Are multiple acute small subcortical infarctions caused by embolic mechanisms?

OBJECTIVE: To seek evidence of potential embolic sources or other stroke mechanisms in patients who, on chance observation, had several apparently recent small subcortical infarcts on diffusion weighted magnetic resonance imaging (DWI). METHODS: Patients presenting with stroke and multiple hyperintense subcortical infarcts visible on DWI were identified prospectively. Detailed clinical and radiological assessments were done independently and blinded to each other. RESULTS: Of 10 patients with multiple hyperintense subcortical infarcts on DWI, a definite embolic source was identified in only one. Most patients were hypertensive and smoked. The DWI appearance suggested that the subcortical lesions had occurred within several weeks rather than at exactly the same time. Most patients also had significant white matter hyperintensities and four had microhaemorrhages. CONCLUSIONS: Embolic sources were not identified in most patients but they did have systemic vascular risk factors and brain imaging features of "small vessel disease." A more generalised intrinsic process affecting many small cerebral vessels contemporaneously could explain multiple acute small subcortical infarcts. White matter hyperintensities, microhaemorrhages, and multiple small subcortical infarcts may share a common pathophysiological mechanism such as a diffuse cerebral microvascular abnormality which requires further exploration.     

合并恶性肿瘤的脑梗死的临床特点及影响预后的相关因素分析

目的 分析合并恶性肿瘤的脑梗死患者的临床特征及影像学特点,探讨影响患者预后的相关因素.方法 回顾性分析2015年10月-2020年6月于中国医科大学附属第一医院神经内科收治的合并恶性肿瘤的脑梗死患者的临床资料,根据患者出院90 d时mRS评分将其分为预后良好组(mRS 0～2分)和预后不良组(mRS>2分).采用多因素...     

Clinical and radiological correlates of reduced cerebral blood flow measured using magnetic resonance imaging

BACKGROUND: Methods for determining cerebral blood flow (CBF) using bolus-tracking magnetic resonance imaging (MRI) have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional CBF in animal stroke models. OBJECTIVES: To determine the clinical and radiological features of patients with severe reductions in CBF on MRI and to analyze the relationship between reduced CBF and ADCs in acute ischemic stroke. DESIGN: Case series. SETTING: Referral center. METHODS: We studied 17 patients with nonlacunar acute ischemic stroke in whom perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) were performed within 7 hours of symptom onset. A PWI-DWI mismatch of more than 20% was required. We compared patients with ischemic lesions that had CBF of less than 50% relative to the contralateral hemisphere with patients with lesions that had relative CBF greater than 50%. Characteristics analyzed included age, time to MRI, baseline National Institutes of Health Stroke Scale score, mean ADC, DWI and PWI lesion volumes, and 1-month Barthel Index score. RESULTS: Patients with low CBF (n = 5) had lower ADC values (median, 430 x 10 (-6) mm(2)/s vs. 506 x 10 (-6) mm(2)/s; P =.04), larger DWI volumes (median, 41.8 cm(3) vs. 14.5 cm(3); P =.001) and larger PWI lesions as defined by the mean transit time volume (median, 194.6 cm(3) vs. 69.3 cm(3); P =.01), and more severe baseline National Institutes of Health Stroke Scale scores (median, 15 vs. 9; P =.02). CONCLUSION: Ischemic lesions with severe CBF reductions, measured using bolus-tracking MRI, are associated with lower mean ADCs, larger DWI and PWI volumes, and higher National Institutes of Health Stroke Scale scores.     

