Head Magnetic Resonance Imaging Research Articles

Pearls & Oy-sters: INO Plus From Downward Herniation-A Cautionary Tale Regarding Neuro-Ophthalmologic Signatures of Brainstem Compression.

Pupillary assessment is a quintessential part of the clinical examination in neuro-intensive care patients because it provides insight into the integrity of midbrain reflex arcs. Abnormal pupils, particularly anisocoria and later bilateral fixed mydriasis, are classically used to assess expansive intracranial processes because they are frequently considered early indicators of transtentorial midbrain compression due to elevated intracranial pressure. Complex ocular motor deficits mapping to the midbrain are rarely described in the setting of high transtentorial pressure. This is likely because ocular motor deficits typically occur in conjunction with decreased consciousness and corticospinal tract dysfunction reflecting advanced midbrain compromise. We present a case of left midbrain compression due to downward herniation in a patient with acute-on-chronic bilateral subdural hematoma. Ocular motor assessment demonstrated left internuclear ophthalmoplegia (INO) and an ocular tilt reaction, termed INO plus. However, pupillary, mental status, and sensorimotor examinations were unremarkable. Head magnetic resonance imaging revealed acute perforator ischemia in the left pontomesencephalic tegmentum, localizing to the ipsilateral medial longitudinal fasciculus and graviceptive oculocephalic circuits. Microvascular compromise secondary to mechanical pressure is discussed as a causative mechanism. We caution against overreliance on "telltale pupils" in suspected brainstem compression and recommend checking for other oculomotor signs.

Paradoxical Embolism in Juveniles and Young Adults With Severe-to-Profound Sudden Sensorineural Hearing Loss.

Objective: Paradoxical embolism from right-to-left shunting is a common cause of cryptogenic stroke in the young. Circulatory ischemia of the cochlea is closely connected with severe-to-profound sudden sensorineural hearing loss. This study aimed to explore the role of paradoxical embolism in severe-to-profound sudden sensorineural hearing loss in juveniles and young adults. Methods: From August 2021 to September 2022, consecutive outpatients under 35 years of age with severe-to-profound sudden hearing loss were included in the study. Routine auditory electrophysiological testing and contrast transcranial Doppler ultrasonography (c-TCD) were conducted, and the results were retrospectively analyzed. Results: Seven patients (age: 19.4 ± 6.5 years) were enrolled, including 5 juveniles and 2 young adults. Three patients had severe deafness, and 4 patients had profound deafness. Right-to-left shunting was detected in all patients through c-TCD. Patent foramen ovale was found in 2 patients while pulmonary arteriovenous fistula was found in 1 patient through contrast transthoracic echocardiography or cardiac catheterization. No patients had precipitating factors for sudden sensorineural hearing loss, and none had abnormalities on head magnetic resonance imaging. Six patients underwent whole-exome sequencing, and no known deafness gene variant was detected. After standard treatment for 1 month, 2, 3, and 2 patients had complete, slight, and no hearing recovery, respectively. Conclusions: Paradoxical embolism is a possible cause of severe-to-profound sudden sensorineural hearing loss in juveniles and young adults. In young patients, c-TCD is an effective screening tool to detect right-to-left shunting, while contrast transthoracic echocardiography is a complementary examination to c-TCD.

Polynomial chaos expansion of SAR and temperature increase variability in 3 T MRI due to stochastic input data.

Numerical simulations are largely adopted to estimate dosimetric quantities, e.g., specific absorption rate (SAR) and temperature increase, in tissues to assess the patient exposure to the radiofrequency field generated during magnetic resonance imaging (MRI). Simulations rely on reference anatomical human models and tabulated data of electromagnetic and thermal properties of biological tissues. However, concerns may arise about the applicability of the computed results to any phenotype, introducing a significant degree of freedom in the simulation input data. In addition, simulation input data can be affected by uncertainty in relative positioning of the anatomical model with respect to the radiofrequency coil. The objective of this work is the to estimate the variability of SAR and temperature increase at 3 T head MRI due to different sources of variability in input data, with the final aim to associate a global uncertainty to the dosimetric outcomes. A stochastic approach based on arbitrary Polynomial Chaos Expansion is used to evaluate the effects of several input variabilities (anatomy, tissue properties, body position) on dosimetric outputs, referring to head imaging with a 3 T MRI scanner. It is found that head anatomy is the prevailing source of variability for the considered dosimetric quantities, rather than the variability due to tissue properties and head positioning. From knowledge of the variability of the dosimetric quantities, an uncertainty can be attributed to the results obtained using a generic anatomical head model when SAR and temperature increase values are compared with safety exposure limits. This work associates a global uncertainty to SAR and temperature increase predictions, to be considered when comparing the numerically evaluated dosimetric quantities with reference exposure limits. The adopted methodology can be extended to other exposure scenarios for MRI safety purposes.

