Thoracic Magnetic Resonance Imaging Research Articles

Upfront Thoracic Magnetic Resonance Imaging for the Evaluation of Thymic Lesions to Reduce Non-Therapeutic Diagnostic Thymectomy: A Narrative Review.

Background: Thymic pathologies represent the most common lesions of the anterior mediastinum. They may be classified as malignant or benign. Current diagnostic pathways recommend an initial assessment with computed tomography (CT) imaging to delineate potentially malignant thymic lesions. Despite this, high rates of non-therapeutic thymectomy continue to be observed. This carries with it significant anaesthetic, operative, and post-operative risks, in addition to healthcare costs. Consequently, there is a growing interest in magnetic resonance imaging (MRI) as a primary diagnostic modality for lesions of the anterior mediastinum. This narrative review outlines the current approaches to the evaluation of thymic lesions, with a discussion of the strengths and limitations of CT and MRI imaging modalities. It also evaluates the current discourse on the use of upfront MRI for thymic and anterior mediastinal lesion assessment. Methods: A narrative review was performed following a search on the Medline database. Articles that were evaluated had explored the role of MRI on the evaluation of thymic and anterior mediastinal lesions. Results: Current work-up for thymic and anterior mediastinal lesions are highly variable and centre around the use of CT. Upfront MRI demonstrates a similar accuracy to CT for various thymic and anterior mediastinal pathologies; however, the efforts to integrate this approach into routine practice remain in their infancy, with no standardised guidelines that exist. Conclusions: This narrative review demonstrates that there is a paucity of evidence relating to the sensitivity and specificity of MRI compared to CT for thymic lesion analysis and their subsequent relationship with non-therapeutic thymectomy. Future prospective trials to assess the role of MRI in thymic lesion determination are required to understand whether MRI can more accurately characterise these lesions to reduce non-therapeutic thymectomy. Additionally, further research efforts are required to characterise best-practice methods for integrating MRI into diagnostic pathways for these lesions in a cost-effective and resource-conscious manner.

Potential advantage of magnetic resonance imaging in detecting thoracic wall infiltration in pleural mesothelioma: A retrospective single-center analysis

ObjectivesThoracic wall infiltration in pleural mesothelioma determines the extent of resection and can be an important prognostic factor. Currently, standardized imaging for restaging after neoadjuvant systemic therapy comprises contrast-enhanced computed tomography or positron emission tomography. Additional thoracic magnetic resonance imaging could better discriminate chest wall infiltration preoperatively and increase staging accuracy. For this reason, the added benefit of magnetic resonance imaging was evaluated at our center. MethodsA retrospective analysis of the extended imaging protocol was performed from July 2018 to March 2024, including a descriptive analysis for the patient's sex, age, tobacco consumption, asbestos exposure, histological subtype, TNM stage, Modified Response Evaluation Criteria for Solid Tumors in solid tumors, and number of neoadjuvant therapy cycles. Preoperative restaging included routine imaging and magnetic resonance imaging. After histological diagnosis of pleural mesothelioma, neoadjuvant therapy was conducted, followed by intended macroscopic complete resection, with intraoperative biopsies of suspicious chest wall lesions. Computed tomography and magnetic resonance imaging results were compared with intraoperative biopsies. ResultsTwenty-six patients (mean age, 65.50 years, 11.50% female) with operable pleural mesothelioma were included. Of the 11 patients with histologically proven chest wall infiltration, 10 (90.91%) had a cT-stage 3 or greater and 4 (36.36%) underwent surgery that resulted in an R2 resection. Thoracic magnetic resonance imaging showed a high sensitivity (90.91%) for the detection of chest wall infiltration, especially when compared with the computed tomography scan (9.09%). ConclusionsWith the adjunctive use of magnetic resonance imaging, we demonstrated a higher sensitivity for detection of chest wall infiltration compared with conventional imaging before surgery. This may improve patient selection for surgery. Nevertheless, larger studies are required to confirm these results.

The need for thoracic magnetic resonance imaging before vertebral augmentation surgery in patients with lumbar vertebral fractures

BackgroundOsteoporotic vertebral compression fractures (OVCFs) of the lumbar region may be accompanied by thoracic fractures. Treating only the lumbar fractures can lead to worsening of the thoracic fractures or unresolved...

