Quantitative computed tomography assessment of transfusional iron overload

Wood, John C.; Mo, Ashley O.; Gera, Aakansha; Koh, Montre; Coates, Thomas D.; Gilsanz, Vicente

doi:10.1111/j.1365-2141.2011.08590.x

Cited by 19 publications

(20 citation statements)

References 32 publications

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“…Unfortunately, single energy techniques cannot accurately distinguish mild hepatic iron overload from normal fluctuations in liver attenuation. 18 Dualenergy scans compensate for background attenuation and newer dual-beam scanners potentially offer means to overcome this limitation, but these approaches have not been validated.…”

Section: Noninvasive Techniques For Lic Estimationmentioning

confidence: 98%

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Guidelines for quantifying iron overload

Wood

2014

Hematology

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106

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Both primary and secondary iron overload are increasingly prevalent in the United States because of immigration from the Far East, increasing transfusion therapy in sickle cell disease, and improved survivorship of hematologic malignancies. This chapter describes the use of historical data, serological measures, and MRI to estimate somatic iron burden. Before chelation therapy, transfusional volume is an accurate method for estimating liver iron burden, whereas transferrin saturation reflects the risk of extrahepatic iron deposition. In chronically transfused patients, trends in serum ferritin are helpful, inexpensive guides to relative changes in somatic iron stores. However, intersubject variability is quite high and ferritin values may change disparately from trends in total body iron load over periods of several years. Liver biopsy was once used to anchor trends in serum ferritin, but it is invasive and plagued by sampling variability. As a result, we recommend annual liver iron concentration measurements by MRI for all patients on chronic transfusion therapy. Furthermore, it is important to measure cardiac T2* by MRI every 6-24 months depending on the clinical risk of cardiac iron deposition. Recent validation data for pancreas and pituitary iron assessments are also presented, but further confirmatory data are suggested before these techniques can be recommended for routine clinical use.

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Section: Noninvasive Techniques For Lic Estimationmentioning

confidence: 98%

“…18 Using modern machines and scanning techniques, radiation exposure is Ͻ0.1 mSv, equivalent to a round-trip airline flight in North America. Unfortunately, single energy techniques cannot accurately distinguish mild hepatic iron overload from normal fluctuations in liver attenuation.…”

Section: Noninvasive Techniques For Lic Estimationmentioning

confidence: 99%

Guidelines for quantifying iron overload

Wood

2014

Hematology

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106

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“…The chief limitation of this approach is that changes in attenuation due to iron are small compared with normal attenuation fluctuations. Thus single energy qCT cannot accurately track LIC changes for LIC values less than 7 mg/g dry weight and is less accurate than MRI measurements for LIC values less than 15 or 20 mg/g[31, 32]. In contrast, qCT is quite robust for severe iron overload.…”

Section: Measurement Of Liver Iron Concentration (Lic)mentioning

confidence: 99%

Use of Magnetic Resonance Imaging to Monitor Iron Overload

Wood

2014

Hematology/Oncology Clinics of North America

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SYNOPSIS Treatment of iron overload requires robust estimates of total body iron burden and its response to iron chelation therapy. Compliance with chelation therapy varies considerably among patients and individual reporting is notoriously unreliable. Even with perfect compliance, intersubject variability in chelator effectiveness is extremely high, necessitating reliable iron estimates to guide dose titration. In addition, each chelator has a unique profile with respect to clearing iron stores from different organs. This chapter will present the tools available to clinicians monitoring their patients, focusing on non-invasive magnetic resonance imaging methods because they have become the de-facto standard of care.

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“…112 No significant data exist on measurement of cardiac iron by computed tomography. β-Blockers are generally used as premedication, which can affect the functional analysis, and radiation exposure is significant with repeated use.…”

Section: Cardiac Computed Tomography and Exercise Testingmentioning

confidence: 99%

Cardiovascular Function and Treatment in β-Thalassemia Major

Pennell¹,

Udelson²,

Arai³

et al. 2013

Circulation

324

172

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This aim of this statement is to report an expert consensus on the diagnosis and treatment of cardiac dysfunction in β-thalassemia major (TM). This consensus statement does not cover other hemoglobinopathies, including thalassemia intermedia and sickle cell anemia, in which a different spectrum of cardiovascular complications is typical. There are considerable uncertainties in this field, with a few randomized controlled trials relating to treatment of chronic myocardial siderosis but none relating to treatment of acute heart failure. The principles of diagnosis and treatment of cardiac iron loading in TM are directly relevant to other iron-overload conditions, including in particular Diamond-Blackfan anemia, sideroblastic anemia, and hereditary hemochromatosis. Heart failure is the most common cause of death in TM and primarily results from cardiac iron accumulation. The diagnosis of ventricular dysfunction in TM patients differs from that in nonanemic patients because of the cardiovascular adaptation to chronic anemia in non–cardiac-loaded TM patients, which includes resting tachycardia, low blood pressure, enlarged end-diastolic volume, high ejection fraction, and high cardiac output. Chronic anemia also leads to background symptomatology such as dyspnea, which can mask the clinical diagnosis of cardiac dysfunction. Central to early identification of cardiac iron overload in TM is the estimation of cardiac iron by cardiac T2* magnetic resonance. Cardiac T2* <10 ms is the most important predictor of development of heart failure. Serum ferritin and liver iron concentration are not adequate surrogates for cardiac iron measurement. Assessment of cardiac function by noninvasive techniques can also be valuable clinically, but serial measurements to establish trends are usually required because interpretation of single absolute values is complicated by the abnormal cardiovascular hemodynamics in TM and measurement imprecision. Acute decompensated heart failure is a medical emergency and requires urgent consultation with a center with expertise in its management. The first principle of management of acute heart failure is control of cardiac toxicity related to free iron by urgent commencement of a continuous, uninterrupted infusion of high-dose intravenous deferoxamine, augmented by oral deferiprone. Considerable care is required to not exacerbate cardiovascular problems from overuse of diuretics or inotropes because of the unusual loading conditions in TM. The current knowledge on the efficacy of removal of cardiac iron by the 3 commercially available iron chelators is summarized for cardiac iron overload without overt cardiac dysfunction. Evidence from well-conducted randomized controlled trials shows superior efficacy of deferiprone versus deferoxamine, the superiority of combined deferiprone with deferoxamine versus deferoxamine alone, and the equivalence of deferasirox versus deferoxamine.

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Quantitative computed tomography assessment of transfusional iron overload

Cited by 19 publications

References 32 publications

Guidelines for quantifying iron overload

Guidelines for quantifying iron overload

Use of Magnetic Resonance Imaging to Monitor Iron Overload

Cardiovascular Function and Treatment in β-Thalassemia Major

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