[A case of bilateral middle cerebellar peduncle infarction with hot cross bun sign].

A 71-year-old man with hypertension and diabetes mellitus presented to our hospital because he felt lightheaded. Diffusion-weighted images (DWI) on brain MRI showed high signal lesions in the left cerebellar hemisphere and the right pons. The diagnosis of cerebellar infarction was made, but he refused treatment. One month later, he came to our hospital because his body leaned to the left. Neurological examination revealed dysarthria and cerebellar truncal ataxia. An electrocardiogram showed atrial fibrillation. DWI on brain MRI showed high signal lesions in the bilateral cerebellar hemispheres and middle cerebellar peduncles (MCP). Dabigatran 300 |mg/day was administered for cardiogenic cerebral embolism. On the 12th day of onset, he was transferred to a rehabilitation hospital. At 72 years old, T2*-weighted images on brain MRI showed hot cross bun sign (HCBs) in the pons. We considered that HCBs were caused by antegrade or retrograde degeneration (or both) of pontine infarcts and bilateral MCP infarcts in the pontine cerebellar tract. It seemed preferable to use T2*-weighted images or proton density-weighted images rather than T2-weighted images to detect HCBs. When HCBs is detected, it should be noted that HCBs can be caused by bilateral MCP infarcts in addition to multiple system atrophy.

Differentiation between Parkinson's Disease and the Parkinsonian Subtype of Multiple System Atrophy Using the Magnetic Resonance T1w/T2w Ratio in the Middle Cerebellar Peduncle.

Multiple system atrophy with predominant parkinsonism (MSA-P) can hardly be distinguished from Parkinson's disease (PD) clinically in the early stages. This study investigated whether a standardized T1-weighted/T2-weighted ratio (sT1w/T2w ratio) can effectively detect degenerative changes in the middle cerebellar peduncle (MCP) associated with MSA-P and PD and evaluated its potential to distinguish between these two diseases. We included 35 patients with MSA-P, 32 patients with PD, and 17 controls. T1w and T2w scans were acquired using a 1.5-T MR system. The MCP sT1w/T2w ratio was analyzed via SPM12 using a region-of-interest approach in a normalized space. The diagnostic performance of the MCP sT1w/T2w ratio was compared between the MSA-P, PD, and controls. Patients with MSA-P had significantly lower MCP sT1w/T2w ratios than patients with PD and controls. Furthermore, MCP sT1w/T2w ratios were lower in patients with PD than in the controls. The MCP sT1w/T2w ratio showed excellent or good accuracy for differentiating MSA-P or PD from the control (area under the curve (AUC) = 0.919 and 0.814, respectively) and substantial power for differentiating MSA-P from PD (AUC = 0.724). Therefore, the MCP sT1w/T2w ratio is sensitive in detecting degenerative changes in the MCP associated with MSA-P and PD and is useful in distinguishing MSA-P from PD.

Wallerian degeneration of the ipsilateral middle cerebellar peduncle after lower pontine paramedian infarct diagnosed by magnetic resonance imaging.

We reported a case of Wallerian degeneration of the unilateral middle cerebellar peduncle (MCP) that developed after ipsilateral paramedian lower pontine infarction. The patient was a 70-year-old woman with right hemiparesis and dysarthria. Using a 3-Tesla scanner, cranial magnetic resonance imaging was performed, and an infarct was found at the left paramedian lower pons. Seven months later, an abnormal signal was found at the central portion of the left MCP, indicative of Wallerian degeneration of the pontocerebellar tract (PCT). There was no abnormality at the contralateral MCP. Usually, Wallerian degeneration of the bilateral MCPs may develop after unilateral paramedian pontine infarction, because bilateral PCTs cross each other at the midline of the basis pontis. In the present case, however, Wallerian degeneration was found at only the ipsilateral MCP. The contralateral PCT was not affected because the PCT runs in the craniocaudal direction, and our patient had a lower pontine infarct. The location of the pontine infarct (affected PCT) and the Wallerian degeneration of the side of the MCP were well correlated.

Case report: Bilateral sudden deafness in acute middle cerebellar peduncle infarction: central or peripheral?

