Brainstem Stroke: Anatomy, Clinical and Radiological Findings

Assessment of corticospinal tract damage and cytokines response in early and late stages of acute unilateral brainstem infarction patients

Background

Acute brainstem infarction is associated with high morbidity and mortality, the integrity of corticospinal tract (CST) detected via diffusion tensor imaging (DTI) can assist in predicting the motor recovery of the patients. In addition to the damage caused by ischemia and reperfusion, sterile inflammation also contributes to the brain injury after stroke. However, the changes in CST integrity detected by DTI in acute brainstem infarction have yet to be fully elucidated, and it is still unclear whether sterile inflammation can cause damage to the CST.

Methods

In this study, the acute brainstem infarction patients in the early (EABI patients, n = 19) and late (LABI patients, n = 21) stages and healthy controls (HCs, n = 22) are employed. The probabilistic tractography technique was used and the fractional anisotropy (FA) value was chosen to evaluated the integrity of the CST, the IL-6, IL-10, IL-17, IL-1β, and tumor necrosis factor (TNF)-α levels in the plasma are measured to evaluate the level of inflammation.

Results

Compared to the HCs (F = 13.634, p ANOVA < 0.001), the CST FA values on the infarcted side were abnormally elevated in EABI patients (p LSD = 0.003), and decreased in LABI patients (p LSD = 0.034). The levels of IL-6 (F = 12.311, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD < 0.001), IL-10 (F = 11.329, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD = 0.017) and IL-1β (F = 15.986, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD < 0.001) were increased in both EABI and LABI patients, while the IL-17 levels were elevated only in LABI patients (F = 4.258, p ANOVA = 0.019, LABI vs HCs: p LSD = 0.027). Among these cytokines, the increased IL-6 (r = 0.663, p = 0.002) and IL-1β (r = 0.615, p = 0.005) levels of EABI patients might be related to the elevated CST FA values, while the increased IL-17 (r = -0.599, p = 0.004) levels of LABI patients might contribute to the decrease of the CST FA values.

Conclusion

Our study reveals that the increased CST FA values in EABI patients may include signals generated by the immune cells which move along the CST. The sterile inflammation may contribute to the impairment of CST integrity in LABI patients.

Eight-and-a-Half Syndrome Secondary to Acute Brainstem Infarction

Eight-and-a-half syndrome is a rare neuro-ophthalmologic condition, which is characterized by ipsilateral horizontal gaze palsy, internuclear ophthalmoplegia (INO), and ipsilateral lower motor neuron facial palsy. We report a case of eight-and-a-half syndrome secondary to acute brainstem infarction. A 55-year-old gentleman with underlying diabetes mellitus and hypertension presented with a sudden onset of double vision in the right lateral gaze for one day. On examination, there was a limitation in the left eye horizontal eye movement with limited right eye adduction. Further neurological examination revealed left lower motor neuron facial nerve palsy. Magnetic resonance imaging (MRI) of the brain showed an acute infarct involving the left side of the thalamus extending to the left side of the midbrain, pons, and medulla. He was diagnosed with eight-and-a-half syndrome secondary to acute brainstem infarction. The patient was referred to the neuromedical team, where he was treated with anti-platelet medications. He showed gradual improvement on follow-up and had complete resolution of ophthalmoplegia after three months. There was only minimal residual facial nerve weakness. Eight-and-a-half syndrome has a localizing value to the dorsal tegmentum of the pons. It requires thorough neurological examination and imaging studies for accurate diagnosis and management. This case highlights the potential for a significant recovery in patients with eight-and-a-half syndrome when timely and appropriate treatment is administered.

Challenges in radiological evaluation of brain metastases, beyond progression

MRI is the cornerstone in the evaluation of brain metastases. The clinical challenges lie in discriminating metastases from mimickers such as infections or primary tumors and in evaluating the response to treatment. The latter sometimes leads to growth, which must be framed as pseudo-progression or radionecrosis, both inflammatory phenomena attributable to treatment, or be considered as recurrence. To meet these needs, imaging techniques are the subject of constant research. However, an exponential growth after radiotherapy must be interpreted with caution, even in the presence of results suspicious of tumor progression by advanced techniques, because it may be due to inflammatory changes. The aim of this paper is to familiarize the reader with inflammatory phenomena of brain metastases treated with radiotherapy and to describe two related radiological signs: "the inflammatory cloud" and "incomplete ring enhancement", in order to adopt a conservative management with close follow-up.

Presentation of basilar artery stroke secondary to patent foramen ovale: a diagnosis made with a 'selfie'

We report the case of a woman in her late 20s, with no significant medical history, who was found unresponsive at home. Her mother revealed a 'selfie' sent to her by the patient 30 min prior to collapse which revealed bilateral ptoses. Initial brain imaging with non-contrast CT of the brain revealed nil of note. A multiphase CT angiogram revealed an acute basilar artery thrombosis. She underwent timely thrombolysis and was transferred for endovascular thrombectomy. Further evaluation with an aim to define the aetiology revealed the diagnosis of patent foramen ovale with a resultant paradoxical embolism. The differential diagnoses of unexplained rapidly evolving neurology with reduced Glasgow coma scale, and relevant appropriate investigations are discussed in this case report.

Rescue Endovascular Treatment to Prevent Neurological Deterioration in Acute Symptomatic Bilateral Vertebral Artery Occlusion

Bilateral vertebral artery occlusive disease has been considered as a favorable condition with good collaterals. However, the prognosis of acute ischemic stroke secondary to symptomatic bilateral vertebral artery occlusion (BVAO) and endovascular treatment (EVT) has rarely been reported. We retrospectively selected patients with acute ischemic stroke admitted for symptomatic BVAO between January 2020 and February 2023. All patients with ischemic stroke were evaluated for ischemic lesion and arterial status using brain imaging and angiography. The prognosis of acute stroke with symptomatic BVAO was compared between EVT and conventional treatment. Outcomes were evaluated using modified Rankin Scale (mRS) score at 3 months follow-up. Within the study period, 17 of 2,655 acute ischemic stroke patients were diagnosed with ischemic stroke with symptomatic BVAO. The median age of these patients was 70 (interquartile range 44-89) years, and 13 (76%) were male. Seven patients received emergent EVT with stenting and 10 patients received conventional medical treatment only. Nine of 10 patients with conventional treatment had in-hospital stroke progression and developed new ischemic lesions in the pons and midbrain. Five patients with fetal and hypoplastic posterior communicating artery presented bilateral cerebral peduncular lesions. At 3 months follow-up, 6 patients (35%) had favorable outcomes (mRS 0-2), of which 5 were treated with vertebral artery stenting and 1 received conventional treatment. Ischemic stroke in patients with acute symptomatic BVAO is uncommon. However, stroke progression is common, and the prognosis of most patients is poor. Rescue management such as EVT might be considered for symptomatic BVAO.

The value of computed tomography perfusion deficit volumes in acute isolated brainstem infarction

Purpose

Diagnosis of acute isolated brainstem infarction is challenging owing to non-specific, variable symptoms, and the effectiveness of non-contrast computed tomography (NCCT) is poor owing to limited spatial resolution and artifacts. Computed tomography perfusion (CTP) imaging parameters are significantly associated with functional outcomes in posterior circulation acute ischemic stroke; however, the role of CTP in isolated brainstem infarction remains unclear. We aimed to determine the value of CTP imaging parameters in predicting functional outcomes for affected patients.

Methods

In total, 116 consecutive patients with isolated pontine/midbrain hypoperfusion who underwent CTP and follow-up by magnetic resonance imaging (MRI) between January 2018 and March 2022, were retrospectively analyzed. Perfusion deficit volumes on all maps, and the final infarction volume (FIV) on MRI were quantified. "Good" functional outcome was defined as a 90-day modified Rankin Scale score of 0 and 1. Statistical analysis included uni- and multivariate regression analyses, binary logistic regressions, and receiver operating characteristics (ROC) analyses.

