Diffusion-weighted Imaging Lesion Patterns Research Articles

Association between fluid-attenuated inversion recovery vascular hyperintensity and outcome varies with different lesion patterns in patients with intravenous thrombolysis

Background and purposeTo evaluate relationship between fluid-attenuated inversion recovery vascular hyperintensity (FVH) after intravenous thrombolysis and outcomes in different lesion patterns on diffusion-weighted imaging (DWI).MethodsPatients with severe internal carotid or...

D-dimer and diffusion-weighted imaging pattern as two diagnostic indicators for cancer-related stroke: A case-control study based on the STROBE guidelines.

The aim of this study was to evaluate the risk factors and elucidate the clinical characteristics of cancer-associated ischemic stroke to differentiate it from conventional ischemic stroke in China and East Asia. Between June 2012 and June 2016, a retrospective analysis was performed on 609 stroke patients with cancer. They were divided into 3 groups: cancer-stroke group (CSG, 203 cases), stroke group (SG, 203 cases), and cancer group (CG, 203 cases). The d-dimer levels and diffusion-weighted imaging lesion (DWI) pattern were compared to an age- and sex-matched control group. The most common cancer types were colorectal cancer (20.2%) and lung cancer (18.72%). The average d-dimer level in stroke patients and cancer patients were 0.34 and 1.50 mg/L, respectively. The descending levels of d-dimer from cancer types were lung cancer (2.06 mg/L), pancreas (1.74 mg/L), gastric (1.61 mg/L), among others. Univariate analysis of the CSG and the others shows there were significant differences in the prevalence of the levels of d-dimer and DWI pattern, hypertension, diabetes mellitus, and thrombus. CSG has a unique pathological characteristic including high plasma d-dimer levels and multiple vascular lesions. The results show that d-dimer and DWI can be used as diagnostic index in clinical practice.

Diffusion-Weighted Imaging Patterns According to the Right-to-Left Shunt Amount in Cryptogenic Stroke

Background: Although patent foramen ovale (PFO) is considered to be the main cause of cryptogenic stroke, it is difficult to define “true” PFO-related stroke. Objective: In this study, we evaluated comprehensive diffusion-weighted imaging (DWI) findings in patients with cryptogenic stroke according to the right-to-left shunt (RLS) amounts on transcranial Doppler (TCD) sonography. Methods: We assessed consecutive patients with cryptogenic stroke between October 2010 and 2018. The RLS amount on TCD was assessed according to the International Consensus Criteria (ICC). Massive RLS was defined as the highest category of ICC (Curtain pattern). We assessed DWI findings, including the location of lesions, involved vascular territory, and DWI lesion patterns. Results: A total of 100 consecutive patients with cryptogenic stroke were assessed, and PFO was found in 59 patients. In multivariable analyses, massive RLS was noted to be positively associated with the presence of cortical lesion (adjusted OR [aOR] 15.75, 95% CI 1.94–127.71, p = 0.010), multiple territory involvement (aOR 5.24, 95% CI 1.57–17.53, p = 0.007), and number of DWI lesions (beta 0.713, 95% CI 0.245 to 1.181, p = 0.003) after adjusting for confounders. Conversely, massive RLS showed inverse correlations with posterior circulation involvement (aOR 0.22, 95% CI 0.06–0.87, p= 0.031) and number of large DWI lesions (beta –0.328, 95% CI –0.629 to –0.026, p = 0.034). Conclusions: We demonstrated that massive RLS on TCD was associated with multiple, small-scattered cortical lesion in patients with cryptogenic stroke. These DWI pattern is highly suggestive of PFO-related stroke.

Clinical and radiological factors associated with unfavorable outcome after intravenous thrombolysis in patients with mild ischemic stroke

