Axial CT Images Research Articles

ROLE OF POSTOPERATIVE CT SCAN IN ASSESSING SYNDESMOTIC REDUCTION IN ANKLE INJURIES

Background: Accurate syndesmotic reduction is necessary for achieving joint congruity and better functional outcomes. Radiographs alone don’t suffice, and CT scans are required for the evaluation of postoperative syndesmotic reduction. Methods: All patients who underwent ankle syndesmotic reduction and fixation from December 2019 to July 2021 were taken into the study. Predefined measurements were taken in postoperative radiographs and axial CT images were taken postoperatively. Sensitivity and specificity of X-rays when compared to CT scan were evaluated. Results: Twenty eight patients were included in the study and 13 cases were found to have syndesmotic malreduction in radiographs as per TCS and TFO in AP view and TFO and MCS measurements in mortise view. Five out of 28 cases were found to have syndesmotic malreduction in CT axial cuts as per standard anterior and posterior measurements. Hence 17.85% cases were malreduced in our study as per the gold standard (CT scan). The incidence of syndesmotic malreduction after fixation was 17.85%. Radiographs had a sensitivity of 60% and specificity of 56.5% in detecting malreduction. Conclusion: CT scan is necessary to accurately diagnose syndesmotic malreduction after open reduction and internal fixation of ankle fractures with associated syndesmotic injuries.

Evaluation of direct point dose estimation based on the distribution of the size-specific dose estimate.

The aim of this study was to evaluate the point doses using a distribution of the size-specific dose estimate (SSDE) from axial CT images of in-house phantoms having diameters from 8 to 40cm. In-house phantoms made of polyester-resin (PESR) mixed with methyl ethyl ketone peroxide (MEKP) were used. The phantoms were built with different diameter sizes of 8, 16, 24, 32, and 40cm. The phantoms were scanned by Siemens a SOMATOM Perspective-128 slice CT scanner with constant input parameters. The point doses were interpolated from the central SSDE (SSDEc) and the peripheral SSDE (SSDEp). The SSDEc and SSDEp were calculated from the SSDE with h- and k-factors. The point doses were compared to the direct measurements using the nanoDot™ optically-stimulated luminescence dosimeter (OSLD) in dedicated holes on the phantoms. It was found that the point dose decreases as the phantom diameter increased. The doses obtained using two approaches differed by 11% on average. The highest difference was 40% and the lowest difference was < 1%. It was found that dose based on the SSDE concept tended to be higher compared to the measured dose by OSLD. Point dose estimation using the concept of SSDE distribution can be considered an alternative for accurate and simple estimation. This approach still requires improvements to increase its accuracy and its application to estimate the organ dose needs further investigation.

Retrolabyrinthine Bone Thickness as a Radiologic Marker for the Hypoplastic Endotype in Menière Disease.

Menière disease (MD) manifests in 2 major endotypes: one with a hypoplastic, underdeveloped endolymphatic sac (MD-hp) and the other with a normally developed sac that degenerates over time (MD-dg). Determining the specific endotype in patients is important for predicting disease progression, tailoring patient counseling, and optimizing treatment strategies. Endotype diagnosis involves measuring an angular trajectory of the vestibular aqueduct (ATVA), with an ATVA ≥140° indicative of MD-hp and an ATVA ≤120° of MD-dg. However, assessing the ATVA can be challenging. This study aimed to explore the link between ATVA and the thickness of the retrolabyrinthine bone as an alternative diagnostic measure that could provide differentiation between MD endotypes using CT and MR imaging. Retrospective review of CT temporal bone imaging from 32 adult patients with definite MD (60 ears) and 33 age-matched controls without MD or other inner ear symptoms (61 ears) was performed. The ATVA and retrolabyrinthine bone thickness were measured using uniform methodology on standardized axial CT images. Comparative analyses were performed to determine the correlation between ATVA and retrolabyrinthine bone thickness. Additionally, from a separate cohort of 11 patients (22 ears), CT and MR examinations of the temporal bone were retrospectively reviewed for retrolabyrinthine bone thickness measurements, to verify the correlation across the 2 modalities. The average retrolabyrinthine bone thickness was statistically significantly different between MD endotypes, being a mean of 0.8 (SD, 0.3) mm in patients with MD-hp (ATVA ≥140°) and 2.0 (SD, 0.9) mm in patients with MD-dg (ATVA ≤120°), with a consistent pattern of thin retrolabyrinthine bone in MD-hp and variable thickness in MD-dg. Receiver operating characteristic curve analysis within the MD cohort revealed that a retrolabyrinthine bone thickness ≥1.2 mm effectively rules out MD-hp. Excellent interrater reliability was noted for the retrolabyrinthine measurement, and there was near-perfect correlation between CT and MR measurements. Retrolabyrinthine bone thickness proved to be a useful and straightforward alternative marker for distinguishing MD endotypes, being particularly useful for excluding MD-hp. Including information on retrolabyrinthine bone thickness should be considered a routine part of reporting in the context of MD imaging.

