Imaging Modalities Research Articles

HaptiScan: A Haptically-Enabled Robotic Ultrasound System for Remote Medical Diagnostics

Medical ultrasound is a widely used diagnostic imaging modality that provides real-time imaging at a relatively low cost. However, its widespread application is hindered by the need for expert operation, particularly in remote regional areas where trained sonographers are scarce. This paper presents the development of HaptiScan, a state-of-the-art telerobotic ultrasound system equipped with haptic feedback. The system utilizes a commercially available robotic manipulator, the UR5 robot from Universal Robots, integrated with a force/torque sensor and the Phantom Omni haptic device. This configuration enables skilled sonographers to remotely conduct ultrasound procedures via an internet connection, addressing both the geographic and ergonomic limitations faced in traditional sonography. Key innovative features of the system include real-time force feedback, ensuring that sonographers can precisely control the ultrasound probe from a remote location. The system is further enhanced by safety measures such as over-force sensing, patient discomfort monitoring, and emergency stop mechanisms. Quantitative indicators of the system’s performance include successful teleoperation over long distances with time delays, as demonstrated in simulations. These simulations validate the system’s control methodologies, showing stable performance with force feedback under varying time delays and distances. Additionally, the UR5 manipulator’s precision, kinematic, and dynamic models are mathematically formulated to optimize teleoperation. The results highlight the effectiveness of the proposed system in overcoming the technical challenges of remote ultrasound procedures, offering a viable solution for real-world telemedicine applications.

Ultrasound and computed tomography in differentiating between simple and complicated appendicitis in pediatric patients.

This study aims to measure the diagnostic accuracy and reliability of US and CT in diagnosing complicated appendicitis among pediatric patients and to find the performance of the imaging modalities in detecting complication signs. a systematic review and meta-analysis were done on 15 eligible studies from the Medline Database concerning pediatric appendicitis and its complications. Studies either provided an overall estimate of sensitivity and specificity of the imaging modality or addressed signs of complicated appendicitis The reference standard employed was either surgical findings or histopathology reports. The review included assessments of 4,497 pediatric patients, with 285 undergoing CT and 4,212 undergoing US imaging. CT demonstrated sensitivities of 62% and 68.4%, and specificities of 81% and 92.4%. US showed sensitivities of 33.9% to 51.5% and specificities ranging from 68.8% to 95%. The ultrasound's ability to detect appendiceal wall diameter > 5mm showed the highest sensitivity (99.4%), while the conglomerate sign indicated the highest specificity (99.9%). The findings suggest that both US and CT exhibit higher specificity than sensitivity in diagnosing complicated appendicitis in pediatric patients. Given its favorable specificity, non-invasiveness, and lack of radiation exposure, US should be the first-line imaging modality in suspected cases of pediatric appendicitis. CT, offering robust specificity, should be reserved for ambiguous cases where US results are inconclusive. These insights underscore the critical role of precise imaging modalities in enhancing diagnostic accuracy, reducing unnecessary surgeries, and improving clinical outcomes in pediatric appendicitis management.

