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A patient after a major head trauma showing diffuse axonal injury with small hemorrhagic lesions in the medial part of both thalami (arrows, a) and multiple lesions near the cortico-subcortical junction (arrowheads, a and b) seen as hypointensity on gradient-echo-weighted imaging (a and b). Multiple additional lesions can be seen on SWI imaging (c and d) demonstrating the superiority of SWI imaging in diffuse axonal injury.
Source publication
Background:
Thalamic lesions are seen in a multitude of disorders including vascular diseases, metabolic disorders, inflammatory diseases, trauma, tumours, and infections. In some diseases, thalamic involvement is typical and sometimes isolated, while in other diseases thalamic lesions are observed only occasionally (often in the presence of other...
Citations
... 13,14 Transient edema or inflammation may account for the complete resolution of some lesions observed in imaging, particularly in patients with a history of seizures or epilepsy. Investigations involving patients with prolonged status epilepticus have revealed thalamic DWI and FLAIR hyperintensities on the same side as the epileptiform activity, 15,16 often ill-defined signal within the pulvinar. 17 Thalamic involvement has also been associated with venous vasculitis conditions, such as Behcet disease, or connective tissue disorders, such as Sjogren syndrome. ...
... 17 Thalamic involvement has also been associated with venous vasculitis conditions, such as Behcet disease, or connective tissue disorders, such as Sjogren syndrome. 15 These lesions often appear hyperintense in T2 and FLAIR sequences and occasionally exhibit enhancement in gadolinium-enhanced T1-weighted imaging. 15 Finally, these lesions may represent isolated dysplastic or hamartomatous changes of the thalamus, such as in cases of NF1 12,18 (although no subject in our study had this diagnosis). ...
... 15 These lesions often appear hyperintense in T2 and FLAIR sequences and occasionally exhibit enhancement in gadolinium-enhanced T1-weighted imaging. 15 Finally, these lesions may represent isolated dysplastic or hamartomatous changes of the thalamus, such as in cases of NF1 12,18 (although no subject in our study had this diagnosis). ...
Background and purpose:
Nonspecific, localized thalamic signal abnormalities of uncertain significance are occasionally found on pediatric brain MR imaging. The goal of this study is to describe the MR imaging appearance and natural history of these lesions in children and young adults.
Materials and methods:
This retrospective study evaluated clinically acquired brain MR imaging examinations obtained from February 1995 to March 2022 at a large, tertiary care pediatric hospital. Examinations with non-mass-like and nonenhancing thalamic lesions were identified based on term search of MR imaging reports. A total of 221 patients formed the initial group for imaging assessment. Additional exclusions during imaging review resulted in 171 patients. Imaging appearance and size changes were assessed at baseline and at follow-up examinations.
Results:
A total of 171 patients (102 male) at a median age of 11 years (range: 1-23 years), 568 MR imaging examinations, and 180 thalamic lesions were included. Median time from baseline to the last follow-up MR imaging was 542 days (range: 46-5730 days). No lesion enhanced at any time point. On imaging follow-up, 11% of lesions (18/161) became smaller, 10% (16/161) resolved, 73% (118/161) remained stable, and 6% (9/161) increased in size at some point during evaluation. Median time interval from baseline to enlargement was 430 days (range: 136-1074 days).
Conclusions:
Most incidental, non-mass-like thalamic signal abnormalities were stable, decreased in size, or resolved on follow-up imaging and are likely of no clinical significance. Surveillance strategies with longer follow-up intervals may be adequate in the management of such findings.
... [75] Thalamus calcifications, which include toxic, are caused by infectious diseases such as tuberculosis, HIV, and cytomegalovirus. [76] The involvement of the corpus callosum in COVID-19 is believed to be related to the potential effect of the cytokine storm [77] that is a life-threatening systemic inflammatory syndrome involving elevated levels of circulating cytokines and immune-cell hyperactivation. [78] Newcombe et al. (2020) reported a significant FA reduction in corona radiata fibers in COVID-19 patients compared to non-COVID-19 controls. ...
