Table 4. Results of various studies measuring mean MCA diameters using direct vision in cadaver studies, using MRA, angiography, and Doppler.

Measurement modality	Mean MCA diameter (mm)	Number of subjects	Notes
Cadaver	2.5–4 mm (mean=3.35 mm) (Pai et al, 2005)	5
MRA (all 1.5 T)	2.9 mm (Serrador et al, 2000)	12
	2.73 mm (Schreiber et al, 2000)	8
	2.23 mm (Tarasow et al, 2007)	36
	2.95 mm (Hansen et al, 2007)	12
	3.4 mm (Valdueza et al, 1997)	6
Angiography	2.38 mm (Tarasow et al, 2007)	36
Power Doppler
Proximal MCA	5.2 mm	17	Subjects suspected of
Distal MCA	4.3 mm (Muller et al, 2000)		having vasospasm
TCCS
Proximal MCA	5.9 mm	17	Subjects suspected of
Distal MCA	4.9 mm (Muller et al, 2000)		having vasospasm

MCA, middle cerebral artery; MRA, magnetic resonance angiography; TCCS, transcranial color-coded sonography.

The differences between MRA and Doppler-measured diameters are similar to ours.