Results

In total, 113 patients had confirmed isolated pontine/midbrain infarction on follow-up MRI. Onset-to-scan time, visibility of ischemic lesions on NCCT, the baseline National Institutes of Health Stroke Scale (NIHSS) score, and perfusion deficit volumes on all CTP maps were significantly associated with FIV (p < 0.05). In a multivariate linear regression model, adjusted for age, sex, NIHSS score, onset-to-scan time, and visibility of NCCT, perfusion deficit volumes remained significantly associated with FIV. In binary logistic regression analyses, perfusion deficit volumes on all CTP maps remained independent predictors of a good functional outcome. In ROC analyses, the cerebral blood flow deficit volume showed a slightly higher discriminatory value with the largest area under the curve being 0.683 [(95% CI, 0.587-0.780), p = 0.001].

Conclusion

Perfusion deficit volumes of CTP imaging could reflect the FIV and contain prognostic information on functional outcomes in patients with acute isolated brainstem infarction.

Integrative Approaches in Acute Ischemic Stroke: From Symptom Recognition to Future Innovations

Among the high prevalence of cerebrovascular diseases nowadays, acute ischemic stroke stands out, representing a significant worldwide health issue with important socio-economic implications. Prompt diagnosis and intervention are important milestones for the management of this multifaceted pathology, making understanding the various stroke-onset symptoms crucial. A key role in acute ischemic stroke management is emphasizing the essential role of a multi-disciplinary team, therefore, increasing the efficiency of recognition and treatment. Neuroimaging and neuroradiology have evolved dramatically over the years, with multiple approaches that provide a higher understanding of the morphological aspects as well as timely recognition of cerebral artery occlusions for effective therapy planning. Regarding the treatment matter, the pharmacological approach, particularly fibrinolytic therapy, has its merits and challenges. Endovascular thrombectomy, a game-changer in stroke management, has witnessed significant advances, with technologies like stent retrievers and aspiration catheters playing pivotal roles. For select patients, combining pharmacological and endovascular strategies offers evidence-backed benefits. The aim of our comprehensive study on acute ischemic stroke is to efficiently compare the current therapies, recognize novel possibilities from the literature, and describe the state of the art in the interdisciplinary approach to acute ischemic stroke. As we aspire for holistic patient management, the emphasis is not just on medical intervention but also on physical therapy, mental health, and community engagement. The future holds promising innovations, with artificial intelligence poised to reshape stroke diagnostics and treatments. Bridging the gap between groundbreaking research and clinical practice remains a challenge, urging continuous collaboration and research.

A Case of Comorbid Weber Syndrome Following Mechanical Thrombectomy for Middle Cerebral Artery Occlusion

Background

In Weber syndrome, one side of the cerebral peduncle of the midbrain is infarcted due to the occlusion of the interpeduncular branch of the posterior cerebral artery and the posterior choroidal artery, resulting in ipsilateral oculomotor nerve palsy and contralateral hemiparesis. However, Weber syndrome induced by simple anterior choroidal artery lesions has rarely been reported.

Case Description

Computed tomographic angiography revealed occlusion of the left internal carotid artery in a 57-year-old male patient who was admitted to the Beijing Haidian Hospital with cerebral infarction. Thrombectomy to clear the occlusion of the left internal carotid artery and the middle cerebral artery was successfully performed in the emergency department. However, postoperative digital subtraction angiography indicated occlusion of the middle and distal segments of the left anterior choroidal artery. After recovery from anesthesia, the patient had left blepharoptosis, inability to abduct the left eye, limitation of the upward and downward gaze, left mydriasis, absence of response to light, and right hemiplegia. Complete head magnetic resonance imaging suggested left cerebral peduncle and basal ganglia infarction. Therefore, the diagnosis was that the patient had left Weber syndrome caused by a left anterior choroidal arterial embolism.

Conclusion

When the anterior choroidal artery is the dominant supplier of blood to the medial region of the ipsilateral cerebral peduncle, the occlusion of this artery may lead to ipsilateral Weber syndrome.

Symptoms of Myasthenia Gravis Obscured by Old Age and Unilateral Presentation

Myasthenia gravis (MG) is a neuromuscular junction disorder involving autoantibodies affecting the postsynaptic muscle membrane. We report an 81-year-old man who presented to the emergency department with three days of left facial droop, who later developed worsening bilateral ptosis, cervical weakness, dysphagia, and dysarthria following an assessment for Bell's palsy. Ultimately, he was diagnosed with MG. This patient's presentation was atypical and challenging. Specifically, the patient had droopy eyelids from a redundancy of skin and an anatomical neck droop, non-specific findings in older adults, which obscured the development of bilateral ptosis and cervical weakness, a classic sign of bulbar disease. The patient also presented with unilateral facial weakness, a rare finding in MG and concerning stroke in the elderly population. Our aim is to discuss the challenges of identifying MG in older populations and to discuss pharmacological challenges in assessing elderly patients with suspected bulbar palsies.

A New Neurological Screening Approach for Diagnosing Brainstem Infarction Using the Calling Method and Familiar Voices

This report proposes a new approach to assess dysarthria in patients with brainstem infarction by involving familiar individuals. Collaboration provides valuable insights compared to subjective traditional methods. A man in his 70s presented with resolved positional vertigo. Standard neurological tests showed no abnormalities, and inquiries with the patient's friend did not reveal voice changes. While inquiring about voice changes with family, friends, and acquaintances is a common practice in clinical settings, our approach involved the patient calling out to his friend from a distance. Despite the physician detecting no abnormalities, the friend noticed a lower voice. Subsequent magnetic resonance imaging (MRI) confirmed brainstem infarction. Early and subtle symptoms of brainstem infarction pose a detection challenge and can lead to serious outcomes if overlooked. This report provides the first evidence that distance calling can detect subtle voice changes associated with brainstem infarction potentially overlooked by conventional neurological examinations, including inquiries with individuals familiar with the patient's voice. Detecting brainstem infarction in emergency department cases is often missed, but conducting MRIs on every patient is not feasible. This simple method may identify patients overlooked by conventional screening who should undergo neuroimaging such as MRI. Further research is needed, and involving non-professionals in assessments could significantly advance the diagnostic process.

Neuroimaging in Coma, Brain Death, and Related Conditions

Coma is a state of unresponsiveness to external stimuli, which can be secondary to a variety of CNS alterations affecting essential neuronal pathways, particularly the ascending reticular activating system. A comprehensive clinical evaluation is necessary for assessment of motor function and brainstem reflexes but is often insufficient for determination of the underlying etiology and extent of injury. Diagnostic brain imaging is typically needed for management and decision-making, particularly in acute settings where prompt diagnosis of reversible/treatable conditions is essential, as well as for prognostication. Understanding the pathophysiologic mechanisms leading to coma and comalike states and their imaging manifestations will enable selection of appropriate modalities and facilitate a clinically relevant interpretation. For evaluation of brain death, diagnostic imaging has a supportive role, and when indicated, selection of an ancillary diagnostic test is based on multiple factors, including susceptibility to confounding factors and specificity, in addition to safety, convenience, and availability.Learning objective: To describe the pathophysiology of alterations of consciousness and discuss the role of neuroimaging modalities in the evaluation of coma, brain death, and associated conditions

GABAergic neurons differentiated from BDNF- and Dlx2-modified neural stem cells restore disrupted neural circuits in brainstem stroke

BACKGROUND

Brainstem stroke causes severe and persistent neurological impairment. Due to the limited spontaneous recovery and regeneration of the disrupted neural circuits, transplantation of exogenous neural stem cells (NSCs) was an alternative, while there were limitations for primitive NSCs.

METHODS

We established a mouse model of brainstem stroke by injecting endothelin in the right pons. Brain-derived neurotrophic factor (BDNF)- and distal-less homeobox 2 (Dlx2)-modified NSCs were transplanted to treat brainstem stroke. Transsynaptic viral tracking, immunostaining, magnetic resonance imaging, behavioral testing, and whole-cell patch clamp recordings were applied to probe the pathophysiology and therapeutic prospects of BDNF- and Dlx2-modified NSCs.

RESULTS

GABAergic neurons were predominantly lost after the brainstem stroke. No endogenous NSCs were generated in situ or migrated from the neurogenesis niches within the brainstem infarct region. Co-overexpressions of BDNF and Dlx2 not only promoted the survival of NSCs, but also boosted the differentiation of NSCs into GABAergic neurons. Results from transsynaptic virus tracking, immunostaining, and evidence from whole-cell patch clamping revealed the morphological and functional integration of the grafted BDNF- and Dlx2-modified NSCs-derived neurons with the host neural circuits. Neurological function was improved by transplantation of BDNF- and Dlx2-modified NSCs in brainstem stroke.

