Quantification of dynamic contrast-enhanced MR imaging of the knee in children with juvenile rheumatoid arthritis based on pharmacokinetic modeling

Workie, D; Dardzinski, Bernard J.; Graham, T. Brent; Laor, Tal; Bommer, Wendy A.; O’Brien, Kendall

doi:10.1016/j.mri.2004.09.006

Cited by 58 publications

(44 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Workie et al (42,43) validated the linear relationship for 3D-GRE images under condition of low Gd-DTPA concentrations (11). Our fitted transfer constant is also equal to apparent K trans as defined in their work.…”

Section: Discussionsupporting

confidence: 68%

Quantitative correlation between 1H MRS and dynamic contrast-enhanced MRI of human breast cancer

Baek

Chen

et al. 2008

Magnetic Resonance Imaging

View full text Add to dashboard Cite

Proton MR spectroscopy ( 1 H MRS) and dynamic contrast-enhanced (DCE) MR imaging provide functional information, including vascular volume, vascular permeability, and choline (Cho) metabolism. In this study, we applied these two imaging modalities to quantitatively characterize 36 malignant breast lesions in 32 patients and analyzed the correlation between them. The Cho concentration was quantified by single-voxel 1 H MRS using water as an internal reference. The measured Cho levels ranged from 0.32 to 10.47 mmol/kg, consistent with previously reported values. In 25 mass type lesions, the Cho concentration was significantly correlated with tumor size (r = 0.69, p < 0.0002). In addition, the Cho level was found to be significantly higher in lesions presenting as mass type lesions compared to non-mass type diffuse enhancements (p = 0.035). The enhancement kinetics from tissues covered within each MRS voxel were measured and analyzed with a 2-compartmental model to obtain pharmacokinetic parameters K trans and k ep . A significant correlation was found between the Cho level and pharmacokinetic parameter k ep (r = 0.62, p < 0.0001), indicating that tissues with a high Cho level have higher wash-out rates in DCE MR imaging. The results suggest a correlation between choline metabolism and angiogenesis activity, which might be explained by the association of Cho with cell replication and angiogenesis required to support tumor growth.

show abstract

Section: Discussionsupporting

confidence: 68%

Quantitative correlation between 1H MRS and dynamic contrast-enhanced MRI of human breast cancer

Baek

Chen

et al. 2008

Magnetic Resonance Imaging

View full text Add to dashboard Cite

show abstract

“…In the low concentration limit, we can expand equation (4) to linear order in C and take the lim T R , T E →0 to obtain the commonly used linear approximation (Tofts 1997, Workie et al 2004:…”

Section: Relative Signal Enhancement With Contrast Concentrationmentioning

confidence: 99%

Uncertainty and bias in contrast concentration measurements using spoiled gradient echo pulse sequences

Schabel¹,

Parker²

2008

Phys. Med. Biol.

200

266

View full text Add to dashboard Cite

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a widely used technique for assessing tissue physiology. Spoiled gradient echo (SPGR) pulse sequences are one of the most common methods for acquisition of DCE-MRI data, providing high temporal and spatial resolution with strong T 1 -weighting. Conversion of SPGR signal to concentration is briefly reviewed, and a new closed-form expression for concentration measurement uncertainty for finite signal-to-noise ratio (SNR) and baseline scan time is derived. This result is applicable to arbitrary concentrationdependent relaxation rate and is valid over the same domain as the theoretical SPGR signal equation. Expressions for the lower and upper bounds on measurable concentration are also derived. The existence of a concentration-and tissue-dependent optimal flip angle that minimizes concentration uncertainty is demonstrated and it is shown that, for clinically relevant pulse sequence parameters, this optimal flip angle is significantly larger than the corresponding Ernst angle. Analysis of three pulse sequences from the DCE-MRI literature shows that optimization of flip angle using the methods discussed here leads to potential improvements of 10-1166% in effective SNR over the 0.5-5.0 mM concentration range with minimal or no loss of measurement accuracy down to 0.1 mM. In vivo data from three study patients provide further support for our theoretical expression for concentration measurement uncertainty, with predicted and experimental estimates agreeing to within ±30%. Equations for concentration bias resulting from biases in flip angle and from pre-contrast relaxation time and contrast relaxivity (both longitudinal and transverse) are also derived in closed-form. The resulting equations show the potential for significant contributions to bias in concentration measurement arising from even relatively small mis-specification of flip angle and/or pre-contrast longitudinal relaxation time, particularly at high contrast concentrations.

