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Lani · 07-28-2018, 02:13 AM

FLAIR abnormalities are found on brain mris on on many "normal" people --especially if mri done at 3t rather than 1.5 T(you did not specify which you had)

http://www.ajnr.org/content/30/5/911

Normal Findings on Brain Fluid-Attenuated Inversion Recovery MR Images at 3T

Abstract

BACKGROUND AND PURPOSE: Fluid attenuated inversion recovery (FLAIR) MR imaging of the brain has become a routine tool for assessing lesions in patients with suspected neurologic disorders. There is growing interest in 3T brain FLAIR MR imaging but little normative data are available. The purpose of this study was to evaluate the frequency and topography of cerebral hyperintensities seen with FLAIR MR imaging of the brain at 3T in a normal population and compare those findings to 1.5T.

MATERIALS AND METHODS: Whole-brain 2D FLAIR MR imaging was performed in 22 healthy controls (mean age, 44 ± 8 years; range, 30–53 years) at 3T. Fifteen of these subjects also underwent 2D FLAIR at 1.5T, with similar optimized parameters and voxel size. Cerebral hyperintense areas, including discrete foci, anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts were assessed. The Spearman rank test assessed the correlation between discrete hyperintense foci and age. The Wilcoxon signed rank test compared foci detectability at 3T versus 1.5T.

RESULTS: FLAIR at 3T commonly showed hyperintensities such as discrete foci (mean, 10.68 per subject; at least 1 present in 68% of subjects), anterior and posterior periventricular capping, diffuse posterior white matter hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and ventricular CSF flow artifacts. FLAIR at 3T showed a higher hyperintense foci volume (170 ± 243 versus 93 ± 152 mm3, P < .01) and number (9.4 ± 13 versus 5.5 ± 9.2, P < .01) than at 1.5T. No significant differences (P = .68) in the length/diameter of individual discrete hyperintense foci were seen between 3T and 1.5T. Discrete foci volume (r = 0.72 at 3T, r = 0.70 at 1.5T) and number (r = 0.74 at 3T; r = 0.69 at 1.5T) correlated with age to a similar degree on both platforms. All discrete foci were confined to the noncallosal supratentorial white matter. The other nonfocal hyperintensities (anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts) were generally more common and prominent at 3T than at 1.5T.

CONCLUSIONS: Discrete and diffuse parenchymal brain white matter FLAIR hyperintensities are more common and prominent at 3T than at 1.5T in healthy volunteers.

Materials and Methods

Subject Characteristics and Image Acquisition

We examined 22 adult healthy volunteers (mean age, 44 ± 8 years; range, 30–53 years). This Health Insurance Portability and Accountability Act−compliant study included institutional review board (IRB) approval and informed consent. Participants for this study were recruited by using an IRB-approved advertisement that was posted in a local newspaper and our hospital Website. A telephone interview was conducted by using a questionnaire, and any potential participants with a history of major medical, neurologic, or neuropsychiatric disorders and current or previous history of substance abuse were excluded. For example, questions were asked to exclude subjects who had a history of hypertension, diabetes, head trauma, migraine, learning disabilities, depression, bipolar disorder, alcohol/tobacco/recreational drug abuse, or any conditions that would preclude MR imaging. Regarding tobacco, we excluded any individuals with current or recent (within 5 years) use. Entry into the study was on the basis of patient-reported history: no formal bedside physical or neurologic examination or neuropsychiatric testing was performed. Imaging of the brain was performed in 15 of these subjects (mean age, 43 ± 8 years; range, 30–53 years) at both 1.5T and 3T; an additional 7 subjects were interested in having only 1 scan due to the time commitment and thus were scanned at 3T only. There was no significant (P = .75) age difference between the subject groups studied at 1.5T and 3T. Subjects underwent 2D fast FLAIR MR imaging of the brain; technical details on the scan protocol are provided in Table 1. Due to the potential at 3T to exceed specific absorption rate, patient safety limitations, and scanning time considerations, TR, TE, and echo-train length varied between the 2 platforms, though voxel size was nearly equivalent.11

Table 1:
MR imaging protocol and technique

Due to a change in scanning protocol early in the project, the section thickness for the scans was slightly variable between but generally not within subjects. Of the total 22 subjects scanned at 3T, 18 were scanned with the main protocol shown in Table 1 by using 2-mm-thick axial sections and 4 were scanned with a similar protocol by using a 3-mm section thickness. Of the 15 subjects scanned at 1.5T, 14 were scanned with the 2-mm protocol and 1 subject was scanned with the 3-mm protocol. Only 1 subject scanned at both 1.5T and 3T had variable section thicknesses between platforms; but because this subject did not show any discrete hyperintense foci, we did not exclude this subject from the analysis. Otherwise, the scanning protocol for the 22 subjects was similar within and across subjects.

