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Neuroimaging methods. A , CTP maps and DWI lesions in a patient with a supratentorial lacunar infarct ( upper row ) and in a patient with a brain stem paramedian infarct ( lower row ). B , Representative examples of the quantification of NVT and TAR and the final DWI lesion in a patient with mismatch ( left ) and a patient with no mismatch ( right ). NVT indicates nonviable tissue; TAR, tissue at risk.
Source publication
The incidence and significance of perfusion abnormalities on brain imaging in patients with lacunar infarct are controversial. We studied the diagnostic yield of CTP and the type of perfusion abnormalities in patients presenting with a lacunar syndrome and in those with MR imaging-confirmed lacunar infarcts.
A cohort of 33 patients with lacunar syn...
Contexts in source publication
Context 1
... perfusion maps generated were the following: CBF, CBV, MTT, time to maximum of residue function maps, TTP, time to drain (TTD), and MIP. Ischemic lesions usually show decreased CBV and CBF and prolonged measures of time maps (Fig 2A). ...
Context 2
... ROI was then registered to perfusion maps generated by using MIStar (Apollo Medical Imaging Technology, Melbourne, Australia), a software that uses singular-value decomposition with a delay correction. 20 Within this ROI, we used a range of relative and absolute thresholds in the CBF and time maps to define infarct core or nonviable tissue and critically hypoperfused or tissue at risk, respectively (Fig 2B). "Mismatch" was defined as a greater extent of tissue at risk than nonviable tissue. ...
Context 3
... the evaluators assessed all perfusion maps together, the infarcts were best seen on TTD maps, which often showed the LIs as small red dots that were easy to distinguish from the back- ground (On-line Fig 2). Among the 16 cases with MR imaging- confirmed LI, CTP with negative findings was due to movement artifacts in 2 patients and to lesions located in the brain stem in 4 patients. ...
Similar publications
Background and Purpose—
We aim to identify factors associated with imaging-confirmed lacunar strokes and improve their rapid clinical identification early after symptom onset using data from the IST-3 (Third International Stroke Trial).
Methods—
We selected patients likely to have lacunar infarcts as those presenting with: Oxfordshire Community St...
Citations
... Anti-inflammatory drugs: colchicine in non-cardioembolic strokes (CONVINCE) [40], uric acid (URICO-ICTUS) [41], and canakinumab [42]. Perfusion studies show persistence of residual blood flow, in the territory of perforating arteries corresponding to RSSI [43,44]. Sequential imaging from row perfusion sequences may show retrograde flow, suggesting collateral circulation involvement in RSSI [28,45,46] Microscopic studies showed a dense capillary network, linking contiguous perforating arteries and few arteriolar anastomoses [47]. ...
... However, about 20% of patients with a lacunar stroke presented a transient ischemic attack in the previous hours or days [54], and patients presenting with a lacunar syndrome may recover without showing any ischemic lesion on brain imaging [55]. Perfusion studies on CT and MRI showed that small areas of hypoperfusion (but not a complete absence of it) are visible in some patients with a confirmed RSSI on follow-up imaging, including areas of potentially viable tissue (ischemic penumbra) [43,44], in contrast with the hypothesis of a complete flow obstruction, without compensation in a terminal arterial territory. The capsular warning syndrome was first described in patients with lacunar stroke involving the internal capsule presenting repeated, stereotyped episodes of motor lacunar syndrome or sensorimotor lacunar syndrome, within 24-72 h, with complete recovery between episodes, which involved two of three body parts (face, arm, or leg), or more, without cortical symptoms [56,57]. ...
... In addition, sensitivity and specificity are not comparable between studies, due to different population, selection criteria, RSSI prevalence, and study design. For example, some of the studies had extremely high specificity, probably due to pre-evaluation selection of patients or strict criteria to identify a perfusion deficit [163][164][165][166]. Nevertheless, the accuracy of non-contrast CT is highly improved by perfusion maps [43,163,164,166], which should be carefully evaluated for the presence of focal perfusion alterations, consistent with the clinical presentation. Table 5. ...
