Critical reviews in diagnostic imaging最新文献

In the U.S., acute pancreatitis is usually caused by excessive consumption of ethanol or by biliary stone disease. Major pathologic finding and complications include fluid collections within the organ or the adjacent peripancreatic tissues, pseudocysts, pancreatic necrosis, pseudoaneurysm, and abscess formation. Radiologic imaging, including endoscopic retrograde cholangiopancreatography (ERCP), sonography, and computed tomography (CT), are important in the evaluation of acute pancreatitis and its complications. CT in particular also aids in grading the severity of acute pancreatitis and in predicting complications and mortality; however, CT correlation with Ranson's clinical prognostic factors or with other classification systems is less clear. The imaging and therapeutic aspects of acute pancreatitis are discussed and illustrated and prognostic factors are correlated.

The mediastinum is the site of a variety of benign and malignant pathological processes in children. While the chest radiograph may be the initial imaging study to suggest an abnormality, spiral or helical CT provides detailed depiction of anatomic relationships and characteristics of the mass, and may increase the likelihood of a successful examination because of shorter scan times. This article will emphasize the important CT features in the evaluation of common and uncommon mediastinal masses in children. Pathologic correlation is presented for greater understanding. In many clinical settings, CT features such as attenuation, enhancement, calcification, anatomic relationships and extent of disease may suggest a specific diagnosis for a mediastinal mass in a child.

The thoracic manifestations of AIDS have undergone a gradual metamorphosis, partly due to more awareness about the disease leading to earlier diagnoses and partly due to the fact that research has produced more effective prophylaxis as well as treatment for these patients. Many patients now demonstrate partial or complete clinical response which prolongs the length and quality of life of individuals positive for the Human Immunodeficiency Virus (HIV+). Also, with the large number of infected individuals coming to medical attention, and the years of experience in diagnosing and treating these AIDS patients, we now recognize not only the usual but also less usual manifestations of thoracic illnesses in AIDS, including infections, non-infectious diseases such as HIV associated Lymphocytic Interstitial Pneumonia and the neoplasms associated with AIDS. A section will be devoted to HIV infection in children. We will finish the article with a discussion of the current role of Nuclear Medicine in the diagnosis of HIV associated thoracic diseases. These topics are the subject of this article.

1. High-resolution MRCP is a noninvasive imaging modality for depicting the pancreatobiliary tree. The imaging quality of high-resolution MRCP is satisfactory. MRCP can demonstrate dilation, stenosis, and intraductal filling defects of both the biliary tract and the pancreatic duct, which meets the clinical demand for pancreatobiliary imaging. 2. MRCP was successful in almost all the patients. However, the causes of MRCP failure were patient motion, irregular respiratory rhythm, severe pneumobilia, and massive ascitic fluid. 3. When only MIP reconstructed images were used for interpretation, small intraductal filling defects such as a gallstone can be missed. In combination with coronal source images, the ability to detect intraductal stones can be increased. 4. Ferrite ammonium citrate (FAC) is useful in suppressing the background signal intensity of gastrointestinal contents so that the ducts can be clearly visualized. The other technique for decreasing the background signal intensity is target MIP postprocessing, which works well for better visualization of the ducts. 5. The degree of ductal narrowing tends to be overestimated with MRCP because of MIP reconstruction artifact and lower spatial resolution of MRCP than ERCP. 6. MRCP has a diagnostic pitfall of a pseudostenosis of extrahepatic ducts, which may lead to a false-positive diagnosis of ductal narrowing. This pitfall may be caused not only by MIP postprocessing artifacts but by gas, surgical metal, and vascular compression of right hepatic artery. There is another diagnostic pitfall that it is difficult to differentiate intraductal mucin from pancreatic fluid in dilate pancreatic ducts, although ERCP identifies mucin as intraductal filling defects.

MR imaging has become a valuable tool in the diagnosis of pathologic conditions of the foot. The direct multiplanar imaging capability, superior soft tissue contrast discrimination, and spatial resolution afforded by MR are advantages over other imaging modalities. The complex anatomy and spectrum of pathology in this region present a significant challenge to the radiologist. Familiarity with the anatomy, various clinical conditions, and their appearance on MR imaging is essential for accurate diagnosis. In this article, a limited review of the anatomy of the foot is presented together with a more in-depth discussion and illustration of a wide variety of pathologic conditions of the foot. Emphasis is placed on those conditions that are relatively unique to the foot.