Diffusion-weighted Imaging Hyperintensity Research Articles

Reliability of Two Diameters Method in Determining Acute Infarct Size. Validation as New Imaging Biomarker.

BackgroundIn order to select patients most likely to benefit for thrombolysis and to predict patient outcome in acute ischemic stroke, the volumetric assessment of the infarcted tissue is used. However, infarct volume estimation on Diffusion weighted imaging (DWI) has moderate interrater variability despite the excellent contrast between ischemic lesion and healthy tissue. In this study, we compared volumetric measurements of DWI hyperintensity to a simple maximum orthogonal diameter approach to identify thresholds indicating infarct size >70 ml and >100 ml.MethodsPatients presenting with ischemic stroke with an NIHSS of ≥ 8 were examined with stroke MRI within 24 h after symptom onset. For assessment of the orthogonal DWI lesion diameters (od-values) the image with the largest lesion appearance was chosen. The maximal diameter of the lesion was determined and a second diameter was measured perpendicular. Both diameters were multiplied. Od-values were compared to volumetric measurement and od-value thresholds identifying a lesion size of > 70 ml and > 100 ml were determined. In a selected dataset with an even distribution of lesion sizes we compared the results of the od value thresholds with results of the ABC/2 and estimations of lesion volumes made by two resident physicians.ResultsFor 108 included patients (53 female, mean age 71.36 years) with a median infarct volume of 13.4 ml we found an excellent correlation between volumetric measures and od-values (r2 = 0.951). Infarct volume >100 ml corresponds to an od-value cut off of 42; > 70 ml corresponds to an od-value of 32. In the compiled dataset (n = 50) od-value thresholds identified infarcts > 100 ml / > 70 ml with a sensitivity of 90%/ 93% and with a specificity of 98%/ 89%. The od-value offered a higher accuracy in identifying large infarctions compared to both visual estimations and the ABC/2 method.ConclusionThe simple od-value enables identification of large DWI lesions in acute stroke. The cutoff of 42 is useful to identify large infarctions with volume larger than 100 ml. Further studies can analyze the therapeutic utility of this new method.Trail RegistrationClinicalTrials.org NCT00715533

Relationship between magnetic resonance imaging signs and immunohistochemistry of glioblastoma

Objective To study the relationship between magnetic resonance imaging (MRI) signs of glioblastoma (GBM) and the immunohistochemistry of isocitrate dehydrogenase 1 (IDH1), O6-methylguanine-DNA methyltransferase (MGMT). Methods The patients pathologically diagnosed as GBM were collected from January 2008 to December 2013. The relationship between MRI and immunohistochemistry of IDH1 and MGMT before procedure was analyzed. Results A total of 111 patients performed IDH1 and MGMT immunohistochemical examinations for postoperative pathology, 29 patients (26.1%) were IDH1 positive and 60 (54.1%) were MGMT positive. Univariate analysis showed that the maximum diameter of the tumors (χ2=9.400, P=0.009), MRI enhancement (t=2.204, P=0.030), peritumoral edema (PTE) indexed (χ2=6.411, P=0.041), and main invasive sites (t=2.788, P=0.006) were associated with the positive expression of IDH1. Multivariate logistic regression analysis showed that the maximum diameter of the tumors (P=0.015), MRI enhancement (P=0.037), and main invasive sites (P=0.024) were the main factors for predicting IDH1 positive expression, and the maximum diameter of the tumors was the most important predictor (P<0.05). The positive expression of MGMT was associated with the number of lesions (χ2=6.678, P=0.010), magnetic resonance diffusion weighted imaging (DWI) (t= -4.320, P=0.000), cystic change (χ2=16.185, P=0.000), necrosis (χ2=8.325, P=0.004), and main invasion sites (t=2.612, P=0.010). Multivariate logistic regression analysis showed that the number of lesions (P=0.008), cystic change (P=0.000), and DWI (P=0.000) were the major factors for predicting MGMT positive expression, and DWI hyperintensity was the most important predictor (P<0.05). Conclusions The results of IDH1and MGMT immunohistochemistry have some correlations with the performance of tumors on conventional MRI. It is conducive to screening and preliminary determination of the biological behavior of tumors and identifying its prognosis by analyzing the correlation between imaging and pathology. Key words: Glioblastoma; Isocitrate dehydrogenase; O (6)-methylguanine-DNA methyltransferase; Magnetic resonance imaging

Prostatic abscess and seminal vesicle abscess: MRI findings and quantitative analysis of apparent diffusion coefficient values

