Dynamic Circle Cursor for Paintbrush\Erase: completely re-engineered
a) Cursor generated on-the-fly, avoiding start-up delay and excessive memory allocation
b) No limit for the cursor size - "Halo" defect is supposed to disappear.
Search This Blog
Monday, November 20, 2017
Tuesday, November 14, 2017
Monday, November 13, 2017
Sunday, November 12, 2017
2CXM model: two variants were implemented - NLLS and LLS
With LLS variant a double integration is performed and the corresponding 4x4 linear system is solved using SVD. Resulting solution is converted to physiological parameters {vp,ve,PS,Fp} and substituted to an analytical solution containing a convolution of two different exponents with the AIF.
Tests were performed on the GRASP-4D with 76 timepoints [0,411] sec.
Small ROI (yellow was chosen)
First we performed the fitting with "ROI as a single TAC".


A good fit was observed RMSE=25. But corresponding parameters contain the negative value, which is not physiological.
Next we performed voxel-by-voxel fitting. This model #45 2CXM-LLS has a single hyperparameter "Exclude invalid", which optionally excludes the unphysiological voxels from the map (defaullt=0 - Include all).
If we turn "Exclude Invalid =1", this would exclude the voxels from the result where one of the key fittted parameters are negarive: this includes transit times {T,Te,Tp} and {vp,ve,PS}
When such invalid voxels are removed, we can see that a minor portion of the ROI resulted in non-negative parameter values.
NLLS variant: gridded Simplex algorithm was used.

Below is the fitting residual comparison for LLS and NLLS.
With LLS variant a double integration is performed and the corresponding 4x4 linear system is solved using SVD. Resulting solution is converted to physiological parameters {vp,ve,PS,Fp} and substituted to an analytical solution containing a convolution of two different exponents with the AIF.
![]() |
| Sample ROI for the test |
Small ROI (yellow was chosen)
First we performed the fitting with "ROI as a single TAC".


A good fit was observed RMSE=25. But corresponding parameters contain the negative value, which is not physiological.
Next we performed voxel-by-voxel fitting. This model #45 2CXM-LLS has a single hyperparameter "Exclude invalid", which optionally excludes the unphysiological voxels from the map (defaullt=0 - Include all).
![]() |
| LLS: Residual distribution [0,100] (include all mode) |
![]() |
| Fitting with unphysiological (invalid) voxels removed. |
When such invalid voxels are removed, we can see that a minor portion of the ROI resulted in non-negative parameter values.
NLLS variant: gridded Simplex algorithm was used.