BackgroundA significant proportion of patients with mild ischemic stroke become disabled despite receiving intravenous thrombolytic therapy. The purpose of this study was to assess the clinical and radiological factors associated with unfavorable outcomes in patients with minor ischemic stroke that received intravenous recombinant tissue plasminogen activator (rt-PA) therapy.MethodsWe identified anterior circulation stroke patients with initial National Institutes of Health Stroke Scale (NIHSS) scores ≤5 who received intravenous thrombolysis within 4.5 h of stroke onset and had pretreatment magnetic resonance (MR)/MR angiography using our prospective stroke database. We analyzed baseline characteristics, infarction patterns on diffusion-weighted imaging (DWI), and steno-occlusive lesions on MR angiography. Unfavorable outcome was defined as a modified Rankin Scale (mRS) score ≥ 2 at 90 days. Logistic regression was used to determine independent predictors of unfavorable outcomes.ResultsAmong 121 patients (85 men; mean age, 63.4 ± 11.3 years) included in this study, 46 (38%) had unfavorable outcomes at 90 days and DWI lesion patterns showing infarction in the deep middle cerebral artery (MCA) territory involving the perforating artery area was observed in 47 (38.8%) patients. On multivariable analysis, unfavorable outcomes at 90 days were associated with diabetes [odds ratio (OR), 3.41; 95% confidence interval (CI), 1.06–10.9; P = 0.039), NIHSS score on admission (OR, 2.11; 95% CI, 1.35–3.30; P = 0.001), and infarction in the deep MCA territory on DWI (OR, 4.19; 95% CI, 1.63–10.8; P = 0.003). Lesions in the deep MCA territory was independently associated with early neurological deterioration (P = 0.032). The patients without deep MCA territory infarction had a higher prevalence of cardiac embolism (P = 0.009).ConclusionsHigher NIHSS scores, diabetes, and deep MCA territory infarction may be useful for predicting unfavorable outcomes in patients with minor stroke treated with intravenous rt-PA therapy.

Different infarction patterns in patients with aortic atheroma compared to those with cardioembolism or large artery atherosclerosis.

Aortic atheroma is a known cause of ischemic stroke. However, it is unclear whether ischemic stroke is caused by emboli from aortic atheroma or by accompanying atherosclerosis. In this study, we evaluated lesion patterns of patients with complex aortic plaque (CAP) to assume the underlying pathophysiology. Acute ischemic stroke patients who underwent transesophageal echocardiography were included. CAP was defined as a plaque in the proximal aorta ≥4mm thick or with a mobile component. The diffusion-weighted imaging lesion patterns of patients with CAP were compared to those with large arterial atherosclerosis (LAA) or cardioembolism (CE). A total of 64 CAP patients, 127 LAA patients, and 80 CE patients were included. Small cortical pattern was more common in the CAP group (45.3%) than in the LAA (7.9%, p < 0.001) or the CE group (23.8%, p = 0.018). A large cortical pattern was more common in the CE group than in the CAP group (p < 0.001), whereas subcortical only pattern tended to be more common in the CAP group than in the CE group (p = 0.057). In multinominal analysis, the CAP group was more likely to have a small cortical lesion than the LAA group [odds ratio (OR) 14.63; 95% confidence interval (CI) 4.67-45.85] or the CE (OR 3.69, 95% CI 1.19-11.39) group. In conclusion, patients with CAP frequently had small cortical lesions or subcortical single lesion. These findings imply that ischemic stroke in aortic atheroma patients is associated with either small emboli or small artery disease.

DWI Lesion Patterns Predict Outcome in Stroke Patients with Thrombolysis

Background: Lesion patterns may predict prognosis after acute ischemic stroke within the middle cerebral artery (MCA) territory; yet it remains unclear whether such imaging prognostic factors are related to patient outcome after intravenous thrombolysis. Aims: The aim of this study is to investigate the clinical outcome after intravenous thrombolysis in acute MCA ischemic strokes with respect to diffusion-weighted imaging (DWI) lesion patterns. Methods: Consecutive acute ischemic stroke cases of the MCA territory treated over a 7-year period were retrospectively analyzed. All acute MCA stroke patients underwent a MRI scan before intravenous thrombolytic therapy was included. DWI lesions were divided into 6 patterns (territorial, other cortical, small superficial, internal border zone, small deep, and other deep infarcts). Lesion volumes were measured by dedicated imaging processing software. Favorable outcome was defined as modified Rankin scale (mRS) of 0-2 at 90 days. Results: Among the 172 patients included in our study, 75 (43.6%) were observed to have territorial infarct patterns or other deep infarct patterns. These patients also had higher baseline NIHSS score (p < 0.001), a higher proportion of large cerebral artery occlusions (p < 0.001) and larger infarct volume (p < 0.001). Favorable outcome (mRS 0-2) was achieved in 89 patients (51.7%). After multivariable analysis, groups with specific lesion patterns, including territorial infarct and other deep infarct pattern, were independently associated with favorable outcome (OR 0.40; 95% CI 0.16-0.99; p = 0.047). Conclusions: Specific lesion patterns predict differential outcome after intravenous thrombolysis therapy in acute MCA stroke patients.

Acute diffusion-weighted imaging lesion patterns predict progressive small subcortical infarct in the perforator territory of the middle cerebral artery.

