Diagnosis and follow-up evaluation of central nervous system vasculitis: an evaluation of vessel-wall MRI findings

Abstract

Objective: To approach the clinical value of MRI with vessel wall imaging (VWI) in patients with central nervous system vasculitis (CNSV), we analyzed patterns of VWI findings both at the time of initial presentation and during follow-up.

Methods: Stenoocclusive lesions, vessel-wall contrast enhancement (VW-CE) and diffusion-restricted lesions were analyzed in patients with a diagnosis of CNSV. On available VWI follow-up, progression, regression or stability of VW-CE were evaluated and correlated with the clinical status.

Results: Of the 45 patients included, 28 exhibited stenoses visible on MR angiography (MRA-positive) while 17 had no stenosis (MRA-negative). VW-CE was found in 2/17 MRA-negative and all MRA-positive patients (p < 0.05). 79.1% (53/67) of stenoses showed VW-CE. VW-CE was concentric in 88.3% and eccentric in 11.7% of cases. Diffusion-restricted lesions were found more frequently in relation to stenoses with VW-CE than without VW-CE (p < 0.05). 48 VW-CE lesions in 23 patients were followed over a median time of 239.5 days. 13 VW-CE lesions (27.1%) resolved completely, 14 (29.2%) showed partial regression, 17 (35.4%) remained stable and 4 (8.3%) progressed. 22/23 patients received immunosuppressive therapy for the duration of follow-up. Patients with stable or progressive VW-CE were more likely (p < 0.05) to have a relapse (14/30 cases) than patients with partial or complete regression of VW-CE (5/25 cases).

Conclusion: Concentric VW-CE is a common finding in medium/large-sized vessel CNSV. VW-CE might represent active inflammation in certain situations. However, follow-up VWI findings proved ambiguous as persisting VW-CE despite immunosuppressive therapy and clinical remission was a frequent finding.

Keywords: Cerebral vasculitis; Follow-up; MRI; Stroke; Vessel wall imaging.

Fig. 1

Flow chart on the diagnostic work-up for PACNS (adapted from Berlit and Kraemer [3]; Birnbaum and Hellmann [7])

Fig. 2

Distribution of patients to the different subgroups of the study

Fig. 3

Stable vessel wall imaging findings on follow-up in a patient with PACNS. Vessel wall contrast enhancement of the right distal M1 segment is seen at initial presentation on vessel wall imaging (A), which remains unchanged at two-months follow-up (B) despite immunosuppressive therapy. Correlating TOF-MRA findings (C, D), showing unchanged high-grade stenosis of the affected segment

Fig. 4

Regressive vessel wall imaging findings on follow-up in a patient with PACNS. At initial presentation (A, C), there is marked vessel wall contrast enhancement of the posterior circulation, including the basilar artery (arrow) and left posterior communicating artery (arrowhead). Follow-up vessel wall imaging after ten years (B, D) shows complete resolution of vessel wall contrast enhancement of the posterior communicating artery and regressive but still persistent vessel wall contrast enhancement of the basilar artery. Correlating TOF-MRA images (E, F) demonstrate resolution of a high-grade stenosis of the left posterior communicating artery. The findings after ten years are unchanged compared to a six months follow-up scan (not shown). The patient was under immunosuppressive therapy for the whole follow-up period

Fig. 5

Progressive vessel wall imaging findings on follow-up in a patient with CNS vasculitis due to cryopyrin-associated periodic syndrome. Follow-up vessel wall imaging performed 34 months after the initial presentation (B, D) depicts contrast enhancement along the anterior vessel walls of the right A1 segment (arrow) and the left M1 segment (arrowhead), which was not identifiable on the initial MRI scan (A, C). Perivascular contrast enhancement surrounding the posterior cerebral arteries can be seen on both scans. Correlating TOF-MRA images (E, F) at both times do not show stenoses of the arteries of the circle of Willis (“MRA-negative”). The patient was under immunosuppressive therapy for the follow-up period