Spectrum of the posterior inferior cerebellar artery territory infarcts. Clinical-diffusion-weighted imaging correlates

BACKGROUND AND PURPOSE: The clinical, etiological and stroke mechanisms are defined well before but the detailed clinical and etiologic mechanisms regarding to all clinical spectrum of posterior inferior cerebellar artery (PICA) infarcts were not systematically studied by diffusion-weighted imaging (DWI). METHODS: Seventy-four patients with PICA territory ischemic lesion proved by DWI with decreased apparent diffusion coefficient and FLAIR (fluid attenuation inversion recovery) included in our Registry, corresponding to 2% of 3,650 patients with ischemic stroke, were studied. The presence of steno-occlusive lesions in the posterior circulation were sought by magnetic resonance angiography, and reviewed with a three-dimensional rotating cineangiographic method. RESULTS: We found six subgroups of PICA territory infarcts according clinico-topographical relationship: (1) 9 patients with lesion in the territory lateral branch of PICA; (2) 23 patients with an infarct in the territory of medial branch of PICA; (3) 9 patients with a lesion involving both medial and lateral branches of the PICA; (4) 9 patients with cortical infarcts at the boundary zones either between medial and lateral branches of the PICA or between PICA and m/l superior cerebellar artery (SCA); (5) 10 patients with a lesion at the deep boundary zones either between medial and lateral PICA, or between PICA and medial/lateral SCA; (6)14 patients with concomitant multiple lesions in the PICA and in other vertebrobasilar artery territories. The main cause of PICA infarcts was extracranial large-artery disease in 30 patients (41%) patients, cardioembolism and in situ branch disease in 15 patients (20%) each. CONCLUSIONS: Multiple PICA territory lesions on DWI were not uncommon and could be caused by multiple emboli originating from break-up of atherosclerotic plaque in the subclavian/innominate-vertebral arterial system. DWI findings of single or multiple small lesions could account for some cases with transient and subtle cerebellar symptoms which have been considered before as 'vertebrobasilar insufficiency' without morphologic lesion. Different clinical-DWI correlations allow us to determine better definition of the topographical and etiological spectrum of acute PICA territory lesions, which was previously defined by pathological and conventional MRI studies.     

Scattered brain infarct pattern on diffusion-weighted magnetic resonance imaging in patients with acute ischemic stroke

BACKGROUND AND PURPOSE: Infarct patterns on brain imaging contribute to the etiologic classification of ischemic stroke. However, the association of specific subtypes of infarcts and etiologic mechanisms is often weak, and acute lesions are frequently missed on initial computed tomography (CT). Diffusion-weighted imaging (DWI) is superior in visualizing acute ischemic lesions as compared to CT and conventional magnetic resonance imaging (MRI). In our prospective study, we addressed the question whether a distinct pattern of infarction on DWI is associated with infarct etiology and clinical outcome. METHODS: Sixty-two patients with clinical signs of acute ischemic stroke and negative acute CT upon admission underwent DWI within 10 days after the ictus. Neurological status was documented using the NIH stroke scale. A scattered lesion pattern was defined by at least 2 separate hyperintense DWI lesions within the territory of one of the major cerebral arteries. Ischemic lesions were defined as acute if the region was demarcated strongly hyperintense in all DW images, and if the apparent diffusion coefficient was below normal. RESULTS: In 32 patients, DWI revealed a scattered lesion pattern, while in 30 patients a single acute lesion was detected. In patients with scattered lesions, potential arterial or cardiac embolic sources were detected in 26 patients (81.3%), as compared to 5 patients (16.6%) in the group with single lesions (chi(2) test, p < 0.0001). The neurological status of patients with scattered lesions improved significantly more than among patients with single lesions (Mann-Whitney test, p < 0.0003). CONCLUSION: A scattered lesion pattern on DWI in patients with acute brain infarction and negative initial CT scan is associated with an embolic etiology and may indicate a favorable clinical outcome.     

