RÉSUMÉ
Objective:To evaluate the correlation between vascular hyperintensity of magnetic resonance fluid-attenuated inversion recovery (FLAIR) sequence(FVH) and related parameters of magnetic resonance perfusion weighted imaging (MR-PWI) in patients with middle cerebral artery stenosis cerebral infarction, and to explore the hemodynamic factors related to FVH and the effect of FVH on the short-term clinical prognosis of patients.Methods:A total of 116 patients with middle cerebral artery stenosis cerebral infarction in the Department of Neurology, Qingpu Branch of Zhongshan Hospital Affiliated to Fudan University from January 2020 to December 2022 were collected.According to the diagnostic criteria of FVH, they were divided into FVH (+ ) group (78 cases) and FVH(-) group (38 cases). All patients underwent magnetic resonance(MR) and MR-PWI scans.Demographic and cerebrovascular risk factors were collected, clinical neurological function of patients was assessed by national institate of health stroke scale(NIHSS) upon admission and discharge, and cognitive function of patients was assessed by mini-mental state examination (MMSE). Short-term clinical outcome was assessed using modified Rankin scale(mRS) at the 90th day after discharge.The degree of middle cerebral artery stenosis, positive or negative FVH, FVH score, hypoperfusion volume and MR-PWI related parameters, including peak time (Tmax), mean transit time (MTT), cerebral blood volume (CBV) and cerebral blood flow (CBF), were evaluated in relation to clinical symptoms.SPSS 22.0 statistical software was used for t test, Chi-square test and Pearson correlation analysis. Results:There were significant differences in hypoperfusion volume, Tmax, MTT and CBF between FVH (+ ) group and FVH(-) group( t=1.989, 3.830, 5.223, 3.911, all P<0.05). In terms of short-term clinical outcome, the improvement rate of neurological function ((8.25±6.39)%, (12.22±6.08)%) and MMSE score(25.48±1.59), (26.31±1.26) in FVH (+ ) group were significantly lower than those in FVH(-) group, and the number of patients with progressive stroke during hospitalization in FVH(+ ) group was more than that of FVH(-) group(22(28.21%), 4(10.53%)) (all P<0.05). Pearson correlation analysis showed that FVH score was positively correlated with hypoperfusion volume ( r=0.786, P<0.01) and MTT ( r=0.692, P<0.01), and negatively correlated with CBF ( r=-0.568, P<0.01), but no significant correlation with the degree of arterial stenosis ( r=0.363, P>0.05). Conclusion:FVH is closely related to the Tmax, MTT and CBF values shown in MR-PWI, and the incidence of stroke in progression and short-term adverse prognosis are more likely in FVH(+ ) group, suggesting that FVH can be used as a convenient imaging indicator to reflect the hypoperfusion status of patients with middle cerebral artery stenosis cerebral infarction, and can provide an objective basis for further individualized treatment.
RÉSUMÉ
Objective:To investigate the predictive value of fluid-attenuated inversion recovery (FLAIR) signal strength ratio (SIR) in onset time≤4.5 h in patients with acute ischemic stroke.Methods:A retrospective analysis was performed; 180 acute ischemic stroke patients admitted to Department of Neurology, Nanjing Hospital Affiliated to Nanjing Medical University from January 2020 to June 2023 were chosen. Hypoperfusion intensity ratio (HIR) was used to evaluate the collateral circulation (poor collateral circulation: HIR≤0.4; good collateral circulation: HIR>0.4); clinical data and imaging indexes between poor collateral circulation and good collateral circulation groups were compared. Univariate and multivariate Logistic regressions were used to analyze the influencing factors for onset time≤4.5 h in patients with acute ischemic stroke. Correlation between SIR and onset time was analyzed in patients with acute ischemic stroke. Role of HIR as agency between SIR and onset time was explored. Receiver operating characteristic (ROC) curve was used to analyze the predictive efficacy of SIR and diffusion weighted imaging (DWI)-FLAIR mismatch in onset time≤4.5 h in acute ischemic stroke patients.Results:Of the 180 patients, 100 were into the good collateral circulation group and 80 were into the poor collateral circulation group; compared with the good collateral circulation group, the poor collateral circulation group had significantly higher percentage of patients with hyperlipidemia, larger DWI infarction volume before treatment, larger perfusion weighted imaging (PWI)-DWI mismatch volume and higher SIR ( P<0.05). In these 180 patients, 76 had onset time≤4.5 h and 104 had onset time>4.5 h. Univariate Logistic regression analysis showed that hyperlipidemia, DWI infarct volume before treatment, DWI-FLAIR mismatch, HIR and SIR were influencing factors for onset time≤4.5 h in acute ischemic stroke patients ( P<0.05). Multivariate Logistic regression analysis showed that hyperlipidemia ( OR=6.654, 95% CI: 5.751-8.824, P<0.001), HIR ( OR=0.724, 95% CI: 0.521-1.321, P=0.041) and SIR ( OR=739.881, 95% CI: 383.296-14 258.065, P<0.001) were independent influencing factors for onset time≤4.5 h in acute ischemic stroke patients. Pearson correlation analysis showed that SIR was positively correlated to onset time in patients with acute ischemic stroke ( r=0.420, P<0.05), and SIR was positively correlated to onset time in patients from poor collateral circulation group ( r=0.781, P<0.05). ROC curve showed that AUC of SIR in predicting onset time≤4.5 h was 0.917 (95% CI: 0.814-1.000, P<0.001) and that of DWI-FLAIR mismatch in predicting onset time≤4.5 h was 0.530 (95% CI: 0.509-0.757, P=0.075) in poor collateral circulation group, enjoying significant difference in predictive efficacy. Conclusion:Acute ischemic stroke patients with low HIR and SIR have higher odds of onset time≤4.5 h; SIR can more accurately predict the onset time in these patients with poor collateral circulation.