PurposeTo investigate the conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) findings of prostatic abscess (PA) and seminal vesicle abscess (SVA), and to evaluate the qualitative and quantitative diagnostic value of apparent diffusion coefficient (ADC) for these conditions. Materials and methodsTen patients with PA and 2 patients with SVA who underwent MRI and DWI examinations (b = 0 and 1000 s/mm2) at our institution were enrolled in this study. The diagnoses of all the patients were pathologically and clinically proved. Their conventional MRI and DWI images as well as ADC values were analyzed. The ADC values between PA and surrounding prostate tissues were compared using t test. Statistical significance was inferred at P < 0.05. ResultsSix patients were revealed with multiple foci. The other 6 showed singular lesion, including the 2 with SVA. A total of 23 focal abscesses were demonstrated with iso-low T1WI signal as well as hyperintense T2WI and DWI signals. Four patients with PA presented air within the lesions by both T1WI and T2WI. The mean ADCs of PA, (0.618 ± 0.192) × 10−3 mm2 s−1, were significantly lower than that of surrounding prostate tissues, (1.417 ± 0.147) × 10−3 mm2 s−1 (P = 0.000). ConclusionPA and SVA can be characteristically demonstrated by MRI, and the lesions show especially restricted diffusion by DWI with low ADC values. These demonstrations facilitate their qualitative and quantitative diagnosis.

Abstract W P26: Itemized NIHSS Subsets Predict MRI Positive Strokes In Patients With Mild Deficits

Background: While imaging is useful in confirming the diagnosis of ischemic stroke, negative diffusion weighted imaging (DWI) is reported in up to 10% of patients. We aim to (1) identify predictors of MRI-positive stroke from the itemized NIHSS, and (2) to correlate subsets with infarct volume. Methods: Data were derived from the Stroke Warning Information and Faster Treatment study from 2006 to 2009 among patients with mild deficits (NIHSS 0-5) and attending physician final diagnosis of stroke. Using Medical Image Processing, Analysis, and Visualization (MIPAV, NIH) (Version 7.1.1), we calculated lesion volume (cm3) from DWI sequence. Univariate models studied the association between itemized NIHSS subsets, including cortical deficits (visual field cut, aphasia, or neglect), and presence of DWI hyperintensity and lesion volume. Multivariable regression assessed factors predicting DWI-positive strokes; p&lt;0.05 was considered significant. Results: Of 611 patients with a discharge diagnosis of stroke, 498 underwent MRI and 29.5% were DWI negative. On multivariate analysis, predictors of a positive DWI were NIHSS score of 3-5 (OR= 2.5, 95%CI:1.1-5.5), motor deficits (OR= 1.9, 95%CI:1.1-3.4), and ataxia (OR=3.0, CI:1.5-6.1). All patients with neglect and visual deficits were DWI positive (table). The mean lesion volume in cm3 was larger in patients with NIHSS 3-5 vs. NHSS 0-2 (49.0 vs. 17.3, p=0.002), cortical deficits (112.6 vs. 22.9, p&lt;0.001), neglect (236.6 vs. 29.7, p&lt;0.001), and visual deficits (245.7 vs. 26.4, p&lt;0.001). Other subsets showed no differences. Conclusion: NIHSS score subsets predict DWI positivity and lesion volume in mild strokes. The presence of neglect or visual field deficit on the NIHSS subsets is highly likely to have an MRI correlate even in patients with low NIHSS.

Diffusion-weighted magnetic resonance imaging without bowel preparation for detection of ulcerative colitis.

