signal changes
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2021 ◽  
Author(s):  
Seung Myung Wi ◽  
Sang-Min Park ◽  
Sam Yeol Chang ◽  
Jeongik Lee ◽  
Sung-Min Kim ◽  
...  

2021 ◽  
pp. 168-170
Author(s):  
M. Tariq Bhatti ◽  
Eric R. Eggenberger ◽  
Marie D. Acierno ◽  
John J. Chen

A 27-year-old man noted imbalance and staggering when walking. Vertigo, nausea, vomiting, and mild fever developed. This was presumed to be due to an inner ear infection, and antibiotics were prescribed. He began experiencing intermittent left face and arm numbness, bilateral hearing loss and tinnitus. Audiography indicated low-frequency hearing loss in both ears, left worse than right. He reported headaches and neck stiffness, and his family noticed that he was moody, easily aggravated, and confused, with slow mentation. Magnetic resonance imaging showed patchy, nodular, leptomeningeal enhancement involving both cerebral hemispheres and the posterior fossa, with scattered hyperintense T2 signal changes of the internal capsule and prominent abnormal signal changes in the corpus callosum. Cerebrospinal fluid analysis was remarkable for a markedly increased protein concentration and white blood cells. Eye examination showed 20/20 vision in both eyes with a superior visual field defect in the right eye. Retinal whitening was noted in the vascular distribution of the inferotemporal arcade. Intravenous fluorescein angiography showed delayed filling in this region consistent with a branch retinal artery occlusion and scattered areas of arteriolar wall hyperfluorescence. A diagnosis of Susac syndrome was made on the basis of the branch retinal artery occlusion, magnetic resonance imaging findings, and hearing deficit. Intravenous methylprednisolone was given, followed oral prednisone, which resulted in substantial improvement in headaches and cognition. Cyclophosphamide was also started at the same time as intravenous methylprednisolone. A new visual field defect developed due to a branch retinal artery occlusion in the left eye, which prompted initiation of intravenous immunoglobulin and transition from cyclophosphamide to rituximab. He had no recurrent branch retinal artery occlusions or other relapses of his underlying Susac syndrome on this treatment regimen. Susac syndrome was initially described as a microangiopathy of the brain and retina. It is an idiopathic autoimmune disorder that primarily affects the brain, eye, and inner ear.


2021 ◽  
Vol 8 ◽  
Author(s):  
Fei Peng ◽  
Tian Zheng ◽  
Xiaoping Tang ◽  
Qiao Liu ◽  
Zijing Sun ◽  
...  

Texture analysis (TA) is a newly arisen field that can detect the invisible MRI signal changes among image pixels. Myocardial infarction (MI) is cardiomyocyte necrosis caused by myocardial ischemia and hypoxia, becoming the primary cause of death and disability worldwide. In recent years, various TA studies have been performed in patients with MI and show a good clinical application prospect. This review briefly presents the main pathogenesis and pathophysiology of MI, introduces the overview and workflow of TA, and summarizes multiple magnetic resonance TA (MRTA) clinical applications in MI. We also discuss the facing challenges currently for clinical utilization and propose the prospect.


2021 ◽  
Vol 12 ◽  
Author(s):  
Gregor Broessner ◽  
Isabel Ellerbrock ◽  
Mareike M. Menz ◽  
Florian Frank ◽  
Michael Verius ◽  
...  

Voxel-based morphometry (VBM) is a widely used tool for studying structural patterns of brain plasticity, brain development and disease. The source of the T1-signal changes is not understood. Most of these changes are discussed to represent loss or possibly gain of brain gray matter and recent publications speculate also about non-structural changes affecting T1-signal. We investigated the potential of pain stimulation to ultra-short-term alter gray matter signal changes in pain relevant brain regions in healthy volunteers using a longitudinal design. Immediately following regional nociceptive input, we detected significant gray matter volume (GMV) changes in central pain processing areas, i.e. anterior cingulate and insula cortex. However, similar results were observed in a control group using the identical time intervals but without nociceptive painful input. These GMV changes could be reproduced in almost 100 scanning sessions enrolling 72 healthy individuals comprising repetitive magnetization-prepared rapid gradient-echo (MPRAGE) sequences. These data suggest that short-term longitudinal repetitive MPRAGE may produce significant GMV changes without any intervention. Future studies investigating brain plasticity should focus and specifically report a consistent timing at which time-point during the experiment the T1-weighted scan is conducted. There is a necessity of a control group for longitudinal imaging studies.


