小儿头部FLAIR图像上脑室内脑脊液搏动伪影(VCSFA)的探究

目的 探讨小儿头部液体衰减反转恢复(FLAIR)图像上脑室内脑脊液搏动伪影(VCSFA)的发生率及影像表现.方法 搜集做过头部FLAIR序列小儿100例,分成未见异常组、脑室形态异常组、脑室形态正常伴颅内病变组.统计VCSFA发生率及影像表现.结果 VCSFA在第三、四脑室内常见,导水管内少见.脑室形态异常组发生率最高,好发于盂氏孔、第三、四脑室顶部、导水管末端,呈高信号.结论 VCSFA在小儿FLAIR图像上常见,影像表现特异,脑室形态异常对VCSFA发生有一定影响.     

MR螺旋桨技术消除颅脑各种伪影的临床应用价值

目的:比较MR螺旋桨技术T2WI序列与常规FSE T2WI序列减少运动伪影效果,评价其临床应用价值。材料和方法:随机对82例行头部常规检查者,同时行螺旋桨技术T2WI序列扫描。由2名高职MR室医师分别评价其血管搏动、眼球运动、脑脊液波动、头部运动伪影。结果:82例中,常规T2WI扫描产生血管搏动伪影56例计106条、眼球运动伪影59例(1例因金属伪影无意义)、脑脊液波动伪影29例32条;头运动伪影35例(5例因金属伪影影响观察)。螺旋桨技术T2WI扫描未产生血管搏动和眼球运动伪影、脑脊液搏动伪影4例、头运动伪影2例。结论:螺旋桨技术在消除常规头颅扫描中产生伪影有显著效果,对疾病的确诊具有临床意义,有较好的应用前景。     

FLAIR序列新进展及其在脊髓成像中的应用

液体衰减反转回复(FLAIR)序列是一种IR SE序列,通过长TI时间选择性的抑制脑脊液信号,消除CSF波动伪影和部分容积效应,增加病灶与正常组织的对比度,提高MRI对病灶的检出率及定性和定量诊断能力.随着FLAIR新技术的不断发展,如快速FLAIR序列(fast FLAIR)、平面回波FLAIR序列(EP FLAIR)、部分饱和FLAIR序列(PS FLAIR)以及半傅里叶单次采集快速FLAIR序列(HASTE FLAIR),这些新技术的出现使其更广泛应用于中枢神经系统检查.现有的研究表明其在脊髓疾病诊断中也具有重要的应用价值.     

回顾性电影法心电门控多层螺旋CT与常规HRCT肺部扫描的对照研究

目的 评价回顾性电影法心电门控多层螺旋CT(ECG-MSCT)肺部扫描的作用。资料与方法 选取2000年7月～2001年6月间行肺部CT检查者50例,男36例,女14例。其中最高心率为88次/min,最低心率为58次/min,平均72.8±12次/min。采用GE Light Speed多层螺旋CT机和SUN图像工作站完成所有病例的检查。首先行常规HRCT扫描,随后只对需要作对比的层面进行同部位ECG-MSCT扫描,并以产生搏动性伪影最明显处的肺实质图像为主要观察对象。将心电门控扫描图像转至工作站进行图像后处理,由3位放射科医师分别进行盲法阅片作同层面图像质量比较。对所有图像质量采用评分方法进行评价。结果 通过同层ECG-MSCT图像和常规HRCT图像伪影评分的比较,发现两者有显著性差异(P<0.001)。心脏搏动双重伪影出现率有明显减少(P<0.05);双轨征出现率也显著减少(P<0.05);星状伪影消除率为60％,较常规HRCT有明显改善(P<0.01)。采用ECG-MSCT和常规HRCT扫描,对消除呼吸运动伪影方面,两者无显著性差异(P>0.05)。结论 ECG-MSCT扫描方法简便易行,可明显消除心脏搏动伪影、双轨征及常见的星状伪影,从而提高了图像的诊断质量,减少由于伪影而造成的误诊。     