CONCLUSIONS

These findings demonstrated that BDNF- and Dlx2-modified NSCs differentiated into GABAergic neurons, integrated into and reconstituted the host neural networks, and alleviated the ischemic injury. It thus provided a potential therapeutic strategy for brainstem stroke.

Diagnostic values of leukocyte, neutrophil, and neutrophil to lymphocyte ratio in distinguishing central facial paralysis from peripheral facial paralysis

OBJECTIVE

Misdiagnosis of central facial palsy (CFP) as peripheral facial palsy (PFP) can lead to serious consequences clinically. It is unknown whether the leukocyte counts (leukocyte), neutrophil counts (neutrophil), and neutrophil to lymphocyte ratio (NLR) can be used to distinguish CFP from PFP.

METHODS

Of the total 152 patients admitted for acute facial paralysis, 76 CFP patients (CFP group) caused by acute ischemic stroke (AIS) and 76 PFP cases (PFP group) without AIS were enrolled in this retrospective study. The levels of blood leukocyte, neutrophil, lymphocyte, platelet counts (platelet), NLR, and platelet to lymphocyte ratio (PLR) before or upon admission were recorded and compared between the two groups. The student t-test was adopted for comparison of the mean. Model discrimination was evaluated using the area under the receiver operating characteristic curve (AUC). Comparison of AUC was performed using the Z-test.

RESULTS

Compared with PFP group, the levels of leukocyte, neutrophil, and NLR were significantly increased in CFP group (all p < 0.01), and there were still significantly statistical differences (all p < 0.01), even after adjusting for age, gender, and past medical history, while no significantly statistical differences of lymphocyte, platelet, and PLR were found between CFP and PFP (all p > 0.05); furthermore, the AUC in distinguishing CFP from PFP were 0.629, 0.671, and 0.657 for leukocyte, neutrophil, and NLR, respectively, and no significant difference of AUC was observed among leukocyte, neutrophil, and NLR (p > 0.05); finally, the cutoff values (specificity, sensitivity, and Youden index) in distinguishing CFP from PFP were 7.08 × 10⁹/L (65.79%, 57.89%, 0.237) for leukocyte, 4.90 × 10⁹/L (73.68%, 60.53%, 0.342) for neutrophil, and 2.88 (72.37%, 55.26%, 0.276) for NLR, respectively.

CONCLUSIONS

As easy-to-obtain and inexpensive inflammatory biomarkers, leukocyte, neutrophil, and NLR could demonstrate diagnostic values in distinguishing between CFP and PFP.

Management of Complications in Vestibular Schwannoma Surgery

Microsurgical removal of acoustic neuroma has advanced tremendously; however, complications still occur. Facial nerve injury is the most common detrimental complication and should take precedence over gross tumor removal in cases where there is an unfavorable tumor-facial nerve interface. Cerebrospinal fluid leakage can occur even with meticulous closure techniques and is generally treatable with either lumbar-subarachnoid drainage or revision wound closure. Meningitis is a serious complication that requires a high index of suspicion in the postoperative period. Other less common complications include intraoperative and postoperative vascular injuries. Early identification and treatment can prevent devastating outcomes.

Strong Contrast Stagnation of Unilateral Vertebral Artery on Three-Dimensional Black Blood-Enhanced MRI Predicts Acute Medulla Infarction

PURPOSE

This study aimed to evaluate angiographic and contrast enhancement (CE) patterns on three-dimensional (3D) black blood (BB) contrast-enhanced MRI in patients with acute medulla infarction.

MATERIALS AND METHODS

From January 2020 to August 2021, we retrospectively analyzed stroke 3D BB contrast-enhanced magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) findings of patients visiting the emergency room for symptom evaluation of acute medulla infarction. In total, 28 patients with acute medulla infarction were enrolled in this study. Four types of 3D BB contrast-enhanced MRI and MRA were classified as follows: 1=unilateral contrast-enhanced vertebral artery (VA)+no visualization of VA on MRA; 2=unilateral enhanced VA+hypoplastic VA; 3=no enhanced VA+unilateral complete occlusion of VA; 4=no enhanced VA+normal VA (including hypoplasia) on MRA.

RESULTS

Of the 28 patients with acute medulla infarction, 7 (25.0%) showed delayed positive findings after 24 hours on diffusion-weighted imaging (DWI). Of these patients, 19 (67.9%) showed CE of the unilateral VA on 3D BB contrast-enhanced MRI (type 1 and 2). Of the 19 patients with CE of VA on 3D BB contrast-enhanced MRI, 18 showed no visualization of enhanced VA on MRA (type 1), and 1 showed hypoplastic VA. Of the 7 patients with delayed positive findings on DWI, 5 showed CE of the unilateral VA and no visualization of the enhanced VA on MRA (type 1). Symptom onset to door time or initial MR check time was significantly shorter in the groups with delayed positive findings on DWI (P<0.05).

CONCLUSION

Unilateral CE on 3D BB contrast-enhanced MRI and no visualization of the VA on MRA are related to the recent occlusion of the distal VA. These findings suggest that the recent occlusion of the distal VA is related to acute medulla infarction, including delayed visualization on DWI.

A radiomics feature-based machine learning models to detect brainstem infarction (RMEBI) may enable early diagnosis in non-contrast enhanced CT

OBJECTIVES

Magnetic resonance imaging has high sensitivity in detecting early brainstem infarction (EBI). However, MRI is not practical for all patients who present with possible stroke and would lead to delayed treatment. The detection rate of EBI on non-contrast computed tomography (NCCT) is currently very low. Thus, we aimed to develop and validate the radiomics feature-based machine learning models to detect EBI (RMEBIs) on NCCT.

METHODS

In this retrospective observational study, 355 participants from a multicentre multimodal database established by Huashan Hospital were randomly divided into two data sets: a training cohort (70%) and an internal validation cohort (30%). Fifty-seven participants from the Second Affiliated Hospital of Xuzhou Medical University were included as the external validation cohort. Brainstems were segmented by a radiologist committee on NCCT and 1781 radiomics features were automatically computed. After selecting the relevant features, 7 machine learning models were assessed in the training cohort to predict early brainstem infarction. Accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1-score, and the area under the receiver operating characteristic curve (AUC) were used to evaluate the performance of the prediction models.

RESULTS

The multilayer perceptron (MLP) RMEBI showed the best performance (AUC: 0.99 [95% CI: 0.96-1.00]) in the internal validation cohort. The AUC value in external validation cohort was 0.91 (95% CI: 0.82-0.98).

CONCLUSIONS

RMEBIs have the potential in routine clinical practice to enable accurate computer-assisted diagnoses of early brainstem infarction in patients with NCCT, which may have important clinical value in reducing therapeutic decision-making time.

KEY POINTS

• RMEBIs have the potential to enable accurate diagnoses of early brainstem infarction in patients with NCCT. • RMEBIs are suitable for various multidetector CT scanners. • The patient treatment decision-making time is shortened.

Locked-in syndrome revisited

The locked-in syndrome (LiS) is characterized by quadriplegia with preserved vertical eye and eyelid movements and retained cognitive abilities. Subcategorization, aetiologies and the anatomical foundation of LiS are discussed. The damage of different structures in the pons, mesencephalon and thalamus are attributed to symptoms of classical, complete and incomplete LiS and the locked-in plus syndrome, which is characterized by additional impairments of consciousness, making the clinical distinction to other chronic disorders of consciousness at times difficult. Other differential diagnoses are cognitive motor dissociation (CMD) and akinetic mutism. Treatment options are reviewed and an early, interdisciplinary and aggressive approach, including the provision of psychological support and coping strategies is favoured. The establishment of communication is a main goal of rehabilitation. Finally, the quality of life of LiS patients and ethical implications are considered. While patients with LiS report a high quality of life and well-being, medical professionals and caregivers have largely pessimistic perceptions. The negative view on life with LiS must be overthought and the autonomy and dignity of LiS patients prioritized. Knowledge has to be disseminated, diagnostics accelerated and technical support system development promoted. More well-designed research but also more awareness of the needs of LiS patients and their perception as individual persons is needed to enable a life with LiS that is worth living.

