3D Computed Tomography Research Articles

A new weighting scheme for arc based circle cone-beam CT reconstruction.

In this paper, we present an arc based fan-beam computed tomography (CT) reconstruction algorithm by applying Katsevich's helical CT image reconstruction formula to 2D fan-beam CT scanning data. Specifically, we propose a new weighting function to deal with the redundant data. Our weighting function ϖ(x_,λ) is an average of two characteristic functions, where each characteristic function indicates whether the projection data of the scanning angle contributes to the intensity of the pixel x_. In fact, for every pixel x_, our method uses the projection data of two scanning angle intervals to reconstruct its intensity, where one interval contains the starting angle and another contains the end angle. Each interval corresponds to a characteristic function. By extending the fan-beam algorithm to the circle cone-beam geometry, we also obtain a new circle cone-beam CT reconstruction algorithm. To verify the effectiveness of our method, the simulated experiments are performed for 2D fan-beam geometry with straight line detectors and 3D circle cone-beam geometry with flat-plan detectors, where the simulated sinograms are generated by the open-source software "ASTRA toolbox." We compare our method with the other existing algorithms. Our experimental results show that our new method yields the lowest root-mean-square-error (RMSE) and the highest structural-similarity (SSIM) for both reconstructed 2D and 3D fan-beam CT images.

Dynamic three-dimensional computed tomographic imaging facilitates evaluation of the equine cervical articular process joint in motion.

Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. Descriptive cadaver imaging. Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck specimens and perform dynamic 2D and 3D CT imaging. Images were obtained with a 320-detector-row CT scanner with a 160mm wide-area (2D) solid-state detector design that allows image acquisition of a volumetric axial length of 160mm without moving the CT couch. Dynamic videos were acquired and divided into four phases of movement. Three blinded observers used a subjective scale of 1 (excellent) to 4 (poor) to grade the overall image quality in each phases of motion cycle. With an overall median score of 1 the image quality, a significantly lower score was observed in the dynamic 3D videos over the four phases by the three observers compared with the 2D videos for both flexion (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P=.007) and extension movement (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P=.008). Median Translational displacement of the APJ surface was significantly greater in flexion than in extension movement (P=.002). The small number of specimens included. Excision of spines and removal of musculature. The study is a first step in the investigation of the potential of dynamic 3D CT in veterinary medicine, a technique that has only begun to be explored and leaves much room for refinement prior to its introduction in routine practice. CT with a detector coverage of 16cm and a rotation speed of 0.32seconds provides high-quality images of moving objects and gives new insight into the movement pattern of equine cervical APJs.

Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement.

The measurements of the right ventricle (RV) and pulmonary artery (PA), for selecting the optimal prosthesis size for transcatheter pulmonary valve replacement (TPVR), vary considerably. Three-dimensional (3D) computed tomography (CT) imaging for device size prediction is insufficient to assess the displacement of the right ventricular outflow tract (RVOT) and PA, which could increase the risk of stent misplacement and paravalvular leak. The aim of this study is to provide a dynamic model to visualize and quantify the anatomy of the RVOT to PA over the entire cardiac cycle by four-dimensional (4D) cardiac CT reconstruction to obtain an accurate quantitative evaluation of the required valve size. In this pilot study, cardiac CT from sheep J was chosen to illustrate the procedures. 3D cardiac CT was imported into 3D reconstruction software to build a 4D sequence which was divided into eleven frames over the cardiac cycle to visualize the deformation of the heart. Diameter, cross-sectional area, and circumference of five imaging planes at the main PA, sinotubular junction, sinus, basal plane of the pulmonary valve (BPV), and RVOT were measured at each frame in 4D straightened models prior to valve implantation to predict the valve size. Meanwhile, dynamic changes in the RV volume were also measured to evaluate right ventricular ejection fraction (RVEF). 3D measurements at the end of the diastole were obtained for comparison with the 4D measurements. In sheep J, 4D CT measurements from the straightened model resulted in the same choice of valve size for TPVR (30 mm) as 3D measurements. The RVEF of sheep J from pre-CT was 62.1 %. In contrast with 3D CT, the straightened 4D reconstruction model not only enabled accurate prediction for valve size selection for TPVR but also provided an ideal virtual reality, thus presenting a promising method for TPVR and the innovation of TPVR devices.

