OBJECTIVE: Juvenile myoclonic epilepsy (JME) is a subtype of genetically determined generalized epilepsy that does not present abnormalities on conventional magnetic resonance imaging. The aim of this study was to identify metabolic alterations in the thalamus in a clinically homogeneous sample of patients with easy-to-control JME, using short-echo time proton magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS: We performed single-voxel (2 cm × 2 cm × 2 cm), short-echo time (TE = 35 ms) proton MRS of the thalamus in 21 patients with JME and in 14 healthy age-matched controls. We quantified N-acetylaspartate (NAA), total NAA, creatine (Cr), choline, and myo-inositol (MI), as well as the sum of glutamate and glutamine signals, all scaled to internal water content, and we calculated metabolite ratios using Cr as a reference. Values of p < 0.05 were considered significant. RESULTS: The MI level and the MI/Cr ratio were significantly lower in the thalami of patients diagnosed with JME than in those of the controls. Other metabolites and their ratios did not differ significantly between the two groups. CONCLUSION: In our sample of 21 JME patients, we identified lower levels of MI in the thalamus. No significant abnormalities were observed in the concentrations or ratios of other metabolites.

Keywords: Myoclonic epilepsy, juvenile; Magnetic resonance spectroscopy/methods; Thalamus/abnormalities.

OBJECTIVE: To describe the spectrum of magnetic resonance imaging (MRI) findings in patients with neurological manifestations of dengue. MATERIALS AND METHODS: We included nine patients with dengue fever (three females and six males; age range, 9–30 years), all of whom presented with neurological manifestations. The MRI examinations, performed in 1.5 T or 3 T scanners, included T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) sequences. Diffusion-weighted imaging with apparent diffusion coefficient mapping was also employed. Fast low-angle shot and susceptibility-weighted gradient-recalled echo sequences, as well as contrast-enhanced T1-weighted scans, were also obtained in order to assess parenchymal enhancement. MRI scans were analyzed for lesion distribution and imaging features. RESULTS: All patients showed areas of altered signal intensity that appeared as hyperintensity on T2-weighted and FLAIR sequences. The most commonly affected site was the basal ganglia-thalamus complex. Other affected sites were the cerebellum, cerebral cortex, white matter, and brainstem. In all cases, we observed patchy areas of restricted diffusion and focal areas of hemorrhage. CONCLUSION: Dengue encephalitis commonly affects the basal ganglia, thalamus, cerebellum, cerebral cortex, and white matter. Therefore, MRI should be an indispensable part of the evaluation of patients with neurological complications of dengue fever.

Keywords: Dengue; Encephalitis; Magnetic resonance imaging; Leukoencephalitis, acute hemorrhagic; Cerebellar diseases/diagnosis.

OBJECTIVE: To assess the role of diffusion-weighted imaging (DWI) in the evaluation of breast lesions classified as suspicious on magnetic resonance imaging (MRI), correlating the findings with the results of the histological analysis. MATERIALS AND METHODS: This was a retrospective, descriptive study based on a review of the medical records of 215 patients who were submitted to MRI with DWI before undergoing biopsy at a cancer center. Apparent diffusion coefficient (ADC) values were calculated for each lesion, and the result of the histological analysis was considered the gold standard. RESULTS: The mean age was 49 years. We identified 252 lesions, 161 (63.9%) of which were found to be malignant in the histological analysis. The mean ADC value was higher for the benign lesions than for the malignant lesions (1.50 × 10^–3 mm²/s vs. 0.97 × 10⁻³ mm²/s), the difference being statistically significant (p < 0.001). The ADC cut-off point with the greatest sensitivity and specificity on the receiver operating characteristic curve was 1.03 × 10⁻³ mm²/s. When the DWI and conventional MRI findings were combined, the accuracy reached 95.9%, with a sensitivity of 95.7% and a specificity of 96.4%. CONCLUSION: The use of DWI could facilitate the characterization of breast lesions, especially those classified as BI-RADS 4, increasing the specificity and diagnostic accuracy of MRI.

Keywords: Breast neoplasms; Mammography; Ultrasonography, mammary; Magnetic resonance imaging.

