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Original research
The hyperdense vessel sign on CT predicts successful recanalization with the Merci device in acute ischemic stroke
  1. Michael T Froehler1,
  2. Satoshi Tateshima2,
  3. Gary Duckwiler2,
  4. Reza Jahan2,
  5. Nestor Gonzalez2,3,
  6. Fernando Vinuela2,
  7. David Liebeskind4,
  8. Jeffrey L Saver3,
  9. J Pablo Villablanca5,
  10. For the UCLA Stroke Investigators
  1. 1Neuro Interventional Service, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA
  2. 2Division of Interventional Neuroradiology, UCLA, Los Angeles, California, USA
  3. 3Department of Neurosurgery, UCLA, Los Angeles, California, USA
  4. 4UCLA Stroke Center, Los Angeles, California, USA
  5. 5Division of Diagnostic Neuroradiology, UCLA, Los Angeles, California, USA
  1. Correspondence to Dr Michael T Froehler, Department of Neurology, University of Iowa Hospital, 200 Hawkins Drive, Iowa City, IA 52242, USA; michael-froehler{at}


Background The success of mechanical clot retrieval for acute ischemic stroke may be influenced by the characteristics of the occlusive thrombus. The thrombus can be partly characterized by CT, as the hyperdense vessel sign (HVS) suggests erythrocyte-rich clot whereas fibrin-rich clot may be isodense. We hypothesized that the physical clot characteristics that determine CT density may also determine likelihood of retrieval with the Merci device.

Methods We reviewed all acute stroke cases initially imaged with non-contrast CT before attempted Merci clot retrieval at a single center between 2004 and 2010. Each CT was blindly assessed for the presence or absence of the HVS, and post-retrieval angiograms were blindly assessed for reperfusion using the TICI scale.

Results Of 67 patients analyzed (mean age 69; median NIHSS 19; 61% female), the HVS was seen in 42, and no HVS was present in 25. Successful recanalization was achieved in 79% of patients with the HVS (33/42), but in only 36% (9/25) of patients without HVS (p=0.001). The HVS was the only significant predictor of recanalization while accounting for age, treatment with IV-tPA, clot location, stroke etiology, time to treatment, and number of retrieval attempts.

Conclusion The HVS in acute ischemic stroke was strongly predictive of successful recanalization using the Merci device. The HVS may indicate thrombi that are less adhesive compared with isodense clots that are more resistant to mechanical retrieval. The absence of HVS on pre-treatment CT may thus suggest the need for a more aggressive or alternative therapeutic approach.

  • Hyperdense vessel sign
  • clot retrieval
  • acute ischemic stroke
  • thrombus
  • recanalization
  • stroke
  • thrombectomy
  • thrombolysis
  • aneurysm
  • angioplasty
  • arteriovenous malformation
  • flow diverte r
  • artery
  • vein
  • vasculitis
  • complication
  • catheter
  • balloon
  • stent
  • stenosis
  • malformation
  • intervention
  • embolic
  • coil
  • brain
  • atherosclerosis
  • angioplasty
  • angiography
  • arteriovenous malformation
  • subarachnoid
  • stroke

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  • Funding Dr Froehler was supported by the A P Giannini Foundation. Dr Gonzalez was supported by the Ruth and Raymond Stotter Endowement. Dr Liebeskind receives funding from the NIH, including grants K24 NS072272-01, K23 NS054084-05, P50 NS044378-06. Dr. Villablanca receives funding from the NIH, including grants U01 NS044364, P50 NS044378, and from the NINDS U01- NS052220.

  • Competing interests Drs Tateshima, Duckwiler, Jahan, Gonzalez, Vinuela, Liebeskind, Saver, and Villablanca are employees of the University of California which holds patent rights in retrieval devices for stroke. Dr. Tateshima has received honoraria from Concentric Medical, the maker of the Merci device, and from Century Medical, the Japanese distributor of the Merci device. Drs. Duckwiler and Liebeskind serve as scientific advisors for Concentric Medical.

  • Ethics approval Ethics approval statement was approved by UCLA IRB.

  • Provenance and peer review Not commissioned; externally peer reviewed.