Image Analysis

Image analysis was performed by using the software package Jim, Version 3.0 (Xinapse Systems, Northants, UK; http://www.xinapse.com). Scans were anonymized and randomized for analysis. Discrete areas of increased signal-intensity abnormality on FLAIR images, referred to as “hyperintense foci,” were identified by the consensus of 3 trained observers and confirmed by an experienced observer to resolve any discrepancies. We avoided using the term “lesions” to describe the foci because of the normative population being studied. The number and volume of FLAIR hyperintense discrete foci were assessed through an edge-finding tool based on local thresholding that was applied to each axial section to identify discrete foci contours. Manual adjustments were applied where necessary. The maximum width or length of each hyperintense focus and the anterior hyperintense capping of the ventricles were assessed with a measurement tool. Hyperintense areas not well suited to quantitative analysis, such as diffuse white matter hyperintensity, septal hyperintensity,4 corticospinal tract hyperintensity,4 and ventricular CSF flow artifacts,12 were qualitatively described.

Statistical Analysis

The Spearman rank correlation analysis was used to assess the relationship between FLAIR discrete hyperintense foci number or volume and age. Wilcoxon signed rank test was used to assess the difference between age and discrete hyperintense foci detectability on the 1.5 and 3T platforms. A modified Wilcoxon test13 for clustered data was used to assess the difference between discrete hyperintense foci length on the 1.5 and 3T platforms. The Choi test14 assessed the differences between correlations on the 1.5T versus 3T platform. For all analysis, a P value < .05 was considered statistically significant in this exploratory study.

[I]If becomes difficult to resolve what your mri findings mean, suggest you consult Penny Sneed MD @ UCSF whose specialty of 35 yrs is the diagnosing and treatment of brain mets from breast cancer. Thoughtful, forthright, no-nonsense and reassuring to those "thinking" the worst. I learned from her that sometimes it is better to go with the older technology 1.5 vs 3T brain MRI and FLAIR is often
"normal".

