Magnetic Resonance Imaging Scan Of Head Research Articles

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.

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 ( >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.

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.

Study of multistep Dense U-Net-based automatic segmentation for head MRI scans.

Despite extensive efforts to obtain accurate segmentation of magnetic resonance imaging (MRI) scans of a head, it remains challenging primarily due to variations in intensity distribution, which depend on the equipment and parameters used. The goal of this study is to evaluate the effectiveness of an automatic segmentation method for head MRI scans using a multistep Dense U-Net (MDU-Net) architecture. The MDU-Net-based method comprises two steps. The first step is to segment the scalp, skull, and whole brain from head MRI scans using a convolutional neural network (CNN). In the first step, a hybrid network is used to combine 2.5D Dense U-Net and 3D Dense U-Net structure. This hybrid network acquires logits in three orthogonal planes (axial, coronal, and sagittal) using 2.5D Dense U-Nets and fuses them by averaging. The resultant fused probability map with head MRI scans then serves as the input to a 3D Dense U-Net. In this process, different ratios of active contour loss and focal loss are applied. The second step is to segment the cerebrospinal fluid (CSF), white matter, and gray matter from extracted brain MRI scans using CNNs. In the second step, the histogram of the extracted brain MRI scans is standardized and then a 2.5D Dense U-Net is used to further segment the brain's specific tissues using the focal loss. A dataset of 100 head MRI scans from an OASIS-3 dataset was used for training, internal validation, and testing, with ratios of 80%, 10%, and 10%, respectively. Using the proposed approach, we segmented the head MRI scans into five areas (scalp, skull, CSF, white matter, and gray matter) and evaluated the segmentation results using the Dice similarity coefficient (DSC) score, Hausdorff distance (HD), and the average symmetric surface distance (ASSD) as evaluation metrics. We compared these results with those obtained using the Res-U-Net, Dense U-Net, U-Net++, Swin-Unet, and H-Dense U-Net models. The MDU-Net model showed DSC values of 0.933, 0.830, 0.833, 0.953, and 0.917 in the scalp, skull, CSF, white matter, and gray matter, respectively. The corresponding HD values were 2.37, 2.89, 2.13, 1.52, and 1.53mm, respectively. The ASSD values were 0.50, 1.63, 1.28, 0.26, and 0.27mm, respectively. Comparing these results with other models revealed that the MDU-Net model demonstrated the best performance in terms of the DSC values for the scalp, CSF, white matter, and gray matter. When compared with the H-Dense U-Net model, which showed the highest performance among the other models, the MDU-Net model showed substantial improvements in the HD view, particularly in the gray matter region, with a difference of approximately 9%. In addition, in terms of the ASSD, the MDU-Net model outperformed the H-Dense U-Net model, showing an approximately 7% improvements in the white matter and approximately 9% improvements in the gray matter. Compared with existing models in terms of DSC, HD, and ASSD, the proposed MDU-Net model demonstrated the best performance on average and showed its potential to enhance the accuracy of automatic segmentation for head MRI scans.

Resonating sub-wavelength metallic wires based pads for boosting signal-to-noise ratio of birdcage head coils at 1.5T MRI

Magnetic resonance imaging (MRI) is an increasingly popular non-invasive diagnostic imaging tool in modern healthcare. The signal-to-noise ratio (SNR) of MRI can be improved by locally enhancing radiofrequency (RF) magnetic field using metamaterials — without the need for stepping up static magnetic field strength. However, designing a thin and compact metamaterial-based structure for the most commonly used 1.5T MRI systems (operating at f0∼64MHz) remains highly challenging due to long vaccum wavelength λ0∼4.7m at resonance. The limited free space available inside MRI receive coil arrays (typically 10-20mm) restricts the practical usability of any bulky resonator (with dimensions in order of meters) inside commercial 1.5T MRI head transceiver-coils. In this paper, we design a thin and compact RF metamaterial-based pad comprising dual-layer wire-array resonators that fits in the available space and provides significant magnetic field enhancement at 1.5T MRI. The metamaterial-based pad provides the SNR enhancement by a factor of ∼19, on the surface of bio-model in contact with the pad, as compared to the case without pad while maintaining specific absorption rate well below the standard safety limit. We present an equivalent circuit approach combined with a transformer-based model to compute the SNR enhancement factor of metamaterial-based pad, which adequately explains the underlying physical mechanism of metamaterial’s magnetic resonance and closely estimates our numerical findings. We believe that, when integrated into the clinical 1.5T MRI systems, our proposed metamaterial-based pad can help improve the SNR of head MRI scans, resulting in either higher image quality or reduced scan time.