RÉSUMÉ
Context: Patients with metallic dental objects in their oral cavity are often associated with discomfort or artefacts during magnetic resonance imaging (MRI) of the head and neck. Aim: This study was conducted to evaluate the effects of metallic dental objects in causing patient discomfort and artefacts during MRI of the head and neck region. Design: This is an observational study including 538 participants from various specialized MRI centres in Kozhikode. Methods and Material: MRI records of 538 participants who underwent head and neck MRI as a part of their medical treatment were collected. With the help of questionnaire and clinical examination, the type of metallic dental object in the patient’s oral cavity was identified. After examining the MRI images, four categories of artefacts were established. In MRI brain, artefacts in three different sequences were also studied. Statistical Analysis Used: The significance of the difference between proportions was analysed by the Chi?square test. Results: Artefacts were found in 65 cases with metallic dental objects but none of the participants had experienced any kind of discomfort. The artefact formation significantly depended on the type of metallic dental restoration in the patient’s oral cavity. Orthodontic braces and titanium bone plate created severe artefacts in head and neck MRI making interpretation almost impossible. In the MRI brain, diffusion?weighted imaging is most sensitive to artefact followed by fluid?attenuated inversion recovery. Conclusions: Artefacts were found in 65 cases with metallic dental restorations but none of the participants had experienced any kind of discomfort.
RÉSUMÉ
Background: At present, the diagnosis and efficacy evaluation of acute leukemia (AL) are assessed by bone marrow aspiration, which is invasive and subject to sampling errors. Therefore, there is a pressing need to develop a noninvasive and accurate imaging method to evaluate bone marrow changes in patients with AL. This study aimed to compare the apparent diffusion coefficient (ADC) values obtained from fluid?attenuated inversion recovery diffusion?weighted imaging (FLAIR?DWI) and conventional DWI in the lumbar bone marrow of patients with AL and to investigate their performance for evaluating response to induction chemotherapy. Methods: A total of 28 patients with newly diagnosed AL and 25 patients with AL after induction chemotherapy underwent MRI scans at 1.5 Tesla using a conventional DWI and a FLAIR?DWI sequence on sagittal planes covering the lumbar bone marrow. Further, the ADC values from these two sequences, denoted as ADCCON and ADCFLAIR, were measured on multiple vertebrae. The percentage of leukemia cells in bone marrow was recorded, and bone marrow aspiration was performed on treated patients to determine complete remission (CR) and nonremission (NR). Results: ADCFLAIR [(0.453 ± 0.103) × 10?3 mm2/s] was significantly lower than ADCCON [(0.486 ± 0.096) × 10?3 mm2/s] in the 28 untreated patients (t = 3.051, P = 0.005). In the 25 treated patients, ADCFLAIR and ADCCON values [(0.566 ± 0.239) × 10?3 mm2/s] and [(0.716 ± 0.235) × 10?3 mm2/s], respectively, were higher compared with the untreated patients. The ADCCON values showed a nonsignificant difference between the CR (n = 18) and NR (n = 7) groups (t = 1.409, P = 0.305). However, the ADCFLAIR values exhibited statistically significant difference (t = 2.542, P = 0.018) between the two groups. In a receiver operator characteristic (ROC) analysis, the area under the curve (AUC) using ADCFLAIR (0.770) was larger than that of ADCCON (0.611) in distinguishing the CR and NR patients following the chemotherapy. Conclusion: Although both ADCCON and ADCFLAIR are sensitive to tissue changes induced by chemotherapy, FLAIR?DWI outperformed conventional DWI in separating AL patients with CR from NR after chemotherapy. A possible mechanism is that FLAIR?DWI suppresses signals from free water, making the ADC measurement more sensitive to structural changes in the bone marrow
