"Additionally, confusion also exists in how to refer to abnormal restricted diffusion. This largely stems from the initial popularisation of DWI in stroke, which presented infarcted tissue as high signal on isotropic maps and described it merely as "restricted diffusion", implying that the rest of the brain did not demonstrate restricted diffusion, which is clearly not true. Unfortunately, this shorthand is appealing and is more widespread than using the more accurate but clumsier "diffusion demonstrates greater restriction than one would expect for this tissue.""
"The contribution of each one of these will depend on the tissue and pathology. For example, in acute cerebral infarction it is believed that the decrease in ADC values is the result of a combination of water moving into the intracellular compartment (where its diffusion is more impeded by organelles than it is in the extracellular space) and the resulting cellular swelling narrowing the extracellular space 6. Similar mechanisms result in low ADC values in highly cellular tumours (e.g. small round blue cell tumours (e.g. lymphoma/PNET) and high grade gliomas (glioblastoma))."
"grading of prostate lesions (see PI-RADS)"
"A variety of techniques for generating diffusion maps have been developed. By far the most commonly used technique relies on a spin-echo echo-planar sequence (SE-EPI), although non-EPI techniques (e.g. turbo spin-echo) are also available and are of use particularly where tissue is adjacent to or within bone, where T2* effects cause artifact, distortion and signal loss on EPI sequences 7,8."
"A variety of techniques for generating diffusion maps have been developed. By far the most commonly used technique relies on a spin-echo echo-planar sequence (SE-EPI), although non-EPI techniques (e.g. turbo spin-echo) are also available and are of use particularly where tissue is adjacent to or within bone, where T2* effects cause artifact, distortion and signal loss on EPI sequences 7,8."
"A variety of techniques for generating diffusion maps have been developed. By far the most commonly used technique relies on a spin-echo echo-planar sequence (SE-EPI), although non-EPI techniques (e.g. turbo spin-echo) are also available and are of use particularly where tissue is adjacent to or within bone, where T2* effects cause artifact, distortion and signal loss on EPI sequences 7,8."
Expected headings
"Physics"
"Clinical application"
"MRI sequence"
"General principle of diffusion-weighted imaging"
"Generating isotropic DWI and ADC maps"
"the pulse sequence that results in the generation of the various images (e.g. isotropic map, b=0, ADC)"
"The contribution of each one of these will depend on the tissue and pathology. For example, in acute cerebral infarction it is believed that the decrease in ADC values is the result of a combination of water moving into the intracellular compartment (where its diffusion is more impeded by organelles than it is in the extracellular space) and the resulting cellular swelling narrowing the extracellular space 6. Similar mechanisms result in low ADC values in highly cellular tumours (e.g. small round blue cell tumours (e.g. lymphoma/PNET) and high grade gliomas (glioblastoma))."
"A variety of techniques for generating diffusion maps have been developed. By far the most commonly used technique relies on a spin-echo echo-planar sequence (SE-EPI), although non-EPI techniques (e.g. turbo spin-echo) are also available and are of use particularly where tissue is adjacent to or within bone, where T2* effects cause artifact, distortion and signal loss on EPI sequences 7,8."
"Next, the ease with which water can diffuse is assessed in various directions; the minimum is 3 orthogonal directions (X, Y and Z), and we will use this for the rest of this explanation."
"The aforementioned process generates four sets of images: a T2* b=0 image and three diffusion-weighted images (one for each X, Y and Z direction) with the T2* signal attenuated according to how easily water can diffuse in that direction."
"Next, the ease with which water can diffuse is assessed in various directions; the minimum is 3 orthogonal directions (X, Y and Z), and we will use this for the rest of this explanation."