Diffusion tensor imaging correlates with lesion volume in cerebral hemisphere infarctions (original) (raw)
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Journal of Magnetic Resonance Imaging, 2004
To investigate the development of ischemic brain lesions, as present in the acute stroke phase, by diffusion-weighted magnetic resonance imaging (DWI), and in the subacute and chronic phases until up to four months after stroke, in fluid-attenuated inversion recovery (FLAIR)- and T2-weighted (T2W) magnetic resonance (MR) images. Twelve consecutive patients with their first middle cerebral artery (MCA) infarction were included. Lesion volumes were assessed on T2W images recorded with a turbo spin echo (TSE) and on images recorded with the FLAIR sequence on average on day 8 and after about four months. They were compared with acute lesion volumes in perfusion and DWI images taken within 24 hours of stroke onset. On day 8, lesion volumes in images obtained with FLAIR exceeded the acute infarct volumes in DWI. The chronic lesion volumes were almost identical in T2W and FLAIR images but significantly reduced compared with the acute DWI lesions. The lesion volumes assessed on DWI images correlated highly with the lesions in the images obtained with TSE or FLAIR, as did the lesions in the images obtained with FLAIR and TSE. The secondary lesion shrinkage was accompanied by ventricular enlargement and perilesional sulcal widening, as most clearly visible in the images obtained with FLAIR. Our results show that the acute DWI lesions are highly predictive for the infarct lesion in the chronic stage after stroke despite a dynamic lesion evolution most evident in MR images obtained with FLAIR.
Stroke, 2006
Background and Purpose— Some infarcts have persistently hyperintense areas on diffusion-weighted MRI (DWI) even at 1 month after stroke, whereas others have become isointense to normal brain. We hypothesized that late DWI hyperintensity reflected different infarct evolution compared with areas that were isointense by 1 month. Methods— We recruited patients prospectively with ischemic stroke, performed DWI and perfusion-weighted MRI (PWI) on admission, at 5 days, 14 days, and 1 month after stroke, and assessed functional outcome at 3 months (Rankin Scale). Patient characteristics and DWI/PWI values were compared for patients with or without “still hyperintense” infarct areas on 1-month DWI. Results— Among 42 patients, 27 (64%) had “still hyperintense” infarct regions at 1 month, mostly in white matter. Patients with “still hyperintense” regions at 1 month had lower baseline apparent diffusion coefficient ratio (ADCr; mean±SD 0.76±0.12 versus 0.85±0.12; hyperintense versus isointense;...
Stroke, 2005
Background and Purpose— An acute mismatch on diffusion-weighted MRI (DWI) and perfusion-weighted MRI (PWI) may represent the “tissue-at-risk.” It is unclear which “semiquantitative” perfusion parameter most closely identifies final infarct volume. Methods— Acute stroke patients underwent DWI and PWI (dynamic-susceptibility contrast imaging) on admission (baseline), and T 2 -weighted imaging (T 2 WI) at 1 or 3 months after stroke. “Semiquantitative” mean transit time (MTT sq =first moment of concentration/time curve), cerebral blood volume (CBV sq =area under concentration/time curve), and cerebral blood flow (CBF sq =CBV sq /MTT sq ) were calculated. DWI and PWI lesions were measured at baseline and final infarct volume on T 2 WI acquired ≥1 month after stroke. Baseline DWI, CBF sq , and MTT sq lesion volumes were compared with final T 2 WI lesion volume. Results— Among 46 patients, baseline DWI and CBF sq lesions were not significantly different from final T 2 WI lesion volume, but...