To evaluate the accuracy of diffusion-weighted imaging (DWI) without bowel preparation, the optimal b value and the changes in apparent diffusion coefficient (ADC) in detecting ulcerative colitis (UC). A total of 20 patients who underwent 3T magnetic resonance imaging (MRI) without bowel preparation and colonoscopy within 24 h were recruited. Biochemical indexes, including C-reactive protein (CRP), erythrocyte sedimentation rate, hemoglobin, leucocytes, platelets, serum iron and albumin, were determined. Biochemical examinations were then performed within 24 h before or after MR colonography was conducted. DWI was performed at various b values (b = 0, 400, 600, 800, and 1000 s/mm(2)). Two radiologists independently and blindly reviewed conventional- and contrast-enhanced MR images, DWI and ADC maps; these radiologists also determined ADC in each intestinal segment (rectum, sigmoid, left colon, transverse colon, and right colon). Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of DWI hyperintensity from various b factors, ADC values and different radiological signs to detect endoscopic inflammation in the corresponding bowel segment. Optimal ADC threshold was estimated by maximizing the combination of sensitivity and specificity. MR findings were correlated with endoscopic results and clinical markers; these findings were then estimated by ROC analysis. A total of 100 segments (71 with endoscopic colonic inflammation; 29 normal) were included. The proposed total magnetic resonance score (MR-score-T) was correlated with the total modified Baron score (Baron-T; r = 0.875, P < 0.0001); the segmental MR score (MR-score-S) was correlated with the segmental modified Baron score (Baron-S; r = 0.761, P < 0.0001). MR-score-T was correlated with clinical and biological markers of disease activity (r = 0.445 to 0.831, P < 0.05). MR-score-S > 1 corresponded to endoscopic colonic inflammation with a sensitivity of 85.9%, a specificity of 82.8% and an area under the curve (AUC) of 0.929 (P < 0.0001). The accuracy of DWI hyperintensity was significantly greater at b = 800 than at b = 400, 600, or 1000 s/mm(2) (P < 0.05) when endoscopic colonic inflammation was detected. DWI hyperintensity at b = 800 s/mm(2) indicated endoscopic colonic inflammation with a sensitivity of 93.0%, a specificity of 79.3% and an AUC of 0.867 (P < 0.0001). Quantitative analysis results revealed that ADC values at b = 800 s/mm(2) differed significantly between endoscopic inflamed segment and normal intestinal segment (1.56 ± 0.58 mm(2)/s vs 2.63 ± 0.46 mm(2)/s, P < 0.001). The AUC of ADC values was 0.932 (95% confidence interval: 0.881-0.983) when endoscopic inflammation was detected. The threshold ADC value of 2.18 × 10(-3) mm(2)/s indicated that endoscopic inflammation differed from normal intestinal segment with a sensitivity of 89.7% and a specificity of 80.3%. DWI combined with conventional MRI without bowel preparation provides a quantitative strategy to differentiate actively inflamed intestinal segments from the normal mucosa to detect UC.

NI-05 * IMMEDIATE POST-RESECTION PERICAVITARIAN DWI HYPERINTENSITY IN GLIOBLASTOMA PATIENTS IS PREDICTIVE OF PATIENT OUTCOME

BACKGROUND: Some investigators studied the impact of postoperative infarction, infection and surgical complications on Glioblastoma patient survival using Magnetic Resonance Diffusion-Weighted Imaging (MR-DWI). We attempt to investigate the prognostic role of postoperative DWI hyperintensity in patients with GBM. METHODS AND MATERIALS: We obtained immediate postoperative (24-72 hours post resection) brain MRI images of 60 GBM patients from our institution's imaging archive and The Cancer Imaging Archive (TCIA). Using 3D Slicer 4.3.1 (http://www.slicer.org) 2 trained neuroradiologists experienced in tumor volumetry segmented residual enhancement on post-contrast T1 Weighted Imaging (T1WI) and pericavitarian edema/invasion on T2 FLAIR sequence. Segmentation maps were then overlaid over Diffusion Weighted Images (DWI) and Apparent Diffusion Coefficient (ADC) maps. ADC values around resection cavity were obtained. We stratified patients into two categories; facilitated diffusion group and restricted diffusion group. We included different variables in our analysis such as, age, gender, preoperative KPS status, tumor location, preoperative volumetric analysis and post operative volumetric data (quantitative evaluation of extent of resection). We used Kaplan Meier curves for survival analysis after adjustment for potential confounding factors, such as age, tumor location and extent of resection. RESULTS: We created a new non-invasive imaging biomarker that can predict patient outcome in immediate postoperative setting. CONCLUSION: DWI radiophenotypes and ADC map values can be used as a non-invasive prognostic tool for patient overall survival and progression-free survival.

Central nervous system lymphoma: a description and analysis of patients’ clinical and radiological features