Evaluating the Diagnostic Potential of Four-Dimensional Flow Magnetic Resonance Imaging in Aortic Stenosis Diagnosis: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis evaluates the potential of four-dimensionalflow magnetic resonance imaging(4DFM) in assessing aortic stenosis (AS) compared to traditional imaging modalities like two-dimensional phase contrast MRI (2D MRI) and transthoracic echocardiography (TTE). AS is a common and severe valvular heart disease, particularly in older adults, requiring accurate diagnosis for proper clinical management. Conventional imaging methods have limitations in capturing complex flow dynamics, prompting the need for advanced modalities like 4DFM. The objectives of the review were to determine whether 4DFM offers superior diagnostic metrics, including peak aortic jet velocity, transvalvular pressure gradients, and aortic valve area (AVA), and to identify potential advantages of 4DFM in overcoming the limitations of traditional modalities. This review included six cohort studies with 285 participants, examining the diagnostic accuracy of 4DFM in terms of peak aortic jet velocity, transvalvular pressure gradients, and aortic valve area (AVA). Studies were selected from MEDLINE (PubMed), Cochrane Library, and Google Scholar databases between December 2010 and October 2024. The study pool was limited by stringent inclusion criteria focusing on cohort studies that directly compared 4DFM with TTE or 2D MRI for AS assessment. The National Institutes of Health Quality Assessment Tool and Cochrane ROBINS-I tool were used to assess bias. Quantitative results showed that 4DFM typically measured higher AVA values than TTE, with a mean difference of 0.48 cm² (95% CI: -0.16 to 1.12). For mean pressure gradients, 4DFM reported slightly higher measurements in individual studies, but pooled results showed no significant difference compared to TTE (mean difference: 3.32 mmHg, 95% CI: -2.30 to 8.93). In terms of peak aortic jet velocity, 4DFM demonstrated a pooled mean difference of -0.18 m/s (95% CI: -0.44 to 0.08) compared to TTE. High heterogeneity was observed across studies (e.g., I² = 97% for peak velocity, I² = 93% for AVA), likely due to differences in patient populations, imaging protocols, and software for data analysis.4DFM demonstrates potential as a complementary imaging tool, particularly in complex AS cases where conventional methods like TTE may provide inconclusive results. Its capacity to capture intricate flow dynamics and deliver high spatial resolution could inform clinical decision-making, potentially influencing practice guidelines to integrate 4DFM as a supplementary tool. Limitations such as high costs, specialized training requirements, and access challenges currently restrict widespread adoption. Limitations of this review include small sample sizes, high heterogeneity, and variability in patient populations and imaging protocols. Despite these challenges, 4DFMI demonstrated superior spatial resolution and complex cardiovascular flow assessment, suggesting it could serve as a valuable complement to TTE for more detailed AS evaluation, particularly in complex cases.Future studies should aim to standardize imaging protocols, incorporate larger and more diverse populations, and conduct cost-benefit analyses to support the integration of 4DFM into clinical practice, potentially shaping future diagnostic guidelines.

Advancements in imaging of head and neck squamous cell carcinoma: A comprehensive review.

As a prevalent malignancy with substantial incidence and mortality worldwide, head and neck squamous cell carcinoma (HNSCC) originates from multiple locations of different tissues, which level up the difficulty and complexity of the cancer detection. The diagnosis requires highresolution imaging modalities and several approaches have been developed within recent decades to provide detailed anatomical information for HNSCC.

Expert consensus on workflow of PET/CT with long axial field-of-view.

Positron emission tomography/computed tomography (PET/CT) imaging has been widely used in clinical practice. Long axial field-of-view (LAFOV) systems have enhanced clinical practice by leveraging their technological advantages and have emerged as the new state-of-the-art PET imaging modalities. A consensus was conducted to explore expert views in this emerging field to comprehensively elucidate the proposed workflow in LAFOV PET/CT examinations and highlight the potential challenges inherent in the workflow. A multidisciplinary task group formed by 28 experts from six countries over the world discussed and approved the consensus based on the published guidelines, peer-reviewed articles of LAFOV PET/CT, and the collective experience from clinical practice. This consensus focuses on the workflow that allows for a broader range of imaging protocols of LAFOV PET/CT, catering to diverse patient needs and in line with precision medicine principles. This consensus describes the workflows and imaging protocols of LAFOV PET/CT for various imaging scenarios including routine static imaging, dynamic imaging, low-activity imaging, fast imaging, prolonged imaging, delayed imaging, and dual-tracer imaging. In addition, imaging reconstruction and reviewing specific to LAFOV PET/CT imaging, as well as the main challenges facing installation and application of LAFOV PET/CT scanner were also summarized. This consensus summarized the various imaging workflow, imaging protocol, and challenges of LAFOV PET/CT imaging, aiming to enhance the clinical and research applications of these scanners.