RÉSUMÉ
@#Introduction: Intravenous thrombolysis (IVT) is the gold standard for the treatment of patients with acute ischemic stroke (AIS) presenting within four and a half hours of onset. However, development of new thrombolytic agents and advanced imaging has led to extended time for thrombolysis based on advanced imaging. Here we describe four patients who presented in the extended hours; that benefitted from thrombolysis. Case series: We advocate magnetic resonance imaging (MRI) for AIS, that includes diffusion weighted imaging (DWI), apparent diffusion coefficient (ADC), fluid attenuated inversion recovery (FLAIR), susceptibility weighted imaging (SWI), and magnetic resonance angiography (MRA). We included four patients who were more than 18 years old, with National Institute of Health Stroke Scale (NIHSS) of six or more, presenting between four and a half to nine hours after stroke onset with no contraindications for intravenous thrombolysis. The imaging criteria used to determine eligibility for IVT is evidence of DWI-FLAIR mismatch on MRI. If FLAIR detects no signal change in the area of stroke on DWI, it is then termed DWIFLAIR mismatch, or FLAIR-negative – indicating high probability that the brain tissue is still viable, and that patients are good candidates for IVT. Conclusion: For patients with AIS who present within nine hours, DWI-FLAIR mismatch serves as an excellent surrogate marker of salvageable brain tissue, allowing a greater proportion of patients benefiting from this life-saving therapy. Our experience also shows that with careful patient selection, treatment with IVT can safely be given without an increased risk of bleeding or mortality.
RÉSUMÉ
Objective:To evaluate the effect of deep learning based on DWI and fluid attenuated inversion recovery (FLAIR) to construct a prediction model of the onset time in acute stroke.Methods:A total of 324 cases of acute stroke with clear onset time, from January 2017 to May 2020 in Nanjing First Hospital, were retrospectively enrolled and analyzed. The patients were divided into a training set of 226 patients and a test set of 98 patients according to the complete randomization method using a 7∶3 ratio, and the patients were divided into ≤ 4.5 h and >4.5 h according to symptom onset time in each group. The acute infarction areas on DWI and the corresponding high signal area on FLAIR were manually outlined by physician. Using the InceptionV3 model as the basic model for image features extraction, the deep learning prediction model based on single sequence (DWI, FLAIR) and multi sequences (DWI+FLAIR) were established and verified. Then the area under curve (AUC), accuracy of human readings, single sequence model and multi sequence model in predicting the acute stroke onset time from imaging were compared.Results:DWI-FLAIR mismatch was found in 94 cases (94/207) of patients with symptom onset time from imaging ≤ 4.5 h, while in 28 cases (28/117) of patients with symptom onset time from imaging >4.5 h. ROC analysis showed that the AUC of DWI-FLAIR mismatch in predicting acute stroke onset time from imaging was 0.607, and the accuracy was 60.2%. The prediction model of deep learning based on single sequence showed that the AUC of FLAIR was 0.761 and the accuracy was 71.4%; the AUC of DWI was 0.836 and the accuracy was 81.6%. The AUC of predicting stroke onset time based on the multi-sequence (DWI+FLAIR) deep learning model was 0.852, which was significantly better than that of manual identification ( Z = 0.617, P = 0.002), FLAIR sequence deep learning model ( Z = 2.133, P = 0.006) and DWI sequence deep learning model ( Z = 1.846, P = 0.012). Conclusion:The deep learning model based on DWI and FLAIR is superior to human readings in predicting acute stroke onset time from imaging, which could provide guidance for intravenous thrombolytic therapy for acute stroke patients with unknown onset time.