颅内动脉瘤流动伪影在不同MRI序列上的表现差异

目的 探讨颅内动脉瘤流动伪影在不同MRI序列上的表现.方法 对经DSA或手术证实同时合并有流动伪影的19例颅内动脉瘤的MRI资料进行回顾分析.使用GE Signa 1.0T超导型MRI扫描仪.全部患者均行脑SE序列T1WI和T2WI、GRE序列、FLAIR序列、对比增强T1WI及3D TOF MRA扫描.结果 颅内动脉瘤流动伪影在所有MRI序列图像上均表现为动脉瘤残腔水平的不规则条带状影,且均位于相位编码方向.19例颅内动脉瘤在FLAIR序列上均可显示流动伪影,GRE序列上显示18例,T2WI上显示17例,T1WI上显示9例.行Gd-DTPA增强的7例病人T1WI图像均显示相位编码方向上的流动伪影.GRE序列及FLAIR序列图像上的流动伪影强度大于SE序列;T2WI上的流动伪影强度大于T1WI;对比剂注入后T1WI增强图像上的流动伪影强度明显大于增强前图像.结论 不同MRI序列上颅内动脉瘤流动伪影的强度不同.     

MRI之FLAIR技术在诊断脑室型囊虫病的应用价值

目的评价液体衰减反转恢复(FLAIR)序列对脑室型囊虫病的应用价值.方法对1997-06～2000-06期间经0.5T超导型MR设备检查诊断为脑室型囊虫病有手术和病理结果者18例(手术证实16例,2例误诊)进行分析,并比较应用FLAIR序列与常规自旋回波(SE)序列的成像效果.结果本组病例中,FLAIR序列检出脑室内囊虫23个,常规SE序列检出12个(为FLAIR序列的52.2%),前者敏感性高.室内囊虫之内部结构与边缘情况亦以FLAIR序列显示为好.结论FLAIR序列用来抑制脑脊液自由水的信号,可进一步发现和明确在常规SE序列成像上未能见到的或可疑的室内病灶,故为常规SE序列检查的重要补充.本文就误诊原因进行讨论.     

参数选择对磁共振T2-FLAIR像中脑脊液高信号伪影的影响

目的:探讨磁共振T2-FLAIR成像中的参数选择与脑脊液高信号伪影抑制效果的关系.方法:用1.5T磁共振对50例患者行T2-FLAIR成像,根据检查参数不同分为以下4组:①下空间饱和带/采集间隔2;②下空间饱和带/流动补偿/采集间隔2;③下空间饱和带/流动补偿/定制射频脉冲/采集间隔2;下空间饱和带/流动补偿/定制射频脉冲/采集间隔3.观察分析4组不同成像参数T2-FLAIR像上桥前池、小脑延髓池等处脑脊液伪影的差别.结果:B组和A组在脑脊液伪影的抑制效果方面无明显差别(U=0.98,P＞0.05);C组对脑脊液伪影的抑制效果优于A组和B组(U=3.66,P＜0.01);D组对脑脊液伪影的抑制优于C组,效果最好(U=7.36,P＜0.01).结论:定制射频脉冲对磁共振脑脊液伪影有较好的抑制作用,可在T2-FLAIR序列中常规应用;定制射频脉冲结合3倍采集间隔可使脑脊液伪影更进一步地抑制.     