Nasal Alar and Scalp Metastases From Lung Carcinoma: A Case Report and Literature Review.

Both nasal alar and scalp metastases from lung carcinoma are exceedingly rare. Herein, we report a case of an elderly male smoker who had left lung carcinoma and underwent radical resection. Seven months later, masses began to appear on his nasal alar and parietal scalp which gradually increased in size. The nasal computed tomography and head magnetic resonance imaging scan revealed a dense soft tissue shadow in the right nasal alar and nasal cavity, as well as a soft tissue nodule in the middle of the parietal scalp. A biopsy was performed and immunohistochemistry suggested poorly differentiated metastatic carcinoma that was consistent with the characteristics of primary lung carcinoma and supported the diagnosis of nasal alar and scalp metastases. Then, he received a combined treatment of Albumin paclitaxel and Xindirizumab. However, he passed away 3 months later. In addition to this case, we also review the clinical features of nose and/or scalp metastases from lung carcinoma based on previously reported cases as well as this case.

Morphometric Analysis of Age and Genderrelated Variations of Corpus Callosum by using Magnetic Resonance Imaging: A Cross-sectional Study

Introduction: The Corpus Callosum (CC) is the largest commissural bundle connecting the two cerebral hemispheres which is involved in learning, memory, thinking, three-dimensional visual ability, executive functions as well as behavioural patterns. Exact morphometric dimensions are a prerequisite before surgical interventions and stereotactic approaches to the foramen of Munro and also in cases of callosectomy for intractable epilepsy as inconsistencies exist regarding gender and age related changes of CC. Also, most published studies are from the western world and very few studies are from South-east Asia and India. Aim: To study the morphometry of CC and possible age, gender related variations using Magnetic Resonance Imaging (MRI) in the North Indian population. Materials and Methods: An observational, cross-sectional study was done in Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India from January 2019 to October 2019. A total of 200 head MRI scans, using PACS (Picture Archiving and Communication System) System Viewer software were evaluated. In all the scans, length, height, minimum and maximum thickness of CC were studied. The data were statistically analysed using STATA Software for age and gender-related differences. Student’s t-test, one-way Analysis of Variance (ANOVA), linear regression and Pearson correlation coefficient were applied. Results: The study showed decrease in thickness of body, rostrum and splenium with age, linked to generalised degeneration of cortical neurons or atrophy of white matter with advancing age. Also, there was increase in length with age, possibly due to age mediated structural dilatation in lateral ventricles. Statistically significant sexual dimorphism was observed as a larger CC length in males (74.24±4.26 mm) than females (72.67±4.16 mm) (p-value<0.001) and larger brain length in males (171.75±5.51 mm) as compared to females (163.70±5.75 mm) (p-value<0.001). Males also showed greater splenial thickness (10.15±1.79 mm) in comparison to females (9.68±1.51 mm) (p-value<0.001) which may represent the importance of distribution of fibres of visual cortex in males due to larger occipital lobe. Conclusion: The present study documented morphometry of normal CC in different gender and age groups and observed sexual dimorphism, especially greater CC length and splenial thickness in males than females. With age increase in the length and decrease in thickness of CC was seen.

Image Quality of High-Resolution 3-Dimensional Neck MRI Using CAIPIRINHA-VIBE and GRASP-VIBE: An Intraindividual Comparative Study.

