Hemochromatosis MRI
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American Roentgen Ray Society Images of Hemochromatosis MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Shyam Patel [2]; Associate Editor(s)-in-Chief: Sunny Kumar MD [3]
Overview
MRI is not only the most sensitive imaging modality for the diagnosis of haemochromatosis but is also able to estimate iron concentration within the liver, thus forestalling the need for repeated biopsies.
MRI
MRI is not only the most sensitive imaging modality for the diagnosis of haemochromatosis but is also able to estimate iron concentration within the liver and cardiac muscle, thus forestalling the need for repeated biopsies.[1]
MR liver (or heart) iron quantification is a non-invasive means of measuring liver iron concentration, a key indicator in the management of patients with haemochromatosis (primary or secondary)
Following are the methods of measurements:
- Signal intensity ratio (SIR)-The ratio between the signal intensity of the liver and the signal intensity of paraspinal muscle that does not accumulate iron can be used to determine liver iron concentration.
- T2 relaxometry vs. SIR methods-Estimating liver iron content is easier to perform with SIR compared with T2 relaxometry. SIR methods are less accurate at an iron concentration of >350 micromol Fe/g.
- T2 relaxometry-ron within liver has paramagnetic properties and results in a decrease in T2 relaxation times. The accelerated relaxation is proportional to iron content. Decay models are attributed to the average signal intensity at different echo times.
- MRI carries no risk for radiation, unlike CT scan.
- MRI is significantly more expensive than CT scan.
References
- ↑ St Pierre TG, Clark PR, Chua-anusorn W, Fleming AJ, Jeffrey GP, Olynyk JK; et al. (2005). "Noninvasive measurement and imaging of liver iron concentrations using proton magnetic resonance". Blood. 105 (2): 855–61. doi:10.1182/blood-2004-01-0177. PMID 15256427.