Page 59 - Read Online

Topic: The Role of Inflammation in Cerebral Aneurysm

Advances in the imaging of cerebral aneurysm

inflammation

Michael R. Levitt, M. Yashar S. Kalani, Karam Moon, Cameron G. McDougall, Felipe C. Albuquerque
Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center,
Phoenix, AZ 85013, USA.

ABSTRA CT

Cerebral aneurysm formation, growth and rupture are thought to be the result of a complex interaction between cerebrovascular
hemodynamics and pathobiology. Recently, new evidence has emerged regarding the role of inflammation in the walls of cerebral
aneurysms. Noninvasive methods to characterize the degree of inflammation in aneurysms could enable clinicians to estimate the risk
of future aneurysm growth and rupture, influencing treatment. This review examines emerging techniques of imaging inflammatory
biomarkers in cerebral aneurysms.
Key words: Ferrosoferric oxide, inflammation, intracranial aneurysm, magnetic resonance angiography, subarachnoid hemorrhage

INTRODUCTION these studies rely on histological analysis of aneurysm
tissue.
Intracranial aneurysms are a substantial source of
intracranial hemorrhage worldwide. Many aneurysms Recently, the development of noninvasive imaging
are detected incidentally, and the treatment calculus of inflammatory markers has been developed and
regarding unruptured aneurysms remains debatable. applied to the study of cerebral aneurysms. Preliminary
Early studies relied on aneurysm diameter, positing results are promising that the link between aneurysm
that small aneurysms nearly never ruptured; however, rupture risk and inflammation is strong, and that such
[1]
recent data suggest that some small aneurysms confer inflammation can be imaged in a clinical setting.
a significant rupture risk. More recently, complex
[2]
morphologic and hemodynamic characteristics IMAGING OF MYELOPEROXIDASE
have been suggested to risk-stratify unruptured
aneurysms for treatment. [3-5] Inflammation is related to Myeloperoxidase, a potent bactericidal substance
[6]
hemodynamic stress, but relying on only morphologic primarily housed in the granules of neutrophils, is
and hemodynamic factors alone does not account for present in the inflammatory environment. It is present
the role of inflammation in the pathobiology of cerebral in noninfectious inflammatory reactions such as those
aneurysms. accompanying atherosclerosis and vasculopathy. [12]
[9]
Several studies have demonstrated that inflammation Gounis et al. observed that increased myeloperoxidase
[13]
plays a key role in cerebral aneurysm formation and expression in aneurysm tissue harvested during surgery
rupture. [7-9] Specifically, the role of macrophages in the was associated with all ruptured aneurysms, as well
response to inflammatory mediators has been proposed as those unruptured aneurysms that were considered
as a mechanism for aneurysm rupture. [10,11] However, “high-risk” for rupture based on demographic and

anatomic characteristics. The same group has studied
Access this article online a paramagnetic agent (di-5-hydroxytryptamide
Quick Response Code: of gadopentetate dimeglumine) that highlights the
Website: presence of myeloperoxidase in animal models of
www.nnjournal.net
general vascular disease. [14] While no human studies

DOI: of this magnetic resonance contrast agent have been
10.4103/2347-8659.153970 performed, this represents a promising agent in the
noninvasive detection of aneurysmal inflammation.

Corresponding Author: Dr. Felipe C. Albuquerque, C/o Neuroscience Publications, Barrow Neurological Institute,
St. Joseph’s Hospital and Medical Center, 350 W. Thomas Road, Phoenix, AZ 85013, USA. E‑mail: neuropub@dignityhealth.org

Neuroimmunol Neuroinflammation | Volume 2 | Issue 2 | April 15, 2015 51