Vascular Involvement in Neurosarcoidosis

Background and ObjectivesCerebrovascular manifestations in neurosarcoidosis (NS) were previously considered rare but are being increasingly recognized. We report our preliminary experience in patients with NS who underwent high-resolution vessel wall imaging (VWI).MethodsA total of 13 consecutive patients with NS underwent VWI. Images were analyzed by 2 neuroradiologists in consensus. The assessment included segment-wise evaluation of larger- and medium-sized vessels (internal carotid artery, M1-M3 middle cerebral artery; A1-A3 anterior cerebral artery; V4 segments of vertebral arteries; basilar artery; and P1-P3 posterior cerebral artery), lenticulostriate perforator vessels, and medullary and deep cerebral veins. Cortical veins were not assessed due to flow-related artifacts. Brain biopsy findings were available in 6 cases and were also reviewed.ResultsMean patient age was 54.9 years (33–71 years) with an M:F of 8:5. Mean duration between initial diagnosis and VWI study was 18 months. Overall, 9/13 (69%) patients had vascular abnormalities. Circumferential large vessel enhancement was seen in 3/13 (23%) patients, whereas perforator vessel involvement was seen in 6/13 (46%) patients. Medullary and deep vein involvement was also seen in 6/13 patients. In addition, 7/13 (54%) patients had microhemorrhages in susceptibility-weighted imaging, and 4/13 (31%) had chronic infarcts. On biopsy, 5/6 cases showed perivascular granulomas with vessel wall involvement in all 5 cases.DiscussionOur preliminary findings suggest that involvement of intracranial vascular structures may be a common finding in patients with NS and should be routinely looked for. These findings appear concordant with previously reported autopsy literature and need to be validated on a larger scale.

Multichannel Retinal Blood Vessel Segmentation Based on the Combination of Matched Filter and U-Net Network

Aiming at the current problem of insufficient extraction of small retinal blood vessels, we propose a retinal blood vessel segmentation algorithm that combines supervised learning and unsupervised learning algorithms. In this study, we use a multiscale matched filter with vessel enhancement capability and a U-Net model with a coding and decoding network structure. Three channels are used to extract vessel features separately, and finally, the segmentation results of the three channels are merged. The algorithm proposed in this paper has been verified and evaluated on the DRIVE, STARE, and CHASE_DB1 datasets. The experimental results show that the proposed algorithm can segment small blood vessels better than most other methods. We conclude that our algorithm has reached 0.8745, 0.8903, and 0.8916 on the three datasets in the sensitivity metric, respectively, which is nearly 0.1 higher than other existing methods.

Effect of vessel enhancement filters on the repeatability of measurements obtained from widefield swept-source optical coherence tomography angiography

We assessed the inter-visit repeatability of 15 × 9-mm2 swept-source OCTA (SS-OCTA; PLEX Elite 9000, Carl Zeiss Meditec) metrics in 14 healthy participants. We analysed the perfusion density (PD) of large vessels, superficial capillary plexus (SCP), and deep capillary plexus (DCP) as well as choriocapillaris flow voids in 2 different regions: the macular region and peripheral region. Also, retinal plexus metrics were processed further using different filters (Hessian, Gabor and Bayesian) while choriocapillaris flow voids were calculated with 1 and 1.25 standard deviation (SD) thresholding algorithms. We found excellent repeatability in the perfusion densities of large vessels (ICC > 0.96). Perfusion densities varied with different filters in the macular region (SCP: 24.12–38.57% and DCP: 25.16–38.50%) and peripheral (SCP: 30.52–39.84% and DCP: 34.19–41.60%) regions. The ICCs were lower in the macular region compared to the peripheral region and lower for DCP than for SCP. For choriocapillaris flow voids, the 1.25 SD threshold resulted in fewer flow voids, while a good ICC (ICC > 0.81) was achieved using either threshold settings for flow void features in both regions. Our results suggest good repeatability of widefield SS-OCTA for the measurements of retinal perfusion density and choriocapillaris flow voids, but measurements from different filters should not be interchanged.

