Correlative assessment of hemodynamic parameters obtained with T2*-weighted perfusion MR imaging and SPECT in
1Gyeongsang Institute for Neuroscience, Gyeongsang National University Hospital, Chinju, South Korea.
Insights
Uncorrected mean transit time (uMTT) from perfusion MR imaging better estimates vascular reserve capacity in cerebrovascular disease than other parameters. Comparing MR imaging and SPECT data is crucial for accurate hemodynamic assessment.
Area of Science:
- Neuroimaging
- Cerebrovascular Disease
- Hemodynamics
Background:
- Perfusion MR imaging and SPECT are vital for assessing hemodynamic status in symptomatic occlusive cerebrovascular disease.
- These techniques utilize different physiological mechanisms, potentially leading to data discrepancies.
- Understanding the relationship between their parameters is essential for accurate patient evaluation.
Purpose of the Study:
- To investigate the correlation between hemodynamic parameters derived from perfusion MR imaging and SPECT.
- To compare the sensitivity of different parameters in assessing vascular reserve capacity.
Main Methods:
- Perfusion MR imaging and SPECT were performed on 10 patients with symptomatic unilateral internal carotid artery occlusion.
- Key parameters measured included relative cerebral blood volume (rCBV), uncorrected mean transit time (uMTT), relative cerebral blood flow (rCBF), and vascular reserve capacity.
- Ratios of these parameters between affected and contralateral territories were calculated and compared.
Main Results:
- Affected territories showed normal-to-increased rCBV, prolonged uMTT, decreased rCBF, and normal-to-diminished vascular reserve capacity.
- Reduced vascular reserve capacity correlated well with prolonged uMTT.
- No significant correlation was found between rCBF, rCBV, and uMTT.
Conclusions:
- Uncorrected mean transit time (uMTT) demonstrates higher sensitivity in estimating vascular reserve capacity compared to other measured parameters.
- Clinical assessment of hemodynamic status in occlusive cerebrovascular disease requires careful consideration of the relationship between perfusion MR imaging and SPECT findings.
Background And Purpose:
Perfusion MR imaging and single-photon emission CT (SPECT) are commonly used to evaluate hemodynamic status in patients with symptomatic occlusive cerebrovascular disease. These techniques rely on different underlying physiological mechanisms, and the data may not correspond. We studied the relationship between hemodynamic parameters obtained with these two methods.
Methods:
We performed perfusion MR imaging and SPECT in 10 patients with symptomatic unilateral internal carotid artery occlusion. Relative cerebral blood volume (rCBV) and uncorrected mean transit time (uMTT) were obtained with dynamic contrast-enhanced T2*-weighted MR imaging. Relative cerebral blood flow (rCBF) and vascular reserve capacity were measured with 99mTc-HMPAO SPECT; vascular reserve capacity was calculated by the difference in CBF before and after acetazolamide challenge. Ratios of these hemodynamic parameters between the affected and contralateral vascular territories were calculated and compared.
Results:
Normal-to-increased CBV, prolonged uMTT, decreased CBF, and normal-to-diminished vascular reserve capacity were observed in the affected vascular territories. Reduction of vascular reserve capacity corresponded well with uMTT but not with CBF and CBV. CBF, CBV, and uMTT did not correspond to one another.
Conclusion:
uMTT is more sensitive than the other parameters in estimating vascular reserve capacity. The relationship between parameters obtained with perfusion MR imaging and SPECT should be considered in assessing the hemodynamic status of patients with symptomatic occlusive cerebrovascular disease.
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