Single small subcortical infarct (SSSI) is generally considered to have a fair outcome. However, early neurological deterioration (END), a relatively unfavorable clinical course occurring during the acute phase of infarction, is not uncommon. The aim of this study was to investigate the relationship between lesion patterns detected by diffusion-weighted imaging (DWI) and the presence of END in patients with acute SSSI in the perforator territory of the middle cerebral artery (MCA). Three hundred twelve patients with acute SSSI in the perforator territory of MCA were prospectively recruited from Jinling Hospital between January 2010 and May 2013. Acute DWI lesion patterns were classified as proximal SSSI (pSSSI) or distal SSSI (dSSSI) patterns, according to the relationship between lesion location and the parent artery. Neurological deficits were evaluated using the National Institutes of Health Stroke Scale (NIHSS) at admission and continued over the following 72 h 1-3 times a day. END was defined as an increase in NIHSS score ≥ 2 points during the first 72 h after admission. Of the total 312 patients, the pSSSI pattern was found in 139 (44.55%) patients and the dSSSI pattern in 173 (55.45%) patients. Statistical analysis suggested that the indicators for small-artery disease (hypertension and leukoaraiosis) and atherosclerosis (diabetes mellitus and cerebral atherosclerosis) significantly differed according to lesion patterns (P < 0.05). During hospitalization, 88 (28.21%) patients experienced END. Univariate analysis revealed that female sex (P = 0.004), pSSSI pattern (P < 0.001), initial NIHSS (P = 0.001), lesion diameter (P = 0.005), ipsilateral large-artery stenosis (P = 0.008), and concomitant intracranial atherosclerotic stenosis (P = 0.021) were significantly associated with END. After adjusting for confounding factors, pSSSI pattern was an independent predictor of END (OR 1.871, 95% CI 1.095-3.198, P = 0.022). In the further subgroup analysis of patients with different etiologies, pSSSI pattern was found to be independently associated with END in patients with large-artery atherosclerosis (OR 3.593, 95% CI 1.268-11.057, P = 0.026) and in patients with small-artery disease (OR 2.523, 95% CI 1.121-5.676, P = 0.025), but not in patients with cardioembolism (OR 0.854, 95% CI 0.147-4.953, P = 0.861). pSSSI pattern was closely related to END in acute SSSI caused by large-artery atherosclerosis and small-artery disease in the perforator territory of the MCA.

The Relationship between Neurological Worsening and Lesion Patterns in Patients with Acute Middle Cerebral Artery Stenosis

Background: Intracranial atherosclerotic disease is one of the most common causes of ischemic stroke especially in Asians, Hispanics and blacks. Although middle cerebral artery (MCA) stenosis is increasingly being recognized with the advent of magnetic resonance angiography (MRA) or transcranial Doppler ultrasonography, few studies have focused on acute neurological worsening (NW) in patients with MCA stenosis. We investigated the relationship between NW and lesion patterns detected by diffusion-weighted imaging (DWI). Methods: We studied 44 consecutive patients out of a total of 2,863 consecutive patients who had symptomatic lesions in the territory of the MCA and in whom MRA and/or conventional angiography showed isolated MCA stenosis ≥50% in the MCA trunk. Acute DWI lesion patterns were classified as follows: (1) pial artery territory infarcts (PAI); (2) small cortical and/or subcortical infarcts (SCS); (3) deep penetrating artery territory infarcts (DPI); (4) cortical border zone infarcts (CBZ), and (5) internal border zone infarcts (IBZ). NW was defined as worsening by ≥2 points on the National Institutes of Health Stroke Scale (NIHSS) during the first 7 days. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3 months after stroke onset. Poor outcome was defined as ≥3 on the mRS. The severity of MCA stenosis on MRA was further categorized as 50-75% (moderate) and >75% or focal signal loss with the presence of distal MCA signal (severe). Results: There were 14 patients (31.8%) who showed NW and 16 patients (36.3%) who showed poor outcomes. Nine of the 14 patients with NW showed poor outcomes (64.2%). The most frequent lesions in the present study were SCS (n = 16, 36.3%), followed by IBZ (n = 12, 27.2%) and DPI (n = 11, 25.0%). Prevalence of IBZ was significantly higher in the group with NW compared to that without NW (p = 0.0081), while the prevalence of SCS, DPI, PAI and CBZ did not differ between the two groups. Logistic regression analysis showed significantly high age- and sex-adjusted odds ratios (ORs) for NW only for IBZ (OR 10.9, p = 0.0051). The degree of stenosis did not correlate with NW and lesion patterns. Conclusions: Only IBZ among various lesion patterns correlated strongly with NW. IBZ are considered to be more associated with hemodynamic compromise, while embolic pathogeneses contribute more to CBZ or SCS. Early interventional medical treatments such as thrombolytic or anti-platelet therapy or stenting should be considered in cases of IBZ in MCA stenosis.