Acute Onset Quadriplegia and Stroke: Look at the Brainstem, Look at the Midline

Acute onset quadriplegia with or without facial sparing is an extremely rare vascular syndrome, and the main focus of attention is on the cervical and upper thoracic spinal cord as the putative site of the damage. Quadriplegia has been occasionally reported in brainstem strokes within well-defined lesion patterns, but these reports have gained little attention so far because of the rarity of this clinical syndrome. The clinical, neuroanatomical and neuroimaging features of ischemic stroke locations associated with quadriplegia have been collected and reviewed in a pragmatical view, which includes a detailed description of the neurological signs associated with the damage of the pyramidal pathways. Two clinical examples have been added to raise practical suggestions in neurovascular practice. Ischemic stroke sites determining quadriplegia have some main well-defined midline locations in the brainstem, involving the pyramidal pathways of both sides in a single synchronous ischemic lesion in the medulla oblongata and in the pons. Several accompanying neurological signs have been described when the ischemic lesion involves tracts and nuclei other than the pyramidal pathways, and they can be useful as localizing clues. In some cases, the typical neuroimaging appearance of the ischemic lesion on Magnetic Resonance Imaging (MRI) has been reported as being a "heart appearance sign". This last sign has been described in midbrain strokes too, but this location is not associated with quadriplegia. The main etiology is atherothrombosis involving the intradural segment of the vertebral artery (VA) and their perforating branches. Two clinical examples of these rare vascular syndromes have been chosen to support a pragmatical discussion about the management of these cases. A midline ischemic stroke in the brainstem is a very rare vascular syndrome, and the acute onset quadriplegia is a distinctive feature of it. The awareness of this cerebrovascular manifestation might help to recognize and treat these patients.

Systematic review and meta-analysis of acupuncture in the treatment of cognitive impairment after stroke

BACKGROUND

We aim to make a systematic evaluation of the clinical efficacy of acupuncture in the treatment of cognitive impairment after stroke, to provide evidence-based medical evidence for clinical practice.

METHODS

We searched all the randomized controlled trials of China National Knowledge Infrastructure, Wan fang data knowledge service platform, VIP Chinese periodical service platform full-text Journal Database, Chinese Biomedical Literature Database, Cochrane Library Database, and PubMed Database about acupuncture treatment of post-stroke cognitive impairment (PSCI). Two researchers independently screened the literature and extracted the data according to the inclusion and exclusion criteria. The bias risk assessment manual of Cochrane collaboration Network was used to evaluate the bias risk, and all data were analyzed by Stata16.0.

RESULTS

Fourteen articles were included, with a total of 2402 patients. Meta-analysis showed that acupuncture combined with routine therapy could significantly reduce the score of cognitive impairment symptoms compared with the control group. The mini-mental state examination scale (MMSE) score (weighted mean difference [WMD] = 3.23, 95% confidence interval [CI]: 1.89-4.56, P < .01), Montreal cognitive assessment scale (MoCA) score (WMD = 3.41, 95% CI: 0.93-5.89, P < .01), Barthel index of activities of daily living (MBI) score (WMD = 4.59, 95% CI: 1.43-7.75, P < .01), and Lowenstein assessment scale (LOTCA) score (WMD = 8.60, 95% CI: 6.32-10.89, P = .00) were significantly improved in the patients receiving group acupuncture combined with routine therapy.

CONCLUSION

Acupuncture combined with routine therapy seems to be more effective than conventional therapy alone in the treatment of PSCI. However, the differences between different acupuncture types need to be clarified in more high-quality randomized controlled trials.

MRI-Visible Anatomy of the Brainstem

Human brainstem internal anatomy is intricate, complex, and essential to normal brain function. The brainstem is affected by stroke, multiple sclerosis, and most neurodegenerative diseases-a 1-mm focus of pathologic condition can have profound clinical consequences. Unfortunately, detailed internal brainstem anatomy is difficult to see with conventional MRI sequences. We review normal brainstem anatomy visualized on widely available clinical 3-T MRI scanners using fast gray matter acquisition T1 inversion recovery, probabilistic diffusion tractography, neuromelanin, and susceptibility-weighted imaging. Better anatomic localization using these recent innovations improves our ability to diagnose, localize, and treat brainstem diseases. We aim to provide an accessible review of the most clinically relevant brainstem neuroanatomy.

Diagnostic Value of Image Features of Magnetic Resonance Imaging in Intracranial Hemorrhage and Cerebral Infarction

This study aimed to investigate the differential diagnosis value of routine magnetic resonance imaging (MRI) and magnetic resonance diffusion-weighted imaging (DWI) in hyperacute intracranial hemorrhage (HICH) and hyperacute cerebral infarction (HCI). Fifty-five patients with HICH were set as group A, and 55 patients with HCI were selected as group B. All the patients underwent routine MRI and DWI examinations. The morphological distribution and signal characteristics (low, high, or mixed) of the lesions in the two groups were recorded. The diagnostic accuracy, sensitivity, and specificity of routine MRI and DWI were compared for distinguishing HICH and HCI. The results suggested that the lesions in patients with HICH were mainly manifested as mixed signals (40 cases), while those in patients with HCI showed high signals (48 cases). HICH occurred in the basal ganglia in 44 cases, in the brain stem in 6 cases, in the cerebellum in 4 cases, in the cerebral cortex in 0 cases, and in the corpus callosum in 1 case. HCI occurred in the basal ganglia area, brain stem, cerebellum, cerebral cortex, and corpus callosum in 5, 3, 35, 12, and 0 cases, respectively. The diagnostic accuracy, specificity, and sensitivity of DWI for HICH and HCI were significantly higher than those of routine MRI (P < 0.05). It was indicated that compared with routine MRI, DWI was more effective in the diagnosis of HICH and HCI, with clearer and more accurate images and better diagnostic performance.

Accidente cerebrovascular isquémico de la arteria cerebral media

La segunda causa de muerte a nivel mundial corresponde a los ataques cerebrovasculares (ACV), de los cuales más de dos terceras partes son de origen isquémico. Causan discapacidad a largo plazo por lo que conocer la anatomía de la circulación cerebral y las posibles manifestaciones clínicas del ACV isquémico permite sospechar, diagnosticar y brindar un manejo oportuno y apropiado, reduciendo el impacto en la salud y la calidad de vida del paciente y sus cuidadores. Objetivo: relacionar los últimos hallazgos en la anatomía arterial cerebral, los mecanismos fisiopatológicos y las manifestaciones clínicas del ACV isquémico de la arteria cerebral media (ACM). Materiales y métodos: revisión de la literatura mediante la búsqueda con términos MeSH en la base de datos Medline, incluyendo estudios, ensayos y metaanálisis publicados entre 2000 y 2020 en inglés y español, además de otras referencias para complementar la información. Resultados: se seleccionaron 59 publicaciones, priorizando la de los últimos 5 años y las más relevantes del rango temporal consultado. Conclusiones: son escasos los estudios sobre la presentación clínica de los ACV, lo que sumado a la variabilidad interindividual de la irrigación cerebral, dificulta la determinación clínica de la localización de la lesión dentro del lecho vascular. La reperfusión del área de penumbra isquémica como objetivo terapéutico se justifica por los mecanismos fisiopatológicos de la enfermedad.

Predicting functional outcome in patients with acute brainstem infarction using deep neuroimaging features

BACKGROUND AND PURPOSE

Acute brainstem infarctions can lead to serious functional impairments. We aimed to predict functional outcomes in patients with acute brainstem infarction using deep neuroimaging features extracted by convolutional neural networks (CNNs).

METHODS

This nationwide multicenter stroke registry study included 1482 patients with acute brainstem infarction. We applied CNNs to automatically extract deep neuroimaging features from diffusion-weighted imaging. Deep learning models based on clinical features, laboratory features, conventional imaging features (infarct volume, number of infarctions), and deep neuroimaging features were trained to predict functional outcomes at 3 months poststroke. Unfavorable outcome was defined as modified Rankin Scale score of 3 or higher at 3 months. The models were evaluated by comparing the area under the receiver operating characteristic curve (AUC).

