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  • Journal article
    Yiannakas MC, Wheeler-Kingshott CAM, Berry AM, Chappell K, Henderson A, Kolappan M, Miller DH, Tozer DJet al., 2010,

    A Method for Measuring the Cross Sectional Area of the Anterior Portion of the Optic Nerve In Vivo Using a Fast 3D MRI Sequence

    , JOURNAL OF MAGNETIC RESONANCE IMAGING, Vol: 31, Pages: 1486-1491, ISSN: 1053-1807
  • Journal article
    Barral JK, Bangerter NK, Hu BS, Nishimura DGet al., 2010,

    In vivo high-resolution magnetic resonance skin imaging at 1.5 T and 3 T

    , Magnetic Resonance in Medicine, Vol: 63, Pages: 790-796, ISSN: 0740-3194
  • Journal article
    Gatehouse PD, Rolf MP, Graves MJ, Hofman MBM, Totman J, Werner B, Quest RA, Liu Y, von Spiczak J, Dieringer M, Firmin DN, van Rossum A, Lombardi M, Schwitter J, Schulz-Menger J, Kilner PJet al., 2010,

    Flow measurement by cardiovascular magnetic resonance: a multi-centre multi-vendor study of background phase offset errors that can compromise the accuracy of derived regurgitant or shunt flow measurements

    , Journal of Cardiovascular Magnetic Resonance, Vol: 12, ISSN: 1097-6647

    AimsCardiovascular magnetic resonance (CMR) allows non-invasive phase contrast measurements of flow through planes transecting large vessels. However, some clinically valuable applications are highly sensitive to errors caused by small offsets of measured velocities if these are not adequately corrected, for example by the use of static tissue or static phantom correction of the offset error. We studied the severity of uncorrected velocity offset errors across sites and CMR systems.Methods and ResultsIn a multi-centre, multi-vendor study, breath-hold through-plane retrospectively ECG-gated phase contrast acquisitions, as are used clinically for aortic and pulmonary flow measurement, were applied to static gelatin phantoms in twelve 1.5 T CMR systems, using a velocity encoding range of 150 cm/s. No post-processing corrections of offsets were implemented. The greatest uncorrected velocity offset, taken as an average over a 'great vessel' region (30 mm diameter) located up to 70 mm in-plane distance from the magnet isocenter, ranged from 0.4 cm/s to 4.9 cm/s. It averaged 2.7 cm/s over all the planes and systems. By theoretical calculation, a velocity offset error of 0.6 cm/s (representing just 0.4% of a 150 cm/s velocity encoding range) is barely acceptable, potentially causing about 5% miscalculation of cardiac output and up to 10% error in shunt measurement.ConclusionIn the absence of hardware or software upgrades able to reduce phase offset errors, all the systems tested appeared to require post-acquisition correction to achieve consistently reliable breath-hold measurements of flow. The effectiveness of offset correction software will still need testing with respect to clinical flow acquisitions.
  • Thesis dissertation
    Ferreira PFADC, 2010,

    First-pass myocardial perfusion MRI: artifacts and advances
  • Journal article
    de Llano SRM, Perry R, Waldman A, Murphy D, Edison P, Okello A, Turkeimer F, Bose S, Quest R, Brooks Det al., 2009,

    In- vivo diagnosis of atypical Alzheimer disease using pathology-sensitive brain imaging, 11C-PIB and short TE spectroscopy MR imaging in Posterior Cortical Atrophy

    , EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, Vol: 36, Pages: S244-S244, ISSN: 1619-7070
  • Conference paper
    de Llano SRM, Perry R, Waldman A, Murphy D, Edison P, Okello A, Turkeimer F, Bose S, Quest R, Brooks Det al., 2009,

    In- vivo diagnosis of atypical Alzheimer disease using pathology-sensitive brain imaging, 11C-PIB and short TE spectroscopy MR imaging in Posterior Cortical Atrophy

    , Publisher: SPRINGER, Pages: 244-244, ISSN: 1619-7070
  • Journal article
    Gold GE, Chen CA, Koo S, Hargreaves BA, Bangerter NKet al., 2009,

    Recent Advances in MRI of Articular Cartilage

    , American Journal of Roentgenology, Vol: 193, Pages: 628-638, ISSN: 0361-803X
  • Journal article
    Çukur T, Lee JH, Bangerter NK, Hargreaves BA, Nishimura DGet al., 2009,

    Non‐contrast‐enhanced flow‐independent peripheral MR angiography with balanced SSFP

    , Magnetic Resonance in Medicine, Vol: 61, Pages: 1533-1539, ISSN: 0740-3194

    <jats:title>Abstract</jats:title><jats:p>Flow‐independent angiography is a non‐contrast‐enhanced technique that can generate vessel contrast even with reduced blood flow in the lower extremities. A method is presented for producing these angiograms with magnetization‐prepared balanced steady‐state free precession (bSSFP). Because bSSFP yields bright fat signal, robust fat suppression is essential for detailed depiction of the vasculature. Therefore, several strategies have been investigated to improve the reliability of fat suppression within short scan times. Phase‐sensitive SSFP can efficiently suppress fat; however, partial volume effects due to fat and water occupying the same voxel can lead to the loss of blood signal. In contrast, alternating repetition time (ATR) SSFP minimizes this loss; however, the level of suppression is compromised by field inhomogeneity. Finally, a new double‐acquisition ATR‐SSFP technique reduces this sensitivity to off‐resonance. In vivo results indicate that the two ATR‐based techniques provide more reliable contrast when partial volume effects are significant. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.</jats:p>
  • Journal article
    Ferreira P, Gatehouse P, Kellman P, Bucciarelli-Ducci C, Firmin Det al., 2009,

    Variability of myocardial perfusion dark rim Gibbs artifacts due to sub-pixel shifts

    , Journal of Cardiovascular Magnetic Resonance, Vol: 11, Pages: 17-17
  • Conference paper
    Morrell MJ, Jackson ML, Twigg G, Ghiassi R, McRobbie DW, Quest RA, Pardoe H, Pell GS, Abbott DF, Roachford PD, Pierce RJ, O'Donoghue FJ, Corfield DRet al., 2009,

    Changes in Brain Morphology Associated with Obstructive Sleep Apnea (OSA)

    , Publisher: AMER THORACIC SOC, ISSN: 1073-449X

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For enquiries about the MRI Physics Collective, please contact:

Mary Finnegan
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Pete Lally
Assistant Professor in Magnetic Resonance (MR) Physics at Imperial College

Jan Sedlacik
MR Physicist at the Robert Steiner MR Unit, Hammersmith Hospital Campus