Magnetic resonance imaging is an important tool for the detection and characterization of adrenal tumors. The knowledge about the different presentations of primary and secondary adrenal tumors at magnetic resonance imaging and their correlation with histological data are essential for the establishment of a correct diagnosis. The present study reviews magnetic resonance imaging aspects which may narrow the differential diagnosis of adrenal tumors, emphasizing the histological correlation of the most frequent ones.

Keywords: Magnetic resonance imaging, Adrenal glands, Retroperitoneal neoplasms, Urogenital neoplasms, Imaging diagnosis

Magnetic resonance imaging is a method with high contrast resolution widely used in the assessment of pelvic gynecological diseases. However, the potential of such method to diagnose vaginal lesions is still underestimated, probably due to the scarce literature approaching the theme, the poor familiarity of radiologists with vaginal diseases, some of them relatively rare, and to the many peculiarities involved in the assessment of the vagina. Thus, the authors illustrate the role of magnetic resonance imaging in the evaluation of vaginal diseases and the main relevant findings to be considered in the clinical decision making process.

Keywords: Magnetic resonance imaging; Vagina; Tumors; Congenital malformations.

A large number of gadolinium chelates have recently been tested in clinical trials. Some of those have already been approved for clinical use in the United States and Europe. Thus, new diagnostic perspectives have been incorporated into magnetic resonance imaging studies. Among such gadolinium chelates are hepatobiliary-specific contrast agents (HSCAs), which, due to their property of being selectively taken up by hepatocytes and excreted by the biliary ducts, have been widely used for the detection and characterization of focal hepatic lesions. In comparison with conventional magnetic resonance cholangiography (MRC), HSCA-enhanced MRC provides additional information, with higher spatial resolution and better anatomic evaluation of a non-dilated biliary tree. A thorough anatomic assessment of the biliary tree is crucial in various hepatic surgical procedures, such as complex resection in patients with colorectal cancer and living-donor liver transplantation. However, the use of HSCA-enhanced MRC is still limited, because of a lack of data in the literature and the poor familiarity of radiologists regarding its main indications. This pictorial essay aims to demonstrate the use of HSCA-enhanced MRC, with particular emphasis on anatomical analysis of the biliary tree, clinical applications, and the most important imaging findings.

Keywords: Biliary tree; Magnetic resonance imaging; Hepatobiliary-specific contrast agents.

Primary retroperitoneal masses constitute a heterogeneous group of uncommon lesions and represent a challenge due to overlapping imaging findings. Most are malignant lesions. Although they are more prevalent in adults, they can occur at any age. Such lesions are classified as primary when they do not originate from a specific retroperitoneal organ and are divided, according to the image findings, into two major groups: solid and cystic. The clinical findings are nonspecific and vary depending on the location of the lesion in relation to adjacent structures, as well as on its behavior. The main imaging methods used for staging and surgical planning, as well as for selecting the biopsy site and guiding the biopsy procedure, are computed tomography and magnetic resonance imaging. In most cases, the treatment is challenging, because of the size of the lesions, vascular involvement, or involvement of adjacent organs. In this article, we present a review of the retroperitoneal anatomy and a practical approach to the main imaging features to be evaluated, with a view to the differential diagnosis, which can guide the clinical management.

Keywords: Retroperitoneal space/anatomy & histology; Retroperitoneal neoplasms/diagnosis; Tomography, X-ray computed; Magnetic resonance imaging.

OBJECTIVE: To determine whether ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography performed immediately after percutaneous ablation (_iPA¹⁸F-FDG PET/CT) is useful in evaluating the outcomes of the procedure. MATERIALS AND METHODS: This was a retrospective study of 20 patients (13 males, 7 females; mean age, 65.8 ± 12.1 years) submitted to percutaneous ablation of metastases. All of the lesions treated had shown focal uptake on a ¹⁸F-FDG PET/CT scan obtained at baseline. The primary tumors were mainly colorectal cancer (in 45%) or lung cancer (in 40%). _iPA¹⁸F-FDG PET/CT was performed to identify any residual viable tumor cells. The treatment was considered a success (no viable tumor cells present) if no uptake of ¹⁸F-FDG was noted on the _iPA¹⁸F-FDG PET/CT scan. RESULTS: Twenty-six lesions were submitted to percutaneous ablation with either cryoablation (n = 7) or radiofrequency ablation (n = 19). The mean lesion diameter was 2.52 ± 1.49 cm. For the detection of viable tumor cells, _iPA¹⁸F-FDG PET/CT had a sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 66.7%, 95%, 88.5%, 80%, and 90.5%, respectively. There was a significant correlation between the _iPA¹⁸F-FDG PET/CT findings and the results of the follow-up studies (kappa = 0.66; p < 0.01). CONCLUSION: _iPA¹⁸F-FDG PET/CT studies appear to constitute a useful means of evaluating the outcomes of percutaneous ablation. By detecting residual viable tumor cells, this strategy might allow early re-intervention, thus reducing morbidity. Studies involving larger numbers of patients are needed in order to confirm our findings.

Keywords: Fluorodeoxyglucose F18; Positron-emission tomography/methods; Tomography, X-ray computed/methods; Ablation techniques; Cryosurgery/methods; Radiofrequency ablation.