Background: The middle cerebellar peduncle (MCP) is the most common site associated with hearing impairment in acute ischaemic stroke. Narrowing or occlusion of the vertebrobasilar artery due to atherosclerosis is thought to be the main pathogenesis of MCP infarction. Most previous reports of MCP infarction have not been clear whether the patient's hearing impairment is localized to the center or periphery. Case presentation: We report 44-year-old man with vertigo, tinnitus, and bilateral sudden sensorineural hearing loss (SSNHL) as the first symptoms. Pure Tone Audiogram revealed complete hearing loss in both ears. Acute bilateral MCP infarction was diagnosed by repeated brain magnetic resonance imaging (MRI). The brainstem auditory evoked potential (BAEP) and the electrocochleography were normal. The otoacoustic emissions showed binaural cochlear dysfunctions. After the antiplatelet, lipid-lowering, steroids and hyperbaric oxygen therapy, the pure-tone average (PTA) showed a clear improvement with 67 decibels (dB) on the right and 73 dB on the left at the 3-month follow-up. Conclusion: Vertebrobasilar diseases due to atherosclerosis should be routinely considered in middle-aged and elderly patients with vascular risk factors and bilateral hearing loss. Bilateral SSNHL can be a prodrome of acute MCP infarction and it can be peripheral. Brain MRI, brain magnetic resonance angiogram (MRA), brain and neck computed tomography angiography (CTA), BAEP, otoacoustic emissions, and Pure Tone Audiogram help to localize and qualify the diagnosis. Bilateral SSNHL localized to the periphery usually improves better and has a good prognosis. Early detection of hearing loss and intervention can help patients recover.

Middle cerebellar peduncle approach for Nocardia brainstem abscess: illustrative case.

BACKGROUND: Nocardia cyriacigeorgica represents a rare cause of cerebral abscesses. Rarer still are brainstem abscesses caused by this bacterial species in immunocompetent hosts. In fact, only one such brainstem abscess case has been described in the neurosurgical literature to our knowledge to date. Herein, a case of Nocardia cyriacigeorgica abscess in the pons is reported, as well as a description of its surgical evacuation via the transpetrosal fissure, middle cerebellar peduncle approach. The authors review the utility of this well-described approach in treating such lesions safely and effectively. Finally, the authors briefly review, compare, and contrast related cases to this one. OBSERVATIONS: Augmented reality is additive to and useful for well-described safe entry corridors to the brainstem. Despite surgical success, patients may not regain previously lost neurological function. LESSONS: The transpetrosal fissure, middle cerebellar peduncle approach is safe and effective in evacuating pontine abscesses. Augmented reality guidance supplements but does not replace thorough knowledge of operative anatomy for this complex procedure. A reasonable degree of suspicion for brainstem abscess is prudent even in immunocompetent hosts. A multidisciplinary team is critical to the successful treatment of central nervous system Nocardiosis.

Close Your Eyes and See: Stroke Sequelae versus Functional Neurological Disorder in a Physician.

The first author is a left-handed, 51-year-old nephrologist who experienced a neurologic event. She underwent neurosurgery complicated by hemorrhage. Postoperatively, she developed persistent vertigo and unilateral tongue pain which persisted for over 5 years. Early neuroimaging revealed expected encephalomalacia but no neuroanatomical basis for her symptoms. A functional neurological disorder was suspected, and she was seen by several psychiatrists and psychotherapists. However, she suspected a neuroanatomical lesion would better explain her unrelenting symptoms. After seeing many neurologists, a neuroanatomical diagnosis was finally made. The theory and practice of medicine mandate that subjective complaint guides the modality and interpretation of objective evidence. The final neurologist knew where on neuroimaging to look because she was guided by the patient's complaints - vertigo and unilateral tongue pain. In this case, detailed scrutiny of neuroimaging by a neurologist, after encephalomalacia and gliosis were fully completed, gave a more accurate neuroanatomical diagnosis and a more realistic prognosis.

Long-Term Lower Limb Motor Function Correlates with Middle Cerebellar Peduncle Structural Integrity in Sub-Acute Stroke: A ROI-Based MRI Cohort Study.

