Angiosarcoma on Top of a Meningioma Mimicking a Transosseous Meningioma: an Interdisciplinary Point of View.

Cutaneous angiosarcoma is a rare type of sarcoma with poor prognosis. Meningioma is the most frequent benign intracranial tumor. Despite the fact that meningiomas are mostly benign, bone and skin can be infiltrated. We report the rare case of an angiosarcoma on top of a meningioma with hyperostosis at exactly the same location mimicking a transosseous growth of a meningioma. An 84-year-old man presented with progressive swelling and ulcerous lesion of the forehead. The patient underwent surgery in an interdisciplinary setting together with a plastic surgeon, including resection of the intracranial tumor and infiltrated bone and skin. To the best of our knowledge, this is the only reported case of a meningioma and angiosarcoma in direct neighborhood. A preoperative biopsy of the skin tumor would have led initially to the correct diagnosis of an angiosarcoma and would have allowed a better planning of the operation and extent of resection.

Occlusion Type, Number of Recanalization Passages and Dose Program Determine Radiation Dose in Endovascular Stroke Thrombectomy.

PURPOSE: Identification of independent treatment factors associated with high radiation exposure during endovascular mechanical thrombectomy (EMT) in acute ischemic stroke. METHODS: This retrospective analysis included all patients treated by means of EMT during the 2­year period 2017-2018 in a comprehensive stroke center. The EMT were performed by four internal and three external certified neuroradiologists in a clinic overlapping on call system. Radiation exposure as the dependent variable (dose area product DAP, Gy ⋅ cm2) was dichotomized in < 100 Gy ⋅ cm2 and ≥ 100 Gy ⋅ cm2. Independent variables were age (< 75 years vs. ≥ 75 years), time of intervention (during vs. beyond workday), treating neuroradiologist (internal vs. external), occlusion type ("mono" vs. "tandem"), reperfusion success (TICI 0-2A vs. TICI 2B/3), recanalization attempts (≤ 2 vs. > 2) and dose protocol (normal dose in 2017 vs. low dose in 2018). RESULTS: The EMT treatment of 208 patients (111 female, 97 male, mean age 71.6 years) was analyzed. Median DAP was 86.6 Gy ⋅ cm2 and could be reduced from 104.8 Gy ⋅ cm2 (N = 105 in 2017) to 73.3 Gy ⋅ cm2 (N = 103 in 2018) with LD program. Univariable and multivariable binary logistic regression analysis revealed a significantly increased radiation exposure (≥ 100 Gy ⋅ cm2) in tandem occlusion type (P < 0.001), > 2 recanalization attempts (P < 0.001) and normal dose protocol (P = 0.002). CONCLUSION: Low dose programs can significantly reduce the radiation exposure in EMT. High radiation exposure is significantly associated with more than two recanalization attempts and in cases of tandem occlusions.

A system to detect cerebral aneurysms in multimodality angiographic data sets.

PURPOSE: The early detection of cerebral aneurysms plays a major role in preventing subarachnoid hemorrhage. The authors present a system to automatically detect cerebral aneurysms in multimodal 3D angiographic data sets. The authors' system is parametrizable for contrast-enhanced magnetic resonance angiography (CE-MRA), time-of-flight magnetic resonance angiography (TOF-MRA), and computed tomography angiography (CTA). METHODS: Initial volumes of interest are found by applying a multiscale sphere-enhancing filter. Several features are combined in a linear discriminant function (LDF) to distinguish between true aneurysms and false positives. The features include shape information, spatial information, and probability information. The LDF can either be parametrized by domain experts or automatically by training. Vessel segmentation is avoided as it could heavily influence the detection algorithm. RESULTS: The authors tested their method with 151 clinical angiographic data sets containing 112 aneurysms. The authors reach a sensitivity of 95% with CE-MRA data sets at an average false positive rate per data set (FPDS) of 8.2. For TOF-MRA, we achieve 95% sensitivity at 11.3 FPDS. For CTA, we reach a sensitivity of 95% at 22.8 FPDS. For all modalities, the expert parametrization led to similar or better results than the trained parametrization eliminating the need for training. 93% of aneurysms that were smaller than 5 mm were found. The authors also showed that their algorithm is capable of detecting aneurysms that were previously overlooked by radiologists. CONCLUSIONS: The authors present an automatic system to detect cerebral aneurysms in multimodal angiographic data sets. The system proved as a suitable computer-aided detection tool to help radiologists find cerebral aneurysms.