Combined SPECT and Diffusion-Weighted MRI as a Predictor of Infarct Growth in Acute Ischemic Stroke
Journal of Nuclear Medicine, 2000
schemic stroke is a major cause of death and disability in the industrialized world. Despite much effort, development of efficient treatment has proven difficult. In clinical trials on treatment of acute ischemic stroke, CT has been used to exclude hemorrhage and extensive ischemic changes. Unfor tunately, CT is not very sensitive at detecting brain ischemia within the first few hours, which is when the treatment should be given. Although conventional MM is more sensitive than CT at detecting acute ischemia (1,2), it also often fails to detect hyperacute ischemia. In diffusion-weighted MRI, the imaging sequence is made sensitive to the molecular diffusion of water using strong magnetic field gradients (3,4). Ischemia leads to a decrease in water diffusion in brain tissue, which is seen as a high signal area on diffusion-weighted MM (5â€"8).The exact mechanism of decreased diffusion is unknown, but intracel lular swelling (cytotoxic edema) is thought to be 1 of the main contributors (5,6). In animal studies, this phenomenon is evident as early as 5 mm after the occlusion of the middle cerebral artery (9), which is clearly earlier than can be detected on conventional T2-weighted MR images (10). Diffusion-weighted MRI has also been shown to be more sensitive than conventional T2-weighted imaging at detect ing acute cerebral ischemia in humans (11â€"13). An experi mental study using a rat stroke model showed that a lesion with decreased diffusion can partially recover if the perfu sion is restored after 1 h from temporary occlusion of the middle cerebral artery (14). However, few observations of reversibility of diffusion-weighted MRI lesions in human strokes have been published (15). Although it is possible that the tissue with decreased diffusion may in some cases slightly overestimate the actual infarcted tissue also in human stroke, diffusion-weighted MM is at present the most accurate clinically available method to estimate the size of infarction in the acute phase of ischemia (16). Brain tissue with decreased perfusion can be detected by using perfusion imaging tracers and SPECT (17). Hypoper fused tissue detected by SPECT also contains irreversibly damaged, infarcted tissue. Tissue that is dysfunctional In acuteischemicstroke,the infarctedcore is surrounded by a zone of tissue that has decreased perfusion.Some of this tissue may be salvaged by prompt, effective treatment. Diffusion weighted MRI is sensitive in detecting the infarcted tissue, whereas SPECT also detects the hypopertused tissue around theinfarcted core.We studiedthepotential ofcombined diffusion weighted MRI and SPECT to predict infarct growth and clini cal outcome in patients not receiving thrombolytic treatment. Methods:Sixteenpatients withacutestrokewereexamined consecutively withdiffusion-weighted MRIand @â€oeTc-ethylcystein ate dimer (@â€oeTc-ECD) SPECT within 24 h of the onset of symptoms. Follow-updiffusion-weightedMRI was performed on correlated significantlywith the change in the NIHSS (r = 0.54; P < 0.05). Conclusion: A large hypoperfusionzone around the infarct core in the acute phase of ischemic stroke predicts the infarct growth during the first week, and this correlates signifi cantly with the change in the neurologic status of the patient. Combineddiffusion-weightedMRI and SPECT performedwithin 24hafter theonset ofsymptoms canbeuseful intheevaluation ofacutestroketo predict infarct growth.
Cureus, 2018
Diffusion-weighted magnetic resonance imaging (DW-MRI) represents a major advance in the early diagnosis of acute ischemic stroke. It can detect edema due to ischemia in the brain tissue. It not only establishes the presence and location of ischemic brain injury but also a relatively new concept is the determination of infarct patterns seen on diffusion imaging and its clinical correlation. Objective To determine the frequency of various infarct patterns and their relationship with functional outcome of the patient. Materials and methods A total of 108 patients with acute stroke were enrolled by purposive sampling. Magnetic resonance imaging (MRI) was obtained with departmental protocol and diffusion-weighted sequences. The clinical data was collected from medical records and functional outcome was assessed at the time of admission using Barthel Index (BI) which was dichotomized into poor and favorable outcomes. The radiological data was collected and three infarct patterns (cortica...
