OBJECTIVE: To determine a reference curve for the peak systolic velocity of fetal middle cerebral artery. MATERIALS AND METHODS: The authors developed a cross-sectional study with 143 healthy pregnant women between the 23rd and 35th gestational weeks. A bidimensional axial scan of the fetal skull was performed, including the thalami and pellucid septum. Subsequently, the middle cerebral artery was visualized with the color Doppler mode. The pulsed-wave Doppler transducer was positioned over the origin of this vessel, at < 20° insonation angle. The correlation between the peak systolic velocity of the middle cerebral artery and gestational age was evaluated by means of the Pearson's correlation coefficient (r). Regression models were utilized in the construction of a table with multiples of the medians of the middle cerebral artery peak systolic velocity for each gestational age. Additionally, reference values for this variable were determined. RESULTS: A strong correlation was observed between the middle cerebral artery peak systolic velocity and gestational age (r = 0.70; p < 0.001). Values of middle cerebral artery peak systolic velocity were calculated for the following multiples of the medians: 1.0, 1.29, 1.5, 1.55. The 2.5th and 97.5th percentiles were determined for the middle cerebral artery peak systolic velocity ranging between 24.33 cm²/s and 78.36 cm²/s. CONCLUSION: A nomogram for the fetal middle cerebral artery peak systolic velocity during the second half of pregnancy was generated.

Keywords: Middle cerebral artery, Doppler, Ultrasonography, Nomogram, Fetus

OBJECTIVE: To evaluate and compare existing ultrasound findings in women with Rh-alloimmunized pregnancies with diagnosis of fetal anemia by spectrophotometric analysis of amniotic fluid or Doppler ultrasound of the fetal middle cerebral artery. MATERIALS AND METHODS: This was an observational descriptive study involving 99 patients evaluated between January 1995 and January 2004. Patients were divided into two groups: 74 Rh-isoimmunized women submitted to spectrophotometry of the amniotic fluid (group S) and 25 Rh-isoimmunized women submitted to Doppler ultrasound of fetal middle cerebral artery (group D) to evaluate fetal anemia. Ultrasound findings in the two groups were compared. RESULTS: Placental anomalies, mainly placentomegaly and textural irregularities were more frequently seen in pregnant women followed up with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound (64% X 32%, p = 6,294). CONCLUSION: The frequency of abnormal ultrasound findings was 2-fold higher in pregnancies evaluated with spectrophotometry of the amniotic fluid compared to those followed up with Doppler ultrasound.

Keywords: Red blood cell isoimmunization, Fetal anemia, Middle cerebral artery, Doppler ultrasonography, Isoantibodies, Fetal erythroblastosis

Intracranial aneurysm rupture is a rare cause of morbidity and mortality in pregnancy, with a few endovascular treatment cases reported in the literature. In this study we report a case of a 37-year-old woman in the eighth gestational month presenting tomographic findings and clinical manifestations compatible with subarachnoid hemorrhage (Hunt Hess III) due to rupture of an ophthalmic segment aneurysm in the internal carotid artery.

Keywords: Cerebral aneurysm, Subarachnoid hemorrhage, Pregnancy, Endovascular embolization

OBJECTIVE: To determine the frequency and localization of parenchymal abnormalities in cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography as well as their correlation with the territory and affected venous drainage. MATERIALS AND METHODS: Retrospective analysis (1996 to 2004) of 21 patients (3 male and 18 female) age range between 3 and 82 years (mean 40 years, median 36 years) with clinical and radiological diagnosis of cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography in 2D PC, 3D PC and contrast-enhanced 3D TOF sequences. The statistical analysis was performed with the qui-square test. Four patients had follow-up exams and three patients underwent digital subtraction angiography. RESULTS: Main predisposing factors were: infection, use of oral contraceptives, hormone replacement therapy and collagenosis. Predominant symptoms included: focal deficit, headache, alteration of consciousness level and seizures. Most frequent parenchymal manifestations were: cortical/subcortical edema or infarct, venous congestion and collateral circulation, meningeal enhancement and thalamic and basal ganglia edema or infarct. Occlusion occurred mainly in superior sagittal, left transverse, left sigmoid and straight sinuses. Cavernous sinus and cortical veins thrombosis are uncommon events. CONCLUSION: Cerebral venous thrombosis is an uncommon cause of stroke, with favorable prognosis because of its reversibility. Diagnosis is highly dependent on the radiologist capacity to recognize the presentations of this disease, principally in cases where the diagnosis is suggested by parenchymal abnormalities rather than necessarily by visualization of the thrombus itself. An accurate and rapid diagnosis allows an immediate treatment, reducing the morbidity and mortality rates.

