This free webinar hosted by Scintica Instrumentation reviewed the fundamentals of Magnetic Resonance Histology (MRH) and provided a number of relevant examples. Magnetic Resonance Imaging (MRI) has been used for years in preclinical research to perform in vivo studies allowing for the sensitive detection of pathological changes in soft tissue and to provide quantitative three-dimensional data.It has been used in longitudinal studies to noninvasively monitor the genesis, progression and regression of a wide variety of diseases, reducing the need for interim sacrifice of animals at specified time points, thus allowing the same animal to be used as its own control within a given study. MRH is the use of MR imaging on formalin-fixed tissues for high resolution characterization of tissue structure. It is a highly valuable complimentary adjunct to conventional histopathology, as it permits a thorough examination to be performed through multiple digital slices of an entire organ, while leaving the formalin-fixed specimen intact for subsequent definitive conventional diagnostic histopathology.

1. Dr. Abraham Nyska;
DVM, Dipl. ECVP, Fellow IATP
Please contact Scintica Instrumentation for
additional information:
Phone: +1 (519) 914 5495
info@scinticainstrumentation.com
Expanding preclinical and
histopathology
capabilities with MRI
technology: a useful tool
for preclinical safety and
efficacy evaluation
cortex X 200
medulla X 200
Ex-vivo - MRH
Control Kidney
cortex X 200
medulla X 200
Acute Kidney Injury
Ex-vivo - MRH

2. • This presentation addresses the practical applications of
compact MRI, and will demonstrate practical concept examples
in the fields of “smart toxicology” and “smart histology” .
• The presentation will demonstrate how compact MRI
technology can serve as an important adjunct to toxicology and
toxicologic pathology by nondestructively providing 3-
dimensional (3-D) digital data sets, detailed morphological
insights, and quantitative information.
Webinar Objective

3. • Brief introduction to MRI Technology and Terminology
• Concept of MRI-based Histology
• Presentation of Various Preclinical Models
• Conclusion and Live Q&A Session
Presentation Overview

4. MRI Technology and Terminology

5. Magnetic Resonance Imaging Technology
• MRI has come a long way
• Smaller
• Less expensive
• Easier to use
• Non-clinical applications
• Quantify tissue alterations
• Monitor disease progression
• Assess efficacy and response

6. In Vivo Imaging – The Future is Now!

7. In Vivo Imaging – Don’t Choose, Fuse!

8. Advantages of MRI in Toxicology
• Non invasive - Permits longitudinal in vivo imaging to follow disease in the same animal (better statistics, less
animals required)
• Can acquire numerous digital slices from whole fixed organs in any plane without destroying the specimen
• High soft tissue contrast as well as good bone visualization
• Provides a means to obtain quantitative data
Provides complimentary information to conventional pathology - Better practice, safer
drugs/products

9. MRI – A Psychological Barrier
• Expensive equipment
• Expensive maintenance
• Special facility required (shielded room)
• Safety issues (no metals around)
• Hard to operate
• For “MR gurus” only - High level of expertise required

10. Shift Happens – Compact MRI for Everyone
• Compact
• Quiet
• Affordable
• Easy to use
• Safe
• No special facility
• Maintenance-free

11. MRI Made Easier
• Complicated Software… No more
• Tons of Parameters to Optimize…
No more
• One Touch MRI - Ask. Touch.
Answer

12. MRI Terminology
• By changing the frequency, duration and timing of applied magnetic fields and radio frequency (rf) pulses,
MRI can provide what are basically “MRI stains”
• Most common “MRI stains” (Types of contrast) - T1 and T2

13. MRI Terminology
T2T1

14. Any Plane Can Be Imaged
axialsagittal coronal

15. MRI Data Presentation – Individual Slices

16. MRI Data Presentation – Slice Through Animation

17. MRI Data Presentation – See Through 3D Rendering (MIP)

18. Segmentation – Volume Calculation

19. MRI-based histology – “Smart sections”
Or
“Smart histology”

20. MRI-based Histology - Smart Sections Added Value for
Lesion Evaluation
• Localize the lesions
• Count the lesions
• Measure lesions volume
• Longitudinal in vivo follow-up in the same animal
• Information about homogeneity of the lesions

21. Methods
• All scans performed on a M-series compact MRI by Aspect
Imaging
• Animals
• Anesthetized with isoflurane
• Heated
• Physiological monitoring
• Fixed samples
• In any fixative solution
• Fluorinert

