Romeu Côrtes Domingues

Assessment of Breast Lesions With Diffusion-Weighted MRI: Comparing the Use of Different b Values

OBJECTIVE Our purpose was to study the utility of diffusion-weighted MRI in differentiating benign from malignant breast lesions by assessing the best b values. SUBJECTS AND METHODS Forty-five women (mean age, 46.1 years) with 52 focal mass breast lesions underwent diffusion-weighted imaging with different b values. The apparent diffusion coefficient (ADC) value of each lesion was calculated from the ADC maps done using five b values (0, 250, 500, 750, and 1,000 s/mm(2)) and using b values of 0 s/mm(2) with each other b value separately (0 and 250 s/mm(2), 0 and 500 s/mm(2), 0 and 750 s/mm(2), 0 and 1,000 s/mm(2)). The mean ADC values were correlated with imaging findings and histopathologic diagnoses. The cutoff ADC value, sensitivity, and specificity of diffusion-weighted imaging to differentiate benign and malignant lesions were calculated in all b value combinations. A p value of < 0.05 was considered statistically significant. RESULTS The mean ADC value was significantly lower for malignant lesions compared to benign lesions (p < 0.0001) in all b value combinations. No statistical difference was seen between the ADC obtained from different b value combinations (p = 0.2581) in the differentiation between benign and malignant lesions. The ADC calculated from b 0 and 750 s/mm(2) was slightly better than the other b value combinations, showing a sensitivity of 92.3% and a specificity of 96.2%. CONCLUSION Diffusion-weighted imaging is a potential resource as a coadjutant of MRI in the differentiation between benign and malignant lesions. Such imaging can be performed without a significant increase in examination time, especially because it can be done with lower b values.

Diffusion Tensor Imaging Findings in School-Aged Autistic Children

To analyze and compare cerebral white matter tracts through diffusion tensor imaging in autistic and normal children.

Early diagnosis of pediatric wernicke’s encephalopathy

Wernickes encephalopathy may be fatal if untreated. Because Wernickes encephalopathy is suspected to be underdiagnosed in children, the authors wished to assess the frequency of overlooked diagnosis and to establish pertinent findings that could lead to early identification of pediatric Wernickes encephalopathy. The authors performed multiple literature searches seeking pediatric patients with Wernickes encephalopathy (age = 20 years or younger). A total of 30 patients was found, and the authors added a new patient. Each case report had its clinical, radiologic, and laboratory data, diagnostic method, and outcome analyzed. Of 31 patients, 16 were female and 15 male; the median age +/- S.D. was 11 +/- 6.5 years. The most frequent underlying disorder was malignancy in 11. Thirteen patients died undiagnosed, 16 recovered with thiamine therapy (eight with sequelae), and two died of infection soon after thiamine replacement was initiated. Only six presented with the Wernickes encephalopathy clinical triad (mental status changes, ocular signs, and ataxia) at neurologic onset; nine eventually demonstrated this triad. The high rate of patients diagnosed only at postmortem examination (41.9%) confirms that Wernickes encephalopathy is underdiagnosed in children. Thiamine therapy is warranted if any component of the Wernickes encephalopathy triad is present in an appropriate clinical setting.

MR Imaging in Deep Pelvic Endometriosis: A Pictorial Essay

Deep pelvic endometriosis is an important gynecologic disorder that is responsible for severe pelvic pain and is defined as subperitoneal invasion that exceeds 5 mm in depth. Deep pelvic endometriosis can affect the retrocervical region, uterosacral ligaments, rectum, rectovaginal septum, vagina, urinary tract, and other extraperitoneal pelvic sites. It is commonly associated with dysmenorrhea, dyspareunia, pelvic pain, urinary tract symptoms, and infertility. Because surgery remains the best therapeutic option for affected patients, the accurate preoperative assessment of the extension of endometriotic disease is extremely important. Pelvic magnetic resonance (MR) imaging is a noninvasive method with high spatial resolution that allows multiplanar evaluation of deep pelvic endometriosis and good tissue characterization, but without the use of ionizing radiation or iodinated contrast agents. MR imaging yields important findings that help grade the disease and identify subperitoneal lesion extension and other associated disease entities, thereby facilitating accurate diagnosis and adequate treatment. Radiologists should be familiar with the MR imaging findings of deep infiltrating endometriosis in various anatomic locations so that they can provide information that allows adequate presurgical counseling.