Acquiring high-quality magnetic resonance imaging (MRI) of the head and neck region is often challenging due to motion and susceptibility artifacts. This study aimed to compare image quality of 2 high-resolution three-dimensional (3D) MRI sequences of the neck, controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)-volumetric interpolated breath-hold examination (VIBE), and golden-angle radial sparse parallel imaging (GRASP)-VIBE. One hundred seventy-three patients indicated for contrast-enhanced neck MRI examination were scanned using 3 T scanners and both CAIPIRINHA-VIBE and GRASP-VIBE with nearly isotropic 3D acquisitions (<1 mm in-plane resolution with analogous acquisition times). Patients' MRI scans were independently rated by 2 radiologists using a 5-grade Likert scale for overall image quality, artifact level, mucosal and lesion conspicuity, and fat suppression degree at separate anatomical regions. Interobserver agreement was calculated using the Cohen κ coefficient. The quality ratings of both sequences were compared using the Mann-Whitney U test. Nonuniformity and contrast-to-noise ratio values were measured in all subjects. Separate MRI scans were performed twice for each sequence in a phantom and healthy volunteer without contrast injection to calculate the signal-to-noise ratio (SNR). The scores of overall image quality, overall artifact level, motion artifact level, and conspicuity of the nasopharynx, oropharynx, oral cavity, hypopharynx, and larynx were all significantly higher in GRASP-VIBE than in CAIPIRINHA-VIBE (all P 's < 0.001). Moderate to substantial interobserver agreement was observed in overall image quality (GRASP-VIBE κ = 0.43; CAIPIRINHA-VIBE κ = 0.59) and motion artifact level (GRASP-VIBE κ = 0.51; CAIPIRINHA-VIBE κ = 0.65). Lesion conspicuity was significantly higher in GRASP-VIBE than in CAIPIRINHA-VIBE ( P = 0.005). The degree of fat suppression was weaker in the lower neck regions in GRASP-VIBE (3.90 ± 0.72) than in CAIPIRINHA-VIBE (4.97 ± 0.21) ( P < 0.001). The contrast-to-noise ratio at hypopharyngeal level was significantly higher in GRASP-VIBE (6.28 ± 4.77) than in CAIPIRINHA-VIBE (3.14 ± 9.95) ( P < 0.001). In the phantom study, the SNR of GRASP-VIBE was 12 times greater than that of CAIPIRINHA-VIBE. The in vivo SNR of the volunteer MRI scan was 13.6 in CAIPIRINHA-VIBE and 20.7 in GRASP-VIBE. Both sequences rendered excellent images for head and neck MRI scans. GRASP-VIBE provided better image quality, as well as mucosal and lesion conspicuities, with less motion artifacts, whereas CAIPIRINHA-VIBE provided better fat suppression in the lower neck regions.

Deep learning models for triaging hospital head MRI examinations.

The growing demand for head magnetic resonance imaging (MRI) examinations, along with a global shortage of radiologists, has led to an increase in the time taken to report head MRI scans in recent years. For many neurological conditions, this delay can result in poorer patient outcomes and inflated healthcare costs. Potentially, computer vision models could help reduce reporting times for abnormal examinations by flagging abnormalities at the time of imaging, allowing radiology departments to prioritise limited resources into reporting these scans first. To date, however, the difficulty of obtaining large, clinically-representative labelled datasets has been a bottleneck to model development. In this work, we present a deep learning framework, based on convolutional neural networks, for detecting clinically-relevant abnormalities in minimally processed, hospital-grade axial T2-weighted and axial diffusion-weighted head MRI scans. The models were trained at scale using a Transformer-based neuroradiology report classifier to generate a labelled dataset of 70,206 examinations from two large UK hospital networks, and demonstrate fast (< 5s), accurate (area under the receiver operating characteristic curve (AUC) > 0.9), and interpretable classification, with good generalisability between hospitals (ΔAUC ≤ 0.02). Through a simulation study we show that our best model would reduce the mean reporting time for abnormal examinations from 28 days to 14 days and from 9 days to 5 days at the two hospital networks, demonstrating feasibility for use in a clinical triage environment.

Artificial Intelligence Algorithm-Based Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) in the Treatment of Glioma Biopsy.