22. Preclinical Models to be Presented

23. Models That Will Be Presented
• Detection of preneoplastic lesions in the liver
• Toxicity follow-up in the kidney
• Assessment of subcutaneous local tolerability
• Testing the efficacy of anti-cancer drug in brain tumor model
• Evaluating the efficacy of lung antifibrotic potential of a drug;
• Combining the Compact MR capacity in the assessment of cancerous potential of novel therapeutic stem cells

24. Focal Hepatic Lesions
• Model: Mdr-/- mouse develops multiple focal hepatic lesions
• Objective: Detect and measure volume of multiple focal lesions

25. Detection of Multiple Focal Lesions in Mouse Liver
In vivo MRI
hepatic
lesions
liver
kidney
ip. fat
sc. fat
hepatic
lesion
resolution 270 mm; slice thickness 1mm; acquisition time 3.5 min

26. Multiple Focal Lesions in Mouse Liver ex vivo MRI
resolution 156 mm; slice thickness 0.7 mm; acquisition time 35 min

27. Segmentation of Lesions Based on ex vivo MRI

28. Quantification of Lesions Based on ex vivo MRI
• 15 distinctive lesions were detected
• The smallest lesion detected had a diameter of 0.6 mm
• The largest lesion had a diameter of 4.8 mm
• Total liver mass 2593 mm3
• Total lesion mass 60.3 mm3 (2.3%)

29. Segmentation of Lesions Based on ex vivo MRI

30. Classification of Liver Lesions as Focal Fatty Changes by
Histopathology

31. Summary and Comment
• In vivo and ex vivo MRI evaluation were effective in identifying the location and measuring the volume of focal
changes in the liver
• This approach using in vivo MRI would allow for following lesion development over time
• In this study the MRI was done after lesions were fully developed, however, longitudinal studies using in vivo
MRI would easily be feasible in this model

32. Rhabdomyolysis -Induced Acute Kidney Injury (AKI) in
Mouse
Mice Model of Glycerol-Induced AKI
IM 50% Glycerol
CB6F1 Mice
0 3 8 15
MRI + Blood
samples
Days
Mice Model of Glycerol-Induced AKI
IM 50% Glycerol
CB6F1 Mice
0 3 8 15
MRI + Blood
samples
Days

33. Control vs. Affected Kidney in vivo MRI
Control Affected
cortex
medulla
Day 3
• Loss of contrast
• Enlarged kidneys
resolution 234 mm; slice thickness 1mm; acquisition time 10 min

34. Following Disease Progression in vivo MRI
Day 0 Day 3 Day 8 Day 15
Contrast and size recoveredContrast lost and kidney enlargement

35. Control vs. Affected Kidney ex vivo MRI
Control Affected
cortex
medulla
papila
Loss of contrast
resolution 117 mm; slice thickness 0.5 mm; acquisition time 56 min

36. MRI and Histology – Control Kidney
cortex X 200
medulla X 200
Ex-vivo

37. MRI and Histology – Affected Kidney
cortex X 200
medulla X 200
Ex-vivo

38. Summary of Findings and Comment
• In vivo and ex vivo MRI were effective in identifying alterations in the cortex and medulla Histopathology:
Maximal extent of cortical necrosis and medullary hyaline cast formation
• In vivo and ex vivo MRI confirmed organ recovery. Histopathology: The previously necrotic tubules were
replaced by regeneration

39. Local Safety of Subcutaneous Formulations
• Model: In this study, subcutaneous lesions were analyzed by MRI 2 weeks after a 24-hour continuous infusion
of different formulations
• Objective of the experiment: This was a feasibility study for application of the ex vivo MRI in order to evaluate
the subcutaneous toxic effects induced at the injection site of test compounds

40. Subcutaneous Drug Injection Into Pig Skin MRI vs.
Histology
MRI (T1) Histology

41. H&E Histopathology
Blue = Multifocal areas of fat necrosis & associated inflammation
Red = Normal adipose tissue

42. Segmentation and Quantification of Affected Volume
Ex vivo MRI
Affected Volume 2200 mm3

43. Summary and Comment
• Ex vivo MRI was effective in identifying the location and quantifying the extent of subcutaneous necrosis and
inflammation caused by different formulations
• Applying this method on fixed tissues samples derived from different dose formulations provides a
quantitative determination of relative irritancy of different injected formulations

44. Longitudinal Growth of a Brain Tumor
• Model: Gl-261 glioma cells stereotactically injected into the right brain hemisphere of CB6F1 mice
• Objective: Longitudinal evaluation of tumor growth