Seasonal variability of lesions distribution in acute ischemic stroke: A retrospective study

Seasonal variability could have an impact on the incidence and outcome of stroke. However, little is known about the correlation between seasonal variability and location of acute cerebral infarction. This study aimed to explore the relationship between onset season and the lesions distribution of acute ischemic stroke (AIS). We retrospectively analysis data from 1488 AIS patients admitted to the Second Hospital of Tianjin Medical University from 2018 to 2022. All subjects completed head magnetic resonance imaging examination (MRI) and were divided into four groups according to the onset seasons. The lesions distribution of AIS was evaluated for anterior/posterior/double circulation infarction (DCI), unilateral/bilateral infarctions, and single/multiple cerebral infarctions based on MRI. Logistic regression models were employed to assess the association of season with lesions distribution of AIS. Subgroup analysis was performed in different stroke subtypes. Of 1488 patients, 387 (26.0%) AIS occurred in spring, 425 (28.6%) in summer, 331 (22.2%) in autumn and 345 (23.2%) in winter. Multivariate logistic regression demonstrated that the winter group had 2.15 times (95% CI:1.44–3.21) risk of multiple infarctions, 2.69 times (95% CI:1.80–4.02) of bilateral infarctions and 1.54 times (95% CI:1.05–2.26) of DCI compared with summer group, respectively. Subgroup analysis showed an increased risk of multiple (p < 0.01) or bilateral infarctions (p < 0.01) in small-artery occlusion (SAO) subtype, and higher risk of bilateral infarctions (p < 0.01) or DCI (p < 0.05) in large artery atherosclerosis (LAA) subtype during winter. No significant associations of season with lesions distribution in cardioembolism subtype. Our study highlighted a prominent seasonal variability in the lesions distribution of AIS, particularly in LAA and SAO subtypes. The findings could help to formulating meteorological risk warning strategies for different subtypes.

Functional connectivity alterations in the thalamus among patients with bronchial asthma.

Bronchial Asthma (BA) is a common chronic respiratory disease worldwide. Earlier research has demonstrated abnormal functional connectivity (FC) in multiple cognition-related cortices in asthma patients. The thalamus (Thal) serves as a relay center for transmitting sensory signals, yet the modifications in the thalamic FC among individuals with asthma remain uncertain. This research employed the resting-state functional connectivity (rsFC) approach to explore alterations in thalamic functional connectivity among individuals with BA. After excluding participants who did not meet the criteria, this study finally included 31 patients with BA, with a gender distribution of 16 males and 15 females. Subsequently, we recruited 31 healthy control participants (HC) matched for age, gender, and educational background. All participants underwent the Montreal Cognitive Assessment (MoCA) and the Hamilton Depression Rating Scale (HAMD) assessment. Following this, both groups underwent head magnetic resonance imaging scans, and resting-state functional magnetic resonance imaging (rs-fMRI) data was collected. Based on the AAL (Automated Anatomical Labeling) template, the bilateral thalamic regions were used as seed points (ROI) for subsequent rsFC research. Pearson correlation analysis was used to explore the relationship between thalamic functional connectivity and neuropsychological scales in both groups. After controlling for potential confounding factors such as age, gender, intelligence, and emotional level, a two-sample t-test was further used to explore differences in thalamic functional connectivity between the two groups of participants. Compared to the HC group, the BA group demonstrated heightened functional connectivity (FC) between the left thalamus and the left cerebellar posterior lobe (CPL), left postcentral gyrus (PCG), and right superior frontal gyrus (SFG). Concurrently, there was a decrease in FC with both the Lentiform Nucleus (LN) and the left corpus callosum (CC). Performing FC analysis with the right thalamus as the Region of Interest (ROI) revealed an increase in FC between the right thalamus and the right SFG as well as the left CPL. Conversely, a decrease in FC was observed between the right thalamus and the right LN as well as the left CC. In our study, we have verified the presence of aberrant FC patterns in the thalamus of BA patients. When compared to HCs, BA patients exhibit aberrant alterations in FC between the thalamus and various brain areas connected to vision, hearing, emotional regulation, cognitive control, somatic sensations, and wakefulness. This provides further confirmation of the substantial role played by the thalamus in the advancement of BA.

