B-K Medical Pro Focus 2202, User Manual

Page: 233 / 356

Urology Pro Package 233
HWL
HWL is a method of calculating a volume using height, width and length
measurements. To use this method to calculate the volume of a particular organ, use
the Height, Width and Length measurements in the submenu for that organ volume.
To calculate an HWL volume:
1
Click Height and measure the height.
The height appears under Measurements to the left of the image.
2 Click Width and measure the width.
The width appears under Measurements to the left of the image.
3
Click Length and measure the length.
The length appears under Measurements to the left of the image.
The calculated volume appears under Measurements to the left of the image.
The height, width and length measurements must be made at right angles to each
other. Therefore, you must use 2 scanned images for HWL calculations.
To make a measurement in the other part of a split screen:
•
Press
[
C
]
.
or
• Move the cursor to the other screen and click.
Planimetry
For this method, you record a number of parallel B-mode images that cover the organ
to be measured. On each image, you draw a curve that traces the outline of the
structure. Thus you create a set of parallel section measurements of the structure.
These parallel sections (the outline measurements) are used to estimate the volume
of the structure based on a number of equally spaced slices.
The accuracy of this method depends on starting the measurements in the correct
place. Start at one end of the organ, where the scanned image shows an area of as
close to 0 as possible. After each step, trace the outline of the structure on the scanned
image. The system calculates the volume of the structure between the starting point
and each new scan (see Fig 16-1). This is continued until the whole organ has been
covered and a total volume obtained.