Scott and White Clinic and Hospital and Department of Radiology, Texas A&M University Health Science Center, Temple, TX, USA.
J Magn Reson Imaging. 2012 Sep;36(3):704-13. doi: 10.1002/jmri.23696. Epub 2012 May 29.
To establish the minimum dose required for detection of renal artery stenosis using high temporal resolution, contrast enhanced MR angiography (MRA) in a porcine model.
Surgically created renal artery stenoses were imaged with 3 Tesla MR and digital subtraction angiography (DSA) in 12 swine in this IACUC approved protocol. Gadobutrol was injected intravenously at doses of 0.5, 1, 2, and 4 mL for time-resolved MRA (1.5 × 1.5 mm(2) spatial resolution). Region of interest analysis was performed together with stenosis assessment and qualitative evaluation by two blinded readers.
Mean signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were statistically significantly less with the 0.5-mL protocol (P < 0.001). There were no statistically significant differences among the other evaluated doses. Both readers found 10/12 cases with the 0.5-mL protocol to be of inadequate diagnostic quality (κ = 1.0). All other scans were found to be adequate for diagnosis. Accuracies in distinguishing between mild/insignificant (<50%) and higher grade stenoses (>50%) were comparable among the higher-dose protocols (sensitivities 73-93%, specificities 62-100%).
Renal artery stenosis can be assessed with very low doses (~0.025 mmol/kg bodyweight) of a high concentration, high relaxivity gadolinium chelate formulation in a swine model, results which are promising with respect to limiting exposure to gadolinium based contrast agents.
在猪模型中使用时间分辨率高的对比增强磁共振血管造影（MRA）来确定检测肾动脉狭窄所需的最小剂量。
本研究经动物伦理委员会批准，对 12 头猪进行了手术创建的肾动脉狭窄的 3T MR 和数字减影血管造影（DSA）成像。以 0.5、1、2 和 4 mL 的剂量静脉内注射钆布醇进行时间分辨 MRA（1.5×1.5 mm(2)空间分辨率）。对感兴趣区域进行分析，同时进行狭窄评估和由两位盲法读者进行定性评估。
平均信噪比（SNR）和对比噪声比（CNR）值在 0.5-mL 方案中统计学上显著较低（P<0.001）。其他评估剂量之间没有统计学差异。两位读者均发现 10/12 例 0.5-mL 方案的诊断质量不足（κ=1.0）。所有其他扫描均被认为适合诊断。在区分轻度/不显著（<50%）和更高等级狭窄（>50%）方面，较高剂量方案的准确性相当（灵敏度 73-93%，特异性 62-100%）。
可以使用高浓度、高弛豫率的钆螯合物配方的极低剂量（~0.025 mmol/kg 体重）在猪模型中评估肾动脉狭窄，这对于限制使用基于钆的造影剂的暴露是有希望的。
