Background and Purpose-Intracranial fusiform aneurysms can be divided into 2 clinically different subtypes: acute dissecting aneurysms and chronic fusiform or dolichoectatic aneurysms. Of these 2, the natural history and growth mechanism of chronic fusiform aneurysms remains unknown. Methods-A consecutive series of 16 patients with chronic fusiform aneurysms was studied retrospectively to clarify patient clinical and neuroradiological features. Aneurysm tissues were obtained from 8 cases and were examined to identify histological features that could correspond to the radiological findings. Results-Four histological features were found: (1) fragmentation of internal elastic lamina (IEL), (2) neoangiogenesis within the thickened intima, (3) intramural hemorrhage (IMH) and thrombus formation, and (4) repetitive intramural hemorrhages from the newly formed vessels within thrombus. IEL fragmentation was found in all cases, which suggests that this change may be one of the earliest processes of aneurysm formation. MRI or CT detected IMH, and marked contrast enhancement of the inside of the aneurysm wall (CEI) on MRI corresponded well with intimal thickening. Eight of 9 symptomatic cases but none of 7 asymptomatic cases presented with both radiological features. Conclusions-Data suggest that chronic fusiform aneurysms are progressive lesions that start with IEL fragmentation.Formation of IMH seems to be a critical event necessary for lesions to become symptomatic and progress, and this can be monitored on MRI. Knowledge of this possible mechanism of progression and corresponding MRI characteristics could help determine timing of surgical intervention. (Stroke. 2000;31:896-900.)

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AAV ANCA-associated vasculitis ACR American College of Rheumatology ADA adalimumab ANCA anti-neutrophil cytoplasmic antibody AZA azathioprine bDMARDs biologic disease-modifying anti-rheumatic drugs c-ANCA cytoplasmic ANCA CG cryoglobulin CHCC Chapel Hill Consensus Conference Cr creatinine CT computed tomography CRP C-reactive protein CyA cyclosporine CV cryoglobulinemic vasculitis CY cyclophosphamide DMARDs disease-modifying anti-rheumatic drugs * a The aorta and its primary branches corresond to the aorta (ascending, arch, thoracic descending, abdominal descending), primary branches of the aorta (including the coronary artery), and pulmonary artery. * b Multiple lesions are defined as those that involve two or more of the above arteries or sites or two or more segments of the aorta. * c Hypertrophic lesions are detected by ultrasonography (macaroni sign of the common carotid artery), contrast-enhanced CT, contrastenhanced MRI (circumferential contrast enhancement of the arterial wall), and PET-CT (circumferential FDG uptake of the arterial wall). * d Stenotic lesions and dilated lesions are detected by chest radiography (wave-like deformation of the descending aorta), CT angiography, MR angiography, echocardiography (aortic insufficiency), and angiography. They are accompanied by dilatation of the ascending aorta and frequently also by aortic insufficiency. In the chronic stage, circumferential calcification of the arterial wall is visualized by CT, and the development of collateral circulation is detected by CT angiography and MR angiography Points of attention in imaging diagnosis: Contrast-enhanced CT is performed in the late phase of contrast enhancement. CT angiography is performed in the early phase of contrast enhancement with 3-dimensional image processing. Angiography is usually performed when other procedures such as endovascular treatment and coronary artery angiography or left ventriculography are simultaneously intended. C. Conditions to be included in the differential diagnoses of Takayasu arteritis Arteriosclerosis, congenital vascular anomaly, inflammatory abdominal aortic aneurysm, infectious aneurysm, syphilitic mesaortitis, giant cell arteritis (temporal arteritis), vascular Behçet's disease, IgG4-related diseases. Definite: At least 1 of the items in A + any of the conditions in B are observed, and conditions in C can be excluded.

Abstract. Despite the prognostic importance of mitotic count as one of the components of the Bloom -Richardson grade [3], several studies [2, 9, 10] have found that pathologists' agreement on the mitotic grade is fairly modest. Collecting a set of more than 4,200 candidate mitotic figures, we evaluate pathologists' agreement on individual figures, and train a computerized system for mitosis detection, comparing its performance to the classifications of three pathologists. The system's and the pathologists' classifications are based on evaluation of digital micrographs of hematoxylin and eosin stained breast tissue. On figures where the majority of pathologists agree on a classification, we compare the performance of the trained system to that of the individual pathologists. We find that the level of agreement of the pathologists ranges from slight to moderate, with strong biases, and that the system performs competitively in rating the ground truth set. This study is a step towards automatic mitosis count to accelerate a pathologist's work and improve reproducibility.

prolonged steroid therapy may play a major role in accelerating atherosclerosis, which can result in aortic aneurysmal enlargement, possibly together with primary aortic wall involvement and/or vasculitic damage in patients with SLE.