Congenital Absence of the Internal Carotid Artery With Intercavernous Anastomosis.

Absence of the internal carotid artery (ICA) is a rare congenital anomaly. Six pathways of alternative collateral circulation have been described. We present a case depicting absence of the left ICA and a Lie type D pattern of collateral circulation, with an intercavernous branch from the right cavernous ICA passing along the floor of the sella to the contralateral side, supplying the left middle cerebral artery. Association with cerebral aneurysms has been found, as seen in this case. Recognition of this vascular anatomic variant is important to understand thromboembolic disease in these patients and the increased risks of surgery, such as transsphenoidal pituitary surgery. Also, it highlights the importance of imaging these patients to detect and monitor associated cerebral aneurysms.

[Double aortic arch: incidental cerebral angiography finding in an adult patient with headache--embrionary cardiovascular morphogenic pattern review]. / Duplo arco aórtico: achado acidental em angiografia cerebral de um paciente adulto com cefaleias--revisão do padrão de morfogénese embrionária cardiovascular a propósito de um caso clínico.

INTRODUCTION: Cerebral angiography is a technique used to detect cerebral vessel anomalies. It is critical that a neuroradiologist is familiar with the normal anatomic development and its anomalies as, during an angiography, they may influence the way the procedure is done. METHODS: Regarding an incidental finding of a double aortic arch during a cerebral angiography in an adult patient, the authors proceeded to a bibliographic review of the normal embriogenic cardiovascular morphogenesis patterns and its anomalies. DISCUSSION: The existence of a double aortic arch constitutes an embrionary pattern typical at six weeks of gestation that results from the process of progression/regression of the six pairs of pharyngeal arches; usually the double aortic arch regresses during the seventh week of gestation. When the fourth right pharyngeal arch and the right dorsal aorta do not regress, this double aortic pattern persists after birth. There are several symptoms related to this anomaly but in some rare cases, like the one presented, they might be absent and are only identified accidentally. CONCLUSION: Studying the pattern of cardiovascular morphogenesis and its anomalies helps the neuroradiologist performing a cerebral angiogram.

Rapidly progressive cognitive impairment, ataxia, and myoclonus: an unusual presentation of a dural arteriovenous fistula.

Dural arteriovenous fistulas (DAVFs) have a wide range of clinical presentations, including dementia associated with white matter changes (WMCs). We report a case of DAVF presenting as a rapid progressive dementia and myoclonus without WMCs. A 64-year-old hypertensive and diabetic man was admitted because of a 3-month history of progressive cognitive decline, extrapyramidal and cerebellar signs, and myoclonus. Magnetic resonance imaging (MRI) scans of the brain showed dilated cerebellar veins and T2WI hypersignal in the basal ganglia without WMCs. After admission, he suffered sequential bilateral deep intracerebral hemorrhages. A repeated angioMRI disclosed thrombosis of the distal sagittal and the proximal lateral sinuses. Angiography revealed a torcullar region DAVF. Embolization of the dural fistula was performed. On follow-up, the patients' cognitive deficits improved and myoclonus disappeared. The clinical picture may be explained by venous hypertension in the deep venous system, producing bilateral basal ganglia/thalamic dysfunction and in the posterior fossa. This case shows that DAVFs can produce subcortical dementia without involvement of the deep white matter.

[The contribution of perfusion CT in stroke]. / O contributo da tomografia computorizada de perfusão no acidente vascular cerebral.

Multisection computed tomography (MSCT) was introduced in 1998 and improved neuroimaging quality, in particular concerning acute stroke. Previously, non-enhanced CT was used not only to detect early stroke signs, but also to exclude hemorrhage and non-vascular pathology responsible for the acute neurological deficit. Nowadays, using Perfusion CT (PCT) it is possible to obtain a functional study of the cerebral hemodinamics after injection of a fast bolus of contrast. Multi-voxel analysis of the time-attenuation curves delivers colour maps of Cerebral Blood Flow (CBF), Mean Time Transit (MTT) and Cerebral Blood Flow (CBF). Based on specific patterns of hemodinamic changes it is possible to differentiate between irreversible and reversible brain damage--"tissue at risk", which is essential for choosing an appropriate therapy. The authors will discuss data acquisition, post-processing and image interpretation and analysis starting from two clinical examples.

Invasive aspergillosis of the central nervous system after allogeneic stem cell transplantation.

Central nervous system aspergillosis is a rare infectious complication in patients submitted to allogeneic stem cell transplantation. When it arises, this infection appears early post-transplant and most patients present with multiple central nervous system lesions. We report the clinical case of a 52 year old woman with IgGk multiple myeloma in relapse after a matched related allogeneic bone marrow transplant, who presented with a single large central nervous system Aspergillus lesion 11 months post-transplant in the setting of acute graft vs. host disease developing after the infusion of donor leucocytes. Although liposomal amphotericin B was promptly instituted, the patient died 1 week after the diagnosis.