Diffusion Changes in a Tumor and Peritumoral Tissue After Stereotactic Irradiation for Brain Tumors

Abstract

Changes in nADC as measured by diffusion-weighted imaging can predict response to STI.

Effect of b value on monitoring therapeutic response by diffusion-weighted imaging

“…In our study, the ADC values corresponded to the histopathologic rate of necrosis within the tumors, sug gesting that diffusion-weighted imaging has a potential for early detection of tumor necrosis after TACE, which is in agreement with the findings in theoretical diffusion models and in vitro and in vivo studies [3,[5][6][7]11] . DWI can differentiate viable and necrotic tissues by calculating ADC values because in the former, cell and intracellular membranes are intact, restricting molecular diffusion into viable tumors.…”

“…The sensitivity of diffusion-weighted imaging to water motion can be varied by changing b value, which is a function of diffusion gradient strength, duration of the gradient, and interval between diffusion gradients. Diffusion-weighted imaging has been used to predict and monitor the effect of several treatment options and to differentiate between viable and necrotic tumor tissues [3][4][5][6][7] . In these studies, a variety of b values ranging from 0 s/mm 2 to 4000 s/mm 2 were used [3][4][5][6][7] .…”

“…Diffusion-weighted imaging has recently been used to monitor tumor response after therapy. However, there are considerable discrepancies in the selection of b values in previous reports [3][4][5][6][7] . In our study, we compared different b-value DWI in evaluation of hepatic tumor necrosis after TACE in rabbits to explore the optimal b value.…”

Assessment of early treatment response after CT-guided radiofrequency ablation of unresectable lung tumours by diffusion-weighted MRI: a pilot study

“…Different modalities of early-stage follow-up examination, such as contrast-enhanced CT [8] and fluorodeoxyglucose positron emission tomography (FDG-PET), have been of great interest and their usefulness has been reported by several groups [9,10]. Another approach -MR diffusion-weighted imaging (DWI) -which is based on the measurement of motion of water molecules, has also been reported as a non-invasive evaluation modality [11][12][13][14][15][16][17][18][19]. In this method, the apparent diffusion coefficient (ADC) represents the water content and distribution, the cellular density and the cell membrane integrity, suggesting the potential usefulness of an ADC map for estimating tumour viability.…”

“…In this method, the apparent diffusion coefficient (ADC) represents the water content and distribution, the cellular density and the cell membrane integrity, suggesting the potential usefulness of an ADC map for estimating tumour viability. Indeed, DWI has been successfully used to assess the efficacy of radiotherapy [11,12], chemotherapy [13][14][15] and transcatheter arterial embolisation [16,17]. To our knowledge, only two studies have reported the use of DWI to evaluate the therapeutic outcome of RFA [18,19].…”