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  • Journal article
    Ismail TF, Jabbour A, Gulati A, Mistry N, Abdel-Malek M, Hewins B, Wage R, Roughton M, Ferreira PF, Gatehouse PD, Firmin DN, Pennell DJ, Kellman P, Prasad SKet al., 2013,

    Role of T1 and T2-mapping in assessing the myocardial interstitium in hypertrophic cardiomyopathy: a cardiovascular magnetic resonance study

    , Journal of Cardiovascular Magnetic Resonance, Vol: 15, ISSN: 1097-6647
  • Journal article
    Yang GUANG, Hipwell J, Hawkes D, Arridge Set al., 2013,

    Numerical methods for coupled reconstruction and registration in digital breast tomosynthesis.

    , Annals of the British Machine Vision Association, Vol: 2013, Pages: 1-38

    Digital Breast Tomosynthesis (DBT) provides an insight into the fine details of normalfibroglandular tissues and abnormal lesions by reconstructing a pseudo-3D image of thebreast. In this respect, DBT overcomes a major limitation of conventional X-ray mam-mography by reducing the confounding effects caused by the superposition of breasttissue. In a breast cancer screening or diagnostic context, a radiologist is interested indetecting change, which might be indicative of malignant disease. To help automatethis task image registration is required to establish spatial correspondence between timepoints. Typically, images, such as MRI or CT, are first reconstructed and then registered.This approach can be effective if reconstructing using a complete set of data. However,for ill-posed, limited-angle problems such as DBT, estimating the deformation is com-plicated by the significant artefacts associated with the reconstruction, leading to severeinaccuracies in the registration.This paper presents a mathematical framework, which couples the two tasks andjointly estimates both image intensities and the parameters of a transformation. Underthis framework, we compare an iterative method and a simultaneous method, both ofwhich tackle the problem of comparing DBT data by combining reconstruction of a pairof temporal volumes with their registration.We evaluate our methods using various computational digital phantoms, uncom-pressed breast MR images, and in-vivo DBT simulations. Firstly, we compare both iter-ative and simultaneous methods to the conventional, sequential method using an affinetransformation model. We show that jointly estimating image intensities and parametrictransformations gives superior results with respect to reconstruction fidelity and regis-tration accuracy. Also, we incorporate a non-rigid B-spline transformation model intoour simultaneous method. The results demonstrate a visually plausible recovery of thedeformation w
  • Journal article
    Nielles-Vallespin S, Mekkaoui C, Gatehouse P, Reese TG, Keegan J, Ferreira PF, Collins S, Speier P, Feiweier T, Silva R, otherset al., 2013,

    In vivo diffusion tensor MRI of the human heart: Reproducibility of breath-hold and navigator-based approaches

    , Magnetic resonance in medicine, Vol: 70, Pages: 454-465
  • Journal article
    Ferreira PF, Gatehouse PD, Mohiaddin RH, Firmin DNet al., 2013,

    Cardiovascular magnetic resonance artefacts

    , Journal of Cardiovascular Magnetic Resonance, Vol: 15, Pages: 41-41
  • Journal article
    Ferreira PF, Nielles-Vallespin S, Gatehouse PD, de Silva R, Keegan J, Speier P, Feiweier T, Reese TG, Ismail TF, Scott A, otherset al., 2013,

    Improved navigator based diffusion tensor MRI of the human heart in vivo

    , Journal of Cardiovascular Magnetic Resonance, Vol: 15, Pages: W25-W25
  • Journal article
    Ferreira PF, Nielles-Vallespin S, Gatehouse PD, de Silva R, Keegan J, Speier P, Feiweier T, Reese TG, Ismail TF, Scott A, otherset al., 2013,

    Cardiac diffusion tensor imaging: helix angle (HA) healthy statistical average technique for HA quantification in vivo

    , Journal of Cardiovascular Magnetic Resonance, Vol: 15, Pages: W7-W7
  • Journal article
    McGill L-A, Ismail TF, Nielles-Vallespin S, Ferreira P, Scott AD, Roughton M, Kilner PJ, Ho SY, McCarthy KP, Gatehouse PD, otherset al., 2012,

    Reproducibility of in-vivo diffusion tensor cardiovascular magnetic resonance in hypertrophic cardiomyopathy

    , Journal of Cardiovascular Magnetic Resonance, Vol: 14, Pages: 86-86, ISSN: 1097-6647

    Background: Myocardial disarray is an important histological feature of hypertrophic cardiomyopathy (HCM) whichhas been studied post-mortem, but its in-vivo prevalence and extent is unknown. Cardiac Diffusion Tensor Imaging(cDTI) provides information on mean intravoxel myocyte orientation and potentially myocardial disarray. Recenttechnical advances have improved in-vivo cDTI, and the aim of this study was to assess the interstudyreproducibility of quantitative in-vivo cDTI in patients with HCM.Methods and results: A stimulated-echo single-shot-EPI sequence with zonal excitation and parallel imaging wasimplemented. Ten patients with HCM were each scanned on 2 different days. For each scan 3 short axismid-ventricular slices were acquired with cDTI at end systole. Fractional anisotropy (FA), mean diffusivity (MD), andhelix angle (HA) maps were created using a cDTI post-processing platform developed in-house. The mean ± SDglobal FA was 0.613 ± 0.044, MD was 0.750 ± 0.154 × 10-3 mm2/s and HA was epicardium −34.3 ± 7.6°,mesocardium 3.5 ± 6.9° and endocardium 38.9 ± 8.1°. Comparison of initial and repeat studies showed globalinterstudy reproducibility for FA (SD = ± 0.045, Coefficient of Variation (CoV) = 7.2%), MD (SD = ± 0.135 × 10-3 mm2/s,CoV = 18.6%) and HA (epicardium SD = ± 4.8°; mesocardium SD = ± 3.4°; endocardium SD = ± 2.9°). Reproducibilityof FA was superior to MD (p = 0.003). Global MD was significantly higher in the septum than the reference lateralwall (0.784 ± 0.188 vs 0.750 ± 0.154 x10-3 mm2/s, p < 0.001). Septal HA was significantly lower than the referencelateral wall in all 3 transmural layers (from −8.3° to −10.4°, all p < 0.001).Conclusions: To the best of our knowledge, this is the first study to assess the interstudy reproducibility of DTI inthe human HCM heart in-vivo and the largest cDTI stu
  • Journal article
    Gulati A, Krishnathasan K, Hsu L-Y, Ali A, Ismail T, Ferreira P, Ismail N, Goncalves C, Davendralingam N, Wage R, Roughton M, Gatehouse P, Jabbour A, Pennell DJ, Arai AE, Prasad Set al., 2012,

    Absolute Hyperemic Myocardial Blood Flow is Impaired in Non-Ischemic Dilated Cardiomyopathy and is Related to the Severity of Left Ventricular Systolic Dysfunction

    , CIRCULATION, Vol: 126, ISSN: 0009-7322
  • Journal article
    Grech-Sollars M, Saunders DE, Phipps KP, Clayden JD, Clark CAet al., 2012,

    Survival analysis for apparent diffusion coefficient measures in children with embryonal brain tumours

    , NEURO-ONCOLOGY, Vol: 14, Pages: 1285-1293, ISSN: 1522-8517
  • Thesis dissertation
    Yang G, 2012,

    Numerical Approaches for Solving the Combined Reconstruction and Registration of Digital Breast Tomosynthesis

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