Coronavirus disease 2019 (COVID-19) is an epidemic viral disease caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the excessive number of neurological articles that have investigated the effect of COVID-19 on the brain from the neurological point of view, very few studies have investigated the impact of COVID-19 on the cerebral microstructure and function of the brain. The aim of this study was to summarize the results of the existing studies on cerebral microstructural changes in COVID-19 patients, specifically the use of quantitative volumetric analysis, blood oxygen level dependent (BOLD), and diffusion tensor imaging (DTI). We searched PubMed/MEDLINE, ScienceDirect, Semantic Scholar, and Google Scholar from December 2020 to April 2022. A well-constructed search strategy was used to identify the articles for review. Seven research articles have met this study's inclusion and exclusion criteria, which have applied neuroimaging tools such as quantitative volumetric analysis, BOLD, and DTI to investigate cerebral microstructure changes in COVID-19 patients. A significant effect of COVID-19 was found in the brain such as hypoperfusion of cerebral blood flow, increased gray matter (GM) volume, and reduced cortical thickness. The insula and thalamic radiation were the most frequent GM region and white matter tract, respectively, that are involved in SARS-CoV-2. COVID-19 was found to be associated with changes in cerebral microstructures. These abnormalities in brain areas might lead to be associated with behaviors, mental and neurological alterations that need to be considered carefully in future studies.
... With increasing knowledge of different functions of thalamic neurons, the key role of the thalamus in cognition, working memory, learning, and in decision-making is being increasingly recognized. [7][8][9][10][11] The nontraumatic thalamic diseases can be of the following pathologies: 1. Vascular lesions-stroke 2. Metabolic diseases-osmotic demyelination syndrome 3. Reversible posterior encephalopathy syndrome 4. Nondemyelinating inflammatory disease-vasculitis (e.g.,-Behcet disease), or connective disease (e.g., Sjogren syndrome) 5. Neoplastic-Glioblastoma, metastatic deposits 6. Infections -brain abscess, viral encephalitides (Japanese encephalitis, dengue virus), multifocal leukoencephalopathy 7. Post infective demyelinating diseases -steroid responsive 8. Degenerative disease -Creutzfeldt-Jakob disease (CJD), thalamic dementia [12,13] ...
... Papez circuit is important for the registration and retrieval of short-term memory (Kirshner and Kistler). [8,13] Patients with fluent aphasia were also described following dominant thalamic lesions. [11] Thalamic pain, numbness, and hemisensory loss ...
Introduction: Thalamus is an oval mass of gray matter between the third ventricle and the internal capsule. The medial, spinal, and trigeminal lemnisci are the great ascending sensory projections from the periphery. The lateral and medial geniculate bodies transmit the visual and auditory information to the cortex. The thalamus also contains motor projections from the basal ganglia, on their way to the motor cortex and supplementary motor area. Materials and Methods: Over 2-year period from November 2015 onward, 83 patients with magnetic resonance imaging confirmed nontraumatic thalamic lesions were identified, and followed up. The patient population consisted of adults above 18 years of age. They were investigated as to the cause of the lesion and treated. Results: There were 58 male patients, 25 female patients. Stroke was the major cause while less common diseases causing thalamic lesions were demyelination, tumor, calcification, and gliosis. The lesions were more common on the left side. The extent of thalamic involvement was global (50.6%) most commonly. The next common was posteromedial affection (18.1%) and dorsal thalamus (14.5%). Corresponding motor weakness (57.8%) was the most common symptom, though other symptoms such as sensory loss (30.1%), ataxia (27.7%), memory loss (12%), and gaze paresis (30.1%) were also present. Headache (31.3%) and giddiness (24%) were less common than motor weakness. Speech disturbance was seen in 