Multi-modal evaluation of respiratory diaphragm motion in chronic obstructive pulmonary disease using MRI series and CT images.

Chronic obstructive pulmonary disease (COPD), characterized by airflow limitation and breathing difficulty, is usually caused by prolonged inhalation of toxic substances or long-term smoking habits. Some abnormal features of COPD can be observed using medical imaging methods, such as magnetic resonance imaging (MRI) and computed tomography (CT). This study aimed to conduct a multi-modal analysis of COPD, focusing on assessing respiratory diaphragm motion using MRI series in conjunction with low attenuation volume (LAV) data derived from CT images. This study utilized MRI series from 10 normal subjects and 24 COPD patients, along with thoracic CT images from the same patients. Diaphragm profiles in the sagittal thoracic MRI series were extracted using field segmentation, and diaphragm motion trajectories were generated from estimated diaphragm displacements via registration. Re-sliced sagittal CT images were used to calculate regional LAVs for four distinct lung regions. The similarities among diaphragm motion trajectories at various positions were assessed, and their correlations with regional LAVs were analyzed. Compared with the normal subjects, patients with COPD typically exhibited fewer similarities in diaphragm motion, as indicated by the mean normalized correlation coefficient of the vertical motion component (0.96 for normal subjects vs. 0.76 for severity COPD patients). This reduction was significantly correlated with the LAV% in the two lower lung regions with a regression coefficient of 0.81. Our proposed evaluation method may assist in the diagnosis and therapy planning for patients with COPD.

Potential Advantage of Magnetic Resonance Imaging in Detecting Thoracic Wall Infiltration in Pleural Mesothelioma. A Retrospective Single Center Analysis.

Abstract Background Thoracic wall infiltration in pleural mesothelioma (PM) can be an important prognostic factor when determining the extent of resection. Currently, standardized imaging for restaging after neoadjuvant systemic therapy comprises contrast enhanced Computed Tomography (CT) or Positron Emission Tomography (PET/CT) scan. Aims However, thoracic Magnetic Resonance Imaging (MRI) could be a better discriminator of chest wall infiltration prior to surgery. To increase the preoperative staging accuracy, we introduced a MRI protocol at our center. Methods A retrospective analysis of this prospective new imaging protocol was performed from 07/2018 to 08/2023, including descriptive analysis for patient`s sex, age, nicotine consumption, asbestos exposure, histological subtype, TNM-stage, RECIST criteria and number of neoadjuvant therapy cycles. Preoperative restaging included routine imaging and MRI. After histological diagnosis of PM, neoadjuvant therapy was conducted, followed by partial pleurectomy or extended pleurectomy/decortication, with intraoperative biopsies of suspicious chest wall lesions. The CT/MRI results were compared to the intraoperative biopsies. Sensitivity and specificity of both modalities were analyzed. Results Twenty-five patients (mean age 65.4, 12% female) with possible chest wall infiltration were included out of the 35 patients with PM treated during the observation period. Of the 10 patients with actual chest wall infiltration, 9 (90%) had a T-Stage of 3 or higher, 9 (90%) had PM of epithelioid histologic subtype and 4 (40%) a R2-Resection. The mean overall survival of all patients was 18.88 months (8-58). In our study, thoracic MRI showed a high sensitivity (90%) and specificity (100%) for the detection of chest wall infiltration, especially when compared to the CT scan (sensitivity of 10%). Conclusion With the adjunctive use of thoracic MRI we demonstrated a higher sensitivity for detection of chest wall infiltration compared to conventional imaging prior to surgery. This may facilitate the preoperative assessment of the extent of resection. Nevertheless, larger studies are required to confirm these results.