低心率下第二代双源CT冠脉成像Flash扫描与序列扫描图像质量及伪影比较

目的:比较低心率下CT前瞻性心电触发Flash扫描与序列扫描的冠状动脉图像质量及伪影。方法:回顾性连续收集Flash扫描(A组)与序列扫描(B组)冠状动脉CT成像各80例患者,心率均≤70次/min。4级法评价2组图像质量,初步分析伪影特点及成因。结果:A、B 2组可评价冠状动脉节段为98.37%和99.29%,差异无统计学意义(χ2=3.56,P=0.094);可评价患者为85.00%和96.25%,差异有统计学意义(χ2=4.708,P=0.035);平均节段质量评分为(1.295±0.60)分和(1.21±0.59)分,差异有统计学意义(Z=-2.591,P=0.010)。A组的4级图像大部分分布于右冠中远段,多数出现在心率大于65次/min的患者中,均为心脏搏动伪影。B组4级图像散在分布于冠脉各段中,为呼吸及心脏搏动伪影。A组辐射剂量明显低于B组,差异有统计学意义。结论:低心率下Flash与序列扫描均可获得高质量冠状动脉图像,序列扫描略优于Flash扫描;Flash扫描右冠状动脉中远段出现心脏搏动伪影概率大,序列扫描易产生呼吸及心律不齐所致伪影。     

超急性期流域性脑梗死在结合刀锋伪影纠正的液体衰减反转恢复(FLAIR)序列下动脉高信号:与常规液体衰减反转恢复的对比研究

正摘要目的比较结合了刀锋伪影纠正技术(BLADE)的液体衰减反转恢复(FLAIR)序列与常规FLAIR序列两种技术,评估两者对超急性期流域性脑梗死中动脉高信号(AH)     

正常胸部磁共振平扫和增强屏气扫描研究

目的总结胸部磁共振屏气扫描的方法,评价正常胸部磁共振屏气平扫和增强的图像特征和质量。方法经CT证实的正常胸部30例,行屏气T1WI、脂肪抑制T2WI、质子密度加权成像和增强后T1WI脂肪抑制成像扫描,分析图像特点,测量和统计肺实质、胸壁肌肉的信噪比;肺实质与胸壁肌肉的对比度和对比噪声比。结果 T1WI肺实质信号弱,心脏水平搏动伪影明显;脂肪抑制T2WI肺纹理较丰富,本底噪声较大,心脏大血管流动相关增强效应明显;质子密度加权成像肺实质信号均匀、且信号较强,无心脏和大血管搏动伪影。增强后T1WI脂肪抑制成像,肺实质和肺血管强化明显,心脏和主动脉搏动伪影明显。按上述顺序,肺实质的信噪比为1.70±0.17;2.77±0.54;4.10±0.72;2.79±0.57(P<0.001)。胸壁肌肉的信噪比为21.18±5.57;8.91±2.50;17.56±3.37;37.49±12.16(P<0.001)。肺实质与胸壁肌肉的对比度为0.91±0.02;0.47±0.08;0.78±0.05;0.88±0.03(P<0.001);肺实质与胸壁肌肉的对比噪声比为17.05±3.69;3.60±0.79;13.29±1.94;24.92±6.85(P<0.001)。结论磁共振四种屏气序列联合应用,有效地反映肺实质和胸壁肌肉组织的磁共振特性,避免伪影干扰。     

Intraventricular CSF pulsation artifact on fast fluid-attenuated inversion-recovery MR images: analysis of 100 consecutive normal studies

BACKGROUND AND PURPOSE: CSF pulsation artifact is a pitfall of fast fluid-attenuated inversion-recovery (FLAIR) brain MR imaging. We studied ventricular CSF pulsation artifact (VCSFA) on axial FLAIR images and its relationship to age and ventricular size. METHODS: Fast FLAIR axial images were obtained on a 1.5-T unit (8000/150/2 [TR/TE/ excitations], inversion time = 2200, field of view = 24 cm, matrix = 189x256, and 5-mm interleaved sections). Two observers rated VCSFA (hyperintensity on FLAIR images) in the lateral, third, and fourth ventricles by using a three-point ordinal scale in 100 consecutive subjects (ages 20-86 years) with normal brain MR studies. Left-to-right third ventricular width was also measured. RESULTS: Seventy-two subjects had VCSFA in at least one ventricular cavity. The fourth ventricle was the most common site of VCSFA (n = 58), followed by the third ventricle (n = 47) and the lateral ventricles (n = 13). VCSFA was usually severe in the third and fourth ventricles and less severe in the lateral ventricles. Fourth ventricular VCSFA was significantly associated with third ventricular VCSFA. Increasing third ventricular size and, to a lesser extent, increasing age was significantly associated with VCSFA. Ghost pulsation of VCSFA occurred across the brain parenchyma in the phase-encoding direction. VCSFA seen in the fourth ventricle on axial FLAIR images disappeared on sagittal FLAIR images in one subject. CONCLUSION: VCSFA on axial FLAIR images represents inflow artifact caused by inversion delay and ghosting effects. VCSFA might obscure or mimic intraventricular lesions, especially in the third and fourth ventricles. Although common in adults of all ages, VCSFA is associated with advancing age and increasing ventricular size. Thus, altered CSF flow dynamics that occur with ventriculomegaly and aging contribute to VCSFA on axial FLAIR MR images.     