49.4% of patients. Discussion: Stroke is unilateral disease, while venous thrombosis, demyelination, tumor, metabolic diseases and infection can affect thalami bilaterally. While stroke can explain the sudden onset of sensory and motor disturbances, some features like cognitive dysfunction were difficult to explain. A transient disorientation to time can follow acute anterior thalamic lesions. Some patients had language disturbances suggesting that the language dominance can extend down up to thalamus. Chronic pain can also be due to a gliotic lesion in the thalamus. Upward gaze palsy seen in a third of our patients could be due to global thalamic or due to medial longitudinal fasciculus involvement. Two patients had visual hemineglect. Sleep disturbances could also be observed in thalamic disease. Asterixis and hemifacial spasm were not seen in our patients. Three patients with strokes had brachial onset seizures, and one patient had generalized seizures. Different types of gait disturbances were observed in thalamic disease including ataxia, astasia-abasia, and hemiparetic gait. Conclusion: The most common thalamic lesion was an ischemic stroke, followed by bleed. Global thalamic involvement was more common than other partial lesions, though posteromedial and dorsal lesions are also commonly seen. Sensorimotor dysfunction is the most common clinical presentation and less frequent presentations include aphasia, memory disturbances, behavioral, and cognitive dysfunction. Movement disorders, ataxic gait, sleep disturbances, and infrequently, seizures were seen in our series.
... In such setting, it is important to note that computerized tomographic scans which is the main imaging modality used in acute ischemic stroke settings may not identify these infarction when done within the first 24 hours and whenever thalamic infarcts are suspected, magnetic resonance imaging if available will be a better imaging choice 33 . Apart from the diagnosis of acute infarctions the other differentials include tumor and venous infarcts [34][35] which may also be detected by magnetic resonance imaging. The most common vascular territory involved in our series, constituting 77.3% of thalamic infarctions was the ventrolateral (thalamogeniculate) arteries. ...
... Notably, the frequency of pulvinar injuries was significantly higher in the combined BGT-WS group (25.1% versus only 6.2% in isolated BGT), 17.7% of which were not associated with any BG lesion (grey circle in Figs. 2 and 4). There are several pathologies in the paediatric population that could have a predilection for thalamic pulvinars, such as stroke involving the posterior choroidal arteries, Fabry's disease, 15 and CreutzfeldteJakob disease variants 16 ; however, it is neonatal hypoglycaemia, described as the commonest metabolic disorder seen in neonates, 17 that should be listed as the primary cause of pulvinar injury in the setting of a underlying WS pattern of HII. ...
AIM
To compare frequency and distribution of deep nuclei involvement in isolated basal ganglia and ventrolateral thalamus (BGT) versus combined BGT and watershed (BGT-WS) hypoxic–ischaemic injury (HII).
MATERIALS AND METHODS
A retrospective review was undertaken of the magnetic resonance imaging (MRI) reports of children (0–18 years) with isolated BGT or combined BGT-WS HII. The location and extent of deep nuclear injuries were compared between groups using Fisher's exact test.
Results
Of 762 MRI reports, 435 (57%) had isolated BGT and 327 (43%) combined BGT-WS. Isolated BGT showed basal ganglia involvement in 85.1% (n=370) versus 49.8% (n=163) for combined BGT-WS (p<0.01). Sole putamen lesions were more common in isolated BGT (70.3%; 306) versus combined (19.3%; 63; p<0.01). Thalamic involvement was similar between isolated BGT (93.8%; 408) and combined BGT-WS (96.9%; 317; p>0.05). Sole ventrolateral nucleus involvement was more common in isolated BGT (66.6%; 291) while sole pulvinar lesions (25.1%; 82) and whole thalamus lesions (41.6%; 136) were more common in combined BGT-WS (p<0.01). Putamen and ventrolateral nucleus was the most frequent BGT lesion combination in isolated BGT (55.4%) but not in combined BGT-WS (8.6%; p<0.01).
