Comparison of single- and triple-dose contrast material in the MR screening of brain metastases.

PURPOSE: Although studies obtained with triple-dose contrast administration can show more brain metastases than those obtained with single-dose contrast material in patients with multiple metastases, such studies are costly and of limited clinical benefit. Since most patients who undergo screening have negative findings or a single metastasis, this study was performed to compare the clinical utility of single-dose versus triple-dose contrast administration in this large group of patients who could benefit from the possible increased sensitivity in lesion detection. METHODS: Ninety-two consecutive patients with negative or equivocal findings or a solitary metastasis on single-dose contrast-enhanced MR images underwent triple-dose studies. Findings were compared with a standard of reference composed of panel review and long-term follow-up. Further analysis was performed by comparing results with those obtained by two blinded readers. RESULTS: In all 70 negative single-dose studies, the triple-dose studies depicted no additional metastases in terms of the standard of reference. No statistically significant difference was seen between the results of the single- and triple-dose studies. For 10 equivocal single-dose studies, the triple-dose study helped clarify the presence or absence of metastases in 50% of the cases. In 12 patients with a solitary metastasis seen on the single-dose study, the triple-dose study depicted additional metastases in 25% of the cases. In the results of one of the two blinded readers, use of triple-dose contrast led to a statistical difference by decreasing the number of equivocal readings but at the expense of increasing the number of false-positive readings. CONCLUSION: Routine triple-dose contrast administration in all cases of suspected brain metastasis is not helpful. On the basis of our investigation, we conclude that the use of triple-dose contrast material is beneficial in selected cases with equivocal findings or solitary metastasis, although with the disadvantage of increasing the number of false-positive results.

Translumbar arch aortography: a retrospective controlled study of usefulness, technique, and safety.

Subclavian and axillary artery stenoses may lead to axillofemoral bypass graft failure. These arteries were assessed preoperatively with arch aortography performed after conventional high translumbar peripheral aortography by exchanging the initial 16-gauge sheath for a 5-F pigtail catheter. Thirty-two diagnostic translumbar runoff and arch (TLR-arch) aortograms were obtained in 30 patients with advanced lower extremity ischemia. In six patients (20%), the results of the arch study influenced the choice of an inflow site. These patients were compared with 70 control subjects who underwent conventional translumbar aortography without arch studies. In the TLR-arch group, two major complications occurred in one patient, while in the control group 11 major complications occurred in 10 patients. One retroperitoneal hematoma occurred in the TLR-arch group; two occurred in the control group. The mean change in hematocrit for the TLR-arch group was -3.81% (-0.0381), and for the control group it was -4.17% (-0.0417). This difference was not statistically significant. Arch aortography is a valuable adjunct to the translumbar aortofemoral study. It can be simply performed without increasing the morbidity of the peripheral study.