Crossed cerebellar diaschisis (CCD) has been widely investigated in patients with supratentorial stroke. However, the role of CCD in lower limb recovery after stroke is still unknown. In this study, using a region-of-interest-based analysis of diffusion tensor imaging (DTI), a total of 44 cases of stroke within 3 months onset were enrolled for assessment of the cerebral peduncle (CP) and middle cerebellar peduncles (MCP) in CCD. Compared with the control group, the fractional anisotropy ratio (rFA) and laterality index (LI) of the CP and MCP in the stroke group significantly decreased. The rFA of the MCP (unaffected side/affected side) showed a more significant correlation with 1-year paresis grading (PG), lower extremity PG, upper extremity PG, National Institutes of Health Stroke Scale (NIHSS), and functional independence measure (FIM) motor item score, in comparison to the rFA of the CP (affected side/unaffected side) (r = -0.698 vs. r = -0.541, r = -0.651 vs. r = -0.386, r = -0.642 vs. r = -0.565, r = -0.519 vs. r = -0.403, and r = 0.487 vs. r = 0.435, respectively). Furthermore, the LI of the CP had a more significant association with 1-year Brunel Balance Assessment (BBA), upper extremity PG, and Modified Rankin Scale (mRS) as compared to the LI of the MCP (r = 0.573 vs. r = 0.452; r = -0.554 vs. r = -0.528; and r = -0.494 vs. r = -0.344, respectively). We set the cutoff point for the MCP rFA at 0.925 (sensitivity: 79% and specificity: 100%) for predicting lower extremity motor function prognosis and found the receiver operating characteristic (ROC) curve of MCP rFA was larger than that of CP rFA (0.893 vs. 0.737). These results reveal that the MCP may play a significant role in the recovery of walking ability after stroke.

Microneurosurgical Anatomic Study of the Horizontal Fissure of the Cerebellum.

OBJECTIVE: The horizontal fissure of the cerebellum, which is the largest and most prominent fissure, has received less interest from anatomists and neurosurgeons. Hence, the current study aims to provide comprehensive detail about the horizontal fissure and its anatomic and surgical relationship with deeper structures such as the dentate nucleus and middle cerebellar peduncle for the benefit of the neurosurgeon. METHODS: Ten whole formalin-fixed human cadaveric cerebellar hemispheres were obtained from human cadavers donated to the institution. Different parameters of the horizontal fissure were studied, such as length, depth (medial end, lateral end, and middle), sulcal and gyral variations (superficial and deep), and its close relationship, especially at depth, with the dentate nucleus and middle cerebellar peduncle. RESULTS: The total length of the horizontal fissure on the right and the left side was 64.3 ± 7.9 mm (range, 53-77 mm) and 65.6 ± 8.01 mm (range, 53-79 mm), respectively. The medial third of the horizontal fissure, with the fewest vessels, was the most suitable place to puncture or start the dissection of the horizontal fissure. The surface projection of the center of the posterior border of the dentate nucleus lies within 20-21 mm on either side of the posterior midline along the horizontal fissure and is only approximately 4 mm deep from the horizontal fissure. CONCLUSIONS: The anatomic measurements and relationships provided in this description of the horizontal fissure will serve as a tool for surgery selection and planning, as well as an aid to improve microneurosurgical techniques, with the final goal being better patient outcomes.

Clinical features and stroke etiology in 10 patients with bilateral middle cerebellar peduncle infarctions: a preliminary study / 中华神经科杂志

