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

Prostate adenocarcinoma is the second tumor in incidence and mortality among malignant neoplasms in men. The differentiation between tumors confined to the organ and those with extraprostatic extension is critical for an appropriate therapeutic planning. Different studies have demonstrated that magnetic resonance imaging of the prostate with endorectal coil is useful in the local staging of these tumors. The present article presents information on the prostate gland anatomy, the tumor aspect at magnetic resonance imaging, specific signs of extracapsular extension and seminal vesicles invasion, protocol suggestions, general principles and relevance of proton spectroscopy, perfusion and diffusion imaging, role of magnetic resonance imaging in the postoperative and post-radiotherapy detection of local tumor recurrence, and also in the detection of lesions in patients with clinical/laboratory suspicion of prostate adenocarcinoma. Additionally, the present article describes differential diagnoses and limitations of the method.

Keywords: Prostate cancer, Adenocarcinoma, Magnetic resonance imaging, Cancer staging

OBJECTIVE: To assess the rate of geographic miss on conventional radiotherapy planning of patients with cervical cancer, using magnetic resonance imaging. MATERIALS AND METHODS: Thirty-two patients with squamous cell carcinoma of the uterine cervix were studied. Magnetic resonance imaging of the pelvis was performed after clinical staging. Magnetic resonance imaging findings were compared with the classic fields described for the "box" technique. Target volume within less than 1 cm margins of the fields' limits was considered as geographic miss. RESULTS: Classical radiation field limits were inadequate in 24 cases (75%), all in the anterior (46%) or posterior (40%) border of the lateral fields. CONCLUSION: Magnetic resonance detected a high probability of geographic miss on conventional radiotherapy planning in this population, both in initial and advanced stages of the disease.

Keywords: Uterine cervix cancer, Radiotherapy, Magnetic resonance imaging

Acute pancreatitis is an inflammatory condition caused by intracellular activation and extravasation of inappropriate proteolytic enzymes determining destruction of pancreatic parenchyma and peripancreatic tissues. This is a fairly common clinical condition with two main presentations, namely, endematous pancreatitis - a less severe presentation -, and necrotizing pancreatitis - the most severe presentation that affects a significant part of patients. The radiological evaluation, particularly by computed tomography, plays a fundamental role in the definition of the management of severe cases, especially regarding the characterization of local complications with implications in the prognosis and in the definition of the therapeutic approach. New concepts include the subdivision of necrotizing pancreatitis into the following presentations: pancreatic parenchymal necrosis with concomitant peripancreatic tissue necrosis, and necrosis restricted to peripancreatic tissues. Moreover, there was a systematization of the terms acute peripancreatic fluid collection, pseudocyst, post-necrotic pancreatic/peripancreatic fluid collections and walled-off pancreatic necrosis. The knowledge about such terms is extremely relevant to standardize the terminology utilized by specialists involved in the diagnosis and treatment of these patients.

Keywords: Pancreatitis; Pseudocyst; Walled-off pancreatic necrosis.

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.

Acute penile conditions, which typically have a traumatic, vascular, or infectious etiology, are rather uncommon and often require prompt medical evaluation. Penile emergencies can be treated conservatively or surgically, and their management often relies on the results of imaging examinations. Because of its high spatial resolution and wide availability, as well as the fact that it does not involve the use of ionizing radiation, ultrasound is the imaging modality of choice in the initial evaluation of penile emergencies. Inconclusive cases can be further evaluated with magnetic resonance imaging. The main purpose of this pictorial essay is to review the main penile emergencies, by presenting illustrative cases, focusing on radiologic findings, and discussing the roles played by the various imaging methods.

Keywords: Penile diseases/pathology; Penile diseases/etiology; Emergencies; Emergency medicine; Urology; Radiology.

OBJECTIVE: To evaluate the correlation of morphological criteria of the cecal appendix using computed tomography (CT) and the possible risk of developing acute appendicitis. MATERIALS AND METHODS: Cases were defined as patients with surgically confirmed acute appendicitis who had undergone CT at least twice: at diagnosis and at least one month prior. Controls were defined as emergency patients with abdominal pain who had undergone abdominal CT that excluded acute appendicitis and had also undergone CT at least one month before. RESULTS: 100 cases and 100 controls were selected for inclusion in the final analysis. Comparisons between the cases and controls revealed the following: mean transverse diameter of 0.6 cm (range, 0.4–1.0 cm) versus 0.6 cm (range, 0.6–0.8 cm; p = 0.37); mean length of 6.6 cm (range, 3.5–9.7 cm) versus 6.6 cm (range, 4.5–8.3 cm; p = 0.87); mean angle of 100º (range, 23–178º) versus 86º (range, 43–160º; p = 0.01); vertical descending orientation in 56% versus 45% (p = 0.2); absence of gas in 69% versus 77% (p = 0.34); and presence of an appendicolith in 17% versus 8% (p = 0.08). CONCLUSION: Hypothetical risk factors for obstruction of the vermiform appendix detected on CT were not associated with acute appendicitis. That suggests that factors other than those related to mechanical obstruction are implicated in the pathogenesis of acute appendicitis.

Keywords: Appendicitis; Appendix; Multidetector computed tomography; Emergency medicine.

More than half of patients over 50 years of age have had at least one focal renal lesion detected as an incidental finding during an ultrasound, computed tomography, or magnetic resonance imaging examination. Although the majority of such lesions can be easily detected and correctly characterized, misdiagnoses may occur and are often related to methodological limitations, inappropriate imaging protocols, or misinterpretation. This pictorial essay provides recommendations on how to recognize benign and malignant renal processes that can be potentially missed or mischaracterized in imaging studies.

Keywords: Kidney neoplasms/diagnostic imaging; Magnetic resonance imaging; Ultrasonography; Computed tomography.

OBJECTIVE: To assess the practical aspects of the use of various gadolinium-based contrast agents (GBCAs) by radiologists. MATERIALS AND METHODS: Ten experienced radiologists from different regions of Brazil participated in a Delphi panel querying their use of various GBCAs, including linear and macrocyclic classes (1.0 and 0.5 M), in terms of the choice of agent, volume and dosage of the agents, and associated safety concerns. RESULTS: The response rate was 100% for all questions. GBCAs are safe in terms of acute adverse reactions, and nephrogenic systemic fibrosis is rare. The deposition of gadolinium in the brain and other tissues is a concern among the experts. Macrocyclic agents are preferable to linear agents; an injection volume below 0.1 mL/kg of a 1.0 M agent could result in good-quality images with additional long-term safety, but there is no published evidence to support this recommendation. The majority of experts preferred not to administer GBCAs to pregnant patients. CONCLUSION: When choosing a GBCA, it is important to consider the characteristics of the gadolinium deposition in patient tissues and minimize potential risks. Furthermore, medical education programs are needed to increase the awareness of the potential risks of gadolinium deposition and thus avoid instances of overexposure to the contrast agent.

Keywords: Contrast media; Gadolinium; Magnetic resonance imaging; Gadolinium-based contrast agents; Safety.