Wagner Friedrich, Laun Frederik B, Kuder Tristan A, Mlynarska Anna, Maier Florian, Faust Jonas, Demberg Kerstin, Lindemann Linus, Rivkin Boris, Nagel Armin M, Ladd Mark E, Maier-Hein Klaus, Bickelhaupt Sebastian, Bach Michael
Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Institute of Radiology, University Hospital Erlangen, Erlangen, Germany.
PLoS One. 2017 Jun 19;12(6):e0179276. doi: 10.1371/journal.pone.0179276. eCollection 2017.
To use the "apparent diffusion coefficient" (Dapp) as a quantitative imaging parameter, well-suited test fluids are essential. In this study, the previously proposed aqueous solutions of polyvinylpyrrolidone (PVP) were examined and temperature calibrations were obtained. For example, at a temperature of 20°C, Dapp ranged from 1.594 (95% CI: 1.593, 1.595) μm2/ms to 0.3326 (95% CI: 0. 3304, 0.3348) μm2/ms for PVP-concentrations ranging from 10% (w/w) to 50% (w/w) using K30 polymer lengths. The temperature dependence of Dapp was found to be so strong that a negligence seems not advisable. The temperature dependence is descriptively modelled by an exponential function exp(c2 (T - 20°C)) and the determined c2 values are reported, which can be used for temperature calibration. For example, we find the value 0.02952 K-1 for 30% (w/w) PVP-concentration and K30 polymer length. In general, aqueous PVP solutions were found to be suitable to produce easily applicable and reliable Dapp-phantoms.
要将“表观扩散系数”（Dapp）用作定量成像参数，合适的测试流体至关重要。在本研究中，对先前提出的聚乙烯吡咯烷酮（PVP）水溶液进行了检查并获得了温度校准值。例如，在20°C的温度下，对于使用K30聚合物长度、PVP浓度范围从10%（w/w）到50%（w/w）的情况，Dapp的范围为1.594（95%置信区间：1.593，1.595）μm²/ms至0.3326（95%置信区间：0.3304，0.3348）μm²/ms。发现Dapp对温度的依赖性非常强，以至于疏忽似乎不可取。Dapp的温度依赖性通过指数函数exp(c2 (T - 20°C))进行描述性建模，并报告了确定的c2值，这些值可用于温度校准。例如，对于30%（w/w）PVP浓度和K30聚合物长度，我们得到的值为0.02952 K⁻¹。总体而言，发现PVP水溶液适合制备易于应用且可靠的Dapp体模。