Lesion patterns and mechanism of ischemia in internal carotid artery disease: a diffusion-weighted imaging study

CONTEXT: Although embolism and low-flow phenomenon are the 2 main mechanisms of stroke in internal carotid artery (ICA) occlusive disease, the mechanism of border-zone infarction remains controversial. Diffusion-weighted imaging (DWI) can more easily detect small or multiple ischemic lesions than conventional imaging. OBJECTIVES: To investigate the ischemic lesion patterns on DWI and to discuss the mechanisms of stroke in ICA disease. DESIGN: Case series. SETTING: A tertiary referral center. PATIENTS: We enrolled 35 consecutive patients who had an acute ischemic stroke and (> or = 70%) stenosis or an occlusion of the extracranial ICA confirmed by cerebral angiography and an acute relevant stroke lesion on DWI within 1 week of onset, but without cardiac sources of embolism and tandem intracranial arterial disease. MAIN OUTCOME MEASURES: The lesion pattern on DWI was categorized as territorial or border zone. Multiple ischemic lesions were defined as noncontiguous lesions on DWI in more than 1 vascular territory. RESULTS: There were 3 distinctive stroke lesion patterns. (1) A territorial lesion without a border-zone lesion was found in 21 patients: superficial and superficial territorial in 9, superficial and deep territorial in 7, and single in 5. (2) A border-zone lesion with or without a territorial lesion was found in 10 patients: border zone and territorial in 9 and border zone alone in 1. (3) Bilateral hemispheric lesions were found in 4 patients. Multiple ischemic lesions were found in 29 (82.9%) of the 35 patients. No patient had episodes of hemodynamic compromise. CONCLUSIONS: An acute ischemic lesion in ICA occlusive disease is mainly multiple. Border-zone infarction was mostly associated with territorial infarction. These results support the fact that embolism is the predominant stroke mechanism in ICA occlusive disease.     

以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤12例报告

目的研究以急性多发脑梗死为首发表现的隐匿性躯体恶性肿瘤患者的临床表现、实验室检查、影像学、微栓子监测检查特点,探讨其可能的发病机制。方法纳入以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤患者12例,收集其临床资料,分析其实验室血液学、头颅MRI、微栓子监测结果及其治疗和预后。结果所有患者均以局灶性神经功能缺损为主要表现,包括偏瘫、失语、偏身感觉障碍、构音障碍、眩晕、肢体抽搐等。头颅DWI示急性多发脑梗死,病灶播散性分布,不符合单支动脉供血区,同时累及双侧前循环或前后循环。11例行D-dimer检查者8例升高。7例行微栓子监测有5例阳性。隐匿性躯体恶性肿瘤包括:肺癌5例,胰腺癌3例,胃癌、结肠癌、子宫内膜癌、转移性低分化粘液腺癌原发肿瘤部位不明各1例;诊断时就已有远处转移者10例。病程中缺血性卒中复发者7例,急性心肌梗死4例,住院期间死亡3例,预后差。结论对于不符合单支动脉供血区的多发急性脑梗死,需要考虑可能合并隐匿性躯体恶性肿瘤,凝血功能筛查高凝状态和微栓子阳性可能是诊断提示线索。     

The differences of clinical parameters between small multiple ischemic lesions and single lesion detected by diffusion-weighted MRI

OBJECTIVES: The cause of small infarction is mainly considered to be intracranial small-vessel disease. However, it is difficult to explain the mechanism of multiple, acute infarctions by small-vessel disease. We examined the differences of clinical parameters between patients with multiple small lesions and single lesion detected by Diffusion-weighted MRI (DWI). MATERIAL AND METHODS: We reviewed the clinical records of 86 consecutive stroke patients with lacunar size ischemic lesions on DWI during the acute stage (within 72 h of onset). The subjects were 55 males and 31 females (mean age 72.4 +/- 9.9 years). Small multiple acute ischemic lesions were defined using the following criteria 1): the lesions were detectable by DWI 2), the diameter of each lesion on DWI was less than 1.5 cm, and 3) more than one vascular territory was involved. Included in the analysis were age, sex, lipoprotein (a) levels, hematocrit, atrial fibrillation (Af), stenosis of middle cerebral artery (MCA), internal carotid artery (ICA) or basilar artery stenosis detected by magnetic resonance angiography (MRA), National Institute of Health Stroke Scale (NIHSS) at admission, and a history of hypertension, diabetes mellitus, hyperlipidemia, and smoking. RESULTS: Twenty-one (24.4%) out of 86 patients with small acute infarctions had multiple acute ischemic lesions. Multiple logistic regression analysis showed that Af and stenosis of ICA or basilar artery were significantly more prevalent in patients with multiple lesions than single lesions. CONCLUSION: Multiple, small lesions visible in DWI are likely to be caused by emboli from heart or atheroma of the large vessels than single small lesion.     

