our study was to determine the technical success, safety, and efficacy of the low-profile stents delivered through double lumen balloons. Methods Clinical, procedural, and angiographic data were analyzed. Results Eighty-four patients (55 women; age range 20–81 years) harboring 86 aneurysms were included in this study. Aneurysm maximal diameter ranged from 2 to 26 mm, with mean 7.5 mm. There were 62 unruptured, 15 recanalized, and 9 acutely ruptured aneurysms. Aneurysm locations were ACoA (31), MCA (36), supraclinoid ICA (4), carotid bifurcation (2), basilar (7), PCA (3), PICA (2), and VA (1). Ninety-three devices were implanted (63 LVIS jr, 15 LEO Baby, 14 ACCLINO Flex and 1 Neuroform Atlas) through the double lumen balloons (Scepter C or XC and Eclipse 2 L). We found 2 minor clinical events (2.4%) and 1 major event (1.2%). Total intra-procedural technical complication rate was 11.6%. Follow-up was available for 71 patients with an average follow-up of 7 months. Complete and near complete occlusion was 90.1%. Residual aneurysms were seen in 9.9%. Conclusion The “combined remodeling technique” with low-profile stents delivered through double-lumen balloons is technically feasible, safe, and effective for the treatment of intracranial aneurysms. This technique allows the operator to avoid extra maneuvers.

Brain functional organization and structure in patients with arteriovenous malformations Abstract Purpose Developmental in nature, brain arteriovenous malformations (AVM) have the potential to affect whole brain organization. Here we investigated the impact of AVM on functional and structural brain organization using resting-state functional MRI (rsfMRI) and cortical thickness measures. Methods We investigated brain functional organization and structure using rsfMRI in conjunction with cortical thickness analyses in 23 patients with cerebral arteriovenous malformations (AVMs) and 20 healthy control subjects. Results Healthy controls showed the expected anti-correlation between activity in the default mode network (DMN) and frontal areas that are part of the attentional control network. By contrast, patients demonstrated a disruption of this anti-correlation. Disruptions to this anti-correlation were even observed in a subgroup of patients with lesions remote from the main nodes of the DMN and were unrelated to differences in perfusion. Functional connectivity differences were accompanied by reduced cortical thickness in frontal attentional areas in patients compared to the controls. Conclusions These results contribute to the discussion that AVMs affect whole brain networks and not simply the area surrounding the lesion.

Acceleration-selective arterial spin labeling MR angiography for visualization of brain arteriovenous malformations Abstract Purpose To evaluate the performance of acceleration-selective arterial spin labeling (AccASL) MR angiography in the visualization of brain arteriovenous malformations (AVMs) in comparison with digital subtraction angiography (DSA) and time-of-flight (TOF) MR angiography. Methods Twenty-one patients with brain AVM (mean age 31.1 ± 18.6 years; 11 males, 10 females) underwent TOF and AccASL MR angiography and DSA. Two neuroradiologists conducted an observer study for detection, nidus size, eloquence, venous drainage pattern, and Spetzler-Martin (SM) grade. The evaluations included the visualization of each AVM component with reference to DSA and assessments of contrast-to-noise ratio (CNR). The kappa statistic, repeated measures analysis of variance, Wilcoxon matched pairs test, and paired t test were used. Results Both observers detected more AVMs with AccASL (95.2%, 90.5% for Observers 1 and 2) than with TOF (76.2% and 71.4%, respectively). The inter-modality agreement between AccASL and DSA was almost perfect for the eloquence, venous drainage pattern, and SM grade for Observer 1 and moderate for the venous drainage pattern and substantial for the eloquence and SM grade for Observer 2. The visualization scores were higher with AccASL than with TOF for the feeding artery (AccASL, 4.5 ± 1.0 vs. TOF, 3.9 ± 1.5, p = 0.0214), nidus (4.6 ± 1.1 vs. 3.2 ± 1.5, p = 0.0006), and draining vein (4.6 ± 1.0 vs. 2.2 ± 1.1, p < 0.0001), respectively. The CNRs in the nidus were higher in AccASL than in TOF (29.9 ± 16.7 vs. 20.8 ± 16.5, p = 0.0002), as in the draining vein (23.2 ± 13.0 vs. 12.6 ± 12.0, p = 0.0010), respectively. Conclusions AccASL better visualized brain AVMs compared with TOF and was useful for grading without the use of contrast agents.

