Diffusion- and Perfusion-Weighted Imaging in Acute Lacunar Infarction: Is There a Mismatch?

Abstract

PurposeCharacterization of lacunar infarction (LI) by use of multimodal MRI including diffusion- and perfusion-weighted imaging (DWI, PWI) is difficult because of the small lesion size. Only a few studies evaluated PWI in LI and the results are inconsistent.MethodsIn 16 LI patients who underwent initial MRI within 6 hours after symptom onset and follow-up MRI within 1 week demographics, clinical presentation, and MRI findings were analyzed with special emphasis on DWI and PWI findings. Time to peak maps were classified as showing a normal perfusion pattern or areas of hypoperfusion which were further categorized in mismatch (PWI>DWI), inverse mismatch (PWI<DWI), and match (PWI=DWI). Quantitative perfusion maps were generated and analyzed by use of Signal Processing in NMR-Software (SPIN).ResultsOf the 16 patients (mean age 65.5±12.9 years), 14 (87.5%) were male. Clinical symptoms comprised dysarthria (50%), hemiparesis (81.3%), and hemihypaesthesia (18.8%). Intravenous thrombolysis was performed in 7 (43.8%) patients. Clinical improvement was observed in 12 patients (75 %), while 2 (12.5%) patients showed a deterioration and another 2 (12.5%) a stable course. Acute ischemic lesions (mean volume of 0.46±0.29 cm3) were located in the thalamus (n=8, 50%), internal capsule (n=4, 25%), corona Radiata (n=3, 18.8%) and the mesencephalon (n=1, 6.3%). Circumscribed hypoperfusion (mean volume 0.61±0.48 cm3) was evident in 10 (62.5%) patients. Of these, 3 patients demonstrated a match, 4 an inverse mismatch, and 3 a mismatch between DWI and PWI lesion. Mean CBF and CBV ratios were 0.65±0.28 and 0.84±0.41 respectively. Growth of DWI lesions was observed in 7 (43.8%) and reversal of DWI lesions in 3 (18.8%) patients.ConclusionsMRI allows identification of different DWI and PWI patterns in LI, including growth and reversal of ischemic lesions. Consequently, it may serve for a better characterization of this stroke subtype and support treatment decisions in daily clinical practice.

Perfusion Deficits and Mismatch in Patients with Acute Lacunar Infarcts Studied with Whole-Brain CT Perfusion

“…The results of this study by using whole-brain-coverage CTP are very similar to those of a recent study by using perfusion MR imaging in patients with LI that reported perfusion deficits in 10/16 patients. 14 The sensitivity of whole-brain CTP was much higher than that of NCCT for acute stroke and in particular for LI, and the greater sensitivity of CTP in this study may reflect both whole-brain coverage of perfusion maps and the refinement of current parameters to assess perfusion maps. Studies with negative findings were due to very small lesions that were poorly differentiated from the background, especially in the brain stem; and in a few cases, they were due to poor image quality from movement artifacts.…”

“…6 Conflicting results have been reported regarding the presence of perfusion deficits in patients with LI, [7][8][9][10][11] with sensitivities varying from 0% to 68% in studies using MR imaging [12][13][14] and from 17% to 47% with CTP. 15,16 In fact, LI is considered one of the causes of false-negative CTP findings.…”

Neuroimaging Markers for Early Neurologic Deterioration in Single Small Subcortical Infarction

“…Previous studies have usually been limited to retrospective data collection and smaller sample sizes. 5,8,[10][11][12]14,16,[27][28][29][30] From our research experience in collecting the acute complications of acute stroke cases, 21 we established detailed definitions and protocols about END and successfully implemented these into our daily clinical practice. When a nursing staff member or duty resident detected END, the information was readily spread via a texting service to the on-duty doctors and attending physicians.…”

“…31 However, evidence has accumulated indicating the potential contribution from atherosclerotic processes including the formation of a microatheroma or hemodynamic compromise of an infarction. 14,32 Owing to the two distinct entities of lacunar infarction, 33 SSSIs from atherosclerotic pathologies have been suggested to be larger in size and located in the proximal basal ganglia. 1,34 Our results, in view of the current theory, propose that the biological characteristics of arterial occlusive lesions and the localized parenchymal responses after the occlusion of arterioles would vary according to the nature of the occlusion.…”

“…4,[8][9][10][11][12][13][14][15][16] However, these studies were conflicting and mostly conducted in a retrospective manner. A potential breakthrough about this issue may come from a detailed analysis of imaging findings that implicate 2 different pathological processes that contribute to the occurrence of SSSIs.…”