Advanced

AJNR - American Journal of Neuroradiology

Published ahead of print on November 11, 2008
doi: 10.3174/ajnr.A1355

This Article Free to Access Figures Only Full Text Full Text (PDF) All Versions of this Article: ajnr.A1355v1 30/2/338    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Nandigam, R.N.K. Articles by Dickerson, B.C. Search for Related Content PubMed PubMed Citation Articles by Nandigam, R.N.K. Articles by Dickerson, B.C.

American Journal of Neuroradiology 30:338-343, February 2009
© 2009 American Society of Neuroradiology

BRAIN

MR Imaging Detection of Cerebral Microbleeds: Effect of Susceptibility-Weighted Imaging, Section Thickness, and Field Strength

R.N.K. Nandigam^a, A. Viswanathan^a, P. Delgado^a, M.E. Skehan^a, E.E. Smith^a, J. Rosand^a, S.M. Greenberg^a and B.C. Dickerson^b,c

^a Hemorrhagic Stroke Research Program, Massachusetts General Hospital and Harvard Medical School, Boston, Mass
^b Alzheimer's Disease Research Center, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass
^c Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Mass

Please address correspondence to: Steven M. Greenberg, MD, PhD, Massachusetts General Hospital Stroke Research Center, 55 Fruit St, CPZ 175, Ste 300, Boston, MA 02114; e-mail: sgreenberg{at}partners.org

BACKGROUND AND PURPOSE: The emergence of cerebral microbleeds (CMB) as common MR imaging findings raises the question of how MR imaging parameters influence CMB detection. To evaluate the effects of modified gradient recalled-echo (GRE) MR imaging methods, we performed an analysis of sequence, section thickness, and field strength on CMB imaging properties and detection in subjects with cerebral amyloid angiopathy (CAA), a condition associated with microhemorrhage.

MATERIALS AND METHODS: Multiple MR images were obtained from subjects with probable CAA, with varying sequences (GRE versus susceptibility-weighted imaging [SWI]), section thicknesses (1.2–1.5 versus 5 mm), and magnetic field strengths (1.5T versus 3T). Individual CMB were manually identified and analyzed for contrast index (lesion intensity normalized to normal-appearing white matter signal intensity) and diameter. CMB counts were compared between 1.5T thick-section GRE and thin-section SWI for 3 subjects who underwent both protocols in the same scanning session.

RESULTS: With other parameters constant, use of SWI, thinner sections, and a higher field strength yielded medium-to-large gains in CMB contrast index (CI; Cohen d 0.71–1.87). SWI was also associated with small increases in CMB diameter (Cohen d <0.3). Conventional thick-section GRE identified only 33% of CMB (103 of 310) seen on thin-section SWI. Lesions prospectively identified on GRE had significantly greater CI and diameter measured on the GRE image than those not prospectively identified.

CONCLUSIONS: The examined alternatives to conventional GRE MR imaging yield substantially improved CMB contrast and sensitivity for detection. Future studies based on these techniques will most likely yield even higher prevalence estimates for CMB.

This article has been cited by other articles:

				Y.-A. Chung, J. Hyun O, J.-Y. Kim, K.-J. Kim, and K.-J. Ahn Hypoperfusion and Ischemia in Cerebral Amyloid Angiopathy Documented by 99mTc-ECD Brain Perfusion SPECT J. Nucl. Med., December 1, 2009; 50(12): 1969 - 1974. [Abstract] [Full Text] [PDF]

				S. M. Gregoire, U. J. Chaudhary, M. M. Brown, T. A. Yousry, C. Kallis, H. R. Jager, and D. J. Werring The Microbleed Anatomical Rating Scale (MARS): Reliability of a tool to map brain microbleeds Neurology, November 24, 2009; 73(21): 1759 - 1766. [Abstract] [Full Text] [PDF]