Additional Imaging Research Articles

Strategies for minimizing repeated exposures in diagnostic radiography

Advancements in diagnostic radiography have significantly improved medical imaging, yet the associated radiation exposure poses health risks, particularly with repeated examinations. Technological innovations, including the transition from analog to digital radiography, have led to substantial reductions in radiation doses while enhancing image quality. Digital systems, coupled with automatic exposure control (AEC), dynamically adjust radiation levels based on patient size and diagnostic requirements, minimizing unnecessary exposure. Iterative reconstruction algorithms in CT imaging further reduce radiation doses by efficiently processing images and reducing noise. Hardware improvements, such as high-efficiency detectors, capture high-quality images with lower radiation levels, contributing to dose reduction. Standardizing radiographic protocols across healthcare settings ensures consistent practices, reducing variability in radiation doses. Techniques such as beam collimation and appropriate shielding protect surrounding tissues and enhance image quality, while continuous education for technologists maintains proficiency in dose-reduction strategies. Patient education is crucial for minimizing repeated exposures. Informing patients about the risks of ionizing radiation and the importance of adhering to follow-up schedules can reduce unnecessary examinations. Electronic health records (EHRs) facilitate the tracking of cumulative radiation doses, enabling informed decision-making regarding additional imaging studies. Adherence to the ALARA principle (As low as reasonably achievable) in clinical practice ensures that radiation exposure is minimized while achieving diagnostic goals. Special considerations for vulnerable populations, such as children and pregnant women, further enhance safety. Implementing radiation safety measures and maintaining a commitment to ongoing professional development for healthcare providers fosters a culture of safety within radiology departments. By integrating these strategies, healthcare providers can balance the diagnostic benefits of radiography with the imperative to protect patients from unnecessary radiation exposure, ultimately enhancing patient safety and improving diagnostic outcomes. This comprehensive approach ensures that radiographic procedures remain both effective and safe, optimizing patient care in medical imaging.

Enhancing three-source cross-modality image fusion with improved DenseNet for infrared polarization and visible light images

The fusion of multi-modal images to create an image that preserves the unique features of each modality as well as the features shared across modalities is a challenging task, particularly in the context of infrared (IR)-visible image fusion. In addition, the presence of polarization and IR radiation information in images obtained from IR polarization sensors further complicates the multi-modal image-fusion process. This study proposes a fusion network designed to overcome the challenges associated with the integration of low-resolution IR, IR polarization, and high-resolution visible (VIS) images. By introducing cross attention modules and a multi-stage fusion approach, the network can effectively extract and fuse features from different modalities, fully expressing the diversity of the images. This network learns end-to-end mapping from sourced to fused images using a loss function, eliminating the need for ground-truth images for fusion. Experimental results using public datasets and remote-sensing field-test data demonstrate that the proposed methodology achieves commendable results in qualitative and quantitative evaluations, with gradient based fusion performance QAB/F, mutual information (MI), and QCB values higher than the second-best values by 0.20, 0.94, and 0.04, respectively. This study provides a comprehensive representation of target scene information that results in enhanced image quality and improved object identification capabilities. In addition, outdoor and VIS image datasets are produced, providing a data foundation and reference for future research in related fields.

Iodinated gadolinium-gold nanomaterial as a multimodal contrast agent for cartilage tissue imaging.

Cartilage damage, a common cause of osteoarthritis, requires medical imaging for accurate diagnosis of pathological changes. However, current instruments can acquire limited imaging information due to sensitivity and resolution issues. Therefore, multimodal imaging is considered an alternative strategy to provide valuable images and analyzes from different perspectives. Among all biomaterials, gold nanomaterials not only exhibit outstanding benefits as drug carriers, in vitro diagnostics, and radiosensitizers, but are also widely used as contrast agents, particularly for tumors. However, their potential for imaging cartilage damage is rarely discussed. In this study, we developed a versatile iodinated gadolinium-gold nanomaterial, AuNC@BSA-Gd-I, and its radiolabeled derivative, AuNC@BSA-Gd-131I, for cartilage detection. With its small size, negative charge, and multimodal capacities, the probe can penetrate damaged cartilage and be detected or visualized by computed tomography, MRI, IVIS, and gamma counter. Additionally, the multimodal imaging potential of AuNC@BSA-Gd-I was compared to current multifunctional gold nanomaterials containing similar components, including anionic AuNC@BSA, AuNC@BSA-I, and AuNC@BSA-Gd as well as cationic AuNC@CBSA. Due to their high atomic numbers and fluorescent emission, AuNC@BSA nanomaterials could provide fundamental multifunctionality for imaging. By further modifying AuNC@BSA with additional imaging materials, their application could be extended to various types of medical imaging instruments. Nonetheless, our findings showed that each of the current nanomaterials exhibited excellent abilities for imaging cartilage with their predominant imaging modalities, but their versatility was not comparable to that of AuNC@BSA-Gd-I. Thus, AuNC@BSA-Gd-I could be served as a valuable tool in multimodal imaging strategies for cartilage assessment.

