Evaluation of a robotic system for irreversible electroporation (IRE) of malignant liver tumors: initial results

OBJECTIVE

Comparison of conventional CT-guided manual irreversible electroporation (IRE) of malignant liver tumors and a robot-assisted approach regarding procedural accuracy, intervention time, dose, complications, and treatment success.

METHODS

A retrospective single-center analysis of 40 cases of irreversible electroporation of malignant liver tumors in 35 patients (6 females, 29 males, average age 60.3 years). Nineteen of these ablation procedures were performed manually and 21 with robotic assistance. A follow-up (ultrasound, CT, and MRI) was performed after 6 weeks in all patients.

RESULTS

The time from the planning CT scan to the start of the ablation as well as the dose-length product were significantly lower under robotic assistance (63.5 vs. 87.4 min, [Formula: see text]; 2132 vs. 4714 mGy cm, [Formula: see text]). The procedural accuracy, measured as the deviation of the IRE probes with respect to a defined reference probe, was significantly higher using robotic guidance (2.2 vs. 3.1 mm, [Formula: see text]). There were no complications. There was one incomplete ablation in the manual group.

CONCLUSION

Robotic assistance for IRE of liver tumors allows for faster procedure times with higher accuracy while reducing radiation dose as compared to the manual placement of IRE probes.

Percutaneous irreversible electroporation (IRE) of prostate cancer: Contrast-enhanced ultrasound (CEUS) findings

PURPOSE

To evaluate the use of contrast-enhanced ultrasound (CEUS) after irreversible electroporation (IRE) of prostatic cancer tissue to assess the ablation status by depicting microvascularisation in the ablation area.

MATERIALS AND METHODS

Retrospective evaluation of CEUS of 13 patients (mean age: 61.4 ± 7.5 years) with histologically confirmed prostatic cancer who underwent percutaneous IRE. In the course of clinical routine, the tumor lesions were documented before, immediately after, and 1 day after the ablationusing color-coded transabdominal and transrectal CEUS. The obtained image data (DICOM loops and images) were subsequently evaluated by 2 experienced radiologists and assessed with regard to micro vascularisation by means of a 5-point scale.

RESULTS

CEUS images showed significantly reduced microcirculation of the lesions (mean 0.9 ± 0.6 cm (0.5-1.5 cm) after IRE. Microcirculation was reduced from 2.15 ± 0.56 prior to ablation to 0.65 ± 0.63 (p <  0.001) immediately after the ablation and to 0.27 ± 0.44 one day after IRE (p <  0.001).

CONCLUSION

This study showed rapid and significant reduction of the microcirculation in the ablation area afterpercutaneous IRE of prostatic cancer tissue.

Robot-assisted microwave thermoablation of liver tumors: a single-center experience

PURPOSE

To evaluate and compare the needle placement accuracy, patient dose, procedural time, complication rate and ablation success of microwave thermoablation using a novel robotic guidance approach and a manual approach.

METHODS

We performed a retrospective single-center evaluation of 64 microwave thermoablations of liver tumors in 46 patients (10 female, 36 male, mean age 66 years) between June 2014 and February 2015. Thirty ablations were carried out with manual guidance, while 34 ablations were performed using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and MRI) was performed on all patients.

RESULTS

The total procedure time and dose-length product were significantly reduced under robotic guidance (18.3 vs. 21.7 min, [Formula: see text]; 2216 vs. 2881 mGy[Formula: see text]cm, [Formula: see text]). The position of the percutaneous needle was more accurate using robotic guidance (needle deviation 1.6 vs. 3.3 mm, [Formula: see text]). There was no significant difference between both groups regarding the complication rate and the ablation success.

CONCLUSION

Robotic assistance for liver tumor ablation reduces patient dose and allows for fast positioning of the microwave applicator with high accuracy. The complication rate and ablation success of percutaneous microwave thermoablation of malignant liver tumors using either CT fluoroscopy or robotic guidance for needle positioning showed no significant differences in the 6-week follow-up.

Combination of rotational atherothrombectomy and Paclitaxel-coated angioplasty for femoropopliteal occlusion

OBJECTIVE

The rotational atherothrombectomy with Straub Rotarex^® is a safe and efficient treatment of acute/subactute vascular occlusions. The purpose of this study was to evaluate the benefit of paclitaxel-coated angioplasty after rotational atherothrombectomy over an observation period of six months.

MATERIALS AND METHODS

Overall, 29 patients were treated with the Rotarex catheter in combination with paclitaxel-coated angioplasty. All patients had acute/subacute and chronic occlusions of the superficial femoral artery (SFA) and/or popliteal arteries. The ankle-brachial index (ABI) was detected before the intervention, after the procedure, and after six months. Also clinical examination and ultrasound scans were done in the observation period.

RESULTS

There were no technical failures. The ABI shows a significant increase from 0.52 ± 0.17 to 0.91 ± 0.25 in the follow-up. By ultrasound examination, there were found two (6.9%) restenoses during the follow-up. There was one dissection during the intervention (3.5%).

CONCLUSION

The rotational atherothrombectomy in combination with paclitaxel-coated angioplasty might be an effective and safe method with a promising low rate of restenosis at six months.

Multivariable analysis of clinical influence factors on liver enhancement of Gd-EOB-DTPA-enhanced 3T MRI

PURPOSE

The purpose of this study was to identify clinical factors influencing Gd-EOB-DTPA liver uptake in patients with healthy liver parenchyma.

MATERIALS AND METHODS

A total of 124 patients underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3 T. T1-weighted volume interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 minutes after contrast injection. The relative enhancement (RE) between plain and contrast-enhanced signal intensity was calculated. Simple and multiple linear regression analyses were performed to evaluate clinical factors influencing the relative enhancement. Patients were subdivided into three groups according to their relative liver enhancement (HRE, RE ≥ 100 %; MRE, 100 % > RE > 50 %; NRE, RE ≤ 50 %) and were analyzed according to the relevant risk factors.

RESULTS

Simple regression analyses revealed patient age, transaminases (AST, ALT, GGT), liver, spleen and delta-liver volume (the difference between the volumetrically measured liver volume and the estimated liver volume based on body weight) as significant factors influencing relative enhancement. In the multiple analysis the transaminase AST, spleen and delta liver volume remained significant factors influencing relative enhancement. Delta liver volume showed a significant difference between all analyzed groups.

CONCLUSION

Liver enhancement in the hepatobiliary phase depends on a variety of factors. Body weight-adapted administration of Gd-EOB-DTPA may lead to inadequate liver enhancement after 20 minutes especially when the actual liver volume differs from the expected volume.

KEY POINTS

• Differences between actual and expected liver volume can cause inadequate liver enhancement after 20 min. • A liver volume-adapted dose of Gd-EOB-DTPA may help to improve liver enhancement.