Increased contrast enhancement of the parent vessel of unruptured intracranial aneurysms in 7T MR imaging

BackgroundInflammation of the arterial wall may lead to aneurysm formation. The presence of aneurysm enhancement on high-resolution vessel wall imaging (HR-VWI) is a marker of wall inflammation and instability. We aim to determine if there is any association between increased contrast enhancement in the aneurysmal wall and its parent artery.MethodsPatients with unruptured intracranial aneurysms (UIAs) prospectively underwent 7T HR-VWI. Regions of interest were selected manually and with a semi-automated protocol based on gradient algorithms of intensity patterns. Mean signal intensities in pre- and post-contrast T1-weighted sequences were adjusted to the enhancement of the pituitary stalk and then subtracted to objectively determine: circumferential aneurysmal wall enhancement (CAWE); parent vessel enhancement (PVE); and reference vessel enhancement (RVE). PVE was assessed over regions located 3- and 5 mm from the aneurysm’s neck. RVE was assessed in arteries located in a different vascular territory.ResultsTwenty-five UIAs were analyzed. There was a significant moderate correlation between CAWE and 5 mm PVE (Pearson R=0.52, P=0.008), whereas no correlation was found between CAWE and RVE (Pearson R=0.20, P=0.33). A stronger correlation was found between CAWE and 3 mm PVE (Pearson R=0.78, P<0.001). Intra-class correlation analysis demonstrated good reliability between measurements obtained using semi-automated and manual segmentation (ICC coefficient=0.790, 95% CI 0.58 to 0.90).ConclusionParent arteries exhibit higher contrast enhancement in regions closer to the aneurysm’s neck, especially in aneurysms≥7 mm. A localized inflammatory/vasculopathic process in the wall of the parent artery may lead to aneurysm formation and growth.

Abstract 143: Increased Contrast Enhancement of the Parent Vessel of Unruptured Intracranial Aneurysms in 7T Magnetic Resonance Imaging

Background: Aneurysm formation and growth might be explained by a local inflammatory/vasculopathic process that debilitates the wall of the parent artery. Recently, the presence of aneurysm enhancement on high-resolution vessel wall imaging (HR-VWI) has been proposed as a surrogate for vessel wall inflammation. However, no studies have correlated circumferential aneurysm wall enhancement (CAWE) and aneurysm-to-pituitary enhancement ratio (CR stalk ) on HR-VWI with parent vessel enhancement (PVE) and reference vessel enhancement (RVE). Methods: Patients with unruptured intracranial aneurysms prospectively underwent HR-VWI using 7T MRI. CAWE, CR stalk , PVE and RVE were objectively analyzed by measuring signal intensity in T1 post-contrast sequences using manual 3D co-registration and segmentation of the vessel wall. CR stalk was calculated as the ratio of post-contrast CAWE over pituitary stalk enhancement. RVE was assessed in the mid-BA for aneurysms in the anterior circulation, and the MCA (M1 segment) for posterior circulation aneurysms. Correlation statistics were performed to find any significant association between CAWE, CR stalk , PVE and RVE. Results: Nineteen patients with 20 aneurysms were included. Mean age was 68.9 ± 9.9 years old, and 16 (84.2%) were women. Pearson and Spearman coefficients’ analyses demonstrated a strong positive correlation between post-contrast CAWE and PVE (0.72 and 0.73, both P <.001), whereas the correlation between post-contrast CAWE and RVE was low (both 0.47, P =.04). A stronger correlation was found between CR stalk and post-contrast PVE (Pearson = 0.82, Spearman = 0.71, both P <.001), while the correlation between CR stalk and post-contrast RVE was negligible (Pearson = 0.33, P =.15; Spearman = 0.38, P =.09). Conclusion: This HR-VWI study shows that the parent vessel of unruptured intracranial aneurysms enhances more with contrast than vessels located in other vascular territories. This finding suggests that a local inflammatory/vasculopathic process in the wall of the parent artery may lead to aneurysm formation.