RESULTS

A model based solely on 14 deep neuroimaging features from CNNs achieved an extremely high AUC of 0.975 (95% confidence interval [CI] = 0.934-0.997) and significantly outperformed the model combining clinical, laboratory, and conventional imaging features (0.772, 95% CI = 0.691-0.847, p < 0.001) in prediction of functional outcomes. The deep neuroimaging model also demonstrated significant improvement over traditional prognostic scores. In an interpretability analysis, the deep neuroimaging features displayed a significant correlation with age, National Institutes of Health Stroke Scale score, infarct volume, and inflammation factors.

CONCLUSIONS

Deep learning models can successfully extract objective neuroimaging features from the routine radiological data in an automatic manner and aid in predicting the functional outcomes in patients with brainstem infarction at 3 months with very high accuracy.

Locked-In Syndrome: A Systematic Review of Long-Term Management and Prognosis

Locked-in syndrome (LIS) is a neurological disorder in which there is damage to the ventral pons and caudal midbrain. An ischemic cause, such as basilar artery occlusion, can often lead to LIS. LIS has three subtypes: classical, partial, and total. There is loss of motion in the four extremities in classical LIS, loss of horizontal gaze, and aphasia. In partial LIS, the patient still has some motor function. Complete LIS has the worst outcome because patients cannot blink or have vertical gaze, thus rendering them incapable of communicating. Most cases of LIS occur due to ischemic infarcts. These patients require a great deal of physical rehabilitation to regain partial motor ability and a means to communicate. While the clinical features and pathophysiology are known, the prognosis and long-term treatment remain unknown. We conducted a systematic review using the Meta-Analysis Of Observational Studies in Epidemiology (MOOSE) protocol. We use an advanced PubMed strategy using the inclusion criteria of observational studies or clinical trials conducted in the last 20 years, written in English, and conducted on humans. We excluded systematic reviews, literature reviews, metanalysis, and studies that did not meet the outcomes of our objectives. The prognosis of LIS is not good, and most patients remain locked in, with poor quality of life, especially motor functions. Respiratory failure and depression are big comorbidities. In the acute setting, patients benefit from rapid intervention. The subacute treatment needs to manage aggressively to improve functional scores best. The long-term treatment focus is on the quality of life and managing comorbidities.

Disrupted brain functional network topology in unilateral acute brainstem ischemic stroke

This study aimed to investigate the topological properties of brain functional connectome in unilateral acute brainstem ischemic stroke using graph theory. Fifty-three acute brainstem ischemic stroke patients, consisted of 27 left-sided and 26 right-sided brainstem stroke patients, and 20 age, gender, and education-matched healthy controls (HCs) were recruited to undergo a resting-state functional magnetic resonance imaging (rs-fMRI) scan in this study. Graph theory analyses were then used to examine the group-specific topological properties of the functional connectomes seperately. The unilateral acute brainstem stroke patients and HCs all exhibited "small-world" brain network topology. The functional connectome of the left brainstem stroke patients showed significant differences in all topological properties while the right brainstem stroke patients showed a significant increase in clustering coefficient Cp (p < 0.001) and local efficiency E_local (p < 0.001), and a significantly decrease in normalized clustering coefficient γ (p < 0.001) and global efficiency E_global (p < 0.001), suggesting both a shift toward regular networks. At the nodal level, abnormal nodal centralities were mainly observed in the defaut mode network, subcortical network, frontal and occipital lobe. The findings of disrupted topological properties of functional brain networks may help better understanding the disease characterization and innovation in management for acute brainstem ischemic stroke patients.

Millard-Gubler Syndrome Associated with Cerebellar Ataxia in a Patient with Isolated Paramedian Pontine Infarction - A Rarely Observed Combination with a Benign Prognosis: A Case Report

Isolated pontine infarction accounts for 7% of all ischemic strokes. Millard-Gubler syndrome is a clinical syndrome which occurs following lesions involving the ventral portion of the caudal pons, resulting in classic clinical features such as ipsilateral abducens and facial nerve palsy and contralateral hemiparesis. We report the case of a 55-year-old male patient having presented to the Yehuleshet Specialty Clinic 6 years back with sudden-onset dysarthria and appendicular ataxia of 10 days duration. He reported having right hemibody weakness and blurred vision, which have significantly improved since then. He had a history of smoking of 30 pack-years. However, he quit smoking 8 years ago. There was no history of prior stroke, transient ischemic attack, diabetes, hypertension, head trauma, or dyslipidemia. On examination, he had horizontal left gaze palsy with horizontal nystagmus suggesting left-sided 6th cranial nerve palsy. He had mild left-sided facial palsy causing dysarthric speech. Right upper limb dysmetria was observed during examination; otherwise, motor, sensory, fundus, and gait examination results were normal. He had low serum vitamin D. Brain magnetic resonance imaging examination showed a 25 × 10 mm segmental lesion in the left median pons involving the basis pontis and tegmentum section. The lesion had T2 and T1 abnormal prolongation with no diffusion restriction, suggesting a subacute pontine infarct. The patient was managed with aspirin 325 mg, atorvastatin 80 mg, physical therapy, and vitamin D supplementation, and advised on behavioral risk factors. Six years after his isolated pontine infarction, the patient is fully recovered from dysarthria, facial palsy, hemiparesis, right-sided appendicular ataxia, and horizontal nystagmus, and the follow-up brain MRI showed radiological evidence of chronic paramedian pontine perforator infarction. Millard-Gubler syndrome may present with cerebellar ataxia if the paramedian pontine infarction area slightly extends laterally, affecting the middle cerebellar peduncles. Isolated pontine infarction may have a good prognosis if diagnosed and managed early.

MRI topography of lesions related to internuclear ophthalmoplegia in patients with multiple sclerosis or ischemic stroke

BACKGROUND AND PURPOSE

Internuclear ophthalmoplegia is a dysfunction of conjugate eye movements, caused by lesions affecting the medial longitudinal fasciculus (MLF). Multiple sclerosis (MS) and ischemic stroke represent the most common pathophysiologies. While magnetic resonance imaging (MRI) allows for localizing lesions affecting the MLF, comprehensive comparative studies exploring potential different spatial characteristics of lesions affecting the MLF are missing until now.

METHODS

We retrospectively investigated MRI examinations of 82 patients (40 patients with MS and 42 patients with ischemic stroke). For lesion localization, the brainstem was segmented into (1) ponto-medullary junction, (2) mid pons, (3) upper pons, and (4) mesencephalon.

RESULTS

Corresponding lesions affecting the MLF were observed in 29/40 (72.5%) MS and 38/42 (90.5%) stroke patients. Compared to stroke patients, MS patients had significantly more lesions in multiple locations (P < .001). Stroke patients showed more lesions at the level of the mesencephalon (P < .001), while lesions at the level of the ponto-medullary junction, mid, and upper pons did not statistically differ between the groups.

CONCLUSION

Our results demonstrate that multiple lesions affecting the MLF make inflammatory-demyelination due to MS more likely, while lesion localization at the level of the mesencephalon favors ischemia.

Alterations of brain network topology and structural connectivity-functional connectivity coupling in capsular versus pontine stroke

BACKGROUND AND PURPOSE

This study was conducted to investigate whether capsular stroke (CS) and pontine stroke (PS) have different topological alterations of structural connectivity (SC) and functional connectivity (FC), as well as correlations of SC-FC coupling with movement assessment scores.

METHODS

Resting-state functional magnetic resonance imaging and diffusion tensor imaging were prospectively acquired in 46 patients with CS, 36 with PS, and 29 healthy controls (HCs). Graph theoretical network analyses of SC and FC were performed. Patients with left and right lesions were analyzed separately.

RESULTS

With regard to FC, the PS and CS groups both showed higher local efficiency than the HCs, and the CS group also had a higher clustering coefficient (Cp) than the HCs in the right lesion analysis. With regard to SC, the PS and CS groups both showed different normalized clustering coefficient (γ), small-worldness (σ), and characteristic path length (Lp) compared with the HC group. Additionally, the CS group showed higher normalized characteristic path length (λ) and a lower Cp than the HCs and the PS group showed higher λ and lower global efficiency than the HCs in the right-lesion analysis. However, γ, σ, Cp and Lp were only significantly different in the PS and CS groups compared with the HC group in the right-lesion analysis. Importantly, the CS group was found to have a weaker SC-FC coupling than the PS group and the HC group in the right-lesion analysis. In addition, both patient groups had weaker structural-functional connectome correlation than the HCs.