Background: Central nervous system (CNS) lymphoma is a rare brain neoplasm. Its incidence has increased these years, so it should be considered in the differential diagnosis for mass lesions in the CNS. The aim of the study was to describe the radiological and clinical features of patients with CNS lymphoma.Methods: The study was a retrospective study. All patients histopathologically confirmed to have CNS lymphoma from November 2008 to December 2013 in Siloam Hospital Lippo Village were included in the study. Medical records and patients’ MRI results were retrieved to be analyzed.Results: 32 patients were histopathologically diagnosed to have CNS lymphoma. The patients, mean age was 54 ± 15.01 years with slight male predominance. No patient was immuno compromised (CD4 &gt; 500 cells/µL and leukocyte 5,000-11,000 cells/µL). The median interval between the onset of the initial symptoms and diagnosis is 7 weeks. The most common presenting symptoms were headache, mental changes, and neurological deficits related to the location of lesion. MR images show that most lesions were enhanced with contrast, iso-hypointense in T1 weighted imaging (T1WI), iso- to hypointense with perifocal edema in T2 weighted imaging (T2WI), hyperintense in diffusion weighted imaging (DWI), with the most common location was white matter of cerebral hemisphere on one or more lobes and periventricular area, and the tumor could be single or multiple (24%) without clear edges.Conclusion: Short course of neurological worsening (within weeks) should lead a suspicion toward lymphoma. The characteristics of MR images are markedly enhanced by contrast, iso- to hypointense on T1WI and T2WI, and hyperintense in DWI, involving white matter of cerebral hemisphere and periventricular area.

Acute hyperammonaemic encephalopathy.

A 58-year-old man with chronic hepatitis B and alcoholic liver cirrhosis was admitted following massive haematemesis with a resultant haemorrhagic shock from bleeding oesophageal varices. Despite emergency variceal ligation with haemodynamic stabilization, the patient remained stuporous and developed two generalized tonic–clonic seizures. Neurological examination revealed intact brainstem reflexes, extensor response of the left upper limb to pain stimuli and absent plantar responses. The differential diagnoses at that point in time included hypoxic ischaemic encephalopathy, non-convulsive status epilepticus, Wernicke encephalopathy and hyperammonaemic encephalopathy. His electroencephalogram showed background slowing with no epileptiform activity; urea and electrolyte measurements, glucose and thyroid function test were unremarkable. MRI brain revealed a strikingly bilaterally symmetrical pattern of cortical hyperintensities on T2 and diffusion-weighted images (DWI) (Fig. 1A and B) involving the frontal regions, especially the cingulate gyri (arrow) and insula cortices (arrowhead). See Figure 2 for corresponding apparent diffusion coefficient (ADC). These MRI findings are typical of the regional lesion distribution in acute hyperammonaemic encephalopathy. The diagnosis of hyperammonaemic encephalopathy, most likely precipitated by variceal bleeding complicating pre-existing liver disease, was confirmed by the elevated serum ammonia level of 90 µmol/L (9–35 µmol/L). Figure 1: (A) MRI brain T2-weighted sequence revealed T2 hyperintensity in the bilateral cingulate gyri (white arrow) and insula cortices (arrowhead). (B) DWI sequence showed hyperintensity in the same distribution as the T2 hyperintensitiy in (A). Figure 2: ADC image showed corresponding ADC reduction in regions with DWI hyperintensity as previously seen in Fig. 1B. Although DWI is most commonly used to detect acute cerebral infarction, bilateral abnormal cortical lesions may also be seen in many acute non-stroke conditions such as encephalitis, seizures, hypoxic ischaemic encephalopathy, hypoglycaemia and hyperammonaemia [1]. The symmetrical vulnerability of the insula and cingulate gyri suggests a systemic, metabolic disease, which was helpful in suggesting hyperammonaemic brain damage rather than other possible diagnoses or ischaemic infarction [2]. The corresponding ADC can be reduced acutely with subsequent normalization [3]. Hyperammonaemic encephalopathy may result from chronic liver disease, and also from uncommon inborn errors of metabolism such as citrullinaemia [4] and ornithine transcarbamylase deficiency [5], and drugs such as valproic acid [6]. Recognizing the distinctive findings of acute hyperammonaemia on DWI can be very helpful for early diagnosis and treatment to prevent potentially irreversible neurological damage and death [6].

Stroke : Highlights of Selected Articles

<i>Stroke</i> : Highlights of Selected Articles

MRI abnormality of the pulvinar in patients with status epilepticus

Recently, magnetic resonance imaging (MRI) abnormalities of the pulvinar in patients with epilepsy have received greater attention, but their occurrence and features have not been fully elucidated. Therefore, we investigated the clinical and radiological features of patients with epilepsy who presented MRI abnormalities of the pulvinar. We retrospectively investigated 225 consecutive patients who came to our institute because of seizures and underwent an MRI within 24h. The patients who exhibited pulvinar MRI abnormalities, their profile, seizure type, efficacy of medication, and chronological changes of MRI findings were examined. Out of the 225 patients who underwent MRI within 24h of seizure, 17 exhibited MRI abnormalities of the pulvinar. All of these 17 patients presented status epilepticus. Bilateral pulvinar diffusion-weighted imaging (DWI) hyperintensity was observed in 3 patients and unilateral pulvinar DWI hyperintensity in the other 14. Out of these 14 patients, 7 exhibited DWI hyperintensity in the ipsilateral cerebral cortex, and 10 patients presented an old lesion due to stroke or trauma. Our results demonstrated that the involvement of the pulvinar in status epilepticus is more frequent than expected and consisted of unilateral or bilateral DWI hyperintensities that may completely normalize. These pulvinar MRI abnormalities possibly reflect the epileptogenic hyperexcitation of different cortical areas through their connections with the pulvinar.

