OBJECTIVE: To establish reference intervals for the fetal cisterna magna volume by means of two-dimensional (2D) method using the multiplanar mode of three-dimensional ultrasonography. MATERIALS AND METHODS: Cross-sectional study with 224 healthy pregnant women between the 17th and 29th gestational weeks. The volume was automatically obtained by multiplying the three major axes in axial and sagittal planes by the constant 0.52. Polynomial regression was utilized to establish the correlation between fetal cisterna magna volume and gestational age, with adjustments by coefficient of determination (R²). Reliability and agreement were obtained by intraclass correlation coefficient (ICC) and limits of agreement, respectively. RESULTS: Mean fetal cisterna volume with the 2D method ranged from 0.71 ± 0.19 cm³ to 4.18 ± 0.75 cm³ at the 17th and 29th weeks, respectively. The authors observed a good correlation between fetal cisterna magna volume and gestational age (R² = 0.67), excellent intraobserver reliability and agreement with ICC = 0.89 and limits of agreement 95% (–52.0; 51.8), respectively, and low interobserver reliability and agreement with ICC = 0.64 and limits of agreement 95% (–110.1; 84.6), respectively. CONCLUSION: Reference intervals for fetal cisterna magna volume by means of 2D method using the multiplanar mode of three-dimensional ultrasonography were established and presented excellent intraobserver reliability and agreement.

Keywords: Fetus; Cisterna magna; Reference intervals; Two-dimensional ultrasonography; Three-dimensional ultrasonography.

OBJECTIVE: To assess the accuracy in the prediction of both early and late preeclampsia by flow-mediated dilation of the brachial artery (FMD), a biophysical marker for endothelial dysfunction. MATERIALS AND METHODS: A total of 91 patients, considered at high risk for development of preeclampsia were submitted to brachial artery FMD between 24 and 28 weeks of gestation. RESULTS: Nineteen out of the selected patients developed preeclampsia, 8 in its early form and 11 in the late form. With a cut-off value of 6.5%, the FMD sensitivity for early preeclampsia prediction was 75.0%, with specificity of 73.3%, positive predictive value (PPV) of 32.4% and negative predictive value (NPV) of 91.9%. For the prediction of late preeclampsia, sensitivity = 83.3%, specificity = 73.2%, PPV = 34.4% and NPV = 96.2% were observed. And for the prediction of all associated forms of preeclampsia, sensitivity = 84.2%, specificity = 73.6%, PPV = 45.7% and NPV = 94.6% were observed. CONCLUSION: FMD of the brachial artery is a test with good accuracy in the prediction of both early and late preeclampsia, which may represent a positive impact on the follow-up of pregnant women at high risk for developing this syndrome.

Keywords: Preeclampsia; Ultrasonography; Vascular endothelium; Prediction.

OBJECTIVE: To assess the non-radiologist physicians' knowledge on the use of ionizing radiation in imaging. MATERIALS AND METHODS: Cross-sectional study utilizing an anonymous questionnaire responded by physicians in clinical and surgical specialties, divided into two parts as follows: one including questions about the physicians' characteristics, frequency of imaging studies requests and participation in professional updating events, and another part including multiple choice questions approaching general knowledge about radiation, optimization principles and radioprotection. RESULTS: From a total of 309 questionnaires, 120 (38.8%) were responded, 50% by physicians in surgical specialties and 50% in clinical specialties; respectively 45% and 2.5% of physicians responded that magnetic resonance imaging and ultrasonography use ionizing radiation. Overall, the average grade was higher for surgical specialists with no significant difference, except for the question about exposure in pregnant women (p = 0.047). Physicians who are professionally updated, particularly those attending clinical meetings (p = 0.050) and participating in teaching activities (p = 0.047), showed statistically superior knowledge about ionizing radiation as compared with others. CONCLUSION: The non-radiologist physicians' knowledge is heterogeneous and in some points needs to be improved. Multidisciplinary clinical meetings and teaching activities are important ways to disseminate information on the subject.

Keywords: Ionizing radiation; Knowledge; Physicians; Imaging diagnosis; Radiation protection; Questionnaire.

OBJECTIVE: To develop a study aiming at optimizing myocardial perfusion imaging. MATERIALS AND METHODS: Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The ^99mTc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. RESULTS: The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. CONCLUSION: The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol.

