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High-Definition Optical Coherence Tomography in the Diagnosis of Basal Cell Carcinoma Evaluated by an Experienced Versus Inexperienced Investigator
摘要： Background: Histopathology is the gold standard in the diagnosis of basal cell carcinoma (BCC) but biopsies are invasive and often not the preferred diagnostic method for patients. In this context, non-invasive diagnostic imaging tools such as high definition optical coherence tomography (HD-OCT) have shown promising results in diagnosing BCC in real time, atraumatically and repeatedly. Objective: To evaluate the sensitivity and specificity of HD-OCT in the diagnosis of BCC by an experienced versus an inexperienced investigator and describe typical features in common differential diagnosis of BCC. Patients and methods: Forty three patients with clinical suspicion for BCC were included. The HD-OCT images were evaluated in a blinded manner by an experienced and inexperienced investigator. The results were compared to the histopathological diagnosis. Results: Histopathology revealed 22 BCC, 10 fibrous papules of the face, 5 actinic keratoses, 3 intradermal nevi, 2 squamous cell carcinomas and 1 sebaceous hyperplasia. The sensitivity and specificity in diagnosing BCCs correctly by HD-OCT in the experienced investigator was 86.4% and 90.5%, respectively. In the inexperienced investigator the sensitivity and the specificity was 77.3% and 81.0%, respectively. There was a good inter-observer agreement found between experienced and inexperienced investigators. Conclusion: HD-OCT can be used as auxiliary diagnostic tool in the evaluation and treatment of BCC even by inexperienced investigators.
关键词： Differential,Basal cell carcinoma,Optical coherence tomography,Diagnosis
更新于2025-09-23 15:23:52
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[SPIE Image Processing - Houston, United States (2018.2.10-2018.2.15)] Medical Imaging 2018: Image Processing - Deep learning for biomarker regression: application to osteoporosis and emphysema on chest CT scans
摘要： Introduction: Biomarker computation using deep-learning often relies on a two-step process, where the deep learning algorithm segments the region of interest and then the biomarker is measured. We propose an alternative paradigm, where the biomarker is estimated directly using a regression network. We showcase this image-to-biomarker paradigm using two biomarkers: the estimation of bone mineral density (BMD) and the estimation of lung percentage of emphysema from CT scans. Materials and methods: We use a large database of 9,925 CT scans to train, validate and test the network for which reference standard BMD and percentage emphysema have been already computed. First, the 3D dataset is reduced to a set of canonical 2D slices where the organ of interest is visible (either spine for BMD or lungs for emphysema). This data reduction is performed using an automatic object detector. Second, The regression neural network is composed of three convolutional layers, followed by a fully connected and an output layer. The network is optimized using a momentum optimizer with an exponential decay rate, using the root mean squared error as cost function. Results: The Pearson correlation coefficients obtained against the reference standards are r = 0.940 (p < 0.00001) and r = 0.976 (p < 0.00001) for BMD and percentage emphysema respectively. Conclusions: The deep-learning regression architecture can learn biomarkers from images directly, without indicating the structures of interest. This approach simplifies the development of biomarker extraction algorithms. The proposed data reduction based on object detectors conveys enough information to compute the biomarkers of interest.