Keywords: Magnetic resonance, Cerebral venous thrombosis, Cerebral infarct, Intracranial hemorrhage

We conducted a study to assess and compare the findings of computed tomography angiography and digital subtraction angiography in patients with intracranial aneurysms, and to evaluate the possibility of a larger utilization of computed tomography angiography in Brazil. Eight patients were studied, 7 with nontreated and 1 with a treated aneurysm. The results were compared with those from the medical literature. Tests were performed at a private clinic and in two private hospitals in Rio de Janeiro, RJ, Brazil. There was good correlation between the two investigational methods regarding diagnosis, follow-up and pretreatment evaluation of these lesions. Computed tomography angiography showed to be less invasive, less costly and more accessible. We concluded that computed tomography angiography should be used more often in the evaluation of intracranial aneurysms.

Keywords: Intracranial aneurysm, X-ray computed tomography, Cerebral angiography, Radiology

OBJECTIVE: To report results of the application of endovascular techniques in the management of scalp cirsoid aneurysms. MATERIALS AND METHODS: Four patients diagnosed with cirsoid aneurysms were submitted to treatment by endovascular approach. All the four patients included in the present series had arteriovenous malformations and were treated solely by embolization. RESULTS: Three of the patients underwent endovascular treatment by transarterial embolization and one was treated by direct puncture of the venous segment. Both clinical and cosmetic outcomes were satisfactory in all of the patients. Clinical relapse was not observed along the follow-up period. CONCLUSION: The endovascular approach is safe and effective in the management of crisoid aneurysms. Although this technique can be used as an adjuvant or complement to surgery, particularly in cases where deep afferents are involved, complete resolution can be achieved only with endovascular treatment. The choice of treatment method should be based on a range of typical characteristics of the lesion, including angioarchitecture, size and clinical presentation.

Keywords: Arteriovenous fistula; Cirsoid aneurysm; Cerebral angiography; Embolization.

Objective: Study of the cerebral ventricular system by ultrasonography with the objective of establishing parameters for the diagnosis of mild ventricular dilatation. Materials and Methods: Prospective study of 105 healthy, full term infants aged 1–6 months, submitted to monthly scans for morphological data evaluation and measurements of ventricle/hemisphere ratio, and anteroposterior diameter of frontal horn and fourth ventricle. Results: Normality mean, standard deviation and percentile were obtained for each age range. Negative results were observed in the search for anechoic halo surrounding the posterior two thirds of the choroid plexus on coronal section VI for evaluation of temporal/posterior horns, and the third ventricle was seen as an anechoic cleft < 1 mm on coronal section V in all of the evaluated infants. Conclusion: Sonographic findings related to temporal/posterior horns and third ventricle associated with the 95th percentile as upper limit of normality can be utilized as parameters for a simplified diagnosis of mild ventricular dilatation.

Keywords: Cerebral ventricles; Transfontanelle ultrasonography; Brain ultrasonography; Pediatric sonographic measurements.

OBJECTIVE: To investigate whether breastfeeding influence the cerebral blood-flow velocity. MATERIALS AND METHODS: The present study included 256 healthy term neonates, all of them with appropriate weight for gestational age, 50.8% being female. Pulsatility index, resistance index and mean velocity were measured during breastfeeding or resting in the anterior cerebral artery, in the left middle cerebral artery, and in the right middle cerebral artery of the neonates between their first 10 and 48 hours of life. The data were analyzed by means of a paired t-test, Brieger's f-test for analysis of variance and linear regression, with p < 0.01 being accepted as statistically significant. RESULTS: Mean resistance index decreased as the mean velocity increased significantly during breastfeeding. Pulsatility index values decreased as much as the resistance index, but in the right middle cerebral artery it was not statistically significant. CONCLUSION: Breastfeeding influences the cerebral blood flow velocities.

Keywords: Cerebral blood flow; Breastfeeding; Doppler ultrasonography; Neonates.

Neurocysticercosis is a disease characterized by the involvement of the central nervous system by the intermediate larval stage of the parasite Taenia solium. The larva degeneration process and the inflammatory reaction of the body cause clinical symptoms. The authors report a case of clinical and radiological reactivation of nodular calcified neurocysticercosis in a patient who was asymptomatic for more than 20 years. Antiparasitic treatment showed a good response.

Keywords: Neurocysticercosis; Reactivation; Cerebral calcifications.

OBJECTIVE: The present study was aimed at estimating the doses received by physicians and patients during cerebral angiography procedures in a public hospital of Recife, PE, Brazil. MATERIALS AND METHODS: The study sample included 158 adult patients, and during the procedures the following parameters were evaluated: exposure parameters (kV, mAs), number of acquired images, reference air kerma value (K_a,r) and air kerma-area product (P_KA). Additionally, the physicians involved in the procedures were evaluated as for absorbed dose in the eyes, thyroid, chest, hands and feet. RESULTS: The results demonstrated that the doses to the patients' eyes region were relatively close to the threshold for cataract occurrence. As regards the physicians, the average effective dose was 2.6 µSv, and the highest effective dose recorded was 16 µSv. CONCLUSION: Depending on the number of procedures, the doses received by the physicians may exceed the annual dose limit for the crystalline lenses (20 mSv) established by national and international standards. It is important to note that the high doses received by the physicians are due to the lack of radiation protection equipment and accessories, such as leaded curtains, screens and protective goggles.

