MRI-guided and CT-guided cervical nerve root infiltration therapy: a cost comparison

Spine injections: the rationale for CT guidance

Back pain is one of the most common medical problems and is associated with high socioeconomic costs. Imaging-guided spinal injections are a minimally invasive method to evaluate where the back pain is originating from, and to treat patients with radicular pain or spinal stenosis with infiltration of corticosteroids. CT-guided spine injections are a safe procedure, characterized by precise needle placement, excellent visualization of the relevant anatomical structures, and low radiation exposure for the patient and the interventional radiologist. In this review article, the variety of applications of CT-guided injections (focused on nerve roots and epidural injections) and the optimal injection procedure as well as risks and side effects are discussed.

Artefact and ablation performance of an MR-conditional high-power microwave system in bovine livers: an ex vivo study

Background

We evaluated a magnetic resonance (MR)-conditional high-power microwave ablation system.

Methods

An exvivo 1.5-T evaluation was conducted by varying the sequence (T1-weighted volume interpolated breath-hold examination, T1w-VIBE; T1-weighted fast low-angle shot, T1w-FLASH; T2-weighted turbo spin-echo, T2w-TSE), applicator angulation to B₀ (A-to-B₀), slice orientation, and encoding direction. Tip location error (TLE) and artefact diameters were measured, and influence of imaging parameters was assessed with analysis of variance and post hoc testing. Twenty-four exvivo ablations were conducted in three bovine livers at 80 W and 120 W. Ablation durations were 5, 10, and 15 min. Ablation zones were compared for short-axis diameter (SAD), volume, and sphericity index (SI) with unpaired t test.

Results

The artefact pattern was similar for all sequences. The shaft artefact (4.4 ± 2.9 mm, mean ± standard deviation) was dependent on the sequence (p = 0.012) and the A-to-B₀ (p < 0.001); the largest shaft diameter was measured with T1w-FLASH (6.3 ± 3.4 mm) and with perpendicular A-to-B₀ (6.7 ± 2.4 mm). The tip artefact (1.6 ± 0.7 mm) was dependent on A-to-B₀ (p = 0.001); TLE was -2.6 ± 1.0 mm. Ablation results at the maximum setting (15 min, 120 W) were SAD = 42.0 ± 1.41 mm; volume = 56.78 ± 3.08 cm³, SI = 0.68 ± 0.05. In all ablations, SI ranged 0.68–0.75 with the smallest SI at 15 min and 120 W (p = 0.048).

Conclusion

The system produced sufficiently large ablation zones and the artefact was appropriate for MR-guided interventions.