Applications of DWI had been limited to CNS due to effects of respiration, cardiac movement, peristalsis and blood flow may effect on image quality in these parts of the body ( 11). Also, results of many clinical studies show that increase in the ADC value suggest a better treatment outcome in clinical studies ( 9, 10).ĭWI has been applied to the evaluation of central nervous system (CNS) pathologies especially in stroke, for last two decades. Increase of ADC value was accepted as response to therapy in many animal studies ( 8). Many researchers have reported that DWI has potential for evaluating tumor response during treatment. These histopathologic characteristics reduce the extracellular matrix and the diffusion space of water protons in the extracellular areas, with a resultant decrease in the ADC value ( 6, 7).Īs well as tumor detection and characterization, DWI has been widely used for predicting and monitoring response to therapy. Generally, malignant tumors have enlarged nuclei and show hypercellularity. The degree of restriction to water diffusion is correlated with tissue cellularity and integrity of cell membranes ( 5). So, significant proportions of signal on DWI originated from intravascular space ( 4). In biologic tissues, the DWI signal is derived from the motion of water molecules in the extracellular space, intracellular space and intravascular space ( 2). By drawing regions of interests on these maps, the ADCs of different tissues can be derived ( 3). ADC value is calculated for each pixel of the image and is displayed as a parametric map. Apparent-diffusion-coefficient (ADC) is a quantitative parameter calculated from DWI combines the effects of capillary perfusion and water diffusion ( 2). DWI measures the random (Brownian) extra, intra and transcellular motion of water molecules ( 1). We think it can be added to conventional magnetic resonance imaging (MRI) sequences.ĭiffusion-weighted-imaging (DWI) provides microscopic information from water protons which is not possible using conventional magnetic resonance imaging (MRI). DWI may be a routine sequence in oncologic settings and it provides much useful information about tumoral tissue. Most of the studies suggested that malignant tumors had lower ADC values than benign ones. Apparent-diffusion-coefficient (ADC) value is quantitative parameter of DWI which reflects diffusion movements of water molecules in various tissues. One of the most prominent contributions of DWI is differentiation of between malignant and benign tumoral process. As well as tumor detection and characterization, DWI has been widely used for predicting and monitoring response to therapy.
Some technologic advances lead to using of DWI in the extracranial sites such as abdomen and pelvis. DWI has been applied to the evaluation of central nervous system (CNS) pathologies. In this article, we present oncologic applications of DWI in the parts of the body. DWI has important advantages as do not require contrast medium, very quick technique and it provides qualitative and quantitative information that can be helpful for tumor assessment. There is growing interest in the applications of diffusion-weighted-imaging (DWI) in oncologic area for last ten years.
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