关键词： regression,deep learning,bone mineral density,computed tomography,emphysema
更新于2025-09-23 15:23:52
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Effect of Object Position in Cone Beam Computed Tomography Field of View for Detection of Root Fractures in Teeth with Intra-Canal Posts
摘要： Background: Vertical root fracture (VRF) is a common problem in endodontically treated teeth. Due to its poor prognosis, a reliable technique must be used to make an accurate diagnosis. Cone beam computed tomography (CBCT) has been recently introduced for maxillofacial imaging. Despite the high diagnostic value of this method, metal artifacts resulting from intra-canal posts still make the detection of VRFs challenging. Objectives: This study aimed to assess the effect of object position in the field of view (FOV) of CBCT on detection of VRFs in teeth with intra-canal posts. Materials and Methods: The crowns of 60 extracted premolar teeth were cut at the level of cementoenamel junction (CEJ). Root canals were filled with gutta-percha and filling of the coronal 2/3 of the root canals was subsequently removed to fabricate intra-canal cast posts. The teeth were randomly divided into two groups of 30. Fracture was induced in group one using an Instron machine. Group two was considered as the control group with no fracture. All teeth were then randomly positioned and scanned in five different positions starting at the center of the FOV as well as right, left anterior and posterior relative to the center (3, 9, 12, and 6 O’clock) via the New Tom VGI CBCT unit. Two observers evaluated images for VRFs. Sensitivity and specificity of fracture diagnosis in each position was calculated in comparison with the gold standard. Wilcoxon test was used for data analysis. Results: Considering deterministic and probabilistic diagnostic parameters, probabilistic sensitivity was similar in all positions; but probabilistic specificity of the center position (65.1%) was significantly higher than that of 6 and 12 O’clock positions. Considering the deterministic diagnostic parameters, the overall sensitivity and specificity values decreased in all positions in FOV, but sensitivity of the center position of FOV was significantly higher than that of other positions; specificity was significantly higher at the 3 O’clock position (58.5%). Conclusion: Concerning the positions in FOV, the center position is suitable for detection of VRF in teeth with intra-canal posts due to significantly higher sensitivity at this position. The 3 O’clock position would be suitable for assessment of intact teeth without fractures due to significantly higher specificity at this position.
关键词： Post and Core Technique,Position,Tooth Fracture,Cone-Beam Computed Tomography
更新于2025-09-23 15:23:52
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Development of Animation Projector System and Usefulness in Pediatric Head CT; 小児頭部 CT のためのアニメーション投影システムの考案;
摘要： The restlessness of young children often causes motion artifacts on CT images. We devised a new animation projector system (CT Theater) that enables a child to view an animation during a pediatric head CT examination. The purpose of this study is to assess the usefulness on a children of a video viewed during a head CT scan. Children of 3–10 years old who underwent head CT (SOMATOM Definition Flash, SOMATOM Force; Siemens) were analyzed for a period from 6 months before, to 6 months after, introduction of the projector system (before: n=46, after: n=29). Mobile projector (MP-CL1; Sony) connected with tablet device (iPad; Apple) was put on the CT table near the child’s head. An animation was projected onto the child’s line of sight inside the gantry. The animation is projected onto the line of sight of the child such that the projector moves with the child on the table. The number of requests for use made by children was 28/29 (96.6%). The presence of images without motion artifacts decreased significantly after introduction (before/after introduction: 84.8% vs 100%, p=0.03). The overall examination success rate tended to increase after introduction (84.8% vs 92.9%, p=0.26). The overall examination time was significantly reduced (92.4±42.4 s vs 65.1±47.3 s, p<0.001). We developed an animation projector system that shortened examination time and decreased motion artifacts in pediatric head CT.