CBCT Guidance for Removing Foreign Object from the Jawbone: A Case Study

AbstractForeign objects lodged in the mandibular bone often result from trauma or dental procedures. Accurate localization of these foreign objects is crucial for guided surgical removal, especially when patients present with persistent pain. Conventional imaging modalities like periapical and panoramic radiographs may not provide sufficient detail for precise localization. Cone beam computed tomography (CBCT) has emerged as a valuable tool for guided surgical interventions owing to its superior imaging capabilities. We present two cases of foreign objects lodged in the mandible, where patients complained of prolonged pain, soreness, and numbness in the right mandible extending to the head and behind the ear. Both patients had undergone previous right mandibular tooth extractions and received treatment from a neurologist without resolution of symptoms. Both cases showed the control improvement in complaints, and no paresthesia or postoperative complications were found. CBCT-guided surgical removal was performed in both cases, revealing a metal specimen measuring 6 × 3 × 1 mm3 in the first patient and a remaining root measuring 5 × 3 × 2 mm3 in the second patient. Diagnosing foreign objects in the mandible poses challenges due to their varied size, composition, and proximity to vital structures. CBCT offers superior imaging resolution, enabling precise localization and assessment of anatomical relationships, such as the distance to the inferior alveolar nerve and surrounding boundaries. CBCT emerges as the preferred imaging modality for diagnosing and guiding the surgical removal of foreign objects in the mandible. Its advantages include accurate localization, low radiation exposure, and cost-effectiveness. Compared with CT scans, CBCT also offers faster scanning times, making it a valuable tool in clinical practice for managing such cases

New insights on extramedullary granulopoiesis and neutrophil heterogeneity in the spleen and its importance in disease.

Neutrophils are traditionally viewed as uncomplicated exterminators that arrive quickly at sites of infection, kill pathogens, and then expire. However, recent studies employing modern transcriptomics coupled with novel imaging modalities have discovered that neutrophils exhibit significant heterogeneity within organs and have complex functional roles ranging from tissue homeostasis to cancer and chronic pathologies. This has revised the view that neutrophils are simplistic butchers, and there has been a resurgent interest in neutrophils. The spleen was described as a granulopoietic organ more than 4 decades ago, and studies indicate that neutrophils are briefly retained in the spleen before returning to circulation after proliferation. Transcriptomic studies have discovered that splenic neutrophils are heterogeneous and distinct compared with those in blood. This suggests that a unique hematopoietic niche exists in the splenic microenvironment, i.e., capable of programming neutrophils in the spleen. During severe systemic inflammation with an increased need of neutrophils, the spleen can adapt by producing neutrophils through emergency granulopoiesis. In this review, we describe the structure and microanatomy of the spleen and examine how cells within the splenic microenvironment help to regulate splenic granulopoiesis. A focus is placed on exploring the increase in splenic granulopoiesis to meet host needs during infection and inflammation. Emerging technologies such as single-cell RNA sequencing, which provide valuable insight into splenic neutrophil development and heterogeneity, are also discussed. Finally, we examine how tumors subvert this natural pathway in the spleen to generate granulocytic suppressor cells to promote tumor growth.

Artificial intelligence-enhanced infrared thermography as a diagnostic tool for thyroid malignancy detection

Introduction Thyroid nodules are common, and investigation is crucial for excluding malignancy. Increased intranodular vascularity is frequently observed in malignant tumors, which can be detected through increased skin surface temperatures using noninvasive infrared thermography. We aimed to develop a diagnostic tool for thyroid cancer using infrared thermal images combined with an artificial intelligence (AI) algorithm. Methods We conducted a prospective cross-sectional study involving participants with thyroid nodules undergoing thyroid surgery. Infrared thermal images were collected using a thermal camera on the day prior to surgery. In combination with the final thyroid pathological reports, we utilized a machine learning model based on the pre-trained ResNet50V2 model, a convolutional neural network, to evaluate diagnostic accuracy for malignancy diagnosis. Results The study included 98 participants, 58 with malignant thyroid nodules and 40 with benign thyroid nodules, as determined by pathological results. The AI-enhanced infrared thermal image analyses demonstrated good performance in distinguishing between benign and malignant thyroid nodules, achieving an accuracy of 75% and a sensitivity of 78%. These parameters were slightly lower than those of the AI-model predictor that integrated current practice using preoperative thyroid ultrasound findings and cytological results, yielding an accuracy of 81% and a sensitivity of 84%. Conclusions The infrared thermal images, assisted by an AI model, exhibit good performance in distinguishing thyroid malignancy from benign nodules. This imaging modality has great potential to be used as a noninvasive screening tool for adjunct evaluation of thyroid nodules.

