OBJECTIVE: To report the computed tomography (CT) features of acute cerebrovascular complications in severely ill patients with confirmed coronavirus disease 2019 (COVID-19) in the intensive care unit. MATERIALS AND METHODS: We conducted a retrospective analysis of 29 intensive care unit patients with confirmed COVID-19 who underwent CT of the brain. We describe the CT features of the cerebrovascular complications of COVID-19, as well the demographic characteristics and clinical features, together with the results of laboratory tests, such as complete blood cell count, coagulation testing, renal function testing, and C-reactive protein assay. RESULTS: Two patients were excluded because of brain death. Among the remaining 27 patients, CT revealed acute cerebrovascular complications in six (three men and three women; 49–81 years of age), whereas no such complications were seen in 21 (15 men and six women; 36–82 years of age). CONCLUSION: Radiologists should be aware of the risks of cerebrovascular complications of COVID-19 and the potential underlying etiologies. COVID-19–associated coagulopathy is likely multifactorial and may increase the risk of ischemic and hemorrhagic infarction.

Keywords: Coronavirus infections/complications; Cerebrovascular disorders; Blood coagulation disorders; Tomography, X-ray computed.

Objective: To determine whether the whole-body tumor burden, as quantified by ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT), is a prognostic indicator in advanced (stage III or IV) non-small cell lung cancer (NSCLC). Materials and Methods: This was a prospective study in which we evaluated ¹⁸F-FDG PET/CT staging parameters to quantify tumor burdens in patients with stage III or IV NSCLC. The following parameters were evaluated for the whole body (including the primary tumor) and for the primary tumor alone, respectively: maximum standardized uptake volume (wbSUV_max and tuSUV_max); metabolic tumor volume (wbMTV and tuMTV); and total lesion glycolysis (wbTLG and tuTLG). To determine whether the ¹⁸F-FDG PET/CT parameters were associated with overall survival (OS) and progression-free survival (PFS), we evaluated the wbSUV_max/tuSUV_max, wbMTV/tuMTV, and wbTLG/tuTLG ratios. Results: ¹⁸F-FDG PET/CT was performed for staging in 52 patients who were followed for a median of 11.0 months (mean, 11.7 months). The estimated median PFS and OS were 9.6 months and 11.6 months, respectively. In the univariate analysis, OS was found to correlate significantly with wbTLG (hazard ratio [HR] = 1.001; 95% confidence interval [95 CI]: 1.000–1.001; p = 0.0361) and with the wbTLG/tuTLG ratio (HR = 1.705; 95% CI: 1.232–2.362; p = 0.0013). In the multivariate analysis, only the wbTLG/tuTLG ratio was independently associated with OS (HR = 1.660; 95% CI: 1.193–2.310; p = 0.0027). Conclusion: The wbTLG/tuTLG ratio is an independent prognostic indicator of OS in advanced-stage NSCLC.

Keywords: Fluorodeoxyglucose F18; Positron-emission tomography/methods; Tomography, X-ray computed/methods; Carcinoma, non-small-cell lung/diagnosis; Tumor burden; Carcinoma, non-small-cell lung/mortality.

OBJECTIVE: To assess the technique, efficacy, and safety of computed tomography (CT)-guided percutaneous biopsies of head and neck masses. MATERIALS AND METHODS: This was a retrospective, single-center study of CT-guided percutaneous core-needle biopsies of head and neck masses.For the analysis of diagnostic accuracy, biopsy results were compared with the final diagnosis, which was determined by histological examination and clinical follow-up. RESULTS: We evaluated 74 biopsies performed in 68 patients.The mean age of the patients was 55.6 years.Most of the lesions (79.7%) were located in the suprahyoid region, and the maximum diameter ranged from 11 mm to 128 mm.The most common approaches were paramaxillary (in 32.4%), retromandibular (in 21.6%), and periorbital (in 14.9%).Five patients (6.8%) developed minor complications.The presence of a complication did not show a statistically significant association with any clinical, radiological, or procedure-related factor.Sufficient material for histological analysis was obtained in all procedures.Thirty-eight biopsies (51.4%) yielded a histological diagnosis of malignancy.There was a false-negative result in three cases (8.3%), and there were no false-positive results.The procedure had a sensitivity of 92.7%, a specificity of 100%, and an accuracy of 96.0%. CONCLUSION: Our results demonstrate that CT-guided percutaneous core-needle biopsy of head and neck lesions is a safe, effective procedure for obtaining biological material for histological analysis.

Keywords: Image-guided biopsy; Needle biopsy; Tomography, X-ray computed; Head and neck neoplasms.

