Arterial Spin Labelling: Initial Experience, Clinical Impact and Difficulties

Abstract

Arterial spin labelling (ASL) is a MR perfusion technique that uses protons from water molecules of the arterial blood as an endogenous tracer. It is fast, non-invasive and does not require gadolinium administration. Due to the increasing robustness of the results, it is becoming an important clinical tool. In this article we present our initial experience with ASL, highlighting some technical aspects, the main clinical applications, some achieved results and most important difficulties.

Methods: Review of the examinations performed during eight months, using a pulsating ASL technique in a 3T machine. Perfusion maps were evaluated qualitatively.

Results: The most frequent clinical applications were epilepsy, neurodegenerative disorders and tumours. Although perfusion data from ASL had never been crucial for diagnosis, it still provided substantial information. We highlight two epileptic patients who had had recent seizures, in which ASL depicted distinct post-ictal hyperperfusion areas (with the results being confirmed by SPECT studies). The impact was also remarkable in patients with neurodegenerative disorders in which ASL depicted hypoperfusion areas, typical of each nosological entity. The main difficulties were related to the lack of quantitative evaluation and to the clinical interpretation of the results obtained.

Conclusion: ASL perfusion studies have a great potential in several clinical conditions. In this article we show that, with a fast acquisition and easy post-processing, it can integrate routine MRI examinations.