Fluid-attenuated inversion-recovery MR imaging in acute and subacute cerebral intraventricular hemorrhage.

BACKGROUND AND PURPOSE: Fluid-attenuated inversion-recovery (FLAIR) MR imaging may show subarachnoid hemorrhage (SAH) with high sensitivity. We hypothesized that the FLAIR technique is effective and reliable in the diagnosis of cerebral intraventricular hemorrhage (IVH). METHODS: Two observers evaluated the 1.5-T MR fast spin-echo FLAIR images, T1- and T2-weighted MR images, and CT scans of 13 patients with IVH and the FLAIR images of 40 control subjects. RESULTS: IVH appeared bright on the FLAIR images obtained during the first 48 hours and was of variable appearance at later stages. FLAIR MR imaging detected 12 of 13 cases of IVH; no control subjects were falsely thought to have IVH (92% sensitivity, 100% specificity). However, IVH could not be fully excluded in the third ventricle (20%, n = 8) or in the fourth ventricle (28%, n = 11) on some control images because of CSF pulsation artifacts. Two cases had CT-negative IVH seen on FLAIR images. One case had FLAIR-negative IVH seen by CT. Although the sensitivities of conventional MR imaging (92%) and CT (85%) were also high, FLAIR imaging showed IVH more conspicuously than did standard MR imaging and CT in 62% of the cases (n = 8). FLAIR was as good as or better than CT in showing IVH in 10 cases (77%). FLAIR images showed all coexisting SAH. CONCLUSION: FLAIR MR imaging identifies acute and subacute IVH in the lateral ventricles with high sensitivity and specificity. In cases of subacute IVH, conventional MR imaging complements FLAIR in detecting IVH. The usefulness of the FLAIR technique for detecting third and fourth ventricular IVH may be compromised by artifacts. Blood hemoglobin degradation most likely causes the variable FLAIR appearance of IVH after the first 48 hours.     

Degenerative disc disease of the lumbar spine: a prospective comparison of fast T1-weighted fluid-attenuated inversion recovery and T1-weighted turbo spin echo MR imaging

OBJECTIVE: To compare fast T1-weighted fluid-attenuated inversion recovery (FLAIR) and T1-weighted turbo spin-echo (TSE) imaging of the degenerative disc disease of the lumbar spine. MATERIALS AND METHODS: Thirty-five consecutive patients (19 females, 16 males; mean age 41 years, range 31-67 years) with suspected degenerative disc disease of the lumbar spine were prospectively evaluated. Sagittal images of the lumbar spine were obtained using T1-weighted TSE and fast T1-weighted FLAIR sequences. Two radiologists compared these sequences both qualitatively and quantitatively. RESULTS: On qualitative evaluation, CSF nulling, contrast at the disc-CSF interface, the disc-spinal cord (cauda equina) interface, and the spinal cord (cauda equina)-CSF interface of fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P<0.001). On quantitative evaluation of the first 15 patients, signal-to-noise ratios of cerebrospinal fluid of fast T1-weighted FLAIR imaging were significantly lower than those for T1-weighted TSE images (P<0.05). Contrast-to-noise ratios of spinal cord/CSF and normal bone marrow/disc for fast T1-weighted FLAIR images were significantly higher than those for T1-weighted TSE images (P<0.05). CONCLUSION: Results in our study have shown that fast T1-weighted FLAIR imaging may be a valuable imaging modality in the armamentarium of lumbar spinal T1-weighted MR imaging, because the former technique has definite superior advantages such as CSF nulling, conspicuousness of the normal anatomic structures and changes in the lumbar spinal discogenic disease and image contrast and also almost equally acquisition times.     

