Perfusion-Weighted Magnetic Resonance Imaging Thresholds Identifying Core, Irreversibly Infarcted Tissue

Shih, Ludy C.; Saver, Jeffrey L.; Alger, Jeffry R.; Starkman, Sidney; Leary, Megan; Viñuela, Fernando; Duckwiler, Gary; Gobin, Y. Pierre; Jahan, Reza; Villablanca, J. Pablo; Vespa, Paul; Kidwell, Chelsea S.

doi:10.1161/01.str.0000072998.70087.e9

Cited by 178 publications

(142 citation statements)

References 23 publications

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“…These data can be compared with a previous volumetric analysis of TTP maps that found a higher sensitivity (84%) but a lower specificity (77%) for a relative TTP prolongation of Ն4 seconds 12 and are in line with previous outcome-based MRI studies of TTP maps. 8,46,47 The C-ratio, however, only reflected the median value of our data. On an individual level, it showed a considerable variation in our sample.…”

Section: Zaro-weber Et Al Mri-cbf In Acute Stroke Compared With H 2 Ocontrasting

confidence: 70%

The Performance of MRI-Based Cerebral Blood Flow Measurements in Acute and Subacute Stroke Compared With 15O-Water Positron Emission Tomography

Zaro-Weber

Moeller-Hartmann

Heiss

et al. 2009

Stroke

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Background and Purpose-Perfusion-weighted MRI-based maps of cerebral blood flow (CBF MRI ) are considered a good MRI measure of penumbral flow in acute ischemic stroke but are seldom used in clinical routine due to methodical issues. We validated CBF MRI on quantitative CBF measurement by 15O-water positron emission tomography (CBF PET ). Material and Methods-Comparative CBF MRI and CBF PET were performed in patients with acute and subacute stroke. In a voxel-based seed-growing technique, predefined CBF MRI thresholds (Ͻ40, Ͻ30, Ͻ20, Ͻ10 mL/100 g/min) were applied and the resulting volumes were compared with the hypoperfusion volume detected by the penumbral threshold (Ͻ20 mL/100 g/min) on CBF PET . The volumetric comparison was expressed as the C-ratio (volume CBF MRI /volume CBF PET ) to identify the best MRI threshold. The influence of vessel pathology, hypoperfusion size, and time point of imaging was described. The proportion of voxels correctly classified as hypoperfused and the proportion of voxel correctly classified as nonhypoperfused of the best CBF MRI threshold was calculated and a Bland-Altman plot illustrated the method-specific differences. Results-In 24 patients (median time MRI to PET: 68 minutes; 16 patients imaged within 24 hours after stroke), the median volume of hypoperfusion Ͻ20 mL/100 g/min (CBF PET ) was 78.5 cm 3 . Median hypoperfusion volume on CBF MRI ranged from 245.9 cm 3 (Ͻ40 mL/100 g/min) to 35.5 cm 3 (Ͻ10 mL/10 g/min). On visual inspection, an excellent qualitative congruence was found. The quantitative congruence was best for the MRI-CBF threshold Ͻ20 mL/100 g/min (median C-ratio: 1.0), reaching a proportion of voxels correctly classified as hypoperfused of 76% and a proportion of voxel correctly classified as nonhypoperfused of 96%, but a wide interindividual range (C-ratio 0.3 to 3.5) was found. Ipsilateral vessel pathology, time point of imaging, and size of hypoperfusion did not significantly influence the C-ratio. The Bland-Altman analysis for the volumetric difference of CBF MRI and CBF PET found a good overall agreement but a large SD. Conclusion-Hypoperfusion

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Section: Zaro-weber Et Al Mri-cbf In Acute Stroke Compared With H 2 Ocontrasting

confidence: 70%

The Performance of MRI-Based Cerebral Blood Flow Measurements in Acute and Subacute Stroke Compared With 15O-Water Positron Emission Tomography

Zaro-Weber

Moeller-Hartmann

Heiss

et al. 2009

Stroke

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“…Based on the deconvolved tissue curve (Fig. 3b), a delay of the occurrence of the peak value (the height of the curve, defining CBF) can be defined, sometimes referred to as T max (47). Although the dependence of these indices on MTT and CBF depends strongly on the vascular structure and the AIF (41), these indices often suffice to delineate pathological changes and provide important qualitative information in many diseases.…”

Section: Other Hemodynamic Indicesmentioning

confidence: 99%

Principles of cerebral perfusion imaging by bolus tracking

Østergaard

2005

Magnetic Resonance Imaging

248

215

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The principles of cerebral perfusion imaging by the method of dynamic susceptibility contrast magnetic resonance imaging (DSC‐MRI) (bolus tracking) are described. The MRI signals underlying DSC‐MRI are discussed. Tracer kinetics procedures are defined to calculate images of cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT). Two general categories of numerical procedures are reviewed for deriving CBF from the residue function. Procedures that involve deconvolution, such as Fourier deconvolution or singular value decomposition (SVD), are classified as model‐independent methods because they do not require a model of the microvascular hemodynamics. Those methods in principle also yield a measure of the tissue impulse response function and the residue function, from which microvascular hemodynamics can be characterized. The second category of methods is the model‐dependent methods, which use models of tracer transport and retention in the microvasculature. These methods do not yield independent measures of the residue function and may introduce bias when the physiology does not follow the model. Statistical methods are sometimes used, which involve treating the residue function as a deconvolution kernel and optimizing (fitting) the kernel from the experimental data using procedures such as maximum likelihood. Finally, other hemodynamic indices that can be measured from DSC‐MRI data are described. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.

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“…Articles in category 2 correlated perfusion imaging findings with clinical outcome, and those in category 3 compared perfusion imaging findings with final size of the infarct on subsequent imaging studies. 5,6,14,19,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] Articles in category 2 and category 3 served the dual functions of validating perfusion imaging as a test and providing information that could be used for prognosis but not use of perfusion imaging in decision making.…”

Section: Explanation Of Categories Of Articles With Use Of Perfusion mentioning

confidence: 99%

“…The 20 articles in this category are listed in on-line Table 2. 5,6,14,19,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] In aggregate, these articles suggest that hemodynamic parameters can show regions of brain tissue that are ischemic and likely to progress to infarction. Although this information helps one to understand the physiologic changes in ischemic tissue and may provide some insights into conversion of ischemic (and potentially salvageable) regions into infarcted tissue, this information is of limited use in deciding on treatment in individual cases.…”

Section: Representative Articles From Acute Cerebral Ischemia Perfusimentioning

confidence: 99%

Systematic Review of CT and MR Perfusion Imaging for Assessment of Acute Cerebrovascular Disease

Provenzale¹,

Shah²,

Patel³

et al. 2008

AJNR Am J Neuroradiol

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Perfusion-Weighted Magnetic Resonance Imaging Thresholds Identifying Core, Irreversibly Infarcted Tissue

Abstract: Perfusion-weighted imaging measures of ischemia severity accurately differentiate irreversibly injured core from penumbral, salvageable tissue. The best threshold for identifying core infarcted tissue is adjusted Tmax of > or =6 to 8 seconds.

Cited by 178 publications

References 23 publications

The Performance of MRI-Based Cerebral Blood Flow Measurements in Acute and Subacute Stroke Compared With 15O-Water Positron Emission Tomography

The Performance of MRI-Based Cerebral Blood Flow Measurements in Acute and Subacute Stroke Compared With 15O-Water Positron Emission Tomography

Principles of cerebral perfusion imaging by bolus tracking

Systematic Review of CT and MR Perfusion Imaging for Assessment of Acute Cerebrovascular Disease

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