21 Oct ACG 2022 Annual Scientific Meeting, Charlotte, North Carolina

ASX:RHT

Why use FerriScan® to analyse Liver Iron Concentration (LIC)?

A comparison with other LIC evaluation methods

Advantages of FerriScan® over Serum Ferritin (SF)

  1. Diverse factors such as infection, inflammation, fever, cancer, metabolic disease or liver damage may result in significant elevation of SF concentrations in the absence of iron overload. Increased SF may indicate iron overload, but is not a quantitative measure of iron burden.
  2. For patients with thalassaemia major, SF has poor accuracy for measuring body iron loading.
  3. For patients with thalassaemia intermedia, SF are considerably lower than with thalassaemia major patients that have comparable LIC levels as determined by biopsy, which suggests that SF significantly underestimates iron loading in patients with thalassaemia intermedia.
  4. In patients with sickle cell disease (SCD), SF is an imprecise and potentially misleading parameter on which to manage patients with. In paediatric patients with SCD, SF has significant limitations in the assessment of iron burden.
  5. In patients with hereditary haemochromatosis, the relationship between SF and total body iron stores is very weak.

Advantages of FerriScan® over Liver Biopsy

  1. FerriScan® is painless and with no risk of bleeding nor infection.
  2. FerriScan® provides information about the distribution of iron in the liver.
  3. The size of the biopsy specimen only represents 1/50,000th of the total mass of the liver, therefore the sampling error is potentially large depending on the biopsy location. FerriScan evaluates iron in a volume of liver that is thousands of times greater than liver biopsy, and therefore has a much smaller sampling error.

Advantages of FerriScan® over Liver T2* (MRI)

  1. There are many liver T2* techniques and they are not standardised. Non-standardisation means that it is very difficult to compare results.
  2. Liver T2* techniques are not regulatory cleared for producing LIC.
  3. Some Liver T2* techniques are highly unreliable at higher LIC.
  4. Liver T2* techniques do not report across the full range of iron loading seen in clinical practice.
  5. Liver T2* techniques can be influenced by the presence of liver fat and fibrosis.
  6. Liver T2* techniques generate data that are dependent on both data acquisition protocol and method of data analysis and hence are not fully standardised to enable reliable LIC measurements using calibration curves from other centres.
  7. Liver T2* to LIC conversion depends on a number of factors such as scanning profile, method of analysis, which calibration curve is used. Please see the table below for variances in several liver T2* techniques.
Reference LIC for T2* = 2.5 ms in mg Fe/g dry tissue
1 26.4
2 16.9
7 15.7
3 15.4
5 12.7
4 12.6
6 11.6
8 10.8
10 10.7
9 10.7
11 10.4
13 9.9
12 9.8
14 5.4
15 2.7