Multiple acute stroke syndrome: marker of embolic disease?

OBJECTIVE: To determine the frequency and etiologic significance of multiple acute ischemic lesions in stroke. BACKGROUND: Although patients may have more than one stroke during the course of their lives, acute ischemic stroke is usually thought of as a single event. Using diffusion-weighted imaging (DWI), an MRI technique that detects ischemic injury within minutes after onset, we have often observed multiple acute ischemic lesions. Methods: The MRI scans of 59 consecutively studied patients were reviewed to determine the frequency and etiologic significance of multiple acute ischemic lesions on DWI. RESULTS: Multiple acute ischemic lesions were present in 10 (17%) of 59 patients. The lesions usually occurred within one major circulation (anterior or posterior), but in two patients (3%), lesions occurred in both cerebral hemispheres or in the anterior and the posterior circulations. The lesions often were small and resulted from presumed multiple emboli or the break-up of an embolus. Two patients had internal carotid artery occlusive disease and four had a cardiac or aortic source. In the other four patients the source was not determined. Lesions larger than 1 cm in diameter progressed to infarction, but some smaller lesions were not seen on follow-up T2-weighted imaging. CONCLUSIONS: Multiple acute stroke lesions on DWI are common and could be caused by multiple emboli or the breakup of an embolus. In some cases it might become possible to make early inferences concerning the stroke mechanism that could be of use for immediately directing the clinical work-up and treatment of the patient.     

Early ischemic lesion recurrence within a week after acute ischemic stroke

Previous observations suggested that multiple ischemic lesions on diffusion-weighted imaging (DWI) are common in acute stroke patients. We hypothesized that a source of these multiple lesions was the recurrence of ischemic lesions within a week after a clinically symptomatic stroke. We analyzed 99 acute ischemic stroke patients scanned within 6 hours of onset and at subsequent times within the first week. Ischemic lesion recurrence was defined as any new lesion separate from the index lesion. Recurrent lesions occurring outside initial perfusion deficit were termed 'distant lesion recurrence'. We estimated the hazard ratio (HR) of recurrence associated with clinical and imaging characteristics using log-rank test. Any lesion recurrence was found in 34%, with distant lesion recurrence in 15%, while clinical recurrence was evident in 2%. Initial multiple DWI lesions were associated with any lesion recurrence (HR, 2.83; 95% confidence interval [CI], 1.65-10.29; p = 0.002) and with distant lesion recurrence (HR, 5.99; 95% CI, 4.05-64.07; p < 0.0001). Large-artery atherosclerosis was the most frequent stroke subtype associated with any lesion recurrence (p = 0.026). These results may indicate a prolonged state of increased ischemic risk over the first week and suggest DWI as a possible surrogate measure for recurrent stroke.     

Patterns of diffusion‐weighted magnetic resonance imaging associated with etiology improve the accuracy of prognosis after transient ischaemic attack