Deep learning for 3D vascular segmentation in hierarchical phase contrast tomography: a case study on kidney

Automated blood vessel segmentation is critical for biomedical image analysis, as vessel morphology changes are associated with numerous pathologies. Still, precise segmentation is difficult due to the complexity of vascular structures, anatomical variations across patients, the scarcity of annotated public datasets, and the quality of images. Our goal is to provide a foundation on the topic and identify a robust baseline model for application to vascular segmentation using a new imaging modality, Hierarchical Phase-Contrast Tomography (HiP-CT). We begin with an extensive review of current machine-learning approaches for vascular segmentation across various organs. Our work introduces a meticulously curated training dataset, verified by double annotators, consisting of vascular data from three kidneys imaged using HiP-CT as part of the Human Organ Atlas Project. HiP-CT pioneered at the European Synchrotron Radiation Facility in 2020, revolutionizes 3D organ imaging by offering a resolution of around 20 μm/voxel and enabling highly detailed localised zooms up to 1–2 μm/voxel without physical sectioning. We leverage the nnU-Net framework to evaluate model performance on this high-resolution dataset, using both known and novel samples, and implementing metrics tailored for vascular structures. Our comprehensive review and empirical analysis on HiP-CT data sets a new standard for evaluating machine learning models in high-resolution organ imaging. Our three experiments yielded Dice similarity coefficient (DSC) scores of 0.9523, 0.9410, and 0.8585, respectively. Nevertheless, DSC primarily assesses voxel-to-voxel concordance, overlooking several crucial characteristics of the vessels and should not be the sole metric for deciding the performance of vascular segmentation. Our results show that while segmentations yielded reasonably high scores-such as centerline DSC ranging from 0.82 to 0.88, certain errors persisted. Specifically, large vessels that collapsed due to the lack of hydrostatic pressure (HiP-CT is an ex vivo technique) were segmented poorly. Moreover, decreased connectivity in finer vessels and higher segmentation errors at vessel boundaries were observed. Such errors, particularly in significant vessels, obstruct the understanding of the structures by interrupting vascular tree connectivity. Our study establishes the benchmark across various evaluation metrics, for vascular segmentation of HiP-CT imaging data, an imaging technology that has the potential to substantively shift our understanding of human vascular networks.

The Quantitative Impact of Prostate Specific Membrane Antigen Positron Emission Tomography/Computed Tomography (PSMA PET/CT) staging in Newly Diagnosed Metastatic Prostate Cancer and Treatment-Decision Implications

Abstract Objectives To quantify the stage-shift with PSMA PET/CT imaging in metastatic prostate cancer and explore treatment implications. Methods Single-centre, retrospective analysis of patients with newly diagnosed [18F]PSMA-1007 or [68Ga]Ga-PSMA-11 PET/CT-detected metastatic prostate cancer who had baseline bone scintigraphy between January 2015 and May 2021. Patients were subclassified into oligometastatic and polymetastatic disease utilising the STAMPEDE2 trial (ISRCTN66357938/NCT06320067) definition. Patient, tumour, and treatment characteristics were collected. PSMA PET/CT concordance with conventional imaging (bone scintigraphy and low-dose CT of PET) was identified by number and site of metastases, and subgroup assigned. Spearman’s rank correlation and linear regression modelling determined the association between the imaging modalities. Results We analysed 62 patients with a median age was 72 years (range 48-86). On PSMA PET/CT, 31/62 (50%) patients had oligometastatic disease, and 31/62 (50%) had polymetastatic disease. Prostate radiotherapy was delivered in 20/31 (65%) patients with oligometastatic disease and 17/31 (55%) with polymetastatic disease. 23/62 (37%) patients were reclassified as M0 on conventional imaging. PSMA PET/CT had a 2.9-fold increase in detecting bone metastases. Bone metastases concordance was found in 10/50 (20%) by number and 30/33 (91%) by site. PSMA PET/CT had a 2.2-fold increase in detecting nodal metastases. Nodal metastases concordance was found in 5/46 (11%) by number and 25/26 (96%) by site. There was significant positive correlation between PSMA PET/CT and conventional imaging for detecting bone (R2= 0.25 [p < 0.001]) and nodal metastases (R2= 0.19 [p < 0.001]). 16/31 (52%) had oligometastatic disease concordance. Conclusion The magnitude of PSMA PET/CT-driven stage-shift is highly variable and unpredictable with implications on treatment decisions, future trial design and potentially clinical outcomes.

