Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna/Vienna General Hospital, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
Radiology. 2013 Jul;268(1):161-9. doi: 10.1148/radiol.13121733. Epub 2013 Feb 28.
To investigate the diagnostic value of a half dose compared with a full dose of gadobenate dimeglumine in the assessment of synovitis or tenosynovitis in the wrist and finger joints in patients with early rheumatoid arthritis (RA) and a disease activity score greater than 3.2.
With institutional review board approval and informed consent, 57 patients with early RA underwent 3-T magnetic resonance (MR) imaging with two different doses of contrast media. The contrast enhancement was measured in inflamed synovial tissue at half dose (0.05 mmol per kilogram of body weight) and at full dose (0.1 mmol/kg) by using T1-weighted sequences with fat saturation. The differences and the correlation of signal intensities (SIs) at half- and full-dose sequences were compared by using the paired t test and Pearson correlations. Image quality, Rheumatoid Arthritis MRI Score (RAMRIS), and tenosynovitis score on half- and full-dose images were compared by two observers using the Wilcoxon test. Interrater agreement was assessed by using κ statistics.
A significant difference in SI was found between half-dose and full-dose gadobenate dimeglumine-enhanced synovial tissue (mean: 914.35 ± 251.1 vs 1022 ± 244.5, P < .001). Because the SI showed high correlation between the ratio at half dose and full dose (r = 0.875), the formula, ratio of synovial enhancement to saline syringe at full dose = 0.337 + 1.070 × ratio of synovial enhancement to saline syringe at half dose, can be used to convert the normalized value of half dose to full dose. However, no difference in RAMRIS (score 0 in 490 of 1026 joints; score 1 in 344; score 2 in 158; and score 3 in 34) or tenosynovitis scores in grading synovitis or tenosynovitis in image quality and in assessment of synovial enhancement was detected between half-dose and full-dose images (P = 1).
Postcontrast synovial SIs showed high correlation between half dose and full dose, and image quality was rated identically. Therefore, half-dose gadobenate dimeglumine at 3-T MR imaging may be sufficient for assessing synovitis or tenosynovitis in early RA.
探讨半剂量与全剂量钆喷酸葡胺在评估早期类风湿关节炎（RA）患者腕关节和手指关节滑膜炎或腱鞘炎中的诊断价值，这些患者的疾病活动评分大于 3.2。
本研究经机构审查委员会批准并获得患者知情同意，57 例早期 RA 患者接受了两种不同剂量对比剂的 3-T 磁共振（MR）成像。通过使用带有脂肪饱和的 T1 加权序列，在半剂量（0.05mmol/kg 体重）和全剂量（0.1mmol/kg）下测量炎症性滑膜组织的对比增强，测量半剂量和全剂量序列的信号强度（SI）差异，并通过配对 t 检验和 Pearson 相关进行比较。两名观察者使用 Wilcoxon 检验比较半剂量和全剂量图像的图像质量、类风湿关节炎 MRI 评分（RAMRIS）和腱鞘炎评分。使用κ统计评估观察者间的一致性。
半剂量和全剂量钆喷酸葡胺增强滑膜组织的 SI 存在显著差异（平均值：914.35±251.1 与 1022±244.5，P＜0.001）。由于 SI 之间存在高相关性，因此可以使用公式（半剂量时的增强比值/生理盐水注射器比值=0.337+1.070×全剂量时的增强比值/生理盐水注射器比值）将半剂量的归一化值转换为全剂量值。然而，在图像质量和评估滑膜增强方面，半剂量和全剂量图像之间在滑膜炎或腱鞘炎分级的 RAMRIS（1026 个关节中 0 分 490 个，1 分 344 个，2 分 158 个，3 分 34 个）或腱鞘炎评分方面均未检测到差异（P=1）。
半剂量和全剂量之间的对比后滑膜 SI 相关性较高，且图像质量的评分相同。因此，3-T MR 成像时使用半剂量钆喷酸葡胺可能足以评估早期 RA 患者的滑膜炎或腱鞘炎。