Objective:To characterize clinical and neuroimaging features, etiologies, and mechanisms of bilateral middle cerebellar peduncle (MCP) infarctions.Methods:Consecutive patients with bilateral MCP infarctions treated in the Beijing Tiantan Hospital, Capital Medical University between January 1, 2020 and April 30, 2022 were enrolled in this retrospective study. The demographic data, vascular risk factors, clincial manifestations and the National Institutes of Health Stroke Scale (NIHSS) scores were collected. Brain diffusion-weighted imaging was used to assess the regions of cerebral infarction, and the extracranial and intracranial segments of the vertebrobasilar artery were evaluated using magnetic resonance angiography, or computed tomography angiography. The stroke etiology and underlying mechanism were evaluated according to the Chinese Ischemic Stroke Subclassification.Results:Ten patients with bilateral MCP infarctions (8 men and 2 women) were analyzed ultimately. The onset age were 51.0-86.0 (64.8±11.4) years. NIHSS scores were 2.0-12.0 (4.9±2.9) points at admission. All patients had vascular risk factors, most of which were hypertension (10 cases) and dyslipoproteinemia (8 cases). The most common clinical manifestations were vertigo (10 cases), followed by ataxia (9 cases) and dysarthria (8 cases). Four cases were isolated bilateral MCP infarctions, while 6 patients were combined with other vertebrobasilar artery infarctions, 4 of which were combined with cerebellar hemisphere infarctions, consistent with the clinical symptoms. The etiology in all patients was large atherosclerosis (severe stenosis or occlusion of V4 segment of vertebral artery and anterior inferior cerebellar artery; 9 cases). Five patients were classified as hypoperfusion/impaired emboli clearance, while 4 patients were considered as artery-to-artery embolism, and 1 was considered as the parent artery (plaque or thrombosis) occluding penetrating artery.Conclusions:Bilateral MCP infarctions are an extremely rare cerebrovascular disease characterized by vertigo, ataxia, and dysarthria. Cerebral infarction can be isolated or often combined with cerebellar hemisphere infarction. The etiology was mostly stenosis or occlusion of V4 segment of vertebral artery and anterior inferior cerebellar artery.

Bilateral middle cerebellar peduncle compromise due to hypoglycemic encephalopathy: A case report and literature review.

Hypoglycemic encephalopathy constitutes a critical presentation of severely diminished glucose levels. We present the case of a 53-year-old male patient with a history of diabetes mellitus with hypoglycemic encephalopathy and MRI findings of bilateral middle cerebellar peduncle lesions. Common findings of hypoglycemic encephalopathy described in the literature consist of bilateral compromise of the cerebral cortex, basal ganglia, hippocampus, and long tracts of white matter. The cerebellum and brainstem are usually not affected. This is the ninth report of cerebellar peduncle compromise with hypoglycemia. As increasing evidence regarding prognosis estimation of lesion distribution arises, we consider it important to report the different cases of rare patterns of compromise.

Role of cerebellar cortex in associative learning and memory in guinea pigs.

Time-related cognitive function refers to the capacity of the brain to store, extract, and process specific information. Previous studies demonstrated that the cerebellar cortex participates in advanced cognitive functions, but the role of the cerebellar cortex in cognitive functions is unclear. We established a behavioral model using classical eyeblink conditioning to study the role of the cerebellar cortex in associative learning and memory and the underlying mechanisms. We performed an investigation to determine whether eyeblink conditioning could be established by placing the stimulating electrode in the middle cerebellar peduncle. Behavior training was performed using a microcurrent pulse as a conditioned stimulus to stimulate the middle cerebellar peduncle and corneal blow as an unconditioned stimulus. After 10 consecutive days of training, a conditioned response was successfully achieved in the Delay, Trace-200-ms, and Trace-300-ms groups of guinea pigs, with acquisition rates of >60%, but the Trace-400-ms and control groups did not achieve a conditioned stimulus-related blink conditioned response. It could be a good model for studying the function of the cerebellum during the establishment of eyeblink conditioning.

Postoperative magnetic resonance imaging signal changes in middle cerebral peduncle after vestibular schwannoma surgery.

BACKGROUND AND PURPOSE: Preoperative compression of middle cerebellar peduncle (MCP) is often observed in vestibular schwannomas. Its re-expansion is expected after tumour resection, however, frequently its thickness remains unchanged or undergoes further atrophy. Similarly, increased MCP FLAIR signal is often observed and thought to be associated with intraoperative MCP injury. This study investigates the dynamics of MCP FLAIR signal changes over time and their implications in long-term MCP atrophy. MATERIALS AND METHODS: Retrospective analysis of patients operated between 2011 and 2019 was performed. Measurements of FLAIR signals and MCP thickness were performed preoperatively, postoperatively and at follow-up. RESULTS: 28 patients (15 females, mean age 51.94 years) were included. The mean follow-up was 23.98 months. The mean tumour size was 2.99 cm. The MCP FLAIR signal was elevated preoperatively in 10 (35.7%) patients and further increased postoperatively in 22 (78.6%), followed by its decrease at follow up (7 patients, 25%). An immediate postoperative re-expansion of middle cerebellar peduncle was observed in 24 (85.7%) patients. No association between tumour size and preoperative FLAIR was established, however tumour size was negatively associated with the MCP thickness. A significant negative association between a postoperative FLAIR and follow-up thickness (p < 0.001) was noted, even if controlling for tumour size and both tumour size and preoperative MCP thickness. CONCLUSION: In patients with vestibular schwannomas undergoing surgical resection, the middle cerebellar peduncle FLAIR signal seems to associated with long term thickness of MCP, regardless of its initial size, however does not seem to correlate with the clinical outcome.