Diagnostic Value of Maximal Systolic Acceleration Measurements in the Follow-up of Complex Endovascular Aortic Repair: Illustration of a Concept.

After complex endovascular aortic repair (cEVAR), long-term surveillance is advocated to monitor for potential (stent-related) complications. Although various imaging modalities are used, computed tomography angiography remains the standard in current clinical practice worldwide. However, radiopaque markers can cause metal artifacts and scattering, hampering assessment of patency of side branches. The maximal systolic acceleration (ACCmax) is a relatively new duplex ultrasound (DUS) parameter measured distal to a stenosis, avoiding in-stent assessment and scattering. The aim of this article is to illustrate the potential diagnostic utility of the ACCmax after cEVAR and visceral artery stenting in general. The ACCmax is measured at the maximal slope of the upstroke during the systolic phase in arterial flow. By manually connecting 2 points, a tangent line is created in which the maximal acceleration is automatically calculated and expressed in m/s2. A higher value reflects better arterial perfusion proximal to its measurement point. One measurement of a visceral artery takes about 5 minutes. ACCmax measurements can be a useful addition during DUS follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity, and health care costs. Long-term surveillance after complex endovascular aortic repair (cEVAR) is necessary to monitor for potential (stent-related) complications. Although CTA is the most common modality for imaging, metal artifacts and scattering can hamper the assessment of stent patency. The maximal systolic acceleration (ACCmax) is a duplex ultrasound based parameter that reflects arterial perfusion proximal to its measurement point. Due to its noninvasive nature, it can be a useful addition during follow-up after cEVAR or visceral artery stenting, possibly decreasing radiation exposure, nephrotoxicity and health care costs as well.

Efficacy of additional lateral pinhole and SPECT/CT imaging in dual-phase Tc-99m MIBI parathyroid scintigraphy for localising parathyroid pathologies in patients with primary hyperparathyroidism: a single-institution experience.

Parathyroid imaging with dual-phase technetium-99m methoxyisobutrylizonitrile (Tc-99m MIBI) scintigraphy serves as an important prerequisite for the identification of hyperfunctioning parathyroid gland(s) in patients with primary hyperparathyroidism (PHPT) for a successful targeted parathyroidectomy. This study aimed to evaluate the clinical value of additional lateral imaging and single-photon emission computed tomography/computed tomography (SPECT/CT) versus conventional planar imaging for locating parathyroid pathologies in patients with PHPT. A retrospective review was performed on 105 patients who underwent dual-phase Tc-99m MIBI scintigraphy and were surgically treated by parathyroidectomy. Dual-phase Tc-99m-MIBI planar scintigraphy with additional lateral pinhole views and SPECT/CT imaging was performed on a routine basis, as per departmental protocol. Comparison study between imaging modalities was done by patient-based analysis and scintigraphy results were compared with the clinical findings, biochemical markers, and histopathological findings. Sensitivity and specificity for anterior planar dual-phase Tc-99m MIBI scintigraphy were 78.8 and 80%, respectively. In comparison, lateral pinhole scan and SPECT/CT alone were found to have sensitivities of 85.9 and 90.9%, respectively, with the same specificity. Sensitivity decreased in patients with normocalcaemia and multiglandular disease. The mean adenoma weight and size for true-positive studies were significantly higher than those for false-negative or false-positive studies. SPECT/CT provided the highest diagnostic accuracy for preoperative identification of parathyroid lesions in PHPT patients. Lateral pinhole imaging offers comparable sensitivity and aids in adenoma localisation when SPECT/CT is unavailable.