Artificial intelligence for volumetric measurement of cerebral white matter hyperintensities on thick-slice fluid-attenuated inversion recovery (FLAIR) magnetic resonance images from multiple centers

We aimed to develop a new artificial intelligence software that can automatically extract and measure the volume of white matter hyperintensities (WMHs) in head magnetic resonance imaging (MRI) using only thick-slice fluid-attenuated inversion recovery (FLAIR) sequences from multiple centers. We enrolled 1092 participants in Japan, comprising the thick-slice Private Dataset. Based on 207 randomly selected participants, neuroradiologists annotated WMHs using predefined guidelines. The annotated images of participants were divided into training (n = 138) and test (n = 69) datasets. The WMH segmentation model comprised a U-Net ensemble and was trained using the Private Dataset. Two other models were trained for validation using either both thin- and thick-slice MRI datasets or the thin-slice dataset alone. The voxel-wise Dice similarity coefficient (DSC) was used as the evaluation metric. The model trained using only thick-slice MRI showed a DSC of 0.820 for the test dataset, which is comparable to the accuracy of human readers. The model trained with the additional thin-slice dataset showed only a slightly improved DSC of 0.822. This automatic WMH segmentation model comprising a U-Net ensemble trained on a thick-slice FLAIR MRI dataset is a promising new method. Despite some limitations, this model may be applicable in clinical practice.

E031 Retinal vasculitis with Libman-Sacks endocarditis as presenting features of a systemic lupus erythematosus with antiphospholipid antibody syndrome patient

Abstract Background/Aims Ocular manifestations of systemic lupus erythematosus (SLE) are rarely reported at the time of disease onset. Retinal vasculitis is usually associated with the active generalised disease. We report a case of a 22-year-old lady who was diagnosed with SLE with antiphospholipid antibody syndrome (APS) as the initial presentation of retinal vasculitis and Libman-Sacs endocarditis. Methods A 22-year-old lady with a background history of benign hypermobility spectrum disorder, presented to the eye casualty with a 4-week history of right-sided visual disturbances and was diagnosed with retinal vasculitis associated with uveitis, central retinal vein occlusion with multiple emboli in the retinal artery of the right eye and a single embolus in the left eye. In terms of family history, both father and brother were diagnosed with spondyloarthropathy, and the maternal uncle had Sjogren’s syndrome. She was then referred to the medical team for proper evaluation. On query, she mentioned photosensitive rash on her face getting worse in sunlight, a history of Raynaud’s phenomenon, significant hair loss, and one miscarriage before the 10 weeks of gestation. On examination, mild alopecia and a faint butterfly rash on the face were noted. Cardiac auscultation revealed pansystolic murmur. The rest of the systemic examinations were unremarkable. Results The blood test showed thrombocytopenia (130 u/L), positive antinuclear antibody (1:80, speckled pattern) with anti-double stranded DNA (26 IU/L), low complement (C3-0.74, C4- 0.12), markedly raised anticardiolipin antibody IgG (2016 u/ml), anti beta 2 glycoprotein 1 IgG ( &amp;gt;6100 u/ml) including presence of lupus anticoagulant. Her urinary protein creatinine ratio was 66mg/mmol. 3 sets of blood cultures came back negative. Transthoracic echo showed vegetation on the posterior mitral valve leaflet (0.95x 1.2cm) with moderate mitral regurgitation while transesophageal echo additionally found the possibility of perforation at the junction of leaflets of the mitral valve which was later confirmed by cardiac magnetic resonance imaging (MRI). The head MRI scan did not show any central nervous system abnormality. She was initially treated with 500mg intravenous methylprednisolone for 3 days followed by 20mg oral prednisolone daily with gradual tapering. Hydroxychloroquine and mycophenolate mofetil were added. Her case was discussed in the cardiology multidisciplinary team meeting and an opinion from the cardiothoracic surgery was taken to consider valve replacement in the future. Due to aspirin allergy, only warfarin was considered for APS. She had 2 sessions of pan-retinal photocoagulation as well. In subsequent follow-up, it was noted significant improvements in terms of her symptoms. Conclusion Vaso-occlusive retinopathy is a rare, potentially vision-threatening initial manifestation of SLE, which can be an indicator of active disease. Early identification of patients is necessary for timely intervention and multidisciplinary team involvement is required for comprehensive treatment plans. Disclosure M. Islam: None. S. Quddus: None. M. Hughes: None. R. Kumar: None.