CONCLUSION
Variations in the frequency of deep nuclear lesions between groups may reflect different underlying pathogenetic mechanisms. Therefore, combined BGT-WS patterns may not necessarily indicate a superimposed profound on partial prolonged HII, as other causes such as neonatal hypoglycaemia may cause these.
... Extrapontine myelinolysis, due to changes in osmotic gradient, may lead to thalamic lesions (along with lesions involving the basal ganglia, cerebellum, cerebral white matter, and hippocampus), which appear hyperintense on T2/FLAIR, hypointense on T1 and hyperintense on DWI with heterogeneous signal on ADC [14]. ...
The acute confussional state is one of the most common reasons for neurologic consultation in the hospital setting and the plethora of causes can truly be daunting. The etiology can vary from structural, metabolic, toxic to systemic infections.
Our purpose is to present a rare case of acute confussional state in a patient with bilateral thalamic ischemic stroke due to occlusion of the artery of Percheron (AOP).
A 79-year-old woman with a history of hypertension and surgery for lumbar disc herniation, managed on antiplatelet therapy, angiotensin receptor blocker and diuretics, was admitted for acute confusion and paresthesia of all four limbs. She had disorientation in time and space, abnormal behavior, decreased muscle strength in both lower limbs (paraparesis 2/5 MRC since the surgery), paresthesia in all four limbs and was unable to walk due to generalized weakness. Laboratory analysis showed high blood levels of cholesterol and glucose.
Both head CT and cerebral MRI showed bilateral ischemic changes in the thalami, suggesting an infarct along the artery of Percheron territory. However, no clear cause for the stroke could be identified. Screening for coagulation abnormalities and autoimmune disorders (lupus anticoagulant, anti-beta-2 glycoprotein, anti-cardiolipin, anti-nuclear and anti-ds DNA antibodies) came
back negative. There were no pathological finds on the echocardiogram and electrocardiogram, while cervical Doppler ultrasound showed atherosclerosis without stenosis.
... Furthermore, this supply varies individually. For example, in one-third of the population, the tuberothalamic artery is absent, with its territory instead supplied by the paramedian artery [4]. This underlies the basis of the rare nature of bilateral thalamic strokes; such strokes only represented 0.6% of all ischemic strokes in a study involving 2750 patients [5]. ...
A 90-year-old male patient presented with excessive somnolence, right-sided weakness, and left facial droop. CT and MRI scans of the head, taken several days after initial head CT proved to be non-revealing, demonstrated a bilateral thalamic stroke, a rare phenomenon. The infarct arose in the territory of the artery of Percheron, an anatomic variant in which a single artery supplies both sides of the thalamus and midbrain. When this artery becomes occluded, it results in severely dysregulated consciousness and alertness. This type of stroke proved challenging for the medical team, due to poor resolution of initial imaging, as well as the therapy teams, due to the constant need for sleep. This case report outlines how barriers in diagnosis and management make knowledge of the artery of Percheron and its occlusion crucial to patient care and recovery.
... Although exceptional, bithalamic involvement (seen as T2/FLAIR hyperintense lesions) can be displayed in MS. Identifying concurrent typical demyelinating MS lesions is essential for the diagnosis (Fig. 7) [14]. ...
... Imaging features partly overlap with MS, however with thalamic and basal ganglia involvement being more frequent in ADEM. Differentiation amongst the two is aided by the monophasic postinfectious/postvaccination nature of ADEM and by simultaneous enhancement seen in ADEM lesions [14]. However, absence of enhancement does not exclude the diagnosis. ...