Automated Opportunistic Osteoporosis Screening Using Low-Dose Chest CT among Individuals Undergoing Lung Cancer Screening in a Korean Population.

Opportunistic osteoporosis screening using deep learning (DL) analysis of low-dose chest CT (LDCT) scans is a potentially promising approach for the early diagnosis of this condition. We explored bone mineral density (BMD) profiles across all adult ages and prevalence of osteoporosis using LDCT with DL in a Korean population. This retrospective study included 1915 participants from two hospitals who underwent LDCT during general health checkups between 2018 and 2021. Trabecular volumetric BMD of L1-2 was automatically calculated using DL and categorized according to the American College of Radiology quantitative computed tomography diagnostic criteria. BMD decreased with age in both men and women. Women had a higher peak BMD in their twenties, but lower BMD than men after 50. Among adults aged 50 and older, the prevalence of osteoporosis and osteopenia was 26.3% and 42.0%, respectively. Osteoporosis prevalence was 18.0% in men and 34.9% in women, increasing with age. Compared to previous data obtained using dual-energy X-ray absorptiometry, the prevalence of osteoporosis, particularly in men, was more than double. The automated opportunistic BMD measurements using LDCT can effectively predict osteoporosis for opportunistic screening and identify high-risk patients. Patients undergoing lung cancer screening may especially profit from this procedure requiring no additional imaging or radiation exposure.

Heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) accounts for nearly half of all heart failure cases and has a prevalence that is expected to rise with the growing ageing population. HFpEF is associated with significant morbidity and mortality. Specific HFpEF risk factors include age, diabetes, hypertension, obesity and atrial fibrillation. Haemodynamic contributions to HFpEF include changes in left ventricular structure, diastolic and systolic dysfunction, left atrial myopathy, pulmonary hypertension, right ventricular dysfunction, chronotropic incompetence, and vascular dysfunction. Inflammation, fibrosis, impaired nitric oxide signalling, sarcomere dysfunction, and mitochondrial and metabolic defects contribute to the cellular and molecular changes observed in HFpEF. HFpEF impacts multiple organ systems beyond the heart, including the skeletal muscle, peripheral vasculature, lungs, kidneys and brain. The diagnosis of HFpEF can bemade in individuals with signs and symptoms of heart failure with abnormality in natriuretic peptide levels or evidence of cardiopulmonary congestion, facilitated by the use of HFpEF risk scores and additional imaging and testing with the exclusion of HFpEF mimics. Management includes initiation of guideline-directed medical therapy and management of comorbidities. Given the significant impact of HFpEF on quality of life, future research efforts should include a particular focus on how patients can live better with this disease.

Combined Supine-Prone Myocardial Perfusion Imaging: Enhancing Diagnostic Accuracy.

The combined supine-prone imaging protocol for SPECT myocardial perfusion imaging offers significant advantages over supine imaging alone. By comparing supine and prone images, one can distinguish attenuation artifacts in the inferior and anterior walls from true perfusion defects, thus improving specificity and diagnostic accuracy. The recommended protocol is to perform prone imaging after supine stress imaging when perfusion defects are noted. The additional prone imaging time is 20%-40% less than the standard supine imaging time. Implementing prone imaging can optimize patient care and provide substantial benefits for nuclear cardiology labs, especially those without attenuation correction.

Implementing a rapid cord compression Magnetic Resonance Imaging protocol in the emergency department: Lessons learned.

