11/30/2023 0 Comments Spike definition mriThis usually occurs at the contacts between the door and the jam and may need to be cleaned or repaired If the artifact persists despite all nearby electronic equipment being turned off, it is possible that the RF shielding is compromised Remove all electronic devices from the patient prior to imaging Make sure the MR scanner room-door is shut during imaging mobile devices or aircraft) and are being picked by the receiver chain of imaging sub-systems. The zipper artifacts that can be controlled easily are those that occur when the door is open during the acquisition of images due to RF entering the scanning room from electronic equipment (e.g. Other equipment and software problems can cause similar zipper-like artifacts in either axis. If multiple frequencies, then multiple bands will be present. If the signal is of only one frequency then only one band will occur. The result is an abnormal black and white signal band across the entire image corresponding to that frequency. These artifacts can be related to hardware or software problems either of the scanner itself or the shielding.Ī common cause is spurious radio-frequency signals contaminating received imaging data. In this instance, the direction in which the artifact is seen depends on the direction in which frequency is encoded and will appear at right angles to the frequency encoding direction. Our study suggests that the independent focal SEW activity remaining ipsilateral to the MRI lesion can potentially predict better surgical prognosis in symptomatic LGS or LG phenotypes.Zipper artifacts are a type of MRI artifact where one or more spurious bands of electronic noise extends across the image. There are various causes for zipper artifacts in images and no single solution exists. Contradictory lateralization difference between MRI and EEG probably arises from the relative voltage attenuation presenting in EEG ipsilateral to huge destructive lesions from early life. Conclusions: Our study reveals a special SEW EEG pattern in symptomatic LG patients with asymmetric SSW and MRI lesions contralateral to the dominant EEG patterns. Predominantly diffuse destructive lesions led to an attenuated voltage of ipsilateral scalp EEG producing an asymmetric SSW pattern in those patients with symptomatic LGS or LG phenotypes. Asymmetric SSW patterns with maximal discharges contralateral to MRI lesions were frequently observed in most of symptomatic LGS or LG phenotypes. The LGS patients with both asymmetric SSW and focal sporadic epileptic waves (SEW) patterns showed the best surgical outcome with Engel class I level. The most common etiology was intracerebral hemorrhage. Results: In this cohort, most of lesions were perinatal or acquired during the first 6 months of life. Methods: Twenty-four symptomatic LGS cases with asymmetric EEG SSW patterns and contralaterally independent or contralaterally dominant MRI lesions were collected, and their clinical features were analyzed retrospectively. This study is aim to ascertain the clinical characteristics of the EEG patterns, and its relationship with MRI lesions and to evaluate its prognostic value of surgical treatment in symptomatic LGS or LG phenotypes. Due to the contradictory lateralization difference between MRI lesions and EEG pattern in symptomatic LGS or LG phenotypes, it is difficult to determine the precise lateralization of epileptic lesions, which is crucial to better surgical prognosis. However, electroencephalogram (EEG) patterns of symptomatic LGS or LG phenotypes with structural brain lesions including focal abnormalities or asymmetric slow-spike-wave (SSW) patterns remain largely unknown. Introduction: Lennox-Gastaut syndrome (LGS) is a severe subtype of childhood-onset epileptic encephalopathy with drug-resistant and poor surgical prognosis.
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