Lacunar infarcts represent one of the most frequent subtypes of ischemic strokes and may represent the first recognizable manifestation of a progressive disease of the small perforating arteries, capillaries, and venules of the brain, defined as cerebral small vessel disease. The pathophysiological mechanisms leading to a perforating artery occlusion are multiple and still not completely defined, due to spatial resolution issues in neuroimaging, sparsity of pathological studies, and lack of valid experimental models. Recent advances in the endovascular treatment of large vessel occlusion may have diverted attention from the management of patients with small vessel occlusions, often excluded from clinical trials of acute therapy and secondary prevention. However, patients with a lacunar stroke benefit from early diagnosis, reperfusion therapy, and secondary prevention measures. In addition, there are new developments in the knowledge of this entity that suggest potential benefits of thrombolysis in an extended time window in selected patients, as well as novel therapeutic approaches targeting different pathophysiological mechanisms involved in small vessel disease. This review offers a comprehensive update in lacunar stroke pathophysiology and clinical perspective for managing lacunar strokes, in light of the latest insights from imaging and translational studies.
... MR-based diffusion-weighted imaging (DWI) has also been utilized in the hyperacute stage of acute ischemic stroke management at select stroke centers. Some comparative studies have demonstrated superiority of MR-DWI protocols over CT perfusion maps for prediction of ischemic core [7], especially in cases of subcortical lesions [8][9][10], though its practical utility in the "real-world" setting remains relatively limited due to prolonged acquisition times compared to CT as well as 24/7 availability. In addition, MR perfusion protocols have been developed, which provide an alternative and arguably more reliable assessment of the penumbral tissue [7,11,12], especially in the later time windows, when compared to CT perfusion. ...
The field of acute stroke treatment has made tremendous progress in reducing the overall burden of disability. Understanding the pathophysiology of acute ischemic injury, neuroimaging to quantify the extent of penumbra and infarction, and acute stroke reperfusion therapies have together contributed to these advancements. In this review we highlight advancements in reperfusion therapies for acute ischemic stroke.
... Whole-brain computed tomography perfusion (WB-CTP) is a useful technique for screening patients with ischemic stroke for treatment with mechanical recanalization or intravenous thrombolysis within a narrow time window (5,6). Although WB-CTP has been applied to MMD to assess the feasibility of revascularization, the relationship between Suzuki stage, WB-CTP features, and clinical outcomes has not been reported (7). ...
... The observed changes in collateral circulation and hemodynamics following bypass surgery were related to postoperative complications. Mismatch in the cerebral cortex is thought to reflect a salvageable brain area after ischemic stroke (5). EC-IC bypass can have a marked effect on collateral circulation, inducing hemodynamic disturbances such as cerebral hyperperfusion syndome and postoperative watershed shift ischemia (15). ...
Objective: This study compared the clinical features and hemodynamic characteristics of patients in different Suzuki stages of ischemic moyamoya disease (iMMD) before and after treatment with extracranial-intracranial (EC-IC) bypass surgery combined with encephalo-duro-myo-synangiosis and whole-brain computed tomography perfusion (WB-CTP).
Methods: A total of 126 patients in different Suzuki stages (II, III, IV, and V) of iMMD who underwent bypass surgery from April 2013 to August 2020 were included in this retrospective study. MIStar automatic analysis of Whole brain CT perfusion imaging software (WB-CTP, Apollo Medical Imaging Technology, Melbourne, Australia) was used. The patients also underwent WB-CTP 1 day before and 1 week and 3 months after the surgery. The relationships between hemodynamic parameters in WB-CTP including delay time (DT) > 3 s, relative cerebral blood flow (rCBF) < 30%, mismatch and mismatch ratio, and clinical outcomes were evaluated for different Suzuki stages, with comparisons between early (II and III) and late (IV and V) stages.
Results: Combined bypass surgery was performed in 161 hemispheres of 126 patients with iMMD. Brain volume with DT > 3 s was decreased 1 week (51.5 ± 11.8 ml, P < 0.05) and 3 months (41.5 ± 10.7 ml, P < 0.05) after bypass compared to 1 day before bypass (104.7 ± 15.1 ml) in early-stage patients. In late-stage patients, the volume was increased 1 week after bypass compared to the preoperative value (154.3 ± 14.7 vs. 118.3 ± 19.1 ml, P < 0.05). Preoperative brain volume with rCBF < 30% was lower (9.8 ± 3.9 vs. 33.5 ± 11.0 ml) whereas preoperative mismatch ratio was higher (11.2 ± 2.8 vs. 3.6 ± 1.6) in early-stage as compared to late-stage patients (both P < 0.05). A higher modified Rankin scale score (0–1) was achieved by early-stage patients than by those in the late stage (93.8 vs. 80.4%, P < 0.05) at the 3-month follow-up.
