Contrast material for combined abdominal and pelvic CT: can cost be reduced by increasing the concentration and decreasing the volume?

OBJECTIVE: The purpose of this study was to determine if enhancement provided by a smaller volume of a more concentrated nonionic contrast agent is equivalent to that provided by a larger volume of a less concentrated nonionic agent on dynamic, incremental abdominal and pelvic CT. SUBJECTS AND METHODS: During a 4-month period, 168 patients undergoing dynamic incremental abdominal and pelvic CT received 150 ml iopamidol-300 (45 g iodine). During the following 4 months, 119 patients received 125 ml ioversol-320 (40 g iodine). The same automated injector and scanning parameters were used for both groups. Absolute enhancement of the liver at three levels and of abdominal and pelvic vessels was calculated and analyzed by using Student's t-test. RESULTS: Arterial and venous enhancement in the upper part of the abdomen, at the level of the iliac crest, or in the pelvis was not significantly different with the two contrast agents. Both ioversol and iopamidol provided the same mean enhancement of the hepatic parenchyma at the level of the hepatic veins (45 H) and at the level of the portal vein (49 H). At the level of the gallbladder fossa, enhancement of liver parenchyma with the two contrast agents was significantly different (p = .04): mean enhancement was 45 H for iopamidol and 42 H for ioversol. A retrospective analysis of the liver enhancement profiles from 50 randomly selected patients from each group showed no significant difference in parenchymal enhancement. CONCLUSION: For dynamic abdominal and pelvic CT, no statistically significant difference was found between the mean enhancement of the liver and abdominal vessels after administration of 125 ml of ioversol-320 and that after administration of 150 ml of iopamidol-300. Therefore, 125 ml of ioversol-320 can be used instead of 150 ml of iopamidol-300 without compromising image quality. At current prices, this will result in savings of approximately 18% per patient.

Comparison of the costs and morbidity of percutaneous and open flank procedures.

A series of 47 percutaneous procedures for renal calculi was matched by description of calculi and previous flank exploration to 47 open flank procedures for comparison of relative morbidity and cost-efficiency. A retrospective analysis of paired data demonstrated that patients undergoing percutaneous procedures experienced significantly decreased duration of anesthesia, number of transfusions, postoperative disability, and duration and cost of hospitalization. These findings support the cost-effectiveness of the percutaneous approach to removal of renal calculi.

Abdominal computed tomography in small cell lung cancer: assessment of extent of disease and response to therapy.

Abdominal computed tomography (CT) was performed as part of the initial staging evaluation in 77 patients with small cell carcinoma (SCC) of the lung. CT scans revealed mass lesions in 26 patients (34%). Abnormalities were confined to the liver in 15 patients and to retroperitoneal structures (lymph nodes, adrenal glands, psoas muscle region masses) in eight, and occurred in both areas in three. However, only three of 29 patients otherwise staged as having limited disease (confined to one hemithorax and regional nodes) had evidence of abdominal metastases on CT scan. Most (23/26) positive studies were in patients already known to have more extensive tumor dissemination. In 71 patients with pathologic confirmation of liver status, CT had a sensitivity of 63%, specificity of 91%, and overall accuracy of 85% in assessing the liver. Comparison of radionuclide liver scan findings with hepatic biopsies gave similar results. During therapy, 65 follow-up CT scans were obtained in 46 patients. Scan abnormalities improved or disappeared in 11/12 cases with tumor response documented in other ways, appeared or worsened in 5/13 cases of tumor progression that was diagnosed by other tests, and only rarely (2/65 scans) improved at the time of documented tumor progression, or vice versa. In only three patients, however, did CT scan provide the sole site of evaluable disease during treatment or detect either the only area of residual disease in a patient in otherwise complete remission or the initial evidence of tumor progression. Although abdominal CT scans in SCC can demonstrate metastatic dissemination not evaluable by other means, they provide relatively little therapeutically relevant information beyond that obtained with standard staging procedures.

Intraperitoneal contrast infusion for assessment of intraperitoneal fluid dynamics.

For patients undergoing intraperitoneal ("belly bath") chemotherapy, it is useful to verify the distribution of infusion fluid. For this reason, 10 patients were examined by computed tomography (CT) after intraperitoneal instillation of dialysate mixed with water soluble contrast material. The extent of intraperitoneal distribution was assessed, and in two patients filling defects, presumably representing tumor, were identified.