The aim of this pictorial review is to familiarize radiologists with the numerous pathologies that can affect bilateral thalami while demonstrating their several neuroimaging manifestations. Vascular etiologies include infarcts of the artery of Percheron, tip of the basilar syndrome, venous infarcts, hypoxic-ischemic encephalopathy, PRES, hypertensive microbleeds, and CADASIL; infectious etiologies include Creutzfeldt-Jakobs disease and encephalitides, while demyelinating disorders include ADEM and MS. Bilateral thalamic involvement may also be seen in metabolic & toxic etiologies such as Wernicke encephalopathy, osmotic myelinolysis, Fabry disease, Fahr disease, Wilson disease, and Leigh disease. Furthermore, low- and high-grade gliomas may originate or infiltrate bilateral thalami while gadolinium deposition can be a mimicker of disease. Radiological features that can be used in the assessment and differential approach include MR signal characteristics, calcifications, exact location within the thalamus, symmetry, presence of synchronous extra-thalamic involvement, and presence of expansion. Additional imaging tools such as DWI, MRA/MRV/CTA/CTV, MRS, PWI, and correlation with clinical and laboratory findings may narrow the differential diagnosis.
... A total of 1,179 patients with abnormal diffusion-weighted imaging (DWI), which was finished 7 days after admission to the Inpatient Department of Dalian Municipal Central Hospital, were screened between January 2013 and December 2014. Pure thalamic infarct was confirmed by DWI with an ischemic region restricted to four groups of the thalamic blood supply territory (1,4,5). Exclusion criteria were partial or total top of the basilar syndrome and a combination of thalamic and other anterior circulation territories. ...
Pure thalamic infarct is a rare lacunar stroke type, with little known about long-term outcomes. This 8-year, single-center, retrospective study evaluated the clinical background, etiology, Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification, and 8-year follow-up results in 27 patients with pure thalamic infarcts identified by MR diffusion-weighted imaging in Dalian, China. All patients presented chief complaints of limb weakness or sensory disturbances. Hypertension (24/27, 88.9%), diabetes (12/27, 44.4%), atrial fibrillation (1/27, 3.7%), hyperlipidemia (10/27, 37%), hyperhomocysteinemia (6/27, 22.2%), smoking history (10/27, 37%; 9/15, 60% for men; 1/12, 8.3% for women), and excessive alcohol consumption history (7/27, 25.9%; 7/15, 46.7% for men; 0 for women) were observed in our patient population. Based on TOAST classification, 1 patient had large artery atherosclerosis (7.14%), 23 had small vessel occlusion (SVO; 85.2%), and 3 patients were unidentified due to lack of cerebral angiography. The thalamic blood supply classification were as follows: 23 (85.2%), inferolateral territory; 1 (3.7%), tuberothalamic territory; 2 (7.4%), combination of tuberothalamic and paramedian arteries; 1 (3.7%), combination of inferolateral and paramedian arteries; 0, posterior choroidal arteries. During the 8-year follow-up, 3 patients died of colon cancer, multi-organ failure, and kidney failure, respectively; 7 presented with a recurrent stroke; while 10 recovered well with their risk factors under control. In conclusion, our cohort of pure thalamic infarcts were mainly due to SVO (TOAST), with hypertension as the main risk factor, and the inferolateral artery as the most implicated arterial territory. Less severe outcome or stroke recurrence are identified in long-term follow-up of pure thalamic infarcts. Other comorbidities would be cause of death in aged patients.
... The topography of thalamic blood flow is displayed below in Figure 2 The image is reprinted under the Creative Commons Attribution License. Source: [12] The general outline is that the anterior territory is supplied by the tubero-thalamic arteries, the paramedian territory from the paramedian arteries, the inferolateral territory from the thalamo-geniculate arteries and the posterior territories from the posterior choroidal arteries. ...
... [12]. ...
The thalamus is a complex structure with over 40 named nuclei. Ischemic lesions of the thalamus exhibit a panorama of phenomena ranging from facial numbness to ocular and visual field disturbances to hemiplegia, behavioral disorders, and stupor. It is a dense neuronal hub with a bewildering variety of connections and functions. We present an intriguing case of intermittent vertical diplopia due to an artery of Percheron ischemic infarct of the bilateral paramedian thalami. We seize upon this opportunity to simplify the thalamic nuclei subdivisions and their vascular supply. In this process, we outline the phenotypic variability of thalamic diplopia and ophthalmoplegia and their various underlying mechanisms.