(1) Evaluate efficacy of an abbreviated total spine protocol in triaging emergency department (ED) patients through retrospective evaluation. (2) Describe patient outcomes following implementation of a rapid cord compression protocol. (1) All contrast-enhanced total spine magnetic resonance imaging studies (MRIs) performed on ED patients (n = 75) between 10/1-12/31/2022 for evaluation of cord compression were included. Two readers with 6 and 5years of experience blindly reviewed the abbreviated protocol (comprised of sagittal T2w and axial T2w sequences) assessing presence of cord compression or severe spinal canal stenosis. Ground truth was consensus by a neuroradiology fellow and 2 attendings. (2) The implemented rapid protocol included sagittal T1w, sagittal T2w Dixon and axial T2w images. All ED patients (n = 85) who were imaged using the rapid protocol from 5/1-8/31/2023 were included. Patient outcomes and call-back rates were determined through chart review. (1) Sensitivity and specificity for severe spinal canal stenosis and/or cord compression was 1.0 and 0.92, respectively, for reader 1 and 0.78 and 0.85, respectively, for reader 2. Negative predictive value was 1.0 and 0.97 for readers 1 and 2, respectively. (2) The implemented rapid cord compression protocol resulted in 60% reduction in imaging time at 1.5T. The call-back rate for additional sequences was 7%. In patients who underwent surgery, no additional MRI images were acquired in 82% of cases (9/11). Implementing an abbreviated non-contrast total spine protocol in the ED results in a low call-back rate with acquired MRI images proving sufficient for both triage and treatment planning in most patients.

October 7th Mass Casualty Attack in Israel: Injury Profiles of Hospitalized Casualties.

On Saturday, October 7th, approximately 3000 Hamas-led terrorists infiltrated Israel's southern border and attacked civilians and soldiers. Terrorists murdered close to 1200 people, abducted hundreds, and injured thousands. This surprise attack involved an unprecedented number of casualties. This article describes the injuries and outcomes of the hospitalized casualties. Hospitalized trauma casualties with an injury date of October 7 to 8, 2023, and with ICD9 E-codes E979 and E990 through E999, were extracted from the Israel National Trauma Registry. Demographic, injury, and hospital resource-use data were analyzed. A total of 630 hospitalized casualties (277 civilians and 353 soldiers) suffered from gunshot wounds (90%), explosion-related wounds (19%), and multiple injury mechanisms (16%). The median age for civilians was 33 years (ages <1-88) and 21 years for soldiers. The most frequently injured body regions were lower (49%) and upper (42%) extremities, abdominal (28%), and thoracic (23%) injuries. Four hundred thirty-one (68%) patients underwent surgery, of which 240 within 12 hours. Over half of the severe and critical (Injury Severity Score 16+) casualties were discharged to a rehabilitation center. In-hospital mortality rate was 2.5%. Israel's hospitals faced many challenges following the mega mass casualty incident, including the absorption, diagnosis, treatment, and rehabilitation of a massive number of casualties. Hospitals needed to immediately repurpose to provide additional imaging equipment and operating rooms. Additionally, the huge demand for rehabilitation resources necessitated immediate reorganization and transformation of existing medical facilities to accommodate the many casualties requiring rehabilitation. The injury details and outcomes from this mega mass casualty incident provide important information for planning and preparedness at local, regional, and national levels.

Gossypiboma secondary to ovariohysterectomy in a dog

In veterinary medicine, intra-abdominal foreign bodies are a possible secondary complication of surgical procedures. Gossypiboma is defined as a forgotten textile material after surgery and is considered rare in veterinary medicine because most cases go unreported. The objective of this work is to report the diagnosis of an intra-abdominal gossypiboma in a dog, secondary to theovaryhysterectomy procedure. A 10-year-old Labrador dog had been sterilized about eight years ago. During the clinical analysis, a firm-looking increase in volume was found in the right mesogastric region, without the presence of pain on palpation. For further investigation, the patient was referred for additional imaging tests, such as x-ray and ultrasound. During inspection of the abdominal cavity, a firm circular mass was observed adhered to the omentum and jejunum, caudal to the right kidney. Resection of the mass was performed, and then the mass sample was sent for histopathological examination, which revealed an encapsulated foreign body, consistent with surgical gauze. Gossypiboma is one of the possible complications in surgical procedures in the abdominal cavity, but it is rarely reported in the veterinary literature.