This study was aimed at exploring the application value of positron emission tomography (PET) + magnetic resonance imaging (MRI) technology based on convolutional neural network (CNN) in the biopsy and treatment of intracranial glioma. 35 patients with preoperatively suspicious gliomas were selected as the research objects. Their imaging images were processed using CNN. They were performed with the preoperative head MRI, fluorodeoxyglucose (FDG) PET, and ethylcholine (FECH) PET scans to construct the cancer tissue contours. In addition, the performance of CNN was evaluated, and the postoperative pathology of patients was analyzed. The results suggested that the CNN-based PET + MRI technology showed a recognition accuracy of 97% for images. Semiquantitative analysis was adopted to analyze the standard uptake value (SUV). It was found that the SUVFDG and SUVFECH of grade II/III glioma were 9.77 ± 4.87 and 1.82 ± 0.50, respectively, and the SUVFDG and SUVFECH of grade IV glioma were 13.91 ± 1.83 and 3.65 ± 0.34, respectively. According to FDG PET, the mean value of SUV on the lesion side of grade IV glioma was greater than that of grade II-III glioma, and the difference was significant (P < 0.05), and similar results were obtained on FECH PET. It showed that CNN-based PET + MRI fusion technology can effectively improve the recognition effect of glioma, can more accurately determine the scope of glioma lesions, and can predict the degree of malignant glioma to a certain extent.

A Rician Noise Prediction and Removal Model for MRI Head Scans using wavelet based Non-Local Median Filter

In the medical imaging field, anatomical structure preservation is a difficult task during the denoising process. Magnetic resonance imaging (MRI) scanner corrupts the images by the Rician noise during the acquisition process. Rician noise affects the diagnosis and treatment planning for the subjects. Regenerating noise-free images is a time-consuming process with limited MR scanner resources available in developing countries. Therefore, the medical industry utilizes the advancement of computer-aided automatic denoising methods. This article presents a novel denoising method for Rician noise using a wavelet-based non-local median filtering (WNLMed) technique. The work contains three phases: noise estimation, wavelet thresholding using a lifting scheme, and non-local median filter (NLMed). Materials used for this experiment are collected from the Brainweb repositories and tested with validation metrics such as normalized absolute error (NAE), peak signal to noise ratio (PSNR), structure similarity index measure (SSIM), the figure of merit (FOM), and compared with the state-of-the-art methods. The method yields high PSNR value than other methods.

Magnetic resonance imaging interactions with a sacral neuromodulation system.

AimsSacral neuromodulation (SNM) has successfully treated patients with functional urinary and/or bowel disorders for more than two decades. Historically, patients with the InterStim system (Medtronic) were contraindicated for Magnetic Resonance Imaging (MRI) scans. In 2012, Medtronic obtained Food and Drug Administration (FDA) approval for allowing 1.5 Tesla (T) MRI head scans. In September 2019, the Axonics System (Axonics) received FDA approval for 1.5 T full‐body MR Conditional labeling and then 3 T full‐body MR Conditional labeling in July 2020. In August 2020, Medtronic received 1.5 and 3 T full‐body MR Conditional labeling from the FDA for their new SNM systems (InterStim II and Micro devices with SureScanTM leads). With the advancements in MRI technology and availability of full‐body MRI eligible SNM systems, it is important for physicians to better understand MRI safety for these systems.MethodsThis paper explains the fundamentals of MRI physics, its interactions with active implantable medical devices (AIMDs), the subsequent potential safety hazards with emphasis on radio frequency (RF)‐related safety, and the risks associated with “Off‐label” scans, including abandoned and broken leads.ResultsMRI guidelines provided by the AIMD device manufacturer should be followed to ensure MRI scan safety and avoid any unnecessary risk to patients.ConclusionsMRI guidelines provided by the device manufacturer are the best resource for guidance for performing safe MRI scanning. Specific conditions should be fully understood and generalizations on MRI safety claims based on partial analysis or case studies should be avoided.