High-Contrast Lumbar Spinal Bone Imaging Using a 3D Slab-Selective UTE Sequence.

Ultra-short echo time (UTE) MRI with post-processing is a promising technique in bone imaging that produces a similar contrast to computed tomography (CT). Here, we propose a 3D slab-selective ultrashort echo time (UTE) sequence together with image post-processing to image bone structures in the lumbar spine. We also explore the intermodality agreement between the UTE and CT images. The lumbar spines of two healthy volunteers were imaged with 3D UTE using five different resolutions to determine the best imaging protocol. Then, four patients with low back pain were imaged with both the 3D UTE sequence and CT to investigate agreement between the imaging methods. Two other patients with low back pain were then imaged with the 3D UTE sequence and clinical conventional T1-weighted and T2-weighted fast spin-echo (FSE) MRI sequences for qualitative comparison. The 3D UTE sequence together with post-processing showed high contrast images of bone and high intermodality agreement with CT images. In conclusion, post-processed slab-selective UTE imaging is a feasible approach for highlighting bone structures in the lumbar spine and demonstrates significant anatomical correlation with CT images.

A two-stage deep generative adversarial quality enhancement network for real-world 3D CT images

High-quality (HQ) three-dimensional (3D) images are the premise of analyzing the properties of porous media such as rocks. X-ray computed tomography (CT) is one of the most widely used imaging tools to capture the 3D images of rock samples. Nevertheless, the quality (e.g., resolution, sharpness, and the signal-to-noise ratio) of the collected rock CT images may not meet the needs of practical applications in some cases due to the limitations of imaging systems, leading to inaccurate results of property analysis. In this paper, aiming at improving the quality of rock CT images as well as the accuracy of property analysis, we develop a two-stage deep generative adversarial quality enhancement network for real-world 3D CT images, namely the CTQENet. More specifically, the proposed CTQENet consists of a two-dimensional (2D) reconstruction module (2DRM) and a 3D fusion module (3DFM), which enhance the quality of 3D CT images from the perspective of 2D slices and 3D volumes, respectively. In order to remove artifacts and enhance the resolution of real-world CT images, the 2DRM takes the cycle-consistent generative adversarial network as the backbone to learn the mapping from low-quality (LQ) 2D slices to HQ ones without one-to-one paired training data. Then, the 3D CT volumes stacked by the reconstructed HQ slices along the x/y/z-axis are adaptively fused in the generative adversarial network-based 3DFM, to achieve more reliable 3D morphological structures. Qualitative and quantitative comparisons show the effectiveness of the proposed CTQENet for real-world 3D CT images of rock samples. In particular, the reconstructed HQ 3D CT images by CTQENet show similar morphological characteristics and statistical properties with HQ targets. This study makes it possible to obtain higher quality 3D CT images that partly exceed the limitations of CT imaging systems for better visual experience and more accurate property analysis.

Importance of four-dimensional computed tomography simulation in locally advanced lung cancer radiotherapy: Impact on reducing planning target volume

