Moyamoya Disease: Impact of Evolving Different Management Approaches to Improve Overall Neurologic Outcome

Intracranial collateral circulation and its role in neurovascular pathology

Background

Collateral circulation is a vascular network which maintains the blood flow after the partial blockage of primary vascular pathways. This acts as potential vascular supplementary system and plays important role in the cerebral ischemia.

Main body

Collateral circulation has implications in the management especially related to cerebral endovascular treatment and thrombolytic therapy. It is considered as subsidiary network of vascular channels, which is highly variable. Insufficient arterial supply is due to the hemodynamic compromise because of thromboembolism. Apart from the collaterals, there is additional existence of a group of vessels known as venous collaterals. Their function is variable and they contribute to the augmentation of venous drainage in venous ischemias. Various pharmacological interventions are used to modulate the collaterals, these can prove to be a complementary alternative to the invasive intracerebral interventions.

Conclusions

The aim of this review article is to highlight the importance of cerebral collateral circulation and to discuss the various available pharmacological alternatives available and their current relevance in the management of various neurovascular pathologies.

Quantification of intracranial arterial stenotic degree evaluated by high-resolution vessel wall imaging and time-of-flight MR angiography: reproducibility, and diagnostic agreement with DSA

OBJECTIVES

The purpose of this study was to compare the reproducibility and diagnostic agreement of high-resolution vessel wall imaging (HR-VWI) and time-of-flight magnetic resonance angiography (TOF-MRA) with digital subtraction angiography (DSA) to evaluate intracranial arterial stenosis.

METHODS

We retrospectively enrolled patients who underwent HR-VWI and TOF-MRA with suspected intracranial artery disease and had DSA results from our institutional imaging database. Two neuroradiologists separately and independently evaluated anonymous image data for the stenotic lesions. DSA was analyzed by two neurointerventionalists and it served as a standard criterion. The reproducibility of these two MR techniques was determined by the intraclass correlation coefficients (ICCs). The diagnostic agreement to DSA was assessed by the concordance correlation coefficients (CCCs).

RESULTS

A total of 246 lesions from 106 individuals were analyzed for stenotic degrees. The total intra-observer and inter-observer reproducibility of HR-VWI was excellent for identifying stenosis and better than of TOF-MRA. The overall concordance of HR-VWI with DSA was excellent with CCC = 0.932, whereas TOF-MRA was 0.694. In addition, HR-VWI could provide additional vessel wall information.

CONCLUSIONS

HR-VWI has more advantages over TOF-MRA, such as better reproducibilities and diagnostic agreements with DSA to analyze intracranial arterial stenosis. It provides additional information that helps in clinical diagnosis and management.

KEY POINTS

• High-resolution vessel wall imaging can assess intracranial arterial stenosis with a better reproducibility than TOF-MRA and has a higher diagnostic agreement with DSA. • High-resolution vessel wall imaging had a higher diagnostic agreement with DSA compared with TOF-MRA. • Apart from evaluating vascular stenosis, HR-VWI provided additional vessel wall information to help in clinical diagnosis.