OBJECTIVE: To establish the role of MRI T2-weighted sequences in the differentiation between simple cysts and hepatic hemangiomas. MATERIALS AND METHODS: A double-blinded, prospective, observational, cross-sectional study evaluated 52 patients with 91 hepatic lesions (34 simple cysts and 57 hemangiomas) submitted to abdominal magnetic resonance imaging. The combined analysis of all sequences was considered as the golden-standard. TSE sequences with long echo trains and b-FFE sequences were subjectively analyzed by two independent observers for differentiating cysts from hemangiomas. The kappa test (κ) was utilized in the analysis of the methods accuracy and inter- and intra-observer agreement (p < 0.05*). RESULTS: Cysts and hemangiomas dimensions ranged respectively between 0.5 and 6.5 cm (mean = 1.89 cm), and 0.8 and 11 cm (mean = 2.62 cm). The analysis of the sequences with long-TE and the golden-standard demonstrated a non-statistically significant agreement (κ: 0.00-0.10). The agreement between the evaluation of the b-FFE sequence and the golden-standard ranged from substantial (κ: 0.62-0.71) to almost perfect (κ: 0.86) for both observers. The inter- and intra-observer agreement for the b-FFE sequence ranged from substantial (κ: 0.62-0.70) to almost perfect (κ: 0.85-0.91). CONCLUSION: T2-weighted images acquired with the b-FFE technique present a high accuracy and reproducibility in the differentiation between cysts and hepatic hemangiomas.

Keywords: Liver, Cyst, Hemangioma, Magnetic resonance imaging

OBJECTIVE: The present study was aimed at evaluating the accuracy of magnetic resonance cholangiography in the assessment of the biliary anatomy in living liver donors in correlation with surgical findings. MATERIALS AND METHODS: Fifty living liver donors were retrospectively evaluated at Hospital de Clínicas da Universidade Federal do Paraná, Curitiba, PR, Brazil. Cholangiographic images were analyzed and results were compared with intraoperative findings. Only anatomical alterations that affected the surgical strategy and had not been previously observed at magnetic resonance cholangiography were considered as being in disagreement. RESULTS: Anatomical variations were found in 7 donors at magnetic resonance cholangiography, and in 14 during surgery. Agreement between imaging and surgical findings was observed in 41 of the 50 patients, and disagreement in 9. Magnetic resonance cholangiography sensitivity, specificity, positive and negative predictive values, and accuracy were respectively 43%, 97%, 86%, 81% and 81.6%. CONCLUSION: Magnetic resonance imaging is a safe and noninvase method for preoperative evaluation of the biliary tract in living liver donors. However some anatomical abnormalities are not detected by magnetic resonance cholangiography.

Keywords: Liver transplant, Living donors, Magnetic resonance imaging, Biliary tract

OBJECTIVE: To compare low-field (0.2 T) with high-field (1.5 T) magnetic resonance imaging in the assessment of pelvic endometriosis and adenomyosis. MATERIALS AND METHODS: Twenty-seven female patients with clinically suspected endometriosis were prospectively evaluated by means of high-field and low-field magnetic resonance imaging. The reading of the images was performed by a single radiologist, initiating by the low-field, followed by the high-field images. High-field magnetic resonance imaging was utilized as the golden-standard. RESULTS: Among the 27 patients included in the present study, 18 (66.7%) had some type of lesion suggesting the presence of endometriosis demonstrated at high-field images. In 14 of these patients the diagnosis was correctly established by low-field magnetic resonance imaging. Endometriomas, tubal lesions, and endometriotic foci > 7 mm identified at the high-field images were also identified at low-field images with 100% accuracy, sensitivity and specificity. Among the nine patients diagnosed with adenomyosis by high-field images, eight were correctly diagnosed by low-field images with 88.9% accuracy, specificity and sensitivity. CONCLUSION: Low-field magnetic resonance imaging demonstrated a low sensitivity in the detection of small endometriotic foci, high sensitivity in the detection of endometriomas and large endometriotic foci, and high accuracy in the detection of adenomyosis when compared with high-field magnetic resonance imaging.

Keywords: Magnetic resonance imaging, Endometriosis, Adenomyosis, Diagnosis

OBJECTIVE: To correlate imaging findings of medulloblastomas at conventional magnetic resonance imaging, diffusion-weighted imaging and proton magnetic resonance spectroscopy, comparing them with data in the literature. MATERIALS AND METHODS: Preoperative magnetic resonance imaging studies of nine pediatric patients with histologically confirmed medulloblastomas (eight desmoplastic medulloblastoma, and one giant cell medulloblastoma) were retrospectively reviewed, considering demographics as well as tumors characteristics such as localization, morphology, signal intensity, contrast-enhancement, dissemination, and diffusion-weighted imaging and spectroscopy findings. RESULTS: In most of cases the tumors were centered in the cerebellar vermis (77.8%), predominantly solid (88.9%), hypointense on T1-weighted images and intermediate/hyperintense on T2-FLAIR-weighted images, with heterogeneous enhancement (100%), tumor dissemination/extension (77.8%) and limited water molecule mobility (100%). Proton spectroscopy acquired with STEAM technique (n = 6) demonstrated decreased Naa/Cr ratio (83.3%) and increased Co/Cr (100%) and mI/Cr (66.7%) ratios; and with PRESS technique (n = 7) demonstrated lactate peak (57.1%). CONCLUSION: Macroscopic magnetic resonance imaging findings in association with biochemical features of medulloblastomas have been useful in the differentiation among the most frequent posterior fossa tumors.