Potential Role of Diffusion Tensor MRI in the Differential Diagnosis of Mild Cognitive Impairment and Alzheimer's Disease

OBJECTIVE The purpose of this study was to evaluate the fractional anisotropy values of several white matter tracts with the aim of differentiating a healthy population from persons with mild cognitive impairment or Alzheimers disease. SUBJECTS AND METHODS Seventy-nine patients with memory impairment and 16 volunteer controls participated in the study. MRI was performed with a 1.5-T system. Conventional MR images and diffusion tensor images were obtained for all participants. The diffusion tensor imaging data were postprocessed, and low b-value, fractional anisotropy, and fractional anisotropy color-coded maps were calculated. With the three maps as an anatomic reference, fractional anisotropy was measured for hippocampal formations, superior longitudinal fascicles, posterior cingulate gyri, and the splenium of the corpus callosum. Kruskal-Wallis and Steel-type multiple-comparison nonparametric tests were performed for the statistical analysis. RESULTS The fractional anisotropy values for the splenium of the corpus callosum, bilateral posterior cingulate gyri, and bilateral superior longitudinal fascicles of patients with mild cognitive impairment and those with probable Alzheimers disease were significantly lower than the values of controls. No differences were found in hippocampal formations in any group. No significant difference was found in fractional anisotropy values in comparisons of mild cognitive impairment versus possible Alzheimers disease and probable Alzheimers disease or comparisons of probable Alzheimers disease and possible Alzheimers disease. CONCLUSION Diffusion tensor imaging is a promising technique for the evaluation of patients with probable mild cognitive impairment. Early detection of the disease expands the treatment options, increasing the likelihood of a good clinical response and enhancing the quality of life of patients and their relatives. Further studies with larger populations are needed to confirm the role of diffusion tensor imaging in the evaluation of memory impairment.

Evaluation of hippocampal volume based on MR imaging in patients with bipolar affective disorder applying manual and automatic segmentation techniques.

To compare the hippocampal volumes in patients with bipolar disorder (BD) and healthy controls, obtained by applying different segmentation methods (manual, Freesurfer [FS], and FSL).

Congenital Chest Malformations: A Multimodality Approach with Emphasis on Fetal MR Imaging

Congenital chest malformations can range from small and asymptomatic entities to large space-occupying masses that require immediate surgical treatment. They may affect the foregut, pulmonary airway, and vasculature. Hybrid conditions are commonly seen, with interrelated chest malformations having various radiologic and pathologic features. An understanding of the in utero complications associated with fetal chest masses is essential for appropriate monitoring during pregnancy, treatment recommendations, and delivery management. Technologic advances have greatly improved the diagnosis of fetal anomalies. Congenital chest malformations are usually evaluated in the prenatal period with fetal sonography, but fetal magnetic resonance (MR) imaging is a well-established modality that is used as an adjunct technique in difficult diagnostic situations. MR imaging can provide excellent tissue contrast with more accurate analysis of the fetal anatomy and superior differentiation between the abnormalitites and adjacent structures, thereby allowing early planning of prenatal management.

Whole-body MRI and FDG PET fused images for evaluation of patients with cancer.

OBJECTIVE The purpose of this article is to illustrate the feasibility of fused whole-body MRI and PET for the evaluation of patients with cancer. CONCLUSION MRI has proven to be superior to CT for studying several regions of the body, and PET FDG has become an established diagnostic tool in oncology. Because FDG accumulates avidly in tumor tissue, fusing FDG PET to whole-body MRI allows good anatomy-based evaluation of disease.

PET/CT and vascular disease: current concepts.

Since its introduction in 2001, positron emission tomography associated to computed tomography (PET/CT) has been established as a standard tool in cancer evaluation. Being a multimodality imaging method, it combines in a single session the sensitivity granted by PET for detection of molecular targets within the picomolar range, with an underlying submilimetric resolution inherent to CT, that can precisely localize the PET findings. In this last decade, there have been new insights regarding the pathophysiology of atherosclerosis, particularly about plaque rupture and vascular remodeling. This has increased the interest for research on PET/CT in vascular diseases as a potential new diagnostic tool, since some PET molecular targets could identify diseases before the manifestation of gross anatomic features. In this review, we will describe the current applications of PET/CT in vascular diseases, emphasizing its usefulness in the settings of vasculitis, aneurysms, vascular graft infection, aortic dissection, and atherosclerosis/plaque vulnerability. Although not being properly peripheral vascular conditions, ischemic cardiovascular disease and cerebrovascular disease will be briefly addressed as well, due to their widespread prevalence and importance.

Proton magnetic resonance spectroscopy in school-aged autistic children.

This study aims to assess cerebral metabolites in school‐aged autistic patients through proton magnetic resonance spectroscopy.