Using a distance map and an active contour model to segment the carotid artery boundary from the lumen contour in proton density weighted magnetic resonance images.

Segmentation methods have assumed an important role in image-based diagnosis of several cardiovascular diseases. Particularly, the segmentation of the boundary of the carotid artery is demanded in the detection and characterization of atherosclerosis and assessment of the disease progression. In this article, a fully automatic approach for the segmentation of the carotid artery boundary in Proton Density Weighted Magnetic Resonance Images is presented. The approach relies on the expansion of the lumen contour based on a distance map built using the gray-weighted distance relative to the center of the identified lumen region in the image under analysis. Then, a Snake model with a modified weighted external energy based on the combination of a balloon force along with a Gradient Vector Flow-based external energy is applied to the expanded contour towards the correct boundary of the carotid artery. The average values of the Dice coefficient, Polyline distance, mean contour distance and centroid distance found in the segmentation of 139 carotid arteries were 0.83 ± 0.11, 2.70 ± 1.69 pixels, 2.79 ± 1.89 pixels and 3.44 ± 2.82 pixels, respectively. The segmentation results of the proposed approach were also compared against the ones obtained by related approaches found in the literature, which confirmed the outstanding performance of the new approach. Additionally, the proposed weighted external energy for the Snake model was shown to be also robust to carotid arteries with large thickness and weak boundary image edges.

Prognostic yield of imaging before and after recanalization treatments in ischemic stroke.

OBJECTIVES: The scores to predict outcome in ischemic stroke were validated prior to the approval of modern revascularization treatments. We evaluated the accuracy of pre and post-treatment models in a recent recanalization therapy cohort and whether radiological and ultrasound findings could improve their accuracy. MATERIAL & METHODS: We included 375 anterior circulation ischemic stroke patients treated with intravenous thrombolysis or thrombectomy during 2017 and 2018. We collected demographic, clinical, and imaging data. We built pre and post-treatment logistic regression models to predict independence (modified Rankin Scale 0-2) at 3 months. The models included the Alberta Stroke Program Early CT Score (ASPECTS), infarct volume (ABC/2 method), and the Thrombolysis in Brain Ischemia (TIBI) ultrasonographic grade of recanalization. We compared areas under the receiver operating characteristic curve (AUC). RESULTS: Our preintervention model, combining neurological deficit severity, age, and admission glycemia, was not improved by the inclusion of ASPECTS (AUC 0.80 vs 0.79, P = .28). Early neurological recovery at 24-hour significantly increased prognostic performance (AUC = 0.85, P < .01), which did not change by adding final infarct volume or the persistence of arterial occlusion of the affected territory (AUC = 0.86 and 0.85, P > .05). CONCLUSIONS: Models that combine simple variables such as neurological deficit severity, age, and admission glycemia were the most useful for predicting functional outcome in ischemic stroke patients submitted to revascularization treatments. Pre and post-treatment imaging findings did not enhance prognostic accuracy when compared to the patient's clinical improvement.

Moyamoya Syndrome after Radiation Therapy: a Clinical Report.

Moyamoya syndrome (MMS) is a rare, chronic and progressive vasculopathy with a characteristic angiographic pattern and well-recognized predisposing conditions, such as cranial therapeutic radiation. We report the case of a 36-year-old Caucasian female with a history of craniopharyngioma treated with whole-brain radiotherapy 20 years previously. She was admitted to the emergency department with disorientation and imperceptible speech lasting for 1 hour. Upon examination, she had slight motor aphasia, without sensory or motor deficits. However, the neurological deficits worsened on standing position. The computed tomography (CT) angiogram and transcranial Doppler ultrasonography revealed occlusion of the distal portion of the left internal carotid artery (ICA). Mechanical thrombectomy was attempted without success. Head CT was repeated, revealing left periventricular acute ischaemic stroke. The cerebral angiography showed total occlusion of the left ICA with an exuberant network of transdural collateral vessels, confirming MMS. The patient completed a functional rehabilitation program with progressive improvement of deficits and maintained a multidisciplinary follow-up. MMS is a serious late complication from cranial radiation therapy and a well-described risk factor for ischaemic stroke in younger patients. Therefore, early detection and prompt treatment are mandatory, as the consequences can be disastrous, such as cognitive and neurologic decline due to repeated strokes. LEARNING POINTS: Moyamoya syndrome should be considered in younger patients presenting with acute neurologic deficits, particularly those treated with cranial radiotherapy.The treatment of acute stroke in patients with moyamoya syndrome should include intravenous hydration and avoidance of hypotension.The benefit of antiplatelet agents is limited and equivocal for patients with moyamoya syndrome and oral anticoagulants are not recommended for long-term treatment.