Establishing Final Infarct Volume: Stroke Lesion Evolution Past 30 Days Is Insignificant
Stroke, 2008
Background and Purpose-Lesion volume measured on MRI has been used as an objective surrogate marker for outcome in clinical trials. However, lesion volumes vary over time because of edema and tissue loss. This study aims to determine if lesion volumes measured at 30 and 90 days after ictus significantly differ. Methods-We performed a retrospective study of 18 patients who had acute (Ͻ24 hours) DWI and follow-up fluid-attenuated inversion recovery imaging at 5, 30, and 90 days. Two expert readers segmented lesions and the mean volumes of both reads were used in all statistical analyses. Results-Patient age was 65.8 (SD, 13.7) years and median NIHSS at baseline was 11.5. Inter-rater variability for lesion volume measurements was 3.7 (5.8) mL. Acute DWI volume was 19.3 (17.3) mL. Fluid-attenuated inversion recovery volumes for 5, 30, and 90 days were 34.3 (23.5), 18.6 (14.0), and 15.9 (13.8) mL, respectively. These volumes differed significantly (PϽ0.001). Linear regression revealed a strong correlation (rϭ0.96; PϽ0.001) between lesion volumes at 30 and 90 days with a slope that did not vary significantly from 1.0 (Pϭ0.448). Conclusions-Lesions continue to evolve between 5 and 90 days, but by 30 days lesion volume approaches final infarct volume. While clinical response is the most meaningful outcome measure, our findings suggest that lesion volumes measured at 30 days may provide a sufficient approximation for final infarct volume for use in early phase clinical trials.
AJNR. American journal of neuroradiology, 2005
Occlusion of major cerebral arteries is the primary source of tissue damage in ischemic stroke and the target of thrombolytic therapy. We hypothesized that large infarcts in more proximal vascular occlusions correspond with substantially increased ischemic lesions shown on initial apparent diffusion coefficient (ADC) maps. Initial ADC lesions in 120 patients with acute ischemic stroke were analyzed within 6 hours of stroke onset. Patients were categorized on the basis of vascular occlusion, as shown on MR angiography. Lesion volumes were determined by using manual delineation (ADC(man)) and a threshold method for ADC values (<550 x 10(-9) mm(2)/s(-1), ADC(<550)). Infarct volumes were analyzed by using T2-weighted (n = 109) or CT (n = 11) images obtained on days 5-8. Median lesion volumes for ADC(<550), ADC(man), and infarcts, respectively, were as follows: proximal internal carotid artery (ICA)/middle cerebral artery (MCA) occlusions, 10, 23, and 32 cm(3); carotid-T occlusi...
Stroke, 2014
D iffusion-weighted imaging measures the restriction of water movement associated with cytotoxic edema and has become the most sensitive imaging technique for detection of early cerebral ischemia. 1 Regions of restricted diffusion on diffusion-weighted imaging are associated with a decrease in Na-K-ATPase activity and energy failure, and in most cases represent irreversible infarction. Although several studies have demonstrated that apparent diffusion coefficient (ADC) values of <600×10 −6 mm 2 /s typically represent irreversible infarction 3 ; the ischemic changes remain rather ill-defined and the associated pathophysiology is not well understood.
Magnetic Resonance Imaging, 2015
Background-Non-infarct zone white matter wallerian degeneration is well-documented in large volume territorial infarctions. However to what extent these abnormalities exist in small volume infarction is not known, particularly since routine T2/FLAIR MR images show minimal changes in such cases. We therefore utilized DTI based quantitative 3D tractography for quantitative assessment of white matter integrity in chronic phase of small volume anterior circulation infarcts. Methods-Eleven chronic stroke subjects with small anterior circulation large vessel infarcts (≤10 cc volume of primary infarct) were compared with 8 age matched controls. These infarcts had negligible to mild gliosis and encephalomalacia in the primary infarct territory without obvious wallerian degeneration on conventional MRI. Quantitative Diffusion Tensor 3-D tractography was performed for CST, genu and splenium of corpus callosum. Tract based Trace and fractional anisotropy (FA) was compared with age matched controls. Results-On univariate analysis, Chronic stroke subjects had significant elevation in Trace measurement in genu of corpus callosum (GCC), ipsilesional and contralesional CST, (p<0.05),