Examination Timing and Lesion Patterns in Diffusion-weighted Magnetic Resonance Imaging of Patients with Classically Defined Transient Ischemic Attack

This study investigated factors associated with the presence of acute ischemic lesions after transient ischemic attack (TIA), using diffusion-weighted imaging (DWI) data from a multicenter retrospective, observational study. Of the 464 patients admitted to 13 stroke centers in Japan within 7 days after TIA onset, 458 patients underwent a DWI examination in this registry. Patients were divided into those with acute ischemic lesions and those without. We analyzed associations between DWI lesions and baseline characteristics, including age, sex, comorbidities, large artery atherosclerosis (LAA), type and duration of symptoms, the presence of multiple occurrences of TIA within 90 days before hospital visits (multiple TIAs) and the time from symptom onset to DWI examination (time-to-DWI). Among the 458 patients (291 men, 68.4±13.2 years old), 374 (81.7%) underwent a DWI examination within the initial 24 hours after the symptom onset. DWI lesions were found in 96 patients (21.0%), and divided into a single lesion (56 patients, 12.2%) or multiple lesions (40 patients, 8.7%). The presence of DWI lesions had an association with male sex (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.07-3.29), time-to-DWI longer than 24 hours (OR 2.96; CI 1.57-5.52), and intracranial LAA (OR 1.99; CI 1.02-3.79). The presence of a single DWI lesion had an association with atrial fibrillation (OR 2.70; CI 1.41-5.03), and multiple DWI lesions did with time-to-DWI longer than 24 hours (OR 6.20; CI 2.60-15.20), multiple TIAs (OR 3.04; CI 1.35-6.76), intracranial LAA (OR 3.63; CI 1.44-8.89), and extracranial LAA (OR 3.53; CI 1.08-10.78). Acute ischemic lesions on DWI were associated with time-to-DWI and LAA in patients with classically defined TIA. Additionally, we identified some differences in relating factors between patients with single and multiple DWI lesions. These results indicate that time-to-DWI and DWI lesion pattern may be important for the diagnosis and management of TIA.

Stroke and Cancer

The importance of cancer-associated hypercoagulability as a possible stroke etiology in patients with cancer has received relatively little attention to date. A recent study has suggested that cancer-associated hypercoagulation may be of special importance in the absence of conventional stroke mechanisms. We identified patients with ischemic stroke sequentially admitted to our stroke center with the additional diagnosis of active and malignant cancer from 2002 to 2011. By using our prospectively collected stroke, MRI, and laboratory data banks, the etiology and risk factors of stroke, types of cancer, deep vein thrombosis/pulmonary embolism, d-dimer levels, and diffusion-weighted imaging lesion patterns were compared to an age- and sex-matched control group. Patients with cancer with a conventional stroke etiology and patients with an unidentified and/or cancer-associated stroke etiology were analyzed separately. One hundred forty patients with cancer and 140 control subjects were included. Unidentified stroke (P<0.001) and infarction in multiple vascular territories (P<0.001) were significantly more frequent and d-dimer levels significantly higher (P<0.05) in patients with cancer. Vice versa, risk factors such as hypertension (P<0.05) and hyperlipidemia (P<0.01) were more prevalent in control subjects. Deep vein thrombosis and pulmonary embolism were more frequent (P<0.01) and d-dimer levels higher (P<0.01) in the patients with unidentified and/or cancer-associated stroke etiology compared to the patients with cancer with a conventional stroke etiology. Lung and pancreatic cancer were significantly overrepresented and d-dimer levels higher in these patients compared with other patients with cancer (P<0.01). Our data confirm the concept of cancer-associated hypercoagulation as a widely underestimated important stroke risk factor in patients with cancer, especially in those with severely elevated d-dimer levels and in the absence of conventional risk factors.