The role of conventional MR imaging sequences in the evaluation of neurocysticercosis: impact on characterization of the scolex and lesion burden

BACKGROUND AND PURPOSE: There are few studies comparing the capacity of lesion detection of conventional MR imaging in neurocysticercosis (NCC). This study was designed to clarify its role in the evaluation of this disease, focusing on the total number of lesions identified and the characterization of the scolex. MATERIALS AND METHODS: MR images from 115 patients were prospectively collected during a 3-year interval, including axial spin-echo (SE) T1-weighted; axial fast SE T2-weighted; axial fluid-attenuated inversion recovery (FLAIR); and gadolinium-enhanced axial, coronal, and sagittal SE T1-weighted sequences. They were compared regarding the potential for detection of NCC lesions and specifically of the scolex. RESULTS: Comparing all sequences, we found that FLAIR images were more sensitive to the detection of the scolex (P < .003), whereas the last gadolinium-enhanced T1-weighted series (coronal or sagittal) identified the highest number of lesions (P < .001). CONCLUSION: When dealing with NCC, optimal MR imaging protocols should include FLAIR images to obtain maximal rates of scolex detection. Special attention should be paid to the last gadolinium-enhanced sequence, which maximizes the quantification of lesion load.     

Diffusion-weighted images in children with meningoencephalitis

PURPOSE: The objective of the study was to evaluate the maps of apparent diffusion coefficients (ADCs) and diffusion-weighted (DW) images in demonstrating meningoencephalitic lesions in children. MATERIALS AND METHODS: Between May 1998 and May 2000, 18 infants and children (4.5-190 months old) suffering from meningoencephalitis were included in the study. The diagnoses were bacterial meningoencephalitis in 8 and aseptic or viral in 10 patients. All 18 patients had brain MRI examinations. In the axial plane, three pulse sequences were performed on all patients: (1) FSE T2W images; (2) fast FLAIR images; (3) single-shot echoplanar DW images were acquired. Another 18 patients from the control group also received DW image examination. ADCs were computed for all regions on each DW image. RESULTS: The absolute values of CNRs of lesions on T2W (7.27+/-5.51), FLAIR (5.56+/-5.03) and DW (13.36+/-16.64) images were significantly greater than those on ADC maps (0.42+/-0.30) in the study group of patients (P<.01). In addition, absolute CNRs on DW images were significantly greater than on T2W and FLAIR images (P<.01). However, lesions on ADC maps in the study group have significantly greater CNRs than in the control group (0.13+/-0.12) (P<.01). CNRs on initial DW images from patients with atrophy or swelling of meningoencephalitic lesions were significantly different from the CNRs of those patients without significant changes in meningoencephalitic lesions (P=.02<.05). CONCLUSION: The DW image is a sensitive tool for detecting meningoencephalitic lesions and is better than FSE T2W and fast FLAIR images in CNRs. Diffusion MR techniques provides new ways to possibly predict the outcome of intracranial infectious diseases in children.     

Fast fluid-attenuated inversion-recovery (FLAIR) MRI in the assessment of intraaxial brain tumors

