Fluid?attenuated inversion recovery diffusion?weighted imaging (DWI) for evaluating chemotherapy response in patients with acute leukemia: Comparison with conventional DWI

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

Tissue Window versus Time Window? A Review of Patients Receiving Extended Hours Thrombolysis Guided By DWI-FLAIR Mismatch : Case Series

@#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.

Comparison of Flair MRI to Contrast Enhanced T1W MRI in Selected Intracranial Pathologies for a Patient Population in North Kerala, India,

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.

Increased Signal in the Superior Cerebellar Peduncle of Patients with Progressive Supranuclear Palsy

OBJECTIVE: The provisional diagnosis of progressive supranuclear palsy (PSP) depends on a combination of typical clinical features and specific MRI findings, such as atrophy of the tegmentum in the midbrain. Atrophy of the superior cerebellar peduncle (SCP) distinguishes PSP from other types of parkinsonism. Histological factors affect the conventional fluid-attenuated inversion recovery (FLAIR) signals, such as the extent of neuronal loss and gliosis. METHODS: We investigated patients with PSP to verify the percentage of patients with various PSP phenotypes presenting a high signal intensity in the SCP. Three interviewers, who were not informed about the clinical data, visually inspected the presence or absence of a high signal intensity in the SCP on the FLAIR images. We measured the pixel value in the SCP of each patient. Clinical characteristics were evaluated using the Mann-Whitney test, followed by the χ² test. RESULTS: Ten of the 51 patients with PSP showed a high signal intensity in the SCP on FLAIR MRI. Higher pixel values were observed within the SCP of patients with a high signal intensity in the SCP than in patients without a high signal intensity (p < 0.001). The sensitivity and specificity of the high signal intensity in the SCP of patients with PSP was 19.6% and 100%, respectively. This finding was more frequently observed in patients with PSP with Richardson's syndrome (PSP-RS) (25.7%) than other phenotypes (6.2%). CONCLUSION: The high signal intensity in the SCP on FLAIR MRI might be an effective diagnostic tool for PSP-RS.

Comparison of Contrast-Enhanced T2 FLAIR and 3D T1 Black-Blood Fast Spin-Echo for Detection of Leptomeningeal Metastases

PURPOSE: Imaging plays a significant role in diagnosing leptomeningeal metastases. However, the most appropriate sequence for the detection of leptomeningeal metastases has yet to be determined. This study compares the efficacies of contrast-enhanced T2 fluid attenuated inversion recovery (FLAIR) and contrast-enhanced 3D T1 black-blood fast spin echo (FSE) imaging for the detection of leptomeningeal metastases. MATERIALS AND METHODS: Tube phantoms containing varying concentrations of gadobutrol solution were scanned using T2 FLAIR and 3D T1 black-blood FSE. Additionally, 30 patients with leptomeningeal metastases were retrospectively evaluated to compare conspicuous lesions and the extent of leptomeningeal metastases detected by T2 FLAIR and 3D T1 black-blood FSE. RESULTS: The signal intensities of low-concentration gadobutrol solutions (< 0.5 mmol/L) on T2 FLAIR images were higher than in 3D T1 black-blood FSE. The T2 FLAIR sequences exhibited significantly greater visual conspicuity scores than the 3D T1 black-blood sequence in leptomeningeal metastases of the pial membrane of cistern (P = 0.014). T2 FLAIR images exhibited a greater or equal extent (96.7%) of leptomeningeal metastases than 3D T1 black-blood FSE images. CONCLUSION: Because of its high sensitivity even at low gadolinium concentrations, contrast-enhanced T2 FLAIR images delineated leptomeningeal metastases in a wider territory than 3D T1 black-blood FSE.

Qualitative and Quantitative Comparison of Contrast-Enhanced Fluid-Attenuated Inversion Recovery, Magnetization Transfer Spin Echo, and Fat-Saturation T1-Weighted Sequences in Infectious Meningitis

