OBJECTIVE: To evaluate the usefulness of elastography (using manual compression) as an additional diagnostic tool for children and adolescents with thyroid nodules. MATERIALS AND METHODS: This was a prospective study conducted between September 2012 and August 2013 at a hospital in Brazil. We performed elastography, ultrasound, and fine-needle aspiration biopsy in 32 patients between 6 and 18 years of age who had, in total, 38 thyroid nodules. RESULTS: The elastography findings correlated with the histopathological diagnosis in 78.5% of cases. In three patients, an unnecessary thyroidectomy could have been avoided if the elastography results had been prioritized. Only one malignant thyroid nodule was found to show high elasticity. CONCLUSION: Our results suggest that high elasticity of a nodule on elastography is associated with a low risk of thyroid cancer. If further confirmed in other studies, elastography may prove useful as a complementary test for screening thyroid nodules in children.

Keywords: Thyroid neoplasms; Child; Thyroid nodule/diagnostic imaging; Elasticity imaging techniques; Ultrasonography.

OBJECTIVE: To establish an overview of computed tomography (CT)-guided percutaneous nephrostomy performed at a referral center for cancer, addressing the characteristics of patients submitted to this intervention, as well as the indications for it, the technical specificities of it, and its main complications. MATERIALS AND METHODS: This was a retrospective study involving a review of the electronic medical records and images of patients submitted to CT-guided percutaneous nephrostomy at a referral center for cancer between 2014 and 2016. RESULTS: A total of 201 procedures were evaluated. In most cases, the obstruction was caused by a malignant neoplasm. Complications occurred in 9.5% of the cases, and an additional intervention was required (typically for catheter repositioning) in 36.6%. Post-procedure complications were not found to be significantly associated with the type of previous cancer treatment, the technique used, the caliber of the drain used in the procedure, or the degree of dilatation of the collection system prior to the procedure. CONCLUSION: In cancer patients, CT-guided percutaneous nephrostomy is an effective treatment, with success rates and complication rates similar to those reported in the general population.

Keywords: Nephrostomy, percutaneous/methods; Nephrostomy, percutaneous/adverse effects; Computed tomography.

OBJECTIVE: To evaluate progression rate of Bosniak category IIF complex renal cysts and the malignancy rate among surgically resected cysts. MATERIALS AND METHODS: We performed a database search for complex renal cysts classified as Bosniak category IIF on computed tomography or magnetic resonance imaging between January 2008 and April 2016. Follow-up examinations (computed tomography or magnetic resonance imaging) were used in order to evaluate progression (Bosniak category reclassification) and stability, the latter being defined as remaining stable for a minimum of six months. Pathology reports were used as the reference to assess the malignancy rate of surgically resected cysts. RESULTS: A total of 152 cysts in 143 patients were included in the final analysis. Seven cysts (4.6%) were reclassified on follow-up studies, and mean time to progression was 20 months (range, 1 month to 4 years). Three cysts were surgically resected. All three were diagnosed as low-grade malignant renal cell carcinomas (RCCs): one clear cell RCC and two papillary RCCs. The remaining 145 cysts remained unchanged after a mean follow-up period of 28 months (range, 6 to 118 months). CONCLUSION: The progression rate in Bosniak category IIF cysts was low. Even lesions that were upgraded on follow-up remained stable, indicating an indolent behavior. Our data support the idea of conservative management of Bosniak IIF renal cyst.

Keywords: Tomography, X-ray computed; Magnetic resonance imaging; Cysts/classification; Carcinoma, renal cell; Kidney/diagnostic imaging.

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.

OBJECTIVE: To evaluate the imaging findings of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and computed tomography (CT) in patients with additional primary tumors, correlating the results with those of the method used in order to elucidate the diagnosis and of the pathology reports. MATERIALS AND METHODS: We retrospectively analyzed the medical records, pathology reports and images of 11 patients who underwent CT, ¹⁸F-FDG PET/CT, or both. We included patients with at least two tumors, with confirmed distinct histopathological profiles, at different sites. Patients in whom there was no diagnostic confirmation were excluded, as were those in whom the additional lesion was suspected of being a metastasis of the first. RESULTS: New primary malignancies were identified in 11 patients, one new tumor being found in 10 and two new tumors being found in 1. The confirmed sites of the additional malignancies were the lung, kidney, prostate, jejunum, and breast. Single or multiple percutaneous biopsies were performed in 10 patients, and 1 patient underwent a surgical procedure for diagnostic and therapeutic purposes. The tumors were metachronous in 6 cases and synchronous in 5. CONCLUSION: CT and ¹⁸F-FDG PET-CT combined with multiple percutaneous biopsy could facilitate the diagnosis of additional lesions, thus optimizing the treatment and follow-up of the affected patients.