Ectopic epipericardial fat necrosis: a case report

BackgroundEpipericardial fat necrosis (EFN) is a rare disease in which local inflammation and necrosis occur in the adipose tissue surrounding the heart, particularly epicardial fat. Few cases of EFN in which surgical resection was performed have been reported. We report a case of EFN after surgical resection of a right extrapulmonary tumor, in which a malignant disease could not be excluded.Case presentationA 75-year-old male patient presented with fever and chest pain. A contrast-enhanced computed tomography scan of the chest revealed a lesion, 53 × 48 mm in size, with mixed fatty density spanning the middle and lower lobes of the right lung. Thoracic magnetic resonance imaging (MRI) revealed a mass with mixed fat and soft tissue density in the same area; the lesion was contiguous with pericardial fatty tissue. The tumor was diagnosed as a liposarcoma or teratocarcinoma based on imaging results; however, the possibility of lung cancer could not be excluded. Finally, EFN was diagnosed based on the postoperative histopathological examination. The patient underwent surgical resection of the suspected right extrapulmonary tumor. The intraoperative findings revealed a mediastinal mass contiguous with pericardial fat located between the middle and lower lobes. Intraoperative pathological examination of the lesion was performed using a needle biopsy; however, no definitive diagnosis was made. The tumor may have invaded the middle lobe of the right lung, and partial resection of the right lower lobe was performed in addition to resection of the middle lobe of the right lung. The patient was followed up every 3 months without adjuvant therapy. No recurrence was reported at 1 year after surgery.ConclusionEFN should be considered in the differential diagnosis of an extrapulmonary tumor when continuity with the pericardial space is observed on MRI or other imaging studies. Surgical resection is useful in the diagnosis and treatment of EFNs. Preoperative three-dimensional reconstructive imaging and MRI should be used to identify vascular structures and confirm the continuity of the lesion with the surrounding tissues to ensure safe and rapid tumor removal.

Clinical and imaging findings in dogs with nerve root signature associated with cervical intervertebral disc herniation.

Intervertebral disc herniation (IVDH) is the most common spinal cord disease in dogs. Little information is available regarding the clinical presentation of nerve root signature (NRS) associated with cervical IVDH. To detail the clinical and magnetic resonance imaging (MRI) findings in dogs with NRS associated with cervical IVDH. Forty-seven client-owned dogs presenting with thoracic limb NRS and MRI confirmed IVDH. Medical records from 2010 to 2020 were retrospectively reviewed for dogs that met inclusion criteria. Imaging studies were evaluated by 2 individuals to characterize location and severity of neural tissue compression. Chondrodystrophoid dogs comprised the majority of the study cohort, with dachshund the most common breed (n = 10). Three-quarters of dogs were ≥7 years of age. Interobserver agreement was moderate or good for all of the imaging variables evaluated. The C6-C7 intervertebral disc space was significantly overrepresented (P = .01), comprising 32% (15/47) of the affected discs. However, 42% (20/47) of cases involved C2-C3 though C4-C5 disc sites. Disc material was more frequently located laterally compared to medially within the vertebral canal (P = .0005), and to be associated with compression of the nerve root at the level of the intervertebral foramen (P = .012). NRS is most commonly associated with lateralized or foraminal cervical disc herniations. It is most prevalent with C6-C7 intervertebral disc involvement, suggesting that there might be unique anatomic factors that contribute to development of NRS at this site, but can be a clinical manifestation of IVDH occurring anywhere along the cervical spine.

Attention-Aware Non-Rigid Image Registration for Accelerated MR Imaging.

Accurate motion estimation at high acceleration factors enables rapid motion-compensated reconstruction in Magnetic Resonance Imaging (MRI) without compromising the diagnostic image quality. In this work, we introduce an attention-aware deep learning-based framework that can perform non-rigid pairwise registration for fully sampled and accelerated MRI. We extract local visual representations to build similarity maps between the registered image pairs at multiple resolution levels and additionally leverage long-range contextual information using a transformer-based module to alleviate ambiguities in the presence of artifacts caused by undersampling. We combine local and global dependencies to perform simultaneous coarse and fine motion estimation. The proposed method was evaluated on in-house acquired fully sampled and accelerated data of 101 patients and 62 healthy subjects undergoing cardiac and thoracic MRI. The impact of motion estimation accuracy on the downstream task of motion-compensated reconstruction was analyzed. We demonstrate that our model derives reliable and consistent motion fields across different sampling trajectories (Cartesian and radial) and acceleration factors of up to 16x for cardiac motion and 30x for respiratory motion and achieves superior image quality in motion-compensated reconstruction qualitatively and quantitatively compared to conventional and recent deep learning-based approaches. The code is publicly available at https://github.com/lab-midas/GMARAFT.

