Clinical data, operative summary, and signal intensity changes with time after contrast medium injection for patients who received ionic and nonionic contrast medium

Patient No.	Age (yr)	History	Reoperation Findings	Contrast Medium	Signal Intensity
					Baseline		5 min		20 min
					Scar	Disk	Scar	Disk	Scar	Disk
1	47	Two previous excisions of herniated disk at L4–L5, recurrent left leg pain	Not offered	Gadopentetate	43.1	48.3	69.9	40.1	93.4	48.4
				Gadodiamide	33.9	34.6	87.7	58.0	89.4	47.1

2	43	L3–L4 discectomy, recurrent pain	At laminectomy, large scar and fragment containing end plate and bone	Gadopentetate	42.7	45.4	88.6	33.5	76.1	44.7
				Gadodiamide	28.6	36.6	103.6	47.7	86.0	69.0
3	37	5 years previously, laminectomy and discectomy at L4–L5, pain recurred	At laminectomy, large fragment	Gadopentetate	22.9	33.1	45.4	33.1	52.8	34.8
				Gadodiamide	33.8	24.8	72.9	33.8	90.5	32.8
4	47	Pain in lower back, previous L4–L5 laminectomy and discectomy	Lost to follow-up	Gadopentetate	68.9	60.0	99.6	61.8	103.5	68.8
				Gadodiamide	46.2	40.0	80.3	52.0	78.3	56.0
5	46	Previous discectomies L4–L5 and L5–S1, low back and left lower extremity pain	Not offered	Gadopentetate	25.9	27.1	47.5	32.2	42.7	30.5
				Gadodiamide	23.5	22.8	46.0	25.7	47.0	39.3
6	48	Microdiscectomy L5–S1 1 year previously, recurrence of pain	Not offered	Gadopentetate	35.0	32.0	59.0	45.0	68.0	54.0
				Gadodiamide	35.0	32.0	91.0	54.0	80.0	57.0
7	39	Discectomy L4–L5 in 1998, revision in 2000, gradually worsening right buttock and thigh pain for 6 months	Anterior discectomy	Gadopentetate	37.9	53.3	94.7	65.7	90.8	72.4
				Gadodiamide	33.7	43.7	76.9	49.3	80.5	51.5
8	42	Microdiscectomy L4–L5, acute onset of pain radiating into left leg	At laminectomy, large herniation	Gadopentetate	24.0	21.0	67.0	28.0
				Gadodiamide	18.0	22.0	87.0	40.0