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NCI CCR Comparative Molecular Pathology Unit Guide to Imaging Modality Selection for Small Research Animal Models of Human Disease



Some Considerations for Selecting Among Imaging Modalities Currently in NIH Mouse Imaging Facility

Imaging Modality Acquisition Speed Strengths Weaknesses Spatial Resolution Tissue Contrast
Computed Tomography (CT) Moderately fast (seconds to many minutes) High-detail cross-sectional anatomy. Better soft tissue discrimination than conventional radiographs. Relatively inexpensive. Soft tissue contrast is only moderate. Spatial resolution and image clarity is determined by acquisition time. Depends on scanner.
Clinical scanner (0.2 – 0.3 mm)
High-resolution research scanner (10s of microns)
Excellent bone contrast. Moderate soft tissue contrast.
Magnetic Resonance Imaging (MRI) Slow (minutes to hours) High-detail cross-sectional anatomy with excellent soft tissue contrast. Imaging parameters can be tailored to optimize imaging of a particular organ or lesion. Long image acquisition times. Cannot be used to image bone or aerated organs such as the lung. Interventions and monitoring are limited due to the magnetic environment. Spatial resolution and image clarity is determined by acquisition time. Expensive Depends on scanner
Clinical scanner (0.2 – 0.3 mm)
High resolution research scanner (10s of microns)
Excellent soft tissue contrast.
Poor contrast for dense bone
Ultrasound (US) Fast (seconds to minutes) High-resolution cross-sectional images with good soft tissue contrast. Best used for imaging solid or fluid filled viscera. Relatively inexpensive. Image quality is more operator dependent that for other modalities. Output is therefore more variable. Limited utility for imaging dense cortical bone or aerated organs such as lung. Moderate spatial resolution (0.2 mm) for clinical scanners. Some high frequency transducers may provide higher resolution. Good soft tissue contrast but less than MR.
Optical Imaging (OI) Fast (millseconds – seconds) Planar images with extremely high detector sensitivity for tracer detection. Currently requires cell labeling. Planar images of relatively low spatial resolution. Depth of detection in tissue is limited. Expensive poor Very high contrast between labeled and unlabeled tissues

The spatial resolution numbers included in this table are approximate and may vary significantly depending on the specific imaging equipment used. Strengths and weaknesses are generalizations relating to typical clinical applications and may not apply for certain research uses.

Features of Imaging Modalities Projected for Future Use

Imaging Modality Acquisition Speed Strengths Weaknesses Spatial Resolution Tissue Contrast
Radiography Fast (milliseconds) High throughput. High spatial resolution. Inexpensive. Anatomical structures are superimposed making interpretation more difficult. High resolution (50-100 microns) Excellent bone contrast. Poor soft tissue contrast
Scintigraphy Fast (seconds to minutes) Planar images with extremely high detector sensitivity for tracer detection. Planar images of relatively low spatial resolution. Poor spatial resolution. (0.5 mm or more) Very high contrast between labeled and unlabeled tissues
Photon Emission Tomography (PET) Moderately fast (minutes) Tomographic images with extremely high detector sensitivity for tracer detection. Image resolution is less than some other imaging modalities. Requires cyclotron. Expensive Depends on Scanner.
Clinical Scanner (mm)
MicroPET (6 microliter volume resolution)
Very high contrast between labeled and unlabeled tissues

The spatial resolution numbers included in this table are approximate and may vary significantly depending on the specific imaging equipment used. Strengths and weaknesses are generalizations relating to typical clinical applications and may not apply for certain research uses.

Tables adapted and used with permission from Erik Wisner, D.V.M., Diplomate, and Past President of The American College of Veterinary Radiology. Published in Conference Proceedings, 52nd Annual Meeting of The American College of Veterinary Pathologists, Salt Lake City, UT, 2001, pp. 186-191, by The American College of Veterinary Pathologists, 7600 Terrace Ave., Suite 203, Middleton, WI 53562. http://www.acvp.org