Idiopathic Ventral Spinal Cord Herniation: An Illustrative Case and Literature Review

Background and Importance: Idiopathic spinal cord herniation (ISCH), or spontaneous spinal cord herniation, is a rare but serious condition that can cause progressive myelopathy and irreversible neurological deficits if left untreated. The condition is marked by the gradual herniation of the spinal cord through a ventral defect in the dura, leading to compromised blood flow and neurological deficits. Common symptoms include Brown-Séquard syndrome or asymmetrical paraparesis. Treatment options typically focus on reducing the strangulated spinal cord and closing the dural defect with a synthetic patch. Case Presentation: We present the case of an adult woman with progressive asymmetrical weakness of the lower limbs compatible with spastic paraparesis. Thoracic magnetic resonance imaging (MRI) revealed characteristic features of ISCH at the T3-T4 level. Intraoperative neurophysiological monitoring was used during the surgical intervention, which involved a 3-level laminectomy, dura opening, excision of the dentate ligament, and reduction of the cord across the dural defect. The defect was then filled with an autogenous piece of muscle, followed by the closure of the defect with an artificial dural patch and dural closure. At the 6-month follow-up, the patient showed favorable improvement. Conclusion: Patients with slowly progressive paraparesis or Brown-Séquard syndrome should consider the possibility of ISCH as a potential cause, despite its rarity. In symptomatic cases, the preferred treatment option often involves reducing the incarcerated spinal cord followed by covering the dural defect.

Artificial Intelligence to Preoperatively Predict Proximal Junction Kyphosis Following Adult Spinal Deformity Surgery: Soft Tissue Imaging May Be Necessary for Accurate Models.

Retrospective cohort. In a cohort of patients undergoing adult spinal deformity (ASD) surgery, we used artificial intelligence to compare three models of preoperatively predicting radiographic proximal junction kyphosis (PJK) using: (1) traditional demographics and radiographic measurements, (2) raw preoperative scoliosis radiographs, and (3) raw preoperative thoracic magnetic resonance imaging (MRI). Despite many proposed risk factors, PJK following ASD surgery remains difficult to predict. A single-institution, retrospective cohort study was undertaken for patients undergoing ASD surgery from 2009 to 2021. PJK was defined as a sagittal Cobb angle of upper-instrumented vertebra (UIV) and UIV+2>10° and a postoperative change in UIV/UIV+2>10°. For model 1, a support vector machine was used to predict PJK within 2 years postoperatively using clinical and traditional sagittal/coronal radiographic variables and intended levels of instrumentation. Next, for model 2, a convolutional neural network (CNN) was trained on raw preoperative lateral and posterior-anterior scoliosis radiographs. Finally, for model 3, a CNN was trained on raw preoperative thoracic T1 MRIs. A total of 191 patients underwent ASD surgery with at least 2-year follow-up and 89 (46.6%) developed radiographic PJK within 2 years. Model 1: Using clinical variables and traditional radiographic measurements, the model achieved a sensitivity: 57.2% and a specificity: 56.3%. Model 2: a CNN with raw scoliosis x-rays predicted PJK with a sensitivity: 68.2% and specificity: 58.3%. Model 3: a CNN with raw thoracic MRIs predicted PJK with average sensitivity: 73.1% and specificity: 79.5%. Finally, an attention map outlined the imaging features used by model 3 elucidated that soft tissue features predominated all true positive PJK predictions. The use of raw MRIs in an artificial intelligence model improved the accuracy of PJK prediction compared with raw scoliosis radiographs and traditional clinical/radiographic measurements. The improved predictive accuracy using MRI may indicate that PJK is best predicted by soft tissue degeneration and muscle atrophy.

Predictors of Skip Laminotomy for Placement of Paddle Leads for Spinal Cord Stimulation