Keywords: Myocardial perfusion imaging; Optimization; Anthropomorphic phantom.

OBJECTIVE: Several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding. MATERIALS AND METHODS: The percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images. RESULTS: The authors observed a reduction in entrance dose by 30% and in CTDI_vol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding. CONCLUSION: As expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding.

Keywords: Computed tomography; Shielding; Bismuth; Dose reduction; Lead.

With the steep increase in the use of cross-sectional imaging in recent years, the incidentally detected adrenal lesion, or "incidentaloma", has become an increasingly common diagnostic problem for the radiologist, and a need for an approach to classifying these lesions as benign, malignant or indeterminate with imaging has spurred an explosion of research. While most incidentalomas represent benign disease, typically an adenoma, the possibility of malignant involvement of the adrenal gland necessitates a reliance on imaging to inform management decisions. In this article, we review the literature on adrenal gland imaging, with particular emphasis on computed tomography, magnetic resonance imaging, and photon-emission tomography, and discuss how these findings relate to clinical practice. Emerging technologies, such as contrast-enhanced ultrasonography, dual-energy computed tomography, and magnetic resonance spectroscopic imaging will also be briefly addressed.

Keywords: Adrenal gland; Adenoma; Cancer; Diagnosis; Radiology.

Axillary staging of patients with early-stage breast cancer is essential in the treatment planning. Currently such staging is intraoperatively performed, but there is a tendency to seek a preoperative and less invasive technique to detect lymph node metastasis. Ultrasonography is widely utilized for this purpose, many times in association with fine-needle aspiration biopsy or core needle biopsy. However, the sonographic criteria for determining malignancy in axillary lymph nodes do not present significant predictive values, producing discrepant results in studies evaluating the sensitivity and specificity of this method. The present study was aimed at reviewing the literature approaching the utilization of ultrasonography in the axillary staging as well as the main morphological features of metastatic lymph nodes.

Keywords: Breast cancer; Axillary lymph nodes; Axillary ultrasonography; Morphological features.

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.

Arteriovenous fistulae of the cavernous sinus are rare and difficult to diagnose. They are classified into dural cavernous sinus fistulae or direct carotid-cavernous fistulae. Despite the similarity of symptoms between both types, a precise diagnosis is essential since the treatment is specific for each type of fistula. Imaging findings are remarkably similar in both dural cavernous sinus fistulae and carotid-cavernous fistulae, but it is possible to differentiate one type from the other. Amongst the available imaging methods (Doppler ultrasonography, computed tomography, magnetic resonance imaging and digital subtraction angiography), angiography is considered the gold standard for the diagnosis and classification of cavernous sinus arteriovenous fistulae. The present essay is aimed at didactically presenting the classification and imaging findings of cavernous sinus arteriovenous fistulae.

Keywords: Arteriovenous fistula; Cavernous sinus; Ultrasonography; Computed tomography; Magnetic resonance imaging; Angiography.

Lymphocytic mastopathy affects both young and middle-aged women and is frequently associated with autoimmune diseases. Diagnosis is done by associating clinical (breast tissue thickening or hardened breast lump), radiological (increased breast density, presence of mass and calcifications), sonographic (nodule with posterior acoustic shadowing), histopathological (fibrosis and lymphocytic infiltrate) and immunohistochemical findings. Lymphocytic mastopathy is a benign entity that may mimic carcinoma. The authors report the case of a patient with lymphocytic mastopathy.

Keywords: Lymphocytic mastopathy; Breast cancer; Benign breast tumors.

Churg-Strauss syndrome is a rare systemic disease primarily characterized by hypereosinophilia, asthma and vasculitis. The lung is the organ most frequently involved. In the present report, the authors describe a relatively rare finding in this disease – the presence of a pulmonary nodule –, while recalling the main radiological findings and the most relevant differential diagnoses.

Keywords: Vasculitis; Eosinophilia; Asthma.

Sclerosing encapsulating peritonitis is a rare and frequently severe entity characterized by total or partial involvement of small bowel loops by a membrane of fibrous tissue. The disease presents with nonspecific clinical features of intestinal obstruction, requiring precise imaging diagnosis to guide the treatment. The present report emphasizes the importance of computed tomography in the diagnosis of this condition and its confirmation by surgical correlation.

Keywords: Peritonitis; Peritoneal fibrosis; Sclerosing encapsulating peritonitis; Computed tomography.