The correlation between phase shifts in gradient-echo MR images and regional brain iron concentration

Ogg, Robert J.; Langston, J. William; Haacke, E. Mark; Steen, R. Grant; Taylor, Judy

doi:10.1016/s0730-725x(99)00017-x

Cited by 189 publications

(186 citation statements)

References 42 publications

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“…R2* and SWI with filter phase techniques have been used in brain iron quantification, usually in the basal ganglia and other deep gray matter nuclei (17,18,26). It is also known that dystrophic calcification is seen in a large number of individuals in the basal ganglia and contributes to both positive and negative phase (mixed phase) in these regions (24).…”

Section: Discussionmentioning

confidence: 99%

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Correlation of phase values with CT hounsfield and R2* values in calcified neurocysticercosis

Roy

Verma

Awasthi

et al. 2011

Magnetic Resonance Imaging

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Purpose: To correlate phase and R2* derived from susceptibility-weighted magnetic resonance imaging (MRI) with computed tomography-Hounsfield (CT-HU) values in calcified neurocysticercosis and to evaluate phase imaging in the assessment of calcified neurocysticercosis. Materials and Methods:Thirty-five patients with 52 calcified lesions underwent both CT and MRI. Phase and R2* were calculated from multi-echo 3D-T2-star-weighted-angiography data. MRI and CT data were coregistered using mutual information. Spearman's correlation was performed between quantitative phase and CT-HU and R2* values. The Mann-Whitney U-test was used to see differences between CT-HU and R2* values from corresponding positive and negative phase regions. Results:The median values of CT-HU and R2* from regions with positive and negative phase were found to be 142.10 (range: 41.89-491.75) and 68.5/sec (range: 20-110/sec) and 137.30 (range: 30.83-458.88) and 69/sec (range: 0-110/sec), respectively. There was a significant correlation of positive phase values with corresponding CT-HU and R2* values. In addition, there was a significant correlation of R2* and CT-HU with negative phase values. Conclusion:We conclude that there is a significant correlation between negative and positive phase with CT-HU and R2* values, suggesting that the CT hyperdense lesion may have both calcium and other minerals, which can be differentiated using phase imaging. Conventional MRI should include phase imaging to detect calcified neurocysticercosis.

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Section: Discussionmentioning

confidence: 99%

“…Quantitative phase imaging has been used to measure the brain iron content in healthy and diseased brain (13,14,17,18). In another study, the correlation of iron content with age in deep gray matter of healthy adults has also been shown (19).…”

mentioning

confidence: 99%

Correlation of phase values with CT hounsfield and R2* values in calcified neurocysticercosis

Roy

Verma

Awasthi

et al. 2011

Magnetic Resonance Imaging

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“…5. We used phase gap measurements corresponding to a minimum and maximum phase (defined as a phase gap) as a metrics that, we believe, reflects the level of iron concentration in GP (23,33). The results of these measurements averaged for left and right GP in PKAN patients and results of phase profile measurements in a healthy volunteer are summarized in Table 3.…”

Section: Phase Measurementsmentioning

confidence: 99%

“…We used phase gap changes across globus pallidus as a metric for iron concentration assessment (23). We demonstrate that the phase metrics exhibit a multifold increase in phase variations while magnitude methods demonstrated much smaller differentiation between healthy volunteers and PKAN patients.…”

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confidence: 99%

“…In a review article by Haacke et al the authors state that the phase of the MRI signal could be the most accurate MRI means to map iron content, while T1 and T2 relaxation times would play important yet complementary roles (22,23). This has already been demonstrated for gray matter / white matter contrast, small veins in the brain, and more recently in venous blood vessels in the peripheral vasculature (22,24).…”

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confidence: 99%

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Measurement of brain iron distribution in Hallevorden‐Spatz syndrome

Szumowski

Bas

Gaarder

et al. 2010

Magnetic Resonance Imaging

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Purpose: To investigate spatial distribution of iron accumulation in the globus pallidus (GP) in patients with Hallevorden-Spatz syndrome (HSS) using phase imaging. We compared sensitivity of a phase imaging technique to relaxation rate measurement methods (R1,R2,R2*) for iron quantification.Materials and Methods: R1, R2, and R2* were measured in GP structure of the brain of eight pantothenate kinaseassociated neurodegeneration (PKAN) patients and a healthy volunteer using a 3T magnetic resonance imaging (MRI) scanner. The phase of gradient-echo images was preprocessed to eliminate phase 2p wrapping and filtered to remove phase background variations. Phase gap across GP structure was used as a metric for iron effects quantification.Results: Among the relaxation rates the most sensitive to iron accumulation was the R2* rate. The R1 and R2 rates demonstrated only small variations in this group of subjects. Up to an order of magnitude phase gap changes were measured between one PKAN patient and an agematched healthy volunteer. Assuming that phase gap differences scale linearly with iron concentration we estimate that up to 2 mg Fe/g ww accumulates in GP of these patients.Conclusion: Our results demonstrate significantly higher sensitivity of the phase measurements for quantitative assessment of iron concentration compared to the relaxation rate measurements. Phase measurements could potentially be used for monitoring a progression and a response to therapy in PKAN.

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