Association between the Amount of Right-to-Left Shunt and Infarct Patterns in Patients with Cryptogenic Embolic Stroke: A Transcranial Doppler Study

Paradoxical embolism has been documented as a mechanism of cryptogenic embolic stroke. We investigated the frequency of right-to-left shunt in patients with cryptogenic embolic stroke and evaluated the factors associated with diffusion-weighted imaging (DWI) lesion pattern. We analyzed data on 157 consecutive patients with acute ischemic stroke because of presumed cryptogenic embolism. Agitated saline transcranial Doppler study was conducted in all patients to detect right-to-left shunt. We evaluated the association of the amount (microemboli <20 vs. ≥20) and activity (spontaneous vs. after Valsalva maneuver only) of right-to-left shunt with diffusion-weighted imaging lesion patterns. Right-to-left shunt was observed in 96 (61·1%) patients. The multiplicity and distribution of diffusion-weighted imaging lesions did not differ depending on the amount and activity of right-to-left shunt. However, the size of diffusion-weighted imaging lesions differed depending on the amount of right-to-left shunt (P = 0·019). Right-to-left shunt was more frequently observed in patients with small (<1 cm) infarcts than in those with a large infarct (66·7% vs. 45·9%), and most patients with a larger amount of right-to-left shunt were found to have small infarcts on diffusion-weighted imaging (80%). The clinical characteristics, including Framingham stroke risk strategy, did not differ between the groups. Our results indicate that the amount of right-to-left shunt determines the Diffusion-weighted imaging lesion patterns and suggest that mechanisms of stroke other than paradoxical mechanism may play an important role in patients with large cryptogenic embolic stroke.

Branch occlusive disease

We evaluated the clinicoradiologic characteristics of patients with branch occlusive disease (BOD)-type intracranial atherosclerotic stroke (ICAS) compared with those of patients with non-BOD-type ICAS or with small artery disease (SAD). We analyzed 201 consecutive patients with acute infarcts within the middle cerebral artery (MCA) distribution but no demonstrable carotid or cardiac embolism sources. According to the diffusion-weighted imaging (DWI) distribution and the presence of ipsilateral MCA stenosis, of any degree, on magnetic resonance angiography (3-T MRI), we divided patients into 3 groups: 1) BOD: subcortical infarcts with MCA stenosis (n = 46); 2) non-BOD: infarcts beyond the subcortical area with MCA stenosis (n = 52); and 3) SAD (n = 103). We compared risk factors, degree of stenoses and distribution, and radiologic features of microangiopathy (leukoaraiosis and cerebral microbleeds) among the groups. Risk factor profiles were similar among the groups, except that hypertension and current smoking were more prevalent in the non-BOD than in the BOD group (p = 0.032 and 0.045). The relevant MCA had more severe and focal stenosis in the non-BOD than in the BOD group (stenosis of ≥70%; 76.9% vs 28.3%; p < 0.001), but the degree of nonrelevant stenosis was similar across the groups. Although clinical features, DWI lesion patterns, and microangiopathy findings were similar between the BOD and SAD groups, nonrelevant stenosis was more prevalent in the BOD than in the SAD group (p < 0.01). BOD is prevalent (47% of ICAS) and shares common characteristics with non-BOD-type ICAS, although its clinicoradiologic features may resemble those of SAD. The morphologic characteristics of stenosis and risk factors may associate with a stroke phenotype in patients with ICAS.

Stroke Occurrence and Patterns Are Not Influenced by the Degree of Stenosis in Cervical Artery Dissection

In stroke attributable to spontaneous dissection of the cervical artery, it is unclear whether the occurrence and pattern of stroke depend on the degree of stenosis. In 147 consecutive dissection of the cervical artery patients with (n=88) and without stroke (n=59), we compared the number, volume, and patterns of cerebral diffusion-weighted imaging stroke lesions among patients with <70% stenosis (Group 1), ≥70% stenosis (Group 2), and occlusion (Group 3). The presence (26 of 45 in Group 1, 32 of 59 in Group 2, 30 of 43 in Group 3; P=0.27) and the number of diffusion-weighted imaging lesions (mean±SD [interquartile range], 3.5±3.9 [1-4] in Group 1; 4.2±4.1 [1-5] in Group 2; 3.3±4.0 [1-3] in Group 3; P=0.85) were independent of lumen patency, whereas volume of diffusion-weighted imaging lesions was larger in occlusive dissection of the cervical artery (82±90 mm [17-91] versus 34±54 [2-48]; P=0.03). There were no differences in the breakdown of diffusion-weighted imaging lesion patterns according to degree of stenosis. The occurrence and diffusion-weighted imaging lesion patterns in dissection of the cervical artery patients may not be influenced by the degree of stenosis of the dissected artery. Occlusive dissection of the cervical artery was associated with larger infarcts.