ObjectivesPlacement of a standard paddle lead for spinal cord stimulation (SCS) requires a laminotomy for positioning of the lead within the epidural space. During initial placement, an additional laminotomy or laminectomy, termed a “skip” laminotomy, may be necessary at a higher level to pass the lead to the appropriate midline position. Patient and radiographic factors that predict the need for a skip laminotomy have yet to be identified. Materials and MethodsParticipants who underwent SCS paddle placement at Albany Medical Center between 2016 and 2017 were identified. Operative reports were reviewed to identify the paddle type, level of initial laminotomy, target level, and skip laminotomy level. Preoperative thoracic magnetic resonance images (MRIs) were reviewed, and spinal canal diameter, interpedicular distance, and dorsal cerebral spinal fluid thickness were measured for each participant when available. ResultsA total of 106 participants underwent thoracic SCS placement. Of these, 97 had thoracic MRIs available for review. Thirty-eight participants required a skip laminotomy for placement of the paddle compared with 68 participants who did not. There was no significant difference in demographic features including age, sex, body mass index, and surgical history. Univariate analyses that suggested trends were selected for further analysis using binary logistic regression. Level of initial laminotomy (odds ratio [OR] = 1.51, p = 0.028), spinal canal diameter (OR = 0.71, p = 0.015), and dorsal cerebrospinal fluid thickness (OR = 0.61, p = 0.011) were correlated with skip laminotomy. Target level (OR = 1.27, p = 0.138) and time from trial (1.01, p = 0.117) suggested potential association. The multivariate regression was statistically significant, X2(10) = 28.02, p = 0.002. The model explained 38.3% of the variance (Nagelkerke R2) and predicted skip laminectomy correctly in 73.3% of cases. However, for the multivariate regression, only a decrease in spinal canal diameter (OR = 0.59, p = 0.041) was associated with a greater odds of skip laminotomy. ConclusionsThis study aims to characterize the patient and radiographic factors that may predict the need to perform a skip laminotomy during the initial placement of SCS paddles. Here, we show that radiographic and anatomic variables, primarily spinal canal diameter, play an important role in predicting the need for a skip laminotomy. Furthermore, we suggest that target level for placement and level of initial laminotomy also may contribute. Further investigation of the predictive factors for performing a skip laminotomy would help optimize surgical planning and preoperative patient selection and counseling.

Deep learning based automatic segmentation of organs-at-risk for 0.35 T MRgRT of lung tumors

Background and purposeMagnetic resonance imaging guided radiotherapy (MRgRT) offers treatment plan adaptation to the anatomy of the day. In the current MRgRT workflow, this requires the time consuming and repetitive task of manual delineation of organs-at-risk (OARs), which is also prone to inter- and intra-observer variability. Therefore, deep learning autosegmentation (DLAS) is becoming increasingly attractive. No investigation of its application to OARs in thoracic magnetic resonance images (MRIs) from MRgRT has been done so far. This study aimed to fill this gap.Materials and methods122 planning MRIs from patients treated at a 0.35 T MR-Linac were retrospectively collected. Using an 80/19/23 (training/validation/test) split, individual 3D U-Nets for segmentation of the left lung, right lung, heart, aorta, spinal canal and esophagus were trained. These were compared to the clinically used contours based on Dice similarity coefficient (DSC) and Hausdorff distance (HD). They were also graded on their clinical usability by a radiation oncologist.ResultsMedian DSC was 0.96, 0.96, 0.94, 0.90, 0.88 and 0.78 for left lung, right lung, heart, aorta, spinal canal and esophagus, respectively. Median 95th percentile values of the HD were 3.9, 5.3, 5.8, 3.0, 2.6 and 3.5 mm, respectively. The physician preferred the network generated contours over the clinical contours, deeming 85 out of 129 to not require any correction, 25 immediately usable for treatment planning, 15 requiring minor and 4 requiring major corrections.ConclusionsWe trained 3D U-Nets on clinical MRI planning data which produced accurate delineations in the thoracic region. DLAS contours were preferred over the clinical contours.

Open surgical ligation of a thoracic spinal epidural arteriovenous fistula causing thoracic myelopathy: illustrative case.

Spinal epidural arteriovenous fistulas (eAVFs) are rare spinal vascular malformations characterized by an abnormal connection from the paraspinal and paravertebral system to the epidural venous plexus. This contrasts with the more frequently seen spinal dural AVF, where the fistula is entirely intradural. Although endovascular repair is commonly performed for spinal eAVF, few cases require open surgical ligation. The authors present a case of a 74-year-old male with progressive thoracic myelopathy secondary to a spinal eAVF. Thoracic magnetic resonance imaging (MRI) showed intramedullary T2 signal hyperintensity from T8 to T12. Spinal angiography revealed a primary arterial supply from the right T11 segmental artery and minor supply from the left T11 branches with drainage into the ventral epidural space. The patient underwent T11-12 laminectomy and complete right T11-12 facetectomy for ligation of the fistula with T11-L1 fusion. A postoperative spinal angiogram showed resolution of the fistula. Postoperatively, the patient's myelopathy improved, and MRI showed a decrease in T2 cord intensity. Spinal eAVFs are rare lesions that differ from the more commonly seen intradural dural AVF in that the abnormal connection is in the epidural space, and they are often associated with a dilated epidural venous pouch. Treatment involves endovascular, open surgical, or combined approaches.

