R2* imaging of transfusional iron burden at 3T and comparison with 1.5T

Storey, Pippa; Thompson, Alexis A.; Carqueville, Christine L.; Wood, John C.; Freitas, Roger A de; Rigsby, Cynthia K.

doi:10.1002/jmri.20816

Cited by 149 publications

(142 citation statements)

References 28 publications

(37 reference statements)

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“…The degree of hypointensity in the globus pallidus and substantia nigra is markedly more robust in 3T magnets. 9 In addition, the degree of hypointensity increases with age, consistent with an age-dependent iron deposition, 10,11 both in normal aging and in NBIA. To correctly identify excess iron clinically, one must thus have a working knowledge of both age-and field-dependent norms.…”

mentioning

confidence: 73%

Neuroimaging Features of Neurodegeneration with Brain Iron Accumulation

Kruer¹,

Boddaert²,

Schneider³

et al. 2011

AJNR Am J Neuroradiol

184

160

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SUMMARY: NBIA characterizes a class of neurodegenerative diseases that feature a prominent extrapyramidal movement disorder, intellectual deterioration, and a characteristic deposition of iron in the basal ganglia. The diagnosis of NBIA is made on the basis of the combination of representative clinical features along with MR imaging evidence of iron accumulation. In many cases, confirmatory molecular genetic testing is now available as well. A number of new subtypes of NBIA have recently been described, with distinct neuroradiologic and clinical features. This article outlines the known subtypes of NBIA, delineates their clinical and radiographic features, and suggests an algorithm for evaluation.ABBREVIATIONS: ACP ϭ aceruloplasminemia; CNS ϭ central nervous system; FAHN ϭ fatty acid hydroxylase-associated neurodegeneration; INAD ϭ infantile neuroaxonal dystrophy; KRS ϭ KuforRakeb syndrome; NAD ϭ neuroaxonal dystrophy; NBIA ϭ neurodegeneration with brain iron accumulation; NFT ϭ neuroferritinopathy; PKAN ϭ pantothenate kinase-associated neurodegeneration; PLAN ϭ phospholipase-associated neurodegeneration; SENDA ϭ static encephalopathy of childhood with neurodegeneration in adulthood; WSS ϭ Woodhouse-Sakati syndrome B efore the widespread availability of MR imaging, a diagnosis of NBIA could be made only at the time of autopsy. In contrast, current diagnosis is facilitated by evaluation by using both T1-and T2-weighted sequences. As a paramagnetic substance, Fe 3ϩ catalyzes the nuclear spin relaxation of neighboring water protons. With standard clinical parameters, areas rich in iron appear hypointense on T2-weighted sequences, and isointense on T1 sequences. T2*-weighted acquisitions (gradient-echo sequences) may accentuate this degree of hypointensity ("blooming") and may be helpful in identifying NBIA disorders as may susceptibility-weighted images.1 In biologic iron-oxides, Fe 2ϩ typically has fewer unpaired electrons than Fe 3ϩ and is less effective in quenching T2-weighted signal intensity.2 Calcium may also appear isointense on T1 and hypointense on T2-weighted sequences, mimicking the appearance of iron. The 2 minerals are readily distinguished by CT, however, because Ca 2ϩ characteristically appears hyperintense to the surrounding brain parenchyma, while iron is isointense. In addition, iron typically appears markedly hypointense on both standard clinical diffusionweighted and apparent diffusion coefficient sequences. Other metals that may be deposited in neurodegenerative disorders, such as manganese and copper, have a distinct appearance on T1-and T2-weighted sequences, enabling a heuristic approach to diagnosis based on MR imaging parameters. The characteristics of these metals are summarized in Table 1. Despite the utility of MR imaging in this setting, it does not preclude the need for elemental analysis of neuropathologic specimens; rather, it enables putative diagnosis to be made during life.The radiographic appearance of the lesions themselves is of prime importance. Iron deposition occurs in mul...