OBJECTIVE: To compare the contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR), the CE T1-weighted (CE-T1W) sequence with fat suppression (FS) and magnetization transfer (MT) for early detection and characterization of infectious meningitis. MATERIALS AND METHODS: Fifty patients and 10 control subjects were evaluated with the CE-FLAIR and the CE-T1W sequences with FS and MT. Qualitative assessment was done by two observers for presence and grading of abnormal leptomeningeal enhancement. Quantitative assessment included computation of net meningeal enhancement, using single pixel signal intensity software. A newly devised FLAIR based scoring system, based on certain imaging features including ventricular dilatation, ependymal enhancement, infarcts and subdural effusions was used to indicate the etiology. Data were analysed using the Student's t test, Cohen's Kappa coefficient, Pearson's correlation coefficient, the intraclass correlation coefficient, one way analysis of variance, and Fisher's exact test with Bonferroni correction as the post hoc test. RESULTS: The CE-FLAIR sequence demonstrated a better sensitivity (100%), diagnostic accuracy (95%), and a stronger correlation with the cerebrospinal fluid, total leukocyte count (r = 0.75), protein (r = 0.77), adenosine deaminase (r = 0.81) and blood glucose (r = -0.6) values compared to the CE-T1W sequences. Qualitative grades and quantitative meningeal enhancement on the CE-FLAIR sequence were also significantly greater than those on the other sequences. The FLAIR based scoring system yielded a diagnostic accuracy of 91.6% and a sensitivity of 96%. A strong inverse Pearson's correlation (r = -0.95) was found between the assigned score and patient's Glasgow Coma Scale at the time of admission. CONCLUSION: The CE-FLAIR sequence is better suited for evaluating infectious meningitis and could be included as a part of the routine MR imaging protocol.

Hyperintensity of Subarachnoid Space on FLAIR Images Caused by Supplemental Oxygen

A hyperintensity in the subarachnoid space on fluid-attenuated inversion-recovery (FLAIR) images is often caused by diseases such as subarachnoid hemorrhage or meningitis. Oxygen has a known paramagnetic effect and also causes signal changes in the subarachnoid space on FLAIR images. These changes usually develop when the inspired air contains a high oxygen fraction. Here we present a patient with a hyperintensity in the subarachnoid space on FLAIR images whose inspired air contained only a low oxygen fraction.

Clinical Implications of Sulcal Enhancement on Postcontrast Fluid Attenuated Inversion Recovery Images in Patients with Acute Stroke Symptoms

OBJECTIVE: Hyperintense acute reperfusion marker (HARM) without diffusion abnormalities is occasionally found in patients with an acute stroke. This study was to determine the prevalence and clinical implications of HARM without diffusion abnormalities. MATERIALS AND METHODS: There was a retrospective review of magnetic resonance images 578 patients with acute strokes and identified those who did not have acute infarction lesions, as mapped by diffusion-weighted imaging (DWI). These patients were classified into an imaging-negative stroke and HARM without diffusion abnormalities groups, based on the DWI findings and postcontrast fluid attenuated inversion recovery images. The National Institutes of Health Stroke Scale (NIHSS) scores at admission, 1 day, and 7 days after the event, as well as clinical data and risk factors, were compared between the imaging-negative stroke and HARM without diffusion abnormalities groups. RESULTS: Seventy-seven acute stroke patients without any DWI abnormalities were found. There were 63 patients with an imaging-negative stroke (accounting for 10.9% of 578) and 13 patients with HARM without diffusion abnormalities (accounting for 2.4% of 578). The NIHSS scores at admission were higher in HARM without diffusion abnormalities group than in the imaging-negative stroke group (median, 4.5 vs. 1.0; p < 0.001), but the scores at 7 days after the event were not significantly different between the two groups (median, 0 vs. 0; p = 1). The patients with HARM without diffusion abnormalities were significantly older, compared with patients with an imaging-negative stroke (mean, 73.1 years vs. 55.9 years; p < 0.001). CONCLUSION: Patients with HARM without diffusion abnormalities are older and have similarly favorable short-term neurological outcomes, compared with the patients with imaging-negative stroke.

Quantitative Analysis of the Facial Nerve Using Contrast-Enhanced Three Dimensional FLAIR-VISTA Imaging in Pediatric Bell's Palsy

PURPOSE: To evaluate the usefulness of quantitative analysis of the facial nerve using contrast-enhanced three-dimensional (CE 3D) fluid-attenuated inversion recovery-volume isotopic turbo spin echo acquisition (FLAIR-VISTA) for the diagnosis of Bell's palsy in pediatric patients. MATERIALS AND METHODS: Twelve patients (24 nerves) with unilateral acute facial nerve palsy underwent MRI from March 2014 through March 2015. The unaffected sides were included as a control group. First, for quantitative analysis, the signal intensity (SI) and relative SI (RSI) for canalicular, labyrinthine, geniculate ganglion, tympanic, and mastoid segments of the facial nerve on CE 3D FLAIR images were measured using regions of interest (ROI). Second, CE 3D FLAIR and CE T1-SE images were analyzed to compare their diagnostic performance by visual assessment (VA). The sensitivity, specificity, and accuracy of RSI measurement and VA were compared. RESULTS: The absolute SI of canalicular and mastoid segments and the sum of the five mean SI (total SI) were higher in the palsy group than in the control group, but with no significant differences. The RSI of the canalicular segment and the total SI were significantly correlated with the symptomatic side (P = 0.028 and 0.015). In 11/12 (91.6%) patients, the RSI of total SI resulted in accurate detection of the affected side. The sensitivity, specificity, and accuracy for detecting Bell's palsy were higher with RSI measurement than with VA of CE 3D FLAIR images, while those with VA of CE T1-SE images were higher than those with VA of CE 3D FLAIR images. CONCLUSION: Quantitative analysis of the facial nerve using CE 3D FLAIR imaging can be useful for increasing the diagnostic performance in children with Bell's palsy when difficult to diagnose using VA alone. With regard to VA, the diagnostic performance of CE T1-SE imaging is superior to that of CE 3D FLAIR imaging in children. Further studies including larger populations are necessary.

