Article Figures & Data
Figures
- Fig 1.
Phantom study assessing needle visibility. A, Scout image from CT demonstrating the configuration of the phantom. The central chamber houses contrast and a 22-gauge needle. Axial cross-sectional images of the chamber are shown with various contrast dilutions: 50 mg/mL (B), 66 mg/mL (C), 100 mg/mL (D), 133 mg/mL (E), and 150 mg/mL (F).
- Fig 2.
Axial CTF images show representative examples of visibility scores on the basis of our 5-point scoring system. A, Score of +2. The contrast is too dense to visualize the location of the needle tip. B, Score of 0. The needle tip can be distinguished from the injected contrast; adequate soft tissue contrast is also provided. C, Score of −2. The injected contrast is too dilute to provide adequate soft tissue contrast.
- Fig 3.
Importance of precise needle placement in cervical epidural steroid injections. A, Axial CTF image obtained before contrast injection. B, Image obtained immediately after contrast injection shows transient filling of small vessels (arrows). No epidural spread is seen. C, Image obtained after advancing the needle <2 mm demonstrates foraminal epidural contrast spread, with no vascular filling. Note the close proximity of the needle tip to the vertebral artery (*). This case highlights the importance of accurate localization of the needle tip and the need to be able to make small but precise adjustments in needle position during epidural injections.
Tables
Too Concentrated Optimal Too Dilute Visibility score +2 +1 0 −1 −2 Needle tip Not visible Borderline Visible Visible Visible Soft tissue contrast Adequate Adequate Adequate Borderline Not acceptable Visibility Score −2 −1 0 +1 +2 Total scores (n = 120) n = 9 n = 10 n = 34 n = 25 n = 42 (2 readers) (7.5%) (8.3%) (28.3%) (20.8%) (35.0%) Iodine concentration 66 mg/mL (n = 34) n = 7 n = 5 n = 15 n = 6 n = 1 (20.6%) (14.7%) (44.1%) (17.6%) (2.9%) 100 mg/mL (n = 32) n = 2 n = 5 n = 9 n = 10 n = 6 (6.3%) (15.6%) (28.1%) (31.3%) (18.8%) 133 mg/mL (n = 26) n = 0 n = 0 n = 2 n = 3 n = 21 (0%) (0%) (7.7%) (11.5%) (80.8%) 150 mg/mL (n = 28) n = 0 n = 0 n = 8 n = 6 n = 14 (0%) (0%) (28.6%) (21.4%) (50.0%) Injection technique ILESI (n = 64) n = 0 n = 3 n = 14 n = 17 n = 30 (0%) (4.7%) (21.9%) (26.6%) (46.9%) TFESI (n = 56) n = 9 n = 7 n = 20 n = 8 n = 12 (16.1%) (12.5%) (35.7%) (14.3%) (21.4%) - Table 3:
Comparison of visibility scores on the basis of combined iodine concentration and injection technique
Iodine Concentration + Injection Technique P Valuea (66 mg/mL and TFESI) versus (100 mg/mL and TFESI) .011 (66 mg/mL and ILESI) versus (100 mg/mL and ILESI) .016 (66 mg/mL and ILESI) versus (66 mg/mL and TFESI) .051 (100 mg/mL and ILESI) versus (100 mg/mL and TFESI) .021 ↵a P values are based on results of generalized estimating equations test of difference contrast statements with the use of a Bonferroni-corrected significance threshold of 0.0083.
