Fusion imaging guidance may be an interesting solution when the interventional radiologist needs information belonging to different imaging volume. Virtual navigation systems in pre-operative 3D MRI or CT datasets bring the possibility to improve real-time lesion targeting. These systems can be used alone with optical or electromagnetic tracking platforms, or associated with US guidance.1 For this last solution, the operator has the opportunity to navigate in the CT or MRI 3D volume loaded when performing the US exploration. Hence fusion systems bring the possibility to...

Informed consent was signed by all patients who accepted to participate to this study, validated by the clinical research center of our institution. Eight needles in eight patients treated by radiofrequency thermal ablation (RFA) for hepatic tumors were evaluated. The insertion of a 22G spinal needle in the liver was performed using the CT–ultrasound fusion imaging system (Toshiba, TUS-A500, SmartFusion application). The aim was to put the needle just at the contact of the lesion, without penetrating it. Shortly, a magnetic position sensor was attached...

Absolute value of mean differences of the three coordinates (|x’-x|,|y’-y|,|z’-z|, mean±SD) were 2.7±2, 6.2±4.6 and 5.2±4.7 mm for the distal (D) point. Results were 2.5±2.5, 5.7±2.9 and 5.6±4.7 mm for the proximal (P) point. Global mean difference was 4.7mm±4.1mm and 4.6mm±3.7mm for D and P respectively. Those differences were compared to 7 mm by using gamma distributions and bayesian methods. X coordinates could be considered less than 7 with probabibility close to 1. Y and Z were not considered bigger or smaller (Prob > 7...

We found that CT–ultrasound fusion allows navigation in both ultrasound and pre-operatively acquired CT volume with a mean difference of coordinates of 4.7mm±4.1mm and 4.6mm±3.7mm for the tip of the needle and a needle point located 3 cm proximally respectively. This error is acceptable in comparison to the mean registration error of 3.0 mm reported in a in vitro study.5 This error has to be reevaluated with the insertion of the final needle that will further modify the anatomy and when the prior MRI or...

Authors do not have any conflict of interest. Toshiba gave the TUS-A500 for evaluation.

1.1.Krucker J, Xu S, Venkatesan A, et al. Clinical utility of real-time fusion guidance for biopsy and ablation. J Vasc Interv Radiol 2011; 22:515-24. 2.2.Hirooka M, Iuchi H, Kumagi T, et al. Virtual sonographic radiofrequency ablation of hepatocellular carcinoma visualized on CT but not on conventional sonography. AJR Am J Roentgenol 2006; 186:S255-60. 3.3.Nakai M, Sato M, Sahara S, et al. Radiofrequency ablation assisted by real-time virtual sonography and CT for hepatocellular carcinoma undetectable by conventional sonography. Cardiovasc Intervent Radiol 2009; 32:62-9. 4.4.Lee MW, Rhim...