On the scope and interpretation of the Tofts models for DCE‐MRI

Sourbron, Steven; Buckley, David L.

doi:10.1002/mrm.22861

Cited by 319 publications

(339 citation statements)

References 41 publications

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“…Second, estimations of v p from the extended Tofts model may be unstable or insensitive to small v p changes due to model over-fitting or water exchange effects reducing the first-pass amplitude of T 1 -weighted DCE data. 26 The association between R Ã 2 , tumor hypoxia and blood flow is also supported by previous literature, 27,28 although their different MR data acquisition and analysis cannot be directly related to our parameter, R Ã 2 -peak enh . To further investigate our hypothesis and elucidate the exact mechanism behind the associations between low R Ã 2 -peak enh , low K trans and lymph node metastasis, supplementary studies are required.…”

Section: Discussionsupporting

confidence: 87%

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Grøvik

Redalen

Storås

et al. 2016

J. Magn. Reson. Imaging

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Purpose: To implement a dynamic contrast-based multi-echo MRI sequence in assessment of rectal cancer and evaluate associations between histopathologic data and the acquired dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) -MRI parameters. Materials and Methods: This pilot study reports results from 17 patients with resectable rectal cancer. Dynamic contrast-based multi-echo MRI (1.5T) was acquired using a three-dimensional multi-shot EPI sequence, yielding both DCE-and DSC-data following a single injection of contrast agent. The Institutional Review Board approved the study and all patients provided written informed consent. Quantitative analysis was performed by pharmacokinetic modeling on DCE data and tracer kinetic modeling on DSC data. Mann-Whitney U-test and receiver operating characteristics curve statistics was used to evaluate associations between histopathologic data and the acquired DCE-and DSC-MRI parameters. Results: For patients with histologically confirmed nodal metastasis, the primary tumor demonstrated a significantly lower K trans and peak change in R Ã 2 , R Ã 2 -peak enh , than patients without nodal metastasis, showing a P-value of 0.010 and 0.005 for reader 1, and 0.043 and 0.019 for reader 2, respectively. Conclusion: This study shows the feasibility of acquiring DCE-and DSC-MRI in rectal cancer by dynamic multi-echo MRI. A significant association was found between both K trans and R Ã 2 -peak enh in the primary tumor and histological nodal status of the surgical specimen, which may improve stratification of patients to intensified multimodal treatment.

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Section: Discussionsupporting

confidence: 87%

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Grøvik

Redalen

Storås

et al. 2016

J. Magn. Reson. Imaging

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“…TM produces reliable results only when the tissue is weakly vascularized, whereas the ETM can also be applied to highly perfused tumors [22]. The contrast agent leaves the plasma space and enters the EES at a rate represented by k trans and returns by k ep = k trans /v e , which is the exchange rate from EES to the plasma space where v e is the volume of EES.…”

Section: Pharmacokinetic Model Approachmentioning

confidence: 99%

Pattern recognition and pharmacokinetic methods on DCE-MRI data for tumor hypoxia mapping in sarcoma

Venianaki

Salvetti

Bree

et al. 2017

Multimed Tools Appl

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The main purpose of this study is to analyze the intrinsic tumor physiologic characteristics in patients with sarcoma through model-free analysis of dynamic contrast enhanced MR imaging data (DCE-MRI). Clinical data were collected from three patients with two different types of histologically proven sarcomas who underwent conventional and advanced MRI examination prior to excision. An advanced matrix factorization algorithm has been applied to the data, resulting in the identification of the principal time-signal uptake Multimed Tools Appl (2018) curves of DCE-MRI data, which were used to characterize the physiology of the tumor area, described by three different perfusion patterns i.e. hypoxic, well-perfused and necrotic one. The performance of the algorithm was tested by applying different initialization approaches with subsequent comparison of their results. The algorithm was proven to be robust and led to the consistent segmentation of the tumor area in three regions of different perfusion, i.e. wellperfused, hypoxic and necrotic. Results from the model-free approach were compared with a widely used pharmacokinetic (PK) model revealing significant correlations.

