Cancer Research UK and Engineering and Physical Sciences Research Council Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Downs Rd, Sutton, Surrey SM2 5PT, England.
Radiology. 2011 Nov;261(2):573-81. doi: 10.1148/radiol.11101919. Epub 2011 Aug 18.
To describe computed diffusion weighted (DW) magnetic resonance (MR) imaging as a method for obtaining high-b-value images from DW MR imaging performed at lower b values and to investigate the feasibility of the technique to improve lesion detection in oncologic cases.
The study was approved by the institutional and research committee, and written informed consent was obtained from all patients. DW MR imaging was performed on a CuSO(4) phantom at 1.5 T with a range of b values and compared with computed DW MR imaging images synthesized from lower b values (0 and 600 sec/mm(2)). The signal-to-noise ratio (SNR) was compared, and agreement between the SNR of computed DW MR imaging and theoretical estimation assessed. Computed DW MR imaging was evaluated in 10 oncologic patients who underwent whole-body DW MR imaging with b values of 0 and 900 sec/mm(2). Computed DW MR images at computed b values of 1500 and 2000 sec/mm(2) were generated. The image quality and background suppression of acquired and computed images were rated by a radiologist using a four-point scale. The diagnostic performance for malignant lesion detection using these images was evaluated and compared by using the McNemar Test.
The SNR of computed DW MR imaging of the phantom conformed closely to theoretical predictions. Computed DW MR imaging resulted in a higher SNR compared with acquired DW MR imaging, especially at b values greater than 840 sec/mm(2). In patients, images with a computed b value of 2000 sec/mm(2) produced good image quality and high background suppression (mean scores of 2.8 and 4.0, respectively). Evaluation of images with a computed b value of 2000 sec/mm(2) resulted in higher overall diagnostic sensitivity (96.0%) and specificity (96.6%) compared with images with an acquired b value of 900 sec/mm(2) (sensitivity, 89.4%; specificity, 87.5%; P < .01).
Computed DW MR imaging in the body allows higher-b-value images to be obtained with a good SNR. Clinical computed DW MR imaging is feasible and may improve disease detection.
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101919/-/DC1.
描述计算扩散加权（DW）磁共振（MR）成像，作为一种从较低 b 值的 DW MR 成像中获得高 b 值图像的方法，并探讨该技术提高肿瘤病例中病变检测的可行性。
本研究经机构和研究委员会批准，所有患者均签署书面知情同意书。在 1.5 T 上使用 CuSO4 体模进行 DW MR 成像，范围为不同 b 值，并将其与从较低 b 值（0 和 600 sec/mm2）合成的计算 DW MR 成像图像进行比较。比较了信噪比（SNR），并评估了计算 DW MR 成像的 SNR 与理论估计值之间的一致性。对 10 例接受全身 DW MR 成像（b 值为 0 和 900 sec/mm2）的肿瘤患者进行了计算 DW MR 成像评估。生成计算 b 值为 1500 和 2000 sec/mm2 的计算 DW MR 图像。一位放射科医生使用 4 分制对采集和计算图像的图像质量和背景抑制进行评分。使用 McNemar 检验评估并比较这些图像对恶性病变检测的诊断性能。
体模的计算 DW MR 成像 SNR 与理论预测非常吻合。与采集的 DW MR 成像相比，计算 DW MR 成像的 SNR 更高，尤其是在 b 值大于 840 sec/mm2 时。在患者中，计算 b 值为 2000 sec/mm2 的图像产生了良好的图像质量和高背景抑制（平均评分为 2.8 和 4.0）。与采集 b 值为 900 sec/mm2 的图像相比，评估计算 b 值为 2000 sec/mm2 的图像时，整体诊断敏感性（96.0%）和特异性（96.6%）均更高（敏感性分别为 89.4%和 87.5%；P<.01）。
在体部进行计算 DW MR 成像可以获得具有良好 SNR 的更高 b 值图像。临床计算 DW MR 成像可行，并可能提高疾病检测能力。
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101919/-/DC1.
