Weekly Update in lieu of Recurring Meeting of Cleveland Clinic Core Team
Date: June 20, 2017
Provided by: Snehal Chokhandre
Ongoing Action Items:
- Review drafts of data manuscripts for submission.
- Complete studies for tissue testing reproducibility.
- Continue tissue testing of Open Knee(s) specimens.
- Continue segmentation of Open Knee(s) specimens.
- Tissue testing.
- Snehal completed a week long repeatability set for cartilage tension (48 yr old specimen). Snehal did not accommodate the 300 micron offset in the values for preconditioning for the first test.This test was hence discarded. For the following tests Snehal made sure all the procedure / protocols were closely followed and checked. For the last test, Mach-1 motion software froze and that test also had to be discarded.
- The repeatability from the three tests has high variability. Previous cartilage tensile repeatability test set showed a very good repeatability. That set however did not have the ramp load-unload steps before and after preconditioning. Also, the length values for this set appear to always be lower after preconditioning than before. This is not typical. Snehal is repeating this set for another sample from a neighboring location. Snehal also thinks the large variability may be due to the sample being thicker (~0.7 mm).
- The sample Snehal is working on this week is ~5mm thick. The first two tests for this set show a good repeatability and is encouraging. It appears that the sample thickness (and hence clamping) is more of a factor than the ramp load-unload in the preconditioning sequence.
- The current sample is taken from the deeper layer as the sample from the superficial layer was damaged.
- Snehal contacted Biomomentum, Inc. to request resolution for the Mach-1 motion software error. The error seem to be due to the fact that camera outputs are saved one at a time and not in a batch. Martin is working on finding a way to circumvent that but for now he suggested using a lower sampling rate for the camera. However, Snehal is already using 1 Hz for preconditioning but needs maximum images from the stress relaxation ramps where the error occurred (3 /4 images as of now with 10 Hz) and reducing the sampling rate would lead to no usable image data for ramp loading.
- Snehal updated the cartilage testing specifications on the wiki page.
- Snehal received the thicker stainless steel filter for confined compression and will get that cut to size by the prototype lab. She will resume confined compression test set after finishing the tensile sets for both the 78 yr old and 48 yr old specimens.
- Data manuscripts.
- No progress.
- No progress.
- Snehal compared the segmentation she performed for oks001 patella cartilage to that done by Craig to assess the regions of maximum variability after calculating the Hausdorff distances. She also compared them both to the image set to gage where the over/underestimation is occurring. She seems to have overestimated certain areas that were not very clearly visible or missing.
- After correcting the segmentation and regenerating the geometry using geometry generation specifications, she compared the geometry to that created by Craig. The updated segmentation/geometry appears to be much closer to Craig's attempt. (see updates on Cases/ImageSegmentationVariability).
- Snehal is now working on indentation simulation for the two geometries (updated geometry by Snehal and Craig's geometry).