Images in Clinical Medicine: Hyperdense MCA Sign

Abstract

The MCA (HMCA) refers to the appearance, on computed tomography, of increased attenuation of the proximal portion of the middle cerebral artery (MCA) and is often associated with thrombosis of the M1 MCA segment. It is one of the early signs of ischemic stroke. CASE REPORT A 64-year old (R) handed female, with history of essential hypertension and type 2 diabetes mellitus, presented with 9hour history of abrupt onset of right-sided weakness and difficulty speaking. Emergent head CT scan demonstrated a thrombus occluding the main stem of the left middle cerebral artery (hyperdense MCA sign) (Fig 1). Thrombolytics being contraindicated given her late presentation, successful endovascular extraction of the thrombus was achieved with a MERCI device (Mechanical Embolus Removal in Cerebral Ischemia). Follow up head CT scan showed resolution of the dense MCA sign and hemorrhagic conversion of the ischemic stroke (Fig 2 & 3); despite aggressive management, patient still had significant right hemiparesis and expressive aphasia upon transfer to rehab. Figure 1 Figure 1: CT scan of the head showing a thrombus occluding the stem of the left MCA (hyperdense MCA sign) Images in Clinical Medicine: Hyperdense MCA Sign 2 of 4 Figure 2 Figure 2: CT scan head post mechanical clot extraction showing resolution of the hyperdense MCA sign Figure 3 Figure 3: CT scan of the head showing hemorrhagic conversion of the ischemic infarct after mechanical clot removal DISCUSSION The HMCA sign also called as MCA “dot” sign is one of the early signs of ischemic stroke along with loss of the insular ribbon, attenuation of the lentiform nucleus and hemispherical sulcus effacement 1 .It may be the only diagnostic feature on computed tomography early after ischemic stroke. Various studies have been conducted to determine its incidence, diagnostic value, and reliability 2. False positives are recognized, and correct recognition of this sign has therefore, assumed greater importance especially with the advent of thrombolytic therapy for stroke 3. CORRESPONDENCE TO Nitin Sethi, M.D. Chief Resident, Neurology Saint Vincent's Hospital and Medical Centers 153 West, 11th Street New York, NY 10011 Email: sethinitinmd@hotmail.com