Quantification of Liver Iron Overload by T2 Quantitative Magnetic Resonance Imaging in Thalassemia

Papakonstantinou, Olympia; Kostaridou, Stavroula; Maris, Thomas G.; Γουλιάμος, Αθανάσιος; Premetis, Evangelos; Kouloulias, Vasileios; Nakopoulou, L; Kattamis, Christos

doi:10.1097/00043426-199903000-00011

Cited by 47 publications

(45 citation statements)

References 33 publications

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“…Signal intensity, S, was generated using the signal equation for a gradient-echo sequence. A longitudinal relaxation time of T 1 ϭ 586 ms for liver (24) was assumed, and MR parameters were chosen to correspond to two T* 2 multi-echo gradientecho sequences adopted in our institution for clinical assessment of liver iron: breath-held (TE ϭ [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Gaussian-distributed complex noise, with standard deviation noise , was added to the generated signal. Different signal-to-noise ratios (SNR ϭ M 0 / noise , where M 0 is the fully relaxed magnetization) in the range 20 to 300 were evaluated.…”

Section: Simulationsmentioning

confidence: 99%

“…Thus, although the two model fits are theoretically identical under noiseless conditions, their divergence is apparent as SNR is reduced. Figure 2 compares the performance of all three curvefitting models using two different acquisition schemes (TE ϭ [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Fig. 2a) and echo spacing (min TE ϭ 1 ms), all models provide accurate R* 2 estimates.…”

Section: Patient Studymentioning

confidence: 99%

“…In recent years, magnetic resonance imaging (MRI) has emerged as the most widely used noninvasive technique to quantify liver iron content, and correlation with biopsy results has been demonstrated (9 -11). To date, there have been many applications of MRI to study liver iron (12)(13)(14)(15)(16)(17), and several methods exist for acquiring and analyzing the MRI data. However, our understanding of how to optimize these procedures for accurate iron measurement needs to be improved.…”

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confidence: 99%

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Accurate liver T measurement of iron overload: A simulations investigation and in vivo study

Beaumont

Odame

Babyn

et al. 2009

Magnetic Resonance Imaging

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Purpose:To investigate the accuracy of T* 2 liver iron quantification using different curve-fitting models under varying acquisition conditions, and to compare in iron-overloaded patients the reliability of rapid T* 2 measurements against approved and slower T 2 protocols. Materials and Methods:Simulations were conducted to assess the influence of various factors on the accuracy of T* 2 measurement: curve-fitting model, signal-to-noise ratio (SNR), and echo time (TE) spacing. Fifty-four iron-overloaded pediatric patients were assessed using a standard T 2 and two variations of T* 2 acquisitions. In both simulations and in vivo data, three analysis models were evaluated: monoexponential, constant offset, and truncated. Results:Simulations show the truncated model provides the best accuracy but is susceptible to underestimating high iron species under low SNR or high minimum TE. In contrast, the offset model tends to overestimate but maintains the most reliable measurements across the relevant range of iron levels. Furthermore, a much lower SNR can be tolerated if the acquisition uses a low minimum TE. In vivo results confirm theoretical findings and show that T* 2 measurements can be as reliable as those from approved and slower T 2 protocols. Conclusion:Guidelines are provided on choosing an appropriate model under specific noise conditions and acquisition schemes to ensure accurate and rapid T* 2 liver iron quantification.

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Section: Simulationsmentioning

confidence: 99%

Section: Patient Studymentioning

confidence: 99%

mentioning

confidence: 99%

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Accurate liver T measurement of iron overload: A simulations investigation and in vivo study

Beaumont

Odame

Babyn

et al. 2009

Magnetic Resonance Imaging

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“…It has been previously shown that the relaxation rate R2 was a useful parameter to quantify hepatic iron concentration both in human (1-7) and animal studies (8)(9)(10)(11). However, given the fact that only noninvasive methods can be used, there is no validated sequence for the determination of splenic iron concentration which is a key point for the diagnosis.…”

Section: Discussionmentioning

confidence: 99%

“…Several groups have reported noninvasive quantification of hepatic iron overload using MRI methods (5). Most studies were done on humans (6)(7)(8)(9)(10)(11), only a few having been performed on rodents (12)(13)(14)(15).…”

mentioning

confidence: 99%

MRI quantification of splenic iron concentration in mouse

Hitti

Éliat

Abgueguen

et al. 2010

Magnetic Resonance Imaging

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Purpose: To quantify hepatic and splenic iron load, which is a critical issue for iron overload disease diagnosis. MRI is useful to noninvasively determine liver iron concentration, but not proven to be adequate for robust evaluation of splenic iron load. We evaluated the usefulness of MRI-derived parameters to determine splenic iron concentration in mice. Materials and Methods:A mouse model of experimental iron load was used. Multi-echo spin-echo images of liver and spleen were acquired at 4.7 Tesla. The parameters were tested at all echoes with and without an external reference. Splenic and hepatic iron concentrations were determined using biochemical assay as the gold standard.Results: Our results show that (i) use of an internal or external reference is essential; (ii) optimal echo times were TE ¼ 19.5 ms and TE ¼ 32.5 ms for the liver and spleen, respectively; (iii) in the liver, the relationship between biochemical and MRI iron concentration determinations is logarithmic; (iv) in the spleen, the best relationship is an inverse function. Conclusion:A single spin-echo sequence allows robust estimation of hepatic and splenic iron content. Parameters classically used for hepatic iron concentration cannot be applied to splenic iron determination, which requires both the specific sequence and the adapted fitting function.

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Irinotecan and chronomodulated infusion of 5-fluorouracil and folinic acid in the treatment of patients with advanced colorectal carcinoma

Garufi

Dogliotti

Dattino

et al. 2001

Cancer

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Quantification of Liver Iron Overload by T2 Quantitative Magnetic Resonance Imaging in Thalassemia

Cited by 47 publications

References 33 publications

Accurate liver T measurement of iron overload: A simulations investigation and in vivo study

Accurate liver T measurement of iron overload: A simulations investigation and in vivo study

MRI quantification of splenic iron concentration in mouse

Irinotecan and chronomodulated infusion of 5-fluorouracil and folinic acid in the treatment of patients with advanced colorectal carcinoma

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