Dilated Juxtacortical Perivascular Spaces and Venous Cerebral Microbleeds in Cerebral Amyloid Angiopathy‐Related Inflammation

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare subtype of CAA. It is characterized by amyloid β (Aβ) depositions within walls of leptomeningeal and cortical vessels, combined with perivascular, transmural, or intramural inflammation.1 CAA-ri showed greater disease severity than noninflammatory CAA during acute and subacute phases.2 Therefore, early recognition and initiation of immunosuppressive treatment could improve the disease prognosis.1 Herein, we report a patient diagnosed with probable CAA-ri, emphasizing the imaging features presented with 5T magnetic resonance imaging (MRI). A 64-year-old woman developed chronic cognitive decline and headache, with subacute headache aggravation for 1 month. In 2017, she started with memory impairment of recent events and reduced social activities, which slowly progressed. She presented with a moderate episodic headache in March 2021. In May 2022, the headache became more severe and frequent, and the patient needed to stay in bed. She was admitted to our hospital in June 2022. On cognitive evaluation, her Mini-Mental State Examination (MMSE) score was 21, and her Montreal Cognitive Assessment (MoCA) score was 11. Other neurological examinations did not show evident abnormities. The apolipoprotein E gene test revealed ε4/ε4 homozygosity. Cerebrospinal fluid examination displayed normal open pressure, cell count, protein level, and glucose level. 18F-Florbetapir positron emission tomography displayed diffused Aβ deposition in the cerebral cortex. Three-tesla brain MRI showed bilaterally asymmetric white matter hyperintensities (WMHs; Figure1A) and disseminated cerebral microbleeds (CMBs; Figure. 1B). Five-tesla MRI further demonstrated many dilated juxtacortical perivascular spaces (jPVSs; Figure 1C,D, yellow arrows), and most CMBs were cortical, with direct connection to a small vein (Figure 1E,F, red arrows). The patient fulfilled the diagnostic criteria for probable CAA-ri. She was treated with intravenous pulsed methylprednisolone (1g/day) for 5 days, followed by oral tapering prednisone. In addition, azathioprine (25mg twice daily titrated to 50mg twice daily) was given in combination with oral prednisone. The patient's headache was relieved a few days after the methylprednisolone treatment. Three-month follow-up 5T MRI showed a reduction of WMHs in both hemispheres (Figure 1G,H). On the 9-month follow-up, her MMSE score improved to 27 and her MoCA score to 15. A 7T MRI study reported that the degree of jPVS dilation was associated with CAA severity.3 However, to our knowledge, dilated jPVSs have not been described in the CAA-ri subtype. Our 5T MRI showed many dilated jPVSs in the CAA-ri patient, which could become a promising neuroimaging marker of disease. CMBs have been one of the most prevalent neuroimaging findings in CAA-ri, with numbers much higher in CAA-ri than in noninflammatory CAA patients.1, 2 A previous 7T MRI study of CAA exhibited that 14% CMBs had a venous connection.4 Using 5T MRI, we first revealed that most CMBs showed a venous connection in CAA-ri, suggesting a possible contribution of veins to the pathogenesis. Our case prompts a better understanding of the disease pathophysiology in vivo and may help early and noninvasive identification of CAA-ri. Further studies with more patients and histological evidence are needed to confirm our findings. This study was supported by the CAMS Innovation Fund for Medical Sciences (grant number 2021-I2M-C&T-B-004). We thank Dr K. Zhang for language editing of the manuscript. All authors contributed to the acquisition and analysis of data. Y.W. and X.F. contributed to drafting the text and preparing the figure. J.N. and F.F. contributed to the conception and design of the article. Nothing to report.