Assessment of Reason for Exam Imaging Reporting and Data System (RI-RADS) in inpatient diagnostic imaging referrals

ObjectivesTo test the Reason for Exam Imaging Reporting and Data System (RI-RADS) in assessing the quality of radiology requests in an Italian cohort of inpatients; to evaluate the interobserver reliability of RI-RADS.MethodsA single-center quality care study was designed to retrospectively identify consecutive radiology request forms for computed tomography, magnetic resonance imaging, and conventional radiography examinations. One radiologist scored the requests using the RI-RADS. The association between RI-RADS and clinical request variables (urgent request, on-call requests, indication for imaging, requesting specialty, imaging modality, and body region) was evaluated. We calculated interobserver agreement between four readers in a subset of 450 requests.ResultsWe included 762 imaging requests. RI-RADS grades A (adequate request), B (barely adequate request), C (considerably limited request), D (deficient request), and X were assigned to 8 (1%), 49 (7%), 237 (31%), 404 (53%), and 64 (8%) of cases, respectively. In the multivariate analysis, the indication for imaging, body region, and requesting specialty significantly influenced the RI-RADS. Indications for imaging with a high risk of poor RI-RADS grade were routine preoperative imaging and device check requests. The upper extremity was the body region with the highest risk of poor RI-RADS grade. Requesting specialties with a high risk of poor RI-RADS grade were cardiovascular surgery, intensive care medicine, and orthopedics. The analysis of the interobserver agreement revealed substantial agreement for the RI-RADS grade.ConclusionThe majority of radiology exam requests were inadequate according to RI-RADS, especially those for routine imaging. RI-RADS demonstrated substantial reliability, suggesting that it can be satisfactorily employed in clinical settings.Critical relevant statementThe implementation of RI-RADS can provide a framework for standardizing radiology requests, thereby enabling quality assurance and promoting a culture of quality improvement.Key PointsRI-RADS aims to grade the completeness of radiology requests.Over half of the imaging requests were RI-RADS D grade; RI-RADS demonstrated substantial reliability.Most radiology requests were inadequate and RI-RADS could classify them in clinical practice.Graphical

Advanced Imaging Modalities in Cardiotoxicity: The Roles of Cardiac CT, MRI, and PET in Cardio-oncology

Advanced Imaging Modalities in Cardiotoxicity: The Roles of Cardiac CT, MRI, and PET in Cardio-oncology

Emerging Radiopharmaceuticals in Pet Imaging for Mesothelioma: A Review of [18F]FDG Alternatives.

Mesothelioma is a malignant tumor associated primarily with asbestos exposure, characterized by an aggressive nature and poor prognosis. Accurate diagnosis, staging, and monitoring of therapeutic response are crucial for effective patient management. Along with a computed tomography (CT) scan, fluorodeoxyglucose labeled with fluorine-18 ([18F]FDG) positron emission tomography (PET) is commonly used in mesothelioma evaluation. However, it has some limitations, including lower sensitivity after pleurodesis and poor accuracy for involved lymph node evaluation. Thus, there is the need to explore other agents. The aim of the present review is to analyze the current literature on the use of alternative radiopharmaceuticals for PET imaging in patients with mesothelioma. A comprehensive search of scientific databases (PubMed, Scopus, and Web of Science) for studies published in the last decade was performed by using the following keywords: "mesothelioma" AND "PET" AND "PET/CT" "radiopharmaceuticals", "[18F]FDG alternatives". Articles focused solely on [18F]FDG, non-English publications or preclinical studies, reviews, meeting abstracts, letters to the editors, and editorials were excluded. A qualitative assessment was made by using the Critical Appraisal Skills Programme (CASP) checklist for diagnostic test studies, when applicable. In total, 14 papers were selected; in seven articles more than five patients were enrolled, while the other seven were only clinical cases (enrolling up to two subjects). [18F]/gallium-68 ([68Ga])-labeled fibroblast activation protein inhibitor (FAPI) compounds, [18F]Fluorothymidine ([18F]FLT), methionine labeled with carbon-11 ([11C]MET), and fluoromisonidazole labeled with fluorine-18 ([18F]FMISO) PET/CT were the alternative agents used most often. In 12 articles, [18F]FDG PET/CT was used as a comparator imaging modality. Detection rate of [18F]FDG was similar to the other radiopharmaceuticals ([68Ga]/[18F]-labeled FAPI compounds, [18F]FLT, [18F]FMISO, [11C]MET, and [68Ga]-Pentaxifor), although radiolabeled FAPI seems to exhibit a higher diagnostic performance. [18F]FDG is still a valuable agent in patients with mesothelioma. However, radiolabeled FAPI appears to be promising and its theranostic properties should therefore be further assessed.

