High-Resolution Episcopic Microscopy (HREM) / HREM vs Micro-CT
HREM vs Micro-CT for 3D Morphology
Comparing imaging approaches for detailed analysis of embryos, organs, and complex tissue structures.
Quick Comparison of HREM vs Micro-CT
HREM | Micro-CT | |
|---|---|---|
Principle | Serial block-face optical imaging during sectioning, meaning destructive though sample slices recoverable | X-ray attenuation imaging with computational reconstruction, meaning non-destructive |
Contrast mechanism | Sample preparation enhances block fluorescence through negative contrast | Density differences, soft tissue often requires contrast agents |
Typical resolution | 1-5 microns, with greater XY achievable below 1 micron | 5-50 micron typical, with the possibility to decrease to below 5 |
Soft tissue detail | Excellent | Limited without staining |
Mineralised tissue | Limited contrast for mineralised structures | Excellent |
Sample sizes | Small to medium (e.g embryos, organs, plant structures) | Small to large specimens |
Sample preparation | Fixation, dehydration, embedding & staining. Moderately time consuming. | Fixation, optional contrast agents. Relatively time efficient if no staining. |
How HREM and Micro-CT Work
How HREM works?
HREM is a serial block-face imaging technique, which means imaging the sample section by section. This allows for dense structures to be visualised easily with histology-like contrast.
How Micro-CT works?
Micro-CT is in its simplistic form a resultant reconstruction from projections of X-Ray penetration. Which often requires staining for soft tissue but incredible clarity on denser bone structure.
Soft Tissue Imaging with HREM
One of High Resolution Episcopic Microscopy (HREM)s biggest benefits is its ability to image soft tissue, with internal structures delivering high contrast. This allows for incredibly fine changes to be visualised and quantified with cellular level detail possible. Micro-CT is often limited without extra staining and even then may struggle to achieve the contrast that HREM can on the smaller internal structures.
Typical Applications
When Researchers Choose HREM
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Mouse embryos
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Congenital heart defects (CHD)
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Organ morphology
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Developmental biology
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Phenotyping studies
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Detail tissue architecture
When Researchers Choose Micro-CT
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Bone imaging
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Skeletal development
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Large specimens > 20mm
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Mineralised structures
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Gross anatomy
Advantages and limitations
HREM and Micro-CT have fantastic results, depending on the size and expected intent for the images. HREM offers high-resolution, excellent soft tissue clarity and minimal reconstruction artefacts. However, is a destructive technique that has a reduction in contrast in larger or mineralised samples without extra preparation.
It is important to also mention on scanning setups HREM resolution is not limited to the size of the sample but the resolution required, with newer preparation and optical setups allowing for staining of structures, while traditionally being used for simple morphology the technique now branches into newer possibilities.
Micro-CT on the other hand is excellent at imaging mineralised components, offers fast scanning as well as use with larger samples. However, lacks the fine soft tissue detail that you will see in HREM for smaller samples.
Choosing the right method
HREM and Micro-CT often work well together allowing for structural analysis as well as fine detail analysis. Being similar in resolution often lends itself to the comparison between the two but both offer very different strengths. HREM is often a preferred choice for smaller structures to help visualise very small changes, this includes the heart. This being said it does lack the ability to image mineralised structures, increased sample preparation and destructive to the sample. Micro-CT lends itself to larger structures, with skeletal structures being easily quantifiable this comes at a trade off of soft tissue clarity.
Ultimately the choice lies in the sample type, analysis type, cost and performance characteristics you require most.
Contact our team
Contact our team to for a quote or more information on Optical HREM products.
Phone:
+44(0) 1462633500
Email:
hello@indigo-scientific.co.uk