OBJECTIVE: The objective of this study was to describe chest computed tomography findings in confirmed cases of infection by the novel influenza A (H1N1) virus. MATERIALS AND METHODS: Computed tomography studies of nine patients with laboratory-confirmed infection by the novel influenza A (H1N1) virus were consensually evaluated by three observers. The sample of the present study included five male and four female patients with ages ranging from 14 to 64 years (mean, 40 years). Four of the patients were previously healthy, four were kidney transplant recipients and one was pregnant at the time of diagnosis. Presence, extent and distribution of the following findings were evaluated: a) ground-glass opacities; b) centrilobular nodules; c) consolidation; d) interlobular septa thickening; e) pleural effusion; f) lymphadenopathy. RESULTS: The most frequent findings were ground-glass opacities, centrilobular nodules and consolidations, present in nine (100%), five (55%) and four (44%) of cases, respectively. Pleural effusions and lymphadenopathy were less common findings, occurring in only two (22%) of the cases. CONCLUSION: Ground-glass opacities, centrilobular nodules and consolidation were the most frequent findings in cases of infection by the novel influenza A (H1N1) virus. These changes are not typical or unique to this agent and may also occur in other viral or bacterial infections.

Keywords: Influenza A virus, Influenza A (H1N1) virus subtype, Viral pneumonia, X-ray computed tomography

OBJECTIVE: Magnetic resonance imaging has been utilized in the evaluation of the lacrimal apparatus with some advantages over conventional dacryocystography. The present study was aimed at acquiring high-resolution images utilizing microscopic coils for evaluating typical structures of the lacrimal apparatus as compared with the findings observed with conventional surface coils. MATERIALS AND METHODS: Five asymptomatic volunteers with no history of epiphora were submitted to high-field magnetic resonance imaging with microscopic and conventional surface coils, and STIR sequence after instillation of saline solution. The definition of normal anatomic structures of lacrimal apparatuses was compared utilizing conventional and microscopic surface coils. Based on a consensual scoring system, the mean values for each structure were calculated by two observers. RESULTS: In 90% of cases, higher scores were attributed to images acquired with the microscopic coil. On average, a 1.17 point increase was observed in the scoring of anatomic structures imaged with the microscopic coil. Additionally, a subjective improvement was observed in the signal-to-noise ratio with the microscopic coil. CONCLUSION: Magnetic resonance dacryocystography with microscopic coils is the appropriate method for evaluating the lacrimal apparatus, providing images with better quality as compared with those acquired with conventional surface coils.

Keywords: Magnetic resonance imaging, Lacrimal apparatus, Dacryocystography, Microscopic coil

In order to evaluate atypical aspects of hepatocellular carcinoma at computed tomography and magnetic resonance imaging, we have retrospectively evaluated 100 patients with diagnosed hepatocellular carcinoma, based on combined imaging studies, laboratory results, biopsy and surgery. We have selected those cases with atypical findings at computed tomography or magnetic resonance imaging, including cystic lesions, bleeding tumors, with calcifications, with spontaneous regression, pedunculated tumors, hypovascular lesions, giant hepatocellular carcinomas, and those with unusual local invasiveness. The hepatocellular carcinoma is the most usual primary malignant lesion of the liver and usually it has a typical aspect and is associated with hepatic cirrhosis. However, in a significant number of cases, some uncommon findings can be responsible for a delayed diagnosis.

Keywords: Hepatocellular carcinoma, Liver, Atypical findings, Ultrasound, Computed tomography, Magnetic resonance imaging

In order to evaluate atypical aspects of hepatic hemangiomas at ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI), we have retrospectively analyzed 300 cases of patients diagnosed with hepatic hemangiomas by means of combined imaging studies, clinical follow-up and/or biopsy results. Based on this analysis we have selected those cases with atypical findings at one or more imaging methods or those presenting an unusual evolution such as: hypoechoic nodules at US; giant, heterogeneous hemangiomas; rapidly filling hemangiomas; calcified hemangiomas; pedunculated hemangiomas; hypointense hemangiomas at T2-weighted images; causing perfusion defect; with central scar simulating focal nodular hyperplasia; hemangiomas with adjacent abnormalities such as arterial-portal venous shunt and capsular retraction as well as hemangiomas enlarging over time. The hepatic hemangioma is the most common benign tumor affecting the liver and usually presents typical aspect. However, atypical findings should be known aiming at supporting diagnosis guidance and clinical decisions.

Keywords: Hemangioma, Liver, Atypical findings, Ultrasound, Computed tomography, Magnetic resonance imaging

OBJECTIVE: To use magnetic resonance imaging to identify vascular loops in the anterior inferior cerebellar artery and to evaluate their relationship with otologic symptoms. MATERIALS AND METHODS: We selected 33 adults with otologic complaints who underwent magnetic resonance imaging at our institution between June and November 2013. Three experienced independent observers evaluated the trajectory of the anterior inferior cerebellar artery in relation to the internal auditory meatus and graded the anterior inferior cerebellar artery vascular loops according to the Chavda classification. Kappa and chi-square tests were used. Values of p < 0.05 were considered significant. RESULTS: The interobserver agreement was moderate. Comparing ears that presented vascular loops with those that did not, we found no association with tinnitus, hearing loss, or vertigo. Similarly, we found no association between the Chavda grade and any otological symptom. CONCLUSION: Vascular loops do not appear to be associated with otoneurological manifestations.

Keywords: Arteries/anatomy & histology; Nerve compression syndromes; Magnetic resonance imaging; Tinnitus; Hearing loss; Vertigo.

OBJECTIVE: To emphasize the most appropriate magnetic resonance imaging (MRI) diffusion protocol for the detection of lesions that cause transient global amnesia, in order to perform an accurate examination, as well as to determine the ideal time point after the onset of symptoms to perform the examination. MATERIALS AND METHODS: We evaluated five patients with a diagnosis of transient global amnesia treated between 2012 and 2015. We analyzed demographic characteristics, clinical data, symptom onset, diffusion techniques, and radiological findings. Examination techniques included a standard diffusion sequence (b value = 1000 s/mm²; slice thickness = 5 mm) and a optimized diffusion sequence (b value = 2000 s/mm²; slice thickness = 3 mm). RESULTS: Brain MRI was performed at 24 h or 36 h after symptom onset, except in one patient, in whom it was performed at 12 h after (at which point no changes were seen) and repeated at 36 h after symptom onset (at which point it showed alterations in the right hippocampus). The standard and optimized diffusion sequences were both able to demonstrate focal changes in the hippocampi in all of the patients but one, in whom the changes were demonstrated only in the optimized sequence. CONCLUSION: MRI can confirm a clinical hypothesis of transient global amnesia. Knowledge of the optimal diffusion parameters and the ideal timing of diffusion-weighted imaging (> 24 h after symptom onset) are essential to improving diagnostic efficiency.

Keywords: Amnesia; Amnesia, transient global; Memory; Hippocampus; Magnetic resonance imaging; Diffusion magnetic resonance imaging.