This study demonstrates the value of a fast fluid-attenuated inversion-recovery (FLAIR) technique in the assessment of primary intraaxial brain tumors. Twenty-one patients with primary intraaxial brain tumors were examined by T2-weighted, proton-density-weighted fast spin echo, fast FLAIR, and contrast-enhanced T1-weighted spin echo using identical slice parameters. The images were evaluated using quantitative and qualitative criteria. Quantitative criteria were tumor-to-background and tumor-to-cerebrospinal fluid (CSF) contrast and contrast-to-noise ratio (CNR). The qualitative evaluation was performed as a multi-reader analysis concerning lesion detection, lesion delineation, and image artifacts. In the qualitative evaluation, all readers found the fast FLAIR to be superior to fast spin echo in the exact delineation of intraaxial brain tumors (P < .001) and the delineation of enhancing and nonenhancing tumor parts. Fast FLAIR was superior in the delineation of cortically located and small lesions but was limited in lesions adjacent to the ventricles. Fast FLAIR provided a significantly better tumor-to-CSF contrast and tumor-to-CSF CNR (P < .001). The tumor-to-background contrast and tumor-to-background CNR of the fast FLAIR images were lower than those of T2-weighted spin-echo images but higher than those of proton-density-weighted spin-echo images. FLAIR images had more image artifacts influencing the image interpretation in only two patients. Signal hyperintensities at the ventricular border were present in 92% of the patients. They are common findings in fast FLAIR and should be included into the image interpretation.     

Hyperintensity of the precentral gyral subcortical white matter and hypointensity of the precentral gyrus on fluid-attenuated inversion recovery: variation with age and implications for the diagnosis of amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE: Hyperintensity of the subcortical white matter (SWM) of the precentral gyrus and hypointensity of the precentral gyrus gray matter (PGGM) on fluid-attenuated inversion recovery (FLAIR) are described as potentially useful diagnostic findings in amyotrophic lateral sclerosis (ALS). A detailed study of the prevalence of these findings in various age groups has not been described. METHODS: One hundred twenty-two patients underwent axial FLAIR brain examinations as part of either hearing loss or tinnitus evaluation. Examinations were randomly selected to reflect an even spread through the decades from ages 15 to 78 years and were reviewed by 2 readers, blinded to patient's age and sex, for the presence/absence of the above 2 signs. If SWM hyperintensity was present, it was graded as intense as caudate nucleus (grade 1) or insula (grade 2). RESULTS: We identified 32 cases of grade 1 and 5 cases of grade 2 SWM hyperintensity, and 28 cases of PGGM hypointensity. Both signs showed significant Spearman correlation with increasing age (r = 0.55, P < .001 for grade 1, r = 0.45, P < .001 for grade 2 SWM hyperintensity, r = 0.45, P < .001 for PGGM hypointensity). Analysis of variance showed there was a significant difference between the different age groups (P < .001) for both signs. Grading of the SWM and PGGM signals were highly reproducible with very good interobserver agreement (r = 0.88, P < .001, and r = 0.97, P < .001, respectively). CONCLUSION: This study suggests a statistically significant relationship between increasing age and the frequency of precentral gyrus SWM hyperintensity and PGGM hypointensity on FLAIR, and reinforces previous reports that these signs can be seen in patients who do not have ALS.     

Comparative evaluation of magnetization transfer contrast and fluid attenuated inversion recovery sequences in brain tuberculoma

AIM: To compare T1-weighted magnetization transfer (MT) with fluid attenuated inversion recovery (FLAIR) imaging for evaluating conspicuity and number of lesions in individuals with brain tuberculoma. MATERIALS AND METHODS: In all 28 patients with brain tuberculoma underwent MR examination using fast spin-echo (FSE) T2, spin-echo (SE) T1, T1-weighted MT and FLAIR imaging. Post-contrast T1-weighted MT imaging was taken as the gold standard for assessing the number of lesions. Tuberculomas detected both on T1-weighted MT and FLAIR imaging were examined for the wall to be defined, and were divided into two groups on the basis of presence (group 1) or absence (group 2) of perilesional oedema visible on FLAIR imaging. The mean signal intensity of the wall of the lesions and adjacent oedema or brain parenchyma was analyzed qualitatively and quantitatively. RESULTS: The number of lesions detected on T1-weighted MT was higher than on FLAIR imaging (209 versus 163). Conspicuity in both groups was better on T1-weighted MT images qualitatively as well as quantitatively. The difference in the signal intensity of the wall of the lesion and perilesional oedema was statistically significant only on T1-weighted MT images in group 1 (p=0.0003 versus 0.3), whereas in group 2 it was statistically significant both on T1-weighted MT and FLAIR imaging (p=0.009 versus 0.05). CONCLUSION: FLAIR imaging is not helpful in the examination of brain tuberculomas compared with T1-weighted MT imaging, as it neither contributes to the characterization of lesion nor assesses the true disease load.     