Background/Aim. Four-dimensional (4D) computed tomography (CT) simulation is a useful tool for motion assessment in lung cancer radiotherapy. Conventional three-dimensional (3D) free-breathing (FB) simulation is static, with limited motion information on respiratory movements that can produce inaccuracies in the delineation process and radiotherapy planning. The aim of this study was to compare clinically significant differences between the target volumes defined on 3D CT vs. 4D CT simulation and the potential impact on the planning target volume (PTV), bearing in mind that a reduced PTV with precise coverage of the primary tumor is extremely important. In addition, quantification of movements of the primary tumor (gross tumor volume ? GTV) was performed during 4D CT simulation on three axes: Z-superoinferior (SI), X-mediolateral (ML), and Y-anteroposterior (AP). Methods. This retrospective study evaluated 20 lung cancer patients who underwent CT simulation for radical radiotherapy treatment. FB 3D CT and 4D CT simulations were acquired for each patient in accordance with our institutional protocol. A volumetric comparison of radiation volumes defined on 3D CT vs. 4D CT simulation was done on the following: GTV 3D vs. internal GTV (IGTV) 4D and PTV 3D vs. internal PTV (IPTV) 4D. The comparison of GTV movement in the FB phase GTV (GTV FB), phase 0 (GTV 0), phase 50 (GTV 50), and phase maximum intensity projection (GTV MIP) was made with GTV FB as the basic value. The evaluation was made on all three axes. Results. The comparison of volumetric values between GTV 3D vs. IGTV 4D was 63.15 cm3 vs. 85.51 cm3 (p < 0.001), respectively. IGTV 4D was significantly larger than GTV 3D (p < 0.001). The mean value of equivalent spherical diameter (ESD) for PTV 3D vs. IPTV 4D was 8.44 cm vs. 7.82 cm (p < 0.001), respectively, and the mean value volume PTV 3D vs. IPTV 4D was 352.70 cm3 vs. 272.78 cm3 (p < 0.001), respectively. PTV 3D was significantly larger than IPTV 4D (p < 0.001). A statistically significant difference (p < 0.05) was identified in the deviation related to the Z-axis between the upper and lower lobe. Conclusion. 4D CT simulation-based delineation can reduce PTV compared to 3D simulation-based radiation therapy; therefore, it is a prerequisite for high-quality and precise radiation therapy treatment.

Study on Dangerous Acupuncture Needling Depth at Yamen (GV15) for Atlantoaxial Dislocation based on MRI and CT

Background: The depth of acupuncture at GV15 significantly changes with atlantoaxial dislocation (AAD). Magnetic resonance imaging (MRI) and computed tomography (CT) are the current methods for assessing acupuncture depth. However, the acupuncture depth in patients with AAD and the best evaluation method for acupuncture have not been thoroughly studied. Objectives: Based on MRI and 3D CT imaging measurements, dangerous needling depths for perpendicular acupuncture and oblique acupuncture in patients with AAD and normal anatomy were obtained. The application value of MRI and 3D CT in evaluating acupuncture depth is discussed. Methods: From January 2018 to December 2021, patients with AAD (120 patients) and control patients without AAD (124 patients) diagnosed and treated at the Upper Cervical Spine Research Center of the China-Japan Friendship Hospital were selected. All patients were enrolled. Both groups included patients with normal body types (BMI 18.5-23.9). The two groups of patients underwent plain cervical MRI scans and three-dimensional plain CT scans, and the dangerous needling depth of the perpendicular spur and the oblique spur were measured on sagittal images. Results: No significant differences were observed between the two measurements (MRI and CT) (P<0.05). The dangerous needling depths in the AAD group were as follows: male straight stab: 45.33±5.17 mm, male oblique stab: 48.58±4.41 mm, female straight thorn: 44.17±7.80 mm, and female oblique thorn: 47.49±7.32 mm. The dangerous needling depths for the control group were as follows: male straight thorn: 47.72±5.06 mm, male oblique thorn: 42.69±5.53 mm, female straight thorn: 44.63±5.85 mm, and female oblique thorn: 39.88 ± 6.18 mm. Conclusions: Acupuncture depth at the dumb point of the AAD changed significantly. The clinical acupuncture depth should not exceed this safe depth. Both CT and MRI can be used to assess dangerous needling depth at GV15.