The determinants of stroke phenotypes were different from the predictors (CHADS2 and CHA2DS2-VASc) of stroke in patients with atrial fibrillation: a comprehensive approach

BackgroundAtrial fibrillation (AF) is a leading cause of fatal ischemic stroke. It was recently reported that international normalized ratio (INR) levels were associated with infarct volumes. However, factors other than INR levels that affect stroke phenotypes are largely unknown. Therefore, we evaluated the determinants of stroke phenotypes (pattern and volume) among patients with AF who were not adequately anticoagulated.MethodsWe analyzed data pertaining to consecutive AF patients admitted over a 6-year period with acute MCA territory infarcts. We divided the patients according to DWI (diffusion-weighted imaging) lesion volumes and patterns, and the relationship between stroke predictors (the CHADS2 and CHA2DS2-VASc score), systemic, and local factors and each stroke phenotype were then evaluated.ResultsThe stroke phenotypes varied among 231 patients (admission INR median 1.06, interquartile range (IQR) 1.00-1.14). Specifically, (1) the DWI lesion volumes ranged from 0.04-338.62 ml (median 11.86 ml; IQR, 3.07-44.20 ml) and (2) 46 patients had a territorial infarct pattern, 118 had a lobar/deep pattern and 67 had a small scattered pattern. Multivariate testing revealed that the CHADS2 and CHA2DS2-VASc score were not related to either stroke phenotype. Additionally, the prior use of antiplatelet agents was not related to the stroke phenotypes. Congestive heart failure and diastolic dysfunction were not associated with stroke phenotypes.ConclusionsThe results of this study indicated that the determinants of stroke phenotypes were different from the predictors (i.e., CHADS2 and CHA2DS2-VASc score) of stroke in patients with AF.

MRI Findings May Predict Early Neurologic Deterioration in Acute Minor Stroke or Transient Ischemic Attack due to Intracranial Atherosclerosis

Background: Patients with intracranial atherosclerosis (ICAS) are at high risk of early recurrence or neurologic deterioration. Although minor stroke and transient ischemic attack (TIA) seem benign, their occurrence in patients with ICAS may lead to early neurological deterioration (END). We aimed to identify factors associated with END in ICAS patients presenting with acute minor stroke or TIA, with a focus on early MRI findings. Methods: This was a retrospective analysis of consecutive patients with acute minor stroke or TIA admitted within 12 h of symptom onset. Patients with moderate-severe stenosis of the middle cerebral artery or basilar artery (BA) were included. All patients underwent MRI, including diffusion-weighted imaging (DWI), and magnetic resonance angiography. DWI lesion patterns were classified as perforating artery infarcts, pial infarcts, territorial infarcts and border zone infarcts (BIs). END was diagnosed as an increase of ≧4 points on the National Institutes of Health Stroke Scale from baseline during the 1st week. Results: Of the 95 patients enrolled in the study, 14 (14.7%) developed END. Independent predictors of END were the presence of BIs on baseline DWI (odds ratio, OR, 7.21; 95% confidential interval, CI, 1.88–27.66; p = 0.004) and BA disease (OR, 4.33; 95% CI, 1.11–16.92; p = 0.035). Conclusions: ICAS patients with BI and BA disease are at high risk of END after minor stroke or TIA. Early radiological findings may be helpful in predicting END and guiding early treatment strategies.

Difference in Infarct Volume and Patterns between Cardioembolism and Internal Carotid Artery Disease: Focus on the Degree of Cardioembolic Risk and Carotid Stenosis

Background and Objective: Infarct volume and patterns may vary according to the stroke subtype. Within each stroke subtype, however, it is not clear if the infarct volume and patterns are affected by the risk of cardioembolism (CE) and the degree of arterial stenosis. Patients and Methods: We included consecutive patients with acute symptomatic ischemic lesions on diffusion-weighted imaging (DWI) performed within 48 h of symptom onset who had CE or internal carotid artery disease (ICAD). CE was divided into high-risk and medium-risk groups, and ICAD was divided into ICA occlusion (ICAO) and ICA stenosis (ICAS ≧50%) groups. DWI lesion patterns were classified as single versus multiple, and as large territorial versus perforating artery (large ≧2 cm, small <2 cm) versus pial artery versus border zone infarct. Infarct volumes and National Institutes of Health Stroke Scale (NIHSS) scores were obtained. Results: Of the 167 patients included, 120 had CE (98 high-risk, 22 medium-risk) and 47 had ICAD (25 ICAO, 22 ICAS). The infarct volume was largest in the high-risk CE group, followed by the ICAO group. The infarct volumes in the medium-risk CE and ICAS groups were similar. Infarct volumes correlated with NIHSS scores. Single and large territorial infarcts were more common in the high-risk CE group, while multiple lesions as well as pial and border zone infarcts were more frequent in the ICAD subgroups. The lesion patterns of the medium-risk CE and ICAD groups were relatively similar. Conclusions: CE and ICAD have heterogeneous radiologic characteristics depending on the risk of embolism and the degree of carotid stenosis.