Comparison of Fast MRI-based Individual Thrombolysis Therapy for Patients with Superacute Infarction

The aim of this study is to investigate the outcomes of magnetic resonance imaging (MRI)-based individual thrombolysis therapy using recombinant tissue plasminogen activator (rt-PA) in patients with superacute infarction, comparing the outcome in 1 group of patients treated within 4.5 hours compared with 4.5- to 12-hour window treatment group. We studied 135 patients stratified to 2 different groups based on whether they presented with stroke symptoms within 4.5 hours (4.5-hour group, 72 patients) or between 4.5 and 12 hours (4.5- to 12-h group, 63 patients). All patients were treated with rt-PA after MRI confirmed superacute ischemic stroke (hyperintense in diffusion-weighted imaging but no hypointense change in T2-weighted image (T2WI) or fluid-attenuated inversion recovery). Clinical neurologic deficit was evaluated using the National Institutes of Health Stroke Scale on admission, at 24 hours, and 7 days later. A 90-day clinical outcome was assessed using the modified Rankin Scale (mRS). There was no significant difference in the clinical outcome between the patients treated with thrombolysis within the first 4.5 hours and those treated between 4.5 and 12 hours. The 2 groups both had recanalization, mRS, and favorable outcome at 90 days (P > .05). Our study suggested that fast MR-based thrombolysis using rt-PA was safe and reliable in superacute infarction within 4.5 hours and 4.5-12 hours poststroke.

Echographic Risk Index and Cerebral Ischemic Brain Lesions in Patients Randomized to Stenting versus Endarterectomy for Symptomatic Carotid Artery Stenosis

It remains to be determined whether the impact of plaque characteristics on procedural risks differs between carotid artery stenting (CAS) and endarterectomy (CEA). We studied whether quantitative assessment of carotid plaque echolucency on ultrasound predicts the risk of embolism during CAS or CEA. In 50 consecutive patients with symptomatic carotid stenosis randomized to CAS (n = 26) or CEA (n = 24) in the International Carotid Stenting Study (ICSS), semi-automated grayscale measurement of carotid plaques on baseline ultrasound was performed. We determined the grayscale median (GSM), percentage of echolucent plaque area, and a previously defined echographic risk index (ERI) calculated with the echolucent area and degree of stenosis. Brain MRI including diffusion-weighted imaging (DWI) was performed within 7 days before and 3 days after treatment. The primary outcome was the presence of at least 1 new hyperintense DWI lesion (DWI+) after treatment. In the CAS group, DWI+ patients (n = 18) had a significantly higher ERI at baseline (mean 0.11 ± 0.12) than patients without new lesions (n = 8; mean 0.03 ± 0.01; p = 0.012). GSM (mean 26.7 ± 18.7 versus 34.3 ± 8.0, p = 0.16) and echolucent plaque area (mean 42.8 ± 21.1 versus 31.2 ± 8.2, p = 0.054) did not differ significantly. In the CEA group, there were no differences in plaque echogenity measurements between patients with (n = 2) and without DWI lesions (n = 22). Patients with echolucent plaques causing severe narrowing are at increased risk for cerebral embolism during CAS. Quantitative ultrasound plaque analysis, with ERI in particular, may add to clinical variables in identifying patients at risk for procedural stroke with CAS, but larger studies with clinical endpoints are needed.

Conventional magnetic resonance imaging in the differentiation between high and low-grade brain tumours in paediatric patients

ObjectiveIt has been described that hyperintensity in diffusion-weighted imaging (DWI) correlates with high-grade tumours, and high signal-intensity in T2-weighted (T2w) images identifies low-grade tumours. We aimed to investigate the potential of routine conventional MRI sequences, such as DWI and T2-w, to pre-operatively distinguish between low-grade and high-grade brain tumours in paediatric patients. Material and methodsTwo raters, blinded to the histological diagnosis, rated the aspect and signal intensity of MR images (T2w and DWI) from 37 children with newly diagnosed brain tumours. Histological diagnoses included 18 low-grade and 19 high-grade brain tumours. ResultsThe inter-rater agreement was 81–95%. High-grade tumours were never hypointense on DWI and low-grade tumours were usually hyperintense on T2w. Specificity was 100% for low-grade tumours and 90% for high-grade tumours. About 95% of the high-grade tumours and about 70% of the low-grade tumours were correctly diagnosed. ConclusionThe combination of general morphological aspect of the tumours and signals on T2-w and DWI yield a high accuracy of pre-operative differentiation between low-grade and high-grade paediatric tumours.

