Session report – The  teaching course on rare intracranial vasculopathies

The teaching course on rare intracranial vasculopathies aimed to shed light on three cerebrovascular conditions that are often underrecognized and insufficiently considered in routine clinical practice, namely moyamoya disease, primary angiitis of the central nervous system (PACNS), and intracranial dissection. This 90-minute session was chaired by Stefan Kiechl (Innsbruck, Austria) and Jori Ruuskanen (Turku, Finland) and was highly interactive, with active participation from the audience, reflecting the growing interest in these disorders, which, also thanks to recent advances in diagnostic tools, are receiving increasing clinical attention.

Moyamoya angiopathy

Dominique Herve (Paris, France) opened the session with an insightful lecture on Moyamoya disease, a rare intracranial vasculopathy characterized by progressive stenosis of the intracranial segments of the cerebral afferent arteries and by the formation of an intricate network of fragile collateral vessels resembling a “puff of smoke” (“moyamoya” in Japanese), ultimately leading to an increased risk of both ischemic and hemorrhagic stroke. The lecture covered all major aspects of the disease, from diagnosis to therapeutic options. Starting from epidemiology, it was shown that the incidence of moyamoya disease is markedly higher in Asian countries than in European and American populations. Moreover, both the clinical and radiological features of the disease vary according to geographic origin, with systemic manifestations and atypical angiographic patterns being more frequently observed in patients from Western countries. Particular attention was devoted to emerging tools for the assessment of chronic cerebral hypoperfusion in these patients, such as SPECT imaging with a 99mTc tracer, which can rapidly identify patients who may benefit from early revascularization procedures. Regarding therapeutic options, although disease-modifying treatments are still unavailable, several surgical approaches capable of altering the natural history of the disease were discussed. In particular, according to the ESO guidelines by Bersano et al., revascularization procedures may be considered in patients presenting with ischemic or hemorrhagic manifestations in the presence of markers of cerebral hemodynamic impairment, as well as in patients with cerebral hemodynamic impairment associated with choroidal collaterals.

Primary Angiitis of the Central Nervous System (PACNS)

Next, Marialuisa Zedde (Reggio Emilia, Italy) delivered a lecture on primary angiitis of the central nervous system (PACNS), a highly complex disorder that remains challenging to recognize because of its broad spectrum of differential diagnoses. Particular emphasis was placed on the diagnostic difficulties posed by this rare condition. It was highlighted that the effective implementation of diagnostic and therapeutic recommendations requires a multidisciplinary approach involving vascular neurologists and neuroradiologists with specific expertise in PACNS and its mimics. Several diagnostic tools currently available for the evaluation of PACNS were discussed, and the recommendations provided in the latest ESO guidelines by Zedde et al. were illustrated. In particular, although brain MRI is abnormal in approximately 93% of patients, radiological findings are often nonspecific. Likewise, cerebrospinal fluid analysis, while mainly recommended to exclude alternative diagnoses, frequently yields either normal or nonspecific results in patients with PACNS. Considerable attention was devoted to the role of vascular imaging. Digital subtraction angiography (DSA) was presented as the current gold standard, given that MRA and CTA may fail to detect subtle abnormalities affecting distal vessels. Vessel wall imaging (VWI) was also discussed as a promising emerging technique; however, its current clinical application remains limited by insufficient pathological validation and by the difficulty in interpreting persistent vessel wall enhancement, which may remain detectable even after clinical resolution.

Intracranial Dissections
The final lecture, delivered by Vasileios-Arsenios Lioutas (Boston, United States), focused on intracranial dissections, with particular emphasis on the unique anatomical vulnerability of intracranial arteries. It was explained how these vessels are more prone to rupture and subarachnoid hemorrhage than extracranial arteries because of the absence of an external elastic lamina and the presence of a thinner tunica media. From a clinical perspective, intracranial dissections may present with either ischemic or hemorrhagic phenotypes, most commonly subarachnoid hemorrhage. Interestingly, clinical manifestations appear to vary according to the vascular territory involved, with ischemic presentations being more frequently associated with dissections of the anterior circulation and hemorrhagic manifestations predominating in posterior circulation involvement. Among the most important warning signs, the speaker highlighted the so-called “sentinel headache,” which may occur up to three days before a major cerebrovascular event and should therefore never be underestimated. Particular attention was also devoted to therapeutic management. Hemorrhagic presentations were described as true medical emergencies requiring immediate surgical or endovascular intervention, including both deconstructive and reconstructive techniques, in order to reduce the otherwise high mortality risk. Conversely, in non-hemorrhagic cases, antiplatelet therapy is generally preferred, although current evidence is largely extrapolated from studies on extracranial artery dissections. Intravenous thrombolysis, on the other hand, is usually discouraged because of the significantly increased risk of intracranial hemorrhage. Finally, long-term management was reported to rely on strict blood pressure control and serial vascular imaging, usually performed three to six months after the acute event, to assess vessel healing and the potential risk of recurrent dissection.