Chronic Thromboembolic Pulmonary Hypertension

: While the majority of patients have complete resolution of their acute pulmonary embolism (PE) after an adequate course of anticoagulation, some patients remain symptomatic with evidence of chronic PE. Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and Chronic Thromboembolic Pulmonary Disease (CTEPD) are terms that describe symptomatic patients with chronic thromboembolic occlusions of the pulmonary arteries with or without pulmonary hypertension, respectively. Here, we review the definitions, epidemiology, pathobiology, diagnosis and management of CTEPH. The chronic PE in CTEPH is essentially a scar in the pulmonary vasculature and is accompanied by a pulmonary arteriolar vasculopathy. Ventilation-perfusion scanning is the most sensitive screening test for CTEPH, and diagnosis must be confirmed by right heart catheterization (RHC). Treatment decisions require a multidisciplinary team and guidance from additional imaging, usually CT or pulmonary angiography. While pulmonary endarterectomy (PEA) to remove the chronic PE surgically is still the first-line treatment for appropriate candidates, there is an expanding role for balloon pulmonary angioplasty (BPA) and medical treatment, as well as multimodality treatment approaches that incorporate all of those options. New imaging modalities and treatment strategies hold the promise to improve our care and management of CTEPH patients in the future.

Detection of Contralateral Malignancies on Breast MRI.

Women with unilateral breast cancer are at increased risk for having simultaneous cancer of the contralateral breast. Overall, earlier detection of contralateral breast cancer prevents the burden of additional surgery or chemotherapy rounds and is associated with higher overall survival. However, MRI screening for the contralateral breast is seldom done following an initial unilateral breast cancer diagnosis. The purpose of this study is to retrospectively evaluate patients with known, biopsy-proven malignancy who went on to obtain a breast MRI and were later found to have cancer of the contralateral breast. Methods: This was a retrospective study that reviewed the charts of women aged over 18 years who were determined to have synchronous bilateral breast cancer from January 2017 to January 2022 at the University of Florida, Gainesville, FL. The study extracted data from this institution's cancer registry database, which provided information on patients with breast cancer diagnoses. The study conducted a review of mammography (MAM) and MRI imaging reports to ascertain the presence or absence of contralateral breast cancer identified by each respective imaging modality. Surgical pathology reports from the biopsy of the contralateral breast were reviewed to obtain information on the histological type of cancer and TNM (tumor, node, metastasis) staging. Of the 17 cases in which MAM missed contralateral cancer, follow-up MRI detected contralateral malignancy in 12 cases (70.59%) and subsequently changed management, resulting in additional imaging, biopsy, and eventual diagnosis and treatment of contralateral breast cancer. Examining the number of contralateral breast cancers detected by patients who had undergone MAM followed by MRI and those who had only undergone MAM, the study found that the detection rate of contralateral breast cancer from MAM was 45.45% (15/33). The tumor stages of the missed cancers were all T1 or Tis stage with one T1mi, and there was no nodal involvement. Conclusion: In addition to its utility in staging breast cancers, MRI also has the superior ability to detect otherwise undetected contralateral breast malignancy. This retrospective study found that MRI imaging led to a considerable increase in the detection of contralateral cancer. The study found that these undetected contralateral breast cancers by MAM were often of lower staging with no nodal involvement, highlighting the opportunity for MRI to assist in early cancer detection while the patient's prognosis is still good. Its high cost should be balanced with staging and occult malignancy detection utility in future practice.

Pain Experience and Image Quality with Curved versus Standard Compression for Breast Cancer Screening Mammography: A Randomized Controlled Trial.