Study on the consistency between CBCT image features of sphenopalatine foramen and those seen in nasal endoscopy

Objective:To study the clinical anatomy of the sphenopalatine foramina by dissecting the sphenopalatine foramina during Vidian nerve branch neurotomy. The anatomy and CBCT images of sphenopalatine foramen were analyzed to facilitate the navigational of clinical operation using CBCT images. Methods:From October 2017 to September 2023, 84 cases（168 sides） of Vidian nerve branch neurotomy in our department were collected. The clinical summary was made according to the anatomy of sphenopalatine foramen during the operation. Preoperative CBCT imaging findings of the sphenopalatine foramina were also studied. Results:The clinical anatomy of sphenopalatine foramen could be divided into four types: middle meatus type（1.19%）, trans-meatus type（62.29%）, superior meatus type（33.33%） and double foramen type（1.19%）. The incidence of ethmoidal ridge was 98.81%. The distance from sphenopalatine foramina to posterior nasal canal were（14.63±2.66） mm to left and（14.65±2.63） mm to right, The position Angle ∠a of lower margin of sphenopalatine foramina were（62.36±10.05）° to left and（61.51±11.82）° to right, respectively. Axial CT images can be used to divide the sphenopalatine foramen into five levels: the upper edge of the sphenopalatine foramen level, the Vidian nerve level, the basal plate interaction level, the lower edge of the sphenopalatine foramen level and the pterygopalatine canal level. The agreement between endoscopic anatomy of sphenopalatine foramen and imaging navigation was 100%. Conclusion:The sphenopalatine foramina exhibit various anatomical types. The preoperative navigational CBCT reading can effectively identify the type of sphenopalatine foramina, guide the choice of surgical method, and help avoid serious complications. This has significant clinical application value.

Sarcopenia is independently associated with poor preoperative physical fitness in patients undergoing colorectal cancer surgery.

Accurate preoperative risk assessment for major colorectal cancer (CRC) surgery remains challenging. Body composition (BC) and cardiopulmonary exercise testing (CPET) can be used to evaluate risk. The relationship between BC and CPET in patients undergoing curative CRC surgery is unclear. Consecutive patients undergoing CPET prior to CRC surgery between 2010 and 2020 were identified between two different UK hospitals. Body composition phenotypes such as sarcopenia, myosteatosis, and visceral obesity were defined using widely accepted thresholds using preoperative single axial slice CT image at L3 vertebrae. Relationships between clinicopathological, BC, and CPET variables were investigated using linear regression analysis. Two hundred eighteen patients with stage I-III CRC were included. The prevalence of sarcopenia, myosteatosis, and visceral obesity was 62%, 33%, and 64%, respectively. The median oxygen uptake at anaerobic threshold (VO2 at AT) was 12.2mL/kg/min (IQR 10.6-14.2), and oxygen uptake at peak exercise (VO2 peak) was 18.8mL/kg/min (IQR 15.4-23). On univariate linear regression analysis, male sex (P<0.001) was positively associated with VO2 at AT. While ASA grade (P<0.001) and BMI (P=0.007) were negatively associated with VO2 at AT, on multivariate linear regression analysis, these variables remained significant (P<0.05). On univariate linear regression analysis, male sex (P<0.001) was positively associated with VO2 peak, whereas age (P<0.001), ASA grade (P<0.001), BMI (P=0.003), sarcopenia (P=0.015), and myosteatosis (P<0.001) were negatively associated with VO2 peak. On multivariate linear regression analysis age (P<0.001), ASA grade (P<0.001), BMI (P<0.001), and sarcopenia (P=0.006) were independently and negatively associated with VO2 peak. The novel finding that sarcopenia is independently associated with reduced VO2 peak performance in CPET supports the supposition that reduced muscle mass relates to poor physical function in CRC patients. Further work should be undertaken to assess whether sarcopenia diagnosed on CT can act as suitable surrogate for CPET to further enhance personalized risk stratification.

Assessment of Arterial Involvement in Pancreatic Cancer: Utility of Reconstructed CT Images Perpendicular to Artery.