Conclusions: WB-CTP is useful for assessing the effectiveness of combined bypass/revascularization in different Suzuki stages of iMMD. Patients in the early stage of disease with higher preoperative brain volume with DT > 3 s and mismatch ratio show greater improvements in hemodynamic parameters and fewer postoperative complications associated with hemodynamic disturbance following bypass than patients in the late stage. Preoperative mismatch ratio can serve as a marker for assessing the status of collateral circulation in different Suzuki stages of iMMD.
... Some of these patients (4/19, 21%) had a "benign oligemia" profile with Tmax prolongation > 4 s, but with either ongoing clinical symptoms or symptoms in partial resolution. This could be due to technical issues (lesion outside the selected slabs when CT perfusion was used), lacunar infarcts [31], spontaneous recanalization before The present study investigated the effect of advanced neuroimaging on IVT monotherapy. Patients who received endovascular reperfusion therapy were excluded from our analyses. ...
... Some of these patients (4/19, 21%) had a "benign oligemia" profile with Tmax prolongation > 4 s, but with either ongoing clinical symptoms or symptoms in partial resolution. This could be due to technical issues (lesion outside the selected slabs when CT perfusion was used), lacunar infarcts [31], spontaneous recanalization before imaging, or small lesions in the posterior circulation [32] where CT perfusion has lower sensitivity. However, it may also imply that among the "benign oligemia" regions, there might exist grey zones close to the Tmax 6 s threshold delay that correspond more to critical hypoperfused areas, and which, if left untreated, may lead to permanent neurological deficits. ...
Advanced neuroimaging is one of the most important means that we have in the attempt to overcome time constraints and expand the use of intravenous thrombolysis (IVT). We assessed whether, and how, the prior use of advanced neuroimaging (AN), and more specifically CT/MR perfusion post-processed with RAPID software, regardless of time from symptoms onset, affected the outcomes of acute ischemic stroke (AIS) patients who received IVT. Methods. We retrospectively evaluated consecutive AIS patients who received intravenous thrombolysis monotherapy (without endovascular reperfusion) during a six-year period. The study population was divided into two groups according to the neuroimaging protocol used prior to IVT administration in AIS patients (AN+ vs. AN−). Safety outcomes included any intracranial hemorrhage (ICH) and 3-month mortality. Effectiveness outcomes included door-to-needle time, neurological status (NIHSS-score) on discharge, and functional status at three months assessed by the modified Rankin Scale (mRS). Results. The rate of IVT monotherapy increased from ten patients per year (n = 29) in the AN− to fifteen patients per year (n = 47) in the AN+ group. Although the onset-to-treatment time was longer in the AN+ cohort, the two groups did not differ in door-to-needle time, discharge NIHSS-score, symptomatic ICH, any ICH, 3-month favorable functional outcome (mRS-scores of 0–1), 3-month functional independence (mRS-scores of 0–2), distribution of 3-month mRS-scores, or 3-month mortality. Conclusion. Our pilot observational study showed that the incorporation of advanced neuroimaging in the acute stroke chain pathway in AIS patients increases the yield of IVT administration without affecting the effectiveness and safety of the treatment.
... 21,23 Lacunar or small subcortical infarcts are usually not detected using CTP thresholds, but visual inspection of in particular mean transit time, time-to-peak, and time-to-drain maps has a high specificity but moderate sensitivity for detection of these infarcts. 16,24,25 Sensitivity for infratentorial lesions is, however, low. 25 ...
Perfusion imaging uses an intravascular tracer and serial imaging to quantify blood flow through the brain
parenchyma. In acute ischemic stroke, perfusion imaging
may increase diagnostic accuracy, aid treatment target identification, and provide prognostic information about functional outcome.1
Moreover, perfusion imaging can identify
patients who benefit from reperfusion beyond the conventional time window or in whom time of symptom onset is
unknown.2–4 Implementation of perfusion imaging in routine
acute stroke care allows individualized treatment of stroke
patients based on brain tissue status, rather than time-based
treatment on the group level.
In this review, we give an overview of computed tomography perfusion (CTP) and perfusion magnetic resonance imaging (MRP) in acute ischemic stroke and discuss technical
properties, clinical use, and pitfalls.