Keywords: Dosimetry; Interventional radiology; Cerebral angiography.

The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (ependymoma, pilocytic astrocytoma, central neurocytoma, ganglioglioma, choroid plexus papilloma, primitive neuroectodermal tumors, meningioma, epidermoid tumor). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some image patterns that may facilitate the differential diagnosis.

Keywords: Neoplasms; Cerebral ventricle neoplasms; Central nervous system; Magnetic resonance imaging.

The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (colloid cyst, oligodendroglioma, astroblastoma, lipoma, cavernoma) and of inflammatory/infectious lesions (neurocysticercosis and an atypical presentation of neurohistoplasmosis). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some imaging patterns that may facilitate the differential diagnosis.

Keywords: Neoplasms; Cerebral ventricle neoplasms; Central nervous system; Magnetic resonance imaging.

Os nervos cranianos representam extensões das estruturas funcionais do cérebro que cruzam a cabeça e o pescoço. Eles estão ligados a diferentes estruturas cranianas e se relacionam com diversas doenças. Uma compreensão profunda de sua complexa anatomia e aparência normal de imagem permite ao examinador identificar e caracterizar com mais precisão as anormalidades. A ressonância magnética com contraste é uma importante ferramenta para avaliar essas estruturas, especialmente as sequências tridimensionais de precessão livre de estado estacionário, que proporcionam alta resolução espacial e de partes moles, apesar da fina espessura dos nervos cranianos. Na maioria dos casos, os achados de imagem são inespecíficos, e uma anamnese completa, exame físico dirigido e testes laboratoriais são necessários para estreitar o diagnóstico diferencial. Este ensaio iconográfico ilustra e discute doenças congênitas, traumáticas e vasculares dos nervos cranianos, mostrando imagens em uma abordagem fisiopatológica.

Keywords: Neuroimagem/métodos; Radiologia/métodos; Ressonância magnética/métodos; Nervos cranianos/diagnóstico por imagem.

Moyamoya disease is a chronic occlusive cerebrovascular disease that is non-inflammatory and non-atherosclerotic. It is characterized by endothelial hyperplasia and fibrosis of the intracranial portion of the carotid artery and its proximal branches, leading to progressive stenosis and occlusion, often clinically manifesting as ischemic or hemorrhagic stroke with high rates of morbidity and mortality. On cerebral angiography, the formation of collateral vessels has the appearance of a puff of smoke (moyamoya in Japanese), which became more conspicuous with the refinement of modern imaging techniques. When there is associated disease, it is known as moyamoya syndrome. Treatments are currently limited, although surgical revascularization may prevent ischemic events and preserve quality of life. In this review, we summarize recent advances in moyamoya disease, covering aspects of epidemiology, etiology, presentation, imaging, and treatment strategies.

Keywords: Moyamoya disease; Cerebrovascular disorders; Intracranial arterial diseases; Cerebral arterial diseases; Cerebral revascularization.

OBJECTIVE: To evaluate cerebrospinal fluid dynamics, using cine phase-contrast magnetic resonance imaging (cine-PC MRI), in healthy pediatric subjects, determining the normal flow values in this population, as well as identifying differences related to age, sex, and body surface area. MATERIALS AND METHODS: This was a descriptive cross-sectional study involving 32 healthy children and adolescents, in whom the flow of cerebrospinal fluid through the cerebral aqueduct was evaluated quantitatively with cine-PC MRI. We used specialized software to analyze the images obtained with cine-PC MRI, drawing a region of interest on the aqueduct. A flow-time curve was obtained, as were automated measurements of the various parameters. RESULTS: The following normal (mean) values were obtained: net flow, 1.10 ± 0.99 mL/m; stroke volume, 12.2 ± 10.1 μL/cycle; mean velocity, 0.72 ± 1.00 cm/s; peak systolic velocity, 5.28 ± 2.30 cm/s; peak diastolic velocity, 4.51 ± 1.77 cm/s. These values were not affected by age or sex. In addition, body surface area was not found to correlate significantly with mean velocity or stroke volume. CONCLUSION: In children and adolescents, the basic cerebrospinal fluid flow parameters, as determined by cine-PC MRI, appear to be independent of age and sex.

Keywords: Cerebrospinal fluid; Magnetic resonance imaging, cine; Cerebral aqueduct; Hydrodynamics.