CONCLUSIONS

The CS and PS groups both showed FC and SC disruption and the CS group had a weaker SC-FC coupling than the PS group in the right lesion analysis. This may provide useful information for individualized rehabilitative strategies.

Dynamic changes of inflammation and apoptosis in cerebral ischemia‑reperfusion injury in mice investigated by ferumoxytol‑enhanced magnetic resonance imaging

The inflammatory response and apoptosis are key factors in cerebral ischemia-reperfusion injury. The severity of the inflammatory reaction and apoptosis has an important impact on the prognosis of stroke. The ultrasmall superparamagnetic iron oxide particle has provided an effective magnetic resonance molecular imaging method for dynamic observation of the cell infiltration process in vivo. The aims of the present study were to investigate the inflammatory response of cerebral ischemia-reperfusion injury in mice using ferumoxytol-enhanced magnetic resonance imaging, and to observe the dynamic changes of inflammatory response and apoptosis. In the present study a C57BL/6n mouse cerebral ischemia-reperfusion model was established by blocking the right middle cerebral artery with an occluding suture. Subsequently, the mice were injected with ferumoxytol via the tail vein, and magnetic resonance scanning was performed at corresponding time points to observe the signal changes. Furthermore, blood samples were used to measure the level of serum inflammatory factors, and histological staining was performed to assess the number of iron-swallowing microglial cells and apoptotic cells. The present results suggested that there was no significant difference in the serum inflammatory factors tumor necrosis factor-α and interleukin 1β between the middle cerebral artery occlusion (MCAO) and MCAO + ferumoxytol groups injected with ferumoxytol and physiological saline. The lowest signal ratio in the negative enhancement region was decreased 24 h after reperfusion in mice injected with ferumoxytol. The proportion of iron-swallowing microglial cells and TUNEL-positive cells were the highest at 24 h after reperfusion, and decreased gradually at 48 and 72 h after reperfusion. Therefore, the present results indicated that ferumoxytol injection of 18 mg Fe/kg does not affect the inflammatory response in the acute phase of cerebral ischemia and reperfusion. Ferumoxytol-enhanced magnetic resonance imaging can be used as an effective means to monitor the inflammatory response in the acute phase of cerebral ischemia-reperfusion injury. Furthermore, it was found that activation of the inflammatory response and apoptosis in the acute stage of cerebral ischemia-reperfusion injury is consistent.

Delayed Lesions on Diffusion-Weighted Imaging in Initially Lesion-Negative Stroke Patients

Background and Purpose

Lesions on diffusion-weighted imaging (DWI) occasionally appear on follow-up magnetic resonance imaging (MRI) among initially DWI-negative but clinically suspicious stroke patients. We established the prevalence of positive conversion in DWI-negative stroke and determined the clinical factors associated with it.

Methods

This retrospective, observational, single-center study included 5,271 patients hospitalized due to stroke/transient ischemic attack (TIA) in a single university hospital during 2010 to 2017. Patients without initial DWI lesions underwent follow-up DWI imaging as a routine practice. Adjusted hazard ratios (aHRs) for recurrent stroke risk according to positive conversion were determined using Cox proportional hazard regression. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for positive conversion among initially DWI-negative patients were estimated.

Results

In total, 694 (13.2%) patients (mean±standard deviation age, 62.9±13.7 years; male, 404 [58.2%]) were initially DWI-negative. Among them, 22.5% had positive-conversion on follow-up DWI. Positive conversion was associated with a higher risk of recurrent stroke (aHR, 3.12; 95% CI, 1.56 to 6.26). Early neurologic deterioration (aOR, 15.1; 95% CI, 5.71 to 47.66), atrial fibrillation (aOR, 6.17; 95% CI, 3.23 to 12.01), smoking (aOR, 3.76; 95% CI, 2.19 to 6.63), pre-stroke dependency (aOR, 1.62; 95% CI, 1.15 to 2.27), objective hemiparesis (aOR, 4.39; 95% CI, 1.90 to 10.32), longer symptom duration (aOR, 2.17; 95% CI, 1.57 to 3.08), high cholesterol (aOR, 4.70; 95% CI, 1.78 to 12.77), National Institutes of Health Stroke Scale score (aOR, 1.44; 95% CI, 1.08 to 1.91), and high systolic blood pressure (aOR, 1.01; 95% CI, 1.00 to 1.02) were associated with a higher incidence of lesions with delayed appearance. Regarding the location of lesions on follow-up DWI, 34.6% and 21.2% were in the cortex and brainstem, respectively.

Conclusions

In DWI-negative stroke/TIA, positive conversion is associated with a higher risk of recurrent stroke. DWI-negative stroke with factors related to positive conversion may require follow-up MRI for a definitive diagnosis.

A preliminary study of cortical morphology changes in acute brainstem ischemic stroke patients

The study aimed to explore the cortical thickness and gyrification abnormalities in acute brainstem ischemic patients in both the ipsilateral and contralateral hemisphere compared with healthy controls. Structural magnetic resonance imaging data were prospectively acquired in 48 acute brainstem ischemic patients, 21 patients with left lesion and 27 with right lesion, respectively. Thirty healthy controls were recruited. Cortical morphometry based on surface-based data analysis driven by CAT12 toolbox implemented in SPM12 was used to compare changes in cortical thickness and gyrification. Significant decreases of cortical thickness loss were found in bilateral cerebral hemispheres of the brainstem ischemic patients compared to the healthy controls (P < .05, family-wise error (FWE)-corrected). We also found significant gyrification decreases in the insula, transverse temporal, supramarginal of the ipsilateral on hemisphere in the right brainstem ischemic patients compared to the healthy controls (P < .05, FWE-corrected). Brainstem ischemic patients have widely morphological changes in the early phase and may be helpful in designing individualized rehabilitative strategies for these patients.

Clinical presentation of vertebrobasilar stroke

Vertebrobasilar (VB) stroke is responsible for 20% of all strokes and transient ischemic attacks. Due to the vast cerebral territory it supplies, VB ischemia can present with a wide range of symptoms and signs, sometimes even overlapping with carotid circulation stroke. Furthermore, brain computed tomography, usually performed as initial imaging modality, has a suboptimal visualization of the posterior fossa, making VB stroke an even more challenging diagnosis to any physician. Hence, awareness of the vertebrobasilar anatomy and the clinical presentation of VB ischemia is crucial to promote early recognition of this disorder.

Multimodal Computed Tomography Increases the Detection of Posterior Fossa Strokes Compared to Brain Non-contrast Computed Tomography

Aims: Multimodal computed tomography (mCT) (non-contrast CT, CT angiography, and CT perfusion) is not routinely used to assess posterior fossa strokes. We described the area under the curve (AUC) of brain NCCT, WB-CTP automated core-penumbra maps and comprehensive CTP analysis (automated core-penumbra maps and all perfusion maps) for posterior fossa strokes. Methods: We included consecutive patients with signs and symptoms of posterior fossa stroke who underwent acute mCT and follow up magnetic resonance diffusion weighted imaging (DWI). Multimodal CT images were reviewed blindly and independently by two stroke neurologists and area under the receiver operating characteristic curve (AUC) was used to compare imaging modalities. Results: From January 2014 to December 2019, 83 patients presented with symptoms suggestive of posterior fossa strokes and had complete imaging suitable for inclusion (49 posterior fossa strokes and 34 DWI negative patients). For posterior fossa strokes, comprehensive CTP analysis had an AUC of 0.68 vs. 0.62 for automated core-penumbra maps and 0.55 for NCCT. For cerebellar lesions >5 mL, the AUC was 0.87, 0.81, and 0.66, respectively. Conclusion: Comprehensive CTP analysis increases the detection of posterior fossa lesions compared to NCCT and should be implemented as part of the routine imaging assessment in posterior fossa strokes.

Diagnostic benefit of high b-value computed diffusion-weighted imaging in acute brainstem infarction

BACKGROUND AND PURPOSE

Diffusion-weighted imaging (DWI) is a cornerstone in diagnostic of ischemic stroke. The aim of this study was to investigate the usefulness of high-b-value computed DWI (c-DWI) in comparison to standard DWI in patients with acute brainstem infarction.