... [3] Interestingly, neurologists made proper use of brain computed tomography perfusion (CTP) in assessing acute stroke for the time window of mechanical thrombectomy or intravenous thrombolis. [4,5] However, quantitative analysis of revascularization in ischemic MMD is still not achieved. To gain quantitative analysis of treatment in MCAterminal territory in ischemic MMD, the present study analyzes the imaging data prior to and following the STA-MCA bypass combined with EDAMS via whole-brain CTP (WB-CTP). ...
... [5,11] Due to its higher sensitivity, concerning patients suffering ischemic stroke with mild symptoms or even unable to being clearly assessed in the first hours following stroke occurrence, WB-CTP could offer mismatch rate. [4] Some researchers proposed <30% thresholded CBF of normal hemisphere as the standard of infarct core in WB-CTP. [12] It is noted that WB-CTP has the advantage of confirming Table 2 Parameters of CTP concerning preoperative and postoperative outcomes in the 79 patients with ischemic moyamoya disease (n = 79). ...
... Han and Huang Medicine (2020) 99:7 Medicine minor ischemic stroke tissue (especially lacunar infarcts), but its sensitivity in supratentorial lesions higher than that of infratentorial one should be taken into consideration. [4] The brain CTP map increase the accuracy of detecting the small arteries occlusion including the distal branches or posterior circulation, which can learn more about the occurrence of intracranial vessels occlusion or stenosis and collateral level, and then perform the proper revascularization. [13] As to the present study, quantitative analysis of dynamic data was carried out by 2 different neuroradiologists blind to the patients and surgical revascularization, respectively. ...
Ischemic moyamoya disease (MMD) can be treated with the revascularization of superficial temporal artery to middle cerebral artery (STA-MCA) bypass combined with encephalo-duro-arterio-myo-synangiosis (EDAMS) effectively. The purpose of the present study was to quantify the revascularization of STA-MCA bypass combined with EDAMS via whole-brain computed tomography perfusion (WB-CTP).Seventy-nine consecutive patients with ischemic MMD who admitted to our hospital from August 2012 to October 2018 were carried out STA-MCA bypass combined with EDAMS. WB-CTP was performed at 24 hours prior to operation and 3 months following bypass with a follow-up WB-CTP, respectively. Both automatic analysis of WB-CTP (MIStar, Apollo Medical imaging Technology, Melbourne, Australia) for analyzing values of brain volume in delayed time (DT) >3 seconds and DT > 6 seconds, relative cerebral blood flow (γCBF) < 30% and its mismatch ratio or percentage and diffusion-weighted imaging of magnetic resonance imaging in the ischemic penumbra and the infarct core at the 2 time points were studied for verifying the effectiveness of the combined revascularization. Changes in DT values at MCA-terminal territory after revascularization had been investigated. The dynamic data were with reference to the individual cerebellar arteries.All patients with ischemic MMD underwent STA-MCA bypass combined with EDAMS successfully. The preoperative brain volume in DT > 3 seconds in MCA-terminal territory was significantly larger than that of postoperative one (P < .05) in the ischemic penumbra in ischemic MMD. The mismatch ratio in brain volume of 24 hours prior to revascularization in MCA-terminal territory was significantly lower than that of 3 months (P < .05) following combined revascularization. The percentage of mismatch in brain volume of 24 hours prior to revascularization vs that of 3 months and the value of γCBF < 30% were similar to the above mismatch ratio (P < .05). The ratio of postoperative brain volume in DT > 3 seconds vs DT > 6 seconds indicated no significant differences compared with that of preoperative one (P > .05).The WB-CTP can be regarded as a choice for quantifying the combined revascularization in the ischemic penumbra and the infarct core in ischemic MMD. As proposed methods, brain volume in DT > 3 seconds, the value of γCBF < 30% and mismatch ratio in brain volume in MCA-terminal territory should be paid more attention in assessing the validity of STA-MCA bypass combined with EDAMS in ischemic MMD.
... This makes it possible to demonstrate focal ischemia below the resolution visualized with CTA. This is particularly important in cases of non-large vessel occlusion [55][56][57][58]. ...
... Risk maps remove the complexities of interpreting multiple CTP parameter maps simultaneously, which can be challenging for non-experts. In addition to the prognostic information important to treatment selection, CTP is often diagnostic in the acute setting, particularly when a proximal LVO is not present [55][56][57][58]. ...