Ischemic Stroke in Cancer Patients With and Without Conventional Mechanisms

To assess the precise mechanisms of stroke in cancer patients, we analyzed the data for cancer patients with acute ischemic stroke registered from 6 centers in South Korea. Clinical features, risk factors, diffusion-weighted imaging lesion patterns, and laboratory findings including D-dimer levels were compared between patients with conventional stroke mechanisms (CSMs) and cryptogenic group. A total of 161 patients were included in this study: 97 (60.2%) patients in the CSM group and 64 (39.8%) in the cryptogenic group. Patients in the CSM group were older and vascular risk factors were more prevalent than in the cryptogenic group. Diffusion-weighted imaging patterns of multiple lesions involving multiple arterial territories were observed more frequently in the cryptogenic group than in the CSM group. In addition, levels of the D-dimer were higher in the cryptogenic group than in the CSM group (11.5+/-14.6 versus 3.6+/-10.3 microg/dL). In multivariate analysis, the diffusion-weighted imaging lesion pattern of multiple vascular territories (odds ratio, 11.2; 95% CI, 3.74 to 33.3), and D-dimer levels of >1.11 microg/dL (odds ratio, 10.6; 95% CI, 3.29 to 33.8) were associated independently with the cryptogenic group. Stroke outside of CSM occurred in a large number in cancer patients. In stroke patients with cancer, d-dimer levels and diffusion-weighted imaging lesion patterns may be helpful in early identification of non-CSMs (especially coagulopathy associated with cancer) and possibly in guiding preventive strategies for stroke.

Contribution of Diffusion and Perfusion MRI Patterns in Small Subcortical Infarcts

Purpose: We evaluated whether combined diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) could identify stroke subtypes in patients with acute small subcortical infarcts (SSI), according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classifications. Materials and Methods: A total of 182 patients with acute SSI in the middle cerebral artery territory were studied retrospectively. Lesions on DWI were evaluated as number, location, and combined cortical spotty lesion. PWI using mean transit time (MTT) was classified as type 1 (normal perfusion), type 2 (matched perfusion-diffusion), and type 3 (mismatched perfusion-diffusion). Results: There were 126 (69.2%) patients with small vessel disease, 46 (25.3%) with large artery atherosclerosis, and 10 (5.5%) with cardio-embolism in patients with acute SSI within the middle cerebral artery territory. We found a significant overall association of DWI and PWI lesion patterns and classification with stroke subtype by using the TOAST criteria (p

Determinants of the distribution and severity of hypoperfusion in patients with ischemic stroke

In acute cerebral ischemia, two variables characterize the extent of hypoperfusion: the volume of hypoperfused tissue and the intensity of hypoperfusion within these regions. We evaluated the determinants of the intensity of hypoperfusion within oligemic regions among patients who were eligible for recanalization therapy for acute ischemic stroke. We analyzed data, including pretreatment diffusion-weighted imaging (DWI) and perfusion-weighted imaging, on 119 patients with acute middle cerebral artery infarctions. The intensity of hypoperfusion within oligemic regions was characterized by the hypoperfusion intensity ratio (HIR), defined as the volume of tissue with severe hypoperfusion (Tmax > or = 8 seconds) divided by the volume of tissue with any hypoperfusion (Tmax > or = 2 seconds). Based on the DWI data, we divided the patients into four stroke phenotypes: large cortical, small (< 1 cm diameter) cortical, border-zone, and deep pattern. The mean (SD) volume of severe hypoperfusion was 54.6 (52.5) mL, and that of any hypoperfusion was 140.8 (81.3) mL. The HIR ranged widely, from 0.002 to 0.974, with a median of 0.35 (interquartile range 0.13-0.60). The volume of any hypoperfusion did not predict the intensity of hypoperfusion within the affected region (r = 0.10, p = 0.284). Angiographic collateral flow grade was associated with HIRs (p value for trend = 0.019) and differed among DWI lesion patterns. In multivariate analysis, diastolic pressure on admission (odds ratio 0.959, 95% CI 0.922-0.998) and DWI pattern of deep infarcts (odds ratio 18.004 compared with large cortical pattern, 95% CI 1.855-173.807) were independently associated with a low HIR. The intensity of hypoperfusion within an oligemic field is largely independent of the size of the oligemia region. Predictors of lesser intensity of hypoperfusion are lower diastolic blood pressure and presence of a deep diffusion-weighted imaging lesion pattern.

