Clinical condition—Low back pain

	MRI (lumbar spine, without contrast)	MRI (lumbar spine, without and with contrast)	CT (lumbar spine, without contrast)	CT (lumbar spine, without and with contrast)	X-ray (lumbar spine)	CT Myelogram	Myelogram	Bone scan
Uncomplicated, no red flags	2	2	2	N/A	2	2^a	2^a	2
Low velocity trauma, osteoporosis, and/or age >70	8	3	6^b	N/A	6	1^a	1^a	4
Suspicion of cancer, infection or immunosuppression	8	7	4	N/A	5	2^a	2^a	5
Radiculopathy	8	5^b	5	N/A	3	5^a,^b	2^a	2
Prior lumbar surgery	6	8^c	6^b	N/A	5^d	5^a	2^a	5
Cauda equina syndrome	9^e	8^e	N/A	4^b,^e	3	6^a,^b	2^a	2

Note:—Appropriateness criteria scale from 1 to 9, 1 = least appropriate, 9 = most appropriate;
a , indicates CT and myelography often combined;
b , useful if MRI contraindicated or nondiagnostic;
c , differentiate disk versus scar;
d , flex/extension may be useful;
e , use of contrast depends on clinical circumstances