45. Longitudinal Evaluation of Tumor Growth in vivo MRI
Day 15 Day 17 Day 20
axial
coronal
resolution 156 mm; slice
thickness 1 mm; acquisition
time 13 min

46. Ex Vivo MRI vs Histology
Day 15
Day 20

47. Summary and Comment
• In vivo and ex vivo MRI evaluation provided a way to follow the time-related growth of an induced tumor in the
brain and to determine the volume of the tumor
• This model demonstrates the utility of using MRI for longitudinal studies and would be useful for testing the
efficacy of anti-cancer drugs

48. Rat Lung Fibrosis
• Model: Single intratracheal instillation of bleomycin into 6 week-old Sprague Dawley rats
• Objective: Monitor lung fibrosis in rats using in vivo and ex vivo MRI as a tool for following temporal progression
of the pathological process

49. Rat Lung Control vs. Fibrosis in vivo MRI
control
fibrotic
Day 11 Post Instillation
resolution 274 mm; slice thickness 1.2 mm; acquisition time 4.5 min

50. Control vs. Fibrosis – Ex vivo MRI
Control Fibrosis
Day 11 Post Instillation

51. Fibrotic Rat Lung – Volume Quantification Based on
ex vivo MRI
Connective Tissue: 1267 mm3
Normal Tissue: 1396 mm3
Day 11 Post Instillation
3D rendering 3D rendering + segmentation

52. Histology – Masson’s Trichrome
controlfibrosis
High magnificationLow magnification

53. Summary and Comment
• In vivo MRI provides a longitudinal evaluation of pulmonary disease progression and regression
• Ex vivo MRI in combination with histology provides a quantitative assessment of the components of the
interstitial thickening
• Based on the ability to quantify the extent of disease, different therapeutic modalities can be compared for
their effectiveness

54. Compact MRI for the Assessment of Tumorigenicity
Following Intrathecal Transplantation of Human
Embryonic Stem Cells (hESC) in Mice

55. Materials and Methods
• Two mice injected with the vehicle control and 3 injected with hESC
• Injection within the inter-vertebral (L5 to L6) grove.
• Daily clinical evaluation
• In vivo MRI at 2 occasions (days 25 & 48)
• Sacrifice on day 55, followed by formalin fixation, ex vivo MRI, and histopathology

56. Spinal Teratoma - Segmented
ROI Color Voxels Volume mm³
teratoma red 1927 82.6201
In vivo Ex vivo

57. Spinal Rendering and Segmentation of the Spinal Cord

58. Brain Teratoma – in vivo & ex vivo MRI Segmentation vs.
Histology
In vivo Ex vivo Histology
ROI Color Voxels Volume mm³
tumor magenta 20539 9.79376

59. 3D Rendering of the Brain – Pink Areas are the Teratoma

60. Malignant Teratoma in the Spinal Cord

61. Results and Conclusions
• Paresis developed in mice injected with the hESC
• In vivo MRI located abnormal areas in the spinal column and brain
• Histopathology confirmed Malignant Teratoma
• In Conclusion: The MRI technique can be used for time course observations for testing the carcinogenic
potential of novel stem cells intended for clinical use.

62. MRI-based Histology – Smart Sections Added Value for
Lesion Evaluation
• Localize the lesions
• Count the lesions
• Measure lesions volume
• Longitudinal in vivo follow-up in the same animal
• Information about homogeneity of the lesions

63. Regulatory Perspectives…
• Citing from Dr. Bob Maronpot’s view concerning the future use of imaging data in conventional pre-clinical
studies submission to the FDA (i.e., this view was stated in Regulatory Forum Opinion Piece: Imaging
Applications in Toxicologic Pathology – Recommendations for Use in Regulated Nonclinical Toxicity Studies.
• “…We just have to take the stance that imaging as an adjunct to conventional histopathology makes the
histopathology that much better and allows for better sampling. The imaging also provided three-dimensional
quantitative data. I suspect providing imaging along with conventional histopathology could have positive
regulatory consequences ... Once FDA starts getting that sort of information, it may evolve to become a
desirable component of a submission. “

64. • Brief introduction to MRI Technology and Terminology
• Concept of MRI-based Histology
• Presentation of Various Preclinical Models
• Conclusion
Presentation Summary

65. Dr. Abraham Nyska
DVM, Dipl. ECVP, Fellow IATP
Q&A SESSION: To ask a question, click the Q&A
Button, type your question and click
send. Any questions that are not
addressed during the live webinar will
be answered following the event.
Thank you for participating!
Please contact Scintica Instrumentation for
additional information:
Phone: +1 (519) 914 5495
info@scinticainstrumentation.com