Krautmacher Carsten, Willinek Winfried A, Tschampa Henriette J, Born Mark, Träber Frank, Gieseke Jürgen, Textor Hans J, Schild Hans H, Kuhl Christiane K
Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn, Germany.
Radiology. 2005 Dec;237(3):1014-9. doi: 10.1148/radiol.2373041672. Epub 2005 Oct 19.
To prospectively and intraindividually compare the effect of magnetic resonance (MR) imaging at a higher magnetic field strength (3.0 T) on contrast-to-noise ratio (CNR) at different doses of a T1-shortening contrast agent in patients with contrast-enhancing brain lesions, with 1.5-T MR imaging as a reference standard.
Institutional review board approval and informed consent were obtained for all patient and volunteer studies. Twelve patients (six women, six men; mean age, 58 years; range, 29-76 years) with 12 enhancing brain lesions (11 patients with primary brain tumors and one with a solitary cerebral metastasis) underwent contrast material-enhanced MR imaging three times, on three separate days: once at 1.5 T with a full dose of 0.10 mmol/kg gadopentetate dimeglumine, once at 3.0 T with a full dose, and once at 3.0 T with half that dose, 0.05 mmol/kg. The same contrast-enhanced T1-weighted spin-echo images (repetition time msec/echo time msec, 500/12; section thickness, 5 mm; matrix, 256 x 205) were obtained at both 3.0 T and 1.5 T after prior optimization of parameters at 3.0 T. The number and conspicuity of enhancing brain lesions were assessed with blinded clinical image reading. Signal-to-noise ratio and CNR were determined with region of interest analysis of enhancing lesions and normal contralateral white matter. For 3.0 T with half the standard dose and with the full dose, CNR of lesions was intraindividually compared with CNR at 1.5 T with the full dose by using the Wilcoxon matched-pairs signed rank test.
At 3.0 T and full dose, CNR was 2.8-fold higher than that at 1.5 T and full dose (P < .001). At the same time, higher lesion conspicuity at clinical image reading was observed. With only half the standard dose, MR imaging at 3.0 T still yielded higher CNR (1.3-fold higher) than that with full dose at 1.5 T (P < .01).
With the same amount of contrast agent, MR imaging at 3.0 T offered a significantly higher CNR of enhancing cerebral lesions, compared with that at 1.5 T; even with the dose reduced by half, CNR was still higher at 3.0 T.
以前瞻性和个体内比较的方式，在增强脑病变患者中，将更高磁场强度（3.0 T）的磁共振（MR）成像与不同剂量的T1缩短型对比剂对对比噪声比（CNR）的影响进行比较，并以1.5 T MR成像作为参考标准。
所有患者和志愿者研究均获得机构审查委员会批准并取得知情同意。12例患者（6名女性，6名男性；平均年龄58岁；范围29 - 76岁），有12个增强性脑病变（11例原发性脑肿瘤患者和1例孤立性脑转移患者），在三个不同日期接受三次对比剂增强MR成像：一次在1.5 T使用全剂量0.10 mmol/kg钆喷酸葡胺，一次在3.0 T使用全剂量，一次在3.0 T使用半剂量0.05 mmol/kg。在3.0 T预先优化参数后，在3.0 T和1.5 T均获得相同的对比增强T1加权自旋回波图像（重复时间毫秒/回波时间毫秒，500/12；层厚5 mm；矩阵，256×205）。通过盲法临床图像解读评估增强性脑病变的数量和清晰度。通过对增强病变和对侧正常白质进行感兴趣区分析来确定信噪比和CNR。对于3.0 T半标准剂量和全剂量的情况，使用Wilcoxon配对符号秩检验将病变的CNR与1.5 T全剂量时的CNR进行个体内比较。
在3.0 T全剂量时，CNR比1.5 T全剂量时高2.8倍（P <.001）。同时，在临床图像解读中观察到病变清晰度更高。仅使用半标准剂量时，3.0 T的MR成像仍比1.5 T全剂量时产生更高的CNR（高1.3倍）（P <.01）。
使用相同量的对比剂时，与1.5 T相比，3.0 T的MR成像对增强性脑病变的CNR显著更高；即使剂量减半，3.0 T时的CNR仍然更高。