Hematomyelia associated with coronavirus disease 2019: A rare case report.

Coronavirus disease 2019 (COVID-19) can damage the central nervous system. Although there have been reports of cerebral hemorrhage and infarction caused by COVID-19, hematomyelia due to COVID-19 has never been reported. A 40-year-old male was admitted to the hospital with positive nucleic acid detection for COVID-19 after experiencing fever for 2 weeks, urinary retention, fecal retention, and pain in both lower extremities for a week. The patient diagnosis was established using thoracic and lumbar magnetic resonance imaging (MRI). Contrast-enhanced thoracic and lumbar MRI revealed subdural (dorsal predominant) short T1 and slightly long T2 bands in the T12-S2 infundibular canal in the scan field, and the subdural hematoma was yet to be distinguished from other diseases. Spinal cord edema was observed in the left vertebral plate and facet joint of the T11 vertebral body, indicative of inflammation. The cerebrospinal fluid (CSF) was positive for COVID-19 nucleic acid. Antiinfection, immunomodulation, correction of acid-base balance and electrolyte disorders, improvement of circulation, nerve nutrition, and other symptomatic supportive treatments were administered to the patient. The patient symptoms significantly improved after 4 weeks of anti-infection and immunomodulatory therapy. Repeat thoracolumbar MRI revealed absorption of the spinal cord hematoma, and the patient was discharged from the hospital. To date, COVID-19-related hematomyelia has not been reported and anti-infective and immunomodulatory therapies may be effective. COVID-19 not only easily leads to brain injury but can also cause spinal cord injury and even spinal cord hemorrhage. When patients with COVID-19 experience symptoms and signs of spinal cord injury, spinal cord injury and bleeding caused by COVID-19 should be considered, and MRI and lumbar puncture should be performed as soon as possible to make a clear diagnosis.

Do Cervical Parameters Increase the Risk of Thoracic Spinal Stenosis in Patients with Cervical Spinal Stenosis?

The diagnosis and treatment of tandem stenosis have been widely discussed. However, studies on concurrent cervical and thoracic spinal stenosis are rare in the literature. This study was aimed to investigate the risk factors for thoracic spinal stenosis (TSS) in patients with cervical spinal stenosis (CSS). This retrospective cohort study assessed the risk factors for TSS in 162 patients who were diagnosed with CSS. Patients were divided into TSS (n=45) and non-TSS (n=117) groups. We retrospectively analyzed clinical characteristics and radiographic parameters, including age, gender, body mass index, ossification of the cervical posterior longitudinal ligament (OPLLc), hypertrophy of cervical ligamentum flavum (HLFc), cervical stenosis segments, and cervical sagittal parameters. Cervical sagittal parameters were measured on T2-weighted magnetic resonance imaging (MRI), including C2-7 Cobb angle (Cobb), cervical tilt (CT), T1 slope (T1S), thoracic inlet angle (TIA), C2-C7 sagittal vertical axis (C2-C7 SVA) and cervical curvature. Two groups showed significant differences in OPLLc, HLFc, cervical stenosis segments, and TIA. The receiver operating characteristic curves (ROC) demonstrated that the optimal threshold for TIA was 68.25. In multivariate logistic regression analysis, OPLLc (OR=4.403,95% CI=1.782-10.880,P=0.001), HLFc (OR=4.849,95% CI=1.995-11.782,P<0.001) and TIA>68.25 ° (OR=2.555,95%CI=1.044-6.251,p=0.040) were independent risk factors for TSS. Moreover, the multi-index ROC curve demonstrated that the area under the curve for predicted probability was 0.799 (p<0.001). Routine thoracic MRI assessment is strongly recommended in CSS patients with OPLLc, HLFc, and enlarged TIA to screen for neglected but vital thoracic disease.

