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7 results

  • The Value of Neurological Assessment for Prediction of Subtle Cerebral Infarction

  • Anat Horev, Yonatan Serlin, Ron Eshel, Ronen Leker, Michael Star, Asaf Honig, Gal Ifergane
  • Journal:
    Canadian Journal of Neurological Sciences / Volume 48 / Issue 2 / March 2021
    Published online by Cambridge University Press:
    29 July 2020, pp. 275-277
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  • We examined to what extent clinical assessment alone can predict subtle acute cerebral infarction on magnetic resonance imaging (MRI). Of the 72 patients presented to the emergency department (ED) with transient neurological deficits, 26 (36.1%) were predicted to be “positive” and 46 (63.9%) “negative” for transient ischemic attack/minor stroke by two independent neurologists. Twenty patients (27.8%) had acute restricted diffusion on MRI. Clinical assessment showed substantial agreement with MRI findings (Kappa = 0.75), sensitivity (95.0%), specificity (86.5%), positive-likelihood ratio 7.06, and negative-likelihood ratio 0.06. Neurological assessment has an excellent predicting value for MRI-confirmed acute cerebral infarction and a key role in the facilitation of effective patient care in the ED.

  • Qualitative Posttreatment Diffusion-Weighted Imaging as a Predictor of 90-day Outcome in Stroke Intervention

  • Adam A Dmytriw, Abdullah Alrashed, Alejandro Enriquez-Marulanda, Shadi Daghighi, Ghouth Waggas, Aria Rezaie, Chinthaka Heyn, Amy Yu, Richard I Aviv, Leodante Da Costa, Victor XD Yang
  • Journal:
    Canadian Journal of Neurological Sciences / Volume 47 / Issue 2 / March 2020
    Published online by Cambridge University Press:
    29 November 2019, pp. 160-166
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  • Purpose:

    The aim was to assess the ability of post-treatment diffusion-weighted imaging (DWI) to predict 90-day functional outcome in patients with endovascular therapy (EVT) for large vessel occlusion in acute ischemic stroke (AIS).

    Methods:

    We examined a retrospective cohort from March 2016 to January 2018, of consecutive patients with AIS who received EVT. Planimetric DWI was obtained and infarct volume calculated. Four blinded readers were asked to predict modified Rankin Score (mRS) at 90 days post-thrombectomy.

    Results:

    Fifty-one patients received endovascular treatment (mean age 65.1 years, median National Institutes of Health Stroke Scale (NIHSS) 18). Mean infarct volume was 43.7 mL. The baseline NIHSS, 24-hour NIHSS, and the DWI volume were lower for the mRS 0–2 group. Also, the thrombolysis in cerebral infarction (TICI) 2b/3 rate was higher in the mRS 0–2 group. No differences were found in terms of the occlusion level, reperfusion technique, or recombinant tissue plasminogen activator use. There was a significant association noted between average infarct volume and mRS at 90 days. On multivariable analysis, higher infarct volume was significantly associated with 90-day mRS 3–5 when adjusted to TICI scores and occlusion location (OR 1.01; CI 95% 1.001–1.03; p = 0.008). Area under curve analysis showed poor performance of DWI volume reader ability to qualitatively predict 90-day mRS.

    Conclusion:

    The subjective impression of DWI as a predictor of clinical outcome is poorly correlated when controlling for premorbid status and other confounders. Qualitative DWI by experienced readers both overestimated the severity of stroke for patients who achieved good recovery and underestimated the mRS for poor outcome patients. Infarct core quantitation was reliable.

  • Chapter 19.2 - Congenital diaphragmatic hernia

  • from Section 2 - Fetal disease
  • Edited by Mark D. Kilby, Anthony Johnson, Baylor College of Medicine, Texas, Dick Oepkes
  • Book:
    Fetal Therapy
    Published online:
    05 February 2013
    Print publication:
    13 December 2012, pp 376-388

  • Summary

    This chapter discusses congenital diaphragmatic hernia (CDH) from a perspective of antenatal management, including fetal intervention. It summarizes actual survival rates when this condition is managed after birth, essentially showing that there is no effective postnatal therapy in a subset of fetuses. Prediction methods are typically based on estimation of lung size by ultrasound and determination of liver herniation into the thorax. Three-dimensional (3D) ultrasound (US) and MRI both allow measurement of absolute lung volumetry. MRI allows better visualization of the ipsilateral lung than 3D US. Preliminary work on the use of diffusion-weighted imaging (DWI)-MRI as a tool to differentiate between normal and pathological lung development has shown a significant relationship between DWI-MRI parameters and gestational age in the normal fetus. The chapter also describes the current clinical experience with fetal surgery, including the design of trials that will have to determine the place of fetal surgery.