关键词： motion artifact,pediatric,computed tomography,distraction,mobile projector
更新于2025-09-23 15:23:52
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Influence of Heart Rate and Innovative Motion-Correction Algorithm on Coronary Artery Image Quality and Measurement Accuracy Using 256-Detector Row Computed Tomography Scanner: Phantom Study
摘要： Objective: To investigate the efficacy of motion-correction algorithm (MCA) in improving coronary artery image quality and measurement accuracy using an anthropomorphic dynamic heart phantom and 256-detector row computed tomography (CT) scanner. Materials and Methods: An anthropomorphic dynamic heart phantom was scanned under a static condition and under heart rate (HR) simulation of 50–120 beats per minute (bpm), and the obtained images were reconstructed using conventional algorithm (CA) and MCA. We compared the subjective image quality of coronary arteries using a four-point scale (1, excellent; 2, good; 3, fair; 4, poor) and measurement accuracy using measurement errors of the minimal luminal diameter (MLD) and minimal luminal area (MLA). Results: Compared with CA, MCA significantly improved the subjective image quality at HRs of 110 bpm (1.3 ± 0.3 vs. 1.9 ± 0.8, p = 0.003) and 120 bpm (1.7 ± 0.7 vs. 2.3 ± 0.6, p = 0.006). The measurement error of MLD significantly decreased on using MCA at 110 bpm (11.7 ± 5.9% vs. 18.4 ± 9.4%, p = 0.013) and 120 bpm (10.0 ± 7.3% vs. 25.0 ± 16.5%, p = 0.013). The measurement error of the MLA was also reduced using MCA at 110 bpm (19.2 ± 28.1% vs. 26.4 ± 21.6%, p = 0.028) and 120 bpm (17.9 ± 17.7% vs. 34.8 ± 19.6%, p = 0.018). Conclusion: Motion-correction algorithm can improve the coronary artery image quality and measurement accuracy at a high HR using an anthropomorphic dynamic heart phantom and 256-detector row CT scanner.
关键词： Heart rate,Tomography,X-ray computed,Coronary vessels,Phantoms,Imaging,Motion-correction algorithm
更新于2025-09-23 15:23:52
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A Nanoprobe for Diagnosing and Mapping Lymphatic Metastasis of Tumor Using 3D Multispectral Optoacoustic Tomography Owing to Aggregation/Deaggregation Induced Spectral Change
摘要： Lymphatic metastasis of tumor is one of leading causes of cancer-related death, and diagnosing lymphatic metastasis is of significance in terms of optimal disease management and possible better outcomes for patients. Herein a turn-on optoacoustic nanoprobe is reported for noninvasively diagnosing and locating lymphatic metastasis in vivo. A positively charged tricyanofuran-containing polyene chromophore (TCHM) with high extinction coefficient is designed, synthesized, and allowed to form the nanoprobe with a negatively charged hyaluronan. The TCHMs take an aggregated state within the nanoprobe and exhibit weak absorption at 882 nm, the overexpressed hyaluronidase in cancer cells specifically degrades hyaluronan into small fragments and disaggregates TCHMs, thereby greatly enhancing the absorption at 882 nm and generating prominent optoacoustic signals. For multispectral optoacoustic tomography (MSOT) imaging in vivo, mice models with subcutaneous tumor and orthotopic bladder tumor are imaged first to demonstrate the nanoprobe’s capability for detecting HAase-overexpressing tumors. A mouse model of lymphatic metastasis of tumor is then established and the lymphatic metastasis is successfully imaged and tracked optoacoustically. The imaging results were verified using multiple biochemical assays. Moreover, 3D MSOT renderings are obtained for precisely locating and tracking the metastasis of tumor in lymphatic system in a spatiotemporal manner.
关键词： lymphatic metastasis,imaging,multispectral,nanoprobe,3D,optoacoustic tomography,aggregation
更新于2025-09-23 15:23:52
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Evaluation of patient effective dose in a PET/CT test
摘要： The positron emission tomography (PET)/computed tomography (CT) technique generates high doses in patients because two radiodiagnostic modalities are used in a single examination. In this study, the absorbed and effective doses generated by CT scans and by the incorporation of radiopharmaceutical solution were evaluated in 19 organs. It was found that 78.2% of the effective dose in PET/CT examinations comes from the CT scan. With an activity of 3.33 MBq/kg, 18F-FDG contributes 21.8% of the final effective dose.