Response to Letter by Phan et al

HomeStrokeVol. 37, No. 11Response to Letter by Phan et al Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBResponse to Letter by Phan et al Seok Woo Yong Oh Young Bang Seok Woo YongSeok Woo Yong Department of Neurology, Ajou University School of Medicine, Suwon, South Korea Search for more papers by this author Oh Young BangOh Young Bang Department of Neurology, Stroke and Cerebrovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine,, Seoul, South Korea Search for more papers by this author Originally published21 Sep 2006https://doi.org/10.1161/01.STR.0000244813.13221.ccStroke. 2006;37:2659Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: September 21, 2006: Previous Version 1 Response:We thank Dr Phan and his colleagues for their comments. They pointed out that the relationship between internal border-zone (IBZ) infarcts and severe carotid artery stenosis/occlusion has not been demonstrated in some studies. As we mentioned in our article, this inconsistency is likely to have resulted from (a) not using diffusion-weighted imaging (DWI) and (b) not considering the stenosis of the middle carotid artery.1 The articles that Dr Phan et al mentioned are no exception.We agree that stroke topography does not equate with stroke mechanism, ie, hemodynamic versus nonhemodynamic. In addition, it may be difficult to separate these 2 mechanisms of stroke because a synergic association of these 2 mechanisms has been postulated.2 As Phan et al commented, the use of hemodynamic and nonhemodynamic mechanisms rather than the topographic terms for border-zone infarcts may be more ideal. However, the pathological and imaging characteristics of border-zone infarcts are well described and easily recognizable in clinical practice, while it is impossible to perform comprehensive workups in all patients with border-zone infarcts. More importantly, different types of border-zone infarcts may require different therapeutic approaches. In a previous analysis of DWI lesion patterns, an unstable hospital course (often with enlargement of the infarct) and poor long-term outcome were frequently observed in patients with IBZ infarcts, whereas recurrent strokes after the index stroke were more common in those who had small superficial infarcts, including cortical border-zone (CBZ) infarcts. These findings suggest that the DWI lesion pattern is helpful in recognizing the likely differences in the early prognostic end points after ischemic stroke, and the topographic approach may guide targeted interventions to prevent negative outcomes.3Concerning the topographic approach, it is well known that the vascular territories can vary greatly across individuals, which might cause a territorial infarct to be misinterpreted as a border-zone infarct. However, almost every article on border-zone infarcts has used the topographic site as the definition. (How else could one define a border-zone infarction?) This is perhaps an inherent limitation of all studies of border-zone infarction.The significant difference in the degree of stenosis (Figure 2 in the article1) was not the sole evidence that led us to propose different mechanisms in the 2 stroke groups. We also found that patients with IBZ infarcts had fewer small cortical infarcts outside the border-zone territory, and more often assumed a rosary pattern, both of which indicate that IBZ infarction is closely related to hemodynamic compromise. Recently, a comprehensive review of cerebral perfusion studies examined the mechanisms of border-zone infarcts in carotid disease.4 It showed that although severe hemodynamic compromise appears to underlie combined CBZ and IBZ infarction, artery-to-artery embolism might play an important role in isolated CBZ infarcts. Although Phan et al worry about there being insufficient evidence to rule out embolic sources, we believe that the differences we have put forward for the 2 groups strongly indicate that these 2 stroke syndromes have different pathogeneses. Increasing applications of diffusion- and perfusion-weighted imaging and microemboli detection using transcranial Doppler ultrasonography may allow a better understanding of the mechanisms of border-zone infarcts.DisclosuresNone.1 Yong SW, Bang OY, Lee PH, Li WY. Internal and cortical border-zone infarction: clinical and diffusion-weighted imaging features. Stroke. 2006; 37: 841–846.LinkGoogle Scholar2 Caplan LR, Hennerici M. Impaired clearance of emboli (washout) is an important link between hypoperfusion, embolism, and ischemic stroke. Arch Neurol. 1998; 55: 1475–1482.CrossrefMedlineGoogle Scholar3 Bang OY, Lee PH, Heo KG, Joo US, Yoon SR, Kim SY. Specific DWI lesion patterns predict prognosis after acute ischaemic stroke within the MCA territory. J Neurol Neurosurg Psychiatry. 2005; 76: 1222–1228.CrossrefMedlineGoogle Scholar4 Momjian-Mayor I, Baron JC. The pathophysiology of watershed infarction in internal carotid artery disease: review of cerebral perfusion studies. Stroke. 2005; 36: 567–577.LinkGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails November 2006Vol 37, Issue 11 Advertisement Article InformationMetrics https://doi.org/10.1161/01.STR.0000244813.13221.cc Originally publishedSeptember 21, 2006 PDF download Advertisement