MCA dot sign (brain)

Last revised by Rohit Sharma ◉ on 14 Feb 2024

Citation, DOI, disclosures and article data

Citation:

Gaillard F, Sharma R, Elfeky M, et al. MCA dot sign (brain). Reference article, Radiopaedia.org (Accessed on 21 Mar 2025) https://doi.org/10.53347/rID-11092

DOI:

https://doi.org/10.53347/rID-11092

Permalink:

https://radiopaedia.org/articles/11092?embed_domain=hackmd.io%2525252F%25252540yIPUAFeCSL2JsU8smR5nJQ%2525252Fbnjhjgjghjghjghfavicon.ico

rID:

11092

Article created:

16 Oct 2010, Frank Gaillard ◉ ◈

Disclosures:

At the time the article was created Frank Gaillard had no recorded disclosures.

View Frank Gaillard's current disclosures

Last revised:

14 Feb 2024, Rohit Sharma ◉

Disclosures:

At the time the article was last revised Rohit Sharma had no financial relationships to ineligible companies to disclose.

View Rohit Sharma's current disclosures

Revisions:

23 times, by 15 contributors - see full revision history and disclosures

Systems:

Vascular, Central Nervous System

Sections:

Signs

Synonyms:

Middle cerebral artery dot sign
Middle cerebral artery (MCA) dot sign
Middle cerebral arterial dot sign

The middle cerebral artery (MCA) dot sign, also known as the Sylvian fissure sign, is a type of hyperdense vessel sign seen on non-contrast brain CT and represents the cross-sectional M2 equivalent of the hyperdense MCA sign. Rather than imaging a length of middle cerebral artery (typically the M1 segment), the dot sign represents a thromboembolism within a segmental branch of the MCA located within the Sylvian fissure (M2 segment). The sign appears when the high-attenuation MCA is viewed in axial section, since the occluded vessel courses in a plane perpendicular to the transverse plane of imaging.

Pathology

The MCA dot sign is an early marker of thromboembolic occlusion of the distal MCA branches seen in the Sylvian fissure (M2 segment). The principally affected area of the brain is the insula.

Sensitivity and specificity

The sensitivity of this CT sign is approximately 35%, while its specificity may be as high as 100% ³.

Treatment and prognosis

The MCA dot sign is prognostic of poor outcome in patients with ischaemic stroke, but with a better outcome than the hyperdense MCA sign ².

As such, single studies have assessed the possibility of automated detection ⁴and its value in prediction of secondary symptomatic intracranial haemorrhage ⁵.

Punctate vascular calcification along the M2 segment of the MCA within the Sylvian fissure represents a potential mimic of this sign.