关键词： Patient dosimetry,PET/CT,Computed tomography
更新于2025-09-23 15:23:52
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Choroidal thickness in healthy eyes using enhanced depth imaging optical coherence tomography and comparison with cases of retinitis pigmentosa
摘要： Introduction. — The goal of this study was to measure by spectral domain optical coherence tomography (SD-OCT) with EDI the choroidal thickness in healthy subjects and to compare these parameters with those of patients with retinitis pigmentosa (RP). Methods. — Data were obtained from 60 healthy patients without history or family history of retinal or choroidal disease or glaucoma. A case-control study was also conducted on 40 eyes of 20 patients with RP and 40 eyes of 20 healthy refraction- and age-matched controls, selected from among the 60 healthy patients. OCT was used with the EDI protocol. The primary outcome measure was choroidal thickness. Results. — Among healthy patients, the overall choroidal thickness was 287.7 μm. Mean choroidal thickness was lower on the nasal side (236.6 μm from the fovea) compared with the temporal side (262.3 μm, P = 0.002). It also varied according to age, being highest among 20—29-year-old patients and decreasing thereafter with increasing age. Choroidal thickness was significantly higher in healthy patients than in RP patients, regardless of the location (P < 0.001). Conclusion. — This observational study confirms that choroidal thickness varies with age and location. It decreases in subjects with RP and is related to worsening of retinal damage, independently of age-related thinning. Further studies are needed to understand whether choroidal vascular alteration is a cause or a consequence of the degenerative pathology.
关键词： Photoreceptor degeneration,Choroidal thickness,Case-control study,Retinitis pigmentosa,Enhanced depth imaging optical coherence tomography
更新于2025-09-23 15:23:52
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A geometric partitioning method for distributed tomographic reconstruction
摘要： Tomography is a powerful technique for 3D imaging of the interior of an object. With the growing sizes of typical tomographic datasets, the computational requirements for algorithms in tomography are rapidly increasing. Parallel and distributed-memory methods for tomographic reconstruction are therefore becoming increasingly common. An under-exposed aspect is the effect of the data distribution on the performance of distributed-memory reconstruction algorithms. In this work, we introduce a geometric partitioning method, which takes into account the acquisition geometry and aims to minimize the necessary communication between nodes for distributed-memory forward projection and backprojection operations. These operations are crucial subroutines for an important class of reconstruction methods. We show that the choice of data distribution has a significant impact on the runtime of these methods. With our novel partitioning method we reduce the communication volume drastically compared to straightforward distributions, by up to 90% for a number of cases, and furthermore we guarantee a specified load balance.
关键词： sparse matrix,tomography,matrix partitioning,parallel computing
更新于2025-09-23 15:23:52
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Deep structure tensor graph search framework for automated extraction and characterization of retinal layers and fluid pathology in retinal SD-OCT scans
摘要： Maculopathy is a group of retinal disorders that affect macula and cause severe visual impairment if not treated in time. Many computer-aided diagnostic methods have been proposed over the past that automatically detect macular diseases. However, to our best knowledge, no literature is available that provides an end-to-end solution for analyzing healthy and diseased macular pathology. This paper proposes a vendor-independent deep convolutional neural network and structure tensor graph search-based segmentation framework (CNN-STGS) for the extraction and characterization of retinal layers and fluid pathology, along with 3-D retinal profiling. CNN-STGS works by first extracting nine layers from an optical coherence tomography (OCT) scan. Afterward, the extracted layers, combined with a deep CNN model, are used to automatically segment cyst and serous pathology, followed by the autonomous 3-D retinal profiling. CNN-STGS has been validated on publicly available Duke datasets (containing a cumulative of 42,281 scans from 439 subjects) and Armed Forces Institute of Ophthalmology dataset (containing 4,260 OCT scans of 51 subjects), which are acquired through different OCT machinery. The performance of the CNN-STGS framework is validated through the marked annotations, and it significantly outperforms the existing solutions in various metrics. The proposed CNN-STGS framework achieved a mean Dice coefficient of 0.906 for segmenting retinal fluids, along with an accuracy of 98.75% for characterizing cyst and serous fluid from diseased retinal OCT scans.
关键词： convolutional neural network (CNN),Optical coherence tomography (OCT),maculopathy,ophthalmology,graph search
更新于2025-09-23 15:23:52