Comparison of Plain Radiography with Spiral Computed Tomography and 3D Reformation in Tibial Plateau Fractures: A Cross-sectional Study

Introduction: Tibial plateau fractures may result in major disabilities if not diagnosed at the right time. Plain radiography is the first and foremost imaging modality of choice to evaluate trauma followed by Computed Tomography (CT). Aim: To evaluate tibial plateau fractures on CT and compare them with 3D reformations and plain radiography, and classify the fractures using Schatzker’s classification. Materials and Methods: The prospective cross-sectional study was conducted at a tertiary care centre in Bengaluru, Karnataka, India, between November 2016 to June 2018. The study sample comprised of 53 patients who presented with fracture of the tibial plateau. Demographic details and brief clinical history of the subjects were recorded. All patients underwent conventional radiography as well as CT of the knee, including three-Dimensional (3D) reconstruction. The region of interest was assessed for the presence, displacement, depression, extent and comminution of the fracture. Data was analysed using R version 4.0.3. Chi-square test was used to see the association between different variables. Cohen’s Kappa was employed to determine the agreement of plain radiograph and CT findings. Results: The mean age of patients was 44.01±13.23 years. The extent of the fracture line and communition of fracture were visible on all sections of CT for all samples, but 3D CT did not reveal the extent of the fracture line in 9.43% of the sample (p=0.003) and communition was visible only in 15.09% of the sample. On comparing the plain radiograph and CT findings for tibial plateau fractures, a close to perfect agreement in diagnosing the displacement of fracture (Cohen’s Kappa, 0.9618, p<0.001), followed by a fair agreement in diagnosing fracture communition (Cohen’s Kappa, 0.3748; p=0.0015) were noted. The positive predictive value of tibial plateau fracture detection rate by plain radiography and CT findings were 88.7% and 98.1%, respectively. These fractures assessed as per Schatzker’s classification revealed majority of the patients had bicondylar plateau with diaphyseal discontinuity 19 (35.85%) followed by bicondylar plateau 14 (26.42%). Conclusion: In this study, CT was observed to be an excellent modality for the evaluation of tibial plateau fractures including depression, displacement, comminution and extent of fractures when compared to plain radiography.

Three Dimensional Morphological Grading of the Ankylosed TMJ for Surgical Planning: A Retrospective Observational Study

Introduction: Temporomandibular Joint (TMJ) ankylosis remains an enigma in craniofacial surgery due to the challenges encountered while restoring mouth opening, facial form and airway to normalcy. Though TMJ ankylosis is a relatively simple diagnosis to make, the specific surgical plan depends on the nature and extent of the fusion of the mandible with the cranial base. Aim: To classify the pattern of bone deformity found in TMJ ankylosis using three Dimensional (3D) Computed Tomography (CT) imaging and its role in determining the type of procedures required for effective gap arthroplasty. Materials and Methods: The 3D CT reconstructed images of 66 consecutive patients having 82 ankylosed joints treated from January 2007 to December 2019 with a standardised protocol was evaluated retrospectively. A grading system was used with the following criteria: coronoid hyperplasia, sigmoid notch to skullbase fusion and loss of residual joint space. The gap arthroplasty required for each grade of ankylosis was also analysed. The complete data in the present study was tabulated in Microsoft excel sheet and frequency (n) analysis was done for all variables. Results: Out of 66 patients (82 ankylotic joints) 37 males and 29 females), age range 2.5 years to 51 years, average age 18.2 years) 27% of the total joints surveyed belonged to grade 1 type of ankylosis. None of these joints had complete bony fusion (absence of the radiolucent zone between the cranium and condyle). A 10% of the joints had moderate ankylosis (grade 2). None of them revealed complete bony fusion (absence of the radiolucent zone) or fusion of the sigmoid with the cranial base. Grade 3 ankylosis was the most widely seen pattern of ankylosis (63% of the present study subjects) and 92% had a history of childhood onset. A 90% of the joints in this group had ipsilateral coronoid hyperplasia. A 48% of the joints with severe ankylosis (grade 3) showed bony fusion with the cranial base, with loss or absence of the radiolucent zone {Fusion Line (FL)} between the cranial base and the condyle. Conclusion: The extent and severity of TMJ ankylosis needs to be ascertained prior to planning TM Joint ankylosis surgery. A 3D CT assessment and subsequent radiologic grading provides a reliable guide for ankylosis release.

NO SIGNIFICANT EFFECT OF 3D MODELLING ON SURGICAL PLANNING IN SPINAL DEFORMITIES.

