OBJECTIVE:To explore the potential of a post-processing technique combining FLAIR and T2* (FLAIR*) to distinguish between lesions caused by multiple sclerosis (MS) from cerebral small vessel disease (SVD) in a clinical setting.
METHODS:FLAIR and T2* head datasets acquired at 3T of 25 people with relapsing MS (pwRMS) and ten with pwSVD were used. After post-processing, FLAIR* maps were used to determine the proportion of white matter lesions (WML) showing the ‘vein in lesion’ sign (VIL), a characteristic histopathological feature of MS plaques. Sensitivity and specificity of MS diagnosis were examined on the basis of >45% VIL+ and >60% VIL+ WML, and compared with current dissemination in space (DIS) MRI criteria.
RESULTS:All pwRMS had >45% VIL+ WML (range 58-100%) whilst in pwSVD the proportion of VIL+ WML was significantly lower (0-64%; mean 32±20%). Sensitivity based on >45% VIL+ was 100% and specificity 80% whilst with >60% VIL+ as the criterion, sensitivity was 96% and specificity 90%. DIS criteria had 96% sensitivity and 40% specificity.
CONCLUSION:FLAIR* enables VIL+ WML detection in a clinical setting, facilitating differentiation of MS from SVD based on brain MRI.
• FLAIR* in a clinical setting allows visualization of veins in white matter lesions.
Fluid-attenuated inversion recovery (FLAIR) is a pulse sequence used in magnetic resonance imaging. The pulse sequence is an inversion recovery technique that nulls fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the periventricular hyperintense lesions, such as multiple sclerosis (MS) plaques.
T2 is defined as a time constant for the decay of transverse magnetization arising from natural interactions at the atomic or molecular levels. (Don’t worry I can’t understand this either:-) used as a measurement of those processes contributing to the transverse decay of the MR signal that arise from natural interactions at the atomic and molecular levels within the tissue or substance of interest. In any real experiment, however, the transverse magnetization decays much faster than would be predicted by natural atomic and molecular mechanisms; this rate is denoted T2* (“T2-star”). T2* can be considered an “observed” or “effective” T2, whereas the first T2 can be considered the “natural” or “true” T2 of the tissue being imaged. T2* is always less than or equal to T2.
T2* results principally from inhomogeneities in the main magnetic field. These inhomogeneities may be the result of intrinsic defects in the magnet itself or from susceptibility-induced field distortions produced by the tissue or other materials placed within the field.
Whilst the CCSVIers were shouting its all about the veins, so was DrK, but this time using yet another imaging sequence, which is used to detect blood vessels at the heart of MS lesion. This may help in MS diagnosis.