Low-dose multi-detector computed tomography for periradicular infiltrations at the cervical and lumbar spine

Abstract

Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p < 0.01; reduction of 33.5%). Image noise was comparable between LD and SD scans (13.13 ± 3.66 HU vs. 13.37 ± 4.08 HU; p = 0.85). Overall image quality was scored as good to very good with only minimal artifacts according to both readers, and determination of the nerve root was possible in almost all patients (LD vs. SD: p > 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.

Impact of radiation dose reduction and iterative image reconstruction on CT-guided spine biopsies

“…From this point of view, pre-biopsy imaging should be carefully reviewed and when possible focused on the definite region of biopsy, together with an optimized radiation dose. This approach is similar to a recent study investigating LD protocols for CT-guided periradicular infiltrations 33 . However, biopsies use hardware for puncture of the target region with comparatively large calibers (e.g., potential risk for more pronounced artifacts especially with LD protocols) that often need to be inserted deeper into tissue (e.g., close to the nerve root in periradicular infiltrations versus biopsies of vertebral bone), making distinct investigations for biopsies necessary in the light of patient safety and sufficient image quality.…”

Computed Tomography of the Spine

“…Excluding LD simulations, reported dose reductions ranged from 34% in 204 PRI patients [ 60 ] up to 93% in 183 cervical PRI patients [ 59 ] and 94% in 65 sacroiliac joint injection patients [ 55 ]. The use of LD protocols did not meaningfully affect the rate of complications [ 54 , 55 , 58 ] or patient-reported pain [ 53 , 59 , 68 ].…”

“…After implementation of an LD protocol with tube currents reduced from 40 mA to 20–30 mA, a study in 204 patients observed no relevant difference in IQ or nerve root determination. The reported dose reduction of 34% did not affect the confidence for both planning and performing PRIs at the cervical and lumbosacral spine [ 60 ].…”

“…Dose reductions were explicitly reported in 32 studies and retrospectively calculated from provided dose values in 5 studies, 2 studies reported dose reductions based on only CTDIvol [33,50], 10 studies on only DLP [51][52][53][54][55][56][57][58][59][60], 7 studies on only E [34,[61][62][63][64][65][66], 5 studies on both CTDIvol and DLP [35][36][37][38][39], 1 study on both CTDIvol and E [67], and 1 study on both DLP and E [68]. Dose reduction was retrospectively calculated in one study based on only DLP [69], in two studies on only E [53,70], and in another two studies on both CTDIvol and DLP [71,72].…”