Background A curve-shaped compression paddle could reduce the pain experienced by some women at breast cancer screening. Purpose To compare curved and standard compression systems in terms of pain experience and image quality in mammography screening. Materials and Methods In this randomized controlled trial conducted between October 2021 and February 2022, participants screened at three screening sites in the Netherlands were randomized to either a curved-paddle or sham-paddle group. The sham paddle was a standard paddle that was presented as a new paddle. At a standard screening examination, one additional image was acquired with a curved or sham paddle. Pain was measured on a numerical rating scale (range, 0-10). Participants provided a pain score after compression with the standard and test paddles, resulting in two scores per participant. Differences in pain scores were compared between groups using analysis of covariance, adjusting for pain score after standard-paddle compression. Two radiographers and two radiologists performed unblinded paired comparisons of curved-paddle vs standard-paddle images, using standard image quality criteria (radiographers evaluated 1246 image pairs using 12 criteria; radiologists evaluated 320 image pairs using six criteria). The one-sample Wilcoxon signed-rank test was used to determine if there was a significant preference for either paddle. Results In total, 2499 female participants (mean age, 61.6 years ± 7.1 [SD]) were studied; 1250 in the curved-paddle group and 1249 in the sham-paddle group. The mean pain score decreased by an additional 0.19 points in the curved-paddle group compared with the sham-paddle group (95% CI: 0.09, 0.28; P < .001). In terms of image quality, the observers showed no preference or a preference for the standard paddle. Decreased image contrast (range Bonferroni-corrected P values: P < .001 to P > .99) and visibility of structures were the main concerns for curved-paddle images. Conclusion The use of the curved paddle resulted in a minimal pain reduction during mammography breast compression but image quality was reduced. © RSNA, 2024 Supplemental material is available for this article.

Mammography and Breast Ultrasonography Services in Ghana, Availability, and Geographic Access.

Breast cancer is the leading type of cancer diagnosed and the second leading cause of cancer-related death in Ghana. Mammography and ultrasound have proven benefits in the early detection of breast cancer. This study evaluates mammography, breast ultrasound, and radiology work force availability throughout Ghana. A survey was administered to all hospitals in Ghana from November 2020 to October 2021. Mammography, breast ultrasound services, and the number of radiologists were assessed. For mammography, the number performed per month, cost incurred by the patient, where images were read, and how long it took to receive reports were also assessed. Health Facilities Regulatory Authority records on diagnostic centers were obtained to identify additional in-country breast imaging services. Three hundred and twenty-eight of 346 hospitals participated in the survey (95%). Only 21 hospitals reported on-site mammography. One hospital reported performing >100 mammographies per month. The average cost to the patient ranged from 100 to 500 Cedis ($17-87 US dollars [USD]), although three hospitals performed mammography at no cost. An additional 10 mammography machines were identified at diagnostic centers throughout the country, with 41.3% of the female population living within 1 hour of mammography services. There were 135 hospital-based breast ultrasound services identified with 69.5% of the female population living within 1 hour of these services. There were an additional 190 ultrasound machines at diagnostic centers. There were 96 in-country radiologists identified. Although there is limited availability and utilization of mammography in Ghana, there is more readily available ultrasonography. A focus on increasing breast cancer early diagnostic capabilities with breast ultrasound should be prioritized in addition to further expansion of the radiology workforce.

Load-dependent optical coherence tomography attenuation imaging: How tissue mechanics can influence optical scattering

Mechanical load imparted to tissue, for example via handheld imaging probes, leads to tissue deformation, altering the distribution of tissue microstructure and, consequently, attenuation of light and image formation in optical imaging. In mechanically heterogeneous tissue, the load can result in spatially varying deformation and, therefore, spatially varying changes in the attenuation of light, which may provide additional image contrast. To investigate this potential, an assessment of the spatially resolved impact of mechanical deformation of the tissue on optical imaging is critical; however, it is challenging to incorporate stress mapping into optical imaging without obscuring the detection of photons. To address this, we present the novel integration of stress imaging using optical palpation with attenuation imaging based on optical coherence tomography (OCT). The method was implemented using a compliant silicone sensor incorporated into a custom handheld OCT probe, providing two-dimensional stress imaging with concurrent attenuation imaging. Attenuation imaging with varying mechanical loads was demonstrated on 19 tissue regions acquired from eight freshly excised human breast specimens. The results demonstrated distinct characteristics for different breast tissue types: benign stroma showed relatively large increases in attenuation (e.g., ∼0.3 to 0.4 mm−1/kPa) over a low stress range (∼2 to 10 kPa), while cancerous tissue showed markedly small increases in attenuation (e.g., ∼0.005 to 0.02 mm−1/kPa) mainly over a medium to high stress range (∼10 to 90 kPa). The integration of stress imaging with attenuation imaging provided a pilot assessment of the spatially resolved impact of tissue mechanical heterogeneity on optical attenuation, providing novel image contrast by encoding variations in mechanical properties on optical attenuation in tissue.