2021 ◽  
Vol 11 (10) ◽  
Author(s):  
Matthew Ricks ◽  
Vasantha Kumar Ramsingh ◽  
Andrew Cole ◽  
George Cox

Introduction:Focal myositis is a rare condition first described by Heffner et al., in 1977, as a self-limiting condition of unknown aetiology. It presents as an inflammatory pseudo tumour in skeletal muscle and can present diagnostic difficulty, being commonly mistaken for tissue of vascular, inflammatory, or neoplastic origin. Diagnosis is traditionally confirmed by muscle biopsy. We present a case where magnetic resonance imaging (MRI) was used to confirm the diagnosis without need for biopsy. Case Presentation: A 19-year year-old female presented with a two2-year history of intermittent swelling of the deltoid associated with pain and tenderness to palpation. . There was no history of trauma or systemic illness. . She was symptomatic with pain, swelling, and tenderness over the left deltoid with no restriction in range of movement of the shoulder or neck. Plain radiographs were normal and MRI magnetic resonance imaging showed diffuse odeamatousedematous signal changes on the proton density weighted sequence within the deltoid muscle and no plexiform neurofibroma. Nerve conduction and electromyography studies were within normal limits excluding an axillary nerve lesion. The patient underwent extensive screening for connective tissue disorders and creatine kinase and lactate dehydrogenase levels were within limits. The patient underwent neuromuscular specialist review confirming that this appeared to be a rare case of focal myositis in the deltoid. . The serial MRI scans confirmed resolution of the condition. Conclusion: Focal myositis of the deltoid is a rare cause of shoulder pain. . We have shown that sequential MRI scanning can obviate the need for muscle biopsy, which has historically been required for diagnostic confirmation. The MRI appearance on the proton density weighted sequence showed diffuse odeamatousedematous signal changes and no plexiform neurofibroma within the deltoid and is a description that has not been previously used for this rare diagnosi


Author(s):  
Heba M. Abou El Atta ◽  
Amal Abdelsattar Sakrana ◽  
Haytham Shebel

Abstract Background Acute renal obstruction due to stone is a prevalent scenario. The diffusion-weighted magnetic resonance imaging (DWI) of the kidneys provides a noninvasive information on renal function. Our objective is to prospectively assess the potential role of DWI to predict the signal changes of a kidney with acute calcular obstruction. Results Chi-square and Fissure exact tests were used to assess the association of diffusion signal changes among patients and control groups. Cohen's Kappa test was run to determine the degree of agreement between the two radiologists. An independent sample t-test was performed to assess the significant difference among ADC values between the two groups. Restricted signals of the obstructed kidneys showed a statistically significant difference when compared with contralateral unobstructed kidney and control group with p value (0.001) and (0.01), respectively. Furthermore, there is a moderate agreement between the two radiologists K = 0.7, p = 0. 001. There is no statistically significant difference in ADC values when comparing the obstructed kidney and the contralateral unobstructed kidney of the patient group or with the control group p value (0.06) and (0.05), respectively. Conclusion Restricted signals of the obstructed kidney by DWI may be a helpful tool in diagnosing acute unilateral renal obstruction and can affect its management; however, it needs further validation by more studies.


2021 ◽  
Vol 429 ◽  
pp. 117871
Author(s):  
Marcelo Barbosa ◽  
Luciana Pimentel-Silva ◽  
Mateus Henrique Nogueira ◽  
Thiago Rezende ◽  
Clarissa Yasuda ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Iichiro Osawa ◽  
Eito Kozawa ◽  
Sayuri Tanaka ◽  
Akane Kaizu ◽  
Kaiji Inoue ◽  
...  

