Original Paper

Microembolic Signals within 24 Hours of Stroke Onset and Diffusion-Weighted MRI Abnormalities
Makoto Nakajima^a, Kazumi Kimura^b, Atsuko Shimode^a, Fumio Miyashita^a, Makoto Uchino^c, Hiroaki Naritomi^a, Kazuo Minematsu<sup>a

a</sup>Cerebrovascular Division, Department of Medicine, National Cardiovascular Center, Osaka,
^bStroke Center, Kawasaki Medical School, Kurashiki, and
^cDepartment of Neurology, Kumamoto University School of Medicine, Kumamoto, Japan

Address of Corresponding Author

Cerebrovasc Dis 2007;23:282-288 (DOI: 10.1159/000098328)

  Key Words

• Acute stroke
• Diffusion-weighted imaging
• Transcranial Doppler sonography
• Subcortical infarction

  Abstract

Background: The clinical relevance of the microembolic signals (MES) detected by transcranial Doppler sonography (TCD) in acute stroke remains unclear. In a prospective study the authors analyzed the relationship between MES and the findings on diffusion-weighted magnetic resonance imaging (DWI) in acute stroke patients. Methods: We performed TCD for a period of 30 min to detect MES in patients within 24 h of stroke onset, and DWI was done within the initial 7 days. MES were assessed from Doppler waves obtained from the middle cerebral artery contralateral to the side of the neurological deficits. The acute ischemic lesions observed on DWI were classified by their diameter (small, medium or large) and by their site (cortical, superficial perforator territory, internal borderzone or deep perforator territory). Results: We obtained Doppler waves from 39 vessels in 37 patients; 2 patients had bilateral deficits. MES were detected in 12 vessels (MES-positive group) and not detected in 27 vessels (MES-negative group). No significant differences in clinical features were observed between the 2 groups. The number of small lesions was significantly higher in the MES-positive group than in the MES-negative group (p = 0.02). The numbers of cortical and superficial perforator infarcts were significantly higher in the MES-positive group than in the MES-negative group (p = 0.002 and 0.02, respectively). Conclusion: In acute ischemic stroke, MES detected by TCD in the acute phase may produce small cortical and subcortical lesions found on DWI.

Copyright © 2007 S. Karger AG, Basel

  Author Contacts

Makoto Nakajima
Department of Medicine, Kumamoto Rosai Hospital
1670, Takehara-machi, Yatsushiro
Kumamoto 866-8533 (Japan)
Tel. +81 965 33 4151, Fax +81 965 32 4405, E-Mail rosainakazima@ybb.ne.jp

  Article Information

Received: July 19, 2006
Accepted: September 25, 2006
Published online: December 29, 2006
Number of Print Pages : 7
Number of Figures : 4, Number of Tables : 1, Number of References : 38