RÉSUMÉ
Fluid Attenuated Inversion Recovery (FLAIR) MRI of brain is sensitive in detecting parenchymal lesions, extra axial lesions such as meningoencephalitis, and leptomeningeal tumoural disease. We wanted to compare gadolinium enhanced T2W FLAIR with PC-T1W (post contrast T1 weighted) MRI sequence in detection and evaluation of meningeal and parenchymal lesions. We also wanted to compare gadolinium enhanced T1W FLAIR with PC-T1W MRI sequence in detection and evaluation of meningeal and parenchymal lesions.METHODS65 patients with clinical diagnosis of cerebral meningitis or intracranial tumoural disease were scanned on 1.5 T 16 channel MRI scanner. A standard brain protocol was used, followed by PC-T1W and post contrast FLAIR, with PC-T1W MR preceding post contrast FLAIR. Images were assessed independently by 2 radiologists who marked the technique they thought had made the meningeal and parenchymal disease more conspicuous. In case of disagreement the radiologists made a consensus determination.RESULTSPC-T2 FLAIR showed better enhancement in 100% of the intra axial lesions compared to PC-T1W images. However, PC-T1 FLAIR showed better enhancement than PC-T1W images in only 81% of the same. PC-T2 FLAIR showed better enhancement in 100% of the extra-axial lesions compared to PC-T1W images. However, PC-T1 FLAIR showed less enhancement in all the extra axial lesions.CONCLUSIONSContrast enhanced T2 FLAIR MRI showed better enhancement of parenchymal and meningeal lesions. PC-T2 FLAIR detected more number of lesions when compared to PC-T1W, aided better delineation of extra-axial mass lesions due to superior enhancement, and had a better demarcated dural tail. Post-contrast T2 FLAIR images should be included in routine protocol for contrast MRI brain study.
RÉSUMÉ
Objective:To explore the relation between extended resection and prognosis of primary glioblastoma.Methods:A prospective study was performed. The subjects were from the colony of patients with primary glioblastoma who underwent surgical resection in our hospital from January 2014 from January 2017. Tumor volume and tumor residual volume showed by MR imaging T1 enhanced sequences (Group A and Group B), and tumor volume and tumor residual volume showed by fluid-attenuated inversion recovery (FLAIR) sequences (Group A1 and Group A2) were obtained within one week before surgery and 24 h after surgery, respectively; and the degrees of tumor resection were calculated. Cox proportional hazards regression model was used to determine factors influencing overall survival (OS) in glioblastoma patients. Kaplan-Meier method was used to plot the survival curves of these patients. Log-rank test was used to compare the survival rates of patients from Group A and Group B, and patients from Group A1 and Group A2.Results:A total of 128 patients were included; 71(55.5%) were into Group A, and 17 (13.3%) were into Group A1. Multivariate analysis showed that preoperative Karnofsky performance scale (KPS) scores, promoter methylation status of O-6-methylguanine-DNA methyltransferase (MGMT), tumor residual volume by T1 enhanced sequences, tumor residual volume by FLAIR sequences, and tumor resection degree by FLAIR sequences were independent influencing factors for OS ( P<0.05). Survival rate of patients from Group A was significantly higher than that in Group B( P<0.05); and survival rate of patients from Group A1 was significantly higher than that in Group A2 ( P<0.05). Conclusion:Residual of primary glioblastoma showed by FLAIR sequences is an important factor affecting the prognoses, and extended resection is necessary.
RÉSUMÉ
Objective To explore the limits of fluid-inversion prepared diffusion weighted imaging (FLIPD) in detection of acute cerebral ischemic lesions.Methods From January 2012 to March 2014,forty-nine patients (33 males,16 females,age (55.6± 12.3) years) clinically diagnosed as transient ischemic attack (TIA) were included.Patients underwent brain MRI (conventional diffusion weighted imaging (DWI) and FLIPD) within 3 d after the onset of TIA.The detection ability of MRI with the two sequences was compared,and the relative signal intensity (rSI) and apparent diffusion coefficient (ADC) of acute ischemic lesions based on two sequences were compared.Kappa test and two-sample t test were used to analyze the data.Results A total of 87 acute ischemic lesions were detected in 21 patients by conventional DWI,and 54 were detected in 19 patients by FLIPD (Kappa=0.916,P＜0.05).The rSI of ischemic lesions on FLIPD was significantly lower than that on conventional DWI (1.37±0.22 vs 1.57±0.26;t=6.647,P＜0.001).The ADC value of ischemic lesions on FLIPD was slightly lower than that on conventional DWI:(0.54 ±0.10) ×10-3 mm2/s vs (0.57±0.13)×10-3 mm2/s (t=2.120,P＜0.05).The missed lesions on FLIPD were located in the white matter (n =18),cerebellum and brainstem (n =8),and the cortex (n =7).Conclusions A slight diffuse abnormality may be missed on FLIPD,so this method is not suitable for the detection of acute ischemic lesions.FLIPD technology still needs improvement.