Criteria-unfulfilled multiple system atrophy at an initial stage exhibits laterality of middle cerebellar peduncles.

To elucidate clinically useful imaging characteristics of multiple system atrophy with predominant cerebellar ataxia (MSA-C) at the initial stage showing pure cerebellar ataxia but unfilling consensus criteria (MSA-pc), clinical and neuroradiological analyses on cerebral MRI and single-photon emission computed tomography (SPECT) for measuring regional cerebral blood flow (rCBF) were performed. Seven MSA-pc patients meeting the above condition at an initial evaluation were identified, and all the MSA-pc patients later developed autonomic dysfunction and finally fulfilled the criteria for probable or possible category of MSA-C. For comparison, two patients with spinocerebellar ataxia type 6 and three patients with idiopathic cerebellar ataxia who did not exhibit autonomic dysfunction for more than three years were enrolled in this study (non-MSA-pc). As non-ataxic controls without cerebellar involvement, seven patients with Parkinson's disease were also enrolled. As a result, MRI analysis clarified a smaller pontine area and significant laterality of middle cerebellar peduncle (MCP) width in MSA-pc in comparison to non-MSA-pc and controls. SPECT analysis revealed that pontine rCBF was reduced even at the initial stage of MSA-pc. Moreover, the laterality of cerebellar rCBF values and the laterality of MCP width in MSA-pc patients exhibited a significant positive correlation, indicating anatomical and functional laterality of afferent projections to cerebellum is a characteristic finding for MSA-pc. These neuroimaging characteristics could be clinically useful to consider the possibility of the criteria-unfulfilled MSA and promote an earlier intervention after obtaining a diagnosis of probable MSA-C.

Subacute Sclerosing Panencephalitis: Restricted Diffusion and Clinical Evolution.

Background: Subacute sclerosing panencephalitis (SSPE) is a rare entity characterized by a protracted course and progressive neurological deterioration. Objective: We present patterns of diffusion restriction in eight cases of SSPE, a seldom described imaging attribute. Methods: A retrospective analysis was performed on the clinical and neuroimaging data obtained from records of patients with proven SSPE. Patients whose magnetic resonance imaging (MRI) showed evidence of diffusion restriction were included in the analysis. MRI was performed on 3 T and 1.5-T clinical MR systems. Imaging characteristics were reviewed and tabulated by two neuroradiologists. Results: Eight SSPE patients (seven men, one woman; age range: 5-15 years; mean age: 11 years) diagnosed and managed at our institute were included in the analysis. Restricted diffusion was evident in the basal ganglia (n = 3), corpus callosum (n = 2), white matter (n = 2) and in bilateral middle cerebellar peduncles (MCP) (n = 2). One patient had diffusion restriction in the genu of the corpus callosum and bilateral frontal cortical white matter. None of the diffusion-restricted lesions showed contrast enhancement or susceptibility. Six cases fulfilled the diagnostic criteria for fulminant SSPE (fSSPE). The extent of neuroparenchymal involvement was greater in this subset of patients. Conclusions: Restricted diffusion in SSPE, hitherto infrequently described, can indeed occur in both grey and white matter structures and in both supratentorial and infratentorial compartments. Parenchymal diffusion restriction in SSPE possibly reflects an early time point in the clinical evolution. A greater extent of parenchymal diffusion restriction may portend a rapid downhill course, possibly qualifying for fSSPE.

Dentate nucleus signal intensity changes on T1-weighted MRI after repeated administrations of linear and macrocyclic gadolinium-based contrast agents: a pediatric intraindividual case-control study.

