Tracer Delay Correction of Cerebral Blood Flow with Dynamic Susceptibility Contrast-Enhanced MRI

Ibaraki, Masanobu; Shimosegawa, Eku; Toyoshima, Hideto; Takahashi, Kazuhiro; Miura, Shuichi; Kanno, Iwao

doi:10.1038/sj.jcbfm.9600037

Cited by 52 publications

(51 citation statements)

References 27 publications

(46 reference statements)

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“…Consistent with a previous simulation, 15 there was a very good linear correlation between the 2 methods for CBF, MTT, and MTT delay (Figure 1), but as expected, the sSVD method substantially overestimated long MTT and MMT delays, ie, in the ischemic range, consistent with previous reports. 19,20 Thus, methods to control for delay should be recommended in acute stroke to avoid overestimating the area with hemodynamic compromise. Nevertheless, to allow meaningful comparison with current clinical literature, we opted to present and discuss mainly the results obtained with sSVD.…”

Section: Discussionmentioning

confidence: 99%

How Reliable Is Perfusion MR in Acute Stroke?

Takasawa

Jones

Guadagno

et al. 2008

Stroke

180

112

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Background and Purpose-Perfusion magnetic resonance imaging (pMR) is increasingly used in acute stroke, but its physiologic significance is still debated. A reasonably good correlation between pMR and positron emission tomography (PET) has been reported in normal subjects and chronic cerebrovascular disease, but corresponding validation in acute stroke is still lacking. Methods-We compared the cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) maps generated by pMR (deconvolution method) and PET ( 15 O steady-state method) in 5 patients studied back-to-back with the 2 modalities at a mean of 16 hours (range, 7 to 21 hours) after stroke onset. We also determined the penumbra thresholds for pMR-derived MTT, time to peak (TTP), and Tmax against the previously validated probabilistic PET penumbra thresholds. Results-In all patients, the PET and pMR relative distribution images were remarkably similar, especially for CBF and MTT. Within-patient correlations between pMR and PET were strong for absolute CBF (average r 2 ϭ0.45) and good for MTT (r 2 ϭ0.35) but less robust for cerebral blood volume (r 2 ϭ0.24). However, pMR overestimated absolute CBF and underestimated MTT, with substantial variability in individual slopes. Removing individual differences by normalization to the mean resulted in much stronger between-patient correlations. Penumbra thresholds of Ϸ6, 4.8, and 5.5 seconds were obtained for MTT delay, TTP delay, and Tmax, respectively. Conclusions-Although derived from a small sample studied relatively late after stroke onset, our data show that pMR tends to overestimate absolute CBF and underestimate MTT, but the relative distribution of the perfusion variables was remarkably similar between pMR and PET. pMR appears sufficiently reliable for clinical purposes and affords reliable detection of the penumbra from normalized time-based thresholds. (Stroke. 2008;39:870-877.)

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Section: Discussionmentioning

confidence: 99%

How Reliable Is Perfusion MR in Acute Stroke?

Takasawa

Jones

Guadagno

et al. 2008

Stroke

180

112

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“…2,10 Regional tracer delay, which frequently occurs in patients with ischemic cerebrovascular disease, introduces errors into CBF and MTT estimates; consequently, delineation of the tissue with abnormal perfusion is aŠected. [11][12][13][14] Regional diŠerences in tracer arrival time have also been reported in normal brains. 5,[15][16][17] Although regional tracer delay in the normal brain is expected to be small, at less than a few seconds, simulation studies have shown that a small delay can cause a large error in SVD-CBF for tissue with a relatively short MTT.…”