Practical Medical Image Generation with Provable Privacy Protection Based on Denoising Diffusion Probabilistic Models for High-Resolution Volumetric Images

Local differential privacy algorithms combined with deep generative models can enhance secure medical image sharing among researchers in the public domain without central administrators; however, these images were limited to the generation of low-resolution images, which are very insufficient for diagnosis by medical doctors. To enhance the performance of deep generative models so that they can generate high-resolution medical images, we propose a large-scale diffusion model that can, for the first time, unconditionally generate high-resolution (256×256×256) volumetric medical images (head magnetic resonance images). This diffusion model has 19 billion parameters, but to make it easy to train it, we temporally divided the model into 200 submodels, each of which has 95 million parameters. Moreover, on the basis of this new diffusion model, we propose another formulation of image anonymization with which the processed images can satisfy provable Gaussian local differential privacy and with which we can generate images semantically different from the original image but belonging to the same class. We believe that the formulation of this new diffusion model and the implementation of local differential privacy algorithms combined with the diffusion models can contribute to the secure sharing of practical images upstream of data processing.

Magnetic resonance imaging accuracy in assessing depth of invasion in tongue squamous cell carcinomas and predicting cervical nodal metastasis.

The aim of this study was to evaluate magnetic resonance imaging (MRI) accuracy in assessing the depth of invasion (DOI) compared to pathological DOI in oral tongue squamous cell carcinoma (SCC) and to determine whether MRI-measured DOI can predict lymph node metastasis in the cervical region. This retrospective study comprised 36 patients diagnosed with oral tongue SCC who underwent head and neck MRI 1-30 days before surgery and were surgically treated at King Fahad Medical City between January 2017 and November 2022. Relevant information was collected from the patients' records, and the data were analyzed to determine the radiological-histopathological correlations for the DOI and ascertain the cutoff point for nodal metastasis. A value for Pearson's correlation coefficient between MRI-measured and pathological DOI was 0.86, indicating that these measures were highly associated and consistent with each other. The MRI-measured DOI coronal view (CV) was slightly overestimated than the pathological DOI by 1.72 mm. The cutoff values for the MRI-measured DOI CV and pathological DOI that indicated nodal metastasis were 7.08 mm and 9.04 mm, respectively. Preoperative MRI is a valuable tool to accurately stage oral tongue SCC by measuring the depth of tumor invasion.

Type one chiari malformation as a cause of central sleep apnea and hypoventilation in children

ObjectivesChiari type 1 malformation (CM1) may occasionally lead to central sleep apnea (CSA). We studied, in a large clinical cohort of pediatric CM1 patients, the effect of CM1 on breathing during sleep. MethodsThis is a retrospective single pediatric pulmonology center study with a systematic evaluation of pediatric CM1 patients under age 18 with polysomnography (PSG) during 2008–2020. Children with syndromes were excluded. All patients had undergone head and spine magnetic resonance imaging. ResultsWe included 104 children with CM1 with a median age of 7 (interquartile range (IQR) 5–13) years. The median extent of tonsillar descent (TD) was 13 (IQR 10–18) mm. Syringomyelia was present in 19 children (18%). Of all children, 53 (51%) had normal PSG, 35 (34%) showed periodic breathing or central apnea and hypopnea index ≥5 h−1, and 16 (15%) displayed features of compensated central hypoventilation and end-tidal or transcutaneous carbon dioxide 99th percentile level above 50 mmHg. TD had the best predictive value for central breathing disorders. In a linear model, both age (61%) and TD (39%) predicted median breathing frequency (R = 0.33, p < 0.001). ConclusionsAlthough severe CSA is a rare complication of brainstem compression in pediatric patients with CM1, short arousal-triggered episodes of periodic breathing and mild compensated central hypoventilation are common. TD shows the best but still poor prediction of the presence of a central breathing disorder. This highlights the use of PSG in patient evaluation. Posterior fossa decompression surgery effectively treats central breathing disorders.