Objective: Diffusion‐weighted magnetic resonance imaging (DWI) is a sensitive diagnostic tool for detecting acute ischaemic lesions in patients with transient ischaemic attacks (TIAs). The additional predictive value of DWI lesion patterns is not well known. Methods: Two hundred and fifty‐four consecutive patients with TIA underwent DWI within 7 days of symptom onset. The presence and pattern of acute ischaemic lesions were related to clinical features, etiology, and stroke recurrence at seven‐ and 90‐day follow‐up. Results: Diffusion‐weighted images abnormalities were identified in 117 (46.1%) patients. The distribution of DWI lesions was cortical, 31; subcortical, 32; scattered lesions in one arterial territory (SPOT) 42; and in multiple areas, 12. SPOT were significantly associated with motor weakness, large‐artery atherosclerosis (LAA), and the cardioembolic subtype of TIA. Single cortical lesions were also associated with cardioembolism, whereas subcortical acute lesions were associated with recurrent episodes, dysarthria, and motor weakness. During follow‐up, seven patients had a stroke within 7 days (2.8%, 95% CI 2.9–6.4%), and 12 had a stroke within 3 months (4.7%%, 95% CI 2.9–6.4%). In the Cox logistic regression model, the combination of LAA and positive DWI remained as independent predictors of stroke recurrence at 90‐day follow‐up (HR 5.78, 95 CI 1.74–19.21, P = 0.004). Conclusion: According to our results, MRI, including DWI, should be considered a preferred diagnostic test when investigating patients with potential TIAs. The combination of neuroimaging and vascular information could improve prognostic accuracy in patients with TIA.     

Yield of diffusion-weighted MRI for detection of potentially relevant findings in stroke patients

OBJECTIVE: To determine whether diffusion-weighted imaging (DWI) could identify potentially clinically relevant findings in patients presenting more than 6 hours after stroke onset when compared with conventional MRI. METHODS: MRI with both conventional (T2 and proton density images) and echoplanar imaging (DWI and apparent diffusion coefficient maps) was performed 6 to 48 hours after symptom onset (mean, 27 hours) in 40 consecutive patients with acute stroke. All acute lesions were identified first on conventional images, then on DWI, by a neuroradiologist who was provided with the suspected lesion location, based on a neurologist's examination before imaging. Abnormalities were rated as potentially clinically relevant if they were detected only on DWI and 1) confirmed the acute symptomatic lesion to be in a different vascular territory than suspected clinically, 2) revealed multiple lesions in different vascular territories suggestive of a proximal source of embolism, or 3) clarified that a lesion, thought to be acute on conventional imaging, was not acute. RESULTS: The initial clinical impression of lesion localization was incorrect in 12 patients (30%). Clinically significant findings were detected by DWI alone in 19 patients (48%). DWI demonstrated the symptomatic lesion in a different vascular territory than suspected clinically or by conventional MRI in 7 patients (18%) and showed acute lesions in multiple vascular distributions in 5 patients (13%). In 8 patients (20%), DWI clarified that lesions thought to be acute on conventional MRI were actually old. CONCLUSION: In patients imaged 6 to 48 hours after stroke onset, DWI frequently provided potentially clinically relevant findings that were not apparent on conventional MRI.     

Diffusion-weighted imaging identifies a subset of lacunar infarction associated with embolic source

BACKGROUND AND PURPOSE: Small infarcts in the territory of penetrator arteries were described as causing a number of distinct clinical syndromes. The vascular pathophysiology underlying such infarcts is difficult to ascertain without careful pathological study. However, the occurrence of multiple, small infarcts, linked closely in time but dispersed widely in the brain, raises the possibility of an embolic mechanism. The current study determines the frequency and clinical characteristics of patients with well-defined lacunar syndromes and the diffusion-weighted imaging (DWI) evidence of multiple acute lesions. METHODS: Sixty-two consecutive patients who presented to the emergency room with a clinically well-defined lacunar syndrome were studied by DWI within the first 3 days of admission. RESULTS: DWI showed multiple regions of increased signal intensity in 10 patients (16%). A hemispheric or brain stem lesion in a penetrator territory that accounted for the clinical syndrome ("index lesion") was found in all. DWI-hyperintense lesions other than the index lesion ("subsidiary infarctions") were punctate and lay within leptomeningeal artery territories in the majority. As opposed to patients with a single lacunar infarction, patients with a subsidiary infarction more frequently (P<0.05) harbored an identifiable cause of stroke. CONCLUSIONS: Almost 1 of every 6 patients presenting with a classic lacunar syndrome has multiple infarctions demonstrated on DWI. This DWI finding usually indicates an identifiable cause of stroke and therefore may influence clinical decisions regarding the extent of etiologic investigations and treatment for secondary prevention.     

