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[Is perfusion MRI feasible in lesions with disrupted blood-brain barrier? Pitfalls and possible solutions]
S Heiland1, M Hartmann, K Sartor
1Abteilung Neuroradiologie, Universitätsklinikum Heidelberg. Sabine_Heiland@med.uni-heidelberg.de
Aim:
When using perfusion-weighted magnetic resonance imaging (MRI) in lesions with blood-brain barrier (BBB) disruption two methods are normally applied to eliminate the influence of contrast material uptake on T2* dynamics: injection of contrast agent before starting perfusion imaging (pre-injection) and simultaneous acquisition of T1- and T2*-dynamics using a dual echo (DE)-FLASH sequence. The purpose of this study was to examine both methods with regard to their reliability.
Material And Methods:
We performed four perfusion measurements in a patient with a primary cerebral lymphoma located in the corpus callosum: two measurements with a DE-FLASH sequence and two measurements with a gradient-echo echo-planar-imaging (GE-EPI) sequence, respectively. In both cases there was one measurement with and one without pre-injection of contrast material.
Results:
Pre-injection of contrast material reduced the influence of T1 and allowed us to monitor the transient signal drop when using the GE-EPI sequence. Analysis of the time-course of DE-FLASH, however, showed that there was still a T1 decrease even after pre-injection. After the first pass the T2*-dynamics showed a distinct long-term T2*-decrease.
Discussion:
Neither pre-injection nor DE-FLASH allow us to eliminate the effects of contrast agent uptake completely. Both methods, however, increase the reliability of perfusion MRI. Their efficacy depends on the extent of the BBB disruption.
Insights
Neither pre-injection nor dual echo-FLASH perfusion MRI reliably eliminate contrast agent effects in disrupted blood-brain barrier lesions. Both methods improve perfusion MRI reliability, with efficacy varying by blood-brain barrier disruption extent.
Area of Science:
- Neuroimaging
- Radiology
- Medical Physics
Background:
- Perfusion-weighted MRI is crucial for evaluating lesions with blood-brain barrier (BBB) disruption.
- Standard methods to mitigate contrast agent effects include pre-injection and dual echo (DE)-FLASH sequences.
- Reliability of these methods in complex scenarios requires further investigation.
Observation:
- Gradient-echo echo-planar-imaging (GE-EPI) with pre-injection reduced T1 influence but still showed T1 decrease.
- DE-FLASH sequences exhibited persistent T1 decrease even after pre-injection.
- T2*-dynamics demonstrated a significant long-term decrease post-contrast first pass.
Findings:
- Complete elimination of contrast agent uptake effects was not achieved by either pre-injection or DE-FLASH.
- Both techniques enhance the reliability of perfusion MRI assessments.
- The effectiveness of these methods is contingent upon the degree of BBB disruption.
Implications:
- Clinical interpretation of perfusion MRI in BBB-disrupted lesions requires careful consideration of residual contrast effects.
- Further refinement of MRI techniques may be needed for precise quantification in these pathologies.
- Understanding these limitations is vital for accurate diagnosis and treatment monitoring.