Metastasis infiltrating tumor to meningioma: a case report

BackgroundThere have been many reports of tumor-to-tumor metastasis, in which cancer metastasizes directly into meningiomas. However, metastasis infiltrating tumors in which cancer metastasizes around meningiomas are rare. Therefore, we report a case of metastasis originating from lung cancer that infiltrated meningioma.Case presentationA 79-year-old Japanese woman underwent head magnetic resonance imaging for brain metastasis screening before lung cancer surgery. At that time, asymptomatic meningioma of the left frontal region was accidentally found. Magnetic resonance imaging 6 months later revealed a lesion suspected to be a metastatic brain tumor close to the meningioma. Brain tumor resection was performed, and histopathological diagnosis was meningioma and metastatic brain tumor. Metastatic cancer had invaded the meningioma at the boundary between the brain tumor and metastasis.ConclusionsA sudden change in imaging findings on routine examination of meningiomas in patients with lung carcinoma may indicate a metastatic brain tumor. The form of cancer metastasis to meningioma is not limited to tumor-to-tumor metastasis, but also includes metastasis infiltrating tumors near the meningioma.

Correlation between serum ANGPTL4 levels and white matter hyperintensity and cognitive impairment in patients with cerebral small vessel disease

AbstractObjectivesTo investigate the correlation between serum angiopoietin‐like protein 4 (ANGPTL4) levels, white matter hyperintensity (WMH), and cognitive impairment (CI) in patients with cerebral small vessel disease (CSVD).MethodsThis cross‐sectional study enrolled 171 patients with CSVD who attended the First Affiliated Hospital of Xinxiang Medical University from December 2021 to July 2022. All subjects underwent a 3.0T head magnetic resonance imaging, neuropsychology assessment, and blood sampling. Serum ANGPTL4 levels were detected by enzyme‐linked immunosorbent assay and the severity of WMH was assessed by the Fazekas scale. According to the Montreal Cognitive Assessment (MoCA) scale, subjects were divided into normal cognition group (NC, n = 80) and CI group (n = 91). According to the total Fazekas scores, subjects were divided into a mild WMH group (n = 84), a moderate WMH group (n = 70), and a severe WMH group (n = 17).ResultsSerum ANGPTL4 levels were significantly higher in the CI group than in the NC group (p &lt; .05) and were negatively correlated with mini–mental state examination scores and MoCA scores (r = −0.26, −0.341, p &lt; .05). Serum ANGPTL4 levels increased significantly in the mild to moderate WMH group but tended to decrease in the severe WMH group. Binary logistic regression analysis showed that ANGPTL4 was an independent influencing factor for CSVD‐CI (OR = 2.062, 95% CI (1.591–2.674), p &lt; .001). The area under curve of ANGPTL4 for CSVD‐CI was 0.847 (0.791–0.903).ConclusionANGPTL4 may be involved in the process of white matter damage and CI in CSVD patients and shows a diagnostic value for CSVD‐CI.

Analysis of etiology and clinical features of spontaneous downbeat nystagmus: a retrospective study.

To investigate the topical diagnosis, possible etiology and mechanism of spontaneous downbeat nystagmus (sDBN) patients with dizziness/vertigo. The clinical features of dizziness/vertigo patients accompanied with DBN were retrospectively reviewed in the Vertigo Center of our hospital from January 2018 to March 2021. The clinical features of dizziness/vertigo patients accompanied with DBN were reviewed. Comprehensive VNG, bithermal caloric testing, video-head-impulse test (vHIT), vestibular-evoked myogenic potentials (VEMP), head magnetic resonance imaging (MRI), three-dimensional fluid-attenuated incersion recovery magnetic resonance imaging (3D-FLAIR MRI) in the inner ear, serum immunology and other examinations were to determine the lesion site, and analyze its possible etiology and mechanism. A total of 54 patients were included. Among them, 70.4% (n = 38) of DBN patients were diagnosed with episodic vestibular syndrome (EVS), 22.2% (n = 12) with chronic vestibular syndrome (CVS), and 7.4% (n = 4) with acute vestibular syndrome (AVS). Among all the patients, 51.9% of DBN patients had clear etiology, with central lesions of 29.6% and peripheral diseases of 22.2%. The most common diseases in DBN patients were cerebellar lesions (13.0%, n = 7) and vestibular migraine (13.0%, n = 7), followed by benign positional paroxysmal vertigo (7.4%, n = 4) and drug-related dizziness/vertigo (5.6%, n = 3). The other 48.1% of the patients had unknown etiology. 53.8% (14/26) of patients with idiopathic DBN had decreased semicircular canal function, with 42.9% (6/14) decreased posterior semicircular canal function. The posterior semicircular canal gain in DBN patients decreased compared to the anterior semicircular canal in the same conjugate plane. Patients with peripheral DBN were more prone to horizontal/torsional nystagmus during positional testing. In our study, DBN patients have a relative decrease in posterior semicircular canal gain, which is possibly a particular result found in a subset of downbeat nystagmus patients. The changes in nystagmus during positional testing may be helpful in distinguishing between peripheral and central causes.

