The overall goal of this research is to help develop a new magnetic resonance (MR) method, Quantitative Susceptibility Mapping (QSM), to improve the measurement of liver iron concentrations without the need for a liver biopsy. Measurement of liver iron is important to diagnose and treat patients who have too much iron in their bodies (iron overload). Liver iron measurements by current MRI methods (R2 and R2\*) can be inaccurate because of the effects of fat, fibrosis and other abnormalities. QSM should not be affected by these factors and should be free of these errors. In this study, MRI measurements (QSM, R2 and R2\*) of iron in patients before liver transplant will be compared with chemical analysis of iron in liver explants (livers removed from patients undergoing liver transplant). The liver explants would otherwise be discarded. Investigators expect that this study will show that the new MRI method, QSM, is superior to the current MRI methods, R2 and R2\*.
The overall objective of this research is to improve the safety of iron-chelating therapy (ICT) in patients with transfusional iron overload by developing an accurate non-invasive measurement of the liver iron concentration (LIC), the best measure of the body iron burden in all forms of systemic iron overload. The scientific premise is that quantitative susceptibility mapping (QSM) provides a quantitative biophysical connection to LIC. Safe ICT requires careful adjustment of the iron chelator dose to the body iron burden to optimize iron excretion while avoiding chelator toxicity, including gastrointestinal disorders, audiovisual impairment, neutropenia, arthropathy, growth retardation, and hepatic and renal failure. QSM enables accurate measurement of LIC by overcoming the inherent cellular interference in current R2 (=1/T2) and R2\* (=R2+R2') estimates that lack a well-defined biophysical connection to the LIC. A fundamental biophysical limitation of the R2 and R2\* approaches is that intravoxel contents other than iron, including fibrosis, steatosis and necroinflammation, also alter relaxation. In the liver, paramagnetic iron stored in ferritin and hemosiderin is the dominant susceptibility source for QSM. Consequently, magnetic susceptibility measured by QSM has a simple linear relationship with the concentration of iron in the liver and is little affected by fibrosis, steatosis and necroinflammation. The investigator's research plan has 3 specific aims: Aim 1. Develop hQSM for accurate measurement of LIC without interfering errors. Investigators will optimize data acquisition and processing for free-breathing navigator acquisition with robust fat-water separation. Aim 2. Validate hQSM using histology and chemical measurement of LIC in liver explants. Investigators will assess the accuracies of LICs measured by hQSM and R2\* in patients before liver transplant with histologic examination using the reference standard of chemical measurement of LIC in liver explants. Aim 3. Evaluate hQSM in patients with transfusional iron overload under ICT. In patients regularly transfused for thalassemia major, investigators will conduct a double-blind clinical study comparing the accuracy of hQSM and R2\* in measuring annual changes in LIC, using regression against the year-long amount of iron administered in red blood cell transfusions and the year-long cumulative dose of iron chelator.
Study Type
OBSERVATIONAL
Enrollment
42
Investigators will validate hepatic QSM (hQSM) using histological examination and chemical measurement of liver iron concentration (LIC). Patients will undergo clinical MRI in Aim 1. In patients with increased LIC their liver explants will undergo MRI, pathological examination, and chemical determination of the LIC.
Investigators will be able to validate hQSM in measuring liver iron concentration (LIC) by comparing it to this traditional MRI technique
Weill Cornell Medical College
New York, New York, United States
RECRUITINGColumbia University Medical Center
New York, New York, United States
RECRUITINGDemonstration of efficacy of quantitative susceptibility mapping (QSM) MRI in quantifying liver iron concentration (LIC)
Investigators will assess the accuracy of liver iron concentrations measured by QSM in patients before liver transplant with histologic examination using the gold standard chemical measurement of LIC in liver explants.
Time frame: Five years
Fibrosis as determined by in vivo R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Fibrosis as determined by in vitro R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Fibrosis as determined by in vivo hQSM, an MRI post-processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
Fibrosis as determined by in vitro hQSM, an MRI post processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
Steatosis as determined by in vivo R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Steatosis as determined by in vitro R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Steatosis as determined by in vivo hQSM, an MRI post-processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
Steatosis as determined by in vitro hQSM, an MRI post-processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
Necroinflammation as determined by in vivo R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Necroinflammation as determined by in vitro R2*, an MRI method that provides quantitative information on iron levels
R2\* is an imaging method used in MRI. R2\* = (1/T2\*) where R2\* is a relaxation rate measured in units of Hz (\[1/sec\]). R2\* is commonly used to look at iron levels by measuring the relaxation times of hydrogen nuclei affected by iron. The presence of the iron results in the shortening of proton relaxation times (T2\*), thus increasing R2\*.
Time frame: Five years
Necroinflammation as determined by in vivo hQSM, an MRI post-processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
Necroinflammation as determined by in vitro hQSM, an MRI post-processing technique that provides quantitative information on iron levels
Quantitative susceptibility mapping (QSM) is widely used by the imaging research community in applications to detect iron. Tissue can become magnetized in response to a magnetic field, and the extent of magnetization is known as susceptibility, which arises from unpaired electrons in iron or external sources such as contrast agents. QSM permits visualization of the sizes and shapes of iron sources, delivers precise estimates of iron concentrations (units: parts per billion \[ppb\] or parts per million \[ppm\]).
Time frame: Five years
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