Page 18 - Rob Holtackers
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| Chapter 1

            subendocardial.  Due to the almost equally bright signal of the adjacent blood pool,
            detection of these small areas of ischemic scar is challenging (Figure 1.6). Even when
            successfully  detecting  such  areas,  identifying  the  exact  scar-blood  border  remains
            difficult.  Scar  can  be  interpreted  as  part  of  the  blood  pool  and  can  therefore
            significantly  reduce,  or  even  completely  obscure  the  apparent  scar  volume.  On  the
            other hand, scar tissue can be mimicked by the blood pool signal and therefore result
            in false positive observations.

            Figure 1.6: Conventional short-axis (bright-blood) LGE images of three patients with suspicion of
            myocardial infarction (cyan arrows). Due to the almost equally high signal of the blood pool,
            poor  scar-to-blood  contrast  results  which  hampers  the  detection  and  assessment  of  areas  of
            subendocardial scar.

            Dark-blood LGE
            Already  more  than  15  years  ago,  advances  were  made  to  increase  scar-to-blood
            contrast  using  various  additional  magnetization  preparation  mechanisms.  This  need
            was further strengthened after discovering that even tiny regions of scar tissue of only
            2% of the mean left ventricular mass were linked with a sevenfold increase in major
            cardiac events,  and that scar transmurality plays a major role in the prediction of the
            likelihood  of  regional  functional  recovery  after  revascularization.   Furthermore,
            increased  scar-to-blood  contrast  may  be  beneficial  for  identifying  papillary  muscle
            scar  and assessing thin-walled structures, such as the right ventricle and atria.  Over
            the  years,  various  new  LGE  approaches  have  emerged  that  aimed  to  improve
            subendocardial scar conspicuity. 31-44  Although these LGE methods achieved superior
            scar-to-blood contrast compared to conventional LGE, the majority required additional
            magnetization preparation schemes, including T 2 preparation, magnetization transfer,
            and spin locking. Such additional schemes require (1) adjustments to the MR system
            software  and/or  configuration,  (2)  extensive  optimizations  for  new  sequence
            parameters,  (3)  additional  training  for  radiographers,  and  therefore  hamper  direct
            translation to routine clinical practices.

            Aims and outline of this thesis

            The main aim of this PhD thesis was to develop a novel blood-suppressed (dark-blood)
            LGE  method  that  achieves  superior  scar-to-blood  contrast  without  requiring  any
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