Post, N. (Nicoline) (2016) Phantom study: The accuracy of IDEAL-IQ, a new MRI technique, by GE Healthcare to diagnose and monitor NAFLD. thesis, Medicine.
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Abstract
Non-alcoholic fatty liver disease is a widespread disease with a prevalence of 10-30% in the Western world and 12-24% in developed Asian countries. Risk factors for NAFLD are obesity, DM2 and metabolic syndrome. Middle-aged female patients develop NAFLD the most. Above 5% triglyceride fraction in the liver is histopathologically diagnosed as fatty 4 liver. NAFLD can be categorized in two groups: benign and non-progressive NAFL and progressive NASH which can lead to HCC (hepatocellular carcinoma). The Golden standard for diagnosing NAFLD is the liver biopsy. Although minimal invasive, the liver biopsy brings risks for the patients well-being. Therefore different ways of diagnosing NAFLD should be considered. Non-invasive techniques have been developed to measure the fat fraction and correct for T2 decay. GE Healthcare developed the IDEAL-IQ method, which can quantify fat fraction as well as R2*. R2*= 1/T2* and T2* is used to measure the amount of iron. The purpose of this research is to investigate the accuracy of IDEAL-IQ for measuring the fat fractions and R2* values. We have also investigated the limitations and advances of IDEAL-IQ. We constructed 33 phantoms with different fat fractions and iron levels. These fractions and levels are within the range of healthy livers up to the range of livers with NAFLD and iron overload. For the construction we have prepared a water solution and used 100% peanut oil and SPIO (resovist inj.). We made a protocol based on Bernard et al. and trial and error. The measurement of the fat fraction was performed by IDEAL-IQ and MR spectroscopy. The fat content of the phantoms were used as the Golden standard. The measurement of R2* was also performed by IDEAL-IQ. The Golden standard for the R2* values were calculated by the fat-peak of the MRS graphs. In total 3 scans were performed. Scan one was not accurate. Scan two showed accurate results. IDEAL-IQ measured fat fractions showed a strong correlation with the Golden standard, for iron levels of 0 and 10 μg/ml: intercepts of 0.59 and 1.23 and slopes of 1.09 and 1.06. Compared with the MRS results the IDEAL-IQ results showed to be more accurate for iron levels of 10 and 20 μg/ml (intercepts of 10.08 and 23.95 and slopes of 0.42 and -0.34 compared with intercepts of 1.23 and 2.24 and slopes of 1.06 and 1.17 for the IDEAL-IQ method). A high amount of iron results in a higher amount of measured fat fraction compared with the Golden standard. IDEAL-IQ R2* values were fairly correlated with the Golden standard, intercept of -13.65 and slope of 1.21. The fat fraction also seems to influence the measured amount of R2*. A high fat fraction results in a higher amount of measured R2* compared with the Golden standard. Limitations of the IDEAL-IQ are the fairly accurate R2* measurements and artifacts that tend to occur when the iron level is high (>20 μg/ml). Advances of the IDEAL-IQ are the accurate measured fat fractions and the high ROI.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | First mentor: and Sijens, Dr. P.E. Associate Professor University of Groningen |
| Supervisor name: | Second mentor: and Hori, Dr. M. Radiologist Handai Osaka and Research clerkship was performed at the University of Osaka |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 11:02 |
| Last Modified: | 25 Jun 2020 11:02 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/2233 |
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