Collaterals are a major determinant of the core but not the penumbra volume in acute ischemic stroke Abstract Purpose Determinants of early loss of ischemic tissue (core) or its prolonged survival (penumbra) in acute ischemic stroke (AIS) are poorly understood. We aimed to identify radiological associations of core and penumbra volumes on CT perfusion (CTP) in a large cohort of AIS. Methods In the ASTRAL registry (2003–2016), we identified consecutive AIS patients with proximal middle cerebral artery (MCA) occlusion. We calculated core and penumbra volumes using established thresholds and the mismatch ratio (MR). We graded collaterals into three categories on CT-angiography. We used clot burden score (CBS) to quantify the clot length. We related CTP volumes to radiological variables in multivariate regression analyses, adjusted for time from stroke onset to first imaging. Results The median age of the 415 included patients was 69 years (IQR = 21) and 49% were female. Median admission NIHSS was 16 (11) and median delay to imaging 2.2 h (1.9). Lower core volumes were associated with higher ASPECTS (hazard ratio = 1.08), absence of hyperdense MCA sign (HR = 0.70), higher CBS (i.e., smaller clot, HR = 1.10), and better collaterals (HR = 1.95). Higher penumbra volumes were related to lower CBS (i.e., longer clot, HR = 1.08) and proximal intracranial occlusion (HR = 1.47), but not to collaterals. Higher MR was found in absence of hyperdense MCA sign (HR = 1.28), absence of distal intracranial occlusion (HR = 1.39), and with better collaterals (HR = 0.52). Conclusions In AIS, better collaterals were associated with lower core volumes, but not with higher penumbra volumes. This suggests a major role of collaterals in early tissue loss and their limited significance as marker of salvageable tissue.

Angioplasty and/or stenting after thrombectomy in patients with underlying intracranial atherosclerotic stenosis Abstract Purpose To investigate the imaging and clinical outcomes of emergent angioplasty and/or stenting or neither in patients of emergent large-vessel occlusion (ELVO) with underlying severe intracranial atherosclerotic stenosis (ICAS). Methods In this multicenter prospective cohort study, we included patients of ELVO with underlying ICAS. Patients received emergent angioplasty and/or stenting or neither after mechanical thrombectomy at the interventionists’ discretion. The primary outcome was recanalization rate at 24 h, which was defined as a modified arterial occlusive lesion score of 2 or 3. Results A total of 113 consecutive patients with underlying ICAS > 70% in anterior cerebral circulation were enrolled in this study. Of these, 81 (71.7%) received emergent angioplasty and/or stenting after thrombectomy. Patients in the emergent angioplasty and/or stenting group were significantly more likely to have recanalization at 24 h (adjusted OR [aOR], 3.782; 95% confidence interval [CI], 1.821–9.125; P = 0.02) and less likely to have early neurologic deterioration (aOR, 0.299; 95% CI, 0.110–0.821; P = 0.01). However, emergent angioplasty and/or stenting was not significantly associated with symptomatic intracranial hemorrhage (aOR, 0.710; 95% CI, 0.199–2.622; P = 0.67), asymptomatic intracranial hemorrhage (aOR, 1.325; 95% CI, 0.567–3.031; P = 0.81), death at 90 days (aOR, 0.581; 95% CI, 0.186–2.314; P = 0.41), and functional independence at 90 days (aOR, 1.752; 95% CI, 0.774–3.257; P = 0.16), compared with patients that received neither. Conclusion Emergent angioplasty and/or stenting is possible in patients of ELVO with ICAS and may reduce the risk of reocclusion and early neurologic deterioration with no increased risk of intracranial hemorrhage and death than those received neither.