OBJECTIVE: To compare the predictions of dominant Gleason pattern ≥ 4 or non-organ confined disease with Prostate Imaging Reporting and Data System (PI-RADS v2) with or without proton magnetic resonance spectroscopic imaging (¹H-MRSI). MATERIALS AND METHODS: Thirty-nine men underwent 3-tesla endorectal multiparametric MRI including ¹H-MRSI and prostatectomy. Two radiologists assigned PI-RADS v2 and ¹H-MRSI scores to index lesions. Statistical analyses used logistic regressions, receiver operating characteristic (ROC) curves, and 2x2 tables for diagnostic accuracies. RESULTS: The sensitivity and specificity of ¹H-MRSI and PI-RADS v2 for high-grade prostate cancer (PCa) were 85.7% (57.1%) and 92.9% (100%), and 56% (68.0%) and 24.0% (24.0%). The sensitivity and specificity of ¹H-MRSI and PI-RADS v2 for extra-prostatic extension (EPE) were 64.0% (40%) and 20.0% (48%), and 50.0% (57.1%) and 71.4% (64.3%). The area under the ROC curves (AUC) for prediction of high-grade prostate cancer were 0.65 and 0.61 for PI-RADS v2 and 0.72 and 0.70 when combined with ¹H-MRSI (readers 1 and 2, p = 0.04 and 0.21). For prediction of EPE the AUC were 0.54 and 0.60 for PI-RADS v2 and 0.55 and 0.61 when combined with ¹H-MRSI (p > 0.05). CONCLUSION: ¹H-MRSI might improve the discrimination of high-grade prostate cancer when combined to PI-RADS v2, particularly for PI-RADS v2 score 4 lesions, but it does not affect the prediction of EPE.

Keywords: MRI; Spectroscopy; Diagnosis; Prostate cancer; Prostatectomy.

OBJECTIVE: To evaluate the percutaneous transhepatic approach to the treatment of biliary strictures in pediatric patients undergoing liver transplantation. MATERIALS AND METHODS: This was a retrospective study of data obtained from the medical records, laboratory reports, and imaging examination reports of pediatric liver transplant recipients who underwent percutaneous transhepatic cholangiography, because of clinical suspicion of biliary strictures, between 1st September 2012 and 31 May 2015. Data were collected for 12 patients, 7 of whom were found to have biliary strictures. RESULTS: In the 7 patients with biliary strictures, a total of 21 procedures were carried out: 2 patients (28.6%) underwent the procedure twice; 3 (42.8%) underwent the procedure three times; and 2 (28.6%) underwent the procedure four times. Therefore, the mean number of procedures per patient was 3 (range, 2–4), and the average interval between them was 2.9 months (range, 0.8–9.1 months). The drainage tube remained in place for a mean of 5.8 months (range, 3.1–12.6 months). One patient presented with a major complication, hemobilia, which was treated with endovascular embolization. Clinical success was achieved in all 7 patients, and the mean follow-up after drain removal was 15.4 months (range, 5.3–26.7 months). CONCLUSION: The percutaneous transhepatic approach to treating biliary strictures in pediatric liver transplant recipients proved safe, with high rates of technical and clinical success, as well as a low rate of complications.

Keywords: Liver transplantation; Biliary atresia; Constriction, pathologic/therapy; Cholangiography; Drainage.

Although infection with the Zika virus was first recognized in 1942, it received little attention until 2007, when a true pandemic spread throughout Africa, Asia, and the Americas. Since then, numerous forms of central nervous system involvement have been described, mainly malformations related to congenital infection. Although the neuroimaging findings in congenital Zika syndrome are not pathognomonic, many are quite suggestive of the diagnosis, and radiologists should be prepared to interpret such findings accordingly. The objective of this article is to review the computed tomography and magnetic resonance imaging findings in congenital Zika syndrome.

Keywords: Magnetic resonance imaging; Computed tomography; Zika virus; Congenital Zika syndrome; Congenital infection.

Perineural tumor spread refers to the migration of tumor cells along nerve tissues. It worsens the prognosis, increases the recurrence rate, and diminishes 5-year survival by up to 30%. It is an important finding on imaging tests employed in the staging of patients with head and neck cancers, because it cannot be assessed by the surgeon alone. Nevertheless, it is frequently overlooked. In this study, we reviewed the literature regarding the imaging and pathophysiological aspects of this type of dissemination. We also analyzed ten imaging tests, obtained from a teaching hospital in Brazil, in which there were radiological signs of perineural tumor spread.

Keywords: Head and neck neoplasms/diagnosis; Diagnostic imaging; Tomography, X-ray computed; Magnetic resonance imaging.

Dizziness is a prevalent symptom in the general population, accounting for a considerable share of physician office visits, and most causes are clinically treatable. It is also a common indication for neuroimaging studies, in order to identify a specific etiology and exclude surgical causes. Here, we illustrate the main peripheral and central causes of dizziness, discussing their possible differential diagnoses, as well as their most important image aspects.

Keywords: Dizziness; Vertigo; Neuroimaging; Computed tomography; magnetic resonance imaging.

We report an unusual case of ischiofemoral impingement secondary to valgus intertrochanteric osteotomy. The osteotomy was performed for treatment of epiphysiolysis of the left femoral head.

Keywords: Femoroacetabular impingement; Ischium; Femur; Osteotomy; Hip.