R2 relaxometry with MRI for the quantification of tissue iron overload in β‐thalassemic patients

Alexopoulou, Efthymia; Stripeli, Fotini; Baras, Panagiotis; Seimenis, Ioannis; Kattamis, Antonis; Ladis, Vassilios; Efstathopoulos, Efstathios; Brountzos, Elias; Kelekis, Alexis; Kelekis, Nikolaos

doi:10.1002/jmri.20489

Cited by 79 publications

(87 citation statements)

References 34 publications

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“…These contributions are expected to operate at a macroscopic scale (up to centimetres) (14). The presence of these artefacts was found to be minimal in the mid-ventricular septum, hence the measurement of cardiac T 2 Ã has been limited to this location in clinical practice (5,6,22,23). When the entire myocardium was analyzed in healthy subjects and patients, a noticeable spatial variation in T 2 Ã assessment across the myocardium was documented (8,12,13).…”

Section: Discussionmentioning

confidence: 98%

Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts

et al. 2007

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A segmental, multislice, multi-echo T 2 Ã MRI approach could be useful in heart iron-overloaded patients to account for heterogeneous iron distribution, demonstrated by histological studies. However, segmental T 2 Ã assessment in heart can be affected by the presence of geometrical and susceptibility artefacts, which can act on different segments in different ways. The aim of this study was to assess T 2 Ã value distribution in the left ventricle and to develop a correction procedure to compensate for artefactual variations in segmental analysis. MRI was performed in four groups of 22 subjects each: healthy subjects (I), controls (II) (thalassemia intermedia patients without iron overload), thalassemia major patients with mild (III) and heavy (IV) iron overload. Three short-axis views (basal, median, and apical) of the left ventricle were obtained and analyzed using custom-written, previously validated software. The myocardium was automatically segmented into a 16-segment standardized heart model, and the mean T 2 Ã value for each segment was calculated. Punctual distribution of T 2 Ã over the myocardium was assessed, and T 2 Ã inhomogeneity maps for the three slices were obtained. In group I, no significant variation in the mean T 2 Ã among slices was found. T 2 Ã showed a characteristic circumferential variation in all three slices. The effect of susceptibility differences induced by cardiac veins was evident, together with low-scale variations induced by geometrical artefacts. Using the mean segmental deviations as correction factors, an artefact correction map was developed and used to normalize segmental data. The correction procedure was validated on group II. Group IV showed no significant presence of segmental artefacts, confirming the hypothesis that susceptibility artefacts are additive in nature and become negligible for high levels of iron overload. Group III showed a greater variability with respect to normal subjects. The correction map failed to compensate for these variations if both additive and percentage-based corrections were applied. This may reinforce the hypothesis that true inhomogeneity in iron deposition exists.

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Section: Discussionmentioning

confidence: 98%

Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts

et al. 2007

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“…Bone marrow iron stores were assessed semiquantitatively on Prussian-blue-stained marrow smears according to the following scale: grade 0= absent; 1=decreased; 2=normal; 3=increased; 4=markedly increased; 5=massively increased. LIC was determined quantitatively by T2*-weighted MRI as described previously [24][25][26]. An LIC >35-µmol/g liver tissue was considered as iron overload.…”

Section: Methodsmentioning

confidence: 99%

Deferasirox in MDS patients with transfusion-caused iron overload—a phase-II study

et al. 2008

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International audienceBlood transfusions represent a main component of supportive care in myelodysplastic syndromes (MDS). To avoid organ damage caused by transfusion-dependent iron overload, an adequate iron chelation therapy is required. Recently, a new oral iron chelator deferasirox (ICL670, Exjade®) has become available. A study was conducted to demonstrate the efficacy and tolerability of deferasirox in transfusion-dependent iron-overloaded patients with MDS. The efficacy of deferasirox was monitored by changes in serum ferritin, bone marrow iron, and liver iron concentration (LIC), as determined by T2*-weighted magnetic resonance imaging. Twelve patients with MDS of different subtypes (median age 76 years, range 53–91) were enrolled. Deferasirox administered in a once-daily dose of 20–30 mg/kg for 12 months was effective in reducing median ferritin concentration from 1,515 µg/L (range 665–6,900) to 413 µg/L (range 105–3,052). Within the first 4 weeks of treatment before the continuous decline of ferritin levels, the values markedly rose in eight of 12 patients. The median LIC declined from 315 to 230 µmol/g ( = 0.02) at the end of study, accompanied by a reduction of bone marrow siderosis. The most common adverse events were mild and transient gastrointestinal disturbances, skin rash, nonprogressive transient increases in serum creatinine and urine β2-microglobulin, and a temporary reduction of the creatinine clearance. The renal parameters normalized after end of treatment. No hematologic toxicities were observed. Deferasirox proved to be effective in transfusion-dependent iron overload in MDS by mobilizing iron deposits in liver and at least stabilizing iron stores in bone marrow

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“…Signal intensity ratio methods measure the signal intensity of the liver and another tissue or noise and give proportion of these to quantify the liver iron (10,11), whereas relaxometry methods measure signal intensity of the liver across multiple echo times and calculate T2 or T2* values depending on the performed sequence (12). T2 or T2* values are inversely related with iron concentration.…”

mentioning

confidence: 99%

Different forms of iron accumulation in the liver on MRI

İdilman

Akata²,

Özmen³

et al. 2015

Diagn Interv Radiol

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R2 relaxometry with MRI for the quantification of tissue iron overload in β‐thalassemic patients

Cited by 79 publications

References 34 publications

Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts

Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts

Deferasirox in MDS patients with transfusion-caused iron overload—a phase-II study

Different forms of iron accumulation in the liver on MRI

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R2 relaxometry with MRI for the quantification of tissue iron overload in β‐thalassemic patients

Cited by 79 publications

References 34 publications

Standardized T2* map of normal human heart in vivo to correct T2* segmental artefacts

Standardized T2* map of normal human heart in vivo to correct T2* segmental artefacts

Deferasirox in MDS patients with transfusion-caused iron overload—a phase-II study

Different forms of iron accumulation in the liver on MRI

Contact Info

Product

Resources

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Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts

Standardized T₂* map of normal human heart in vivo to correct T₂* segmental artefacts