  • 23 - Pharmacogenomics and related discovery-driven approaches in multiple sclerosis

  • from Section II - Clinical trial methodology
  • Edited by Jeffrey A. Cohen, Richard A. Rudick
  • Book:
    Multiple Sclerosis Therapeutics
    Published online:
    05 December 2011
    Print publication:
    20 October 2011, pp 272-286

  • Summary

    Early evaluations of multiple sclerosis (MS) with diffusion imaging focused on the most basic form of diffusion imaging, diffusion-weighted imaging (DWI), which is relatively easy to perform using only acquisitions in cardinal imaging planes. Diffusion tensor imaging (DTI) is employed to evaluate MS. The simplest non-spherical model of a full three-dimensional diffusion profile is described by a second-rank tensor. Useful mathematical parameters that emerge from the tensor include the geometric axes of the tensor ellipsoid, the mean diffusivity (MD), fractional anisotropy (FA), and the parallel and perpendicular diffusivity. Several investigators have proposed evaluating diffusion imaging data using voxel-wise comparisons (VWC). A new VWC method to address the issues of different smoothing algorithms is tract-based spatial statistics (TBSS). DTI is unique in its ability to identify white matter pathways in the brain. A recent study has demonstrated a high level of sensitivity for detection of disease progression in MS using DTI.

  • 5 - Technical introduction to MRI

  • Edited by Stephen Davis, Marc Fisher, National Institute of Mental Health, Bethesda, Maryland, Steven Warach, National Institutes of Health, Baltimore
  • Book:
    Magnetic Resonance Imaging in Stroke
    Published online:
    26 August 2009
    Print publication:
    20 March 2003, pp 55-68

  • Summary

    This chapter outlines the basic physical principles of magnetic resonance imaging (MRI), and overviews the MR techniques that have been developed for investigating stroke patients. Magnetic resonance angiography (MRA) is a major advance in application of MRI to imaging of patient blood flow in vessels. The signal intensity in MRI depends on proton density, T1, T2 and T2 relaxation process of any ensemble of the spins. Diffusion- and perfusion-weighted imaging combined with fast imaging capabilities on commercial systems has revolutionized our understanding of the pathophysiological mechanisms involved in the many clinical conditions especially cerebral ischemia and stroke. Another popular technique used for perfusion MR imaging is the arterial spin labelling (ASL). Magnetic resonance spectroscopy (MRS) of the brain is a noninvasive MR technique that gives the relative concentration of certain chemical compounds within 2 to 3 cm3 of tissue.

  • 14 - Clinical role of echoplanar MRI in stroke

  • Edited by Stephen Davis, Marc Fisher, National Institute of Mental Health, Bethesda, Maryland, Steven Warach, National Institutes of Health, Baltimore
  • Book:
    Magnetic Resonance Imaging in Stroke
    Published online:
    26 August 2009
    Print publication:
    20 March 2003, pp 175-190

  • Summary

    Stroke is a leading cause of death in Western countries, with a case mortality rate of 24% within the first month, higher than most forms of cancer. Echoplanar magnetic resonance imaging (EPI) enables rapid, non-invasive imaging and analysis of cerebral pathophysiology in acute stroke. Various functional imaging methods have been used in the evaluation of acute stroke. Positron emission tomography (PET) enables imaging and measurement of both perfusion and metabolism. At present, diffusion-weighted imaging (DWI) is the most used of the EPI parameters in clinical practice. DWI is both highly sensitive and specific for acute stroke. Magnetic resonance spectroscopy (MRS) allows the non-invasive assessment of metabolic changes during stroke. The addition of chemical shift imaging (CSI) to a multimodal acute stroke MRI examination may confer additional accuracy to the identification of at-risk ischemic tissue. EPI with DWI, PWI and MRS have now moved from the research arenainto routine clinical use.