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Assessment of cerebral blood volume with dynamic susceptibility contrast enhanced gradient-echo imaging
1Institut für Klinische Radiologie, Klinikum Mannheim, Klinische Fakultät II, Universität Heidelberg, Germany.
Objective:
Dynamic susceptibility contrast (DSC) enhanced MRI was used to study relative cerebral blood volume (rCBV).
Materials And Methods:
We examined 15 healthy subjects and 47 patients with vascular stenosis or occlusion, with brain infarctions, and with cerebral neoplasms. During bolus injection of Gd-diethylenetriamine pentaacetic acid, a series of rapid T2*-weighted fast low angle shot two-dimensional images were recorded from the same slice. From these images, changes in signal intensity during bolus passage were computed pixel-by-pixel and converted into contrast agent concentration curves. Applying the principles of indicator dilution theory, images of rCBV were calculated.
Results And Conclusion:
Regions of infarctions show almost zero rCBV. In patients with high-grade vascular stenosis or occlusion a bolus delay in comparison to the unaffected side and an increased mean transit time can be observed. Some of the affected areas show an increased rCBV, which is a well-known physiological mechanism that takes place to compensate for the reduced cerebral blood pressure. In brain tumors, rCBV imaging reveals focal or homogeneous areas of increased blood volume. This can even be observed in low-grade astrocytomas with unaffected blood-brain barrier. In CBV imaging, the effects of radiotherapy on tumor tissue can be monitored as a significant decrease of rCBV in tumor tissue after therapy.
Insights
Dynamic susceptibility contrast MRI quantifies relative cerebral blood volume (rCBV) in various brain conditions. This imaging technique reveals zero rCBV in infarctions and increased rCBV in tumors and areas compensating for reduced blood pressure.
Area of Science:
- Neuroradiology
- Cerebrovascular Imaging
- Medical Imaging
Background:
- Dynamic susceptibility contrast (DSC) enhanced MRI is a key technique for assessing cerebral hemodynamics.
- Relative cerebral blood volume (rCBV) is a critical parameter reflecting blood supply in the brain.
Purpose of the Study:
- To investigate the utility of DSC-MRI for quantifying rCBV in patients with cerebrovascular diseases and neoplasms.
- To correlate rCBV changes with specific pathologies like infarction, stenosis, occlusion, and brain tumors.
Main Methods:
- Utilized DSC-MRI with Gd-diethylenetriamine pentaacetic acid bolus injection in 15 healthy subjects and 47 patients.
- Acquired rapid T2*-weighted fast low angle shot 2D images to track contrast agent passage.
- Applied indicator dilution theory for pixel-by-pixel calculation of rCBV maps.
Main Results:
- Infarcted regions demonstrated near-zero rCBV.
- Patients with high-grade stenosis/occlusion showed delayed bolus transit and increased mean transit time.
- Brain tumors, including low-grade astrocytomas, exhibited focal or homogeneous increases in rCBV.
- Radiotherapy effects on tumor tissue were monitored via significant rCBV decrease post-treatment.
Conclusions:
- DSC-MRI-derived rCBV is effective in characterizing hemodynamic changes in infarction, stenosis, and occlusion.
- rCBV imaging aids in the detection and monitoring of brain tumors and their response to therapy.
- This technique provides valuable insights into compensatory mechanisms in reduced cerebral perfusion.