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage.

Transvenous implantable cardioverter-defibrillator (ICD) shocks have been associated with cardiac biomarker elevations and are thought in some cases to contribute to adverse clinical outcomes and mortality, possibly from myocardium exposed to excessive shock voltage gradients. Currently, there are only limited data for comparison with subcutaneous ICDs. We sought to compare ventricular myocardium voltage gradients resulting from transvenous (TV) and subcutaneous defibrillator (S-ICD) shocks to assess their risk of myocardial damage. A finite element model was derived from thoracic magnetic resonance imaging (MRI). Voltage gradients were modeled for an S-ICD with a left-sided parasternal coil and a left-sided TV-ICD with a mid-cavity, a septal right ventricle (RV) coil, or a dual coil lead (TV mid, TV septal, TV septal + superior vena cava [SVC]). High gradients were defined as > 100 V/cm. The volumes of ventricular myocardium with high gradients > 100 V/cm were 0.02, 2.4, 7.7, and 0 cc for TV mid, TV septal, TV septal + SVC, and S-ICD, respectively. Our models suggest that S-ICD shocks produce more uniform gradients in the myocardium, with less exposure to potentially damaging electrical fields, compared to TV-ICDs. Dual coil TV leads yield higher gradients, as does closer proximity of the shock coil to the myocardium.

Posterior Spinal Cord Infarct: To Make the Diagnosis, Think of the Unthinkable! (P12-5.004)

<h3>Objective:</h3> We report a case of posterior spinal artery (PSA) infarct initially misdiagnosed as transverse myelitis (TM) and highlight some of the differentiating features of this exceedingly rare entity. <h3>Background:</h3> Spinal cord infarcts (SCIs) represent 1% of strokes and 5–8% of acute myelopathy. In a systematic review of 133 cases of SCI collected over two decades, PSAs presented 11% of the total pool. Redundancy in the vascular supply of the posterior portion of the spinal cord accounts for PSA rarity. <h3>Design/Methods:</h3> A single case report. <h3>Results:</h3> A 62-year-old woman with a history of recurrent nephrolithiasis, vitamin B12 deficiency, hypertension, and hyperlipidemia presented painless and rapidly progressive severe numbness and weakness of the legs. Sphincter symptoms were absent. Enhanced Magnetic Resonance Imaging (MRI) of the brain and spinal cord were unremarkable. Cerebral spinal fluid (CSF) was unremarkable. She was diagnosed with TM, given a five-day course of intravenous (IV) steroids, and discharged to a rehabilitation facility with a protracted and incomplete recovery. She presented two years later with fluctuating sensory and motor symptoms in the context of ureteral stent removal. Repeat CSF was unremarkable. However, on repeat thoracic spine MRI, there was interval development of a T2 hyperintensity along the dorsal columns and myelomalacia from T3–T4 disc to T12. She received IV steroids with minimal improvement. She had recurrent myelopathy pseudoexacerbations in the context of concurrent illnesses subsequently. Spinal magnetic resonance angiography, computerized chest, abdomen, pelvis tomography, positron emission tomography scan, and cardiovascular investigations were unremarkable. <h3>Conclusions:</h3> Given its scarcity, PSA infarct can often go misdiagnosed. A high index of suspicion for PSA should be kept in mind, particularly in the case of 1) acute, severe, and rapidly progressive myelopathic symptoms, 2) an extensively normal CSF analysis, and 3) an initially normal MRI of the spinal cord that eventually shows some T2 hyperintensity and cord atrophy. <b>Disclosure:</b> Dr. Solis has nothing to disclose. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Celgene/BMS. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genzyme. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Merck Serono. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva Neurosciences. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving as a Consultant for TG Therapeutics. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Teva. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Novartis. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Genentech. Dr. Zabad has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for BMS. The institution of Dr. Zabad has received research support from Adamas. The institution of Dr. Zabad has received research support from Biogen. The institution of Dr. Zabad has received research support from Novartis. The institution of Dr. Zabad has received research support from Sun Pharma. The institution of Dr. Zabad has received research support from Parexel &amp; MedDay Pharmaceuticals.