OBJECTIVE: To evaluate qualitative and quantitative magnetic resonance imaging (MRI) criteria for injury of the common peroneal nerve (CPN) in patients with acute or subacute injuries in the posterolateral corner (PLC) of the knee, as well as to evaluate the reproducibility of MRI evaluation of CPN alterations. MATERIALS AND METHODS: This was a retrospective study of 38 consecutive patients submitted to MRI and diagnosed with acute or subacute injury to the PLC of the knee (patient group) and 38 patients with normal MRI results (control group).Two musculoskeletal radiologists (designated radiologist A and radiologist B, respectively) evaluated the images.Nerve injury was classified as neurapraxia, axonotmesis, or neurotmesis.Signal strength was measured at the CPN, the tibial nerve (TN), and a superficial vein (SV).The CPN/TN and CPN/SV signal ratios were calculated.The status of each PLC structure, including the popliteal tendon, arcuate ligament, lateral collateral ligament, and biceps tendon, was classified as normal, partially torn, or completely torn, as was that of the cruciate ligaments.For the semiquantitative analysis of interobserver agreement, the kappa statistic was calculated, whereas a receiver operating characteristic (ROC) curve was used for the quantitative analysis. RESULTS: In the patient group, radiologist A found CPN abnormalities in 15 cases (39.4%)—neurapraxia in eight and axonotmesis in seven—whereas radiologist B found CPN abnormalities in 14 (36.8%)—neurapraxia in nine and axonotmesis in five.The kappa statistic showed excellent interobserver agreement.In the control group, the CPN/TN signal ratio ranged from 0.63 to 1.1 and the CPN/SV signal ratio ranged from 0.16 to 0.41, compared with 1.30–4.02 and 0.27–1.08, respectively, in the patient group.The ROC curve analysis demonstrated that the CPN/TN signal ratio at a cutoff value of 1.39 had high (93.3%) specificity for the identification of nerve damage, compared with 81.3% for the CPN/SV signal ratio at a cutoff value of 0.41. CONCLUSION: CPN alterations are common in patients with PLC injury detected on MRI, and the level of interobserver agreement for such alterations was excellent.Calculating the CPN/TN and CPN/SV signal ratios may increase diagnostic confidence.We recommend systematic analysis of the CPN in cases of PLC injury.

Keywords: Peroneal nerve/diagnostic imaging; Knee injuries/diagnostic imaging; Knee/innervation; Magnetic resonance imaging.

OBJECTIVE: To evaluate the success and complication rates of ultrasound-guided renal biopsy at a tertiary care hospital. MATERIALS AND METHODS: This was a retrospective analysis of 97 ultrasound-guided renal biopsies, all performed by the same radiologist, between 1 March, 2017 and 31 October, 2019. RESULTS: Of the 97 biopsies evaluated, 87 had a definitive pathological diagnosis. In five cases (5.4%), the biopsy results were inconclusive and a second procedure was required. In seven procedures (7.6%), there were complications, all of which were properly resolved. CONCLUSION: Ultrasound-guided renal biopsy has proven to be a safe, effective method for the diagnosis of nephropathies, with high success rates.

Keywords: Biopsy, needle/methods; Kidney diseases/epidemiology; Kidney glomerulus/pathology; Ultrasonography, interventional.

Although contrast-enhanced ultrasound has been shown to provide considerable benefits, particularly in pediatric patients, it is still used relatively rarely in Brazil. It has proven to be a safe technique, and adverse effects are rare. In this review, we address the technique and main applications of contrast-enhanced ultrasound in the pediatric population, including the evaluation of focal liver lesions, abdominal trauma, kidney grafts, liver grafts, bowel loops, and vesicoureteral reflux. It is important for pediatric radiologists to be acquainted with this promising tool, understanding its applications and limitations.

Keywords: Pediatrics; Ultrasonography; Contrast media; Microbubbles.

Whole-body magnetic resonance imaging (WB-MRI) is a noninvasive imaging method that can be used to diagnose and stage tumors, as well as to assess therapeutic responses in oncology. The objective of this meta-analysis was to evaluate the accuracy of WB-MRI for the diagnosis of metastases in pediatric patients. The following electronic databases were searched: Medline, Embase, Cochrane Central Register of Controlled Trials, Scientific Electronic Library Online, Latin-American and Caribbean Health Sciences Literature, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and ClinicalTrials.gov. All of the selected studies included children and adolescents with histopathological confirmation of a primary tumor. Collectively, the studies included 118 patients ranging in age from 7 months to 19 years. The pooled sensitivity and specificity of WB-MRI were, respectively, 0.964 (95% CI: 0.944–0.978; I² = 0%) and 0.902 (95% CI: 0.882–0.919; I² = 98.4%), with an area under the curve (AUC) of 0.991. We found that WB-MRI had good accuracy for the diagnosis of metastases in pediatric patients and could therefore provide an alternative to complete the staging of tumors in such patients, being a safer option because it does not involve the use of ionizing radiation.

Keywords: Whole body imaging/methods; Magnetic resonance imaging/methods; Neoplasms/diagnostic imaging; Meta-analysis; Pediatrics.

Vanishing bone metastasis (pseudopathological vertebral body enhancement) is a pitfall in the interpretation of contrast-enhanced computed tomography (CT) scans of patients with thoracic vein obstruction, mainly in the superior vena cava and brachiocephalic veins, typically being related to thrombosis due to malignant tumors. On the basis of the CT findings, pseudopathological vertebral body enhancement can be misdiagnosed as sclerotic bone metastasis, leading to unnecessary treatment. Although not rare, pseudopathological vertebral body enhancement is usually underdiagnosed by radiologists. The aim of this study is to review the pathophysiology of this phenomenon, illustrating the most common collateral venous pathways in thoracic vein obstruction and making the correlation with the CT findings.

Keywords: Neoplasm metastasis/physiopathology; Bone and bones/diagnostic imaging; Tomography, X-ray computed; Diagnostic errors; Venous thrombosis; Collateral circulation.

The diseases that affect the thalamus are heterogeneous in their etiologies, including infectious, inflammatory, vascular, toxic-metabolic, and neoplastic causes. It is often difficult to make the clinical differentiation between different entities. Within this context, computed tomography and magnetic resonance imaging have come to be of fundamental importance for defining the etiology and planning the treatment. In this pictorial essay, we will illustrate the main causes of diseases affecting the thalamus, discussing the possible differential diagnoses, as well as the most relevant imaging aspects.

Keywords: Thalamus; Magnetic resonance imaging; Tomography, X-ray computed; Demyelinating diseases; Infections.