Hepatocellular carcinoma (HCC) is a global health problem, with the burden of disease expected to increase in the coming years. Patients who are at increased risk for developing HCC undergo routine imaging surveillance, and once a focal abnormality is detected, evaluation with multiphasic contrast material-enhanced computed tomography or magnetic resonance imaging is necessary for diagnosis and staging. Currently, findings at liver imaging are inconsistently interpreted and reported by most radiologists. The Liver Imaging-Reporting and Data System (LI-RADS) is an initiative supported by the American College of Radiology that aims to reduce variability in lesion interpretation by standardizing report content and structure; improving communication with clinicians; and facilitating decision making (eg, for transplantation, ablative therapy, or chemotherapy), outcome monitoring, performance auditing, quality assurance, and research. Five categories that follow the diagnostic thought process are used to stratify individual observations according to the level of concern for HCC, with the most worrisome imaging features including a masslike configuration, arterial phase hyperenhancement, portal venous phase or later phase hypoenhancement, an increase of 10 mm or more in diameter within 1 year, and tumor within the lumen of a vein. LI-RADS continues to evolve and is expected to integrate a series of improvements in future versions that will positively affect the care of at-risk patients.

Right lower quadrant abdominal pain is one of the most common causes of a patient visit to the emergency department. Although appendicitis is the most common condition requiring surgery in patients with abdominal pain, right lower quadrant pain can be indicative of a vast list of differential diagnoses and is thus a challenge for clinicians. Other causes of right lower quadrant pain beyond appendicitis include inflammatory and infectious conditions involving the ileocecal region; diverticulitis; malignancies; conditions affecting the epiploic appendages, omentum, and mesentery; and miscellaneous conditions. Multidetector computed tomography (CT) has emerged as the modality of choice for evaluation of patients with several acute traumatic and nontraumatic conditions causing right lower quadrant pain. Multidetector CT is an extremely useful noninvasive method for diagnosis and management of not only the most common causes such as appendicitis but also less common conditions.

The kidneys and perinephric tissues can be affected by a variety of hematologic disorders, which usually occur in the setting of multisystem involvement. In many of these disorders, imaging is used to evaluate the extent of disease, guide biopsy, and/or monitor disease activity and patient response to therapy. Lymphoma, leukemia, and multiple myeloma commonly manifest as multiple parenchymal or perinephric lesions. Erdheim-Chester disease and Rosai-Dorfman disease, rare forms of multisystemic histiocytosis, are often identified as perinephric and periureteral masses. Renal abnormalities depicted at imaging in patients with sickle cell disease include renal enlargement, papillary necrosis, and renal medullary carcinoma. Sickle cell disease, along with other causes of intravascular hemolysis, can also lead to hemosiderosis of the renal cortex. Thrombosis of renal veins is sometimes seen in patients with coagulation disorders but more often occurs in association with certain malignancies and nephrotic syndrome. Immunoglobulin G4-related sclerosing disease is another multisystem process that often produces focal renal lesions, seen along with involvement of more characteristic organs such as the pancreas. Perinephric lesions with calcifications should raise the possibility of secondary amyloidosis, especially in patients with a history of lymphoma and multiple myeloma. Although the imaging patterns of renal and perinephric involvement are usually not specific for a single entity, and the same entity can manifest with different or overlapping patterns, familiarity with these patterns and key clinical and histopathologic features may help to narrow the differential diagnosis and determine the next step of care. (©)RSNA, 2016.

Although most rectal masses are histologically characterized as adenocarcinomas, the rectum and perirectal region can be affected by a wide variety of tumors and tumor-like conditions that can mimic the symptoms caused by rectal adenocarcinoma, including mucosal or submucosal rectal tumors such as lymphoma, gastrointestinal stromal tumor, leiomyosarcoma, neuroendocrine tumor, hemangioma, and melanoma, as well as tumors of the perirectal region such as developmental cyst, neurogenic tumor, osseous tumor, and other miscellaneous conditions. As a group, tumors of the rectum are considerably different from the group of tumors that arise in the perirectal region: they are most often neoplastic, symptomatic, and malignant, whereas tumors arising in the perirectal region are most commonly congenital, asymptomatic, and benign. Proctoscopy with biopsy is the most important method for the diagnosis of rectal tumors, but this procedure cannot determine the precise intramural extension of a rectal tumor and cannot accurately distinguish submucosal and intramural tumors from extramural tumors. Cross-sectional imaging, especially transrectal ultrasound and magnetic resonance imaging, allows evaluation of the entire bowel wall thickness and the perirectal tissues, helping further characterize these tumors. Recognition of the existence of these masses and their key clinical and imaging features is crucial for clinicians to accurately diagnose and appropriately manage these conditions.

OBJETIVO: Avaliar a acurácia da tomografia de alta resolução (TCAR) do tórax em relação à radiografia simples (RX) do tórax no diagnóstico de doença intersticial pulmonar relacionada à esclerose sistêmica (ES). MATERIAIS E MÉTODOS: Foram realizados TCAR e RX de tórax em póstero-anterior e perfil em 34 pacientes com diagnóstico de ES, segundo critérios do Colégio Americano de Reumatologia, e feita comparação entre as prevalências dos achados radiológicos sugestivos de doença intersticial pulmonar encontradas com estes dois métodos de imagem. RESULTADOS: Foram observadas alterações em 31 (91%) das TCAR, enquanto 16 (47%) dos RX de tórax se apresentavam alterados. Os achados mais freqüentes à TCAR foram: linhas septais (74%), faveolamento (56%) e bandas parenquimatosas (26%), localizados predominantemente nas bases pulmonares. Os RX de tórax demonstraram áreas de infiltrado reticular em 32% dos casos e distorção parenquimatosa em 12% dos pacientes. Em 18 (53%) pacientes com RX de tórax normal a TCAR revelou espessamento septal em 55%, vidro fosco em 44%, faveolamento em 38,5% e cistos em 33%. CONCLUSÃO: A TCAR é mais sensível que o RX de tórax para a investigação de envolvimento intersticial pulmonar inicial em pacientes com ES, justificando, em casos incipientes, tratamento com terapia imunossupressora.