[Periradicular infiltration therapy : Clinical indications, technique and results]

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

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.

[CT-guided pain management of specific low back pain : Disc impairment vs. osseous degeneration]

Hintergrund

Rückenschmerz ist häufig und führt den Patienten sowohl zur Diagnostik als auch in bestimmten Fällen für eine Therapie zum Radiologen.

Fragestellung

Die vorliegende Untersuchung vergleicht die schmerzreduzierende Wirkung der mikroinvasiven Computertomographie(CT)-gesteuerten Schmerztherapie bei diskogenem und spondylarthrotisch bedingtem spezifischem Rückenschmerz.

Material und Methode

Über einen Zeitraum von 3,3 Jahren wurden 239 Patienten in die Untersuchung eingeschlossen, bei denen 686 CT-gesteuerte periradikuläre Therapien (PRT) und 264 CT-gesteuerte Facettengelenktherapien (FAC) durchgeführt und beurteilt wurden. Bei allen Patienten wurde vor der Intervention, im Verlauf und am Ende der Schmerzscore mittels visueller analoger Schmerzskala (VAS) bestimmt. Abschließend wurde der Behandlungserfolg in Abhängigkeit von der durchgeführten Behandlungsart und den morphologisch vorliegenden Veränderungen korreliert.

Ergebnisse

In beiden Gruppen zeigte sich unter der Behandlung eine gute Beschwerdebesserung (74 % bei PRT-Patienten und 60 % bei FAC-Patienten). Die Patienten, bei denen eine PRT durchgeführt wurde, zeigten durchschnittlich eine Verbesserung des Schmerzscores von 3,1, bei Patienten mit durchgeführter FAC von 2,1. Die Wirksamkeit der FAC zeigte eine Abhängigkeit der Wirksamkeit vom Grad der vorhandenen degenerativen Veränderungen. Je ausgeprägter die nachgewiesene Degeneration im behandelten Segment war, desto mehr Interventionen waren für ein gutes Therapieansprechen notwendig.

Schlussfolgerung

Die CT-gesteuerte PRT und FAC führen beide zu einer guten Reduktion der Beschwerdesymptomatik. Im Vergleich erzielte die PRT eine signifikant höhere Schmerzreduktion als die FAC.

Periradicular infiltration of the lumbar spine: testing the robustness of an interventional ultra-low-dose protocol at different body mass index levels

Background Computed tomography (CT)-guided periradicular infiltration remains a frequent interventional procedure for treatment of low back pain. Purpose To present an interventional ultra-low-dose protocol for CT-guided periradicular infiltration therapy and assess its application at different body mass index (BMI) levels. Material and Methods Over a period of 14 months, 79 patients underwent 183 CT-guided interventions for single-site lumbar periradicular therapy using an ultra-low-dose protocol with a basic setup of 100 kV and 5 mAs. Procedures were performed via intermittent fluoroscopy. A retrospective review was performed to analyze the parameters tube current and tube voltage, dose-length product, and BMI. Results The interventional ultra-low-dose protocol allowed safe treatment of 91.1% of the patients without a need for adapting the protocol. In seven patients with a higher BMI (range, 31-38 kg/m²; mean, 34 kg/m²), the tube current had to be increased to retain sufficient image quality. Only patients with a BMI of 30 and higher showed a significant correlation between BMI and dose-length product ( P value = 0.02), resulting in a slightly increased dose ( P value = 0.002). Conclusion The protocol presented for the interventional part of CT-guided periradicular infiltration allows to safely treat patients with a median calculated effective dose of 0.045 mSv (converted from a dose-length-product of 2.26 mGy*cm). Patients with a BMI of 30 and higher required a higher calculated effective dose with just one patient slightly exceeding 0.1 mSv.

Ultra-low-dose periradicular infiltration of the lumbar spine: spot scanning and its potential for further dose reduction by replacing helical planning CT

PURPOSE

Computed tomography (CT)-guided periradicular infiltration has become an accepted procedure for treating radiculopathy-associated low back pain. The purpose of this study is to compare spot scanning and segmental helical planning CT in terms of dose reduction.

MATERIALS AND METHODS

Eighty-five patients underwent CT-guided single-site lumbar periradicular therapy. Prior imaging was not available for planning. Sixty-three patients were examined with a new dedicated spot scanning technique (group I), and twenty-two patients underwent conventional segmental planning CT examinations with helical image acquisition serving as controls (group II). Examinations were reviewed retrospectively for dose-length product (DLP) and number of acquisitions required for intervention. Pain reduction accomplished with the intervention was recorded for quality assurance.

RESULTS

Median DLP was 0.80 mGy cm for spot scanning versus 6.50 mGy cm for segmental planning CT. Thus, the contribution of the planning scan to the total interventional dose decreased from 73 to 25%. As a result, the total interventional dose was reduced significantly from a median DLP of 8.90 mGy cm to 3.20 mGy cm (-64%). Acquisitions required during the intervention had a median DLP of 2.40 mGy cm for group I and 2.35 mGy cm for group II, showing no significant difference. Median pain reduction in both groups was two points on the numeric rating scale.

CONCLUSION

Dedicated spot scanning for planning reduced the total median effective dose of the intervention by more than 64% without increasing the number of images required during the interventional procedure. Significant pain reduction was achieved with both approaches. Spot scanning is recommended for dose reduction.