Reduction in Early Stroke Risk in Carotid Stenosis With Transient Ischemic Attack Associated With Statin Treatment

Statins reduce stroke risk when initiated months after transient ischemic attack (TIA)/stroke and reduce early vascular events in acute coronary syndromes, possibly via pleiotropic plaque stabilization. Few data exist on acute statin use in TIA. We aimed to determine whether statin pretreatment at TIA onset modified early stroke risk in carotid stenosis. We analyzed data from 2770 patients with TIA from 11 centers, 387 with ipsilateral carotid stenosis. ABCD2 score, abnormal diffusion weighted imaging, medication pretreatment, and early stroke were recorded. In patients with carotid stenosis, 7-day stroke risk was 8.3% (95% confidence interval [CI], 5.7-11.1) compared with 2.7% (CI, 2.0%-3.4%) without stenosis (P<0.0001; 90-day risks 17.8% and 5.7% [P<0.0001]). Among carotid stenosis patients, nonprocedural 7-day stroke risk was 3.8% (CI, 1.2%-9.7%) with statin treatment at TIA onset, compared with 13.2% (CI, 8.5%-19.8%) in those not statin pretreated (P=0.01; 90-day risks 8.9% versus 20.8% [P=0.01]). Statin pretreatment was associated with reduced stroke risk in patients with carotid stenosis (odds ratio for 90-day stroke, 0.37; CI, 0.17-0.82) but not nonstenosis patients (odds ratio, 1.3; CI, 0.8-2.24; P for interaction, 0.008). On multivariable logistic regression, the association remained after adjustment for ABCD2 score, smoking, antiplatelet treatment, recent TIA, and diffusion weighted imaging hyperintensity (adjusted P for interaction, 0.054). In acute symptomatic carotid stenosis, statin pretreatment was associated with reduced stroke risk, consistent with findings from randomized trials in acute coronary syndromes. These data support the hypothesis that statins started acutely after TIA symptom onset may also be beneficial to prevent early stroke. Randomized trials addressing this question are required.

Clinical outcomes of fast MRI-based trombolysis in wake-up strokes compared to superacute ischemic strokes within 12 hours

Background: It is unknown whether thrombolysis is beneficial in patients with Wake-Up Ischemic Strokes (WUIS). This study compares the clinical outcomes of MRI-based intravenous thrombolysis in patients with hyperacute ischemic stroke presenting within 12 hours of symptom onset against WUIS patients receiving the same therapy.Methods: Patients presenting within 12 hours of acute stroke symptom onset and those with WUIS confirmed by CT, and without intracranial hemorrhage, were encouraged to perform an emergent brain MRI scan to confirm the diagnosis of hyperacute ischemic stroke [hyper-intense in diffusion-weighted imaging (DWI) and no hypo-intense change in T2-weighted imaging (T2WI) or FLAIR]. These patients then received intravenous thrombolytic therapy with tissue-type plasminogen activator (rt-PA). All patients were divided into either stroke presenting within 12 hours or WUIS. The clinical outcomes were assessed by the modified Rankin Scale (mRS) and the Barthal Index (BI) at baseline and at 90 days after the thrombolysis therapy.Results: A total of 427 patients presenting with stroke like symptoms were given a MRI scan. Of these, 240 patients had confirmed diagnosis of hyperacute ischemic stroke (WUIS, n = 68, 68/116 = 58·62% versus within 12 hour, n = 172, 172/311 = 55·3%). Altogether, 186 patients (138 in within 12 hours group, and 48 in WUIS group) received intravenous thrombolytic therapy with rt-PA. No significant differences were found in clinical outcomes between the two groups at the baseline and at 90 days after the thrombolysis therapy. Also, no difference was found in the incidence rate of secondary hemorrhage (including both of asymptomatic and symptomatic) and mortality rate between the two groups.Conclusion: Our study suggested that MRI-based intravenous thrombolysis is safe and effective in both of patients’ hyperacute stroke within 12 hours of symptom onset and WUIS.

Diffusion‐Weighted imaging hyperintensities in intracerebral hemorrhage: Microinfarcts or microbleeds?

