[A new laser puncture guidance device for CT- and MRT-guided punctures of the trunk]

CT-guided biopsy of thoracic lesions with a novel wire-based needle guide device - initial experiences

BACKGROUND

Biopsies guided by computed tomography (CT) play an important role in clinical practice. A short duration, minimal radiation dose and complication rate are of particular interest. Purpose To evaluate the potential of a novel self-manufactured wire-based needle guide device for CT-guided thoracic biopsies with respect to radiation dose, intervention time and complication rate.

MATERIAL AND METHODS

Forty patients that underwent CT-guided biopsies of thoracic lesions were included in this study and assigned to two groups. Patients in group A (n = 20, mean age 69 ± 8.4 years) underwent biopsies with a novel wire-based needle guide device, while patients in group B (n = 20, mean age 68.4 ± 10.1 years) were biopsied without a needle guide device. The novel self-manufactured needle guide device consists of an iron/zinc wire modelled to a ring with a flexible arm and an eye at the end of the arm to stabilize the biopsy needle in the optimal position during intervention. Predefined parameters (radiation dose, number of acquired CT-slices, duration of intervention, complications) were compared between both groups.

RESULTS

Mean radiation dose (CTDIvol 192 mGy versus 541 mGy; P ≤ 0.001) and the number of acquired slices during intervention (n = 49 ± 33 vs. n = 126 ± 78; P ≤ 0.001) were significantly lower in group A compared with group B. Intervention time in group A (13.1 min) was significantly lower than in group B (18.5 min, P < 0.01). A pneumothorax as peri-interventional complication was observed less frequent after device assisted biopsies (n = 4 vs. n = 8, n.s.).

CONCLUSION

The novel wire-based needle guide device is a promising tool to facilitate CT-guided thoracic biopsies reducing radiation dose, intervention time, and related complications. Further studies are mandatory to confirm these initial results.

CT-guided intervention using a patient laser marker system

To prove the usefulness of a simple laser marker system (LMS) in target definition as well as examination procedure for CT-guided interventions, 130 cases of diagnostic biopsies and lumbal sympathectomies were compared. In 75 cases LMS and in 55 cases a simple crossgrid was used. Taking advantage of the LMS, the parameters of intervention (cutaneous location, length, and angle) can be planned, exactly demonstrated, and it is possible to check the needle position during the whole procedure. Thus, the number of necessary control scans decreased to 30%, and corrections of needle location were reduced to approximately 30%. Moreover, the average target deviation of the needle decreased below 5 mm in 50% of cases, and the duration of interventional procedure was reduced considerably. It can be concluded that LMSs are recommended in CT-guided interventions for quality assurance, dose reduction, and improvement of handling. It will be especially advantageous in cases of small target volume, oblique needle path, and tilted gantry.

Circular spirit level guidance system for CT- and MR-guided punctures

A circular spirit level guidance system was tested for control of CT- and MR-guided punctures. The device consists of a needle holder fixed to a ground plate and two protractors. This allows adjustment of the fixed needle according to the angulation of the supposed puncture path as measured on tomographic images. A circular spirit level is fixed to the needle and leveled. Now the needle can be removed from the needle holder; by leveling the circular spirit level during the puncture, the formerly adjusted angulation is achieved. The system was tested in vitro and in vivo (22 patients) under CT and MR guidance. The average needle deviation was measured to be 1.96 degrees in vitro and 2.51 degrees in vivo. This simple device allows accurate puncture under CT and MR guidance.