RÉSUMÉ
Objective To investigate the relationship between the ratio of signal intensity of fluid-attenuated inversion recovery (FLAIR)sequence lesion side／contralateral side and the onset time of acute ischemic stroke. Methods Forty-three consecutive patients with acute ischemic stroke admitted to the Department of Neurology,Dongguan Hospital of Traditional Chinese Medicine from November 2016 to January 2018 were enrolled retrospectively. They were all first onset and were diagnosed by MRI,and the onset time was 0. 5 to 6. 0 h. According to the time window of effective rescue of the penumbra,43 patients were divided into a ≤4. 5 h group (n＝19)and a ＞4. 5-6. 0 h group (n＝24). The signal intensity values of FLAIR, diffusion-weighted imaging,signal intensity of apparent diffusion coefficient sequence on the lesion side and contralateral brain tissue in the two groups of patients were measured respectively,and the relative signal intensity (RSI)was calculated and compared between the two groups. Taking RSI as the dependent variable and onset time as the independent variable,a general linear regression analysis was performed. Results (1)In FLAIR sequence,the signal intensity value and RSI value of patients in the≤4. 5 h group were lower than those in the ＞4. 5-6. 0 h group. There were significant differences between the 2 groups (disease side signal intensity value:531 ± 109 vs. 681 ± 306,t ＝2. 04;RSI value:1. 19 ± 0. 13 vs. 1. 45 ± 0. 18,t＝5. 29,all P＜0. 05). There was no significant difference in the signal intensity values on the contralateral sides between the two groups (P＞0. 05). (2)In diffusion weighted imaging and apparent diffusion coefficient sequence,there were no significant differences in the signal intensity value and RSI value on the disease side and the contralateral side between the the≤4. 5 hours group and the ＞4. 5-6. 0 h group (all P＞0. 05). (3)In the FLAIR sequence,with the prolongation of the time of the disease,RSI gradually increased,and was positively correlated (r＝0. 756,P＜0. 01). Conclusions The quantitative measurement of the disease side／contralateral side of FLAIR sequence might reflect the onset time of acute ischemic stroke. Its RSI value increased with the prolonged onset time.
RÉSUMÉ
Objective To investigate the correlation between white matter hyperintensities (WMH)and hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging(MRI)in old adults and to explore the risk factors and pathogeneses of WMH.Methods We retrospectively collected imaging and clinical data of patients who had received both head and neck CTA and brain MRI within one month at our hospital from 2013 to 2016.The Fazekas visual scale was used to evaluate periventricular white matter hyperintensity(PWMH)and deep white matter hyperintensity(DWMH)in each brain hemisphere.According to the presence or absence of HVS in a cerebra[hemisphere,patients were assigned into an HVS-positive group or an HVS-negative group.Clinical data,PWMH,and DWMH differences were compared between the two groups.Results A total of 271 patients(542 cerebral hemispheres)were included in this study.HVS-positive imaging occurred in 79(14.6％)cerebral hemispheres and negative imaging was observed in 463 (85.4％) cerebral hemispheres.There was a significant difference between the HVS-positive and negative groups in the ipsilateral CIA stenosis(x2 =126.840,P＜0.01).The incidence of ipsilateral severe carotid artery stenosis in the HVS-positive group was 62.0％ (49/79),which was significantly higher than 9.9％ (46/463)in the HVS-negative group.The incidence of moderate-severe DWMH was 65.8％(52/79) in the HVS-positive group,which was higher than 34.8％ (161/463)in the negative group(x2 =34.962,P ＜20.01).Nevertheless,the incidences of moderate-severe PWMH in the two groups were 65.8％ (52/79) and 55.5％ (257/463),respectively,without a significant difference between them (x2 =6.944,P =0.074).After adjusting for age,gender,ipsilateral ICA stenosis,hypertension,diabetes,etc.multivariate analysis suggested that HVS-positive imaging was still an independent risk factor for DWMH(OR =2.653,95％CI:1.489-4.726,P =0.001).Conclusions HVS-positive imaging is an independent risk factor for DWMH in the elderly,but no clear correlation with PWMH is found.It suggests that hypoperfusion is a possible mechanism for the development of DWMH in the elderly.