Annals of NeurologyVolume 73, Issue 6 p. 795-796 Letter Diffusion-Weighted imaging hyperintensities in intracerebral hemorrhage: Microinfarcts or microbleeds? Ashkan Shoamanesh MD, Ashkan Shoamanesh MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorLuciana Catanese MD, Luciana Catanese MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorOsamu Sakai MD, PhD, Osamu Sakai MD, PhD Departments of Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorAleksandra Pikula MD, Aleksandra Pikula MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorCarlos S. Kase MD, Carlos S. Kase MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this author Ashkan Shoamanesh MD, Ashkan Shoamanesh MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorLuciana Catanese MD, Luciana Catanese MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorOsamu Sakai MD, PhD, Osamu Sakai MD, PhD Departments of Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorAleksandra Pikula MD, Aleksandra Pikula MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this authorCarlos S. Kase MD, Carlos S. Kase MD Departments of Neurology and Radiology, Boston University Medical Center, Boston, MASearch for more papers by this author First published: 29 January 2013 https://doi.org/10.1002/ana.23853Citations: 12Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume73, Issue6June 2013Pages 795-796 RelatedInformation

Validation of diagnostic criteria using gadoxetic acid-enhanced and diffusion-weighted MR imaging for small hepatocellular carcinoma (≤ 2.0 cm) in patients with hepatitis-induced liver cirrhosis

Gadoxetic acid and diffusion-weighted imaging (DWI) is increasingly used for the diagnosis of hepatocellular carcinoma (HCC). It is relevant to refine the diagnostic parameters for HCC, using state-of-the-art imaging techniques. To validate usefulness of magnetic resonance imaging (MRI) criteria with gadoxetic acid-enhanced MRI and DWI for diagnosis of small HCC by differentiation from dysplastic nodule (DN) or regenerative nodule (RN) in cirrhotic patients with strongly suspected small HCC. One hundred and eight patients with 102 HCCs and 29 benign nodules including 21 DNs and two large RNs (≤ 2.0 cm), and 40 patients with no HCC underwent gadoxetic acid-enhanced MRI and DWI. All patients also underwent MDCT. Index MR criteria for HCC were: (i) arterial hyperenhancement and hypointensity on hepatobiliary phase (HBP) with hyperintensity on DWI; (ii) hypovascular nodule with hyperintensity on DWI; (iii) arterial hyperenhancement and hypointensity on HBP without hyperintensity on DWI; (iv) arterial hyperenhancement and either iso- or hyperintensity on HBP, with hyperintensity on DWI; and (v) hyperintensity only on DWI. According to these criteria, MRI findings for HCCs and benign nodules were independently classified by two reviewers. On multidetector-row computed tomography, 64 HCCs (62.7%) showed typical features for HCC while 13 (12.8%) were not identified. On MRI, 84 HCCs (82.4%) showed arterial hyperenhancement and hypointensity on HBP, and hyperintensity on DWI. Eight HCCs were regarded as hypovascular HCCs with hyperintensity DWI (category 2). One HCC (0.6 cm in diameter) was demonstrated only by DWI. For each observer, 101 (99.0%) and 100 HCCs (98.0%) were discernible when applying all MRI criteria for HCC, respectively. Three DNs also fit the HCC criteria, thus the specificity was 90.9% for both observers. With the HCC criteria based on combined gadoxetic acid-enhanced MRI and DWI, it is possible to reliably diagnose small HCC including hypovascular HCCs.

Complete Early Reversal of Diffusion-Weighted Imaging Hyperintensities After Ischemic Stroke Is Mainly Limited to Small Embolic Lesions

Case reports have demonstrated complete early reversal of hyperintensities on diffusion-weighted imaging (DWI) after clinically diagnosed stroke. We aimed to investigate systematically the rate and characteristics of reversible diffusion hyperintensities (RDHs) in the first week after stroke. Patients with clinical diagnosis of an acute cerebrovascular event and evidence of ischemia on DWI were included. MRI scans were performed on admission, on the following day, and 4 to 7 days after onset of symptoms with DWI and fluid-attenuated inversion recovery. Baseline and follow-up DWIs were coregistered and examined for individual RDHs. Characteristics of patients and of hyperintensities associated with early reversal were identified. We included 153 patients with a median National Institutes of Health Stroke Scale score of 4 (interquartile range, 2-8). In 3 patients (2%), MR images normalized completely. Thirty-seven patients (24%) displayed individual RDHs. Of 611 initial DWI hyperintensities, 97 (16%) reversed. Thirteen percent of the RDHs had corresponding abnormalities on fluid-attenuated inversion recovery images at the third measurement. Median size of the RDHs was 0.029 mL (interquartile range, 0.013-0.055). RDHs were associated with a multiple infarct pattern (odds ratio, 22.1; 95% confidence interval, 4.5-109.7) and symptomatic carotid stenosis (odds ratio, 5.5; 95% confidence interval, 1.4-21.5). Fifty-nine percent of the patients with RDHs had new additional lesions on follow-up DWI. RDHs were not associated with functional improvement on the National Institutes of Health Stroke Scale score. In this population of mainly minor to moderate stroke patients, complete normalization of MR images was rare. Complete reversal of individual DWI hyperintensities was limited to very small lesions and mostly occurred in embolic stroke patients. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00715533.