Purpose of Review
Multimodal CT imaging (non-contrast CT, NCCT; CT angiography, CTA; and CT Perfusion, CTP) is central to acute ischemic stroke diagnosis and treatment. We reviewed the purpose and interpretation of each component of multimodal CT, as well as the evidence for use in routine care.
Recent Findings
Acute stroke thrombolysis can be administered immediately following NCCT in acute ischemic stroke patients assessed within 4.5 h of symptom onset. Definitive identification of a large vessel occlusion (LVO) requires vascular imaging, which is easily achieved with CTA. This is critical, as the standard of care for LVO within 6 h of onset is now endovascular thrombectomy (EVT). CTA source images can also be used to estimate the efficacy of collateral flow in LVO patients. The final component (CTP) permits a more accurate assessment of the extent of the ischemic penumbra. Complete multimodal CT, including objective penumbral measurement with CTP, has been used to extend the EVT window to 24 h. There is also randomized controlled trial evidence for extension of the IV thrombolysis window to 9 h with multimodal CT. Although there have been attempts to assess for responders to reperfusion strategies beyond 6 h (“late window”) using collateral grades, the only evidence for treatment of this group of patients is based on selection using multimodal CT including CTP. The development of fully automated software providing quantitative ischemic penumbral and core volumes has facilitated the adoption of CTP and complete multimodal CT into routine clinical use.
Summary
Multimodal CT is a powerful imaging algorithm that is central to current ischemic stroke patient care.
... as previously described. 15 ...
BACKGROUND AND PURPOSE: Leukoaraiosis frequently coexists in patients with acute stroke. We studied whether leukoaraiosis could
confound the interpretation of CTP findings in patients treated with mechanical thrombectomy.
MATERIALS AND METHODS: We analyzed 236 patients with stroke treated with mechanical thrombectomy and studied with CTP, of
whom 127 (53.8%) achieved complete reperfusion. Periventricular white matter hyperintensities on MR imaging and hypodensities on
NCCT were assessed through the Fazekas score. CTP-predicted nonviable tissue was defined as relative CBF 30%, and final infarct volume was quantified in DWI. We estimated mean MTT, CBV, and CBF in the asymptomatic hemisphere. In patients achieving complete reperfusion, we assessed the accuracy of nonviable tissue to predict final infarct volume using the intraclass correlation coefficient across
periventricular hyperintensity/hypodensity Fazekas scores and variable relative CBF cutoffs.
RESULTS: MTT was longer (Spearman 0.279, P .001) and CBF was lower ( �0.263, P .001) as the periventricular hyperintensity
Fazekas score increased, while CBV was similar across groups ( �0.043, P .513). In the subgroup of patients achieving complete
reperfusion, nonviable tissue–final infarct volume reliability was excellent in patients with periventricular hyperintensity Fazekas score
grade 0 (intraclass correlation coefficient, 0.900; 95% CI, 0.805– 0.950), fair in patients with periventricular hyperintensity Fazekas scores 1 (intraclass correlation coefficient, 0.569; 95% CI, 0.327– 0.741) and 2 (intraclass correlation coefficient, 0.444; 95% CI, 0.165– 0.657), and poor in patients with periventricular hyperintensity Fazekas score 3 (intraclass correlation coefficient, 0.310; 95% CI, �0.359 – 0.769). The most accurate cutoffs were relative CBF 30% for periventricular hyperintensity Fazekas score grades 0 and 1, relative CBF 25% for periventricular hyperintensity Fazekas score 2, and relative CBF 20% for periventricular hyperintensity Fazekas score 3. The reliability analysis according to periventricular hypodensity Fazekas score grades on NCCT was similar to that in follow-up MR imaging.
CONCLUSIONS: In patients with stroke, the presence of leukoaraiosis confounds the interpretation of CTP despite proper adjustment of
CBF thresholds.
... RSSIs can be observed as hypoperfused areas on computed tomography perfusion (CTP) maps despite their small volume. [7][8][9][10][11][12] The diagnostic yield of CTP in detecting RSSIs is conditioned by a high rate of false negative scans that have been explained by limited coverage, movements during image acquisition, bone artifacts, and low signal-to-noise ratio of the perfusion maps. 13 However, some RSSIs show no perfusion defects despite complete brain coverage and good quality of image acquisition, 7 raising the possibility that the lack of focal hypoperfusion on CTP maps could also be indicative of restored perfusion rather than a limitation of the technique. ...
