Related Experiment Videos
Monitoring radiation-induced changes in bone marrow histopathology with ultra-small superparamagnetic iron oxide
H E Daldrup1, T M Link, S Blasius
1Institute of Clinical Radiology, University of Münster, Germany. daldruh@uni-muenster.de
Abstract:
The purpose of this study was to monitor radiation-induced alterations of the blood-bone marrow barrier (BMB) and the reticuloendothelial system (RES) with AMI-227-enhanced magnetic resonance imaging (MRI). Twenty New Zealand white rabbits (n = 10 following total body irradiation and n = 10 controls) underwent AMI-227-enhanced MRI. Pulse sequences included dynamic fast low-angle shot (FLASH; TR/TE 50/4 msec, flip angle 60 degrees) MRI and static T1- and T2-weighted spin-echo (SE) and turbo-SE sequences of the lumbar spine and sacrum. Bone marrow enhancement was quantified as delta signal intensity (SI) (%) =|[(SIpost - SIpre)/SIpre] x 100%| and compared with histopathology, including iron stains and electron microscopy. Dynamic bone marrow deltaSI (%) data steadily increased up to 10-15 minutes after AMI-227 administration, while blood deltaSI (%) data stayed nearly constant, histologically corresponding to iron oxide leakage into the bone marrow interstitium. This bone marrow contrast enhancement increased significantly following irradiation, corresponding to alterations of the endothelial lining of the bone marrow sinusoids. Late postcontrast images exhibited a significant positive T1 enhancement and negative T2 enhancement of the normal bone marrow, which further increased with irradiation due to increased RES activity. Irradiation-induced changes in bone marrow physiology could be reliably assessed with AMI-227-enhanced MRI.
Insights
Magnetic resonance imaging (MRI) with AMI-227 effectively monitors radiation effects on the blood-bone marrow barrier and reticuloendothelial system. This technique reveals irradiation-induced changes in bone marrow physiology and increased RES activity.
Area of Science:
- Biomedical Imaging
- Radiology
- Hematology
Background:
- The blood-bone marrow barrier (BMB) and reticuloendothelial system (RES) are crucial for bone marrow homeostasis.
- Radiation exposure can significantly disrupt BMB and RES function.
- Non-invasive imaging methods are needed to assess these radiation-induced alterations.
Purpose of the Study:
- To evaluate the utility of AMI-227-enhanced magnetic resonance imaging (MRI) for monitoring radiation-induced changes in the BMB and RES.
- To correlate MRI findings with histopathological assessments of bone marrow.
Main Methods:
- Twenty New Zealand white rabbits underwent total body irradiation (n=10) or served as controls (n=10).
- AMI-227-enhanced MRI was performed using dynamic fast low-angle shot (FLASH) and static T1/T2-weighted spin-echo sequences.
- Bone marrow enhancement was quantified, and results were compared with iron stains and electron microscopy.
Main Results:
- AMI-227 demonstrated increased bone marrow enhancement post-irradiation, indicating iron oxide leakage and BMB disruption.
- Dynamic MRI showed increased bone marrow delta signal intensity (SI) after AMI-227 administration.
- Irradiation led to significant increases in bone marrow contrast enhancement and altered T1/T2 signal intensities, reflecting increased RES activity.
Conclusions:
- AMI-227-enhanced MRI reliably assesses radiation-induced alterations in bone marrow physiology.
- The technique effectively visualizes changes in the BMB and RES following irradiation.
- This imaging approach offers a valuable tool for studying radiation effects on bone marrow.