CT evaluation of mediastinal masses in children: spectrum of disease with pathologic correlation.

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.

Pancreatic disease in children and young adults: evaluation with CT.

In children with pancreatic disease, computed tomography (CT) has a primary role in the evaluation of pancreatitis, trauma, and malignancy. At CT, pancreatic abnormalities may manifest as pancreatic enlargement (tumor, acute pancreatitis), pancreatic atrophy (cystic fibrosis, chronic pancreatitis), cystic lesions (pseudocysts, congenital simple cysts, autosomal dominant polycystic kidney disease, von Hippel-Lindau disease, cystic fibrosis, cystic neoplasms), or fatty replacement (cystic fibrosis, Shwachman-Diamond syndrome, history of steroid therapy, Cushing syndrome, Johanson-Blizzard syndrome, obesity). CT is the best modality for evaluation of pancreatitis, allowing detection of pancreatic abnormalities as well as abnormal extrapancreatic fluid collections. In children who have undergone blunt abdominal trauma, CT has been shown to be the best initial imaging study, being more sensitive than ultrasound for detection of pancreatic injury. In neoplastic conditions, CT demonstrates the extent of disease, enables characterization of the tissue components of the tumor, and allows accurate posttreatment follow-up. Although the various diseases of the pancreas may have overlapping appearances at CT, the correct diagnosis can often be made on the basis of the CT findings in combination with the clinical history, laboratory data, and the patient's age.

Posterior superior temporal gyrus in schizophrenia: grey matter changes and clinical correlates.

We report an MRI morphometric study of the posterior segment of the superior temporal gyrus (STG) in twenty young male schizophrenics and their individually matched normal controls. In particular the more posterior segment of STG was examined, since it has been identified as the approximate site of Wernicke's language area and is a marker for the planum temporale, a region believed to be abnormal in schizophrenia. Total volumes and grey and white matter volumes were measured in middle and posterior STG in each hemisphere. STG grey matter volumes and percentages were significantly reduced bilaterally in both regions in schizophrenic subjects. No significant differences between patients and controls were noted in STG white matter volumes. A significant correlation was detected between delusion scores in schizophrenics and the total volume of the left dominant posterior STG. Replicating the findings of a recent study (Shenton et al., 1992), we found an inverse correlation between thought disorder scores and grey matter reduction in the left posterior STG in schizophrenia.

Reversal of asymmetry of the planum temporale in schizophrenia.

OBJECTIVE: The planum temporale is intimately involved in the generation and understanding of language and has been suggested to be a key area affected in schizophrenia. To explore temporal lobe abnormalities in schizophrenia, the authors measured the planum temporale, a normally asymmetric area lying on the superior part of the temporal lobe, in schizophrenic patients. METHOD: High-resolution magnetic resonance imaging (MRI) scans were obtained for 14 right-handed schizophrenic patients and 14 healthy comparison subjects individually matched for age, sex, handedness, race, and parental socioeconomic status. The surface area of the planum temporale was measured by using MRI reconstruction techniques. RESULTS: There was striking reversal of the normal asymmetry (left larger than right) in planum temporale surface area in 13 of the schizophrenic patients but in only two of the comparison subjects. However, Heschl's gyrus (primary sensory cortex), which served as an anatomically contiguous nonheteromodal cortical comparison region, showed no difference between the left and right sides in either group. Severity of thought disorder in the patients was related to asymmetry. CONCLUSIONS: This is a clear demonstration of a reversal of expected symmetry in the brains of right-handed schizophrenic patients, which involves a region of key importance in normal human behavior. The nature of the abnormality strongly suggests that schizophrenia is a neurodevelopmental disorder.