&lt;p&gt;Anaplastic Pleomorphic Xanthoastrocytoma: A Case Report and Literature Review&lt;/p&gt;

BackgroundWith an incidence of less than 1% among astrocytomas, pleomorphic xanthoastrocytoma (PXA) is rare. When its mitotic activity exceeds 5 mitoses/10 high-power fields, PXA is defined as anaplastic pleomorphic xanthoastrocytoma (APXA). This report documents the clinical manifestations and histopathological characteristics of APXA to help prevent future misdiagnoses.Case PresentationA 28-year-old male patient had a sudden limb twitch and visited a local hospital. A head magnetic resonance imaging scan showed large patches of abnormal signal intensity that were approximately 6.0×3.3 cm in size in the right frontal and parietal lobes, with iso- to slightly hypointense signals on T1-weighted images (T1WI) and mixed hyperintense signals on T2-weighted images (T2WI). Optical microscopic imaging found pleomorphic tumor cells with sheet-like growth, as well as foamy tumor cells, multinucleated giant cells, pleomorphic cells with atypical nuclei, and acidophilic bodies. Some areas were densely packed with obvious atypia and visible mitoses. The patient tested positive for glial fibrillary acidic protein (GFAP), vimentin (Vim), neuronal nuclear antigen (NeuN), P53, oligodendrocyte transcription factor-2 (OLIG-2), and ATRX, while he tested negative for synaptophysin (Syn), CD34, S-100, BRAF V600E, and IDH1 R132H. The Ki-67 labeling index was 15%. Genetic sequencing showed that IDH1 and IDH2 genes were wild-type, but that his BRAF gene harbored the V600E mutation.ConclusionAPXA is a WHO grade III astrocytoma that can be distinguished from WHO grade II PXA according to the level of mitosis. Imaging may help to inform the difficult differentiation between APXA and epithelioid glioblastoma. Nonetheless, a clear diagnosis warrants carrying out a comprehensive analysis, including histomorphological, immunophenotypic, and molecular assessments.

MRI surveillance following concurrent cochlear implantation in cases of vestibular schwannoma resection.

Cochlear nerve preserving translabyrinthine vestibular schwannoma (VS) resection enables concurrent cochlear implantation. Implantation in patients with VS raises important concerns including the ability to undergo postoperative magnetic resonance imaging (MRI) monitoring of residual tumor growth or tumor recurrence, specifically with a retained magnet. We aim to assess the feasibility of MRI monitoring and the impact on image quality with retained cochlear implant (CI) magnets. Retrospective review of post-operative head MRI scans in CI recipients with a retained CI magnet, after cochlear nerve preserving translabyrinthine excision of VS. The ability to visualize the ipsilateral and contralateral internal auditory canal (IAC) and cerebellopontine angle (CPA) were assessed. A total of eight surveillance head MRI were performed in six patients. In one case, in which the receiver was positioned lower, the view of the ipsilateral IAC and CPA was distorted. In all other cases, the views of both the ipsilateral and contralateral IAC and CPA were overall unimpaired. Imaging artifact only very rarely impedes adequate visualization of the ipsilateral IAC or CPA in CI recipients. In anticipation of the need for further IAC and CPA imaging, it would be advisable to place the receiver in an exaggerated superior-posterior position to further decrease obscuring artifact. Thus, serial monitoring of VS tumors can be performed safely with preservation of image quality with a retained receiver magnet. When placing the CI receiver-stimulator farther posterior-superiorly, excellent visualization of the IAC and CPA can be accomplished without significantly impairing the image quality.

Head and neck cancer patient images for determining auto-segmentation accuracy in T2-weighted magnetic resonance imaging through expert manual segmentations.