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“…Because the blood signal can contribute significantly to the timeactivity curve, each model can include a blood volume fraction term, v b (adding 1 C p v b to the model). This term has been shown to improve kinetic models for highly perfused tissues (22). Models with and without a v b term will be compared.…”

Section: Model Selectionmentioning

confidence: 99%

Determination of an Optimal Pharmacokinetic Model of ¹⁸F-FET for Quantitative Applications in Rat Brain Tumors

et al. 2017

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O-(2-18 F-fluoroethyl)-L-tyrosine ( 18 F-FET) is a radiolabeled artificial amino acid used in PET for tumor delineation and grading. The present study compares different kinetic models to determine which are more appropriate for 18 F-FET in rats. Methods: Rats were implanted with F98 glioblastoma cells in the right hemisphere and scanned 9-15 d later. PET data were acquired during 50 min after a 1-min bolus of 18 F-FET. Arterial blood samples were drawn for arterial input function determination. Two compartmental pharmacokinetic models were tested: the 2-tissue model and the 1-tissue model. Their performance at fitting concentration curves from regions of interest was evaluated using the Akaike information criterion, F test, and residual plots. Graphical models were assessed qualitatively. Results: Metrics indicated that the 2-tissue model was superior to the 1-tissue model for the current dataset. The 2-tissue model allowed adequate decoupling of 18 F-FET perfusion and internalization by cells in the different regions of interest. Of the 2 graphical models tested, the Patlak plot provided adequate results for the tumor and brain, whereas the Logan plot was appropriate for muscles. Conclusion: The 2-tissue-compartment model is appropriate to quantify the perfusion and internalization of 18 F-FET by cells in various tissues of the rat, whereas graphical models provide a global measure of uptake. Ther adiolabeled artificial amino acid O-(2-18 F-fluoroethyl)-Ltyrosine ( 18 F-FET) has proven useful for the PET assessment of brain tumors in preclinical and clinical settings (1-3). Its high uptake in tumor tissue compared with normal brain and inflamed tissues allows for efficient tumor delineation (4), but the typical SUVs and tumor-to-brain ratios are of limited use for tumor grading (5,6). In contrast, the shape of time-activity curves are indicative of tumor grade and aggressiveness (7). For example, in untreated or recurring gliomas, continuously ascending curves are associated with a better prognosis than curves that reach a maximum a few minutes after injection (6,8), but the underlying mechanisms remain to be clarified (7,9,10). A pharmacokinetic model could help explain these differences and would allow quantitative comparison of cohorts.There have been few reports on 18 F-FET pharmacokinetic modeling (11,12), and a consensus on the most appropriate models has not been proposed. The present study aims at identifying the best models in different tissue types. MATERIALS AND METHODS Animal ModelExperiments were conducted in accordance with the recommendations of the Canadian Council on Animal Care and the local Ethics Committee. F98 glioblastoma cells were implanted in the right hemisphere of 17 male Fischer rats (254.6 6 15.9 g, Charles River Laboratories) according to a previously published protocol (13). The animals underwent dynamic PET scans 9-15 d after implantation. All imaging procedures were performed under isoflurane anesthesia with breathing rate and temperature continuously monitored. An automatic in...

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On the scope and interpretation of the Tofts models for DCE‐MRI

Cited by 319 publications

References 41 publications

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Pattern recognition and pharmacokinetic methods on DCE-MRI data for tumor hypoxia mapping in sarcoma

Determination of an Optimal Pharmacokinetic Model of ¹⁸F-FET for Quantitative Applications in Rat Brain Tumors

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On the scope and interpretation of the Tofts models for DCE‐MRI

Cited by 319 publications

References 41 publications

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor Ktrans and ΔR2* peak are significantly associated with lymph node metastasis

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor Ktrans and ΔR2* peak are significantly associated with lymph node metastasis

Pattern recognition and pharmacokinetic methods on DCE-MRI data for tumor hypoxia mapping in sarcoma

Determination of an Optimal Pharmacokinetic Model of 18F-FET for Quantitative Applications in Rat Brain Tumors

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Product

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About

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Determination of an Optimal Pharmacokinetic Model of ¹⁸F-FET for Quantitative Applications in Rat Brain Tumors