Intratumor distribution and test–retest comparisons of physiological parameters quantified by dynamic contrast‐enhanced MRI in rat U251 glioma

Aryal, Madhava; Nagaraja, Tavarekere N.; Brown, Stephen L.; Lü, Mei; Bagher‐Ebadian, Hassan; Ding, Guangliang; Panda, Swayamprava; Keenan, Kelly A.; Cabral, Glauber; Mikkelsen, Tom; Ewing, James R.

doi:10.1002/nbm.3178

Cited by 21 publications

(35 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Double gradient echo sequences have also been used in other studies for T 2 * correction [17,24,25]. Multiple gradient echo sequences with more than two echoes may help to improve the T 2 * estimation accuracy further and to also reduce the sensitivity to the selected TE, as shown by Zhuo et al [26], although acquisition of multiple gradient echoes decreases the temporal resolution, which is not favorable for contrast kinetic model analysis in general.…”

Section: Discussionmentioning

confidence: 99%

Effect of $$ T_{2}^{*} $$ correction on contrast kinetic model analysis using a reference tissue arterial input function at 7 T

Jin

Freed

Winters

et al. 2015

Magn Reson Mater Phy

View full text Add to dashboard Cite

Object To investigate the effect of T2* correction on estimation of kinetic parameters from T1-weighted dynamic contrast enhanced (DCE) MRI data when a reference-tissue arterial input function (AIF) is used. Materials and Methods DCE-MRI data were acquired from 7 mice with 4T1 mouse mammary tumors using a double gradient echo sequence at 7T. The AIF was estimated from a region of interest in the muscle. The extended Tofts model was used to estimate pharmacokinetic parameters in the enhancing part of the tumor, with and without T2* correction of the lesion and AIF. The parameters estimated with T2* correction of both the AIF and lesion time-intensity curve were assumed to be the reference standard. Results For the whole population, there was significant difference (p<0.05) in transfer constant (Ktrans) between T2* corrected and not corrected methods, but not in interstitial volume fraction (ve). Individually, no significant differences were found in Ktrans and ve of four and six tumors, respectively, between the T2* corrected and not corrected methods. In contrast, Ktrans was significantly underestimated, if the T2* correction was not used, in other tumors of which median Ktrans was larger than 0.4 min−1. Conclusion T2* effect on tumors with high Ktrans may not be negligible in kinetic model analysis, even if AIF is estimated from reference tissue where the concentration of contrast agent is relatively low.

show abstract

Section: Discussionmentioning

confidence: 99%

Effect of $$ T_{2}^{*} $$ correction on contrast kinetic model analysis using a reference tissue arterial input function at 7 T

Jin

Freed

Winters

et al. 2015

Magn Reson Mater Phy

View full text Add to dashboard Cite

show abstract

“…The associated Pearson's r value and P value correspond to the colors of the solid lines. dynamic imaging on small-bore animal magnets (range: 6.3-9.4T) using a similar temporal resolution (range: 2-4.8 s) has spanned from 0.27 Â 0.27 Â 1.5 to 0.33 Â 0.33 Â 2.0 mm 3 (27,29,36,55). The similarity in acquisition parameters without sacrificing apparent image quality between the study described herein and investigations conducted at higher field strengths supports the assertion by Pillai et al that specialized coils may allow greater accessibility to animal-based MRI studies at centers without animal scanners (33).…”

Section: Discussionmentioning

confidence: 99%

A continuous‐infusion dynamic MRI model at 3.0 Tesla for the serial quantitative evaluation of microvascular proliferation in an animal model of glioblastoma multiforme

Underhill

2017

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose To develop a continuous-infusion dynamic MRI technique to characterize tumor-associated microvascular proliferation (MVP) in a rat brain model of glioblastoma multiforme. Theory and Methods The proposed model assumes effects due to tumor-associated MVP (e.g., vascular permeability, Ktrans; intravascular plasma fraction, vp) cannot be individually separated and solves for a single parameter (kvasc) that quantifies the T1-weighted contrast-enhancement from dynamic images acquired during continuous contrast agent (CA) infusion. Untreated C6 tumor-bearing animals (N=6) were serially imaged on post-op days (PODs) 14 and 18 with a 3T clinical scanner utilizing a dynamic spatial and temporal resolution of 0.38×0.38×1.5 mm3 and 3.47 s, respectively. Results An association was present between PODs 14 and 18 for median tumor kvasc (Pearson’s r=0.94, P=0.0052) and CA concentration ([CA], derived from pre- and post-contrast R1 maps; r=0.94, P=0.0054). On POD 18, there was a voxel-based association between kvasc and [CA] within each tumor (0.450.05) or an inverse association (N=1; r= −0.28, P=0.001) indicating differences between locations of vascular permeability and subsequent CA pooling in tumors. Conclusions The continuous-infusion method may provide a quantitative measure for characterizing and monitoring tumor-associated MVP.