Systematic Biopsy vs. Prostatectomy: Evaluating Correlations and Grading Discrepancies in Prostate Cancer.

Background Prostate Cancer (PCa) represents agrowing global health challenge. The main factor in predicting PCa prognosis is represented by the Gleason Score (GS)therefore, the accuracy of pathological features from preoperative biopsy is critical in the management of the patient. We aimed to investigate the correlation between prostate biopsy parameters and the prostatectomy specimen pathological features and to identify factors that lead to over- and under-grading tumors in biopsy samples. Materials and methods We performed a retrospective study that included 110 male patients with confirmed PCa, selected based on specific inclusion criteria. Biopsy and radical prostatectomy (RP) specimens were analyzed using standard histopathological techniques, and pathological features were assessed according to the latest guidelines. Statistical analysis was performed using IBM SPSS Statistics version 26.0.0 (IBM Corp., Armonk, NY). Results The study included 110 male patients with a median age of 67 years old, ranging from 48 to 79 years old. Correlations between biopsy parameters and RP outcomes were assessed and revealed several key findings. The tumoral length on biopsy was correlated with positive surgical margin (r=0.289, p<0.01) and with tumoral volume (r=0.526, p<0.001) on prostatectomy. Patients with higher grade groups (GG) on biopsy had an approximately four times higher chance of exhibiting extraprostatic extension. We demonstrated a significant correlation between Gleason Pattern 4 (%GP4) on biopsy and pT stage, with pT4 showing the highest %GP4, and a noticeable increase in %GP4 as the pT stage progressed from pT2b to pT4. The study found a significantly higher rate of undergrading at biopsy (30.90%) compared to overgrading (6.36%). Additionally, greater tumor length and higher tumor percentages in biopsies improved grading accuracy (p<0.001). Conclusion Our findings suggest that systemic biopsies play a key role in predicting pathological outcomes, especially through parameters that serve as key prognostic markers. However, due to the potential of the biopsy results to be under- or overgraded, urologists should take into consideration the advantages of using repeat biopsies or additional imaging techniques to achieve a more precise diagnosis and treatment strategy.

Demonstration of VCR: A Tabular Data Slicing Approach to Understanding Object Detection Model Performance

In this demonstration, we present VCR, an automated slice discovery method (SDM) for object detection models that helps practitioners identify and explain specific scenarios in which their models exhibit systematic errors. VCR leverages the capabilities of vision foundation models to generate segment-level visual concepts that serve as interpretable explanation primitives. By integrating these visual concepts with additional image metadata in a tabular format, VCR uses a scalable frequent itemset mining-based technique to identify common patterns associated with model performance. We will demonstrate VCR's capabilities through three usage scenarios. First, users can explore the automatically extracted visual concepts and their associated labels. Second, users can run slice finding on a large object detection dataset and visually inspect the results to discover systematic errors. Finally, users can iteratively refine their slicing results by providing feedback on the granularity of visual concepts and the quality of the generated labels. These scenarios will illustrate how VCR can aid practitioners in discovering non-trivial gaps in their models' performance, providing actionable insights for model improvement.

Large-scale calcium imaging reveals a systematic V4 map for encoding natural scenes

Biological visual systems have evolved to process natural scenes. A full understanding of visual cortical functions requires a comprehensive characterization of how neuronal populations in each visual area encode natural scenes. Here, we utilized widefield calcium imaging to record V4 cortical response to tens of thousands of natural images in male macaques. Using this large dataset, we developed a deep-learning digital twin of V4 that allowed us to map the natural image preferences of the neural population at 100-µm scale. This detailed map revealed a diverse set of functional domains in V4, each encoding distinct natural image features. We validated these model predictions using additional widefield imaging and single-cell resolution two-photon imaging. Feature attribution analysis revealed that these domains lie along a continuum from preferring spatially localized shape features to preferring spatially dispersed surface features. These results provide insights into the organizing principles that govern natural scene encoding in V4.

