This Article Full Text Full Text (PDF) All Versions of this Article: 37/11/2713    most recent 01.STR.0000244827.36393.8fv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Saur, D. Articles by Röther, J. Search for Related Content PubMed PubMed Citation Articles by Saur, D. Articles by Röther, J. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Medline Plus Health Information MRI Scans Nuclear Scans Related Collections Acute Cerebral Infarction Computerized tomography and Magnetic Resonance Imaging PET and SPECT

(Stroke. 2006;37:2713.)
© 2006 American Heart Association, Inc.

Original Contributions

Iomazenil-Single-Photon Emission Computed Tomography Reveals Selective Neuronal Loss in Magnetic Resonance-Defined Mismatch Areas

Dorothee Saur, MD; Ralph Buchert, PhD; Rene Knab, MSc; Cornelius Weiller, MD Joachim Röther, MD

From the Department of Neurology (D.S., C.W.), University Medical Center Freiburg, Freiburg, Germany; the Departments of Nuclear Medicine (R.B.) and Neurology (R.K.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and the Department of Neurology (J.R.), Klinikum Minden, Academic Teaching Hospital, Hannover Medical School, Minden, Germany.

Correspondence to Dorothee Saur, MD, Department of Neurology, University Medical Center Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany. E-mail dorothee.saur{at}uniklinik-freiburg.de

Background and Purpose— The mismatch of hypoperfused tissue on perfusion imaging and ischemic tissue on diffusion-weighted imaging is used as a surrogate marker for thrombolytic therapy in the extended time window. Mismatch tissue may recover completely, progress toward infarction, or proceed toward incomplete infarction with selective loss of cortical neurons. We used [¹²³I]iomazenil–single-photon emission computed tomography (IMZ-SPECT) to characterize the neuronal integrity of reperfused "tissue at risk of infarction" that appeared morphologically intact on follow-up magnetic resonance imaging (MRI).

Methods— Twelve patients with acute stroke with striatocapsular (SC) infarctions were examined with multimodal MRI at days 0, 1, and 7; IMZ-SPECT was performed at days 5 to 15. The PI at day 0, fluid-attenuated inversion recovery (FLAIR) image at day 7, and IMZ-SPECT were coregistered and stereotactically normalized. The mismatch volume of interest (VOI) was defined as the initial PI lesion subtracted by the FLAIR lesion at day 7. An asymmetry ratio (AR) was computed by dividing the mean IMZ uptake of the mismatch VOI by the unaffected mirror VOI. The same AR was computed for signal intensity on FLAIR images at day 7. Three patients with cortical infarctions were included for calibration of the AR. In this group, the VOI consisted of the FLAIR lesion at day 7.

Results— All patients with SC infarctions had a large mismatch of initially hypoperfused (112±31 mL; mean±SD) and finally infarcted tissue (19±14 mL). Mean AR of cortical IMZ uptake was 0.85±0.01 in cortical infarctions and 0.95±0.03 in SC infarctions; thereby AR showed a continuous distribution from clearly reduced (0.89) to normal (1.01) in SC infarctions. Mean AR for FLAIR signal intensity was 1.84±0.14 for cortical infarctions and normal (1.01+0.03) for SC infarctions.

Conclusions— IMZ-SPECT detected a selective loss of cortical neurons in patients with SC infarctions in transient hypoperfused tissue, which was morphologically intact on MRI.

Key Words: cerebral ischemia • diffusion and perfusion imaging • incomplete infarction • iomazenil-SPECT • mismatch tissue

This article has been cited by other articles:

				J. V. Guadagno, P. S. Jones, F. I. Aigbirhio, D. Wang, T. D. Fryer, D. J. Day, N. Antoun, I. Nimmo-Smith, E. A. Warburton, and J. C. Baron Selective neuronal loss in rescued penumbra relates to initial hypoperfusion Brain, October 1, 2008; 131(10): 2666 - 2678. [Abstract] [Full Text] [PDF]

				C. Giffard, B. Landeau, N. Kerrouche, A. R. Young, L. Barre, and J.-C. Baron Decreased Chronic-Stage Cortical 11C-Flumazenil Binding After Focal Ischemia-Reperfusion in Baboons: A Marker of Selective Neuronal Loss? Stroke, March 1, 2008; 39(3): 991 - 999. [Abstract] [Full Text] [PDF]

				T. Tourdias, V. Dousset, I. Sibon, E. Pele, P. Menegon, J. Asselineau, C. Pachai, F. Rouanet, P. Robinson, G. Chene, et al. Magnetization Transfer Imaging Shows Tissue Abnormalities in the Reversible Penumbra Stroke, December 1, 2007; 38(12): 3165 - 3171. [Abstract] [Full Text] [PDF]

				W.-D. Heiss and A. G. Sorensen Advances in Imaging 2006 Stroke, February 1, 2007; 38(2): 238 - 240. [Full Text] [PDF]