PURPOSE: To prospectively evaluate the safety and effectiveness of gadolinium-enhanced multi-detector row spiral computed tomographic (CT) angiography of the pulmonary circulation by using two gadolinium doses in patients with contraindications to iodinated contrast agents.
MATERIALS AND METHODS: Study was approved by the Ethics Committee, and written informed consent was obtained. Thirty-seven patients (20 men, 17 women) with contraindications to iodinated contrast agents (allergic reactions, n - 27; impaired renal function, n = 10) underwent CT angiography of the pulmonary circulation in search of acute pulmonary embolism (n = 28) or for management of tumoral disease (n = 9). CT angiography was performed (a) with four-detector row (n = 19) or 16-detector row (r? = 18) scanners; (b) at randomly assigned gadolinium doses of either 0.3 mmol per kilogram of body weight (n = 19) or 0.4 mmol/kg (n = 18); and (c) with a systematic evaluation of clinical and biologic tolerance of gadolinium. Comparison of percentages between group 1 and group 2 scans was performed with the x2 or the Fisher exact test. An unpaired Wilcoxon rank sum test was used for numeric variables. P < .05 was considered to indicate a significant difference.
RESULTS: The mean (� standard deviation) volume of gadopentetate dimeglu-mine administered in the overall study group was 48 mL � 9.6 (range, 29-65 ml). The level of maximal enhancement in the pulmonary arteries was significantly higher in group 2 than in group 1 (215.8 HU � 95 vs 141.3 HU � 44) (P = .02) and was maintained throughout the entire region of interest in a greater number of examinations in group 2 than in group 1 (n = 16 [89%] vs n = 2 [10.5%]) (P < .0001). The number of diagnostic CT angiograms was significantly higher in group 2 than in group 1 (n = 17 [94%] vs n = 13 [68%]) (P = .007). Significant but transient reduction of creatinine clearance was observed in one patient with preexisting moderate chronic renal failure (0.3 mmol/kg gadolinium dose).
CONCLUSION: High-quality gadolinium-enhanced CT angiograms require the use of 16-detector row CT technology; the doses administered did not alter the renal function except transiently in one patient.