RÉSUMÉ
Objective: To assess fluid-attenuated inversion recovery (FLAIR) vascular hyper-intensity (FVH) and explore its relationship with CT perfusion (CTP) penumbral/infarct core mismatch ratio and diffusion weighted imaging (DWI) final infarct volume in acute ischemic stroke (AIS) patients with middle cerebral artery occlusion (MCAO). Methods: The CTP and MRI images of 38 AIS patients with MCAO were reviewed. The FVH score (longitudinal direction) [FVH score (L)] and FVH score (transverse direction) [FVH score (T)] were quantified on the FLAIR images. The FVH score (L) (range, 0-16) was based on a rostrocaudal extension of FVH and the FVH score (T) (range, 0-3) was based on FVH supply of the occluded MCA territory. The mismatch ratio was calculated from the ratio of the [mean transit time - cerebral blood volume (CBV)] lesion/CBV lesion on the CTP images. The DWI infarct volume was measured on the DWI images. Results: The mismatch ratio was larger for the group of FVH score (L)=7~8 than those of FVH score (L)=5~6 and FVH score (L)=3~4 (p=0.03), whereas the DWI infarct volume was smaller (p=0.04). Similarly, the mismatch ratio of FVH score (T)=2~3 group was larger than FVH score (T)=1 group (p=0.01), whereas the DWI infarct volume was smaller (p=0.02). Both FVH score (L) and FVH score (T) correlated positively with mismatch ratio (P=0.02, P=0.001, respectively), but negatively with DWI infarct volume (P=0.03, P=0.004, respectively). Conclusions: Higher FVH score is associated with larger mismatch ratio and smaller DWI infarct volume in AIS patients with MCAO. FLAIR vascular hyperintensity may represent collateral arterial circulation, and may play a role in protecting the ischemic penumbra.
Sujet(s)
Infarctus du territoire de l'artère cérébrale moyenneRÉSUMÉ
Objective To explore the impact of MR imaging T2 fluid-attenuated inversion-recovery sequence (MRI T2Flair) excision extension and postoperative chemotherapy in prognosis of patients with glioblastoma (GBM). Methods A retrospective study of clinical data and treatment efficacy of 17 patients with GBM, admitted to our hospital from April 2012 to August 2016, was performed. All patients were performed tumor resection by using awake anesthesia, neuroimage navigation, and intraoperative direct electrical stimulation. The impacts of the resection extent of T2Flair lesions and adjuvant chemotherapy on the prognosis of glioblastoma were analyzed. Results T1 enhanced lesions in these 17 patients were totally resected. The median follow-up duration was 18 months (8 months to 52 months). Median survival time was 20 months; the survival time of patients with resection ranges of 0%-10%, 10%-25% and more than 25% were 19, 22 and 24 months, respectively, without statistical differences (P>0.05). The patients adopted less than 6 courses chemotherapy had a 19-month-long median survival time, and those adopted 6 courses or more courses chemotherapy had a 33-month-long median survival time, with statistically significant difference (P<0.05). Conclusion When T1 enhanced lesions are totally resected, the resection extent of T2Flair lesions has no influence on patients survival time; however, patients accepted 6 or more courses of chemotherapy have a better survival.
RÉSUMÉ
Objective To analyze the risk factors of cortical micro-infarcts (CMIs) in patients with acute ischemic stroke and to evaluate the diagnostic value of 3.0 Tesla (T) magnetic resonance imaging (MRI) using double inversion recovery (DIR) sequence and 3-dimensional fluid attenuated inversion recovery (3D-FLAIR) sequence in CMIs in vivo.Methods One hundred and ten consecutive patients with acute ischemic stroke within 7 d of onset were chosen from August 2014 to July 2015;these patients were classified into CMIs group and non-CMIs group by results of 3.0 conventional T MRI,DIR-MRI and 3D-FLAIR-MRI.Baseline characteristics and risk factors were analyzed to investigate the independent risk factors of CMIs.The presence of CMIs was evaluated based on conventional T MRI,DIR-MRI and 3D-FLAIR-MRI.Results Of the 110 enrolled patients with acute ischemic stroke,CMIs were presented in 23.6％ patients (26/110).The age of patients from the CMIs group was significantly older as compared with that of patients from the non-CMIs group (67.65±10.37 vs.58.52± 11.24 years old,P=0.009).Patients from the CMIs group had significantly higher percentages of age＞65 years,age of 76-80 years,hypertension,history of cerebral ischemia and intracranial atherosclerosis than patients from non-CMIs group (P＜0.05).Multivariate Logistic regression analysis indicated that age＞65 years (OR=1.982;95％CI:1.362-2.889,P=0.010) and hypertension (OR=1.326;95％CI:1.022-1.682,P=0.026) were the independent risk factors of CMIs.The prevalence of CMIs detected by conventional sequence (10.9％) was significantly lower than that detected by DIR sequence (23.6％) or 3D-FLAIR sequence (20.9％,P=0.013 and P=0.043).Conclusions Age＞65 years and hypertension are independent risk factors of CMIs.DIR and 3D-FLAIR sequences at 3.0 T MRI substantially improve the sensitivity of detection of CMIs as compared with conventional MRI sequence.
