Background: There is a need for improved worldwide access to tissue iron quantification using T2* cardiovascular magnetic resonance (CMR). One route to facilitate this would be simple in-line T2* analysis widely available on MR scanners. We therefore compared our clinically validated and established T2* method at Royal Brompton Hospital (RBH T2*) against a novel work-in-progress (WIP) sequence with in-line T2* measurement from Siemens (WIP T2*).
Methods: Healthy volunteers (n=22) and patients with iron overload (n=78) were recruited (53 males, median age 34 years). A 1.5T study (Magnetom Avanto, Siemens) was performed on all subjects. The same mid-ventricular short axis cardiac slice and transaxial slice through the liver were used to acquire both RBH T2* images and WIP T2* maps for each participant. Cardiac white blood (WB) and black blood (BB) sequences were acquired. Intraobserver, interobserver and interstudy reproducibility were measured on the same data from a subset of 20 participants.
Results: Liver T2* values ranged from 0.8-35.7ms (median 5.1ms) and cardiac T2* values from 6.0-52.3ms (median 31ms). The coefficient of variance (CoV) values for direct comparison of T2* values by RBH and WIP were 6.1%-7.8% across techniques. Accurate delineation of the septum was difficult on some WIP T2* maps due to artefacts. The inability to manually correct for noise by truncation of erroneous later echo times led to some overestimation of T2* using WIP T2* compared with the RBH T2*. Reproducibility CoV results for RBH T2* ranged from 1.5%–5.7% which were better than the reproducibility of WIP T2* values of 4.1%–16.6%.
Conclusions: Iron estimation using the T2* CMR sequence in combination with Siemens’ in-line data processing is generally satisfactory and may help facilitate global access to tissue iron assessment. The current automated T2* map technique is less good for tissue iron assessment with noisy data at low T2* values.