show abstract

“…, and inflammation (3). Quantitative parameters directly related to underlying physiological properties, such as vessel permeability, perfusion, and blood volume, may be obtained by applying a pharmacokinetic model to the DCE-MRI data (4).…”

mentioning

confidence: 99%

Investigation and optimization of parameter accuracy in dynamic contrast‐enhanced MRI

Cheng

2008

Magnetic Resonance Imaging

View full text Add to dashboard Cite

Purpose: To present a modified pharmacokinetic model for improved parameter accuracy and to investigate the influence of an inaccurate arterial input function (AIF) on dynamic contrast-enhanced (DCE)-MRI parameter estimates of the transfer constant (K trans ), blood volume (v p ), and interstitial volume (v e ). Materials and Methods:Tissue uptake curves were simulated over a large range of physiological values and analyzed for different AIF measurement errors and temporal resolutions. The AIF measurement was assumed to be inaccurate in the bolus amplitude (rapid sampling) or susceptible to unknown temporal offsets (slow sampling with biexponential decay fit). Results:The modified model adequately reduces errors in parameter estimates arising from transit time effects. An error in the AIF bolus amplitude results in an inversely proportional error in K trans and v p ; v e remains robust. More consistent error in K trans (Ϸ20% underestimation) was obtained using a biexponential AIF, at the expense of severely underestimating v p . Conclusion:While an accurate, high temporal resolution AIF is essential for estimating v p , a biexponential AIF acquired at low temporal resolution (Ͻ20 seconds) provides robust estimates of v e and results in a K trans underestimation comparable to that from a 25% error in the initial AIF bolus amplitude. DYNAMIC CONTRAST-ENHANCED (DCE)-MRI for characterizing tissue uptake of a contrast agent is an established method for assessing microcirculation physiology. It is relevant in studying a wide range of diseases and conditions, including cancer (1), ischemia (2), and inflammation (3). Quantitative parameters directly related to underlying physiological properties, such as vessel permeability, perfusion, and blood volume, may be obtained by applying a pharmacokinetic model to the DCE-MRI data (4). This physiology-based information is beneficial in a number of ways, from improving cancer diagnostic sensitivity and specificity to elucidating microvascular changes that accompany novel anticancer therapies. However, the degree to which measured parameters represent true physiology is influenced by a number of factors, and accurate DCE-MRI quantification remains challenging (5).A problematic but necessary requirement for quantitative DCE-MRI is measurement of the arterial input function (AIF), or contrast agent concentration time course in the blood pool. The simplest approach is to use a standard AIF (6), but this may differ from the individual's input function, and large errors in pharmacokinetic parameter estimates have been reported (7). The ideal approach is to obtain individual measurements. This, however, is beset by a number of challenges. One challenge is achieving a high temporal resolution (1 second) to capture rapid changes during the initial bolus passage, which is believed to be essential for reliable DCE-MRI quantification (8). Despite the availability of faster scanners and parallel imaging, a lower temporal resolution is often used due to competing demands for high spatial res...

show abstract

Quantification of dynamic contrast-enhanced MR imaging of the knee in children with juvenile rheumatoid arthritis based on pharmacokinetic modeling

Cited by 58 publications

References 39 publications

Quantitative correlation between 1H MRS and dynamic contrast-enhanced MRI of human breast cancer

Quantitative correlation between 1H MRS and dynamic contrast-enhanced MRI of human breast cancer

Uncertainty and bias in contrast concentration measurements using spoiled gradient echo pulse sequences

Investigation and optimization of parameter accuracy in dynamic contrast‐enhanced MRI

Contact Info

Product

Resources

About