The purpose of this study was to investigate the utility of reconstructed CT images perpendicular to the artery for assessing arterial involvement from pancreatic cancer and compare the interobserver variability between it and the current diagnostic imaging method. This retrospective study included patients with pancreatic cancer in the pancreatic body or tail who underwent preoperative pancreatic protocol CT and distal pancreatectomy. Five radiologists used axial and coronal CT images (current method) and perpendicular reconstructed CT images (proposed method) to determine if the degree of solid soft-tissue contact with the splenic artery was ≤180° or >180°. The generalized estimating equations were used to compare the diagnostic performance of solid soft-tissue contact >180° between the current and proposed methods. Fleiss' ĸ statistics were used to assess interobserver variability. The sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° were higher (p < 0.001 for each) and the specificity (p = 0.003) and positive predictive value (p = 0.003) were lower in the proposed method than the current method. Interobserver variability was improved in the proposed method compared with the current method (ĸ = 0.87 vs. 0.67). Reconstructed CT images perpendicular to the artery showed higher sensitivity and negative predictive value for diagnosing solid soft-tissue contact >180° than the current method and demonstrated improved interobserver variability.

Sarcopenia with decreased total psoas muscle area in children with high-risk neuroblastoma

BackgroundWe calculated psoas muscle area (PMA) z-scores in high-risk neuroblastoma patients undergoing treatment to examine the clinical significance of sarcopenia in this cohort. MethodsWe analyzed retrospective data from patients aged 0–18 who were diagnosed with abdominal neuroblastoma between 2005 and 2019 at Samsung Medical Center. Patients categorized as high-risk undergone induction chemotherapy, neuroblastoma excision, and tandem high-dose chemotherapy with autologous stem cell transplantation (HDCT/auto-SCT) were selected. L3-4 lumbar levels on axial CT images were identified and we measured the areas of the left and right psoas muscles to determine tPMA. Total PMA z-scores were calculated using an open online tool. ResultsThere were 45 boys and 25 girls with a mean age of 3.86 years. CT images taken at initial diagnosis and after tandem HDCT/auto-SCT were selected to calculate tPMA z-scores. Mean elapsed time between the two measurements was 12.91 ± 1.73 months. Mean tPMA z-score significantly decreased from −0.21 ± 1.29 to −0.66 ± 0.97 (p = 0.022). Length of hospital stay was significantly longer in the group of patients whose tPMA z-scores decreased by more than .45 (177.62 ± 28.82 days vs. 165.75 ± 21.34 days, p = 0.049). Presence of sarcopenia at initial diagnosis was a significant risk factor for bacterial infection during neuroblastoma treatment.Conclusion: tPMA z-scores in high-risk neuroblastoma patients decreased significantly following a treatment regimen that included induction chemotherapy, tumor resection surgery, and HDCT/auto-SCT. A greater decrease in tPMA z-score was associated with longer hospital stay during treatment.

Cervical Spine Fracture Detection Using Deep Learning

We've been looking into different disease detection models that use deep learning algorithms to look at medical radiograph images. Most of the studies have been done on lumbar spine diseases, but most of the studies were done on cervical spine diseases. Cervical radiculopathy is usually diagnosed based on MRI data, but it can be hard to diagnose even with an X-ray. MRI tests are expensive, so it can be hard for patients to get the right diagnosis. Cervical spine fractures are a medical emergency, and they can lead to permanent paralysis or even death. To make sure patients get the right diagnosis, it's important to use CT scans to check for fractures. We've come up with a Convolutional Neural Network (CNN) and Transfer Learning Model that can automatically detect cervical spine fractures from CT axial images, and we've trained and validated it using 4000 CT scans. We can even fine tune the transfer learning models to make it even more accurate. Keywords Convolutional Neural Networks, Computed tomography ,Deep learning , CT image , x ray , medical image , Spine disease , cervical spine fracture , Graphical user interface , Cervical radiculopathy.

Study on evaluation method of circular small shadow profusion in chest CT reconstruction images of pneumoconiosis

