The Role of Catheter Angiography in the Diagnosis of Central Nervous System Vasculitis

Key points:

  • To understand the role of catheter angiography in the diagnosis of central nervous system vasculitis.

The role of angiography in the diagnosis of primary central nervous system vasculitis (PCNSV) emerged in the mid-1960, when were recognized recurring but not specific angiographic pattens in the inflammatory conditions of the CNS. However the comprehension of the role of DSA in this cases was made difficult by the lack of a standardized approach. In this paper, published September 5, 2016, in the Interventional Neuroradiology, the study Authors identified, in a serie of cases, the angiographic features, trying to assess its sensitivity and specificity in screening of PCNSV.

Historical background
Kussmaul and Maier (mid-1800s) An inflammatory disorder of vascular system was described for the first time (polyarteritis nodos
Harbitz (1922) he tried to distinguish “unknown form of arteritis” that primarily affected the CNS
Newman (1952) described a variant of PAN, termed noninfectious granulomatous angiitis involving the CNS (GACNS)
Cravioto (1959) argued that GACNS are not a variant of PAN
Calabrese (1988) proposed diagnostic criteria for PCNSV
Call and Fleming (1988) argued that the reversible vasoconstriction syndrome (RVCS) is not a type of PCNSV

Edgell R.C., Sarhan A., Soomro J. et al. performed a review on Pubmed of all articles about CNS vasculitis, published between 1922 and December 2014. Inclusion and exclusion criteria are available on the original article. Then, they did a list of angiographic characteristics reported to describe vasculitis, using them for a quantitative analysis.

Results
Segmental stenosis 25/25
Abrupt occlusion 10/25
Tapered occlusion 10/25
Microaneurysm 4/25
Narrowed supraclinoid ICA 3/25
Neovascularization 3/25
Segmental dilatation 3/25
Mass effect 1/25
Distal branch attenuation 1/25
Isolated stenosis 1/25
Cuffing 1/25

Authors analyzed roles of DSA and cerebral biopsy in diagnosis of PCNSV and the often discordant findings of those diagnostic tools, considering that it is not rare a positive angiography with negative biopsy, or a negative biopsy with positive DSA and post-mortem confirmation of PCNSV. They assumed that it depends on the existence of two variants of PCNSV: one affecting small vessels (small vessel disease, SVD), the other one middle vessels (middle vessel disease, MVD). MVDs are angiographically visible, involving large intracranial vessels and may have a more benign/monophasic course; SVDs involve intracranial arteries of second division branches or smaller vessels, generally have a pattern of leptomeningeal or cortical enhancement on gadolinium-enhanced MRI, a prominent elevation of CSF proteins and leukocytosis, and are beyond the resolution of DSA. Further validation is required before this hypothesis is accepted.

In conclusion, nowadays there are more data (laboratory findings, CSF analysis) to better understand PCNSV and brain biopsy is still the gold standard for their diagnosis, despite it is highly sensitive but has been shown to be diagnostic in only 30-60% of cases. Authors proposed a grading system based on angiographical findings, to maximize its sensitivity in diagnosis of PCNSV, and a systematic approach to the workup of possible CNSV.

Grading system
High probability vascular beading or alternating areas of stenosis and ectasia in multiple cerebral vessels
Medium probability the above findings in a single vessel
Low probability mass effect, isolated stenosis or occlusion

Diagnostic algorithm

Reference

– Edgell RC, Sarhan AE, Soomro J, Einertson C, Kemp J, Shirani P, Malmstrom TK, Coppens J. The Role of Catheter Angiography in the Diagnosis of Central Nervous System Vasculitis. Interv Neurol. 2016 Sep;5(3-4):194-208. Epub 2016 Aug 11.

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