Studies of iodixanol in the rabbit lung and peritoneum.

OBJECTIVE: To evaluate a new water-soluble contrast agent, iodixanol. The study evaluates absorption from the peritoneal cavity and toxicity in the lung. MATERIALS AND METHODS: Thirty New Zealand white rabbits were given the study agent and comparative agents into an endotracheal tube. Serial chest radiographs were evaluated for development of pulmonary edema. All lungs were evaluated histopathologically for toxic inflammatory response. Fifteen different rabbits were given intraperitoneal injection of the study and comparative contrast agents. Serial abdomen radiographs, taken up to 24 h after injection, were evaluated for contrast absorption from the peritoneal cavity. RESULTS: Evaluation of indicators of pulmonary edema demonstrated that iodixanol caused the same or less pulmonary edema than comparative agents. Histopathologic analysis showed that iodixanol caused less macrophage response than saline (P = 0.010), the same lymphocyte infiltration as saline (P = 0.472), the same neutrophil response as saline (P = 0.297), and the same vasculitic reaction as saline (P = 0.128). Compared to iohexol 270, iodixanol caused the same macrophage infiltrate (P = 0.924), the same lymphocyte infiltration (P = 0.523), more neutrophil reaction (P = 0.007), and less vasculitic reaction (P = 0.042). Iodixanol was rapidly absorbed from the peritoneal cavity. CONCLUSION: Iodixanol is a new contrast agent that is isotonic at all clinically useful iodine concentrations. It appears safe in the lung and is absorbed from the peritoneal cavity.

Visual presentation of the staging of pediatric solid tumors.

Staging systems are used in staging most pediatric solid tumors outside the central nervous system. Common solid, nonneurologic pediatric tumors include liver tumors, Hodgkin disease, non-Hodgkin lymphoma, Wilms tumor, rhabdomyosarcoma, neuroblastoma, Ewing sarcoma, and osteosarcoma. Traditional staging of pediatric tumors depends on the anatomic distribution of the malignant disease. Almost all staging systems are based on the spread of the local primary tumor, metastasis to regional lymph nodes, and distant blood-borne metastatic spread. There is some variability as to how tumor spread is assessed. Such assessment may be performed before or after surgery. There are many potential problems with tumor staging systems. The systems vary in complexity and clinical usefulness, and there is some variation in the criteria used in the different systems. It is important for radiologists to have a sound working knowledge of staging systems to facilitate accurate staging. Imaging is an important aspect of every staging system.

Renal pseudotumor due to aberrant renal capsular artery supplying normal spleen.

A renal pseudotumor caused by a small portion of normal spleen receiving blood supply from a renal capsular artery is described. CT with nonselective enhancement and liver/spleen scan may fail to delineate this previously unreported finding. CT angiography, however, can establish the diagnosis. The consideration of this situation in the differential diagnosis may help avoid costly additional workup.