Section: Introductionmentioning

confidence: 92%

Effect of Regional Tracer Delay on CBF in Healthy Subjects Measured with Dynamic Susceptibility Contrast-Enhanced MRI: Comparison with 15O-PET

et al. 2005

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Purpose: Deconvolution based on truncated singular value decomposition (SVD deconvolution) is a promising method for measuring cerebral blood ‰ow (CBF) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI), but it has proved extremely sensitive to tracer delay. The purpose of this study was to investigate the eŠect of regional tracer delay on CBF determined by SVD deconvolution (SVD-CBF). SVD-CBFs with and without correction for the delay were compared with CBF measured by positron emission tomography (PET-CBF), which is regarded as the gold standard for quantiˆcation of CBF.Methods: Perfusion MRI and PET were performed on seven healthy men. In the PET study, the CBF image was obtained with bolus injection of H 2 15 O and continuous arterial sampling. In the DSC-MRI study with bolus injection of Gd-based contrast agent, dynamic perfusion data were obtained with a 1.5T scanner at 1-s intervals by means of gradientecho echo-planar imaging. CBF was determined by the SVD deconvolution method with and without correction for the tracer delay. Region-of-interest measurements were obtained in the gray matter (cerebral cortex in the middle cerebral artery territory) and white matter (centrum semiovale).Results: Tracer delay was signiˆcantly longer in white matter than in gray matter (1.45± 0.61 s vs. 0.59±0.35 s, Pº0.01). Correction for the delay increased SVD-CBF in the white matter and consequently reduced the gray-to-white SVD-CBF ratio. The uncorrected grayto-white SVD-CBF ratio was signiˆcantly larger than that of Pº0.01). However, the gray-to-white delay-corrected SVD-CBF ratio did not diŠer signiˆcantly from that of PET-CBF (2.83±0.31 vs. 2.54±0.49, P＝0.10).Conclusion: The tracer delay in DSC-MRI causes errors in CBF estimates, even in healthy persons, and therefore should be corrected for when delay-sensitive deconvolution, such as SVD deconvolution, is used.

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“…The sSVD technique is widely used for the quantitative evaluation of MTT and CBF; however, it is known to be susceptible to the delay in the arrival of contrast materials to the brain tissue, leading to a miscalculation of MTT and CBF. 12,13 Algorithms that compensate for the delayed arrival time of the tracer 12 and those that are inherently insensitive to tracer delay have already been proposed, such as bSVD 6 and fast Fourier transform 13 to overcome this issue. On the other hand, few studies concerning CTP have focused on deconvolution algorithms.…”

Section: Discussionmentioning

confidence: 99%

“…Nonetheless, several reports on DSC-MR imaging have stated that tracer-arrival delay can result in the overestimation of MTT prolongation and CBF reduction and that its compensation can correct this error. [11][12][13][14] In the field of DSC-MR imaging, deconvolution algorithms for the intravascular tracer model have been thoroughly investigated. The sSVD technique is widely used for the quantitative evaluation of MTT and CBF; however, it is known to be susceptible to the delay in the arrival of contrast materials to the brain tissue, leading to a miscalculation of MTT and CBF.…”

Section: Discussionmentioning

confidence: 99%

Tracer Delay–Insensitive Algorithm Can Improve Reliability of CT Perfusion Imaging for Cerebrovascular Steno-Occlusive Disease: Comparison with Quantitative Single-Photon Emission CT

Sasaki¹,

Kudo²,

Ogasawara³

et al. 2008

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE:Reliability of CT perfusion (CTP) algorithms has not been fully validated. We investigated whether the cerebral blood flow (CBF) values obtained by using a dynamic CTP technique with a tracer delay-insensitive deconvolution algorithm are more accurate than those obtained by using CTP with delay-sensitive algorithms in unilateral cerebrovascular steno-occlusive disease, when compared with those generated by quantitative single-photon emission CT (SPECT).

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Tracer Delay Correction of Cerebral Blood Flow with Dynamic Susceptibility Contrast-Enhanced MRI

Cited by 52 publications

References 27 publications

How Reliable Is Perfusion MR in Acute Stroke?

How Reliable Is Perfusion MR in Acute Stroke?

Effect of Regional Tracer Delay on CBF in Healthy Subjects Measured with Dynamic Susceptibility Contrast-Enhanced MRI: Comparison with 15O-PET

Tracer Delay–Insensitive Algorithm Can Improve Reliability of CT Perfusion Imaging for Cerebrovascular Steno-Occlusive Disease: Comparison with Quantitative Single-Photon Emission CT

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