Parcel-Based Sugarcane Mapping Using Smoothed Sentinel-1 Time Series Data

The timely and accurate mapping of sugarcane cultivation is significant to ensure the sustainability of the sugarcane industry, including sugarcane production, rural society, sugar futures, and crop insurance. Synthetic aperture radar (SAR), due to its all-weather and all-time imaging capability, plays an important role in mapping sugarcane cultivation in cloudy areas. However, the inherent speckle noise of SAR data worsens the “salt and pepper” effect in the sugarcane map. Therefore, in previous studies, an additional land cover map or optical image was still required. This study proposes a new application paradigm of time series SAR data for sugarcane mapping to tackle this limitation. First, the locally estimated scatterplot smoothing (LOESS) smoothing technique was exploited to reconstruct time series SAR data and reduce SAR noise in the time domain. Second, temporal importance was evaluated using RF MDA ranking, and basic parcel units were obtained only based on multi-temporal SAR images with high importance values. Lastly, the parcel-based classification method, combining time series smoothing SAR data, RF classifier, and basic parcel units, was used to generate a sugarcane extent map without unreasonable sugarcane spots. The proposed paradigm was applied to map sugarcane cultivation in Suixi County, China. Results showed that the proposed paradigm was able to produce an accurate sugarcane cultivation map with an overall accuracy of 96.09% and a Kappa coefficient of 0.91. Compared with the pixel-based classification result with original time series SAR data, the new paradigm performed much better in reducing the “salt and pepper” spots and improving the completeness of the sugarcane plots. In particular, the unreasonable non-vegetation spots in the sugarcane map were eliminated. The results demonstrated the efficacy of the new paradigm for mapping sugarcane cultivation. Unlike traditional methods that rely on optical remote sensing data, the new paradigm offers a high level of practicality for mapping sugarcane in large regions. This is particularly beneficial in cloudy areas where optical remote sensing data is frequently unavailable.

Primary BAP1-absent atypical meningioma arising from median nerve within infraclavicular brachial plexus: illustrative case.

The authors present the only known case of a World Health Organization grade II ectopic meningioma occurring in the infraclavicular brachial plexus, causing pain within the axilla not associated with a primary malignant meningioma of the central nervous system. Peripheral nerve sheath tumors are rare entities, the majority of which are schwannomas or neurofibromas. Ectopic meningiomas only represent 1%-2% of all meningiomas. To date, there is one other published case specifically of a primary ectopic meningioma located in the brachial plexus. Following the dissection of the left axilla, a dominant rubbery tumor involving the median nerve was encountered. The tumor capsule contained areas of hemorrhage and a soft core with nerve fascicles coursing through, which were not compromised during internal tumor debulking. The tumor lacked a clear pseudocapsule that is characteristically seen in schwannomas. Histopathological studies confirmed an atypical epithelioid neoplasm with elevated numbers of mitotic figures and BAP1 gene deletion. Primary meningiomas arising outside the central nervous system are exceedingly rare. For this unusual higher-grade primary ectopic meningioma located in the distal brachial plexus, surgery with the goal of gross-total resection, adjuvant radiation, additional imaging, and genetics screening were recommended. Close follow-up is warranted. https://thejns.org/doi/10.3171/CASE24226.

The "Hypointense Focal Brain" on susceptibility-weighted imaging as a sign of venous congestion in cranial dural arteriovenous fistulas.

Cranial dural arteriovenous fistulas (dAVFs) are complex neurovascular malformations accounting for approximately 10%-15% of all intracranial arteriovenous malformations. The objective is to investigate the utility of susceptibility-weighted imaging (SWI) in identifying "hypointense focal brain" as an additional helpful sign of venous congestion in cranial dAVFs. A retrospective review of patients diagnosed with cranial dAVFs between January 2015 and June 2023 was conducted, and SWI was used to identify the "hypointense focal brain" sign within the venous drainage region of the dAVF. The "hypointense focal brain" on SWI was identified as a low-intensity signal within the venous drainage region, indicative of venous congestion. The presence of this imaging sign was assessed by two neuroradiologists and signal intensity measurements were performed to support the presence of the sign. The study included six patients with cranial dAVFs exhibiting cortical venous retrograde drainage and the "hypointense focal brain" on SWI. Follow-up imaging post-treatment revealed resolution or improvement of the hypointense signal, confirming its association with venous congestion. Signal intensity measurements further supported the presence of this imaging sign in pre-treatment scans. The study's findings demonstrate the presence of a reversible "hypointense focal brain" sign on SWI in patients with cranial dAVFs and CVR, which can be useful as an additional imaging sign for venous congestion.