Acquired immunodeficiency syndrome-associated cytomegalovirus encephalitis: clinical, imaging, and follow-up characteristics of 11 cases.

BACKGROUND

Patients with acquired immunodeficiency syndrome (AIDS) are susceptible to cytomegalovirus (CMV) infection due to compromised immune function, with CMV encephalitis carrying high mortality especially in those with extremely low CD4⁺ T-lymphocyte counts (<50 cells/µL). Current literature consists primarily of case reports and small cross-sectional studies, lacking large-scale systematic analyses and longitudinal follow-up. This study aims to investigate the clinical and magnetic resonance imaging (MRI) characteristics of AIDS patients with CMV encephalitis, providing evidence for early diagnosis and treatment.

METHODS

A retrospective analysis was conducted to evaluate the clinical presentations and MRI imaging characteristics of AIDS patients with CMV encephalitis.

RESULTS

Eleven patients (8 males, 3 females; median age 45 years, range, 25-59 years) were included in the study. The median peripheral CD4⁺ T-lymphocyte count was 18 (interquartile range, 8-53) cells/µL; eight patients (72.7%) had <50 cells/µL. MRI features: lesions were solitary in 4 (36.4%) and multiple in 7 (63.6%) patients, yielding a total of 51 intracranial foci. In terms of distribution, there were 15 lesions in the cerebellum (29.4%), eight lesions in the frontal lobe (15.7%), five lesions each in the brainstem, basal ganglia, and ependyma (9.8% each), three lesions each in the occipital lobe, parietal lobe, thalamus, and corpus callosum (5.9% each), and one lesion in the insula (2.0%). In terms of the signal characteristics, on T1-weighted imaging (T1WI), the lesions were iso- and hypointense in 11 (21.6%) and 40 (78.4%) cases, respectively; on T2-weighted imaging (T2WI)/fluid-attenuated inversion recovery (FLAIR), the lesions were iso- and hyperintense in 5 (9.8%) and 46 (90.2%) cases, respectively; and on diffusion-weighted imaging (DWI), the lesions were hyperintense in 48 lesions (94.1%). The apparent diffusion coefficient (ADC) values were low in 31 (60.8%) lesions, isointense in 8 (15.7%), and high in 8 (15.7%). Among the 8 patients (33 lesions) who underwent contrast-enhanced MRI, 18 lesions (54.5%) showed no enhancement, while nodular and ring-like enhancements were observed in 6 (18.2%) and 9 (27.3%) lesions, respectively. Four-year post-discharge follow-up: at discharge, eight patients showed improvement, one was discharged against medical advice, and two died. During the 4-year post-discharge follow-up, five patients were lost, and four developed immune reconstitution inflammatory syndrome (IRIS).

CONCLUSIONS

MRI provides excellent visualization of intracranial lesions in AIDS patients with CMV encephalitis, and exhibits disease-specific imaging characteristics. Beyond its diagnostic value, MRI serves as a reliable non-invasive tool for the longitudinal monitoring of therapeutic response and immune reconstitution events.