国产Gd-DTPA大剂量增强MRI探查脑转移瘤的临床研究

目的探讨国产Gd-DTPA三倍量（0.3mmol/kg）增强MRI检查脑转移瘤时病灶体积与病灶检出的关系。方法用国产Gd-DTPA大剂量增强MRI检查70例脑转移瘤患者。先行平扫，然后静脉注射常规量(0.1mmol/kg)国产Gd-DTPA。注射后即刻行T1WI扫描、20min后行延迟扫描。距第一次注射30min后，再注射0.2mmol/kg的Gd-DTPA，从而达到累积剂量0.3mmol/kg。第二次注射后即刻及20min后分别行T1WI扫描。对MR扫描所见进行定性、定量分析。结果三倍量增强比常规量增强扫描发现了更多的转移病灶（86→363，P＜0.01）。对于直径大于10mm的转移瘤病灶，三倍量增强的检出率和其它扫描序列之间没有显著性差异。而对于直径小于10mm的转移瘤病灶，三倍量增强的检出率和其它扫描序列之间有显著性差异（P＜0.05）。尤其对于直径小于5mm的病灶，三倍量增强扫描可以检出89.8%～97.8%的病灶，而常规量增强扫描仅能检出0.4%～0.9%的病灶（P＜0.01）。结论国产Gd-DTPA三倍量(0.3mmol/kg)增强可提高脑转移瘤病灶的检出率，尤其对于直径小于5mm的病灶效果更好。

Evaluation of IntracranialMetastases with China-made Gd-DTPA Contrast Enhancement MRI

Objective:To evaluate the effect of triple dose China-madeGd-DTPA examinations on the detection of metastatic brain lesions based on lesion size.Methods:70 patients with intracranial metastases were studied prospectively with triple dose(0.3 mmol/kg)China-made Gd-DTPA.Precontrast studies were performed,followed by intravenous injection of 0.1 mmol/kg of Gd-DTPA.T1-weighted images were acquired immediately after and at 20 minutes after injection.At 30 minutes an additional 0.2 mmol/kg of Gd-DTPA was administered(0.3 mmol/kg cumulative dose),and T1-weighted images were acquired immediately and 20 minutes later.MR findings were analyzed qualitatively and quantitatively.Results:A significant greater number of lesions was seen on the high-dose as opposed to the standard-dose images(86→363，P＜0.01).There was no significant difference in the detection rate for lesions larger than 10 mm between the triple dose contrast images and the other images.Lesions smaller than 10 mm had improved detection with triple dose images (P＜0.05),especially for the lesions smaller than 5 mm,89.8～97.8% of them were demonstrated in triple dose contrast images,whereas only 0.5～0.9% of them were detected in the conventional contrast images(P＜0.01).Conclusion:Triple dose contrast studies provide improved lesion detectability over studies performed in the same patients with a 0.1 mmol/kg dose and aid in patient diagnosis and treatment.It appears to be particularly more effective than standard dose imaging to demonstrate the lesions smaller than 5 mm.