OBJECTIVE: To describe changes of the biliary tree demonstrated by magnetic resonance cholangiography (MRC) in patients with the hepatosplenic presentation of schistosomiasis mansoni, and evaluating the interobserver agreement in the detection of schistosomal cholangiopathy. MATERIALS AND METHODS: Prospective, cross-sectional study involving 24 patients with hepatosplenic schistosomiasis and 6 healthy patients (control group) submitted to biliary tree evaluation by MRC. The following changes of the biliary tree were considered: distortion, thinning, stenosis, dilation and irregularity. The interobserver agreement in the detection of biliary tree changes was calculated with the McNemar's test and the kappa index of agreement (κ). RESULTS: The interobserver agreement in the detection of distortion and thinning of the biliary tree was almost perfect (κ = 0.867; confidence interval [CI] 95% [0.512-1.0] and κ = 0.865; CI 95% [0.51-1.0], respectively). There was a substantial agreement for stenosis (κ = 0.78; CI 95% [0.424-1.0]), moderate agreement for dilation (κ = 0.595; CI 95% [0.247-0.942]) and mild agreement for thinning (κ = 0.229; CI 95% [0.095-0.552]). CONCLUSION: In a decreasing order of frequency, the changes of the biliary tree were observed: distortion, thinning, stenosis, dilation and irregularity. The interobserver agreement for signs of schistosomal cholangiopathy was almost perfect for distortion and thinning, and substantial for stenosis.

Keywords: Schistosomiasis mansoni, Magnetic resonance imaging, Cholangiography, Biliary ducts

OBJECTIVE: To study the utility of diffusion-weighted magnetic resonance imaging in the differentiation between benign and malignant breast lesions. MATERIALS AND METHODS: Forty-five women (mean age, 46.1 years) with 52 focal breast lesions underwent diffusionweighted magnetic resonance imaging. The calculation of apparent diffusion coefficient (ADC) was based on the ADC map reflecting five b values (0, 250, 500, 750, and 1000 s/mm²). The mean ADC value of each lesion was correlated with imaging findings and histopathologic results. Cutoff ADC, sensitivity and specificity of diffusion-weighted imaging in the differentiation between benign and malignant lesions were calculated. P < 0.05 was considered as statistically significant. RESULTS: The mean ADC was significantly lower for malignant lesions (0.92 ± 0.26 × 10-3 mm²/s) as compared with benign lesions (1.50 ± 0.34 × 10-3 mm²/s) (P < 0.0001). Diffusion-weighted imaging showed high sensitivity and specificity (both, 92.3%) in the differentiation between benign and malignant lesions. CONCLUSION: Diffusion-weighted imaging is a potential resource as an adjuvant to breast magnetic resonance imaging to differentiate benign from malignant lesions. Such sequence can be easily added to the standard breast magnetic resonance imaging protocol, without implying any significant increase in examination time.

Keywords: Breast cancer, Diffusion-weighted imaging, Magnetic resonance imaging

OBJECTIVE: To evaluate the efficacy of free-breathing magnetic resonance sequence with three excitations in the determination of ventricular volumes and masses in individuals without breathholding. MATERIALS AND METHODS: Left ventricular volumes and masses determined in 32 healthy volunteers through two cine magnetic resonance imaging sequences were compared: the first sequence, traditionally utilized and considered as a standard, performed under apnea, with a single excitation, and the second one, with free-breathing and three excitations. Three observers at different levels of experience evaluated the agreement and reproducibility. Intraclass correlation coefficient, paired t-test, Bland-Altman plots and sign test were utilized for statistical analysis. RESULTS: According to the two most experienced observers, intraclass correlation coefficients were > 0.913, the paired t-test demonstrated P values > 0.05, Bland-Altman plots had differences randomly distributed around zero and the sign test descriptive levels were > 0.05. CONCLUSION: The sequence evaluated presents an excellent agreement and reproducibility as compared with the standard sequence, and can be utilized in patients with respiratory limitations.

