3D dissimilar-siamese-u-net for hyperdense Middle cerebral artery sign segmentation.

The hyperdense middle cerebral artery sign (HMCAS) representing a thromboembolus has been declared as a vital CT finding for intravascular thrombus in the diagnosis of acute ischemia stroke. Early recognition of HMCAS can assist in patient triage and subsequent thrombolysis or thrombectomy treatment. A total of 624 annotated head non-contrast-enhanced CT (NCCT) image scans were retrospectively collected from multiple public hospitals in Hong Kong. In this study, we present a deep Dissimilar-Siamese-U-Net (DSU-Net) that is able to precisely segment the lesions by integrating Siamese and U-Net architectures. The proposed framework consists of twin sub-networks that allow inputs of left and right hemispheres in head NCCT images separately. The proposed Dissimilar block fully explores the feature representation of the differences between the bilateral hemispheres. Ablation studies were carried out to validate the performance of various components of the proposed DSU-Net. Our findings reveal that the proposed DSU-Net provides a novel approach for HMCAS automatic segmentation and it outperforms the baseline U-Net and many state-of-the-art models for clinical practice.

Treatment of Intracranial Aneurysms with Flow Re-direction Endoluminal Device - A Single Centre Experience with Short-term Follow-up Results.

PURPOSE: A flow diverter (FD) is an effective treatment option for intracranial aneurysms. The Flow Re-direction Endoluminal Device (FRED) is a relatively new flow diverter with a unique dual-layer design. We report our experience and short-term results with the FRED. MATERIALS AND METHODS: We did a retrospective review of all consecutive cases in which the FRED was used to treat intracranial aneurysms at a single institution from March 2014 till December 2015. Clinical parameters, aneurysm characteristics, technical results and short-term outcomes were reviewed. RESULTS: Eleven intracranial aneurysms were treated with the FRED in 11 patients. The technical device deployment success rate was 100%. Immediate reduction in intra-aneurysmal flow after deployment was noted in 10 cases. The aneurysm occlusion rate at 6 months was 75%. There was 1 complication of in-stent thrombosis immediately after deployment. There was no side branch occlusion, delayed aneurysm rupture, stroke, or intraparenchymal haemorrhage. There was no neurological deficit, morbidity, or mortality. CONCLUSION: The FRED is a new FD. It has shown to be safe and effective in our series. The unique dual-layer design of the device renders it to have technical advantages over other FDs. The 6-month aneurysm occlusion rate and complication profile of FRED are similar to other FDs.

Early Enlargement of Aneurysmal Sac and Separation of EndoBags of Nellix Endovascular Aneurysm Sealing System as Signs of Increased Risk of Later Aneurysm Rupture.

Nellix Endovascular Aneurysm Sealing (EVAS) system is a new concept and technology of abdominal aortic aneurysm (AAA) repair. Elective EVAS using Nellix device was performed for a 83-year-old man with AAA. 2-month post-EVAS CTA surveillance demonstrated mild enlargement of aneurysmal sac and separation of the EndoBags, but without detectable endoleak. The patient developed sudden AAA rupture with retroperitoneal hematoma at about 4 months after EVAS. We postulated that early enlargement of aneurysmal sac and separation of EndoBags of Nellix devices after EVAS, even without detectable endoleak, might indicate significant aneurysmal wall weakening with increased risk of later AAA rupture. To the best of the authors' knowledge, this was the first reported case of aortic rupture after EVAS without detectable endoleak during and after the procedure.