Presence of acute ischaemic lesions on diffusion-weighted imaging is associated with clinical predictors of early risk of stroke after transient ischaemic attack

BACKGROUND: Early risk of stroke after a transient ischaemic attack (TIA) can be reliably predicted with risk scores based on clinical features of the patient and the event, but it is unclear how these features correlate with findings on brain imaging and few studies have investigated this in the subacute phase. METHODS: Two hundred consecutive patients attending a specialist clinic underwent diffusion-weighted brain imaging (DWI) on the day of the clinic (> or =3 days after a TIA) and the presence of recent lesions (positive DWI) was related to the presence of clinical features associated with a high stroke risk and to 2 validated risk scores (ABCD and California). RESULTS: Thirty-one patients (16%) had positive DWI. Increasing ABCD and California scores were associated with positive DWI (p = 0.02 for both) independent of the delay from TIA to scan. CONCLUSION: Presence of recent ischaemic lesions on DWI correlates with validated clinical scores for risk of stroke after TIA in patients scanned subacutely. Future prognostic studies of DWI after TIA should adjust for the risk scores to determine the independent predictive value of DWI and hence the likely role of DWI in refinements of the scores.     

Acute brain MRI–DWI patterns and stroke recurrence after mild-moderate stroke

Brain ischemic lesions identified by diffusion-weighted imaging (DWI) have been shown to predict high risk of early future ischemic events in patients with transient ischemic attacks and minor stroke. The aim of this study is to analyze different brain MRI–DWI patterns in patients with mild-moderate stroke to define acute patterns related with a higher risk of stroke recurrence in long-term follow-up (from 6 to 36 months). Retrospective review of case series from a prospective stroke record including 253 patients with mild-moderate stroke (NIHSS from 1 to 7) and acute MRI–DWI lesions. MRI–DWI lesions were analyzed to determine clinically relevant lesions, based on the number, location, age and affected arterial territories. We defined three patterns: (1) multiple versus single lesions; (2) single deep versus single cortical lesions; and (3) single lesions versus multiple lesions affecting different arterial territories and/or of different age. The impact of these patterns on recurrence was analyzed by Cox regression analysis. 38 patients (15.0%) suffered a recurrence. Univariate analysis showed the risk of recurrence for each pattern. Pattern 1: patients with multiple lesions had greater risk of recurrence than those with single lesions (28.2 vs. 9.9%; OR: 3.75 (95% CI: 1.76–7.27), p < 0.0001). Pattern 2: patients with single cortical lesions had higher risk than those with deep lesions (14.3 vs. 6.7% OR: 2.33 (95% CI: 0.86–6.33), p < 0.089). Pattern 3: patients with multiple DWI in different territories or different age had the highest recurrence rate (30.6%), OR: 4.01 (95% CI: 1.70–9.47), p < 0.001, compared to patients with single lesions. Cox regression analysis adjusted by possible confounders, showed that for pattern 1 the OR for recurrence was 2.49 (95% CI: 1.27–4.89), p = 0.008; for pattern 2, OR:1.99 (95% CI: 0.74–5.37), p = 0.17; for pattern 3, OR: 2.85 (95% CI: 1.31–6.15), p = 0.008. Brain MRI–DWI patterns assessed in the acute phase of mild-moderate stroke are useful to identify those patients at high risk of recurrence.     

