PURPOSE: To prospectively compare the diagnostic accuracy of CO2 and gadolinium to iodinated contrast material for inferior vena cavography before inferior vena cava (IVC) filter placement. MATERIALS AND METHODS: Forty patients underwent injection of iodinated contrast material, CO2, and gadolinium. Iodinated contrast material was used as the standard. Caval diameter was determined with calibrated software. Three readers blinded to contrast agent used measured the distance from the superior image border to the inferior margin of the renal veins and from the inferior image border to the iliac bifurcation. The measurements with CO2 and gadolinium were compared to those with iodinated contrast material to obtain the interobserver and intraobserver variability. The presence or absence of caval thrombus and variant anatomy was noted. The same readers reexamined 12 studies in a separate session to determine intraobserver variability and correlation. RESULTS: Caval diameter differed by 0.4 mm or less for all three agents. Measurements with all agents were within 2 mm of each other for all patients. Gadolinium and CO2 were not significantly different from one another in measuring caval diameter. At the initial reading, compared with iodinated contrast material, gadolinium had greater mean interobserver error in measuring the distance to the iliac bifurcation and both renal veins (range, 1.6-1.8 mm) than CO2 (range, 0.2-1.4 mm). This finding, although statistically significant for gadolinium (P < .05), was of doubtful clinical relevance. Interobserver correlation was significantly worse for CO2 at the levels of the iliac bifurcation (P = .02) and right renal vein (P = .008). Interobserver correlation for gadolinium was similar to that for iodinated contrast material at all levels. At repeat reading, there was significantly inferior intraobserver correlation with use of CO2 for both renal veins (P < .05) compared to iodinated contrast material and for the left renal vein (P < .05) compared to gadolinium. Gadolinium identified three of three renal vein anomalies identified with iodinated contrast material whereas CO2 localized one of three. CONCLUSION: CO2 and gadolinium had limitations when compared with iodinated contrast material. Gadolinium provided superior consistency in identifying relevant landmarks for filter placement. CO2 demonstrated significantly greater mean correlative error than gadolinium at initial and repeat readings.
|Number of pages||6|
|Journal||Journal of Vascular and Interventional Radiology|
|State||Published - Aug 1 2003|