Deep learning-based temporal deconvolution for photon time-of-flight distribution retrieval.

The acquisition of the time of flight (ToF) of photons has found numerous applications in the biomedical field. Over the last decades, a few strategies have been proposed to deconvolve the temporal instrument response function (IRF) that distorts the experimental time-resolved data. However, these methods require burdensome computational strategies and regularization terms to mitigate noise contributions. Herein, we propose a deep learning model specifically to perform the deconvolution task in fluorescence lifetime imaging (FLI). The model is trained and validated with representative simulated FLI data with the goal of retrieving the true photon ToF distribution. Its performance and robustness are validated with well-controlled in vitro experiments using three time-resolved imaging modalities with markedly different temporal IRFs. The model aptitude is further established with in vivo preclinical investigation. Overall, these in vitro and in vivo validations demonstrate the flexibility and accuracy of deep learning model-based deconvolution in time-resolved FLI and diffuse optical imaging.

Olfactory neuroblastoma

Originating from the olfactory neuroepithelium, olfactory neuroblastoma is a rare malignant tumor of the nasal cavity that typically affects adults between the ages of 35 and 70. Clinical presentation predominantly consists of nonspecific symptoms such as nasal obstruction, nasal drainage or epistaxis, thus illustrating the need for a thorough diagnostic workup. In addition to a complete head and neck examination, rigid nasal endoscopy, biopsy and imaging are necessary to establish a definitive diagnosis as well as plan for treatment. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary imaging modalities utilized to assess for bony invasion and soft tissue involvement, respectively. Hyams grading system provides a histologic assessment of disease severity while various staging systems correlate severity of disease to anatomic location/progression. Treatment relies on both surgical intervention and radiation. In addition, ongoing research trials are investigating therapeutic targets. Given the risk of recurrence, extended post-treatment surveillance remains necessary.

Improved radiological imaging of congenital aural atresia using flat-panel volume CT.

Precise preoperative radiological evaluation of aural atresia is of utmost importance for surgical planning. Until now, multislice computed tomography (MSCT) has been used but it cannot adequately visualize small structures such as the stapes. Flat-panel volume CT (fpVCT) with its secondary reconstructions (fpVCTSECO) offers ahigh-resolution visualization of the middle ear. New otosurgical planning software also enables detailed 3D reconstruction of the middle ear anatomy. Evaluation of the use of fpVCTSECO in combination with an otosurgical planning software for amore accurate diagnosis and treatment of congenital aural atresia. Sevenpatients with congenital aural atresia underwent preoperative MSCT (600 µm slice thickness) and corresponding fpVCT (466 µm slice thickness). In addition, fpVCTSECO (99 µm slice thickness) were reconstructed. The Jahrsdoerfer and Siegert grading scores were determined and their applicability in the abovementioned imaging modalities was evaluated. In addition, the malleus incus complex was analyzed in 3D rendering. Imaging with fpVCTSECO enabled reliable visualization of the abnormalities, in particular the ossicular chain. Asignificant difference in the Siegert grading score was found. In addition, the malleus-incus complex could be visualized better in 3D. The introduction of new imaging techniques and surgical planning techniques into the diagnostic concept of aural atresia facilitates the identification of malformed anatomy and enables systematic analysis. This combination can also help to more accurately classify the pathology and thus increase the safety and success of the surgical procedure.

