Clinical condition: focal neurologic deficit*

	MRI Head	CT Head without Contrast	MRA Head and Neck	CT Head without and with Contrast	CTA Head and Neck	MRI Spectroscopy Head	Arteriography Cervicocerebral	FDG-PET Head
Multiple focal neurologic deficits^‡‡	8^†^‡	7^§	6^‖	6^¶	6^‖	4^#	3^**	2
Single focal neurologic deficit, sudden onset, stable, or incompletely resolving^‡‡	8^‡^††	8^††	7	5^¶	7	4	3^**	2
Single neurologic deficit, sudden onset, progressive^‡‡	8^‡^††	8^††	7	6^¶	7	4	3^**	1
Single focal neurologic deficit, completely resolving^‡‡	8^‡^††	8^††	7	6^¶	7	3	3^**	1
Unexplained acute confusion or altered level of consciousness^‡‡	8^‡^††	8^††	6^‖	5^¶	6^‖	3	2	3

Note:—MRI indicates MR imaging; MRA, MR angiography; CTA, CT angiography; FDG-PET, fluorodeoxyglucose–positron-emission tomography.
* Appropriateness criteria scale from 1 to 9, 1 = least appropriate, 9 = most appropriate.
† Consider increased contrast dose for problem solving in selected cases.
‡ Include diffusion-weighted imaging.
§ Acute screening.
‖ For suspected vascular abnormality.
¶ If MRI is unavailable or contraindicated, consider CT perfusion.
# For selected cases.
** For problem solving.
†† Both CT and MR may be necessary. CT screens for suspected hemorrhage in the acute setting and MR screens for infarction and masses.
‡‡ Other imaging modalities considered: MRI functional head, received rating of 3; single-photon emission CT head, received rating of 3; X-ray head, received rating of 1.