07-28-2018, 02:13 AM	#48
Lani Senior Member Join Date: Mar 2006 Posts: 4,778	Re: Cancer 'n Me FLAIR abnormalities are found on brain mris on on many "normal" people --especially if mri done at 3t rather than 1.5 T(you did not specify which you had) http://www.ajnr.org/content/30/5/911 Normal Findings on Brain Fluid-Attenuated Inversion Recovery MR Images at 3T Abstract BACKGROUND AND PURPOSE: Fluid attenuated inversion recovery (FLAIR) MR imaging of the brain has become a routine tool for assessing lesions in patients with suspected neurologic disorders. There is growing interest in 3T brain FLAIR MR imaging but little normative data are available. The purpose of this study was to evaluate the frequency and topography of cerebral hyperintensities seen with FLAIR MR imaging of the brain at 3T *in a normal population* and compare those findings to 1.5T. MATERIALS AND METHODS: Whole-brain 2D FLAIR MR imaging was performed in 22 healthy controls (mean age, 44 ± 8 years; range, 30–53 years) at 3T. Fifteen of these subjects also underwent 2D FLAIR at 1.5T, with similar optimized parameters and voxel size. Cerebral hyperintense areas, including discrete foci, anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts were assessed. The Spearman rank test assessed the correlation between discrete hyperintense foci and age. The Wilcoxon signed rank test compared foci detectability at 3T versus 1.5T. RESULTS: FLAIR at 3T commonly showed hyperintensities such as discrete foci (mean, 10.68 per subject; *at least 1 present in 68% of subjects), anterior and posterior periventricular capping, diffuse posterior white matter hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and ventricular CSF flow artifacts. FLAIR at 3T showed a higher hyperintense foci volume (170 ± 243 versus 93 ± 152 mm3, P < .01) and number (9.4 ± 13 versus 5.5 ± 9.2, P < .01) than at 1.5T. No significant differences (P = .68) in the length/diameter of individual discrete hyperintense foci were seen between 3T and 1.5T. Discrete foci volume (r = 0.72 at 3T, r = 0.70 at 1.5T) and number (r = 0.74 at 3T; r = 0.69 at 1.5T) correlated with age to a similar degree on both platforms. All discrete foci were confined to the noncallosal supratentorial white matter. The other nonfocal hyperintensities (anterior and posterior periventricular capping, diffuse parenchymal hyperintensity, septal hyperintensity, corticospinal tract hyperintensity, and CSF flow artifacts) were generally more common and prominent at 3T than at 1.5T. CONCLUSIONS: Discrete and diffuse parenchymal brain white matter FLAIR hyperintensities are more common and prominent at 3T than at 1.5T in healthy volunteers. Materials and Methods Subject Characteristics and Image Acquisition We examined 22 adult healthy volunteers* (mean age, 44 ± 8 years; range, 30–53 years). This Health Insurance Portability and Accountability Act−compliant study included institutional review board (IRB) approval and informed consent. Participants for this study were recruited by using an IRB-approved advertisement that was posted in a local newspaper and our hospital Website. A telephone interview was conducted by using a questionnaire, and any potential participants with a history of major medical, neurologic, or neuropsychiatric disorders and current or previous history of substance abuse were excluded. For example, questions were asked to exclude subjects who had a history of hypertension, diabetes, head trauma, migraine, learning disabilities, depression, bipolar disorder, alcohol/tobacco/recreational drug abuse, or any conditions that would preclude MR imaging. Regarding tobacco, we excluded any individuals with current or recent (within 5 years) use. Entry into the study was on the basis of patient-reported history: no formal bedside physical or neurologic examination or neuropsychiatric testing was performed. Imaging of the brain was performed in 15 of these subjects (mean age, 43 ± 8 years; range, 30–53 years) at both 1.5T and 3T; an additional 7 subjects were interested in having only 1 scan due to the time commitment and thus were scanned at 3T only. There was no significant (P = .75) age difference between the subject groups studied at 1.5T and 3T. Subjects underwent 2D fast FLAIR MR imaging of the brain; technical details on the scan protocol are provided in Table 1. Due to the potential at 3T to exceed specific absorption rate, patient safety limitations, and scanning time considerations, TR, TE, and echo-train length varied between the 2 platforms, though voxel size was nearly equivalent.11 Table 1: MR imaging protocol and technique Due to a change in scanning protocol early in the project, the section thickness for the scans was slightly variable between but generally not within subjects. Of the total 22 subjects scanned at 3T, 18 were scanned with the main protocol shown in Table 1 by using 2-mm-thick axial sections and 4 were scanned with a similar protocol by using a 3-mm section thickness. Of the 15 subjects scanned at 1.5T, 14 were scanned with the 2-mm protocol and 1 subject was scanned with the 3-mm protocol. Only 1 subject scanned at both 1.5T and 3T had variable section thicknesses between platforms; but because this subject did not show any discrete hyperintense foci, we did not exclude this subject from the analysis. Otherwise, the scanning protocol for the 22 subjects was similar within and across subjects. Image Analysis Image analysis was performed by using the software package Jim, Version 3.0 (Xinapse Systems, Northants, UK; http://www.xinapse.com). Scans were anonymized and randomized for analysis. Discrete areas of increased signal-intensity abnormality on FLAIR images, referred to as “hyperintense foci,” were identified by the consensus of 3 trained observers and confirmed by an experienced observer to resolve any discrepancies. We avoided using the term “lesions” to describe the foci because of the normative population being studied. The number and volume of FLAIR hyperintense discrete foci were assessed through an edge-finding tool based on local thresholding that was applied to each axial section to identify discrete foci contours. Manual adjustments were applied where necessary. The maximum width or length of each hyperintense focus and the anterior hyperintense capping of the ventricles were assessed with a measurement tool. Hyperintense areas not well suited to quantitative analysis, such as diffuse white matter hyperintensity, septal hyperintensity,4 corticospinal tract hyperintensity,4 and ventricular CSF flow artifacts,12 were qualitatively described. Statistical Analysis The Spearman rank correlation analysis was used to assess the relationship between FLAIR discrete hyperintense foci number or volume and age. Wilcoxon signed rank test was used to assess the difference between age and discrete hyperintense foci detectability on the 1.5 and 3T platforms. A modified Wilcoxon test13 for clustered data was used to assess the difference between discrete hyperintense foci length on the 1.5 and 3T platforms. The Choi test14 assessed the differences between correlations on the 1.5T versus 3T platform. For all analysis, a P value < .05 was considered statistically significant in this exploratory study. [I]If becomes difficult to resolve what your mri findings mean, suggest you consult Penny Sneed MD @ UCSF whose specialty of 35 yrs is the diagnosing and treatment of brain mets from breast cancer. Thoughtful, forthright, no-nonsense and reassuring to those "thinking" the worst. I learned from her that sometimes it is better to go with the older technology 1.5 vs 3T brain MRI and FLAIR is often "normal".