Parachordal fistula--a case report and a short review.

Arteriovenous shunts of the neck and facial region rarely involve the external carotid artery and its branches. Most cases are considered to be iatrogenic or related to trauma but congenital shunts are rare. Parachordal arteriovenous fistulae are a group of embryologically derived arteriovenous shunts caused by defects involving the notochord, giving rise to cranial and paraspinal shunts. In the cranial regions, these shunts involve exclusively the metameric arteries--maxillary, ascending pharyngeal, occipital and vertebral. Signs and symptoms are variable, depending on the feeding vessel but also on the characteristics of the draining pathway. We report the case of a 17-year-old male patient with a shunt between the right internal maxillary artery and right external jugular vein detected at the age of 6, not associated with trauma, which we decided to treat because of an enlargement of the right cardiac atrium detected on routine examination. Digital subtraction angiography was performed to characterize the shunt followed by partial embolization with ballooning, coiling and Onyx injection. Echographic control 6 months after the procedure was compatible with complete occlusion of the shunt. We also perform a short review on this extremely rare entity.

Clinical characteristics and preferential location of intracranial mirror aneurysms: a comparison with non-mirror multiple and single aneurysms.

INTRODUCTION: The purpose of our study was to compare the clinical characteristics and preferential localization of aneurysms in three patient groups: single aneurysm, non-mirror multiple aneurysms, and mirror aneurysms. METHODS: We retrospectively reviewed the clinical and radiological data of 2223 consecutive patients harboring 3068 aneurysms registered at the Toronto Western Hospital between May 1994 and November 2010. The patients were divided into single, non-mirror multiple, or mirror aneurysm groups. Expected incidences of mirror aneurysms at each location were calculated on the basis of the single aneurysm incidences at each location. RESULTS: Patients with mirror aneurysms (n = 197) did not differ from patients with non-mirror multiple aneurysms (n = 392) in having female predominance (81.7 vs. 76.3 %) or a family history of intracranial aneurysm (20.5 vs. 17.6 %). When compared with expected incidences at each location, mirror aneurysms were more frequently found at the cavernous internal carotid artery (30 vs. 11.5 %) (p < 0.0001). Mirror aneurysms involving the posterior circulation were less frequent (6.7 %) than aneurysms in the single (19.6 %) or non-mirror multiple aneurysm groups (18.9 %) (p < 0.05). CONCLUSION: Patients with mirror aneurysms had similar clinical characteristics to non-mirror multiple aneurysm patients. Mirror aneurysms showed a predilection for the cavernous carotid artery, whereas they were comparatively rare in the posterior circulation.

[Bilateral hyperintensity of the pulvinar and dorsomedial nucleus of the thalamus in sporadic Creutzfeldt-Jakob disease]. / Hiperintensidade bilateral do pulvinar e núcleo dorso-medial do tálamo na forma esporádica da doença de Creutzfeldt-Jakob.

INTRODUCTION: Creutzfedt-Jakob Disease (CJD) is a rapidly progressive neurodegenerative disease caused by prions. Early diagnosis and the determination of its form are epidemiologically important, with strong impact on public health. Bilateral pulvinar hyperintensity, either alone (pulvinar sign) or in association with the dorsomedial nucleus of the thalamus (double hockey stick sign) on T2, FLAIR and diffusion weighted imaging (DWI), is a criterion for the probable diagnosis of the variant CJD (vCJD). Bilateral hyperintensity of the caudate, putamina and cortex is the usual pattern found in the sporadic CJD (sCJD). OBJECTIVE: Analysis of the imaging aspects on a sCJD patient showing T2 hyperintensity of the pulvinar and dorsomedial thalamic nucleus, in order to assess the magnetic resonance imaging (MRI) accuracy in the discrimination between vCJD and sCJD, when this lesion pattern is present. METHODS: We performed a MRI on a 62-year-old female with definitive diagnosis of sCJD made by anatomopathologic study of the brain tissue. Qualitative analysis of MRI, including DWI, T2 and FLAIR sequences, as well as lesional patterns found. RESULTS: Brain MRI showed hyperintensity of the caudate, putamina, pulvinar and dorsomedial nucleus of the thalamus, in DWI, T2 and FLAIR sequences; hypersignal of the caudate and putamina was greater than the signal intensity of the thalami. Hyperintensity of the hippocampus and frontal, temporal and parietal cortex were more obvious in FLAIR and DWI. COMMENT: Hyperintensity of the pulvinar and dorsomedial nucleus of the thalamus on sCJD may complicate the differential diagnosis with vCJD. True pulvinar sign and double hockey stick sign, consistent with vCJD, must only be considered if the hyperintensity is greater than signal intensity of the caudate and putamina.

