Capillary Density¶
You can use the HVCS CapiScope either handheld in contact, or in the stand non-contact. Below is a suggested protocol for measuring capillary density.
Handheld¶
Capturing Video¶
Fit a new Probe Cover.
Hold the probe gently against the skin and adjust the focus using the focus ring.
Remove probe and apply a drop of oil to the skin. (Any clear oil will do such as parafin oil/baby oil, olive oil, massage oil, etc. This will give good optical matching between the probe and the tissue reducing surface reflection allowing to see beneath the surface.
Replace probe and adjust focus.
Hold the probe gently against the skin. At zero pressure when the probe tip moves off the tissue you will see the oil separate from the probe like a big bubble. You’ll only need just a bit more pressure than this to make contact.
You may need to increase brightness using the slider in the “video” control in the software. Once you’ve clicked on the slider you can use the up and down arrow keys for finer control. If too much pressure is applied, then blood will be occluded and the tissue will become whiter and the image brighter or saturated.
You will need to adjust the focus slightly. One turn of the focus ring = 1 mm so you shouldn’t need more than 1/2 turn.
Its easiest if you hold the device in the right hand with the focus ring between thumb and finger. In this way, up, down etc corresponds with the image on screen.
Press the red “record” button. Slowly move the probe over the area to be measured, adjusting focus if necessary. Press the “record” button again to stop recording. Press the “Save” button and save the recording.
The length of the recording can be set in the menu “settings”, “image sequence”. A typical value might be 10 - 30 seconds. Video is uncompressed, so produces large files. One second is about 10Mbytes. 30 seconds will produce a file of about 300Mbytes. A 4.7Gbyte DVD will hold about 15 x 30 second clips.
When saving clips, the windows filesystem is used, so files can be organised into folders and descriptive filenames. Alternatively, CapiScope can be set to save video clips automatically everytime the recording is stopped. This is set in the “settings”, “video sequence” dialog box. You can also set a basename for the files, and specify the folder to save in. Files will be saved with basename plus a number unique to the time saved.
Analysing Video¶
Open the video file.
Press the lower “play” button, or drag the horizontal scrollbar to the first good image in focus.
Select menu “edit”, “duplicate image in new window”.
Press toolbar button “find capillaries”.
Check the resultant located capillaries and delete any false positives. Use the toolbar button “counting” and click on any missed capillaries. Press “=” key or the “=” toolbar button to get the “Dim count density”.
Use the “play” or scrollbar to find the next area and good focus. Repeat steps 2 – 5 for the rest of the recorded clip.
Save the image results window, or select, copy and paste the dimension count density results into Excel or other spreadsheet.
Save the individual measurement images if required.
Individual images have a filesize of only 354kbyte. A 4.7 Gbyte DVD would hold over 1000 images.
Note that both video and images are saved as two files each: a small header file and then the image/video file. The header file contains the magnification, the dimensions data, capture time, etc. Images are saved as windows BMP bitmap format. Video is saved in a KK Technology raw format.