ABSTRACTObjective:To evaluate the effect of 3d printed models on surgical pre-operative planning of complex spinal deformities.Methods:In our study, five orthopedic surgeons made surgical planning of 5 patients with severe spinal deformity in three conditions: X-ray with computer tomography (X-ray-CT), 3D-computed tomography (3dCT), and 3d printed spine models. Operation plans were examined according to the level and number of instrumentations, osteotomy level, and time required for decision-making.Results:X-ray-CT, 3dCT, and 3d modeling methods were compared, and no statistically significant difference was observed in the number of screws and osteotomy score to be used in operation. The time required for decision ranking is 3d Model, 3d CT, and Xray-CT.Conclusions:3d printed models do not influence the operative plan significantly; however, it reduces surgical planning time at pre-op duration, and those models gave some opportunities to practice with implants on a patient’s 3d spine model. Level of Evidence III; Diagnostic Studies - Investigating a Diagnostic Test .

Evaluation of dose–Volume-based image-guided high-dose-rate brachytherapy in carcinoma uterine cervix: A prospective study

Background: In recent few decades, the evolution in imaging technology, especially computed tomography (CT) and magnetic resonance imaging, results in widespread availability and its use in high-dose-rate (HDR) intracavitary brachytherapy (ICBT) applications. Aim: The present study was aimed to analyze the cumulative dose–volume histogram of the tumor and organs at risk (OARs) in three-dimensional (3D) CT image-based brachytherapy planning and clinical outcomes of the treated patients. Materials and Methods: This prospective observational study included 40 patients with carcinoma cervix. After external beam radiotherapy (EBRT), a dose of 6 Gy per fraction of HDR ICBT in four fractions with a total dose to point “A” approximately 80–85 Gy was given. For planning, the tumor volumes (high-risk clinical target volume [HR-CTV]) and volume of OARs (bladder, rectum, and sigmoid colon) were contoured on each CT slice. The dose–volume parameters, i.e., minimum dose received to 90% and 100% by HR-CTV volume (D90 and D100) for target and the maximum dose received by minimum volume of 2CC (D2CC) for OARs, were calculated and assessed for clinical response in patients. Results: The mean D2CC dose was 18.24 ± 0.93 Gy, 16.44 ± 1.11 Gy, and 16.37 ± 0.67 Gy for bladder, rectum, and sigmoid colon, respectively. The combined (EBRT and HDR ICBT) mean equieffective dose in 2 Gy per fraction (EQD2) dose for bladder was 76.71 ± 2.05 Gy, for rectum was 72.82 ± 2.58 Gy, and for sigmoid colon was 72.71 ± 1.41 Gy, and its comparison with baseline values showing P < 0.01 for bladder, rectum, and sigmoid colon was considered statistically significant. The mean EQD2 dose of HR-CTV D90 was 151 ± 27.3 Gy. Patients who had received HR-CTV D90 of >90 Gy compared with <90 Gy had exceptionally better local control and complete response. Conclusion: The present study suggested that CT is a favorable modality for treatment planning in cervical cancer with limited resources setup in terms of improved tumor coverage, lesser toxicity, confirmation of applicator placement, and accounting dose to OARs.

Three-dimensional muscle loss assessment: a novel computed tomography–based quantitative method to evaluate rotator cuff muscle fatty infiltration

