Navigated MRI-guided liver biopsies in a closed-bore scanner: experience in 52 patients

Abstract

ObjectivesTo evaluate clinical effectiveness and diagnostic efficiency of a navigation device for MR-guided biopsies of focal liver lesions in a closed-bore scanner.MethodsIn 52 patients, 55 biopsies were performed. An add-on MR navigation system with optical instrument tracking was used for image guidance and biopsy device insertion outside the bore. Fast control imaging allowed visualization of the true needle position at any time. The biopsy workflow and procedure duration were recorded. Histological analysis and clinical course/outcome were used to calculate sensitivity, specificity and diagnostic accuracy.ResultsFifty-four of 55 liver biopsies were performed successfully with the system. No major and four minor complications occurred. Mean tumour size was 23 ± 14 mm and the skin-to-target length ranged from 22 to 177 mm. In 39 cases, access path was double oblique. Sensitivity, specificity and diagnostic accuracy were 88 %, 100 % and 92 %, respectively. The mean procedure time was 51 ± 12 min, whereas the puncture itself lasted 16 ± 6 min. On average, four control scans were taken.ConclusionsUsing this navigation device, biopsies of poorly visible and difficult accessible liver lesions could be performed safely and reliably in a closed-bore MRI scanner. The system can be easily implemented in clinical routine workflow.Key Points• Targeted liver biopsies could be reliably performed in a closed-bore MRI.• The navigation system allows for image guidance outside of the scanner bore.• Assisted MRI-guided biopsies are helpful for focal lesions with a difficult access.• Successful integration of the method in clinical workflow was shown.• Subsequent system installation in an existing MRI environment is feasible.

Robot‐assistant for MRI‐guided liver ablation: A pilot study

“…23 The robot-assisted needle insertion was successfully completed on two patients, one of which required a double oblique insertion. Previous clinical studies 5,27 suggested that double oblique insertions are particularly difficult to map mentally and can therefore require several attempts. The discrepancy between calculated and actual needle tip position was attributed to needle bending due to tissue inhomogeneity, and to tissue shifts due to organ movement.…”

“…The lesion size and, for the first two patients, the insertion depth are within the range defined in previous clinical studies. 5 Notably, the presence of the robot did not visibly affect the MR images. Finally, the laser ablation procedure was successfully completed in all three cases without complications.…”

“…The inverse kinematics is initially solved for the specified target point P ′ and the insertion directionv 5 . In case α, β are outside the range Eq.…”

“…2 Conversely, needle insertions in closed-bore scanners entail repeatedly moving the patient in and out of the bore because of the space constraints. 5 Additionally, conventional freehand needle insertions require considerable training and 2D to 3D extrapolation skills. Consequently, several insertion attempts may be necessary.…”

Lung and Abdominal Biopsies in the Age of Precision Medicine

“…52,53 In addition, different pulse sequences can be used to distinguish pathology and identify the most relevant portions of a lesion to biopsy (i.e., areas of necrosis on T2-weighted images). 54 This approach has been shown not only to be feasible, but also to have excellent safety and diagnostic yield in the brain, 44,[55][56][57] percutaneous interventions in the chest, abdomen, and pelvis, [58][59][60][61][62] and even ablative therapy. 63,64 Currently, as this technology is brought to market, these robot functionalities and techniques are being refined and incorporated into workflow.…”