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KASM Newsletter May 2015
How to efficiently extract meaningful
information from histological slides?
Michael Chou and Aruna Somasiri
To extract meaningful information out of histological slides, most researchers
capture region of interests using digital cameras mounted on their light
microscopes. Images are taken and saved in .tiff or .jpeg formats for a number of
quantitative measurements, such as lengths and area. Researchers have become
comfortable using ImageJ, a free and highly customizable image processing
program
from
National
Institute
of
Health
and
is
available
at
http://imagej.nih.gov/ij/, to quantify captured images from their histologically
stained samples. To do so properly, one has to determine and calibrate the scale
for each image file taken at specific magnification. One has to search through
slide boxes for the desired samples for recapturing if the images are not finely
focused or if higher magnification is required for publication. It is not uncommon
to observe faded stains after a period of time. Whole Slide Images (WSIs) not
only save time and the troubles mentioned above, but also minimize potential
human errors from setting scales. One could efficiently quantify tissues on a
computer monitor without scale calibration, as actual scales of samples are
embedded within WSIs (Figure 1).
Figure 1. Actual scale
of a hematoxylin and
eosin (H&E) stained
adipose tissue section
is embedded in a WSI.
Scale is automatically
adjusted when one
observe the sample in
different
magnification. (B to D)
Higher magnifications
of the green dotted
square in A.
Magnifications (A to
D): 1X, 5X, 10X and
20X. Scale bars (A to
D): 2mm, 400um,
200um and 100um.
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KASM Newsletter May 2015
WSIs digitally preserve the stains and make ease of future reassessment.
Efficiency and accuracy are equally important for analyzing large-scale animal
experiments. For example, quantifying 3100 villi and crypts with a bright-field
microscope would be inefficient. With WSIs, one simply opens a colon WSI file,
measures villus heights and crypt depths and exports the quantification in Excel
files for further statistical analyses (Figure 2).
Figure 2. WSI ease mass
quantification of drug efficacy
using H&E stained proximal
jejunum section of a mouse. (B)
Villus height, in green, and crypt
depth, in yellow, could be
accurately measured without
scale calibration by zooming into
green dotted area in A. Scale
bars in A and B: 400um, 200um.
Figure 3. WSI enables
researchers to effectively
study hypertrophic scar
model using H&E stained
rabbit ears. (B) Areas of
newly formed hypertrophied
(Region 2) and underlying
(Region 1) dermis could be
determined accurately for
calculating scar elevation
index. Scale bars in A and B:
2mm, 700um.
WSIs ease quantification and analysis for studying wound healing using rabbit
ears (Kloeters et al., 2007). In this case, areas of different dermal regions could
be easily measured on a computer monitor (Figure 3). Our customized WSI
and image analysis services have helped our clients to effectively
manage their studies in reaching significant milestones. How could
we help to translate your pixels into success-leading decisions?
Reference
Kloeters, O., Tandara, A. & Mustoe, T. (2007). Hypertrophic scar model in the rabbit ear: a
reproducible model for studying scar tissue behavior with new observations on silicone gel
sheeting for scar reduction. Wound Rep Reg, 15, S40-5.
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