Keywords: Medulloblastoma, Infratentorial neoplasms, Pediatric brain tumors, Magnetic resonance imaging, Diffusion-weighted magnetic resonance imaging, Magnetic resonance spectroscopy

OBJECTIVE: To evaluate radiological findings in patients submitted to surgical treatment for medullary breast cancer at Instituto Nacional de Câncer (INCA), Rio de Janeiro, RJ, Brazil, correlating them with histological results. MATERIALS AND METHODS: A retrospective descriptive study was developed with patients submitted to surgery at INCA, in the period from January 1997 to December 2006, for identifying the presence of medullary breast carcinoma and analyzing radiological findings. RESULTS: Among 21,287 patients diagnosed with carcinoma, 76 (0.357%) had typical medullary breast carcinoma. The age range of these patients was 32-81 years (mean = 59.1 years). Mammography demonstrated lesions in 19 of these patients, 17 (89.5%) of them with masses, and 2 with focal asymmetry. Among the patients with masses, 15 (88.1%) presented with high density and 2 (11.9%) with isodensity. Twelve patients presented sonographic findings, 11 (91.6%) of them with hypoechoic masses, and one with an anechoic mass with areas of cystic degeneration. CONCLUSION: Nodular mass was the predominant radiological finding (89.5%), 88.1% of them corresponding to masses with high density and circumscribed margins. Despite the radiological characteristics of benignity, a solid, fast-growing, highly dense mass with circumscribed margins should be further investigated to confirm the diagnosis.

Keywords: Medullary breast cancer, Radiological findings, Diagnosis

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: A software called QualIM® - Qualificação de Imagens Médicas was developed for training of practitioners in the interpretation of digital mammograms classified according to BI-RADS® categories, utilizing images manipulation tools on state-of-the-art displays. MATERIALS ANDMETHODS: A Delphi 7-based system stores data resulting from mammographic findings interpretation during the training, comparing them with a golden-standard data set. The database includes computed radiography, direct radiography and digitized images. The software converts computed radiography and direct radiography images into TIFF format, preserving their original spatial and contrast resolution. During the training, the images are manipulated with the aid of the software tools (zoom, inversion, digital rulers and others). Depending on the image complexity, up to eight mammographic views, six ultrasonography images and two anatomopathological images can be displayed. RESULTS: The training was initiated in 2007 and is currently included in the radiology residency program. Based on data entered by the practitioner, the software automatically generates a BI-RADS compliant text that is compared with a database. CONCLUSION: The QualIM software is a digital educational tool aimed at assisting practitioners in the recognition of visual patterns on mammographic images as well as in the interpretation of mammograms based on the BI-RADS classification.

Keywords: Training, Digital mammography, Displays

OBJECTIVE: To develop an atlas of myocardial perfusion scintigraphy and evaluating its applicability in computer-aided detection of myocardial perfusion defects in patients with ischemic heart disease. MATERIALS AND METHODS: The atlas was created with rest-stress myocardial perfusion scintigraphic images of 20 patients of both genders with low probability of coronary artery disease and considered as normal by two experienced observers. Techniques of image registration and mathematical operations on images were utilized for obtaining template images depicting mean myocardial uptake and standard deviation for each gender and physiological condition. RESULTS: Myocardial perfusion scintigraphy images of one male and one female patient were aligned with the corresponding atlas template image, and voxels with myocardial uptake rates two standard deviations below the mean voxel value of the respective region in the atlas template image were highlighted on the tomographic sections and confirmed as perfusion defects by both observers. CONCLUSION: The present study demonstrated the creation of an atlas of myocardial perfusion scintigraphy with promising results of this tool as an aid in the detection of myocardial perfusion defects. However, further prospective validation with a more representative sample is recommended.

Keywords: Scintigraphy, SPECT, Myocardium, Nuclear medicine, Computer-assisted image processing, Computer-assisted diagnosis

Chronic autoimmune thyroiditis is currently considered as the main cause for hypothyroidism and its diagnosis is based on clinical manifestations and laboratory tests results. The most significant laboratory marker for this disease is the presence of anti-thyroperoxidase and anti-thyroglobulin antibodies, the latter being the most sensitive one. Aspiration biopsy shows high sensitivity and specificity but, considering the invasiveness of this method it is reserved for cases of suspected nodules or fast growing goiter. Scintigraphy is unnecessary for the diagnosis, considering its low specificity and sensitivity. Both B-mode and duplex color Doppler ultrasonography have rapidly evolved, becoming a simple, noninvasive and reproducible method with high sensitivity for the diagnosis of chronic autoimmune thyroiditis. Echogenicity is a relevant parameter at B-mode ultrasonography because of the close correlation with cytopathological findings besides the high sensitivity in the diagnosis of the disease. Although this is not a specific parameter for chronic autoimmune thyroiditis, considering that it may also be found in Graves' disease, postpartum thyroiditis and subacute thyroiditis, such disorders can be easily differentiated both by clinical-laboratory and duplex color Doppler findings. Thus, the present study is aimed at evaluating the significance of thyroid echogenicity in the diagnosis of chronic autoimmune thyroiditis.

Keywords: Ultrasonography, Echogenicity, Thyroiditis, Chronic, Autoimmune

We describe imaging findings of a oesophageal liposarcoma in a 66 year old man. The computed tomography scan was performed after a chest radiograph showed a large posterior mediastinal mass. Oesophageal liposarcomas are rare tumours. They can achieve large size before they become symptomatic. Our patient was successfully managed with complete surgical removal.

Keywords: Liposarcoma, Oesophagus, Computed tomography scan