Spontaneous recovery from post‐COVID‐19 brain fog

AbstractBackgroundOne‐third of individuals who contract novel coronavirus disease 2019 (COVID‐19) reportedly experience persistent symptoms, including respiratory issues, headache, dizziness, taste disorders, fatigue, and various psychiatric and neurological symptoms, known as post‐acute sequelae of SARS‐CoV‐2. In this case report, we present a patient who became aware of brain fog, which is cognitive impairment, approximately 2 months after their COVID‐19 symptoms had resolved, accompanied by anxiety and depression.Case PresentationThe patient, a 35‐year‐old Japanese man, was infected with COVID‐19 and resumed work approximately 2 weeks later after symptoms improved. Approximately 1 month after returning to work, the patient's concentration became impaired and he started making noticeable errors at work. These symptoms did not improve, leading him to the outpatient clinic specializing in COVID‐19 sequelae at our hospital. Here, he underwent blood tests, electroencephalography, and head magnetic resonance imaging, which did not reveal any abnormalities. Cognitive decline due to COVID‐19 sequelae was therefore suspected, prompting his evaluation in our department approximately 5 months after his initial COVID‐19 infection. Detailed cognitive function tests were performed. He was monitored without the use of medications, and his cognitive function gradually improved. Approximately 11 months after his initial COVID‐19 infection, the same cognitive function tests were conducted again, because his subjective cognitive function symptoms had disappeared, and improvement was observed in many items.ConclusionSince brain fog is a relatively common sequela, we emphasize the importance of keeping this in mind from the initial consultations and comparing results over time.

VOARiability: Interobserver and intermodality variability analysis in OAR contouring from head and neck CT and MR images.

Accurate and consistent contouring of organs-at-risk (OARs) from medical images is a key step of radiotherapy (RT) cancer treatment planning. Most contouring approaches rely on computed tomography (CT) images, but the integration of complementary magnetic resonance (MR) modality is highly recommended, especially from the perspective of OAR contouring, synthetic CT and MR image generation for MR-only RT, and MR-guided RT. Although MR has been recognized as valuable for contouring OARs in the head and neck (HaN) region, the accuracy and consistency of the resulting contours have not been yet objectively evaluated. To analyze the interobserver and intermodality variability in contouring OARs in the HaN region, performed by observers with different level of experience from CT and MR images of the samepatients. In the final cohort of 27 CT and MR images of the same patients, contours of up to 31 OARs were obtained by a radiation oncology resident (junior observer, JO) and a board-certified radiation oncologist (senior observer, SO). The resulting contours were then evaluated in terms of interobserver variability, characterized as the agreement among different observers (JO and SO) when contouring OARs in a selected modality (CT or MR), and intermodality variability, characterized as the agreement among different modalities (CT and MR) when OARs were contoured by a selected observer (JO or SO), both by the Dice coefficient (DC) and 95-percentile Hausdorff distance (HD ). The mean (±standard deviation) interobserver variability was 69.0 ± 20.2% and 5.1 ± 4.1mm, while the mean intermodality variability was 61.6 ± 19.0% and 6.1 ± 4.3mm in terms of DC and HD , respectively, across all OARs. Statistically significant differences were only found for specific OARs. The performed MR to CT image registration resulted in a mean target registration error of 1.7 ± 0.5mm, which was considered as valid for the analysis of intermodalityvariability. The contouring variability was, in general, similar for both image modalities, and experience did not considerably affect the contouring performance. However, the results indicate that an OAR is difficult to contour regardless of whether it is contoured in the CT or MR image, and that observer experience may be an important factor for OARs that are deemed difficult to contour. Several of the differences in the resulting variability can be also attributed to adherence to guidelines, especially for OARs with poor visibility or without distinctive boundaries in either CT or MR images. Although considerable contouring differences were observed for specific OARs, it can be concluded that almost all OARs can be contoured with a similar degree of variability in either the CT or MR modality, which works in favor of MR images from the perspective of MR-only and MR-guidedRT.