[Conventional and diffusion-weighted magnetic resonance imaging and proton spectroscopy in MELAS]. / Ressonância magnética convencional, difusão e espectroscopia protónica na síndrome de MELAS.

INTRODUCTION: MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) is a mitochondrial hereditary dysfunction in which the physiopathological mechanism of cerebral lesions is not totally understood as yet. Typically, these lesions are described as having normal to increased apparent diffusion coefficient (ADC), and this has been used to distinguish stroke-like lesions from ischemic lesions. Notwithstanding this, within the last few years, there have been reports of diffusion restriction in stroke-like episodes. OBJECTIVES: Analysis of the diffusion characteristics on serial magnetic resonance imaging (MRI) over a 16 month period, on a patient with MELAS and stroke-like lesions, to investigate the controversial changes of the ADC, reported in the last years. Evaluation of the proton spectroscopy changes in stroke-like lesions and apparently spared brain. METHODS: We performed four serial magnetic resonance imaging (MRI), including two stroke-like episodes, in a 28-year-old man with MELAS (mitochondrial DNA mutation A3243G). Qualitative analysis of the magnetic resonance images, including the single voxel spectroscopy and ADC maps, with analysis of evolution patterns of the last ones. RESULTS: Both MRI that were performed during those episodes of stroke-like lesion revealed areas of diffusion restriction, coexisting areas of high ADC. During the chronic phase, there was a regression of those changes. Proton spectroscopy showed the presence of lactate and reduction of N-acetyl aspartate peak in stroke-like lesion and the presence of lactate in apparently spared brain. CONCLUSIONS: All alterations that were recorded strengthen the view that cytotoxic oedema can occur in stroke-like lesions. Thus, their presence should not weaken the possibility of MELAS, especially if those lesions affect the temporal, parietal and/or occipital lobes, or if they predominantly involve the cortical gray matter, spanning vascular borders and if proton spectroscopy reveals lactate peak in the apparently spared brain.

[Cerebral venous thrombosis: retrospective analysis of 49 cases]. / Trombose venosa cerebral: análise retrospectiva de 49 casos.

INTRODUCTION: Cerebral Venous Thrombosis (CVT) is a rare and potentially life-threatening disease, accounting for about 0.5% of stroke cases. However, it is believed to be an underdiagnosed condition. Early diagnosis requires a high degree of suspicion and appropriate use of imaging modalities. OBJECTIVES: Imagiological and clinical characterization of CVT cases diagnosed at our hospital from 2004 to 2007. METHODS: This study was a retrospective, cross-sectional analysis from 2004 to 2007, using our institution database. We reviewed hospital discharge data to assess the incidence of CVT. The study population consisted of 49 patients. Retrospective review of the clinical data and imaging studies of these patients was then performed. RESULTS: Of the 49 patients with confirmed CVT, 38 were female. Patient age varied between 16 and 75 years, with an average of 42.6 years. Thrombotic risk factors were found in 43 patients; the most frequent was dyslipidemia (n = 22) followed by oral contraceptive use (n = 18). Initial head Computerized Tomography (CT) was normal in six cases. Diagnosis was made by Magnetic Resonance (MR) in 38 cases, Cerebral CT-Venography in 10 cases and Digital Subtraction Angiography in one case. Average time from onset of symptoms to diagnosis was nine days; this was not significantly different when comparing the group diagnosed by MR with the group diagnosed by CT-Venography. Right transverse sinus was the most frequent location of thrombosis (n = 36). Only in four cases thrombosis did not involve the lateral sinuses. CONCLUSIONS: Lateral sinus thrombosis is a frequent variety of CVT, accounting for 91.8% of our cases. A negative Head CT scan does not exclude the presence of cerebral venous thrombosis; therefore appropriate imaging study should be performed whenever there's a high degree of clinical suspicion. Cerebral CT-Venography seems to be a good alternative to MR for the diagnosis of CVT.