Objective: To select chest CT image patterns for the diagnosis of pneumoconiosis and establish a method for determining the profusion of circular small shadows in chest CT. Methods: In April 2021, 66 cases of occupational pneumoconiosis patients with digital radiography (DR) chest radiographs and chest CT imaging data with circular small shadow as the main manifestations were selected as the study objects. 1.5 mm and 5 mm chest CT axial images, 1 mm and 5 mm chest CT coronal multi-plane recombination (MPR) images, and 5 mm chest CT coronal maximum intensity projection (MIP) images were used to observe the different characteristics of pneumoconiosis patients, and were compared and analyzed with DR chest radiographs to establish the experimental chest CT standards. The consistency of the profusion results between the experimental chest CT standards and GBZ 70-2015 Diagnosis of Occupational Pneumoconiosis was verified. Results: All the 66 objects were male, including 33 cases of stage Ⅰ pneumoconiosis, 17 cases of stage Ⅱ pneumoconiosis and 16 cases of stage Ⅲ pneumoconiosis. By observing five chest CT images of 66 objects, we found that chest CT images of different modes could clearly display and identify abnormal images such as small circular shadow, large shadow, small shadow aggregation, honeycomb glass shadow, flake glass shadow, uniform low-profusion glass shadow, mesh glass shadow, cable shadow, linear shadow, subpleural spinous shadow, subpleural nodules, various kinds of emphysema and lung texture distortion and fracture. Small shadow aggregation was usually accompanied by the appearance of large shadow. The vascular shadows in 5 mm CT images had good ductility, and small nodules were easy to distinguish. The coronal MIP image of 5 mm chest CT used edge enhancement technology, which was prone to small shadow fusion and fibrotic shadow fusion. The coronal MPR image of 5 mm chest CT was highly consistent with the DR chest radiographs in terms of the integrity of film reading. GBZ 70-2015 standard was used to compare the profusion of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, and the consistency test Kappa=0.64. GBZ 70-2015 standard and experimental chest CT standard were used to compare the profusion results of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, respectively, and the consistency test Kappa=0.80, with high consistency. Conclusion: 5 mm coronal MPR image is suitable for chest CT imaging in the diagnosis of pneumoconiosis. Following the selection path and method of GBZ 70-2015 profusion criterion, the established experimental chest CT standard in determining the profusion of small circular shadows in 5 mm coronal MPR images of chest CT with pneumoconiosis has a high consistency with GBZ 70-2015 standard.

Abstract 3017: Fluorine-18 Sodium Fluoride Positron Emission Tomography/ Computed Tomography Imaging Of Calcium Progression In Patients With Peripheral Artery Disease

Introduction: Peripheral artery disease (PAD) is an atherosclerotic disease that promotes lower extremity ischemia and is associated with necrosis, limb loss, and premature death. Fluorine-18 sodium fluoride ( 18 F-NaF) PET/CT imaging has been utilized for early detection of calcific disease progression in the coronary arteries; however, this technique has not been assessed in PAD to predict developing arterial calcification. Hypothesis: We hypothesized that 18 F-NaF PET/CT imaging could identify sites undergoing active microcalcification and predict the formation or expansion of vascular calcium. Methods: Patients with PAD (n=26) underwent 18 F-NaF PET/CT imaging at baseline and CT imaging 18 months later. Regions of interest were manually drawn on axial PET and CT images for the arteries of the symptomatic limb (totaling 8,001 arterial segments). Arterial uptake of 18 F-NaF was quantified and reported on a segment-by-segment basis as maximum standard uptake values (SUV max ). Baseline and 18-month CT images were co-registered to quantify serial changes in calcium density for each arterial segment using CT image cutoffs for calcium (≥130 Hounsfield Units). Differences in arterial uptake of 18 F-NaF were compared across 3 categories of segments: 1) no calcium at baseline or 18 months, 2) newly formed calcium and 3) existing calcified lesions with expansion of calcium. Results: Arterial segments containing newly formed calcium had significantly higher baseline uptake of 18 F-NaF than segments without calcium progression. Existing calcified arterial lesions with progression showed significantly higher 18 F-NaF uptake compared to segments with newly formed calcium and segments without calcium progression ( Figure 1 ). Conclusions: In conclusion, calcium progression can be detected and potentially predicted using 18 F-NaF PET/CT imaging, thereby providing a molecular imaging tool for monitoring PAD pathophysiology and responses to medical therapy.

Computed tomography-based morphometric analysis of normal distal tibiofibular syndesmosis in the Indian population