Below is the fitting residual comparison for LLS and NLLS.
![]() |
| LLS: fit residual distribution [0,100] |
Saturday, November 4, 2017
Friday, November 3, 2017
Monday, October 30, 2017
Saturday, October 28, 2017
Thursday, October 26, 2017
Wednesday, October 25, 2017
Sunday, October 15, 2017
Friday, October 6, 2017
Thursday, October 5, 2017
Tuesday, October 3, 2017
Thursday, September 28, 2017
Tuesday, September 26, 2017
Friday, September 15, 2017
Thursday, September 14, 2017
Tuesday, September 12, 2017
Wednesday, September 6, 2017
Monday, September 4, 2017
Friday, September 1, 2017
Thursday, August 31, 2017
Wednesday, August 30, 2017
Tuesday, August 29, 2017
Monday, August 28, 2017
Sunday, August 27, 2017
Polyline segment measurement functionality:
Implemented a function so that the length of the Polyline segments is displayed in real time
while the user is dragging the polyline. This only works in Orthogonal projections for now.
The corresponding flag is under MainMenu>Measurement>Display Curve Length
Implemented a function so that the length of the Polyline segments is displayed in real time
while the user is dragging the polyline. This only works in Orthogonal projections for now.
The corresponding flag is under MainMenu>Measurement>Display Curve Length
Saturday, August 26, 2017
Wednesday, August 9, 2017
Tuesday, August 8, 2017
Monday, August 7, 2017
Tuesday, August 1, 2017
Monday, July 31, 2017
Monday, July 24, 2017
Thursday, July 13, 2017
Monday, July 10, 2017
Monday, July 3, 2017
1. Extended FireVoxel valid dates.
2. Updated the "Applications>Breast FGT>Sagittal..." menus
3. Fixed the problem with loading the ".mgz" files.
4. Fixed the "jumping cursor" issue inside the Layer Control Dialog
5. Fixed the "Window Center\Level" problem indicated on the Brain image showing too dark
6. Fixed the "Infinite loop" problem, when the VROI tool was activated over the empty area
of the document not containing the volume (FilmView)
7. Removed 2 "Rasterize" items from the MainMenu>Trace. User instead should use the Rasterize
item of the Main toolbar.
2. Updated the "Applications>Breast FGT>Sagittal..." menus
3. Fixed the problem with loading the ".mgz" files.
4. Fixed the "jumping cursor" issue inside the Layer Control Dialog
5. Fixed the "Window Center\Level" problem indicated on the Brain image showing too dark
6. Fixed the "Infinite loop" problem, when the VROI tool was activated over the empty area
of the document not containing the volume (FilmView)
7. Removed 2 "Rasterize" items from the MainMenu>Trace. User instead should use the Rasterize
item of the Main toolbar.
Tuesday, June 27, 2017
Thursday, June 22, 2017
Friday, June 9, 2017
Thursday, June 8, 2017
New Dynamic model was implemented:
"Variable Flip Angle T1 recovery S = M0*(1-exp(-TR/T1))*sina(A)/(1-exp(-TR/T1)/cos(A)) "
It appears as the model #24 on the FireVoxel Dynamic Experiment Framework
Model has 2 hyperparameters defining the Local optimization as in Deoni2003 and FireVoxel global optimization. In case of the Global optimization we also can set the # of iterations, but it can be kept default.
There are 3 output parameters: T1 (ms), M0 and fitting residual.
To test the model a Brain ROI (mask) was detected on the max signal timepoint using the standard EdgeWave algorithm and parameters.
We ran algorithm with both linear and global optimization and found out that global optimization finds a 20% smaller residual on average, while reducing the Max residual by x2.5 times.
The following T1 map was obtained:
... with the corresponding Fitting Residual map
Typical fitting for a single voxel looks like this:
For this particular fitting:
Linear Optimization: T1 = 1238 ms
Global Optimization: T1 = 12.64 ms
i.e. about ~3% difference
"Variable Flip Angle T1 recovery S = M0*(1-exp(-TR/T1))*sina(A)/(1-exp(-TR/T1)/cos(A)) "
It appears as the model #24 on the FireVoxel Dynamic Experiment Framework
Model has 2 hyperparameters defining the Local optimization as in Deoni2003 and FireVoxel global optimization. In case of the Global optimization we also can set the # of iterations, but it can be kept default.
There are 3 output parameters: T1 (ms), M0 and fitting residual.
To test the model a Brain ROI (mask) was detected on the max signal timepoint using the standard EdgeWave algorithm and parameters.
We ran algorithm with both linear and global optimization and found out that global optimization finds a 20% smaller residual on average, while reducing the Max residual by x2.5 times.
![]() |
| Residual statistics for Linear optimization: Mean=12.1, Max=215.8 |
![]() |
| Residual statistics for the Global Optimazation: Mean=10.4 Max=97.5 |
The following T1 map was obtained:
... with the corresponding Fitting Residual map
Typical fitting for a single voxel looks like this:
For this particular fitting:
Linear Optimization: T1 = 1238 ms
Global Optimization: T1 = 12.64 ms
i.e. about ~3% difference
Wednesday, June 7, 2017
Thursday, June 1, 2017
1. Integrated Variable Flip Angle as the new dynamic dimension. This would allow corresponding VFA volumes to be processed inside the parametric modelling framework.
2. Provided backward compatibility for all existing FVX document files (v1-v5) and v6 format was introduced.
3. Ensured the ABT test is completing correctly since it is using old file formats.
2. Provided backward compatibility for all existing FVX document files (v1-v5) and v6 format was introduced.
3. Ensured the ABT test is completing correctly since it is using old file formats.
Tuesday, May 23, 2017
Subscribe to:
Posts (Atom)





