Keywords: Heart, Ventricular function, Magnetic resonance imaging

OBJECTIVE: To measure the uterine cervical length by using transvaginal ultrasonography in patients with clinical signs compatible with preterm labor threat, and correlating each individual measurement with spontaneous pregnancy interruption within seven days. MATERIALS AND METHODS: Sonographic examinations were performed in 72 patients with clinical signs compatible with preterm labor threat. RESULTS: Sensitivity was 90.5%, specificity, 98%, positive predictive value, 95%, and negative predictive value, 96%. A standard uterine cervix length of 15 mm was considered as a predictive value for preterm labor. CONCLUSION: It seems to be possible to foresee preterm delivery in patients whose cervical length is < 15 mm. Such observation could contribute to a timely corticosteroid administration to accelerate fetal lung maturity.

Keywords: Transvaginal ultrasonography, Preterm labor, Uterine cervical length, Preterm labor diagnosis

OBJECTIVE: To evaluate three cases of cervical lymphangioma with magnetic resonance imaging and correlating with sonographic findings. MATERIALS AND METHODS: Three pregnant women between the 24th and 35th gestational weeks, with sonographic findings suggestive of fetal cystic hygroma, were submitted to magnetic resonance and subsequently to a new ultrasonography for correlation of imaging findings. Tumors size, location, content and extent were evaluated both at magnetic resonance imaging and ultrasonography. RESULTS: Findings regarding tumor location, size and content were similar for both methods. All the lesions were found in the posterior and lateral cervical space. As regards the tumors content, two of the lesions were predominantly cystic, with thin septations, and the other was heterogeneous. Lesions extent and adjacent structures invasion were better characterized by magnetic resonance imaging, with appropriate demonstration of invasion of the pinna in one case and invasion of the superior mediastinum in another. CONCLUSION: Fetal magnetic resonance imaging can be a useful adjuvant to obstetric ultrasonography in cases of lymphangioma because of its higher accuracy in the determination of these tumors extent and adjacent structures invasion, allowing a better postnatal surgical planning.

Keywords: Fetus, Lymphangioma, Cystic hygroma, Ultrasonography, Fetal magnetic resonance imaging

OBJECTIVE: To compare and quantify irradiated lung volumes using two-dimensional (2D) and three-dimensional (3D) conformal planning for radiotherapy in the treatment of lung cancer. MATERIALS AND METHODS: 2D and 3D conformal radiotherapy plannings were performed for 27 patients with lung cancer. Prescribed doses ranged from 45 to 66 Gy. The analysis covered the doses to planning target volume (PTV), gross tumor volume (GTV) and lungs (lung volume receiving 20 Gy or 30 Gy - V20 and V30, respectively, and mean dose). The doses to adjacent organs at risk (spinal cord, esophagus and heart) were maintained below the tolerance limits. RESULTS: GTV ranged from 10.5 to 1,290.0 cm³ (mean, 189.65 cm³). On average, a total of 59.33 fields were utilized in the 2D planning and 75.65 fields in the 3D planning. Lung volumes were significantly preserved (P < 0.05) with the 3D conformal planning in all the evaluated cases, with about 15% decrease in the irradiated lung volumes. Lungs without tumor were most benefited from this technique. CONCLUSION: 3D radiotherapy allowed a better sparing of the lungs, both in cases of early and advanced tumors. 3D radiotherapy should be used in the treatment of patients with lung cancer, even in cases of large tumors.

Keywords: Lung cancer, Radiotherapy, Conformal radiotherapy, Organs at risk, Lung volumes

OBJECTIVE: The purpose of the present study was to investigate the influence of ionizing radiation from x-rays and gamma rays on the molecular structure stability of several radiologic contrast media employed in diagnostic imaging by means of ¹H and 13C nuclear magnetic resonance spectroscopy. MATERIALS AND METHODS: Eight different types of iodinated contrast media (three ionic and five non-ionic) were exposed to x-rays and gamma rays irradiation. Subsequently, the ¹H and 13C{¹H} nuclear magnetic resonance spectra of these contrast media were collected. RESULTS: The ¹H and 13C{¹H} nuclear magnetic resonance spectra of both ionic and non-ionic contrast media irradiated by x-rays or gamma rays demonstrated the absence of any alteration of the contrast media chemical composition. CONCLUSION: There is no problem in keeping contrast media inside examination rooms or close to radiological equipment. It is important to mention that, during the tests, the samples were directly irradiated, while in a radiology examination room, the irradiation is not direct and, therefore, radiation levels in these cases are much lower than those employed in the present study.

