Diagnosis and management of adult primary angiitis of the central nervous system: an international survey on current practices

Magnetic resonance spectroscopy for discriminating primary angiitis of the central nervous system from gliomas and lymphomas

OBJECTIVE

Conventional imaging often struggles to differentiate between primary angiitis of the central nervous system (PACNS) and intracranial tumors. This study aims to evaluate the application value of proton magnetic resonance spectroscopy (1H-MRS) in distinguishing PACNS from intracranial tumors.

METHODS

This study collected data from 10 patients with PACNS and 15 patients with intracranial tumors (10 gliomas and 5 lymphomas) confirmed by pathological biopsy. The levels of choline (Cho), creatine (Cr), and N-acetylaspartate (NAA) in the lesion areas and contralateral normal brain tissue were measured and analyzed using 1H-MRS, and the ratios of Cho/Cr, NAA/Cr, and Cho/NAA were calculated. The diagnostic efficacy of 1H-MRS in distinguishing PACNS from intracranial tumors was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC).

RESULTS

Compared to contralateral normal brain tissue, significant differences were observed in the ratios of Cho/Cr, NAA/Cr, and Cho/NAA between the lesion areas of PACNS and intracranial tumors (P < 0.001). After correcting for the corresponding normal brain tissue spectra, the NAA/Cr ratio in PACNS lesion areas was significantly higher than in intracranial tumor lesions (0.90 vs. 0.25, P < 0.001), and the Cho/NAA ratio was significantly lower in PACNS lesions (1.98 vs. 9.00, P < 0.001), while the difference in Cho/Cr was not significant (1.59 vs. 1.94, P = 0.405). When the corrected NAA/Cr ratio was ≥ 0.71, the ROC-AUC for diagnosing PACNS was 1.00, with both specificity and sensitivity at 100%. The subgroup analysis of glioma/lymphoma yielded similar results.

CONCLUSION

The ratios of NAA/Cr and NAA/Cho are significantly meaningful in differentiating PACNS from intracranial tumors, and 1H-MRS can be an effective tool for distinguishing these two conditions.

Inflammatory disorders that affect the cerebral small vessels

ABSTRACT

This comprehensive review synthesizes the latest advancements in understanding inflammatory disorders affecting cerebral small vessels, a distinct yet understudied category within cerebral small vessel diseases (SVD). Unlike classical SVD, these inflammatory conditions exhibit unique clinical presentations, imaging patterns, and pathophysiological mechanisms, posing significant diagnostic and therapeutic challenges. Highlighting their heterogeneity, this review spans primary angiitis of the central nervous system, cerebral amyloid angiopathy-related inflammation, systemic vasculitis, secondary vasculitis, and vasculitis in autoinflammatory diseases. Key discussions focus on emerging insights into immune-mediated processes, neuroimaging characteristics, and histopathological distinctions. Furthermore, this review underscores the importance of standardized diagnostic frameworks, individualized immunomodulation approaches, and novel targeted therapies to address unmet clinical demands.

Integrated Metabolomics and Transcriptomics Analyses Reveal Metabolic Changes in Primary Angiitis of the Central Nervous System

Purpose

Metabolic characterization of primary angiitis of the central nervous system (PACNS) is crucial for understanding the disease pathogenesis and progression mechanisms, but it has not been reported in patients. This study aimed to explore changes in the plasma metabolome during the active and remission phases of PACNS and identify potential biomarkers.

Methods

We collected plasma samples from 35 patients with PACNS during the active and remission phases and 22 samples from patients with non-inflammatory disease as controls. Liquid and gas chromatography-mass spectrometry were used to analyze 63 plasma samples from 57 patients metabolically. Meanwhile, we cross-validated the metabolomics results with brain tissue transcriptomic data from comprehensive gene expression databases, enhancing the reliability of our conclusions.

Results

A total of 3,233 metabolites were identified. Enrichment analysis showed significant changes in lactate/amino acid/glycerol-pyruvic-tricarboxylic acid, glycerophospholipid/sphingolipid-membrane metabolism, lysine/tryptophan-essential amino acid metabolism, and uracil metabolism pathways during the active phase of PACNS. These findings were confirmed in both the remission phase of PACNS patients and the transcriptomic samples. Meanwhile, metabolic abnormalities in patients with PACNS were observed with benzoxazole, sesquiterpenoid, and octyl-phenolic products, and enrichment of environmental pollutants and their estrogen-like effects. Twelve metabolites, including D-Ribose, 13s-HPODE, and C16 Sphinganine, showed potential diagnostic and therapeutic evaluation value.

Conclusion

Our study identified potential biomarkers and metabolic characteristics of PACNS using integrated metabolomics and transcriptomics approaches. These findings highlight the importance of understanding PACNS from a metabolic perspective and guide future diagnostic and therapeutic strategies.

