Radiologia Brasileira最新文献

Objective: To assess the intensity, characteristics, and distribution of computed tomography (CT) findings of pulmonary involvement, as well as to evaluate laboratory test results, in health care professionals who were exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Materials and methods: This was a retrospective, cross-sectional, observational study based on the analysis of laboratory test results and chest CT images of health care workers with confirmed coronavirus disease 2019 (COVID-19). Data for the period from March 2020 to December 2022 were collected from two hospitals in Brazil.

Results: We identified 1,091 health care professionals in whom a RT-PCR was positive for SARS-CoV-2. However, only 38 of those individuals underwent chest CT. Of the 38 individuals evaluated, 89.5% were treated at one of the hospitals and 57.9% were male. The mean age was 55.6 years. The most common finding (in 100% of the cases) was ground-glass opacity, followed by septal thickening (in 31.6%) and consolidation (in 23.7%). Pulmonary involvement was multifocal in 76.3% and predominantly subpleural in 71.0%. The extent of the involvement was classified as mild in 24% of the cases, moderate in 47%, and severe in 29%. The most commonly affected lung region (in 60.7% of cases) was the lower lobes, particularly the right posterior basal segmental bronchus (segment B10).

Conclusion: For evaluating lung involvement, CT was essential, aiding in postinfection monitoring and in the early management of complications. Among the health care professionals evaluated, moderate involvement predominated.

Objective: To evaluate the positive predictive value (PPV) of the imaging characteristics of breast lesions classified as BI-RADS category 4 (risk of malignancy > 2% to < 95%) on magnetic resonance imaging (MRI), in order to create an algorithm to subcategorize such lesions.

Materials and methods: This was a retrospective study including 199 breast lesions (131 nodules and 68 non-mass lesions) classified as BI-RADS 4 on MRI. Of the 199 lesions, 93 were excluded, for various reasons: they were lymph nodes; they were not biopsied or were not followed at our center; they were additional findings in patients with an established diagnosis of malignancy who underwent mastectomy without further investigation; or they were identified in examinations that were not recovered from the digital archive. Multivariate analysis was performed to identify the most relevant descriptors to predict malignancy and to build an algorithm to subcategorize lesions into BI-RADS 4A, 4B, and 4C. Four breast radiologists then tested the algorithm in another 95 patients with breast lesions classified as BI-RADS 4 on MRI, 27 (28.4%) of those lesions having previously been classified as malignant.

Results: The descriptors statistically associated with malignancy in the multivariate analysis of the nodules were background parenchymal enhancement, margins, and the initial phase of the kinetic curve. An algorithm was developed by using these resources, and the PPV obtained for each category was 4.3% for BI-RADS 4A, 21.4% for BI-RADS 4B, and 78.9% for BI-RADS 4C. In the validation of the algorithm by the four breast radiologists, the PPV of the subcategories was within the BI-RADS malignancy ranges in almost all situations, the exceptions being the 11.1% that one evaluator obtained for category 4A and the 46.4% obtained for category 4C by another evaluator.

Conclusion: The objective analysis employing the proposed algorithm proved useful for subdividing BI-RADS 4 mass lesions on MRI and showed better interobserver agreement than did the subjective analysis.

Pituitary neuroendocrine tumors, previously known as pituitary adenomas, are the most common pituitary gland tumors; when larger than 10 mm in diameter, they are called pituitary macroadenomas. Although most pituitary macroadenomas exhibit characteristic imaging features, some present with uncommon neuroimaging manifestations. Less common imaging manifestations include hemorrhage, areas of necrosis, cystic components, calcifications, bone invasion, and extrasellar location. Knowing how to recognize the atypical neuroimaging patterns of pituitary macroadenomas is also crucial for identifying the potential aggressive behavior of the lesion. In addition to predicting aggressive behavior, recognition of atypical neuroimaging characteristics can help the neurosurgeon determine the most effective surgical approach. The aim of this review was to highlight the less common imaging patterns of pituitary macroadenomas.

Objective: To evaluate the diagnostic accuracy of computed tomography (CT) for detecting osteoporosis in Brazilian adults, using dual-energy X-ray absorptiometry (DXA) as the reference standard.