Ivy Sign on Fluid-Attenuated Inversion Recovery Images in Moyamoya Disease: Correlation with Clinical Severity and Old Brain Lesions

PURPOSE: Leptomeningeal collateral, in moyamoya disease (MMD), appears as an ivy sign on fluid-attenuated inversion-recovery (FLAIR) images. There has been little investigation into the relationship between presentation of ivy signs and old brain lesions. We aimed to evaluate clinical significance of ivy signs and whether they correlate with old brain lesions and the severity of clinical symptoms in patients with MMD. MATERIALS AND METHODS: FLAIR images of 83 patients were reviewed. Each cerebral hemisphere was divided into 4 regions and each region was scored based on the prominence of the ivy sign. Total ivy score (TIS) was defined as the sum of the scores from the eight regions and dominant hemispheric ivy sign (DHI) was determined by comparing the ivy scores from each hemisphere. According to the degree of ischemic symptoms, patients were classified into four subgroups: 1) nonspecific symptoms without motor weakness, 2) single transient ischemic attack (TIA), 3) recurrent TIA, or 4) complete stroke. RESULTS: TIS was significantly different as follows: 4.86+/-2.55 in patients with nonspecific symptoms, 5.89+/-3.10 in patients with single TIA, 9.60+/-3.98 in patients with recurrent TIA and 8.37+/-3.39 in patients with complete stroke (p=0.003). TIS associated with old lesions was significantly higher than those not associated with old lesions (9.35+/-4.22 vs. 7.49+/-3.37, p=0.032). We found a significant correlation between DHI and motor symptoms (p=0.001). CONCLUSION: Because TIS has a strong tendency with severity of ischemic motor symptom and the presence of old lesions, the ivy sign may be useful in predicting severity of disease progression.

The study on estimation of the onset time by fluid-attenuated inversion recovery in acute ischemic stroke / 中国神经精神疾病杂志

Objective To explore whether fluid-attenuated inversion recovery can be used to estimate the onset time of acute ischemic stroke (ALS) based on the analysis of signal strength through the fluid-attenuated inversion-recov?ery (FLAIR)and volume of interest (ROI) in ALS patients with known time of onset. Method Forty-seven AIS patients who met the inclusion criteria were recruited from Baotou Central Hospital, Department of Neurology from January 2011 to December 2012. The patients had stroke onset within 12 hours and completed MRI scan including diffusion-weighted imaging DWI, apparent diffusion and coefficient ADC FLAIR. Based on MRI findings, patients were divided into, three groups:0~180 min, 180~360 min and 360~720 min groups. Signal strength values of the DWI、FLAIR and ADC in ipsi?lateral and contralateral sides were measured. Result There was a significant difference in the FLAIR signal strength among these three groups.The FLAIR signal strength was significantly lower in 0~180 min and 180~360 min groups than in 360-720 min. FLAIR positive rate was 16.7%, 62.5%, and 70.6% in 0~180 min, 180~360 min and 360~729 min groups, respectively. Conclusion FLAIR positive rate gradually increases as the onset prolongs. Thus, lower FLAIR posi?tive rate indicates shorter onset time of AIS, which can be used to assist acute intravenous thrombolytic therapy.