Cerebral Amyloid Angiopathy-Related Inflammation and Biopsy-Positive Primary Angiitis of the CNS: A Comparative Study

BACKGROUND AND OBJECTIVES

Cerebral amyloid angiopathy-related inflammation (CAA-RI) and biopsy-positive primary angiitis of the CNS (BP-PACNS) have overlapping clinicoradiologic presentations. It is unknown whether clinical and radiologic features can differentiate CAA-RI from BP-PACNS and whether both diseases have different relapse rates. The objectives of this study were to compare clinicoradiologic presentations and relapse rates in patients with CAA-RI vs BP-PACNS.

METHODS

Patients with CAA-RI and BP-PACNS were enrolled from 2 retrospective multicenter cohorts. Patients with CAA-RI were biopsy-positive or met probable clinicoradiologic criteria. Patients with BP-PACNS had histopathologic confirmation of CNS angiitis, with no secondary etiology. A neuroradiologist read brain MRIs, blinded to the diagnosis of CAA-RI or BP-PACNS. Clinicoradiologic features were compared using univariable logistic regression models. Relapse rates were compared using a univariable Fine-Gray subdistribution hazard model, with death as a competing risk.

RESULTS

This study enrolled 104 patients with CAA-RI (mean age 73 years, 48% female sex) and 52 patients with BP-PACNS (mean age 45 years, 48% female sex). Patients with CAA-RI more often had white matter hyperintense lesions meeting the probable CAA-RI criteria (93% vs 51%, p < 0.001), acute subarachnoid hemorrhage (15% vs 2%, p = 0.02), cortical superficial siderosis (27% vs 4%, p < 0.001), ≥1 lobar microbleed (94% vs 26%, p < 0.001), past intracerebral hemorrhage (17% vs 4%, p = 0.04), ≥21 visible centrum semiovale perivascular spaces (34% vs 4%, p < 0.01), and leptomeningeal enhancement (70% vs 27%, p < 0.001). Patients with BP-PACNS more often had headaches (56% vs 31%, p < 0.01), motor deficits (56% vs 36%, p = 0.02), and nonischemic parenchymal gadolinium enhancement (82% vs 16%, p < 0.001). The prevalence of acute ischemic lesions was 18% in CAA-RI and 22% in BP-PACNS (p = 0.57). The features with the highest specificity for CAA-RI were acute subarachnoid hemorrhage (98%), cortical superficial siderosis (96%), past intracerebral hemorrhage (96%), and ≥21 visible centrum semiovale perivascular spaces (96%). The probable CAA-RI criteria had a 71% sensitivity (95% CI 44%-90%) and 91% specificity (95% CI 79%-98%) in differentiating biopsy-positive CAA-RI from BP-PACNS. The rate of relapse in the first 2 years after remission was lower in CAA-RI than in BP-PACNS (hazard ratio 0.46, 95% CI 0.22-0.96, p = 0.04).

CONCLUSION

Clinicoradiologic features differed between patients with CAA-RI and those with BP-PACNS. Specific markers for CAA-RI were hemorrhagic signs of subarachnoid involvement, past intracerebral hemorrhage, ≥21 visible centrum semiovale perivascular spaces, and the probable CAA-RI criteria. A biopsy remains necessary for diagnosis in some cases of CAA-RI. The rate of relapse in the first 2 years after disease remission was lower in CAA-RI than in BP-PACNS.

Comparison of patients with biopsy positive and negative primary angiitis of the central nervous system

OBJECTIVE

There is limited evidence on when to obtain a central nervous system (CNS) biopsy in suspected primary angiitis of the central nervous system (PACNS). Our objective was to identify which clinical and radiological characteristics were associated with a positive biopsy in PACNS.

METHODS

From the multicentre retrospective Cohort of Patients with Primary Vasculitis of the CNS (COVAC), we included adults with PACNS based on a positive CNS biopsy or otherwise unexplained intracranial stenoses with additional findings supportive of vasculitis. Baseline findings were compared between patients with a positive and negative biopsy using logistic regression models.

RESULTS

Two hundred patients with PACNS were included, among which a biopsy was obtained in 100 (50%) and was positive in 61 (31%). Patients with a positive biopsy were more frequently female (odds ratio [OR] 2.90; 95% CI: 1.25, 7.10; P = 0.01) and more often presented with seizures (OR 8.31; 95% CI: 2.77, 33.04; P < 0.001) or cognitive impairment (OR 2.58; 95% CI: 1.11, 6.10; P = 0.03). On imaging, biopsy positive patients more often had non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (OR 52.80; 95% CI: 15.72, 233.06; P < 0.001) or ≥1 cerebral microbleed (OR 8.08; 95% CI: 3.03, 25.13; P < 0.001), and less often had ≥1 acute brain infarct (OR 0.02; 95% CI: 0.004, 0.08; P < 0.001). In the multivariable model, non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (adjusted OR 8.27; 95% CI: 1.78, 38.46; P < 0.01) and absence of ≥1 acute brain infarct (adjusted OR 0.13; 95% CI: 0.03, 0.65; P = 0.01) were significantly associated with a positive biopsy.

CONCLUSION

Baseline clinical and radiological characteristics differed between biopsy positive and negative PACNS. These results may help physicians individualize the decision to obtain a CNS biopsy in suspected PACNS.