CT vs MRI in stroke

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Authors: Mikael Häggström; Authors if integrated Creative Commons article[1] [notes 1]

Several studies have been conducted to determine the “best” imaging modality in acute stroke, but the reality is that both CT and MRI will co-exist and complement each other for a long time. The main drawbacks to CT are that an ischemic brain stroke may not appear in a CT scan for up to 48 hours period, and that CT does not image the vertebra-basilar (up to 15% of strokes). While the MRI does provide superior quality of images and anatomical details, in an acute setting its advantages address the above-mentioned two drawbacks of CT. Important contraindications to MRI are patients with magnetic material in their body such as pacemakers, pins, a vital point to note as neurologically altered or aphasic patients may be unable to provide this information to their providers.[1]

The sensitivities and specificities were 100% and 86%, respectively, for diffusion-weighted MR imaging versus 18% and 100% for conventional MR imaging and 45% and 100% for CT . New guidelines from the American Academy of Neurology state that doctors should use a diffusion MRI scan to diagnose stroke instead of a CT scan which was published in the July 13, 2010, issue of Neurology®, the medical journal of the American Academy of Neurology. The imaging modality of choice will depend upon the specific situation: cost, availability, clinical setting, contraindications etc. and it remains the purview of a well-educated provider to determine the imaging to effectively guide the therapeutic goals.[1]

Table 1: CT vs MRI[1]
Characteristic CT MRI
Availability Easily available in the emergency department Not available in all emergency departments
Time 5 mins 15 mins
Perfusion study: volume assessed 2–4 cm Entire brain visualized
Side effects: Contrast Iodinated contrast has toxic effects on kidney, cannot be used in renally compromised patients, risk of anaphylaxis. Gadolinium: minimal toxicity on kidneys, risk of nephrogenic and systemic fibrosis
Side effects: Ionizing radiation YES: increases risk of cancer No ionizing radiation
Side effects: Claustrophobia - +++
Drawback: motion artefact + +++
Contraindication: Pacemaker, shrapnel, metal plates - +++
Purpose
Chronic hemorrhage +/- +++
Acute ischemic stroke - ++
Angiography ++ +++
Vertebro-basilar visualization - ++
Abbreviations: ICH: Intracerebral hemorrhage, SAH: Sub arachnoid hemorrhage, EDH: Extradural hemorrhage, SDH: Subdural hemorrhage. AVM: Arterio-venous malformation, TCD: transcranial Doppler, CDUS: Carotid duplex ultrasound, DSA: Digital subtraction Angiography.

See also

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.

References

  1. 1.0 1.1 1.2 1.3 Shazia Mirza and Sankalp Gokhale (2016-07-25). Neuroimaging in Acute Stroke.
    Attribution 4.0 International (CC BY 4.0)