MATERIALS AND METHODS

56 patients with acute brainstem infarction were retrospectively analysed by two readers. DWI was obtained with the b-values 0, 500 and 1000 s/mm² on either a 1.5 or 3 T magnetic resonance imaging (MRI) scanner. c-DWI was calculated with a monoexponential model with high b-values 2000, 3000, 4000 and 5000 s/mm². All c-DWI series with high-b-values were compared to the standard DWI sequence at b-value of 1000 s/mm² in terms of image artifacts, lesion extent and contrast.

RESULTS

There was no statistically significant difference between 1.5 and 3 T MRI regarding the measured ischemic lesion size. There were no statistically significant differences between the ischemic lesion sizes on DWI at b-values of 1000 s/mm² and on c-DWI at higher b-values. Overall, the contrast between the lesion and the surrounding normal areas improved with increasing b-value on the isotropic DWIs: maximum at b = 5000, followed by that at b 2000 and b 1000 s/mm², in order. The best relation between artifacts and lesion contrast was identified for b 2000 s/mm².

CONCLUSION

High b-value DWI derived from c-DWI has a higher visibility for ischemic brainstem lesions compared to standard DWI without additional time cost. The b-2000 image is recommended to use in clinical routine, higher b-value images lead to more imaging artifacts, which might result in misdiagnosis.

A Focal Pontine Infarct Presenting as Unilateral Facial Nerve Paralysis

Brainstem infarction typically presents with vague symptoms, including headache, nausea, vomiting, and vertigo. Rarely do patients present with complete unilateral facial paralysis, mimicking Bell’s palsy. Here we report the case of a 40-year-old woman who presented to the emergency department with intractable nausea, vomiting, and vertigo upon waking along with left-sided upper and lower extremity numbness and right-sided facial paralysis. Her atypical presentation of unilateral facial nerve paralysis in the context of nausea, vomiting, and vertigo prompted neurological studies, which were significant for a small punctate infarct in the pons involving the right facial colliculus. ​History, physical examination, and clinical suspicion are important to prevent anchoring bias. Physicians rely on history and physical examination to help distinguish true Bell’s palsy from other causes of facial nerve paralysis. Stroke and other clinically emergent etiologies should be considered high on the differential diagnosis when patients have neurological signs and symptoms in addition to facial nerve palsy.

Midbrain, Pons, and Medulla: Anatomy and Syndromes

The anatomy of the brainstem is complex. It contains numerous cranial nerve nuclei and is traversed by multiple tracts between the brain and spinal cord. Improved MRI resolution now allows the radiologist to identify a higher level of anatomic detail, but an understanding of functional anatomy is crucial for correct interpretation of disease. Brainstem syndromes are most commonly due to occlusion of the posterior circulation or mass effect from intrinsic space-occupying lesions. These syndromes can have subtle imaging findings that may be missed by a radiologist unfamiliar with the anatomy or typical manifesting features. This article presents the developmental anatomy of the brainstem and discusses associated pathologic syndromes. Congenital and acquired syndromes are described and correlated with anatomic locations at imaging, with diagrams to provide a reference to aid in radiologic interpretation. ^©RSNA, 2019.

Direct In Vivo MRI Discrimination of Brain Stem Nuclei and Pathways

BACKGROUND AND PURPOSE

The brain stem is a complex configuration of small nuclei and pathways for motor, sensory, and autonomic control that are essential for life, yet internal brain stem anatomy is difficult to characterize in living subjects. We hypothesized that the 3D fast gray matter acquisition T1 inversion recovery sequence, which uses a short inversion time to suppress signal from white matter, could improve contrast resolution of brain stem pathways and nuclei with 3T MR imaging.

MATERIALS AND METHODS

After preliminary optimization for contrast resolution, the fast gray matter acquisition T1 inversion recovery sequence was performed in 10 healthy subjects (5 women; mean age, 28.8 ± 4.8 years) with the following parameters: TR/TE/TI = 3000/2.55/410 ms, flip angle = 4°, isotropic resolution = 0.8 mm, with 4 averages (acquired separately and averaged outside k-space to reduce motion; total scan time = 58 minutes). One subject returned for an additional 5-average study that was combined with a previous session to create a highest quality atlas for anatomic assignments. A 1-mm isotropic resolution, 12-minute version, proved successful in a patient with a prior infarct.

RESULTS

The fast gray matter acquisition T1 inversion recovery sequence generated excellent contrast resolution of small brain stem pathways in all 3 planes for all 10 subjects. Several nuclei could be resolved directly by image contrast alone or indirectly located due to bordering visualized structures (eg, locus coeruleus and pedunculopontine nucleus).

CONCLUSIONS

The fast gray matter acquisition T1 inversion recovery sequence has the potential to provide imaging correlates to clinical conditions that affect the brain stem, improve neurosurgical navigation, validate diffusion tractography of the brain stem, and generate a 3D atlas for automatic parcellation of specific brain stem structures.

Topographic evaluation of medullary infarcts from the radiologist's point of view

PURPOSE

Despite considerable published information about the clinical-radiological correlation of medullary infarcts, no study has determined whether topographic evaluations are performed accurately among researchers. Our purpose in this study was twofold: to evaluate the topographic pattern of medullary infarcts on diffusion-weighted imaging by their radiological aspect, and to assess interobserver agreement on the topographic pattern.

METHODS

We retrospectively reviewed our imaging and clinical database for patients admitted to our radiology department between January 2014 and September 2019. Two radiologists evaluated the imaging studies independently. Consensus data were used in the analysis.

RESULTS

The retrospective review yielded 92 patients with medullary infarction. The affected vascular territories were lateral (n = 58), anteromedial (n = 28), posterior (n = 3), and anterolateral (n = 1). Two patients had hemimedullary infarction. The rostrocaudal levels of the medullary infarct were superior (n = 34), middle (n = 31), inferior (n = 4), superior-middle (n = 13), and middle-inferior (n = 10). The medullary infarcts were divided into two types: lateral (n = 62) and medial (n = 28). The affected vascular territories differed with rostrocaudal topography of medullary infarct (p = 0.003). Excellent interobserver agreement was found for type of medullary infarct, compared with moderate for vascular territory and fair for rostrocaudal topography. The anterolateral and posterior territories were the most often misdiagnosed, while the level with the most disagreements in rostrocaudal topography was middle.

CONCLUSION

The accurate topographic evaluation of a medullary infarct can be an important basis for investigating stroke etiology. However, correct topographic evaluation may not always be available and smaller territories such as anterolateral and posterior should be assessed carefully.

Stereological analysis of the vascular network in superior colliculi

Background/Aim: Superior colliculi have an important role in the visual system, some motor functions and behaviour. Branches of the posterior cerebral artery and surrounding vessels form a collicular arterial network, which gives rise to several penetrating vessels for superior colliculi. The aim of the study was to determine relative stereological parameters (volume, surface and length density) of the vascular network in superior colliculi and to correlate those parameters with age. Methods: Ten adult brainstems, both male and female, were cut transversally at the middle of superior colliculi in three-millimetre-thick strata. Every stratum was cut in 4 µm thick semiserial sections stained with Mallory method. Images of every fifth section (5, 10, 15, 20) of superior colliculus were taken with "Leica" DM 1000 microscope and "Leica" MC 170HD camera under x 400 magnification and analysed by ImageJ software with A 100 grid. Statistical analysis was performed by the SPSS software with 5 % level of significance using methods of descriptive statistics, Spearman's and Pearson's correlation coefficient. Results: The average volume density of vascular network in superior colliculi was 0.0203 mm 0 , surface density 6.133 mm-1 , and length density 205.357 mm-2. All those parameters decreased with ageing, but statistically significant change was seen only in length density (p = 0.006). Conclusion: Compared to the structures at the same transversal level, the vascular network of superior colliculi has an average density. With ageing, blood vessels become less tortuous.