Materials and methods: We conducted a retrospective analysis of adults over 50 years of age who underwent CT (chest, abdominal, or lumbar scans) and DXA within a 60-day interval, between January 2012 and December 2022. Vertebral bone attenuation at L1 was quantified in Hounsfield units. Thresholds of > 160 HU and < 100 HU were used in order to classify bone as normal and osteoporotic, respectively. Two musculoskeletal radiologists, working independently, performed subjective classifications. Sensitivity, specificity, predictive values, and interobserver agreement (Cohen's kappa) were calculated. The influence of contrast use and scanner heterogeneity was considered.

Results: Ninety-five patients met the inclusion criteria. On the basis of the DXA results, we identified 39 normal cases, 46 cases of osteopenia, and 10 cases of osteoporosis. For detecting normal bone, objective CT measurements demonstrated a sensitivity of 88.6% and a specificity of 95.5%. For detecting osteoporosis, the sensitivity was 75.3% and the specificity was 99.7%. For the subjective classification, the level of interobserver agreement was fair (κappa = 0.384). The study included CT scans from different scanner models, with and without contrast enhancement.

Conclusion: Opportunistic CT demonstrated high specificity but only moderate sensitivity for osteoporosis detection. The attenuation thresholds previously validated in populations elsewhere show promise for use in Brazil. However, scanner variability, contrast use, and limited sample size constrain generalizability. Larger, multicenter prospective studies are warranted.

Imaging plays a critical role in the assessment of patients with rectal cancer, and positron emission tomography/magnetic resonance imaging (PET/MRI) has shown superiority in specific clinical scenarios. This review describes the potential contribution of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET/MRI relative to standard of care imaging-computed tomography (CT), MRI, or PET/CT-in the evaluation of patients with rectal cancer in settings such as primary staging, treatment response assessment, and recurrence detection. We discuss ¹⁸F-FDG PET/MRI protocols and clinical workflow, as well as highlighting the potential clinical superiority of PET/MRI over other imaging modalities.

Objective: To evaluate, primarily, the accuracy of plain radiography (X-ray) in diagnosing apophyseal avulsion fractures in adolescent soccer players, using magnetic resonance imaging (MRI) as the gold standard. As secondary objectives, we investigated associations between findings on X-ray, MRI, and power Doppler, as well as the imaging features that distinguish avulsion fractures from apophysitis.

Materials and methods: This was an observational cross-sectional study involving 33 male athletes 9-17 years of age with clinical suspicion of an apophyseal avulsion fracture. Imaging examinations were performed within the first 24 h after the trauma. We evaluated diagnostic reproducibility among readers, the accuracy of X-ray compared with MRI, and the associations between findings from different imaging methods.

Results: We found that X-ray had an accuracy of 56.0%, with high specificity (71.4%) and positive predictive value (81.8%), although its sensitivity and negative predictive value were relatively low (50.0% and 35.7%, respectively). The power Doppler result was significantly associated with avulsion fractures detected on MRI (p = 0.0144). Avulsion fractures were associated with periphyseal edema and intermuscular fluid collections, while apophysitis was associated with bone marrow edema.

Conclusion: X-ray is useful for confirming, but not for excluding, avulsion fractures. Power Doppler and MRI contribute to the differential diagnosis.

Objective: To develop and evaluate the use of radiation shields for patients undergoing coronary angiography via the radial approach.

Materials and methods: Two pelvic-abdominal shields were developed-one for the posterior region and one for the anterior region. To analyze the entrance dose and its attenuation through the patient until reaching a detector as residual radiation, two dosimeter strips (right and left) were created and inserted into a phantom.

Results: Comparing the shielded and unshielded groups, we found that the radiation doses at all detector positions were significantly higher in the shielded group (p < 0.0001).

Conclusion: The use of pelvic-abdominal radiation shields made with 0.5 mm of lead is not recommended for patients undergoing interventional cardiology procedures, because it significantly increases radiation exposure and therefore does not comply with the As Low as Reasonably Achievable principle.