Preoperative Diffusion-Weighted Imaging of Single Brain Metastases Correlates with Patient Survival Times

BackgroundMRI-based diffusion-weighted imaging (DWI) visualizes the local differences in water diffusion in vivo. The prognostic value of DWI signal intensities on the source images and apparent diffusion coefficient (ADC) maps respectively has not yet been studied in brain metastases (BM).MethodsWe included into this retrospective analysis all patients operated for single BM at our institution between 2002 and 2010, in whom presurgical DWI and BM tissue samples were available. We recorded relevant clinical data, assessed DWI signal intensity and apparent diffusion coefficient (ADC) values and performed histopathological analysis of BM tissues. Statistical analyses including uni- and multivariate survival analyses were performed.Results65 patients (34 female, 31 male) with a median overall survival time (OS) of 15 months (range 0–99 months) were available for this study. 19 (29.2%) patients presented with hyper-, 3 (4.6%) with iso-, and 43 (66.2%) with hypointense DWI. ADCmean values could be determined in 32 (49.2%) patients, ranged from 456.4 to 1691.8*10−6 mm2/s (median 969.5) and showed a highly significant correlation with DWI signal intensity. DWI hyperintensity correlated significantly with high amount of interstitial reticulin deposition. In univariate analysis, patients with hyperintense DWI (5 months) and low ADCmean values (7 months) had significantly worse OS than patients with iso/hypointense DWI (16 months) and high ADCmean values (30 months), respectively. In multivariate survival analysis, high ADCmean values retained independent statistical significance.ConclusionsPreoperative DWI findings strongly and independently correlate with OS in patients operated for single BM and are related to interstitial fibrosis. Inclusion of DWI parameters into established risk stratification scores for BM patients should be considered.

Abstract WMP116: Incidental Diffusion-weighted Imaging Lesions In Patients With Cognitive Decline

Objectives: Incidental diffusion-weighted imaging (DWI) hyperintense lesions on MRI, indicative of incident silent infarcts, are not uncommon in patients with advanced cerebral small vessel disease (SVD). SVD has been increasingly recognized as playing an important role in cognitive decline in the elderly. We thus examined the prevalence and associated risk factors for DWI hyperintense lesions in a cohort of patients followed in a memory clinic. Methods: We retrospectively analyzed MRI scans from 251 patients (43% females, mean age 73.3±8.3) with cognitive impairment enrolled in an ongoing prospective longitudinal study at the Massachusetts Alzheimer’s Disease Research Center (MADRC) between 2001 and 2010. Clinical and demographic data including the presence of specific vascular risk factors and degree of cognitive impairment (as measured by the Clinical Dementia Rating (CDR) Scale) were recorded. DWI and apparent diffusion coefficient (ADC) images were inspected for the presence of DWI-hyperintense lesions. Associated MRI markers of SVD including white matter hyperintensities (WMH), whole-brain mean global ADC, cerebral microbleeds (CMB) and lacunar infarcts were quantified. Results: We identified 16 DWI-hyperintense lesions in 13 (5.2%) patients. The 14 individuals with at least one DWI lesion did not differ from the 237 without lesions by age, gender, vascular risk factors, CDR, moderate to severe WMH, mean global ADC or number of CMB (p&gt;0.05). Assuming a 10-day post-stroke period when DWI lesions remain hyperintense, their estimated annual prevalence would be 2.3 new infarcts per person-year. Conclusions: Incident DWI-hyperintense lesions, consistent with subacute cerebral infarcts, are not uncommon in unselected patients with cognitive decline. These lesions do not appear to be associated with other markers of SVD nor with degree of impairment. Our results suggest that the cumulative lifetime burden of these lesions may be substantial. These findings may support a role for small infarcts in age-related cognitive impairment.