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HEADLINE: Late-enhancement MRI finds diagnostic roles ...

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  • HEADLINE: Late-enhancement MRI finds diagnostic roles ...

    Copyright 2003 CMP Media LLC

    Diagnostic Imaging

    May 1, 2003

    SECTION: SPECIAL SECTION: SCMR CONFERENCE REPORTER; Pg. 67

    LENGTH: 1218 words

    HEADLINE: Late-enhancement MRI finds diagnostic roles -- Tests outperform PET
    and SPECT in studies presented at SCMR meeting

    BYLINE: James Brice

    HIGHLIGHT:
    Radiologists have long held great expectations for cardiac MRI in the diagnosis
    of coronary artery disease. Its developers envisioned comprehensive applications
    encompassing the diagnosis of myocardial infarction, detection and measurement
    of coronary artery stenoses, and assessment of myocardial viability.

    BODY:

    Overcoming MRI's poor temporal resolution to realize that vision has proved
    difficult, however. Despite some progress, coronary artery MRA is still not
    ready to challenge x-ray angiography, and although first-pass perfusion MRI may
    match the accuracy of stress echocardiography and thallium-201 SPECT, it remains
    difficult to perform.

    These shortcomings provided an opening for MRI myocardial viability
    assessment. Since 1997, studies by Dr. Charles Higgins, Dr. Robert M. Judd, Dr.
    Raymond Kim, Dr. Christoph Klein, Dr. Joao A. Lima, and Dr. Jorn J. Sandstede
    and others have shown that late-enhancement MRI accurately predicts whether
    patients will benefit from revascularization.

    Dr. Ernest E. Van der Wall, a professor of cardiovascular radiology at the
    University of Leiden in the Netherlands, said at the SCMR meeting that the
    clinical efficacy of delayed-enhancement MRI is no longer in doubt.

    "Bright is dead," he said, referring to the hyperenhanced depiction of
    myocardial infarction on late-enhancement images.

    Other studies reported at the SCMR meeting reinforced that conclusion and
    suggested that late enhancement can play other roles.

    Dr. Peter Hunold, a resident in radiology at University Hospital in Essen,
    Germany, presented a study of 12 CAD patients in which late-enhancement MRI was
    shown to be more specific and to have a higher positive predictive value than
    FDG-PET for predicting the success of revascularization. No significant
    difference in negative predictive values for the two modalities was seen.

    Based on the evaluation of 1008 myocardial segments, the sensitivity and
    specificity of MRI for predicting functional recovery was 95% and 72%,
    respectively. The FDG-PET results for these measures were 97% and 47%,
    respectively.

    "The specificity of MRI is not optimal, but it is remarkably higher than PET,
    because MRI is generally less optimistic than PET," Hunold said.

    The PPV and NPV for regional myocardial improvement were 66% and 96% for MRI
    and 52% and 97% for PET.

    "Our answer to the question whether MRI should be the new gold standard for
    myocardial viability would certainly be 'yes,'" he said.

    SPECT COMPARISON

    In a study of 53 patients with left ventricular dysfunction following MI, Dr.
    Matthias Regenfus, a cardiovascular radiology researcher at Frederick Alexander
    University in Erlangen Nurnberg, Germany, found a close correlation between
    late-enhancement contrast-enhanced MRI and thallium-201 SPECT for evaluation of
    myocardial viability. The segmental extent of infarction was significantly less
    pronounced on the SPECT studies, however, and SPECT failed to identify 70 of 352
    myocardial segments that hyperenhanced on CE-MRI.

    Regenfus credited CE-MRI's relatively high spatial resolution for its
    superior performance.

    "It allows late-enhancement CE-MRI to better depict the transmural extent of
    myocardial infarction and detect small myocardial necroses that escape detection
    with SPECT," he said.

    Research from Duke University indicates that CE-MRI may be a better way to
    diagnose silent MI, according to Dr. Han Kim, a cardiovascular MRI research
    fellow.

    The hypothesis that CE-MRI may be more sensitive to silent MI than
    Q-wave/non-Q-wave ECG, the current diagnostic gold standard, was supported by a
    study of 100 patients with suspected silent MI. Hyperenhancement of infarction
    with CE-MRI was observed in 57% of the cases, a rate four times higher than the
    14% rate of unrecognized MI detected with the Q-wave test, Kim said.