Rotator cuff fatty infiltration (FI) is one of the most important parameters to predict the outcome of certain shoulder conditions. The primary objective of this study was to define a new computed tomography (CT)-based quantitative 3-dimensional (3D) measure of muscle loss (3DML) based on the rationale of the 2-dimensional (2D) qualitative Goutallier score. The secondary objective of this study was to compare this new measurement method to traditional 2D qualitative assessment of FI according to Goutallier etal and to a 3D quantitative measurement of fatty infiltration (3DFI). 102 CT scans from healthy shoulders (46) and shoulders with cuff tear arthropathy (21), irreparable rotator cuff tears (18), and primary osteoarthritis (17) were analyzed by 3 experienced shoulder surgeons for subjective grading of fatty infiltration according to Goutallier, and their rotator cuff muscles were manually segmented. Quantitative 3D measurements of fatty infiltration (3DFI) were completed. The volume of muscle fibers without intramuscular fat was then calculated for each rotator cuff muscle and normalized to the patient's scapular volume to account for the effect of body size (NVfibers). 3D muscle mass (3DMM) was calculated by dividing the NVfibers value of a given muscle by the mean expected volume in healthy shoulders. 3D muscle loss (3DML) was defined as 1 - (3DMM). The correlation between Goutallier grading, 3DFI, and 3DML was compared using a Spearman rank correlation. Interobserver reliability for the traditional 2D Goutallier grading was moderate for the infraspinatus (ISP, 0.42) and fair for the supraspinatus (SSP, 0.38), subscapularis (SSC, 0.27) and teres minor (TM, 0.27). 2D Goutallier grading was found to be significantly and highly correlated with 3DFI (SSP, 0.79; ISP, 0.83; SSC, 0.69; TM, 0.45) and 3DML (SSP, 0.87; ISP, 0.85; SSC, 0.69; TM, 0.46) for all 4 rotator cuff muscles (P < .0001). This correlation was significantly higher for 3DML than for the 3DFI for SSP only (P = .01). The mean values of 3DFI and 3DML were 0.9% and 5.3% for Goutallier 0, 2.9% and 25.6% for Goutallier 1, 11.4% and 49.5% for Goutallier 2, 20.7% and 59.7% for Goutallier 3, and 29.3% and 70.2% for Goutallier 4, respectively. The Goutallier score has been helping surgeons by using 2D CT scan slices. However, this grading is associated with suboptimal interobserver agreement. The new measures we propose provide a more consistent assessment that correlates well with Goutallier's principles. As 3DML measurements incorporate atrophy and fatty infiltration, they could become a very reliable index for assessing shoulder muscle function. Future algorithms capable of automatically calculating the 3DML of the cuff could help in the decision process for cuff repair and the choice of anatomic or reverse shoulder arthroplasty.

Uncertainty-guided graph attention network for parapneumonic effusion diagnosis

Parapneumonic effusion (PPE) is a common condition that causes death in patients hospitalized with pneumonia. Rapid distinction of complicated PPE (CPPE) from uncomplicated PPE (UPPE) in Computed Tomography (CT) scans is of great importance for the management and medical treatment of PPE. However, UPPE and CPPE display similar appearances in CT scans, and it is challenging to distinguish CPPE from UPPE via a single 2D CT image, whether attempted by a human expert, or by any of the existing disease classification approaches. 3D convolutional neural networks (CNNs) can utilize the entire 3D volume for classification: however, they typically suffer from the intrinsic defect of over-fitting. Therefore, it is important to develop a method that not only overcomes the heavy memory and computational requirements of 3D CNNs, but also leverages the 3D information. In this paper, we propose an uncertainty-guided graph attention network (UG-GAT) that can automatically extract and integrate information from all CT slices in a 3D volume for classification into UPPE, CPPE, and normal control cases. Specifically, we frame the distinction of different cases as a graph classification problem. Each individual is represented as a directed graph with a topological structure, where vertices represent the image features of slices, and edges encode the spatial relationship between them. To estimate the contribution of each slice, we first extract the slice representations with uncertainty, using a Bayesian CNN: we then make use of the uncertainty information to weight each slice during the graph prediction phase in order to enable more reliable decision-making. We construct a dataset consisting of 302 chest CT volumetric data from different subjects (99 UPPE, 99 CPPE and 104 normal control cases) in this study, and to the best of our knowledge, this is the first attempt to classify UPPE, CPPE and normal cases using a deep learning method. Extensive experiments show that our approach is lightweight in demands, and outperforms accepted state-of-the-art methods by a large margin. Code is available at https://github.com/iMED-Lab/UG-GAT.