BACKGROUND: An association between consecutive administrations of macrocyclic gadolinium-based contrast agent (mcGBCA) gadobutrol and linear (L)-GBCA gadopentetate dimeglumine and gadolinium retention in the pediatric brain remains incompletely understood. PURPOSE: To compare signal intensity (SI) changes in the dentate nucleus (DN) on unenhanced T1-weighted imaging (T1WI) in children who obtained mcGBCA gadobutrol with those who had previously received L-GBCA gadopentetate dimeglumine. MATERIAL AND METHODS: This retrospective study included 27 children who received L-GBCA gadopentetate dimeglumine followed by mcGBCA gadobutrol and two different control groups matched for age and sex for both periods, each involving 27 individuals with no GBCA administration from January 2010 to January 2020. DN-to-middle cerebellar peduncle (MCP) SI ratios on T1WI were determined. A repeated-measures ANOVA was performed to compare the T1WI SI ratio between children exposed to GBCA in each of the two periods and controls. Pearson correlation analysis was conducted to determine any correlation between SI ratios and confounding parameters. RESULTS: T1WI SI ratio was significantly higher in those who had only L-GBCA (1.005±0.087) or subsequent mcGBCA gadobutrol (1.002±0.104) than in control groups 1 (0.927±0.041; P<0.001) and 2 (0.930±0.041; P=0.002), respectively, but no significant difference of the T1WI SI ratio was noted between L-GBCA period and subsequent mcGBCA gadobutrol period (P=0.917). T1WI SI ratios and the L-GBCA administration number revealed a modest but significant correlation (correlation coefficient=0.034; P=0.016). CONCLUSION: Previous administration of gadopentetate dimeglumine is associated with increased T1WI SI in the DN, while subsequent administration of gadobutrol does not demonstrate any additional SI increase in the pediatric brain.

How I do it: horizontal fissure approach to the middle cerebellar peduncle.

BACKGROUND: The horizontal fissure approach is a workhorse for brainstem lesions in the central and dorsolateral pons and middle cerebellar peduncle (MCP). The cerebellopontine fissure is a V-shaped fissure with a superior and inferior limb between the cerebellum, pons, and MCP. The horizontal or petrosal fissure is at the apex of the cerebellopontine fissure and extends laterally to divide the petrosal surface of the cerebellum into superior and inferior parts. Splitting this fissure exposes the posterolateral aspect of the MCP without excessive retraction or transgression of the cerebellum. METHOD: We demonstrate and describe the horizontal fissure operative approach to the middle cerebellar peduncle for resection of a pontine cavernoma with illustrative figures and operative video. CONCLUSION: Splitting the horizontal (petrosal) fissure of the cerebellum brings the middle cerebellar peduncle into view behind the root entry zone of the trigeminal nerve, providing an expanded, safe corridor to the central and dorsolateral pons.

Characterization and diagnostic potential of diffusion tractography in multiple system atrophy.

INTRODUCTION: Microstructural integrity of the middle cerebellar peduncle (MCP) and the putamen captured by diffusion-tensor imaging (DTI) is differentially affected in the parkinsonian and cerebellar variants of multiple system atrophy (MSA-P, MSA-C) compared to Parkinson's disease (PD). The current study applied DTI and tractography in order to 1) characterize the distribution of DTI metrics along the tracts of the MCP and from the putamen in MSA variants, and 2) evaluate the usefulness of combining these measures for the differential diagnosis of MSA-P against PD in the clinical setting. METHODS: Twenty-nine MSA patients (MSA-C, n = 10; MSA-P, n = 19), with a mean disease duration of 2.8 ± 1.7 years, 19 PD patients, and 27 healthy controls (HC) were included in the study. Automatized tractography with a masking procedure was employed to isolate the MCP tracts. DTI measures along the tracts of the MCP and within the putamen were acquired and jointly used to classify MSA vs. PD, and MSA-P vs. PD. Putamen volume was additionally tested as classification feature in post hoc analyses. RESULTS: DTI measures within the MCP and putamen showed significant alterations in MSA variants compared to HC and PD. Classification accuracy for MSA vs. PD and MSA-P vs PD using diffusion measures was 91.7% and 89.5%, respectively. When replacing the putaminal DTI measure by a normalized measure of putamen volume classification accuracy improved to 95.8% and 94.7%, respectively. CONCLUSION: Multimodal information from MCP tractography and putamen volume yields excellent diagnostic accuracy to discriminate between early-to-moderately advanced patients with MSA and PD.