Association of ischemic lesion patterns on early diffusion-weighted imaging with TOAST stroke subtypes

BACKGROUND: Different topographic patterns in patients who experience an acute ischemic stroke may be related to specific stroke causes. OBJECTIVE: To determine if lesion patterns on early diffusion-weighted imaging (DWI) are associated with stroke subtypes determined by the TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification. DESIGN: Cross-sectional study. SETTING: General community hospital.Patients We studied 172 consecutive ischemic stroke patients with a symptomatic lesion on DWI performed within 24 hours of stroke onset. MAIN OUTCOME MEASURES: Lesion patterns on DWI were classified into single lesions (corticosubcortical, cortical, subcortical > or =15 mm, or subcortical <15 mm), scattered lesions in one vascular territory (small scattered lesions or confluent with additional lesions), and multiple lesions in multiple vascular territories (in the unilateral anterior circulation, in the posterior circulation, in bilateral anterior circulations, or in anterior and posterior circulations). RESULTS: We found an overall significant relationship between DWI lesion patterns and TOAST stroke subtypes (P<.001). Corticosubcortical single lesions (P =.01), multiple lesions in anterior and posterior circulations (P =.03), and multiple lesions in multiple cerebral circulations (P =.008) were associated with cardioembolism. Multiple lesions in the unilateral anterior circulation (P =.04) and small scattered lesions in one vascular territory (P =.06) were related to large-artery atherosclerosis. Nearly half (11/23) of the patients with a single subcortical lesion that was 15 mm or larger were classified as having cryptogenic strokes (P =.001), although 9 of these patients had a classic lacunar syndrome without cortical hypoperfusion. CONCLUSIONS: Early DWI lesion patterns are associated with specific stroke causes. Conventional 15-mm criteria for lacunes, however, may underestimate the diagnosis of small-vessel occlusion with DWI.     

Incidental DWI Lesions in Patients with Recent Small Subcortical Infarctions

ObjectivesIncidental acute ischemic lesions distinct from the primary neurological insult are identified on diffusion-weighted imaging (DWI) in a number of conditions where cerebral microvascular pathology plays a central role. Another major manifestation of cerebral small vessel disease (CSVD) is ischemic stroke named as recent small subcortical infarction (RSSI). In this study, we sought to identify the prevalence and predictors of incidental DWI lesions in patients with RSSI.Materials and MethodsWe retrospectively analyzed a consecutive series of acute ischemic stroke patients with DWI evidence of acute lesions solely localized to perforator artery territories. Images were evaluated for the presence of additional acute or subacute subcortical DWI lesions, apart from the symptomatic lesion. Clinical features including vascular risk factor burden, together with imaging markers of chronic CSVD, were compared among patients with and without incidental acute or subacute lesions.ResultsAmong 396 patients with no alternate stroke etiology additional incidental subcortical DWI bright lesions were identified in 74 (19%) cases. These lesions were primarily localized in the corona radiata, or centrum semiovale. Patients with incidental DWI lesions were more likely to have a history of hypertension, a higher white matter hyperintensities burden in the periventricular and subcortical region, higher perivascular spaces burden in the basal ganglia, multiple cerebral microbleeds, and multiple chronic lacunes. Presence of multiple chronic lacunes (OR 5.98, 95% CI 3.18-11.24) and ≥2 vascular risk factors (OR 2.03, 95% CI 1.05-3.91) stood out as features significantly associated with incidental DWI lesions in multivariate analysis.ConclusionsOur study shows that acute or subacute ischemic lesions can be incidentally detected in approximately one-fifth of patients with RSSI. This observation suggests that the course of CSVD might be more active, temporally and spatially, in a distinct subgroup of RSSI patients, specifically those with a higher chronic lacune and vascular risk factor burden.     