The use of magnetic resonance imaging (MRI) in radiotherapy treatment planning has rapidly increased due to its ability to evaluate patient's anatomy without the use of ionizing radiation and due to its high soft tissue contrast. For these reasons, MRI has become the modality of choice for longitudinal and adaptive treatment studies. Automatic segmentation could offer many benefits for these studies. In this work, we describe a T2-weighted MRI dataset of head and neck cancer patients that can be used to evaluate the accuracy of head and neck normal tissue auto-segmentation systems through comparisons to available expert manual segmentations. T2-weighted MRI images were acquired for 55 head and neck cancer patients. These scans were collected after radiotherapy computed tomography (CT) simulation scans using a thermoplastic mask to replicate patient treatment position. All scans were acquired on a single 1.5T Siemens MAGNETOM Aera MRI with two large four-channel flex phased-array coils. The scans covered the region encompassing the nasopharynx region cranially and supraclavicular lymph node region caudally, when possible, in the superior-inferior direction. Manual contours were created for the left/right submandibular gland, left/right parotids, left/right lymph node level II, and left/right lymph node level III. These contours underwent quality assurance to ensure adherence to predefined guidelines, and were corrected if edits were necessary. The T2-weighted images and RTSTRUCT files are available in DICOM format. The regions of interest are named based on AAPM's Task Group 263 nomenclature recommendations (Glnd_Submand_L, Glnd_Submand_R, LN_Neck_II_L, Parotid_L, Parotid_R, LN_Neck_II_R, LN_Neck_III_L, LN_Neck_III_R). This dataset is available on The Cancer Imaging Archive (TCIA) by the National Cancer Institute under the collection "AAPM RT-MAC Grand Challenge 2019" (https://doi.org/10.7937/tcia.2019.bcfjqfqb). This dataset provides head and neck patient MRI scans to evaluate auto-segmentation systems on T2-weighted images. Additional anatomies could be provided at a later time to enhance the existing library of contours.

Abstract TP333: The Volume of an Acute Intracerebral Hemorrhage May Be Larger Than it Appears on Computed Tomography Scan

Background and Purpose: Computed tomography (CT) scan is difficult to detect early-onset acute intracerebral hemorrhage (ICH) rich in fresh blood correctly. We identified the presence of a perihematomal low-density lesion on CT imaging, which showed a high-intensity signal on T2-weighted imaging and an iso-intensity signal on fluid-attenuated inversion recovery imaging in magnetic resonance imaging (MRI) (Figure. A~C). It located inside of the hypo-intensity rim at the edge of hematoma on gradient recalled echo T2*-weighted imaging (Figure. D). We named it the “CT wall sign” and investigated the association with imaging findings in acute ICH. Methods: Patients with acute ICH within 24 hours from onset who underwent non-contrast head CT and MRI scan at the same time periods were included. The ICH volumes on CT and MRI (cm 3 ) were measured using a three-dimensional slicer and compared. Subjects were divided according to the presence or absence of the CT wall sign and compared the neuroradiological variables. Statistical analyses were performed to evaluate the association between the CT wall sign and other imaging findings. Results: A total of 146 patients were included and the CT wall sign was observed in 42 (29%) patients. The difference in the ICH volume between MRI and CT were significantly larger in the CT wall sign-positive group than in -negative group (6.0 cm 3 versus 0.40 cm 3 , P &lt;0.001). The presence of CT wall sign was significantly associated with putamen hemorrhage ( P =0.049), large hematoma &gt; 11.36 cm 3 ( P =0.005), and niveau formation in the hematoma ( P &lt;0.001). Conclusions: The presence of the CT wall sign suggests that the volume of an acute ICH may be larger than it appears on CT imaging. Key words: Acute intracerebral hemorrhage, Computed tomography, Magnetic resonance imaging, Perihematomal low-density area.

Anatomical Point-of-Interest Detection in Head MRI Using Multipoint Feature Descriptor

Automatic detection of specific anatomical points of interest (POIs) in head magnetic resonance imaging (MRI) is a technical bottleneck in medical image registration and big data analysis for head diseases. A technique for automatically retrieving POIs in head MRI scans is explored in this study. A Haar-like feature of the image is introduced to generate the feature description vector of the POI, and the most appropriate standard vector is selected from multiple marked images. A fixed five-point joint feature description is proposed for solid POI detection, and an adaptive three-point joint feature description is proposed for cavity POI detection. A total of 516 head MRI volumes were used for anatomical point detection. A solid point detection experiment was conducted using the POIs of the right/left internal acoustic pore (RIA/LIA). The POIs of the right/left ascending segment of the internal carotid artery in the posterior cavernous sinus (RAS/LAS) were used in a cavity point detection experiment. The experimental results show that the accuracies of the solid point detection for LIA and RIA are 81.8% and 84.7%, respectively. Those of cavity point detection for LAS and RAS are 66.7% and 76.2%. The performance of the proposed method is better than those of BRIEF and SIFT algorithm. The proposed method can facilitate the marking of anatomical points for doctors, thus providing technical support for head image automatic registration and big data analysis for head diseases.

