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Reliability of mean transit time obtained using perfusion-weighted MR imaging; comparison with positron emission
Futoshi Mihara1, Yasuo Kuwabara, Atsuo Tanaka
1Department of Clinical Radiology, Kyushu University, Fukuoka, Japan. fmihara@radiol.med.kyushu-u.ac.jp
Abstract:
The purpose of this project was to assess the reliability of the cerebral mean transit time (MTT) obtained using perfusion-weighted MR imaging by comparing it with the MTT obtained when performing positron emission tomography (PET). Ten patients with chronic occlusive cerebrovascular disease were investigated. They had either unilateral internal carotid artery occlusion or middle cerebral artery occlusion. The regions-of-interest were placed in non-infarcted areas within the territory of the middle cerebral artery on the affected side. Control regions-of-interest were placed in mirrored regions of the contralateral side. Linear regression analyses were performed using the parameters of the MTT obtained with perfusion-weighted MR imaging and the MTT, cerebral blood flow, vascular reactivity, and oxygen extraction fraction obtained with PET. The respective MTTs of the affected and non-affected sides obtained with perfusion-weighted MR imaging versus those with PET were 7.3 +/- 2.2 s and 6.0 +/- 1.2 s versus 8.2 +/- 3.0 s and 6.4 +/- 1.7 s. The MTT obtained using perfusion-weighted MR imaging and PET demonstrated statistically significant correlation (r = 0.87, p < 0.0001). The MTT obtained with perfusion-weighted MR imaging correlated statistically with cerebral blood flow (r = -0.74, p < 0.001), vascular reactivity (r = -0.73, p < 0.001) and oxygen extraction fraction (r = 0.61, p < 0.01). Similarly, the MTT obtained using PET statistically correlated with cerebral blood flow (r = -0.78, p < 0.0001), vascular reactivity (r = -0.51, p < 0.05) and oxygen extraction fraction (r = 0.68, p < 0.01). The reliability of the MTT obtained using perfusion-weighted MR imaging appears to be approximately equal to that obtained with positron emission tomography.
Insights
Perfusion-weighted MR imaging reliably measures cerebral mean transit time (MTT), comparable to positron emission tomography (PET) in patients with cerebrovascular disease.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Cerebral mean transit time (MTT) is a crucial parameter for assessing cerebrovascular health.
- Positron emission tomography (PET) is a gold standard for measuring MTT, but it involves radiation exposure.
- Perfusion-weighted MR imaging offers a non-invasive alternative for evaluating cerebral blood flow dynamics.
Purpose of the Study:
- To evaluate the reliability of cerebral mean transit time (MTT) measurements using perfusion-weighted MR imaging.
- To compare MTT values obtained from MR imaging with those from positron emission tomography (PET) in patients with chronic occlusive cerebrovascular disease.
Main Methods:
- Ten patients with unilateral internal carotid artery or middle cerebral artery occlusion were studied.
- Regions of interest were placed in affected and contralateral non-infarcted middle cerebral artery territories.
- Linear regression analysis compared MTT from MR imaging with MTT, cerebral blood flow, vascular reactivity, and oxygen extraction fraction from PET.
Main Results:
- MTT values from MR imaging and PET showed a strong correlation (r = 0.87, p < 0.0001).
- MR imaging-derived MTT correlated significantly with PET-derived cerebral blood flow (r = -0.74), vascular reactivity (r = -0.73), and oxygen extraction fraction (r = 0.61).
- PET-derived parameters also showed significant correlations with MTT, supporting the validity of MR imaging findings.
Conclusions:
- Perfusion-weighted MR imaging provides reliable MTT measurements in patients with cerebrovascular disease.
- The reliability of MR imaging for MTT assessment is comparable to that of PET.
- MR imaging represents a promising non-invasive tool for evaluating cerebral hemodynamics.