... [7][8][9][10][11][12] The diagnostic yield of CTP in detecting RSSIs is conditioned by a high rate of false negative scans that have been explained by limited coverage, movements during image acquisition, bone artifacts, and low signal-to-noise ratio of the perfusion maps. 13 However, some RSSIs show no perfusion defects despite complete brain coverage and good quality of image acquisition, 7 raising the possibility that the lack of focal hypoperfusion on CTP maps could also be indicative of restored perfusion rather than a limitation of the technique. Indeed, areas of ischemic penumbra have been described in patients with subcortical infarcts, 7,14 while patients with lacunar infarcts and fluctuating symptoms may also exhibit fleeting perfusion abnormalities. ...
Hypoperfusion is the typical perfusion pattern associated with recent small subcortical infarcts of the brain, but other perfusion patterns may be present in patients with these infarcts. Using CT perfusion, we studied 67 consecutive patients who had a small subcortical infarct at a follow-up MRI study to investigate the correlation between the perfusion pattern and the clinical and radiological course. On CT perfusion map analysis, 51 patients (76%) had focal hypoperfusion, 4 patients (6%) had hyperperfusion and the remaining 12 patients (18%) showed no abnormalities. On dynamic sequential imaging analysis obtained from the source perfusion images, 32 patients (48%) had a sustained hypoperfusion pattern, 11 patients (16%) had a reperfusion pattern, and 18 patients (27%) had a delayed compensation pattern. Systolic blood pressure was higher in patients with sustained hypoperfusion although the perfusion pattern was independent of the final volume of infarction. These results reinforce the notion that mechanisms other than hypoperfusion are at play in patients with small subcortical infarcts including the intervention of compensatory sources of blood flow. The ultimate clinical significance of these perfusion patterns remains to be determined in larger series of patients assessed longitudinally.
... This confusion between lacunar mechanism and "lacunar phenotype" may have confounded earlier work on this subject (10). More recently, authors have described various patterns of perfusion deficits related to these small subcortical infarcts (11)(12)(13)(14)(15)(16). These patterns are categorized as mismatch, matched, and inverse mismatch. ...
... Our finding of a high frequency of perfusion deficits, in small subcortical infarcts is not surprising since the presence of ischemia should be associated with perfusion deficit (11)(12)(13)(14)(15)(16). Several patterns of perfusion deficit with subcortical infarcts have been described including "inverse mismatch. ...
... Consequently, in that study, it was only able to provide an estimate of occlusive disease of the MCA up to the M2 segment, and hence, it is unsurprising that angiographic abnormalities were not found (10). Other investigators have mentioned conducting angiographic studies (14) or the use of multimodality MR imaging (12,13) or CT imaging (15), but data on vessel occlusion were not presented. ...
Background: Lacunar infarcts have been characterized as small subcortical infarcts, resulting from in situ microatheroma or lipohyalinosis in small vessels. Based on this hypothesis, such infarcts should not be associated with large areas of perfusion deficits extending beyond subcortical regions to involve cortical regions. By contrast, selected small subcortical infarcts, as defined by MR imaging in the subacute or chronic stage, may initially have large perfusion deficits or related large vessel occlusions. These infarcts with ‘lacunar’ phenotype may also be caused by disease in the parent vessel and may have very different stroke mechanisms from small vessel disease. Our aim was to describe differences in imaging characteristics between patients with small subcortical infarction with ‘lacunar phenotype’ from those with lacunar mechanism. Methods: Patients undergoing acute CT Perfusion/angiography (CTP/CTA) within 6 hours of symptom onset and follow-up magnetic resonance imaging (MRI) for ischaemic stroke were included (2009-2013). A lacunar infarct was defined as a single subcortical infarct (SSI) ≤20 mm on follow-up MRI. Presence of perfusion deficits, vessel occlusion and infarct dimensions were compared between lacunar infarcts and other topographical infarct types. Results: Overall, 182 patients (mean age 66.4±15.3 years, 66% male) were included. SSI occurred in 31 (17%) patients. Of these, 12 (39%) patients had a perfusion deficit compared with those with any cortical infarction (120/142, 67%), and the smallest SSI with a perfusion deficit had a diameter of