Sensorimotor ECoG Signal Features for BCI Control: A Comparison Between People With Locked-In Syndrome and Able-Bodied Controls

The sensorimotor cortex is a frequently targeted brain area for the development of Brain-Computer Interfaces (BCIs) for communication in people with severe paralysis and communication problems (locked-in syndrome; LIS). It is widely acknowledged that this area displays an increase in high-frequency band (HFB) power and a decrease in the power of the low frequency band (LFB) during movement of, for example, the hand. Upon termination of hand movement, activity in the LFB band typically shows a short increase (rebound). The ability to modulate the neural signal in the sensorimotor cortex by imagining or attempting to move is crucial for the implementation of sensorimotor BCI in people who are unable to execute movements. This may not always be self-evident, since the most common causes of LIS, amyotrophic lateral sclerosis (ALS) and brain stem stroke, are associated with significant damage to the brain, potentially affecting the generation of baseline neural activity in the sensorimotor cortex and the modulation thereof by imagined or attempted hand movement. In the Utrecht NeuroProsthesis (UNP) study, a participant with LIS caused by ALS and a participant with LIS due to brain stem stroke were implanted with a fully implantable BCI, including subdural electrocorticography (ECoG) electrodes over the sensorimotor area, with the purpose of achieving ECoG-BCI-based communication. We noted differences between these participants in the spectral power changes generated by attempted movement of the hand. To better understand the nature and origin of these differences, we compared the baseline spectral features and task-induced modulation of the neural signal of the LIS participants, with those of a group of able-bodied people with epilepsy who received a subchronic implant with ECoG electrodes for diagnostic purposes. Our data show that baseline LFB oscillatory components and changes generated in the LFB power of the sensorimotor cortex by (attempted) hand movement differ between participants, despite consistent HFB responses in this area. We conclude that the etiology of LIS may have significant effects on the LFB spectral components in the sensorimotor cortex, which is relevant for the development of communication-BCIs for this population.

Sagittal diffusion-weighted imaging in preventing the false-negative diagnosis of acute brainstem infarction: Confirmation of the benefit by anatomical characterization of false-negative lesions

Background:

In some cases of acute brainstem infarction (BI), standard axial diffusion-weighted imaging (DWI) does not show a lesion, leading to false-negative (FN) diagnoses. It is important to recognize acute BI accurately and promptly to initiate therapy as soon as possible.

Methods:

Of the 171 patients with acute cerebral infarctions in our institution who were examined, 16 were diagnosed with true-positive BI (TP-BI) and six with FN-BI. We evaluated the effectiveness of sagittal DWI in accurately diagnosing acute BI and sought to find the cause of its effectiveness by the anatomical characterization of FN-BIs.

Results:

Considering the direction of the brainstem perforating arteries, we supposed that sagittal DWI might more effectively detect BIs than axial DWI. We found that sagittal DWI detected all FN-BIs more clearly than axial DWI. The mean time between the onset of symptoms and initial DWI was significantly longer in the TP group (17.6 ± 5.5 h) than in the FN group (5.0 ± 1.2 h; P < 0.0001). The lesion volumes were much smaller in FN-BIs (259 ± 82 mm³) than in TP-BIs (2779 ± 767 mm³; P = 0.0007). FN-BIs had a significant inverse correlation with the ventrodorsal length of infarcts (FN 3.5 ± 1.1 mm, TP 11.4 ± 3.6 mm; P < 0.0004) and no correlation with other size parameters such as rostrocaudal thickness and lateral width.

Conclusion:

Anatomical characterization clearly confirmed that the addition of sagittal DWI to the initial axial DWI in suspected cases of BI ensures its accurate diagnosis and improves the patient’s prognosis.

Value of Combination of Standard Axial and Thin-Section Coronal Diffusion-weighted Imaging in Diagnosis of Acute Brainstem Infarction

AIM:

To determine the value of the combination of thin-section 3 mm coronal and standard axial DWI and their impact in facilitating the diagnosis of acute brainstem infarction.

METHODS:

A cross-sectional study conducted from the 1st of April 2017 to the end of February 2018 on 100 consecutive patients (66% were male, and 34% were female) with isolated acute ischemic infarction in the brainstem. The abnormal MRI findings concerning the ischemic lesions were interpreted on standard axial 5 mm and thin-section coronal 3mm DWI.

RESULTS:

The mean age of the studied group was 69.2 ± 4.3 for male and 72.3 ± 2.5 years. The standard axial DWI can diagnose 20%, 6.7% and 6.7% of the infarctions in midbrain, pons and medulla oblongata respectively, while both axial and thin coronal sections together can diagnose 80% of midbrain infarctions, 93.3% of pons infarctions and 93.3% of medulla oblongata infarctions. Furthermore, the thin section coronal 3 mm section can diagnose very smaller ischemic lesion volume in comparison to the standard axial 5mm section (3.4 ± 0.45 / cm³ versus 4.6 ± 0.23 / cm³, P < 0.001)

CONCLUSION:

The addition of thin-section coronal DWI can facilitate the detection of brainstem ischemic lesions. We suggest its inclusion in the stroke MRI protocol.

Imaging of Brain Infarctions: Beyond the Usual Territories

In this review, our intension is to present imaging features of several categories of uncommon cases of brain infarctions including infarctions associated with neurovascular variants, infarctions along small arterial territories, and brainstem stroke syndromes. Infarctions associated with neurovascular variants include azygos anterior cerebral artery territory infarction and artery of Percheron infarction. In the second group, we discuss anterior choroidal artery infarction and artery of Heubner infarction. The third group highlights brainstem stroke syndromes, including Claude and Benedikt syndromes due to midbrain infarction; Foville, Marie Foix, and locked-in syndromes due to pontine infarction; and Dejerine (medial medullary), bilateral medial medullary, and Wallenberg (lateral medullary) syndromes.

A cohort study of isolated brainstem infarction based on head MR imaging and clinical findings

Objective

The prognosis of patients with isolated brainstem infarction (BSI) differs on an individual patient basis. This study was undertaken to analyze the influences of different imaging and clinical features with the prognosis of patients with BSI.

Methods

The study population was derived from a multicenter study of intracranial atherosclerosis in China. In the present study, 300 patients were selected who had experienced non-cardiogenic brain stem infarction within the prior 7 days. Evaluations included clinical characteristics, location and size of the brainstem infarction, and whether the infarction was located in multiple perforating branches of the brainstem. Poor prognosis was defined as the presence of disability within 1 year from the onset of disease.

Results

In total, 281 patients were followed up at 1 year post-infarction. Of these 281 patients, 84 (29.9%) exhibited disability at 1 year; these patients showed a median National Institutes of Health Stroke Scale score of 6 on admission. Multiple logistic regression analysis showed that patients with BSI located in the territory of multiple perforating arteries, who were discharged without administration of statins, showed a poor 1-year prognosis.

Conclusion

Isolated BSI involving multiple perforating arteries, without statin medication at discharge, indicated poor prognosis for patients with BSI.

Combination of standard axial and thin-section coronal diffusion-weighted imaging facilitates the diagnosis of brainstem infarction

BACKGROUND AND PURPOSE

Although diffusion-weighted imaging (DWI) is a very sensitive technique for the detection of small ischemic lesions in the human brain, in particular in the brainstem it may fail to demonstrate acute ischemic infarction. In this study, we sought to evaluate the value of additional thin-section coronal DWI for the detection of brainstem infarction.

METHODS

In 155 consecutive patients (median age 69 [interquartile range, IQR 57-78] years, 95 [61.3%] males) with isolated brainstem infarction, MRI findings were analyzed, with emphasis on ischemic lesions on standard axial (5 mm) and thin-section coronal (3 mm) DWI.

RESULTS

On DWI, we identified ischemic lesions in the mesencephalon in 12 (7.7%), pons in 115 (74.2%), and medulla oblongata in 31 (20%) patients. In 3 (1.9%) cases-all of these with medulla oblongata infarction-the ischemic lesion was detected only on thin-section coronal DWI. Overall, in 35 (22.6%) patients the ischemic lesion was more easily identified on thin-section coronal DWI in comparison to standard axial DWI. In these, the ischemic lesions were significantly smaller (0.06 [IQR 0.05-0.11] cm³ vs. 0.25 [IQR 0.13-0.47] cm³; p < .001) in comparison to those patients whose ischemic lesion was more easily (6 [3.9%]) or at least similarly well identified (114 [73.5%]) on standard axial DWI.

CONCLUSIONS

Since thin-section coronal DWI may facilitate the diagnosis of brainstem infarction, we suggest its inclusion in standard stroke MRI protocols.