Abstract Background Non-contrast FLAIR revealed increased signal within the inner ear in patients with vestibular schwannoma, which is generally assumed to occur in the perilymph; however, the majority of previous studies did not differentiate between the endolymph and perilymph. Therefore, endolymph signal changes have not yet been investigated in detail. The purpose of the present study was three-fold: (1) to assess perilymph signal changes in patients with vestibular schwannoma on heavily T2-weighted (T2W) 3D FLAIR, also termed positive perilymphatic images (PPI), (2) to evaluate signal and morphological changes in the endolymph on PPI, and (3) to establish whether vertigo correlates with the signal intensity ratios (SIR) of the vestibular perilymph or vestibular endolymphatic hydrops. Methods Forty-two patients with unilateral vestibular schwannoma were retrospectively recruited. We semi-quantitatively and qualitatively evaluated the perilymph signal intensity on the affected and unaffected sides. We also quantitatively examined the signal intensity of the vestibular perilymph and assessed the relationship between vertigo and the SIR of the vestibular perilymph on the affected side. We semi-quantitatively or qualitatively evaluated the endolymph, and investigated whether vestibular hydrops correlated with vertigo. Results The perilymph on the affected side showed abnormal signal more frequently (signal intensity grade: overall mean 1.45 vs. 0.02; comparison of signal intensity: overall mean 36 vs. 0 cases) and in more parts (the entire inner ear vs. the basal turn of the cochlea and vestibule) than that on the unaffected side. No significant difference was observed in the SIR of the vestibular perilymph with and without vertigo (5.54 vs. 5.51, p = 0.18). The endolymph of the vestibule and semicircular canals showed the following characteristic features: no visualization (n = 4), signal change (n = 1), or vestibular hydrops (n = 10). A correlation was not observed between vestibular hydrops and vertigo (p = 1.000). Conclusions PPI may provide useful information on signal and morphological changes in the endolymph of patients with vestibular schwannoma. Further research is warranted to clarify the relationship between vertigo and the MR features of the inner ear.


2021 ◽  
Author(s):  
Murat Kayabekir

As part of the biological rhythm, the human brain has a healthy functioning with the ability to differentiate between day and night hours in any given day (sleep rhythm, life rhythm). From the control of hormone levels to muscle tonus, from the regulation of respiratory rate to the content of our thoughts, sleep has an impact on all bodily and cognitive functions. It is not surprising to see such effects of sleep on the body as it leads to significant changes in the electrical activity of the brain in general. Electrical signal changes in the brain (sleep-wakefulness rhythm) are regulated by neurohormonal molecules and their receptors in the body. Neurotransmitters that control sleep and wakefulness can be listed as “Glutamate, Acetylcholine, Histamine, Norepinephrine and GABA”. Main hormones are: Melatonin, Corticotropin Releasing Hormone (CRH), cortisol, prolactin, Growth Hormone (GH), Insulin like Growth Factor (IGF-1, Somatomedin-C), Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH), progesterone, estrogen, testosterone, catecholamines, leptin and neuropeptide Y″. The effects of pharmacological agents on sleep and wakefulness cycles are materialized through the following molecules and their receptors: Hypnotics (GABA A agonists, benzodiazepines, gabapentin, tiagabine), sedative antidepressants (tricyclic antidepressants, trazadone, mitrazapine), antihistamines, medications used for the treatment of sleeplessness (melatonin and melatonin analogues), amphetamine (most commonly used stimulant), secretion of monoamines (dopamine), non-amphetamine stimulants used in the treatment of hypersomnia and narcolepsy (modafinil, bupropion, selegiline, caffeine) and other substances (alcohol, nicotine, anesthetics). To the extent we can conceptualize the physiological mechanisms of these basic molecules listed above and the regions they affect, we can appreciate the effects of these substances on sleep physiology and sleep disorders.


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