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Regional relative blood volume MR maps of meningiomas before and after partial embolization
R Bruening1, R H Wu, T A Yousry
1Institute of Diagnostic Radiology, Klinikum Grosshadern, Ludwig Maximilian University of Munich, Germany.
Purpose:
Our goal was to evaluate the role of relative blood volume (rBV) measurements in monitoring the embolization effect in meningiomas by using maps of susceptibility-weighted first pass MR data.
Method:
Eighteen examinations of nine patients before and following partial embolization were performed on a 1.5 T scanner. Embolization was achieved by injection of particles (45-150 microns). During dynamic imaging a bolus (0.2 mmol/kg) of gadopentetate dimeglumine was injected.
Results:
The tumor rBV/gray matter rBV ratio was 3.11 +/- 1.40 for untreated tumors and 0.12 +/- 0.09 for successfully embolized tumors. The regional rBV in embolized meningiomas was significantly lower than that in untreated meningiomas (t test, p < 0.001). Vital tumor tissue showed positive enhancement in T1 and high rBV; nonvital tissue lacked T1 enhancement and bolus effect in the first pass, thus leading to low or missing rBV values. However, we also observed lack of bolus formation despite T1 enhancement (6/9 postembolization regions), possibly due to slow collateral flow. One of the patients treated with embolization bled during surgery.
Conclusion:
Maps of relative regional cerebral BV provide hemodynamic information in meningiomas and monitor the treatment effect of embolization in meningiomas more precisely than T1-weighted contrast-enhanced imaging.
Insights
Relative blood volume (rBV) measurements effectively monitor meningioma embolization. Post-treatment, rBV significantly decreases, indicating successful reduction of tumor blood supply and providing precise hemodynamic insights.
Area of Science:
- Neuroradiology
- Medical Imaging
- Neurosurgery
Background:
- Meningiomas are common primary brain tumors.
- Embolization is a therapeutic option for meningiomas.
- Monitoring treatment effectiveness is crucial for patient outcomes.
Purpose of the Study:
- To assess the utility of relative blood volume (rBV) mapping using susceptibility-weighted first-pass MR data.
- To evaluate rBV as a tool for monitoring the embolization effect in meningiomas.
Main Methods:
- Nine patients with meningiomas underwent 18 MRI examinations before and after embolization.
- Embolization involved injecting particles (45-150 microns).
- Dynamic imaging utilized a gadopentetate dimeglumine bolus (0.2 mmol/kg) on a 1.5 T scanner.
Main Results:
- The tumor rBV/gray matter rBV ratio decreased from 3.11 ± 1.40 (untreated) to 0.12 ± 0.09 (embolized) (p < 0.001).
- Vital tumor tissue showed high rBV and T1 enhancement; nonvital tissue had low/absent rBV and lacked T1 enhancement.
- Slow collateral flow sometimes resulted in absent bolus formation despite T1 enhancement.
Conclusions:
- Relative regional cerebral blood volume (rBV) maps offer valuable hemodynamic information for meningiomas.
- rBV mapping provides more precise monitoring of embolization treatment effects compared to T1-weighted contrast-enhanced imaging.