Diagnostic performance of multishot echo-planar imaging (RESOLVE) and non-echo-planar imaging (HASTE) diffusion-weighted imaging in cholesteatoma with an emphasis on signal intensity ratio measurement

To evaluate the diagnostic efficacy of multishot echo-planar imaging (EPI) [RESOLVE (RS)] and non-EPI (HASTE) diffusion-weighted imaging (DWI) in detecting cholesteatoma (CHO), and to explore the role of signal intensity (SI) ratio measurements in addressing diagnostic challenges. We analyzed RS-EPI and non-EPI DWI images from 154 patients who had undergone microscopic middle ear surgery, with pathological confirmation of their diagnoses. Two radiologists, referred to as Reader A and Reader B, independently reviewed the images without prior knowledge of the outcomes. Their evaluation focused on lesion location, T1-weighted (T1W) signal characteristics, and contrast enhancement in temporal bone magnetic resonance imaging. Key parameters included lesion hyperintensity, size, SI, SI ratio, and susceptibility artifact scores across both imaging modalities. Of the patients, 62.3% (96/154) were diagnosed with CHO, whereas 37.7% (58/154) were found to have non-CHO conditions. In RS-EPI DWI, Reader A achieved 89.6% sensitivity, 79.3% specificity, 87.8% positive predictive value (PPV), and 82.1% negative predictive value (NPV). Non-EPI DWI presented similar results with sensitivities of 89.6%, specificities of 86.2%, PPVs of 91.5%, and NPVs of 83.3%. Reader B’s results for RS-EPI DWI were 82.3% sensitivity, 84.5% specificity, 89.8% PPV, and 74.2% NPV, whereas, for non-EPI DWI, they were 86.5% sensitivity, 89.7% specificity, 93.3% PPV, and 80% NPV. The interobserver agreement was excellent (RS-EPI, κ: 0.84; non-EPI, κ: 0.91). The SI ratio measurements were consistently higher in non-EPI DWI (Reader A: 2.51, Reader B: 2.46) for the CHO group compared with RS-EPI. The SI ratio cut-off (>1.98) effectively differentiated hyperintense lesions between CHO and non-CHO groups, demonstrating 82.9% sensitivity and 100% specificity, with an area under the curve of 0.901 (95% confidence interval: 0.815–0.956; P < 0.001). Susceptibility artifact scores averaged 1.18 ± 0.7 (Reader A) and 1.04 ± 0.41 (Reader B) in RS-EPI, with non-EPI DWI recording a mean score of 0. Both RS-EPI and non-EPI DWI exhibited high diagnostic accuracy for CHO. While RS-EPI DWI cannot replace non-EPI DWI, their combined use improves sensitivity. SI ratio measurement in non-EPI DWI was particularly beneficial in complex diagnostic scenarios. This study refines CHO diagnostic protocols by showcasing the diagnostic capabilities of both RS-EPI and non-EPI DWI and highlighting the utility of SI measurements as a diagnostic tool. These findings may reduce false positives and aid in more accurate treatment planning, offering substantial insights for clinicians in managing CHO.

Paraganglioma With Intracranial Invasion Demonstrated on 68Ga-DOTATATE PET/CT.

68Ga-DOTATATE PET/CT demonstrates superior sensitivity compared with other cross-sectional and functional imaging techniques in detecting head and neck paragangliomas. It is the primary recommended imaging modality for the evaluation of head and neck paragangliomas, especially in patients suspected of having locally aggressive, multifocal, or metastatic disease, as well as those being considered for targeted peptide-receptor therapy. Herein, we demonstrate the 68Ga-DOTATATE PET/CT findings of a skull base paraganglioma with extensive local invasion and intracranial extension.