Feasibility of tracked ultrasound registration for pelvic–abdominal tumor navigation: a patient study

• Published in: International journal for computer assisted radiology and surgery Vol. 18; no. 9; pp. 1725 - 1734
• Main Authors: Hiep, M. A. J., Heerink, W. J., Groen, H. C., Ruers, T. J. M.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2023; Springer Nature B.V
• Subjects: Abdomen; Algorithms; Computed tomography; Computer Imaging; Computer Science; Feasibility; Health Informatics; Image segmentation; Imaging; Medicine; Medicine & Public Health; Optimization; Original Article; Pattern Recognition and Graphics; Pelvis; Radiation effects; Radiology; Registration; Surgery; Ultrasonic imaging; Vision; Workflow; Pelvic malignancies; Bone; Ultrasound; Registration; Surgical navigation; Electromagnetic tracking
• DOI: 10.1007/s11548-023-02937-8
• EISSN: 1861-6429
• ISSN: 1861-6429; 1861-6410

Purpose
Surgical navigation techniques can guide surgeons in localizing pelvic–abdominal malignancies. For abdominal navigation, accurate patient registration is crucial and is generally performed using an intra-operative cone-beam CT (CBCT). However, this method causes 15-min surgical preparation workflow interruption and radiation exposure, and more importantly, it cannot be repeated during surgery to compensate for large patient movement. As an alternative, the accuracy and feasibility of tracked ultrasound (US) registration are assessed in this patient study.
Methods
Patients scheduled for surgical navigation during laparotomy of pelvic–abdominal malignancies were prospectively included. In the operating room, two percutaneous tracked US scans of the pelvic bone were acquired: one in supine and one in Trendelenburg patient position. Postoperatively, the bone surface was semiautomatically segmented from US images and registered to the bone surface on the preoperative CT scan. The US registration accuracy was computed using the CBCT registration as a reference and acquisition times were compared. Additionally, both US measurements were compared to quantify the registration error caused by patient movement into Trendelenburg.
Results
In total, 18 patients were included and analyzed. US registration resulted in a mean surface registration error of 1.2 ± 0.2 mm and a mean target registration error of 3.3 ± 1.4 mm. US acquisitions were 4 × faster than the CBCT scans (two-sample
t
-test
P
 < 0.05) and could even be performed during standard patient preparation before skin incision. Patient repositioning in Trendelenburg caused a mean target registration error of 7.7 ± 3.3 mm, mainly in cranial direction.
Conclusion
US registration based on the pelvic bone is accurate, fast and feasible for surgical navigation. Further optimization of the bone segmentation algorithm will allow for real-time registration in the clinical workflow. In the end, this would allow intra-operative US registration to correct for large patient movement.
Trial registration:
This study is registered in ClinicalTrials.gov (NCT05637359).