Keywords: Neoplasms, second primary/etiology; Biopsy, needle/methods; Positron-emission tomography/methods; Tomography, X-ray computed/methods; Fluorodeoxyglucose F18.

Central nervous system malformations constitute the second most common group of anomalies in fetuses. Such malformations have assumed clinical importance because of their association with high rates of perinatal morbidity and mortality. Therefore, it is extremely important to assess the fetal central nervous system during the prenatal period, in order to identify any changes in its development and thereby gain sufficient information to advise parents about pregnancy follow-up, options for fetal therapy, and the timing/type of delivery, as well as the postnatal treatment and prognosis. The objective of this review was to describe the ultrasonographic evaluation of the fetal central nervous system as per the guidelines of the International Society of Ultrasound in Obstetrics and Gynecology.

Keywords: Fetus; Central nervous system; Ultrasonography; Practice guidelines as topic.

The rupture of an abdominal aortic aneurysm (AAA) is considered a high-risk surgical emergency, given the catastrophic consequences and high mortality rate. The objective of this pictorial essay is to illustrate the radiological signs that indicate rupture or imminent rupture. To that end, we describe cases treated at our facility and present a brief review of the literature on the topic. The clinical diagnosis of imminent AAA rupture can be difficult, because patients are usually asymptomatic or have nonspecific pain complaints. In the subsequent follow-up, it is possible to identify radiological signs that indicate instability or rupture itself and thus change the prognosis. Computed tomography is the modality of choice for evaluating an AAA and abdominal pain in the emergency setting. It is therefore essential that the radiologist immediately identify the imaging findings that indicate AAA rupture or the imminent risk of such rupture.

Keywords: Aortic aneurysm, abdominal/complications; Aortic aneurysm, abdominal/mortality; Aortic rupture/diagnostic imaging; Abdominal pain/diagnostic imaging; Tomography, X-ray computed/methods.

The term avascular necrosis describes any one of a number of bone diseases that have a common mechanism: the death of bone components due to lack of blood supply. Avascular necrosis can occur in diverse parts of the skeleton, each location-specific form not only receiving a distinct designation but also presenting unique epidemiologic characteristics. However, the imaging findings are similar in all of the forms, which pass through well-described radiological phases, regardless of the site of involvement. Because avascular necrosis can cause considerable morbidity if not properly detected and managed, the radiologist plays a fundamental role. The present study provides a brief review of the main radiological aspects of the various forms of avascular necrosis, illustrated on the basis of a collection of cases from our institution.

Keywords: Osteonecrosis/diagnostic imaging; Radiography; Tomography, X-ray computed; Magnetic resonance imaging.

Coronary arteries originating from the contralateral (noncoronary) sinus and having an interarterial course, in which they run from the ascending aorta to the pulmonary trunk, is a potentially fatal anomaly. Computed tomography (CT) angiography facilitates the recognition and therapeutic planning of such anomalies because of its ability to acquire high-resolution images of the entire course of the coronary artery, as well as of the accompanying atherosclerotic involvement. The right coronary artery originating from the left coronary sinus is the most prevalent anomaly of this type and usually implies a better prognosis, the interarterial course being classified as "high" or "low", depending on whether it is above or below the level of the pulmonary valve, with consequent stratification of the risk and the treatment. However, it is known that there is a high risk of sudden death among patients with a left coronary artery of anomalous origin from the right sinus. In such cases, surgical treatment is recommended, regardless of whether there are symptoms or evidence of ischemia. Given the importance of those aspects, which can be identified on CT of the chest or CT angiography of the aorta, this pictorial essay aims to illustrate such anomalies to facilitate their recognition and description by radiologists who are not specialists in cardiac imaging.

Keywords: Coronary vessel anomalies/complications; Coronary vessel anomalies/diagnostic imaging; Aorta, thoracic/abnormalities; Aorta, thoracic/diagnostic imaging.