The Correlation Analysis of Endolymphatic Hydrops Degree in Vestibule and the Symptoms and Audiovestibular Functions in Patients with Meniere’s Disease / 听力学及言语疾病杂志

Objective To evaluate the correlation between the endolymphatic hydrops in vestibule and symp‐toms ,audiovestibular functions in patients with Meniere's disease .Methods Twenty -four hours after bilateral intra-tympanic 8 times diluted gadolinium administration , three - dimensional fluid - attenuated inversion recovery MRI ,using a three-Tesla unit ,was performed in 34 patients .The extent of endolymphatic hydrops in the MRI images was assessed and compared the hydrops with age ,duration ,stage of the disease ,frequency of attacks ,pure tone audiometry ,caloric test ,electrocochleography and vestibular evoked myogenic potentials .Results Thirty -four patients showed different levels of enhancement of perilymth in the inner ears .In these patients ,obvious signs of endolymphatic hydrops were visualized ,including 8 slight hydrops ,11 mild hydrops and 15 significant hydrops . In all 34 patients ,the results of PTA were 9 dB HL to 90 dB HL ,with average of 43 .56 dB HL and there were 21 abnormal and 13 normal patients in caloric test with a diagnostic rate 61 .76% ;17 normal ,7 abnormal and 10 not elicited patients in VEMP with a diagnostic rate 50% ;22 abnormal and 12 normal patients in electrocochleography with a diagnostic rate 64 .71% .There were almost no complications in all 34 patients after bilateral intra-tympanic injec‐tion except short vertigo among 5 of them .A statistically significant correlation was found between degrees of en‐dolymphatic hydrops in vestibule and age ,stage of the disease and VEMP (P 0 .05) and the correlation coefficient were 0 .494 ,0 .568 ,0 .590 , 0 .495 ,respectively .Conclusion The degree of endolymphatic hydrops in Ménière's disease has significant correlation with age ,VEMP ,stage of the disease and pure tone audiometry .No significant correlation was found between hy‐drops and duration ,frequency of attacks ,functional level scale ,caloric test and electrocochleography .

Accuracy of hyperintense cerebrospinal fluid signals (CSF) on inversion recovery (IR) images of brain in the diagnosis of meningitisa cost effective experience from third world country.

Objective: To detect the diagnostic accuracy of inversion recovery sequence in detection of meningitis taking cerebrospinal fluid as the gold standard. Material and Methods: This study was conducted in Aga Khan University Hospital (AKUH) Karachi. Retrospective data was reviewed from 1ST November 2010 to 31st November 2012. All consecutive patients who came with clinical diagnosis of meningitis were included. Fifty patients were included in study on the basis of inclusion and exclusion criteria. Two independent neuroradiologists retrospectively reviewed FLAIR sequences blinded to CSF findings. Their findings were compared with cerebrospinal fluid results. Sensitivity, specificity, PPV, NPV and diagnostic accuracy were calculated. Results: Hyperintense CSF signals on FLAIR sequence found to have 94.7% sensitivity, 83.3% specificity and accuracy of 92% in diagnosis of meningitis while PPV and NPV were 94.7% and 83.3% respectively. Conclusion: We found that hyper intense CSF signals on FLAIR sequence has high accuracy in diagnosis of meningitis.

Role of 3D FLAIR in demonstration of peripheral lesions of brainstem and cranial neuropathies.

Aim: We present a pictorial review of 3D FLAIR images depicting its importance in demonstrating the peripheral lesions of brainstem particularly in relation to attachment of cranial nerves and cranial neuropathies and particularly in context of patients with multiple sclerosis (MS). Discussion: T2 axials and routine 2D FLAIR have drawbacks in depicting the lesions on the peripheral aspects of brainstem. Such lesions are commonly found in MS. The revised McDonald’s criteria (2010) put equal emphasis on periventricular, juxtacortical, infratentorial and cord lesions. Detection of peripheral lesions thus play important role in fulfilling the criteria of dissemination in space and also provide anatomic correlate in several cranial nerve palsies. In clinically isolated syndromes, demonstration of lesions at the site of affected cranial nerves increase diagnostic confidence and exclude other potential disease processes. Ability to show signal changes at cranial nerve attachment can also potentially prevent a false attribution of symptoms to neurovascular compression. Conclusion: We propose that 3D FLAIR sequence is extremely useful in detecting abnormalities on the surface of brainstem and cranial nerve attachments and should be performed in all patients of MS and cranial nerve palsies.

A rare case of third ventricular epidermoid cyst as seen by newer MRI sequences.

Aim: We describe a 52 year old gentleman who had a third ventricular lesion, presumed to be epidermoid cyst, which is very rare. We also describe the appearances of this rare condition on newer MRI sequences. Presentation of Case: Third ventricle is a rare site of epidermoid cysts and difficult to visualise specially in routine MRI sequences. We used 3D FLAIR sequence as part of routine MRI protocol that was helpful in raising suspicion initially, aided by clinical presentation. Subsequent 3D T2 SPACE sequence confirmed the presence of abnormality. Discussion: The case highlights the importance of high resolution 3D FLAIR sequence as part of initial MRI protocol that is devoid of CSF flow artefacts and therefore helpful for small intraventricular lesions. Importance of 3D T2 SPACE is also highlighted which is another new MRI sequence. It has excellent spatial resolution without artefacts that is helpful in clearly delineating the presence of small lesions such as epidermoid cyst and its relationship with surrounding structures and increasing diagnostic certainty. Conclusion: We present a rare case of presumed third ventricular epidermoid cyst and potential role of newer MRI sequences in small intraventricular lesions.