Relevant Anatomical Details in Rats Regarding Otologic Research

The objective of the study was to provide a detailed anatomical description of the rat’s ear anatomy that will prove insightful to different experimental otologic surgical procedures regardless of scope. Three male Wistar rats were enrolled in the study. Candidates were screened for systemic and otologic pathology. External ear canal endoscopy was carried out with a 30˚ rigid endoscope through an image capture system. Middle ear anatomical elements were analyzed under stereomicroscopy. 3D computer tomography image reconstruction was realized with a micro-CT to describe the anatomy. Image data from all three rats were analyzed. Anatomical annotations and surgical exposure recommendations were added for key elements. The most relevant images from all three rats were selected for representation. Detailed visualization of the structural elements of the tympanic cavity were clearly visible: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane were all constant findings. We describe a step wise ventral surgical approach of the middle and inner ear for which we found that the clavotrapezius muscle was a reliable landmark. For the transtympanic approach the endoscopic transcanal access was an easy and reliable method for which a detailed anatomical representation was depicted. Further, anatomical similarities to humans were observed by stereomicroscopy and Micro-CT imaging reiterating that the rat model is suitable for otologic research. The endoscopic approach to the tympanic membrane is comfortable and less expensive than a microscope. The tendon of the clavotrapezius muscle can be a reliable landmark for discovering the tympanic bulla when considering a ventral approach. 3D Micro-CT reconstruction allows intact evaluation of the samples, simultaneously being a diagnostic and also a learning tool.

Potential therapeutic response in a severe case of autosomal dominant osteopetrosis type I

The low-density lipoprotein receptor-related protein 5 gene (LRP5), which encodes a coreceptor within the canonical Wnt signaling pathway, plays a crucial role in bone mass regulation and has been associated with several bone disorders. Autosomal dominant osteopetrosis type I (ADO type I, OMIM 607634) is a rare disease caused by heterozygous, gain-of-function mutations in LRP5. Here we describe a 44-year-old female who presented with thickened calvarium, elevated bone density, torus palatinus, mandibular exostoses, enlarged mandible, and disabling headaches and bone pain. Exome sequencing revealed a previously reported heterozygous missense variant in the LRP5 gene (p.A242T). Post-diagnosis cranial vault volume measurement by computed tomography 3D reconstruction demonstrated decreasing intracranial volume over time. Off-label use of leuprolide acetate was associated with apparent stabilization of skull mineralization. This report documents a severe example of ADO type I and provides anecdotal evidence of the utility of therapy in need of formal evaluation.

Prediction and verification of survival in patients with non-small-cell lung cancer based on an integrated radiomics nomogram

To develop and validate a nomogram to predict 1-, 2-, and 5-year survival in patients with non-small-cell lung cancer (NSCLC) by combining optimised radiomics features, clinicopathological factors, and conventional image features extracted from three-dimensional (3D) computed tomography (CT) images. A total of 172 patients with NSCLC were selected to construct the model, and 74 and 72 patients were selected for internal validation and external testing, respectively. A total of 828 radiomics features were extracted from each patient's 3D CT images. Univariable Cox regression and least absolute shrinkage and selection operator (LASSO) regression were used to select features and generate a radiomics signature (radscore). The performance of the nomogram was evaluated by calibration curves, clinical practicability, and the c-index. Kaplan-Meier (KM) analysis was used to compare the overall survival (OS) between the two subgroups. The radiomics features of the NSCLC patients correlated significantly with survival time. The c-indexes of the nomogram in the training cohort, internal validation cohort, and external test cohort were 0.670, 0.658, and 0.660, respectively. The calibration curves showed that the predicted survival time was close to the actual survival time. Decision curve analysis shows that the nomogram could be useful in the clinic. According to KM analysis, the 1-, 2- and 5-year survival rates of the low-risk group were higher than those of the high-risk group. The nomogram, combining the radscore, clinicopathological factors, and conventional CT parameters, can improve the accuracy of survival prediction in patients with NSCLC.

