Stroke: Evolution from acute to chronic infarction - radiology video tutorial (CT, MRI)
Stroke: Evolution from acute to chronic infarction - radiology video tutorial (CT, MRI)
“Stroke Series” video 4 of 7: Temporal evolution of ischaemic stroke. Presented by Neuroradiologist Dr Frank Gaillard.
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Content
5.9 -> hello this is frank gaillard from
7.88 -> radiopaedia.org and today in the fourth
9.65 -> part of our series on imaging of stroke
11.48 -> we'll be having a look at the temporal
12.98 -> evolution of ischemic strokes
15.58 -> before we start let's have a look at
17.74 -> three cases which of these do you think
20.05 -> demonstrates the features of a chronic
21.76 -> infant by the end of this video the
24.31 -> answer should hopefully be obvious
27.72 -> as we saw in our previous episode the
30.599 -> earliest visible sign is direct
32.61 -> visualization of thromboembolism seen
34.95 -> here as a hyper dense middle cerebral
36.48 -> artery at this early stage one struggles
39.059 -> to make out even the earliest of
40.41 -> parenchymal changes perhaps with the eye
42.51 -> of faith there is slight blurring and
44.64 -> loss of gray white matter interface of
46.53 -> the lenta form nucleus and the insular
48.18 -> cortex if one were to perform an MRI
51.29 -> vivid restricted diffusion bright on DWI
54.51 -> with corresponding low signal on ADC
56.909 -> would be seen as in this scan from
59.25 -> another patient going back to our
61.53 -> previous patient over the next couple of
63.18 -> days the in fact becomes easily visible
65.339 -> as a region of well demarcated low
67.229 -> attenuation in this case with some areas
69.75 -> of small hemorrhagic transformation this
72.18 -> is associated with swelling as
73.77 -> extracellular and intracellular fluid
75.75 -> accumulates this is due to cellular
78.39 -> swelling and breakdown of the
79.65 -> blood-brain barrier there is
81.18 -> corresponding positive Mass Effect
83.78 -> maximal swelling occurs during the first
86.07 -> week typically maximal at day 3 or so in
89.64 -> this case swelling is so severe that a
91.409 -> decompressive craniectomy is performed
93.24 -> to try and alleviate raised intracranial
94.77 -> pressure and herniation with time
97.8 -> swelling starts to recede as seen here
100.02 -> on this day 11 scan note also how the
102.72 -> reduced edema and associated influx of
105.36 -> inflammatory cells histologically the
107.43 -> density of the in fact increases this
110.7 -> increase in density and reduction in
112.71 -> swelling can in some patients almost
114.42 -> exactly mimic normal brain during the
116.549 -> second or third week following
118.02 -> infarction as is seen in this patient
120.42 -> where the left-sided infarct superior
122.19 -> vanish this phenomena is called fogging
125.07 -> and is the focus of our next video note
127.89 -> however that just because it appears
129.539 -> normal on CT does not mean the stroke
131.4 -> has resolved administration of contrast
134.489 -> either with CT or in this case MRI
136.739 -> easily demonstrates the region due to
138.75 -> persistent breakdown of the blood-brain
140.31 -> barrier resulting in leakage of contrast
142.44 -> into the infarcted tissues this is
145.23 -> visualized as a region of Jireh form
147.18 -> cortical enhancement
149.33 -> continued volume loss results in
151.22 -> negative mass effect on the surrounding
152.51 -> brain seen here as X evacuate dilatation
155.09 -> of the lateral ventricle and continued
156.98 -> decrease in the density approaching that
158.78 -> of CSF after a number of months little
161.78 -> change will occur with the region
163.19 -> appearing as a focal loss of tissue
164.96 -> sometimes leaving a vague ghost of the
167.06 -> previous jar or pattern as seen in this
169.19 -> patient who had an in fact a number of
170.99 -> years earlier note how all cerebral
173.69 -> tissue in the region is lost replaced by
175.79 -> fluid as demonstrated here following CSF
178.82 -> on all sequences including
180.26 -> diffusion-weighted imaging and ADC maps
182.95 -> so if we go back and put all these CT
185.81 -> images together we can see a general
187.43 -> pattern of evolution the earliest
189.74 -> parenchymal change is seen even a few
191.66 -> hours after onset of ischemia is subtle
194.06 -> loss of gray white matter
195.23 -> differentiation gradually over the next
197.78 -> few days the region becomes more defined
200.06 -> and lower attenuating and swells such at
202.43 -> the middle of the first week there is
204.02 -> maximal swelling after this swelling
206.36 -> gradually subsides and attenuation
208.55 -> decreases in some patients returning to
211.31 -> near normal so-called falton phenomenon
213.95 -> eventually the infarcted tissue is
216.23 -> removed leaving behind cystic and
217.94 -> carefully Malasia it is important to
220.4 -> note that the size of the infarct
221.78 -> therapeutic interventions and patient
223.76 -> factors all influence exact timing
226.69 -> either end of the process the
229.07 -> appearances and timing are predictable
230.78 -> but during the subacute phases exact
232.76 -> aging of an infarct can be difficult
235.819 -> going back to our three cases it should
238.4 -> now be obvious that image a is of a
240.29 -> chronic stroke the region of infarction
242.45 -> is very sharply demarcated and is a very
244.609 -> low-density similar to that of CSF and
246.799 -> most importantly there is negative mass
249.019 -> effect with widening of the adjacent
250.459 -> sulci and x-pac your dilatation of the
252.859 -> lateral ventricle in contrast images B
256.579 -> and C are sub acute in facts they are
259.82 -> often less well demarcated especially
261.859 -> early on and although they are of lower
263.84 -> attenuation the normal brain tissue they
265.669 -> are still very much denser than CSF most
268.669 -> importantly they have positive mass
270.169 -> effect with the Faceman of the overlying
271.669 -> soul high in our next episode we'll go
273.979 -> into the details of folding phenomenon a
276.05 -> little more you can of course see many
278.449 -> more cases and get much more detailed
280.25 -> explanation on radiopaedia.org see you
282.74 -> again soon
292.11 -> you
Source: https://www.youtube.com/watch?v=Rb2YPGwwing