show abstract

“…(31)] and Logan et al . analyses (25, 29, 30) of DCE-MRI data, using a model-selection paradigm (20–22) to estimate the plasma volume fraction (v p ), forward volumetric transfer constant (K trans ), interstitial volume fraction (v e ) and extracellular volume fraction (V D ); and 3. DWI to estimate ADC.…”

Section: Methodsmentioning

confidence: 99%

Acute Temporal Changes of MRI-Tracked Tumor Vascular Parameters after Combined Anti-angiogenic and Radiation Treatments in a Rat Glioma Model: Identifying Signatures of Synergism

et al. 2017

Self Cite

View full text Add to dashboard Cite

In this study we used magnetic resonance imaging (MRI) biomarkers to monitor the acute temporal changes in tumor vascular physiology with the aim of identifying the vascular signatures that predict response to combined anti-angiogenic and radiation treatments. Forty-three athymic rats implanted with orthotopic U-251 glioma cells were studied for approximately 21 days after implantation. Two MRI studies were performed on each animal, pre- and post-treatment, to measure tumor vascular parameters. Two animal groups received treatment comprised of Cilengitide, an anti-angiogenic agent and radiation. The first group received a subcurative regimen of Cilengitide 1 h before irradiation, while the second group received a curative regimen of Cilengitide 8 h before irradiation. Cilengitide was given as a single dose (4 mg/kg; intraperitoneal) after the pretreatment MRI study and before receiving a 20 Gy radiation dose. After irradiation, the post-treatment MRI study was performed at selected time points: 2, 4, 8 and 12 h (n = ≥5 per time point). Significant changes in vascular parameters were observed at early time points after combined treatments in both treatment groups (1 and 8 h). The temporal changes in vascular parameters in the first group (treated 1 h before exposure) resembled a previously reported pattern associated with radiation exposure alone. Conversely, in the second group (treated 8 h before exposure), all vascular parameters showed an initial response at 2–4 h postirradiation, followed by an apparent lack of response at later time points. The signature time point to define the “synergy” of Cilengitide and radiation was 4 h postirradiation. For example, 4 h after combined treatments using a 1 h separation (which followed the subcurative regimen), tumor blood flow was significantly decreased, nearly 50% below baseline (P = 0.007), whereas 4 h after combined treatments using an 8 h separation (which followed the curative regimen), tumor blood flow was only 10% less than baseline. Comparison between the first and second groups further revealed that most other vascular parameters were maximally different 4 h after combined treatments. In conclusion, the data are consistent with the assertion that the delivery of radiation at the vascular normalization time window of Cilengitide improves radiation treatment outcome. The different vascular responses after the different delivery times of combined treatments in light of the known tumor responses under similar conditions would indicate that timing has a crucial influence on treatment outcome and long-term survival. Tracking acute changes in tumor physiology after monotherapy or combined treatments appears to aid in identifying the beneficial timing for administration, and perhaps has predictive value. Therefore, judicial timing of treatments may result in optimal treatment response.

show abstract

Intratumor distribution and test–retest comparisons of physiological parameters quantified by dynamic contrast‐enhanced MRI in rat U251 glioma

Cited by 21 publications

References 28 publications

Effect of $$ T_{2}^{*} $$ correction on contrast kinetic model analysis using a reference tissue arterial input function at 7 T

Effect of $$ T_{2}^{*} $$ correction on contrast kinetic model analysis using a reference tissue arterial input function at 7 T

A continuous‐infusion dynamic MRI model at 3.0 Tesla for the serial quantitative evaluation of microvascular proliferation in an animal model of glioblastoma multiforme

Acute Temporal Changes of MRI-Tracked Tumor Vascular Parameters after Combined Anti-angiogenic and Radiation Treatments in a Rat Glioma Model: Identifying Signatures of Synergism

Contact Info

Product

Resources

About