PMC8589013_01
(A-D) 63yo patient with an ischemic stroke right middle cerebral artery distribution. (A) 63yo patient with an ischemic stroke right middle cerebral artery distribution. CT 3 hrs after onset of left hand weakness. The plain CT shows no acute abnormality; however, the cerebral blood flow perfusion scan (units ml/100 ml/minute cerebral blood flow for perfusion colormap) shows decreased blood flow in right middle lobe. (B) 63yo patient with an ischemic stroke right middle cerebral artery distribution. MRI T2 FLAIR sequence shows small area of diffusion restriction at 24 h after symptom onset, and after almost complete resolution of symptoms. (C) 63yo patient with an ischemic stroke right middle cerebral artery distribution. Dielectric permittivity map from an electromagnetic scan performed at 21 h after symptom onset. (D) 63yo patient with an ischemic stroke right middle cerebral artery distribution. Examples of processing algorithm using radar-based frequency domain and time domain signal analysis, signal asymmetry, tomography and direct mapping. The algorithm outputs are fused into a representative image for localization. An artificial intelligence algorithm classifies haemorrhagic stroke with a red color code, while ischaemic stroke is color-coded as blue, and this is overlaid on a greyscale permittivity map.
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F3
Figure 3 is an example of a 63-year-old patient who presented with left hand weakness due to an acute right middle cerebral artery ischemic stroke. The plain and perfusion CT (Figure 3A) were performed 3 h after onset of symptoms and shows a narrow region of ischemia in the right posterior frontal lobe with little core infarction. The electromagnetic scan (Figures 3C,D) was performed 21 h after onset, and a subsequent MRI (Figure 3B) 24 h after onset shows a small area of infarction remains.
PMC8589013_02
(A-C) 51yo patient with a hemorrhagic stroke, right basal ganglia. (A) 51yo patient with a hemorrhagic stroke, right basal ganglia. Non-contrast CT performed 2 hrs after onset of left paresis and facial droop, showing acute hemorrhage. (B) 51yo patient with a hemorrhagic stroke, right basal ganglia. Dielectric permittivity map from an electromagnetic scan performed 7 h after symptom onset. (C) 51yo patient with a hemorrhagic stroke, right basal ganglia. Examples of processing algorithm using radar-based frequency domain and time domain signal analysis, signal asymmetry, tomography and direct mapping. The algorithm outputs are fused into a representative image for localization. An artificial intelligence algorithm classifies haemorrhagic stroke with a red color code, while ischaemic stroke is color-coded as blue, and this is overlaid on a greyscale permittivity map.
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F4
Figure 4 is an example of a 51-year-old patient who presented with left paresis and facial weakness. The CT (Figure 4A) was performed 2 h after onset of symptoms and shows a 33 x 21 x 23 mm acute haematoma in the right lentiform nucleus, with some surrounding cerebral oedema. An electromagnetic scan (Figures 4B,C) performed 7 h after symptom onset shows permittivity changes in the right basal ganglia, with a lower permittivity than the corresponding contralateral brain, suggestive of blood.