title: Workflow and intervention times of MR-guided focused ultrasound - Predicting the impact of new techniques.
abstract: Magnetic resonance guided focused ultrasound surgery (MRgFUS) has become an attractive, non-invasive treatment for benign and malignant tumours, and offers specific benefits for poorly accessible locations in the liver. However, the presence of the ribcage and the occurrence of liver motion due to respiration limit the applicability MRgFUS. Several techniques are being developed to address these issues or to decrease treatment times in other ways. However, the potential benefit of such improvements has not been quantified. In this research, the detailed workflow of current MRgFUS procedures was determined qualitatively and quantitatively by using observation studies on uterine MRgFUS interventions, and the bottlenecks in MRgFUS were identified. A validated simulation model based on discrete events simulation was developed to quantitatively predict the effect of new technological developments on the intervention duration of MRgFUS on the liver. During the observation studies, the duration and occurrence frequencies of all actions and decisions in the MRgFUS workflow were registered, as were the occurrence frequencies of motion detections and intervention halts. The observation results show that current MRgFUS uterine interventions take on average 213min. Organ motion was detected on average 2.9 times per intervention, of which on average 1.0 actually caused a need for rework. Nevertheless, these motion occurrences and the actions required to continue after their detection consumed on average 11% and up to 29% of the total intervention duration. The simulation results suggest that, depending on the motion occurrence frequency, the addition of new technology to automate currently manual MRgFUS tasks and motion compensation could potentially reduce the intervention durations by 98.4% (from 256h 5min to 4h 4min) in the case of 90% motion occurrence, and with 24% (from 5h 19min to 4h 2min) in the case of no motion. In conclusion, new tools were developed to predict how intervention durations will be affected by future workflow changes and by the introduction of new technology.
authors.affiliation: Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, TUD-3mE-BmechE, Mekelweg 2, 2628 CD Delft, The Netherlands. Electronic address: A.J.Loeve@tudelft.nl.
authors.forename: Arjo J
authors.initials: AJ
authors.lastname: Loeve
authors.affiliation: Fraunhofer MEVIS, Institute for Medical Image Computing, Universitätsallee 29, 28359 Bremen, Germany. Electronic address: jumana.al-issawi@gmx.de.
authors.forename: Jumana
authors.initials: J
authors.lastname: Al-Issawi
authors.affiliation: University of Dundee, College of Medicine, Institute for Medical Science and Technology, Division of Imaging and Technology, Wurzburg Loan 1, Dundee Medipark, DD2 1FD Dundee, United Kingdom. Electronic address: Fabiola.FG@gmail.com.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Fernandez-Gutiérrez
authors.affiliation: SINTEF Technology and Society, Department of Medical Technology, Olav Kyrres gate 9, MTFS, Trondheim, Norway. Electronic address: Thomas.Lango@sintef.no.
authors.forename: Thomas
authors.initials: T
authors.lastname: Langø
authors.affiliation: Fraunhofer MEVIS, Institute for Medical Image Computing, Universitätsallee 29, 28359 Bremen, Germany. Electronic address: Jan.Strehlow@mevis.fraunhofer.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Strehlow
authors.affiliation: Fraunhofer MEVIS, Institute for Medical Image Computing, Universitätsallee 29, 28359 Bremen, Germany. Electronic address: Sabrina.Haase@mevis.fraunhofer.de.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Haase
authors.affiliation: Amper Kliniken AG, Klinikum Dachau, Department of Clinical and Interventional Radiology, FUS-Center, Krankenhausstrasse 15, D-85221 Dachau, Germany. Electronic address: Matthias.Matzko@gmail.com.
authors.forename: Matthias
authors.initials: M
authors.lastname: Matzko
authors.affiliation: Sapienza University of Rome, Department of Radiological, Oncological and Pathological Sciences, V.le Regina Elena 324, 00180 Rome, Italy. Electronic address: Alessandro.Napoli@uniroma1.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Napoli
authors.affiliation: University of Dundee, College of Medicine, Institute for Medical Science and Technology, Division of Imaging and Technology, Wurzburg Loan 1, Dundee Medipark, DD2 1FD Dundee, United Kingdom. Electronic address: A.Melzer@dundee.ac.uk.
authors.forename: Andreas
authors.initials: A
authors.lastname: Melzer
authors.affiliation: Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Department of BioMechanical Engineering, TUD-3mE-BmechE, Mekelweg 2, 2628 CD Delft, The Netherlands. Electronic address: J.Dankelman@tudelft.nl.
authors.forename: Jenny
authors.initials: J
authors.lastname: Dankelman
mesh_terms: D000328:Adult; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D008962:Models, Theoretical; D009038:Motion; D013997:Time Factors; D059708:Ultrasonic Surgical Procedures / Q000379:methods*; D014599:Uterus / Q000000981:diagnostic imaging / Q000601:surgery; D057188:Workflow; D055815:Young Adult
keywords: Focused ultrasound surgery; High intensity focused ultrasound; MRgFUS; Workflow analysis; Workflow simulation