Keywords: Imaging diagnosis, Contrast media, Ionizing radiation, Nuclear magnetic resonance spectroscopy, X-rays, Gamma rays

OBJECTIVE: To evaluate technical factors involved in posteroanterior chest radiography in standard patients, and correlating them with entrance surface air kerma rate and with the clinical images quality. MATERIALS AND METHODS: The present study was developed at three hospitals in Rio de Janeiro, Brazil, involving a total of five x-ray rooms, with ten patients per room. The images were evaluated by the radiologists of the institutions, in accordance with the European protocol. The estimation of surface entrance air kerma rate was based on the x-ray equipment output curve obtained with an ionization chamber coupled with an electrometer. Variance analysis was performed to evaluate the significance of the difference between entrance surface air kerma rates. RESULTS: Entrance surface air kerma rates ranged between 0.05 and 0.26 mGy, with a mean value 60% lower than the reference level established by the Order (Portaria) 453. Among the images evaluated, 98% fulfilled > 65% of the images quality criteria. CONCLUSION: For a standard image quality that is acceptable for diagnosis purposes, a significant variation was observed in the entrance surface air kerma rate for standard patients, demonstrating the lack of technical factors standardization and a potential for decreasing the entrance surface air kerma rate.

Keywords: Reference levels, Optimization, Quality, Radiographic techniques

Vocal cord paralysis is a common cause of hoarseness. It may be secondary to many types of lesions along the cranial nerve X pathway and its branches, particularly the laryngeal recurrent nerves. Despite the idiopathic nature of a great number of cases, imaging methods play a very significant role in the investigation of etiologic factors, such as thyroid and esophagus neoplasias with secondary invasion of the laryngeal recurrent nerves. Other conditions such as aortic and right subclavian artery aneurysms also may be found. The knowledge of local anatomy and related diseases is of great importance for the radiologist, so that he can tailor the examination properly to allow an appropriate diagnosis and therapy planning. Additionally, considering that up to 35% of patients with vocal cord paralysis are asymptomatic, the recognition of radiological findings indicative of this condition is essential for the radiologist who must warn the referring physician on the imaging findings. In the present study, the authors review the anatomy and main diseases related to vocal cord paralysis, demonstrating them through typical cases evaluated by computed tomography and magnetic resonance imaging, besides describing radiological findings of laryngeal abnormalities indicative of this condition.

Keywords: Vocal cord, Paralysis, Imaging

Multidetector coronary computed tomography angiography is a precise method for evaluating post-coronary revascularization arterial and venous bypass grafts, and is somehow superseding coronary catheterization that is an invasive and more expensive technique. The present iconographic essay is aimed at anatomically demonstrating the bypass grafts most frequently utilized, how to differentiate between arterial and venous grafts and how to find them. The studies were performed in 64-row multidetector computed tomography equipment, with breath hold, controlled heart rate and appropriate protocols with later MPR, MIP and 3D reconstructions according to electrocardiogram. The localization of the bypass grafts and anastomoses at computed tomography studies focused on chest and coronary arteries may represent a difficulty in the images analysis by the radiologist who is not familiar with the matter, so the knowledge of the surgical techniques adopted and possible courses of the saphenous bypass grafts and arterial grafts can aid in the analysis of both studies, avoiding diagnostic errors.

Keywords: Multidetector coronary computed tomography angiography, Saphenous bypass graft, Coronary artery bypass graft

Malignant melanoma is a common and aggressive disease that frequently causes metastases to the small bowel. This study illustrates a case of small bowel intussusception secondary to metastatic melanoma visualized at 18F-FDG PET/CT in a 48-year-old woman who had this examination for restaging purposes.

Keywords: PET/CT, Melanoma, Intussusception

The present study reports the case of a 51-year-old woman with chest pain, dyspnea and upper chest vessels engorgement, with no clinical evidence of granulomatous disease. Chest imaging study revealed a mediastinal mass with calcifications that was approached by mediastinoscopy with biopsy. Histopathological study demonstrated an etiologically undefined chronic inflammatory pattern compatible with fibrosing mediastinitis.

Keywords: Fibrosing mediastinitis, Mediastinal mass, Fibrosis, Chest radiology