case_images: PMC11655173_01
case_images: Neuroimaging results pre-lecanemab/amyloid-related imaging abnormalities (ARIA). Two microbleeds are identified using T2* magnetic resonance imaging (MRI) (a). Positron emission tomography imaging using 18F-flutemetamol showed amyloid beta plaque deposition in the frontal, lateral temporal and parietal lobe, posterior cingulate gyri, praecuneus, and striatum (b). The white arrows show microbleeds.
case_images: PSYG-25-0-g003.jpg
case_images: PMC11655173_01_PSYG-25-0-g003.jpg
case_images: psyg13231-fig-0001
case_images: Mini-Mental State Examination (MMSE) score was 26/30 and her score on the Japanese version of the Montreal Cognitive Assessment (MoCA) was 17/30, indicating disorientation and short-term memory impairment, affecting daily life. Magnetic resonance imaging (MRI) of the head revealed mild atrophy of the left hippocampus and parahippocampal gyrus, along with two microbleeds (Fig. 1a). Positron emission tomography imaging using 18F-flutemetamol revealed amyloid plaque deposition in the frontal, lateral temporal and parietal lobes, posterior cingulate gyrus, praecuneus, and striatum (Fig. 1b).
case_images: Magnetic resonance imaging (MRI) prior to treatment, and changes following treatment with lecanemab. Baseline MRI showing only subtle white matter hyperintensity on fluid-attenuated inversion recovery (FLAIR). The white arrows show subtle white matter hyperintensity on FLAIR (a) and only two microbleeds on T2* weighted image (WI) (one of the two microbleeds is indicated by arrows in b, the white arrow shows microbleed). MRI taken 6 days following symptom onset showing extensive high-signal areas in the white matter on FLAIR. The white arrows show extensive high-signal areas in the white matter on FLAIR (c) and extensive microbleeds along the cortex and subcortical white matter on T2* WI. The white arrows show extensive microbleeds along the cortex and subcortical white matter on T2*WI (d). Consequently, the patient was diagnosed with severe amyloid-related imaging abnormalities (ARIA) (E) and ARIA with haemorrhage (ARIA-H) infections. The apparent diffusion coefficient map indicates increased diffusion. The white arrows indicate the presence of vasogeniv edema (e), indicating the presence of vasogenic oedema. Susceptibility-weighted imaging (SWI), revealed numerous small microbleeds along the cortex. The white arrow show indicate new microbleeds (f), with more than 100 new microbleeds appearing throughout the brain. Despite numerous microbleeds, imaging findings did not indicate any superficial siderosis (data not shown).
case_images: PSYG-25-0-g001.jpg
case_images: PMC11655173_01_PSYG-25-0-g001.jpg
case_images: psyg13231-fig-0002
case_images: On susceptibility-weighted imaging (SWI), this number increased to more than 100 (Fig. 2b,d,f).
case_images: Changes in perivascular spaces before and after lecanemab treatment. Baseline T2 weighted image (WI) showing dilation of the perivascular space, thought to reflect impaired glymphatic drainage (a). At the onset of amyloid-related imaging abnormalities (ARIA), the dilation of the perivascular space worsened despite swelling of the perivascular space (b). The white arrows show dilation of the perivascular space.
case_images: PSYG-25-0-g004.jpg
case_images: PMC11655173_01_PSYG-25-0-g004.jpg
case_images: psyg13231-fig-0003
case_images: Multiple microinfarctions were observed in the temporal and occipital lobes of the cerebral cortex, as well as in the subcortical white matter (Fig. 3).
case_images: Multiple microinfarctions following lecanemab treatment. Thin-slice diffusion-weighted image (DWI) (slice thickness = 2 mm with gaplessness) performed 6 days following symptom onset revealed numerous punctate high-signal areas. The white arrows show microinfarctions.
case_images: PSYG-25-0-g002.jpg
case_images: PMC11655173_01_PSYG-25-0-g002.jpg
case_images: psyg13231-fig-0004
case_images: Interestingly, despite progression of cerebral oedema, the perivascular spaces had expanded compared to baseline (Fig. 4).
case_images: Temporal changes in amyloid-related imaging abnormalities (ARIA) onset: Imaging improvements and cognitive function progression following steroid treatment.
case_images: PSYG-25-0-g005.jpg
case_images: PMC11655173_01_PSYG-25-0-g005.jpg
case_images: psyg13231-fig-0005
case_images: By the end of treatment, her headaches, left hemiparesis, and confusion had resolved, and follow-up MRI revealed a significant improvement in ARIA-E (Fig. 5).