SPECT

In brief: SPECT is a nuclear medicine study that maps relative cerebral perfusion using an injected radiotracer.

Some protocols compare baseline perfusion with a vasodilatory challenge to estimate cerebrovascular reserve. Results can help identify territories with limited ability to increase flow and may contribute to treatment decisions.

Use in moyamoya disease

European guidance supports hemodynamic assessment during diagnostic workup, while recognizing that methods and thresholds are not standardized across centers. [1]

Clinical detail

Spatial resolution is lower than MRI, and quantitative comparison depends on tracer, timing, processing, challenge protocol, and reference region.

A result should be read as one part of a broader hemodynamic assessment rather than as a stand-alone diagnosis or automatic indication for surgery.