Neuroimaging in concussion
Brian Sindelar, Julian E. Bailes in Sports-Related Concussion, 2017
Unlike CT, cMRI is usually performed in the subacute and chronic settings when postconcussive symptoms persist for weeks or months after the injury. Compared to CT imaging, MRI provides increased sensitivity for detecting structural abnormalities but remains insensitive, even in symptomatic patients. Indeed, 43% to 68% of mild TBI patients show no abnormality by cMRI.10,11 A conventional MRI study for head injury typically includes T1-weighted and T2-weighted fast spin echo sequences, fluid attenuated inversion recovery (FLAIR), and a heme-sensitive sequence such as T2*-weighted gradient echo sequence/gradient recovery echo (GRE). Susceptibility weighted imaging (SWI) is another heme-sensitive sequence, which is even more sensitive to blood products compared to GRE sequences, especially in smaller lesions.12
Basics of CT Scan Head and Trauma Radiographs
Kajal Jain, Nidhi Bhatia in Acute Trauma Care in Developing Countries, 2023
DAI results from traumatic deceleration injury with shearing and rotational forces causing microstructural neuronal transection in areas of greater density differential in the brain, e.g. grey–white matter interface, dorsal brainstem and corpus callosum. It can be either haemorrhagic (Figure 29.6) or non-haemorrhagic (the latter is more common), and may be CT occult when the lesions are very small and subtle. Lesion number and location predicts prognosis (worst when multiple and in supratentorial location). MRI with susceptibility-weighted imaging is suggested when there is a clinical CT discorrelation, i.e. when the latter is apparently normal while the patient is severely affected.
Neuroimaging
John W. Scadding, Nicholas A. Losseff in Clinical Neurology, 2011
Gradient echo or susceptibility weighted imaging depend on local field inhomogeneities from paramagnetic substances, such as iron or gadolinium contrast media, and the signal loss they cause. These sequences show blood products not readily visible on other sequences and are particularly important in acute stroke imaging. Susceptibility effects induced by an infused bolus of gadolinium contrast medium form the basis of perfusion weighted imaging. Arterial spin labelling is a perfusion imaging technique that does not require injected contrast medium. Moving protons in arterial blood are ‘labelled’ and a territorial map of brain perfusion can be made by labelling individual arteries.
High signal-intensity abnormalities in susceptibility-weighted imaging for primary intracerebral hemorrhage
Published in International Journal of Neuroscience, 2019
Jing-Jing Liang, Lu Lei, Yan-Ping Zeng, Zhe-Man Xiao
Susceptibility-weighted imaging (SWI) is an MRI technique that enhances image contrast by using susceptibility differences between the adjacent brain parenchyma [7–10]. SWI is considered to be more sensitive than other multimodal MRI techniques, including conventional MRI and gradient-recalled echo pulse sequences, as it detects the paramagnetic effects of blood products, such as deoxyhemoglobin, methemoglobin, hemosiderin, and ferritin, which are present in a hematoma at different stages [7]. According to this principle, SWI has been applied to image various pathologies, including ICH, microbleeds, calcification, vascular malformation, traumatic brain injury, stroke, neoplasm, and multiple sclerosis [5,11,12], and can help better evaluate the underlying pathophysiology and etiology of ICH. SWI has gradually been adopted into routine clinical imaging within the past decade.
A systematic review of neuroimaging findings in children and adolescents with sports-related concussion
Published in Brain Injury, 2018
Emilie Chamard, Jonathan D. Lichtenstein
Interestingly, some studies have used multiple imaging techniques to investigate the impact of SRC in adolescents (33,34). Bartnik-Olsen and colleagues (34) used conjointly MRS and DTI, as well as PWI, and found a spectrum of injury including impaired axonal function, neuronal metabolism, and perfusion. The authors associated these injuries with the involvement of the ‘neurovascular unit’ (defined by the authors by the physiological relationship between neuronal networks, blood vessels, and glia) in the presence of persistent symptoms in pediatric patients with SRC (34). Another study used these two techniques in addition to susceptibility weighted imaging (SWI), a technique that exploits the magnetic susceptibility differences of various tissues, such as blood, iron, and calcification, as a new source of contrast enhancement (96). While no differences were found with MRS and DTI, differences in Cerebral Blood Flow (CBF) values persisted after resolution of symptoms in athletes with concussion; the authors suggested that a single pediatric SRC produces a state of physiologic disruption rather than a structural or metabolic injury (33). Studies using multiple neuroimaging techniques are particularly interesting as they offer complementary information regarding the pathophysiology of a concussion. However, it remains unclear if the changes observed with different methods correlate together and or if they follow the same course of recovery.
Mechanisms of COVID-19-induced cerebellitis
Published in Current Medical Research and Opinion, 2022
Mohammad Banazadeh, Sepehr Olangian-Tehrani, Melika Sharifi, Mohammadreza Malek-Ahmadi, Farhad Nikzad, Nooria Doozandeh-Nargesi, Alireza Mohammadi, Gary J. Stephens, Mohammad Shabani
Some COVID-19 patients show evidence of cerebellar infarction and lesions32; for example, MRI examination in a study on patients with acute ischemic stroke and COVID-19 showed acute infarcts in the right cerebellar hemisphere and acute left posterior inferior cerebellar artery territory infarction with petechial hemorrhage33. Moreover, in MRI of a patient with COVID-19, T2 lesions were seen in the right cerebellum34. In other studies, MRIs of axial T2 showed irregular signal changes in the cerebellar vermis and left cerebellar hemisphere due to posterior circulation infarctions35. In one study, injuries to the left cerebellar hemisphere were confirmed by MRI36. This study demonstrated acute and subacute infarcts using susceptibility-weighted imaging (SWI), an MRI procedure exquisitely sensitive to venous blood, hemorrhage, and iron storage. The same study confirmed multiple microhemorrhages in the left cerebellar hemisphere36. Moreover, brain MRI using gadolinium showed multiple acute ischemic infarctions in the regions of the left posterior inferior cerebellar artery, involving the left cerebellar hemisphere and the cerebellar vermis35.
Related Knowledge Centers
- Diffuse Axonal Injury
- Diffusion Mri
- Traumatic Brain Injury
- Oxygen Saturation
- Multiple Sclerosis
- Mri Sequence
- Pulse Sequence
- Blood-Oxygen-Level-Dependent Imaging
- Sturge–Weber Syndrome
- Fluid-Attenuated Inversion Recovery