• RecurringMeetings
• 2016-01-26

Recurring Meeting of Cleveland Clinic Core Team

Date: January 26, 2016

Time: 2:00 PM EST

Means: In person meeting

Attendees:

1. Ahmet Erdemir
2. Tammy Owings
3. Benjamin Landis
4. Robb Colbrunn
5. Tara Bonner
6. Callan Gillespie

Agenda:

1. Discuss immediate action items from past meetings.

   • http://wiki.simtk.org/multis/RecurringMeetings/2016-01-19

2. Design of ultrasound probe / force transducer handle.
3. Decide immediate action items for next meeting.
4. Other.

Immediate Action Items:

• Ahmet
  • Continue working on the design of ultrasound probe - force transducer attachment.
  • Start designing a cable holder to accommodate cable weight on the handle.
• Tammy
  • Meet with physicians to shadow for training on musculoskeletal imaging using ultrasound.
• Ben
  • Try running the simplified indentation model under large displacements.
  • Try attaching a spring to stabilize the indenter in the simplified model to accommodate force control.
• Robb
  • Document surgical tools and their handling on the wiki with photos.
  • Complete wiring to synchronize ultrasound imaging and force measurements.
  • Explore installing a gyroscope on the force transducer for measurement of probe orientation.

Notes:

1. Discuss immediate action items from last meeting.
   • Ahmet showed a 3D printed part based on the scans of the 9L4 ultrasound probe. This step ensured that any printed parts will confirm to the probe and can be used effectively to clamp it. Robb raised the issue that the weight of the ultrasound probe cable may influence force measurements. He recommended holding the cable with the hand used for holding the outside casing or attaching the wire to the handle. Ahmet will look into this.
   • Tammy was out of office last week. She got in touch with physicians for learning more about musculoskeletal imaging using ultrasound.
   • Ben provided drawings of ultrasound probes to illustrate measurement sites for quality assurance of 3D scans. He provided the drawings in the in-house data management system along with 3D scans and within the spreadsheet on scan accuracy.
   • Ben has been running simulations in FEBio using the simplified indentation model.
     • He started utilizing more realistic dimensions for tissue radii. He implemented properties from Petre et al. (2013) for skin, fat, and muscle. He confirmed that the indenter was modeled as an elliptical surface with gross dimensions approximating ultrasound probe.
     • Ben had trouble getting the simplified indentation model model convergence under force control. Ahmet mentioned that rigid body degrees of freedom without stiffness definitions may cause this issue. He recommended Ben to attach a spring with low stiffness to stabilize the indenter.
     • Ben will explore convergence at larger indenter displacements. He raised concerns about contact, e.g. facet to facet contact based on penalty. Ahmet asked him to try contact formulation based on Lagrange multipliers as this will have the most stringent enforcement of contact constraints (no penetration). If convergence fails, he asked Ben to switch penalty formulation with increased penalty parameter (contact stiffness).
     • Ahmet mentioned that the actual workflow of modeling will start with stl surfaces that need to be meshed and imported into FEBio for finite element analysis. He recommended that Ben keeps this in mind.

   • In relation to documenting surgical tools with photos, Robb asked about creating thumbnails in the wiki. Ahmet recommended using the "ImageLink" command, where one can specify the size of the image. Robb will use this for attaching the photos and documenting handling of surgical tools.

   • Robb started working on cabling to synchronize ultrasound imaging and force measurements. The next step is to complete the wiring and send a sample signal to ultrasound.
   • Tara updated force collection interface to implement all anatomical locations for data collection. In a related discussion, the group discussed installing a gyroscope to record orientation of the ultrasound probe simultaneously with the force measurements. This will allow subtraction of probe weight from measurements to calculate actual indentation loads. After taring of the transducer, a calibration trial need to be performed to establish the relationship between orientation and forces/moments due to probe weight.
2. Design of ultrasound probe / force transducer handle.
   • See relevant discussions in the agenda item above.
3. Decide immediate action items for next meeting.
   • See Immediate Action Items above.
4. Other.
   • Ahmet mentioned that he asked BME administration to sent an offer to the candidate for the engineer position, who has visited the laboratory last week for an interview. He also reminded the team members that a candidate for the research associate position will arrive by the end of the week for an interview.