RÉSUMÉ
Objective To investigate the significance of MRI T2 fluid-attenuated inversion recovery hyperintense vessel sign (FLAIR HVS)in clinical prognosis evaluation of the patients with acute middle cerebral artery irnfarction.Methods The data in 57 inpatients with acute middle cerebral artery infarction in our hospital from Aug.2013 to Aug.2015 were retrospectively analyzed.All cases were performed the intact MRI examination(ineluding FLAIR,DWI and MRA)and CTA.The infarct volume with DWI,national institute of health stroke scale(NIHSS)score and modified Rankin Scale(mRS)score on 30 d after discharge were performed the comparative analysis.Results Fifty-seven cases of middle cerebral artery occlusion were divided into the distal HVSgroup and non-distal HVS group(8 cases in proximal HVS group,21 cases in HVS negative group).The infarction volume of DWI sequence,NIHSS scores at admissiom and discharge and mRS score on 30 d after discharge in the distal HVS group were superior to those in the non-distal HVS group(P＜0.05).Conclusion MRI-T2 FLAIR sequence HVS has certain reference value in the prognosis evaluation in the patients with middle cerebral artery occlusion.
RÉSUMÉ
Objective To explore the value of fluid-attenuated inversion recovery (FLAIR)sequence and gradient echo T2 ?weighted image (GRE-T2 ? WI)in diagnosis of acute traumatic extra-axial hemorrhage.Methods 50 patients who were diagnosed as acute traumatic extra-axial hemorrhage by plain CT underwent FLAIR and GRE-T2 ? WI in acute stage.The diagnosis consistency (Kappa ),detection rate of subarachnoid hemorrhage(SAH),epidural hemorrhage(EDH)and subdural hemorrhage(SDH)were compared.The detection rates of SAH in 8 locations among FLAIR,GRE-T2 ? WI and combination of two sequences were analyzed by Chi-square test.Results 48 patients were enrolled in the study.The diagnosis consistency of SAH between FLAIR and GRE-T2 ? WI was high (k =1.0).The detection rate of SAH was 100% for both FLAIR and GRE-T2 ? WI.Comparing with GRE-T2 ? WI and combi-nation of two sequences,FLAIR tended to misdiagnose SAH in perimesencephalic cistern (P <0.05).The diagnosis consistency of EDH between FLAIR and GRE-T2 ? WI was high (k =1.0).3 patients with EDH were all detected by FLAIR and GRE-T2 ? WI. The diagnosis consistency of SDH between FLAIR and GRE-T2 ? WI was high (k =0.943).The detection rate of 12 patients with SDH was 100% in FLAIR,and 1 patient with SDH was missed by GRE-T2 ? WI.Conclusion The detection rate of acute traumatic extra-axial hemorrhage is high for both FLAIR and GRE-T2 ? WI.Combination of two sequences can improve the accuracy of acute traumatic extra-axial hemorrhage in clinic.
RÉSUMÉ
PURPOSE: Fluid-attenuated inversion recovery (FLAIR) imaging can be obtained faster with shorter repletion time (TR), but it gets noisier. We hypothesized that shorter-TR FLAIR obtained at 3 tesla (3T) with a 32-channel coil may be comparable to conventional FLAIR. The aim of this study was to compare the diagnostic value between conventional FLAIR (TR = 9000 ms, FLAIR9000) and shorter-TR FLAIR (TR = 6000 ms, FLAIR6000) at 3T in terms of diffusion-weighted imaging-FLAIR mismatch. MATERIALS AND METHODS: We recruited 184 patients with acute ischemic stroke (28 patients 0.05). Interobserver agreement was excellent for both DWI-FLAIR9000 and DWI-FLAIR6000 (k = 0.904 and 0.883, respectively). Between the two FLAIR imaging sets, there was no significant difference of signal intensity ratio (mean, standard deviation; 1.25 ± 0.20; 1.24 ± 0.20, respectively) (P > 0.05). CONCLUSION: For the determination of mismatch or match between DWI and FLAIR imaging, there is no significant difference between FLAIR9000 and FLAIR6000 at 3T with a 32-channel coil.
Sujet(s)
Humains , Imagerie par résonance magnétique , Accident vasculaire cérébralRÉSUMÉ
Intracranial lesions may show contrast enhancement through various mechanisms that are closely associated with the disease process. The preferred magnetic resonance sequence in contrast imaging is T1-weighted imaging (T1WI) at most institutions. However, lesion enhancement is occasionally inconspicuous on T1WI. Although fluid-attenuated inversion recovery (FLAIR) sequences are commonly considered as T2-weighted imaging with dark cerebrospinal fluid, they also show mild T1-weighted contrast, which is responsible for the contrast enhancement. For several years, FLAIR imaging has been successfully incorporated as a routine sequence at our institution for contrast-enhanced (CE) brain imaging in detecting various intracranial diseases. In this pictorial essay, we describe and illustrate the diagnostic importance of CE-FLAIR imaging in various intracranial pathologic conditions.