Analysis of Clinical Symptoms and Brain MRI of Heat Stroke: 2 Case Reports and a Literature Review

Introduction: Heat stroke is defined as high body temperature causing multiple organ failure, psychological change, seizure, and consciousness disturbance, which lead to its high mortality rate. However, the involvement of brain injury is rare, and heat-stroke has only been reported in a few case reports or case series. The purpose of this case study was to evaluate the clinical symptoms and radiological features of heat stroke. Methods: We reviewed our hospital records and previously published reports to find cases of heat stroke. We excluded those with unknown clinical features or radiological findings. Results: We retrieved 2 cases of heat stroke from our hospital, which presented as extensive lesions on brain imaging that led to disseminated intravascular coagulation and death within a few days. In 21 previously reported cases of heat stroke, similar brain lesions were noted. These were classified as infarction/posterior reversible encephalopathy syndrome (PRES)-like lesions. The patients who developed PRES-like lesions and survived often developed cerebellar sequelae. Conclusion: The mechanism of heat stroke is presumed to be multifactorial. Ischemic-like lesions result from hypovolemia and unusual coagulation, whereas PRES-like lesions are caused by direct heat and vasogenic edema due to hypercytokinemia. We need to consider the above mentioned conditions when evaluating heat stroke.     

Pathophysiological topography of acute ischemia by combined diffusion-weighted and perfusion MRI.

BACKGROUND AND PURPOSE: Combined echoplanar MRI diffusion-weighted imaging (DWI), perfusion imaging (PI), and magnetic resonance angiography (MRA) can be used to visualize acute brain ischemia and predict lesion evolution and functional outcome. The appearance of a larger lesion by PI than by DWI quantitatively defines a mismatch of potential clinical importance. Qualitative lesion variations exist in the topographic concordance of this mismatch. We examined both the topographic heterogeneity and relative frequency of mismatched patterns in acute stroke using these MRI techniques. METHODS: Acute DWI, PI, and MRA studies of 34 prospectively recruited patients with supratentorial ischemic lesions scanned within 24 hours of stroke onset (range 2.5 to 23.3 hours, 12 patients <6 hours) were analyzed. RESULTS: Ischemic lesions were predominantly in the middle cerebral artery (MCA) territory (94%), with DWI lesions most commonly affecting the insular region. Mismatched patterns with PI lesion larger than DWI lesion occurred in 21 patients (62% overall), in all 4 patients imaged within 3 hours, and in 44% of patients imaged after 18 hours. A patient with a large PI but no DWI lesion and severe clinical deficit at 2.5 hours after stroke onset recovered completely. Regional variations in DWI and PI lesion loci were found, inferring site of proximal MCA occlusion, embolic pathogenesis, and regional arterial reperfusion. CONCLUSIONS: Analysis of the topographic concordance of PI and DWI lesions in acute stroke reveals regional PI lesions without concomitant DWI lesions, which do not necessarily progress to infarction but may suggest stroke pathogenesis and site of current arterial occlusion. Location of DWI lesions may suggest an earlier site of arterial occlusion and regions of maximal perfusion deficit.     

Internal Border Zone Lesions as a Predictor of Early Neurological Deterioration in Minor Stroke Patients with Severe Arterial Steno‐Occlusion

Background: Early neurological deterioration (END) of acute ischemic stroke may be important because it can predict clinical outcomes. We described several cases with similar clinical findings but different outcomes and analyzed the characteristics of their imaging studies. We retrospectively analyzed minor stroke patients with severe arterial stenosis within 6 hours of stroke onset. We defined END as 4 or more deterioration of the National Institutes of Health Stroke Scale score. Diffusion‐weighted imaging (DWI) lesions were classified as lesions of the pial artery (PI), perforating artery (PAI) and border‐zone (BZ). Results: We consecutively analyzed a total of 12 subjects in this study. The patterns of initial DWI lesions were internal BZ (50%), PI (50%), PAI (25%), and cortical BZ (16.7%). Among them, the number of subjects with END was 5, and the frequency of internal BZ on initial DWI was significantly higher in patients with END than in those without. Conclusions: In conclusion, the results of this study suggest that when internal BZ infarcts are detected in patients with acute minor strokes accompanied by severe arterial stenosis, close observation and careful management should be performed because END can be induced at an early stage.