Clinical MRI Cutoff Points for Predicting Lacunar Stroke May Not Exist: Need for a Grading rather than a Dichotomizing System

Abstract

<i>Background:</i> Lacunar stroke has been defined as an infarct <15 mm in diameter in the presence of symptoms of lacunar syndromes. We investigated a new approach in predicting whether a deep infarct is caused by small arterial occlusion. <i>Methods:</i> A total of 319 consecutive patients with acute symptomatic infarcts within the striatocapsular territory underwent diffusion-weighted imaging (DWI) and diagnostic workups, including vascular and cardiological studies. Predictors for nonlacunar mechanisms were evaluated by logistic regression analysis, with the size of infarct (1-mm increase) and stroke syndrome (traditional vs. atypical lacunar syndrome vs. cortical syndrome) graded rather than dichotomized. <i>Results:</i> Amongst the 171 patients who did not meet the established criteria for lacunar stroke, that is, deep infarct of ≧15 mm or presenting symptoms of nontraditional lacunar syndrome, a documented etiology could not be determined in 97 (56.7%) patients. In contrast, amongst the 148 patients who met the criteria, 27 (18.2%) had nonlacunar mechanisms. Logistic regression analysis identified the variables that predicted nonlacunar stroke mechanisms with statistical significance as nontraditional lacunar syndromes (OR 2.19 for atypical lacunar syndrome, and OR 6.72 for cortical syndrome), infarct size on DWI (OR 1.05 per 1-mm increase), and unilateral multiple deep infarcts on DWI (OR 2.22, p < 0.05 in all cases). Receiver operating characteristic curves showed that discrimination power of the model derived from logistic regression analysis (grading system) was better than that of the previously established dichotomizing criterion in predicting nonlacunar mechanisms (p = 0.004). <i>Conclusions: </i>A clinically significant proportion of clinical MRI lacunae are associated with underlying nonlacunar mechanisms. Decisions regarding the extent of diagnostic procedures in patients with subcortical infarcts can be guided by the point value in terms of the stroke syndrome and infarct patterns, as well as the size of infarct.

Differential Risk Factors for Lacunar Stroke Depending on the MRI (White and Red) Subtypes of Microangiopathy

“…It has been previously reported that risk factors for cerebral atherosclerosis, such as hypercholesterolemia and diabetes, and myocardial infarction were more prevalent in patients with lacunar infarcts without leukoaraiosis than in those with leukoaraiosis [11]. However, the weakness of this study is that intracranial vessels were not evaluated, and it is possible that lacunar infarcts could be caused by branch atherosclerotic disease that may mimic SAO [22], [23], [24].…”

The infarct location predicts progressive motor deficits in patients with acute lacunar infarction in the lenticulostriate artery territory

“…Although the size criterion for lacunar infarction is 15 mm [16], this value was based on previous autopsy studies. Therefore, there is controversy with regard to the 15 mm criterion in acute MRI evaluation because it also shows acute cytotoxic or vasogenic edema [17][18][19]. Other recent studies on acute lacunar infarction selected 20 mm diameter as the cutoff point of lacunar infarction [2,7,20].…”

Multimodal MRI for Ischemic Stroke: From Acute Therapy to Preventive Strategies

“…The traditional criterion of an infarct size of <15 mm has recently been challenged 80,81. The infarct size in patients with symptomatic small arterial occlusions varied from 3.1 to 38.7 mm 81.…”

“…The infarct size in patients with symptomatic small arterial occlusions varied from 3.1 to 38.7 mm 81. A new stroke classification (Scandinavian Stroke Scale-Trial of Org 10172 in Acute Stroke Treatment)82 that used an infarct size criterion of 20 mm rather than 15 mm was designed for the diagnosis of lacunar stroke.…”