Schmorl's nodes are associated with prevalent osteoporotic vertebral fracture and low bone mineral density: a population-based thoracic spine MRI study in older men and women.

Schmorl's node (SN) corresponds to nucleus pulposus herniation into the vertebral spongy bone with thickened trabeculae around the formed node. We hypothesize that a pathway may exist that: osteoporosis → weakened endplate → SN development ↔ endplate fracture of an osteoporotic vertebra. For osteoporotic fractures in men (MrOS) and in women (MsOS) Hong Kong studies, at 14-year follow-up, thoracic spine magnetic resonance imaging (MRI) was sampled in 270 males (mean: 82.9±3.7 years) and 150 females (mean: 81.5±4.3 years). SN and Modic change were assessed as existed or not existed. For posterior disc protrusion, ligamentum flavum ossification, and spinal canal stenosis, semi-quantitative gradings were applied. For each vertebra in women, a score of 0, 0.5, 1, 1.5, 2, 2.5, 3 was assigned for no osteoporotic vertebral fracture (OVF) or OVF of <1/5, ≥1/5-1/4, ≥1/4-1/3, ≥1/3-2/5, ≥2/5-2/3, and ≥2/3 vertebral height loss, respectively, and a summed score was calculated by summing up the scores of vertebrae T1 to T12. For men, those of minimal grade were not considered as OVF and assigned a '0' score. SN prevalence in women (55.5%) almost doubled that in men (25.9%). SN was statistically significantly correlated with lower bone mineral density (BMD) derived femoral neck T-score, while the other four spine degeneration changes were not statistically significantly correlated with the T-score. SN were statistically significantly correlated with OVF score. Subjects with SN were more likely to have OVF, with odds ratio for men of 4.32 [95% confidence interval (CI): 1.70-11.00, P=0.002] and odds ratio for women of 3.28 (95% CI: 1.23-8.74, P=0.018). Among older population, many features of SN parallel those of OVF.

Relationship between sex and clinical and imaging features of early axial spondyloarthritis: results from a 48 month follow-up (Italian arm of the SPondyloArthritis Caught Early (SPACE) study)

Objectives To assess the association between sex and clinical and disease activity indices, and X-rays and magnetic resonance imaging (MRI) features, in early-stage axial spondyloarthritis (axSpA). Method Baseline data analysis was conducted on the Italian SPACE cohort, including patients with chronic back pain (duration ≥ 3 months and ≤ 2 years; onset < 45 years). Patients underwent MRI and X-rays of the sacroiliac joints (SIJs) to establish the diagnosis of axSpA, according to Assessment of SpondyloArthritis international Society criteria and physician’s judgement. Clinical features, disease activity and functional indices, and images were collected at baseline and yearly during 48 months. Spinal and SIJ X-rays and MRI images were scored by two readers following Spondyloarthritis Research Consortium of Canada (SPARCC), modified Stoke Ankylosing Spondylitis Spinal Score, and modified New York criteria. Characteristics of axSpA patients according to sex (male/female) were compared over time using descriptive statistics. Results Ninety-one patients had axSpA (83.5% non-radiographic; 16.5% radiographic); 47.3% were male. Males were younger, with shorter duration of axial symptoms, and more frequently had HLA-B27 positivity, radiographic sacroiliitis with a bilateral/symmetric pattern, and more signs of spondylitis. Females more frequently showed peripheral/entheseal involvement and the non-radiographic phenotype. Males showed increased pelvic/spinal radiographic progression and more often had active sacroiliitis on MRI. Although the frequency of inflammatory corner lesions did not differ between males and females, localization varied, with more cervical/thoracic MRI-spine lesions in females and more lumbar lesions in males. We observed a significant downward trend of SPARCC SIJ/spine scores in all patients, irrespective of sex. More fat lesions were observed on MRI-spine in females and on MRI-SIJ in males. Conclusion Sex was associated with distinct axSpA features: females showed low-grade radiographic sacroiliitis and spinal progression, and a higher prevalence of cervical and thoracic spine MRI signs.

Transverse myelitis following bivalent COVID‐19 booster vaccine and quadrivalent seasonal influenza vaccine

Transverse myelitis following bivalent <scp>COVID</scp>‐19 booster vaccine and quadrivalent seasonal influenza vaccine