Dataset for Fig 5.

A number of restricted diffusion (RD) imaging techniques, such as diffusion kurtosis (DK) imaging and Q space imaging, have been developed and proven to be useful for the diagnosis of diseases, including cerebral gliomas and cerebrovascular infarction. In particular, apparent diffusion coefficient (ADC) subtraction method (ASM) imaging has become available recently as a novel RD imaging technique. ASM is based on the difference between the ADC values in an image pair of two ADC maps, ADC basic (ADCb) and ADC modify (ADCm), which are created from diffusion-weighted images taken using short and long effective diffusion times, respectively. The present study aimed to assess the potential of different types of ASM imaging by comparing them with DK imaging which is the gold-standard RD imaging technique. In the present basic study using both polyethylene glycol phantom and cell-containing bio-phantom, three different types of ASM images were created using different calculation processes. ASM/A is an image calculated by dividing the absolute difference between ADCb and ADCm by ADCb several times. By contrast, ASM/S is an image created by dividing the absolute difference between ADCb and ADCm by the standard deviation of ADCb several times. As for positive ASM/A image (PASM/A), the positive image, which was resultant after subtracting ADCb from ADCm, was divided by ADCb several times. A comparison was made between the types of ASM and DK images. The results showed the same tendency between ASM/A in addition to both ASM/S and PASM/A. By increasing the number of divisions by ADCb from three to five times, ASM/A images transformed from DK-mimicking to more RD-sensitive images compared with DK images. These observations suggest that ASM/A images may prove useful for future clinical applications in RD imaging protocols for the diagnosis of diseases.

诸多受限扩散（restricted diffusion, RD）成像技术已被开发并证实可用于包括脑胶质瘤、脑血管梗死在内的多种疾病的诊断，例如扩散峰度（diffusion kurtosis, DK）成像与Q空间成像。其中，表观扩散系数（apparent diffusion coefficient, ADC）减影法（ASM）成像作为一种新型RD成像技术于近年问世。ASM成像基于两幅ADC图的ADC值差异构建：这两幅ADC图分别为基础ADC（ADCb）与修正ADC（ADCm），二者由分别采用短、长有效扩散时间采集的扩散加权图像生成。本研究旨在对比不同类型ASM成像与作为RD成像金标准的DK成像，以评估各类ASM成像的应用潜力。本基础研究同时采用聚乙二醇体模与含细胞生物体模，通过不同计算流程构建了三种ASM成像。其中，ASM/A成分为将ADCb与ADCm的绝对差值多次除以ADCb得到的图像；与之相对，ASM/S成分为将ADCb与ADCm的绝对差值多次除以ADCb的标准差得到的图像。正向ASM/A成像（PASM/A）则是将ADCm减去ADCb后得到的差值图像多次除以ADCb所生成的结果。本研究对各类ASM成像与DK成像进行了对比分析。结果显示，ASM/A、ASM/S与PASM/A三者呈现出一致的变化趋势：当ADCb的除数次数由3次增加至5次时，ASM/A成像从模拟DK成像的模式转变为相较于DK成像对RD更为敏感的模式。上述结果表明，ASM/A成像有望在未来的RD成像临床诊断方案中展现应用价值。