Association between dental restorations and artefacts on head magnetic resonance images in paediatric patients.

Magnetic resonance imaging (MRI) has become an important diagnostic tool for paediatric patients. The association between dental restorations and MRI artefacts/distortions, however, is unclear. To investigate the association between dental restorations and artefacts in head MRI in children. This retrospective analysis included patients who underwent head MRI and dental examination at Ramathibodi Hospital from January 2015 to March 2021. From dental records and dental radiographs, a dentist reviewed the amount and type of restorative materials used. Two radiologists examined the MRI scans in five sequences for the presence of distortions and quantified the magnitude and grading of any artefacts. Ninety-four patients aged 3-15 years were included. Twenty-four patients who received preformed metal crowns (PMCs) had MRI distortions. Subjects with no restorations or with tooth-coloured material or amalgam restorations or both did not exhibit distortions. The number of PMCs was related to the size of an artefact. Almost all distortions were confined to the oral cavity and maxillary sinus and did not affect the diagnostic brain area. Among the commonly used dental restorative materials for children, only PMCs were associated with artefacts on head MRI scans.

Quantitative dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer: A systematic comparison of different modelling approaches

Background and purposeDynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) describes tissue microvasculature and has prognostic and predictive potential in radiotherapy for head and neck cancer (HNC). However, lack in standardization of DCE-MRI hinders comparison of studies and clinical implementation. This study investigated the accuracy and robustness of the population arterial input function (AIF), correlations between pharmacokinetic parameters and their association to T stage and human papillomavirus (HPV) status for HNC. Materials and methodsDCE-MRI was acquired for 44 HNC patients. Population AIFs were calculated with six different approaches. DCE-MRI was analysed in primary and lymph node tumours using Tofts model (TM) with population AIFs and individual AIFs, extended TM (ETM) with individual AIFs, Brix model (BM), and areas under the curve (AUCs). Intraclass correlation, concordance correlation, Pearson correlation and Whitney Mann U test helped examining the robustness and accuracy of population AIF, correlations between DCE-MRI parameters and their association to T stage and HPV status, respectively. ResultsThe population AIF was robust but differed from individual AIFs. There was significant correlation between KtransTM/ETM and ve, TM/ETM, and KtransTM/ETM and Kep, TM/ETM. ABrix and AUCs correlated for lymph nodes. Kep, Brix correlated with ABrix, KtransTM/ETM and Kep, TM/ETM for primary tumours. Kep, TM significantly decreased with increasing T stage. Both the correlations and the parameters’ association to T stage were stronger for HPV negative lesions. ConclusionsIndividual AIF was preferred for accurate pharmacokinetic modelling of DCE-MRI. DCE-MRI parameters and their correlations were affected by the lesion type, HPV status and T staging.

Cerebral Proliferative Angiopathy as the Cause of Symptomatic Epilepsy in a Young Adult Male: A First Case Report from Indonesia

Background: Cerebral proliferative angiopathy (CPA) is a rare and distinct vascular malformation that was once considered a subset of cerebral arteriovenous malformation (AVM). Due to its relatively benign course with no distinctive clinical feature, CPA may often be overlooked and misdiagnosed with other diseases. We report a case of CPA as the underlying cause of symptomatic epilepsy. Case: A 31-year-old male presented to the outpatient clinic with a history of focal to bilateral tonic-clonic seizure for 2 years. Following conservative management with an oral antiepileptic agent, the seizure frequency significantly decreased from once daily to once or twice monthly. The patient was lost to follow-up; however, he was incidentally referred back to our clinic two years later for further evaluation. A head Magnetic Resonance Imaging and Magnetic Resonance Angiography revealed a suspicion of giant AVM in the left hemisphere. Cerebral digital subtraction angiography (DSA) was performed and revealed a CPA in the left frontal area. The patient was managed conservatively and during the 6-month follow-up period, the patient did not have any seizures. Discussion: In young adults, seizures may be caused by an underlying vascular abnormality. Cerebral DSA remained the gold standard for distinguishing various etiologies of vascular malformation, including CPA. Conservative treatment using oral antiepileptic agents was effective in controlling the seizure frequency in CPA. However, a complete diagnostic evaluation is still warranted to determine the most appropriate treatment, revealing some peculiar and unexpected etiologies in the process.