Hyperintense Cerebrospinal Fluid on Fluid Attenuation Inverse Recover Image Caused by Left Internal Carotid Arterty Stenosis

No abstract available.

Study of optimization of FLAIR pulse sequence for image quality / 实用放射学杂志

Objective To explore the effect on image quality and scanning time by changing parameters and using different scan-ning technique for the clinical application of axial FLAIR pulse sequence.Methods Seven different sets of parameters of T2-FLAIR Pulse Sequences were performed on thirty patients at a 3.0 T MR scanner.Group A was scanned with a routine sequence for refer-ence.Group B,reducing the matrix to 128.Group C,increasing the turbo factor parameter to 24.Group D,setting the contatena-tion to 1.Group E setting the Accel.factor PE to 4.Group F,using a BLADE-FLAIR sequence.Group G,using a HASTE-FLAIR sequence.The SNRs of all images were statistically analyzed by ANOVA among 7 sequences.The image quality of all images was statistically analyzed by Kruskal-Wallis test among 7 sequences.Results The SNR of seven groups of images were 54.69 ±8.12, 1 57.57±25.61,44.56±7.37,38.48 ± 9.32,44.1 9 ±8.79,45.60 ± 6.92,105.20 ± 18.25,respectively(F = 266.368,P =0.000). The scores of image quality were 3.87±0.09,2.50±0.12,3.72±0.1 6,3.10±0.10,1.88±0.10,3.92±0.07,2.08±0.10,re-spectively and the differences among groups were statistically significant(χ2 =1 93.361,P =0.000).Conclusion Suitable turto factor and BLADE technique can be the best option for FLAIR sequence in the head.HASTE-FLAIR sequence can act as the secondary op-tion for the uncooperative patients.

Juxtacortical Spots on Fluid-Attenuated Inversion Recovery Images in Cryptogenic Transient Ischemic Attack

BACKGROUND AND PURPOSE: Juxtacortical spots are detected frequently on fluid-attenuated inversion recovery (FLAIR) images, but have not been extensively researched in patients with transient ischemic attack (TIA). We hypothesized that juxtacortical spots on FLAIR images are partly associated with right-to-left shunt (RLS) in TIA without clear etiology. The possibility of an association between the presence of RLS and juxtacortical spots on FLAIR images in patients with TIA without clear etiology was investigated, and the imaging findings of patients with and without RLS were compared. METHODS: This was a retrospective study of TIA patients who visited our tertiary stroke center consecutively within 72 hours of TIA onset. Cryptogenic TIA was defined as no clear etiology despite a routine diagnostic workup. The presence of RLS was examined by transcranial Doppler with an agitated saline test or transesophageal echocardiography. Juxtacortical spots were defined as small and round hyperintensities in the juxtacortex on FLAIR images, excluding white-matter hyperintensities. RESULTS: Of the 132 patients with cryptogenic TIA examined for this study, 70 (53.0%) had RLS. Juxtacortical spots on FLAIR images were detected more frequently in patients with RLS than in those without. The independent factors for the presence of juxtacortical spots were RLS [odds ratio (OR)=3.802, 95% confidence interval (95% CI)=1.74-8.2; p=0.001] and age (OR=1.058, 95% CI=1.01-1.10; p=0.004) by multivariate analysis. The number of juxtacortical spots was significantly higher among patients with a moderate-to-large RLS than in those with a small or no RLS. CONCLUSIONS: The findings of the present study demonstrate a significant association between the presence of RLS and the occurrence of juxtacortical spots on FLAIR images in patients with cryptogenic TIA.

The Usefulness of the Ivy Sign on Fluid-Attenuated Intensity Recovery Images in Improved Brain Hemodynamic Changes after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Adult Patients with Moyamoya Disease

OBJECTIVE: MR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images. METHODS: We enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery. RESULTS: Ivy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis. CONCLUSION: After STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

Applications of fluid-attenuated inversion recovery sequence in patients with acute ischemic stroke / 国际脑血管病杂志

The fluid-attenuated inversion recovery (FLAIR) sequence technique is widely used in each system organ examination in clinical practice.It has an important value for the diagnosis of various diseases,especially for central nervous system examination.This article reviews the applications and related research of FLAIR technique in patients with acute ischemic stroke.