Sujet(s)
Humains , Kystes arachnoïdiens/diagnostic , Encéphale/anatomopathologie , Tumeurs du cerveau/diagnostic , Produits de contraste , Imagerie par résonance magnétique/méthodesRÉSUMÉ
Objective To investigate the application of magnetic resonance imaging (MRI) fluid-attenuated inversion recovery vascular hyperintensities (FVH) for the diagnosis of transient ischemic attack (TIA). Methods Consecutive 218 inpatients for TIA from May 2011 to July 2013 were reviewed with gender, age, cardiovascular risk factors, TIA or a history of stroke, TIA duration, and calculate the ABCD2 scores. All patients accepted MRI and MRA within 24 hours of symptom onset. FVH positive patients would follow up MRI and MRA with-in 7 days. All the patients were followed up in 90 days. Results FVH was identified in 45 patients (21%), 15 cases of them was found diffu-sion weighted imaging (DWI) hyperintensities on the same sides. The prevalence of atrial fibrillation (AF, P<0.001), DWI positive (P=0.010) and arterial occlusive lesions (AOL, P=0.003) were more in the FVH positive patients than in the negative ones, while the duration of symptoms was shorter (P=0.010). Multivariate Logistic regression analysis showed that AF (OR=7.17, 95%CI:2.71-18.4), AOL (OR=4.93, 95%CI:3.53-12.6) and hemiplegic (OR=2.84, 95%CI:1.21-7.42) independently associated with FVH. 7 days after the onset, FVH was not found in 15 patients (65%, transient FVH), in whom the prevalence of AF was more (P=0.020), and AOL was less (P<0.001). A total of 197 patients (90%) were successfully followed up. In the FVH-positive patients, 5 cases developed into recurrent TIA and 6 into ischemic stroke (IS), focused on the the same sides of FVH;while the FVH-negative patients, 2 cases developed into recurrent TIA and 5 into IS. COX pro-portional hazard analysis showed that FVH (HR=3.64, 95%CI:1.08-12.6) and AOL (HR=3.82, 95%CI:1.07-15.8) independently associat-ed with the recurrence of TIA or IS. Conclusion FVH can be helpful for the diagnosis of TIA and predictions for recurrent TIA or IS after a TIA.
RÉSUMÉ
@#Objective To investigate the application of magnetic resonance imaging (MRI) fluid-attenuated inversion recovery vascular hyperintensities (FVH) for the diagnosis of transient ischemic attack (TIA). Methods Consecutive 218 inpatients for TIA from May 2011 to July 2013 were reviewed with gender, age, cardiovascular risk factors, TIA or a history of stroke, TIA duration, and calculate the ABCD2 scores. All patients accepted MRI and MRA within 24 hours of symptom onset. FVH positive patients would follow up MRI and MRA within 7 days. All the patients were followed up in 90 days. Results FVH was identified in 45 patients (21%), 15 cases of them was found diffusion weighted imaging (DWI) hyperintensities on the same sides. The prevalence of atrial fibrillation (AF, P<0.001), DWI positive (P= 0.010) and arterial occlusive lesions (AOL, P=0.003) were more in the FVH positive patients than in the negative ones, while the duration of symptoms was shorter (P=0.010). Multivariate Logistic regression analysis showed that AF (OR=7.17, 95% CI: 2.71-18.4), AOL (OR=4.93, 95% CI: 3.53-12.6) and hemiplegic (OR=2.84, 95% CI: 1.21-7.42) independently associated with FVH. 7 days after the onset, FVH was not found in 15 patients (65%, transient FVH), in whom the prevalence of AF was more (P=0.020), and AOL was less (P<0.001). A total of 197 patients (90%) were successfully followed up. In the FVH-positive patients, 5 cases developed into recurrent TIA and 6 into ischemic stroke (IS), focused on the the same sides of FVH; while the FVH-negative patients, 2 cases developed into recurrent TIA and 5 into IS. COX proportional hazard analysis showed that FVH (HR=3.64, 95% CI: 1.08-12.6) and AOL (HR=3.82, 95% CI: 1.07-15.8) independently associated with the recurrence of TIA or IS. Conclusion FVH can be helpful for the diagnosis of TIA and predictions for recurrent TIA or IS after a TIA.