Klebsiella pneumoniae invasive syndrome with liver, lung, and brain abscesses complicated with pulmonary fungal infection: a case report and review of the literature

BackgroundKlebsiella pneumoniae invasion syndrome (KPIS) is a severe multi-site infection that is usually caused by hypervirulent Klebsiella pneumoniae. The bacteria are relatively common in Asian diabetics and can cause organ abscesses or sepsis. When patients develop intracranial infection, the prognosis is poor. After anti-infective treatment, the Klebsiella pneumoniae-induced liver and lung abscesses and pulmonary fungal infection were relieved, but the brain abscesses worsened. Such complex and severe infection cases are rarely reported. Early identification of intracranial infection, selection of antibiotics with high concentrations in cerebrospinal fluid, and active treatment of complications such as diabetes and fungal infection are of great significance for the prognosis of patients.Case presentationA 71-year-old patient diagnosed with liver abscess in another hospital was transferred to our hospital due to a worsening condition. On day 1 (day of admission), the patient was given invasive mechanical ventilation, continuous renal replacement therapy combined with endotoxin adsorption, antimicrobial treatment with imipenem-cilastatin, and percutaneous catheter drainage for liver abscess. Metagenomic next-generation sequencing in bronchoalveolar lavage fluid indicated Klebsiella pneumoniae (K. pneumoniae), Candida albicans, and Aspergillus flavus complex, and no viruses were detected. Blood and pus cultures revealed K. pneumoniae that was sensitive to piperacillin/tazobactam. The anti-infection therapy was adjusted to piperacillin/tazobactam combined with voriconazole. On day 14, a head computed tomography (CT) scan showed no significant changes, and a chest CT scan showed absorption of multiple abscesses in both lungs. The patient was still unconscious. After the endotracheal tube was removed, cranial magnetic resonance imaging (MRI) showed multiple brain abscesses. Finally, his family gave up, and the patient was discharged and died in a local hospital.ConclusionIn cases of K. pneumoniae infection, the possibility of intracranial, liver, lung, or other site infections should be considered, and physicians should be vigilant for the occurrence of KPIS. For patients suspected of developing an intracranial infection, cerebrospinal fluid should be tested and cultured as soon as possible, a head MRI should be performed, and antibiotics with high distribution in cerebrospinal fluid should be used early. When patients are complicated with diabetes, in addition to glycemic control, vigilance for concurrent fungal infections is also needed.

Brain imaging abnormalities in children with dysphagia with aspiration: A retrospective study.

Head imaging is often performed in children with persistent dysphagia with aspiration to evaluate for Chiari malformations that may be associated with dysphagia. Unfortunately, the frequency of Chiari malformations or other head imaging abnormalities in children who aspirate is unknown. The goal of this study is to determine the frequency of head imaging abnormalities in children with evidence of aspiration or penetration on video fluoroscopic swallow study (VFSS). Tertiary Children's Hospital. We performed retrospective analysis of children with a diagnosis of aspiration evaluated at our center from January 2010 through April 2021. In this study, we included children with VFSS confirmedaspiration or penetration, brain magnetic resonance imaging (MRI) performed at our center, and without known genetic, congenital craniofacial, or neurologic abnormalities. Of the 977 patients evaluated in our system during that time with a diagnosis of aspiration, 185 children met the inclusion criteria. Eight children were diagnosed with Chiari malformations (4.3%) and 94 head MRIs were abnormal (51.4%). There was no difference in VFSS findings (frequency of aspiration, penetration, penetration-aspiration score, or recommended thickness of liquid) in children with a Chiari malformation versus other abnormalities or normal brain imaging. The majority of other non-Chiari brain imaging abnormalities were nonspecific. There was no difference in VFSS findings in children with abnormal MRI findings versus normal MRI. Brain imaging abnormalities are common in children who aspirate. Intervenable lesions are rare. Further studies are required to determine patients that will most likely benefit from brain imaging.