Hyperintensity of the middle cerebellar peduncles on fluid-attenuated inversion recovery imaging: variation with age and implications for the diagnosis of multiple system atrophy

BACKGROUND AND PURPOSE: T2 hyperintensity of the middle cerebellar peduncle (MCP) is described in a number of diseases, including multiple system atrophy (MSA). We hypothesize that mild MCP hyperintensity on fluid-attenuated inversion recovery (FLAIR) imaging can be a normal finding. To our knowledge, a detailed study of the prevalence of this finding in various age groups with the FLAIR sequence has not been described. METHODS: One hundred twenty-two patients underwent an axial FLAIR examination of the brain as part of either a hearing loss or tinnitus work-up (ie, to exclude an acoustic neuroma or a retrocochlear cause). Subjects aged 15-78 years were included to reflect an even spread through the decades and were divided into 6 age groups. A radiologist and an MR imaging fellow graded the examinations subjectively, blinded to age: 0 for normal or 1 for the presence of MCP hyperintensity if the increased signal intensity was greater than that of adjacent pons and cerebellar white matter. Spearman rank correlation test of MCP hyperintensity with age and analysis of variance (ANOVA) were performed. RESULTS: Of 122 patients, we identified 17 with MCP FLAIR hyperintensity. None of these patients had a clinical condition that could cause MCP hyperintensity. MCP hyperintensity did not show a statistically significant correlation with age (r = 0.05, P = .62). Patients were divided into 6 age groups, and ANOVA showed no statistically significant difference in the incidence of MCP hyperintensity between different age groups (P = .95). However, results were highly reproducible with excellent interobserver correlation (r = 0.97, P < .001). CONCLUSIONS: Mild MCP FLAIR hyperintensity can occur normally, and this finding shows no relationship with age.     

Serial isotropic three-dimensional fast FLAIR imaging: using image registration and subtraction to reveal active multiple sclerosis lesions

OBJECTIVE: Image registration and subtraction to detect the change of disease burden in multiple sclerosis on serial MR images should benefit from the use of high-resolution isotropic voxels. We compared 1.2-mm isotropic three-dimensional (3D) fast fluid-attenuated inversion recovery (FLAIR) images with standard 3-mm two-dimensional spin-echo images for the detection of new or enlarging lesions in longitudinal studies. SUBJECTS AND METHODS: Serial MR images were obtained at baseline, month 6 (n = 20), and month 7 (n = 16). For the half-yearly intervals, subtracted 3D FLAIR images and T2-weighted spin-echo images were compared. For the monthly intervals, subtracted 3D FLAIR images were compared with triple-dose contrast-enhanced T1-weighted spin-echo images. New, enlarging, and enhancing lesions were marked in consensus by two radiologists. RESULTS: At the half-yearly intervals, 3D FLAIR imaging detected more new or enlarging lesions than T2-weighted spin-echo imaging, both at the initial interpretation (80 vs 52; p < 0.001) and after a side-by-side comparison of the lesions (88 vs 65; p < 0.001). Post hoc analyses showed the largest benefit for new (rather than enlarging), for small, and for temporal lesions. At the monthly intervals, 32 enhancing lesions were detected on contrast-enhanced T1-weighted spin-echo images versus 20 new or enlarging lesions detected on 3D FLAIR images (p < 0.05). After a side-by-side comparison of the lesions, seven additional lesions were identified on 3D FLAIR images, making the difference with contrast-enhanced T1-weighted spin-echo images insignificant (27 vs 32; p > 0.05). CONCLUSION: Isotropic 3D FLAIR imaging holds great promise for the detection of new or enlarging lesions in multiple sclerosis using registration and subtraction techniques certainly at longer intervals.