ANALYSIS OF CIRCULATORY SYSTEM PATHOLOGIES IN HEAD CT DATA – HEMORRHAGE LOCALIZATION

Acute ischemic stroke and intracranial hemorrhages (ICH) represent critical situations for the patient. Rapid accurate diagnosis and therapy are required to prevent serious lifelong consequences or death. In the case of suspected head circulatory pathology, computed tomography (CT) is often the first choice among imaging techniques because of its availability, speed and reliability. In order to refine and speed up the diagnostic process, advanced algorithms implemented in computer aided diagnosis systems are currently being developed. This paper presents approaches to an automatic ICH localization as a part of a research project aimed at the development of machine learning methods for the analysis of circulatory disorders in head CT scans. Three designed deep learning-based algorithms are described and compared for prediction of the exact position of ICH within a 3D CT scan, and in two cases also for classification into the sub-types. An objective evaluation of the methods is presented along with a discussion of the results. Further possibilities for circulatory diseases analysis in head CT scans using modern algorithms are also discussed.

Inverted V-Shaped High Tibial Osteotomy Decreases the Posterior Tibial Slope More but Shortens the Tibia Less Than Closed-Wedge High Tibial Osteotomy

To assess the postoperative anatomical changes in the lower extremity after inverted V-shaped high tibial osteotomy (IVHTO) using 3-dimensional (3D) computed tomography (CT) bone models and compare those changes after closed-wedge high tibial osteotomy (CWHTO). Preoperative and 3-week postoperative CT scanning of the lower extremity were obtained from patients who underwent IVHTO and CWHTO between October 2019 and March 2021. 3D CT bone models were reconstructed using ZedKnee software. The postoperative changes (Δ) in (1) posterior tibial slope (PTS), (2) knee rotation angle (KRA), (3) tibial torsional angle (TTA), (4) patella tilt (PT), (5) Insall-Salvati ratio (ISR), and (6) tibial length (TL) were compared between IVHTO and CWHTO. Thirty-seven knees (18 IVHTO and 19 CWHTO) in 34 patients were retrospectively enrolled in this study. ΔPTS at the medial and lateral tibial plateau in the IVHTO group (-6.5° and -5.0°) was larger compared with that in the CWHTO group (-3.3° and -2.0°; P=.024 and P= .002, respectively). No significant differences exist between the IVHTO and CWHTO groups in ΔKRA (0.8± 4.5° and -1.5 ± 6.5°; P= 0.631), ΔTTA (-3.9 ± 6.2° and -4.1 ± 7.3°; P= .951), ΔPT (-2.0 ± 4.8° and -0.6 ± 4.1°; P=.353), and ΔISR (0.0 and 0.0; P= .829). ΔTL in the IVHTO group (-1.6 ± 2.3 mm) was smaller compared with that in the CWHTO group (-4.1 ± 1.6 mm; P < .001). (1) The postoperative PTS in the IVHTO group was further decreased compared to the CWHTO group; (2) no significant differences in ΔKRA, ΔTTA, ΔPT, and ΔISR exist between the 2 groups; and (3) the ΔTL in the IVHTO group was significantly smaller compared with the CWHTO group. Level III, retrospective cohort study.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma. A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated. Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively). A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

Robust weakly supervised learning for COVID-19 recognition using multi-center CT images

The world is currently experiencing an ongoing pandemic of an infectious disease named coronavirus disease 2019 (i.e., COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Computed Tomography (CT) plays an important role in assessing the severity of the infection and can also be used to identify those symptomatic and asymptomatic COVID-19 carriers. With a surge of the cumulative number of COVID-19 patients, radiologists are increasingly stressed to examine the CT scans manually. Therefore, an automated 3D CT scan recognition tool is highly in demand since the manual analysis is time-consuming for radiologists and their fatigue can cause possible misjudgment. However, due to various technical specifications of CT scanners located in different hospitals, the appearance of CT images can be significantly different leading to the failure of many automated image recognition approaches. The multi-domain shift problem for the multi-center and multi-scanner studies is therefore nontrivial that is also crucial for a dependable recognition and critical for reproducible and objective diagnosis and prognosis. In this paper, we proposed a COVID-19 CT scan recognition model namely coronavirus information fusion and diagnosis network (CIFD-Net) that can efficiently handle the multi-domain shift problem via a new robust weakly supervised learning paradigm. Our model can resolve the problem of different appearance in CT scan images reliably and efficiently while attaining higher accuracy compared to other state-of-the-art methods.