Utility of follow-up ultra-high-resolution CT angiography with model-based iterative reconstruction after flow diverter treatment for cerebral aneurysms.

PURPOSE: Follow-up examinations after flow diverter (FD) treatment for cerebral aneurysms typically involve magnetic resonance imaging (MRI) or digital subtraction angiography (DSA). However, MRI is prone to vascular defects due to metal artifacts from FD, and DSA carries a risk of ischemic complications. In the context of computed tomography angiography (CTA), this study compares the efficacy of ultra-high-resolution CT (UHRCT) and novel reconstruction techniques, such as model-based iterative reconstruction (MBIR), against conventional methods such as filtered back projection (FBP) and hybrid iterative reconstruction (IR), to determine if they are a viable alternative to DSA in clinical settings. MATERIALS AND METHODS: A phantom study was conducted with the full-width half-maximum considered as the FD thickness. This study compared three reconstruction methods: MBIR, FBP, and hybrid IR. A clinical study was also conducted with 21 patients who underwent follow-up CTA after FD treatment. The FD's visibility was assessed using a 4-point scale in FBP, hybrid IR, and MBIR compared to cone-beam CT (CBCT) with angiographic systems. RESULTS: In the phantom study, FBP, hybrid IR, and MBIR visualized thinner FD thicknesses and improved detail rendering in that order. MBIR proved to be significantly superior in both the phantom and clinical study. CONCLUSION: UHRCT with MBIR is highly effective for follow-up evaluations after FD treatment and may become the first-choice modality in the future.

Endovascular Mechanical Thrombectomy with a Large-Bore Aspiration Catheter and Stent Retriever for Cerebral Venous Sinus Thrombosis in Pregnancy: A Case Report.

Objective: A case of cerebral venous sinus thrombosis (CVST) during pregnancy effectively recanalized by endovascular mechanical thrombectomy with the combined use of an aspiration catheter and a stent retriever is reported. Case Presentation: A 27-year-old woman at eight weeks' gestation developed sudden onset of right hemiparalysis and seizures and was referred to our hospital. Her National Institutes of Health Stroke Scale score on admission was 23. On MRI, diffusion-weighted imaging showed a hyperintensity area in the left frontal lobe, and T2* imaging showed hemorrhagic infarction in the same area. MR venography showed obstruction of the anterior two-thirds of the superior sagittal sinus (SSS). Anticoagulant therapy with heparin was started, but since the venous return was expected to be severely impaired, mechanical thrombectomy by endovascular surgery was selected, hoping to resolve symptoms early. Using a large-bore aspiration catheter in combination with a stent retriever, it was possible to safely guide the aspiration catheter into the anterior half of the SSS. The use of a large-bore aspiration catheter enabled retrieval of a large amount of thrombus in a short time, and complete recanalization was achieved. The patient's hemiplegia and aphasia improved significantly within a week after the procedure, and she was discharged without sequelae. Conclusion: Mechanical endovascular therapy of CVST performed with a combination of a large-bore aspiration catheter and a stent retriever should be considered particularly for patients with severe neurological symptoms or intracranial hemorrhage and for those who do not respond to anticoagulation therapy.

A New Method of Microcatheter Heat-Forming for Cerebral Aneurysmal Coiling Using Stereolithography Three-Dimensional Printed Hollow Vessel Models.