New Technologies and Applications in Sacral Neuromodulation: An Update

Recently rechargeable devices have been introduced for sacral neuromodulation (SNM) with conditional safety for full-body magnetic resonance imaging (MRI). Currently a recharge-free SNM device represents the standard implant; however, it is only approved for MRI head scans. As further new technologies with broader MRI capabilities are emerging, the advantages as well as disadvantages of both rechargeable versus recharge-free devices will be briefly discussed in this commentary from the perspective of patients, healthcare professionals, and providers.

Clinical safety of ProMRI implantable cardioverter-defibrillator systems during head and lower lumbar magnetic resonance imaging at 1.5 Tesla

Magnetic resonance imaging (MRI) has long been contraindicated in patients with implanted pacemakers, defibrillators, and cardiac resynchronisation therapy (CRT) devices due to the risk of adverse effects through electromagnetic interference. Since many recipients of these devices will have a lifetime indication for an MRI scan, the implantable systems should be developed as ‘MRI-conditional’ (be safe for the MRI environment under predefined conditions). We evaluated the clinical safety of several Biotronik ProMRI (‘MRI-conditional’) defibrillator and CRT systems during head and lower lumbar MRI scans at 1.5 Tesla. The study enrolled 194 patients at 22 sites in Australia, Canada, and Europe. At ≥9 weeks after device implantation, predefined, non-diagnostic, specific absorption rate (SAR)-intensive head and lower lumbar MRI scans (total ≈30 minutes per patient) were performed in 146 patients that fulfilled pre-procedure criteria. Three primary endpoints were evaluated: freedom from serious adverse device effects (SADEs) related to MRI and defibrillator/CRT (leading to death, hospitalisation, life-threatening condition, or potentially requiring implanted system revision or replacement), pacing threshold increase, and sensing amplitude decrease, all at the 1-month post-MRI clinical visit. No MRI-related SADE occurred. Lead values remained stable, measured in clinic and monitored daily by the manufacturer home monitoring technology.

Neurosurgical Anatomy of the Internal Carotid Artery: Magnetic Resonance Imaging Study of the Sellar Region

Transsphenoidal surgical approaches involve dissection of the posterior wall of the sphenoid sinus in close proximity to the internal carotid arteries. To reduce the risk of vascular injury, a detailed study of embalmed cadavers' sellae was conducted and found the internal carotid artery approached within 4 mm of the midline in 10% of cases, and the closest intercarotid distance (ICD) occurred in the cavernous sinus, sphenoid sinus, and supraclinoid segments in 82%, 14%, and 4% of cases, respectively. These measurements have not previously been compared with living patients with modern imaging techniques. This study measured the closest ICD of 233 coronal magnetic resonance imaging head scans from 183 patients (male= 88, female= 95) at the cavernous sinus, sphenoid sinus, or supraclinoid segments of the internal carotid artery. ICD at the sphenoid sinus was taken for all scans. The internal carotid approached within 4 mm of the midline in 1.3% of cases. The closest ICD occurred in the cavernous sinus, sphenoid sinus, and supraclinoid segments in 24.5%, 35.8%, and 39.7%, respectively. Both results were significantly different from previous cadaveric studies (chi-squared tests, P= 1.4× 10-4 and P= 6.1× 10-8, respectively). Surgically relevant measurements of the carotid arteries in the sellar are different in cadavers and living subjects. This is likely due to postmortem changes of surrounding structures. This study suggests clinically relevant anatomic studies using measurements taken from cadaveric specimens be updated with modern imaging techniques taken from living patients.