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mentioning

confidence: 73%

Neuroimaging Features of Neurodegeneration with Brain Iron Accumulation

Kruer¹,

Boddaert²,

Schneider³

et al. 2011

AJNR Am J Neuroradiol

184

160

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“…With a single breath-hold approach, we were able to cover a larger LIC range compared to other studies at 3 T [9]. Storey et al had to adapt their MRI acquisition protocol if low liver signals were observed, i. e. for an LIC larger than 25 mg/g [10]. Theoretical considerations are independent of field strength.…”

Section: Signal Noise (Snr)mentioning

confidence: 98%

“…Therefore, the development of reliable standardized MRI-based methods to determine LIC has been of clinical and scientific interest for a long time (e. g. [1 -6]). As there are few recent studies using 3 T in animals [7,8] and humans [9,10], established broadly accessible methods work at 1.5 T. A commercially available method based on T 2 analysis of spin-echo (SE) data [3] is FDA approved and meets the quality requirements for clinical use. It requires scanner calibration and long measurement times, and data has to be transferred for data analysis.…”

mentioning

confidence: 99%

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MRI-Based Liver Iron Content Determination at 3T in Regularly Transfused Patients by Signal Intensity Ratio Using an Alternative Analysis Approach Based on R2* Theory

Wunderlich

Cario

Bommer

et al. 2016

Fortschr Röntgenstr

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▼Objectives: To evaluate the feasibility of addressing liver iron content (LIC) in regularly transfused patients by MR imaging at 3 T based on the signal intensity ratio (SIR). An innovative data analysis approach was developed for this purpose. Methods: 47 consecutive examinations of regularly transfused patients were included. In all cases, we expected high LIC levels. Patients were scanned with MRI at 3 T with multi-echo gradient echo sequences (GRE) at four different flip angles between 20°and 90°with echo times (TE) ranging from 0.9 to 9.8 ms. Spin-echo protocols were acquired to determine the LIC with a reference MRI method working at 1.5 T. 3 T GRE data were analyzed using the liver-to-muscle SIR. Since the method known for 1.5 T was not expected to be applicable for analyzing 3 T data, theoretic dependence of the SIR on the LIC was derived from the equation describing R 2 * signal decay. Obtained SIR values were correlated to reference LIC to get a relation for calculating LIC from SIR quantities. LIC values and their uncertainties were determined from GRE data and correlated to LIC reference values. For two LIC thresholds, the diagnostic accuracy was determined. Results: LIC was reliably determined from SIR in our patient cohort even for large LIC values. Median of LIC uncertainties was 10 %, and the diagnostic accuracy was 0.92 and 0.91, respectively. Conclusion: Determination of even high LIC, resulting in small SIR values, is feasible at 3 T using appropriate SIR analysis.

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“…Its long half-life of [11][12][13][14][15][16][17][18][19] hours maintains plasma levels within the therapeutic range over a 24-hour period, allowing for a convenient once-daily oral administration and offering a viable option over deferoxamine and its associated problems with compliance. 27,28 The pharmacokinetics of deferasirox in pediatric patients is similar to that in older patients: once-daily dosing is able to control freely circulating plasma iron during a 24-hour period, preventing potential damage by NTBI.…”

Section: Deferasiroxmentioning

confidence: 99%

Iron Overload and Iron Chelation Therapy in Pediatric Patients

Vichinsky¹

2009

Oncology &Amp; Hematology Review (US)

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Iron overload is an unfortunate clinical consequence of repeated blood transfusions that can cause significant organ damage, morbidity, and mortality in the absence of proper treatment. Pediatric patients with transfusion-dependent pathologies face the additional risk of growth failure and poor sexual development owing to iron build-up in the anterior pituitary gland. Iron chelation therapy is necessary for the removal of excess iron, but treatment efficacy and success are highly dependent on patient compliance. Deferoxamine is a well-established but inconvenient therapy requiring parenteral administration over extended periods of time. Patient compliance can be improved with use of the oral iron chelators deferasirox and deferiprone. Long-term data have shown deferasirox to have a good safety and efficacy profile in pediatric patients. KeywordsIron overload, hemoglobinopathies, pediatric, iron chelator, compliance Disclosure: Elliott Vichinsky, MD, is an investigator for and has received honoraria from Novartis.

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R2* imaging of transfusional iron burden at 3T and comparison with 1.5T

Cited by 149 publications

References 28 publications

Neuroimaging Features of Neurodegeneration with Brain Iron Accumulation

Neuroimaging Features of Neurodegeneration with Brain Iron Accumulation

MRI-Based Liver Iron Content Determination at 3T in Regularly Transfused Patients by Signal Intensity Ratio Using an Alternative Analysis Approach Based on R2* Theory

Iron Overload and Iron Chelation Therapy in Pediatric Patients

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