    Follow-up evaluations after an average of 21 months found that the extent of
    hyperenhancement was the only statistically significant predictor of death (p =
    0.002). The risk of death rose when the hyperenhanced infarction involved more
    than 5% of the left ventricular myocardium.

    Several studies at the SCMR conference examined how to distinguish acute from
    chronic MI with CE-MRI. Dr. Hassan Abdel-Aty, a cardiology researcher at the
    Franz-Vohard Clinic in Berlin, found that late-enhancement imaging combined with
    short T1 inversion recovery (STIR) imaging can play that role.

    In a study of 119 patients (74 with acute MI, 27 with chronic MI, and 18
    healthy controls), late-enhancement MRI was 100% sensitive to infarction but was
    unable to differentiate acute from chronic disease. STIR, however, revealed
    transmural hyperintensity among 71 of 74 acute infarcts and no transmurality
    among the chronic lesions. The sensitivity and specificity of the paired tests
    were 96% and 100%, respectively.

    IMAGING CARDIOMYOPATHY

    Late-enhancement CE-MRI may also find a role in the diagnosis of
    cardiomyopathies. Dr. Marcelo Hadlich, a radiology researcher associated with
    the D'Or Hospital Network in Rio de Janeiro, Brazil, reported that
    delayed-enhancement MRI can detect irreversible myocardial disease in patients
    with myopericarditis.

    A preliminary study of five patients found delayed hyperenhancement in 40% of
    the left ventricular segments examined. Those areas were small, diffusely
    distributed, and not restricted to any specific coronary territories, Hadlich
    said. The same hyperenhancement appeared when imaging was repeated three months
    later, suggesting irreversible myocardial injury.

    The work of Dr. James C.C. Moon and colleagues at Royal Brompton Hospital in
    London, U.K., suggests that cine CMR and CE-MRI myocardial hyperenhancement may
    diagnose early hypertrophic cardiomyopathy and serve as a marker for clinical
    risk.

    In a study of 30 patients from 13 families with mutations of troponin I,
    echocardiography found hyperenhancement (LVH+) and exaggerated wall thickness in
    15 subjects, and no abnormal enhancement and normal wall thickness among 15
    (LVH-) individuals who are either in the early stages or disease-free.

    Abnormal cine CMR and abnormal regional hypertrophy were found in 100% of the
    LVH+ and 27% of the LVH- subjects. Hyperenhancement appeared in 86% of the LVH+
    and 20% of the LVH- groups.

    The overall extent of hyperenhancement was related to the risk of sudden
    death and total left ventricular mass, and it was inversely related to left
    ventricular ejection fracture, Moon said.

    Although no age-related pattern was observed for the group as a whole,
    hyperenhancement increased with age compared with the subjects' family members.
    This pattern suggests that increasing hyperenhancement patterns over time
    reflect disease progression, he said.

    Chagas disease, also called South American trypanosomiasis, is caused by a
    blood-borne parasite and can lead to myocardial fibrosis, typically in apical
    and basal inferolateral left ventricular segments. Dr. Carlos E. Rochitte at the
    Heart Institute of the University of Sao Paulo Medical School in Brazil found
    that delayed-enhancement MRI identified fibrosis in 22 of 25 Chagas disease
    patients and in 31% of the myocardial segments that were observed. More midwall
    and subepicardial involvement was documented than was considered typical with
    the disease. The extent of myocardial fibrosis correlated well with left
    ventricular ejection fraction.

    Although more investigative work is needed to refine these applications,
    late-enhancement CE-MRI is quickly gaining favor among researchers responsible
    for the creation and development of cardiac MRI.

    Copyright (c) 2003 CMP Media LLC

    LOAD-DATE: June 9, 2003
    Thanks, Tim
    Forum Administrator

  • #2
    Re: HEADLINE: Late-enhancement MRI finds diagnostic roles ..

    This looks very interesting...but remember this is looking at MI patients not cardiomyopathys...so it is a little different.
    Lisa
    Knowledge is power ... Stay informed!
    YOU can make a difference - all you have to do is try!

    Dx age 12 current age 46 and counting!
    lost: 5 family members to HCM (SCD, Stroke, CHF)
    Others diagnosed living with HCM (or gene +) include - daughter, niece, nephew, cousin, sister and many many friends!
    Therapy - ICD (implanted 97, 01, 04 and 11, medication
    Currently not obstructed
    Complications - unnecessary pacemaker and stroke (unrelated to each other)

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