J. Oliveiva et al., Diffusion-weighted magnetic resonance imaging identifies the "clinically relevant" small-penetrator infarcts, ARCH NEUROL, 57(7), 2000, pp. 1009-1014
Background: Most patients initially seen with a clinical syndrome consisten
t with a small-penetrator infarct (SPI) also harbor multiple, chronic, hype
rintense, white matter lesions on conventional magentic resonance imaging t
ie, T2-weighted image [T2WI] and fluid-attenuation inversion recovery [FLAI
R] imaging). Diffusion-weighted imaging (DWI) can identify the clinically r
elevant "index infarction" in such circumstances, since it differentiates b
etween acute and chronic lesions.
Objective: To determine the clinical and radiological predictors associated
with misidentification of an SPI as acute using T2WI and FLAIR images in p
atients with an acute SPI seen on DWI.
Patients: Sixty-seven consecutive patients who had an SPI.
Methods: Two independent examiners, provided with brief clinical informatio
n, but blinded to DWI findings, sought a clinically appropriate lesion on T
2WI and FLAIR imaging in 67 consecutive patients found to have an SPI seen
on DWI.
Results: The index infarction based on evaluation of T2WI or FLAIR images w
as in a different location than the acute lesion as identified by DWI in 9
(13%) and 11 (16%) of 67 patients, respectively. Both T2WI and FLAIR imagin
g were rated normal in another 9% of the patients. Multivariate analysis sh
owed that small lesion size (<10 mm) was the only predictor of misidentifyi
ng the clinically appropriate lesion on conventional magnetic resonance ima
ging (P<.01).
Conclusions: T2-weighted imaging and FLAIR imaging fail to identify the cli
nically relevant SPI in almost one quarter of the patients found to have a
lesion on DWI. The characteristics of DWI make it well suited for the detec
tion of acute small infarcts. Diffusion-weighted imaging is necessary to co
nsistently define the clinical-anatomical relations in patients initially s
een with SPIs.