PMC9724064_01
[Case 1]: Axial CT section in a 25-year-old male demonstrating ill-defined symmetric hypodense areas involving the bilateral thalami, cerebellar white matter and bilateral frontal subcortical and deep white matter (a-c). Tiny hyperdense foci were seen within some of these regions (white arrow). A repeat CT study performed a day later revealed an increase in the hypodensities and the haemorrhagic foci with intraventricular extension of the haemorrhage and resultant obstructive hydrocephalus (d-f).
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CT imaging of the brain (Figures 1a-c) revealed ill-defined symmetrical bilateral hypodensities in the thalami, cerebellar white matter and bilateral frontal subcortical and deep white matter. Tiny hyperdense haemorrhagic foci were observed within some of these hypodense areas (Figure 1c). Repeat CT Brain imaging (Figures 1d-f), performed a day later due to the patient's clinical deterioration, revealed an increase in the haemorrhagic foci with intraventricular extension, obstructive hydrocephalus and generalized cerebral oedema.
[Case 1]: Brain MRI in a 25-year-old male diagnosed with dengue infection indicates symmetric FLAIR (a-c) and T2 hyperintense areas of altered signal intensity in the vermis, bilateral cerebellar hemispheres, thalami and bifrontal and biparietal white matter (d-f) with patchy diffusion restriction at DWI (g) - ADC not presented. Areas of blooming on GRE images (h, i), representing haemorrhages, are seen.
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MRI of the brain (Figures 2a-i) performed on the second day of admission revealed multiple, bilaterally symmetrical, hyperintense areas on fluid attenuated inversion recovery (FLAIR) and T2-weighted images involving the thalami, cerebellum, bilateral frontal and parietal subcortical and deep white matter, with patchy restricted diffusion at diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) (Figure 2g). Multiple internal foci of blooming were seen on gradient recalled echoplanar (GRE) images, representing haemorrhages (Figures 2h and 2i).
PMC9724064_02
[Case 2]: Brain MRI in a 10-year-old male showing multiple patchy FLAIR (a-c) and T2 hyperintense areas of altered signal intensity in the cerebellar hemispheres, left temporoparietal lobe and body of the corpus callosum, (d, e) with no post-contrast enhancement (f). Subtle FLAIR hyperintense signals were also seen in the inferior part of the medulla (a).
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T2-weighted and FLAIR images in the left temporoparietal lobe and bilateral cerebellar hemispheres, involving the cortex and subcortical white matter, the body of the corpus callosum and the lower medulla (Figures 3a-e). The lesions showed no diffusion restriction and no enhancement on post-contrast T1FS images (Figure 3f).
(a-c) [Case 2]: MRI screening of the spine in a 10-year-old male demonstrating T2 hyperintense signal in the inferior part of the medulla, cervicomedullary junction, upper cervical spinal cord, lower dorsal cord and conus medullaris.
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MRI screening of the spine revealed T2 hyperintense signal in the inferior part of the medulla, at the cervicomedullary junction and spinal cord up to the C3 vertebral level as well as in the terminal dorsal cord and conus medullaris from the T11 to the L1 vertebral level (Figure 4a-c).
PMC9724064_03
[Case 3]: Brain MRI of a 25-year-old male diagnosed with dengue fever showing a non-enhancing oval shaped T2 (a) and FLAIR (b) hyperintense lesion (white arrow) in the splenium of the corpus callosum. The lesion demonstrated no enhancement (c) and bright signal at DWI (d) and corresponding low values on apparent diffusion coefficient (e) with no blooming on the GRE images (f).
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T2-weighted and FLAIR images and showed no post-contrast enhancement (Figures 5a-c). The lesion revealed increased signal on diffusion imaging with corresponding low values on ADC and no blooming on GRE images (Figures 5e-f).
PMC9724064_04
[Case 4]: Brain MRI in a 55-year-old male patient with dengue fever showing a crescent-shaped extra-axial collection overlying the right cerebral convexity, appearing hyperintense on FLAIR (a, b) and T1-weighted (c, d) images and of mixed signal intensity on T2-weighted images (e, f) with blooming on GRE images (g, h), suggestive of an acute to subacute subdural haematoma.
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T1-weighted and FLAIR images and of mixed signal intensity on T2-weighted images (Figure 6a-f). The collection demonstrated blooming on GRE images, suggestive of an acute to subacute subdural haematoma (Figures 6g and 6h).
PMC9724064_05
[Case 5]: Brain MRI of a 10-year-old female with NS1 antigen seropositive status showing multiple symmetrical patchy areas of FLAIR (a-c) and T2-weighted (d-f) hyperintensities in the bilateral temporo-occipital regions and to a lesser extent in the frontoparietal regions, involving the cortex and subcortical white matter. These areas showed T1 iso to hypointense signal (g) with no post-contrast enhancement (h) and no blooming on GRE images (i).
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T2-weighted and FLAIR images in both temporo-occipital lobes and to a lesser extent in the frontoparietal regions, involving the cortex and subcortical white matter (Figures 7a-f). These areas revealed no diffusion restriction, no blooming on GRE images and no post-contrast enhancement (Figures 7f-i).
[Case 5]: Repeat brain MRI of a dengue seropositive 10-year-old female diagnosed with posterior reversible encephalopathy syndrome after 4 months showing complete resolution of the symmetrical signal abnormalities in the bilateral temporo-occipital and frontoparietal regions on axial FLAIR (a, d), T2-weighted (b, e) and T1-weighted (c, f) images.
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A follow-up brain MRI four months later revealed complete resolution of the signal abnormalities in the bilateral temporo-occipital and frontoparietal regions (Figures 8a-f).