BACKGROUND: To perform successful coil embolization of cerebral aneurysms, it is crucial to make an appropriately shaped microcatheter tip for an aneurysm and its parent artery. So far, we manually shaped a mandrel by referencing two-dimensional (2D) images of a rotation digital subtraction angiography (DSA) on a computer screen. However, this technique requires a lot of experience, and often involves trial and error. Recently, there have been increasing reports of manual mandrel shaping using a full-scale three-dimensional (3D) model of an aneurysm and its parent artery output by various types of 3D printer. We have further developed this method by producing a hollow model of an aneurysm and its parent artery with a stereolithography 3D printer and inserting a mandrel inside the model to fit and stabilize a microcatheter tip. METHODS: Based on digital imaging and communications in medicine (DICOM) data obtained by rotational DSA, 3D images of an aneurysm and its parent artery were created and converted into standard triangulated language (STL) data. A hollow model was produced by extruding the STL data outward in the normal direction, and then a hole was made at the tip of the aneurysm using these STL data. We output these STL data to a stereolithography 3D printer. After cleaning and sterilizing the model, the mandrel was inserted in the direction of the parent artery through the hole made in the tip of the aneurysm and pushed in, creating the ideal mandrel shape. Twelve cases (14 aneurysms) were included in this study. A microcatheter tip was shaped by this method for patients who were scheduled to undergo coil embolization for an unruptured aneurysm. RESULTS: In 13 of the 14 aneurysms, the microcatheter was easily guided into the aneurysms in one or two trials, the position of the microcatheter tip in the aneurysm was appropriate, and the stability during coil embolization was high. CONCLUSION: Our method differs from the conventional one in that a hollow model made of resin is produced with a stereolithography 3D printer and that the mandrel is shaped by inserting it retrogradely into the hollow model. Using our new method, it will be possible to shape the tip of a microcatheter suitable for safe and stable coil embolization without relying on an operator's experience.

A dedifferentiated intracranial solitary fibrous tumor with osteosarcoma components: rapid tumor progression and lethal clinical course.

Solitary fibrous tumor/hemangiopericytoma is a mesenchymal tumor that originates from a common NAB2-STAT6 fusion gene and is known to very rarely demonstrate dedifferentiation in the pattern of local recurrence or distant metastasis. Here we describe for the first time a rare case of intracranial dedifferentiated solitary fibrous tumor/hemangiopericytoma with osteosarcoma components that developed in an 84-year-old man after frequent gamma knife radiosurgery over a 14-year period. We performed tumor-debulking and gamma knife radiosurgery, but unfortunately the patient died shortly after the development of dedifferentiation. There is no established treatment for dedifferentiated cases due to the rare histology and limited published data, and therefore further accumulation of histological and genetic profiles is necessary to develop novel target gene therapies.

Hydrocephalus with panventricular enlargement as the primary manifestation of neurosarcoidosis: a case report.

INTRODUCTION: Hydrocephalus is very uncommon in neurosarcoidosis. To date, there have been only five reported cases of hydrocephalus occurring as the first manifestation of neurosarcoidosis. Such a presentation in a previously healthy patient is challenging to diagnose. CASE PRESENTATION: A 31-year-old Japanese man who had no relevant past history other than sinusitis was admitted to our institution complaining of low-grade fever and mild headache. He was alert and neurologically intact. No respiratory symptoms were observed. Laboratory examination revealed mild elevation of erythrocyte sedimentation rate and serum CD4/CD8 ratio. Serum angiotensin-converting enzyme level was in the normal range. His cerebrospinal fluid showed mild pleocytosis and increased protein level. A chest X-ray revealed bihilar lymphadenopathy with normal lung parenchyma. Computed tomography of his head showed remarkable hydrocephalus with dilatation of all ventricles, particularly the fourth. Gadolinium-enhanced magnetic resonance imaging demonstrated leptomeningeal millet seed-like enhancement and multiple small enhancing lesions along the Virchow-Robin spaces. These findings strongly suggested a chronic inflammatory disease such as neurosarcoidosis. To treat the hydrocephalus, a ventriculoperitoneal shunt was inserted. The postoperative course was satisfactory. After surgery, nasal and skin biopsies were performed and pathological analysis revealed non-caseating granulomas consistent with sarcoidosis. The findings of gallium scintigraphy also supported the diagnosis of sarcoidosis. We obtained the definitive diagnosis of sarcoidosis 3 weeks after admission from the pathological findings by the nasal and skin biopsies, and corticosteroid therapy was started after that. CONCLUSION: We present a rare case of neurosarcoidosis manifesting as acute hydrocephalus with dilatation of all ventricles, particularly the fourth. As hydrocephalus due to neurosarcoidosis has high morbidity and mortality, early diagnosis and proper treatment are particularly important.