BackgroundIn suspected Ankle Instability, the parameters that can be defined in the X-ray have their limitation owing to their variability in positioning and rotation of the tibiofibular joint. This inaccuracy further increases due to variability in morphometric parameters of distal tibiofibular syndesmosis among different populations based on race and sex. This research aims to study morphometry of normal distal tibiofibular syndesmosis based on computed tomography imaging in the Indian population. MethodsAn Prospective observational study was performed from December 2020 to October 2022 on normal ankle CT scans of 100 Indian population using axial, sagittal, and coronal CT images. Anterior and posterior tibiofibular distance, Morphology of the incisura fibularis based on depth, Tibiofibular clear space (TFCS) and tibiofibular overlap (TFO), Transverse and longitudinal length of the fibula, and Relationship between the center of the talus and the center of a line joining the outer aspect of malleoli in the coronal plane were measured and analyzed by two different observers. ResultsOut of the 100 participants, 77 (77 %) were male, and 23 (23 %) were female. The overall mean age of participants was 34.69 ± 9.7 years. The incisura fibularis was concave in 54 %, and shallow in 46 %. Anterior tibiofibular distance, Posterior tibiofibular distance, and Tibiofibular overlap were significantly different in comparison to the male with female populations (p-value < 0.05). ConclusionThis study gives the indices that describe normal variations in the anatomical relationship between the fibula and fibular incisure in the Indian population, which will be helpful for improving the diagnostic accuracy of distal tibiofibular syndesmoses and providing optimal treatment in order to improve functional outcomes and reduce the risk of complications. Level of EvidenceIII.

Improved intra-operative decision making in RA-TKR with the help of pre-operative CT scan

BackgroundRobotic-assisted total knee replacement (RA-TKR) is a significant advancement in orthopedic surgery, but intra-operative decision-making remains challenging. Pre-operative imaging techniques, particularly CT scans, have gained momentum, providing insights into the patient's anatomy, improving implant positioning and alignment. However, further research is needed to explore their influence on RA-TKR planning and execution. Materials and methodsThe hospital based cross-sectional study was conducted in Orthopedics department of Sparsh Speciality Hospital, Bangalore & Sunshine Hospital, Hyderabad. A total of 1020 participants in the age group over 50 years during the study period were included based on convenient sampling. The axial CT images were taken preoperatively and RA-TKA was done for all the patients. ResultsThe study participant's average age was 64.01 ± 7.13. Out of 1020 patients 259 (24.4%) were males and 761 (74.6%) were females. The median femoral, tibia and Polyethylene predicted and the actual component were same with the side of surgery and BMI. The median femoral predicted actual component was significantly higher among the age category of more than 80 years when compared to other age groups. The median femoral, tibia and Polyethylene predicted was higher in males when compared to females. ConclusionPre-operative CT scans enhance RA-TKR procedures by providing precise anatomical insights, enhancing implant placement, and identifying potential issues, improving surgical outcomes and patient satisfaction.

Evaluation of Pulmonary Nodules by Radiologists vs. Radiomics in Stand-Alone and Complementary CT and MRI.

Increased attention has been given to MRI in radiation-free screening for malignant nodules in recent years. Our objective was to compare the performance of human readers and radiomic feature analysis based on stand-alone and complementary CT and MRI imaging in classifying pulmonary nodules. This single-center study comprises patients with CT findings of pulmonary nodules who underwent additional lung MRI and whose nodules were classified as benign/malignant by resection. For radiomic features analysis, 2D segmentation was performed for each lung nodule on axial CT, T2-weighted (T2w), and diffusion (DWI) images. The 105 extracted features were reduced by iterative backward selection. The performance of radiomics and human readers was compared by calculating accuracy with Clopper-Pearson confidence intervals. Fifty patients (mean age 63 +/- 10 years) with 66 pulmonary nodules (40 malignant) were evaluated. ACC values for radiomic features analysis vs. radiologists based on CT alone (0.68; 95%CI: 0.56, 0.79 vs. 0.59; 95%CI: 0.46, 0.71), T2w alone (0.65; 95%CI: 0.52, 0.77 vs. 0.68; 95%CI: 0.54, 0.78), DWI alone (0.61; 95%CI:0.48, 0.72 vs. 0.73; 95%CI: 0.60, 0.83), combined T2w/DWI (0.73; 95%CI: 0.60, 0.83 vs. 0.70; 95%CI: 0.57, 0.80), and combined CT/T2w/DWI (0.83; 95%CI: 0.72, 0.91 vs. 0.64; 95%CI: 0.51, 0.75) were calculated. This study is the first to show that by combining quantitative image information from CT, T2w, and DWI datasets, pulmonary nodule assessment through radiomics analysis is superior to using one modality alone, even exceeding human readers' performance.

An analysis of muscle growth after proton beam therapy for pediatric cancer.

Retardation of growth and development is a well-known late effect after radiotherapy for pediatric patients. The goal of the study was to examine the effect of proton beam therapy (PBT) on the growth of muscles included in the irradiated area. The subjects were 17 pediatric patients (age ≤ 5years) who received PBT with a treatment field including a muscle on only one side out of a pair of symmetrical bilateral muscles and had imaging evaluations for at least 1year after PBT. The thicknesses of the irradiated and non-irradiated (contralateral) muscles were measured retrospectively on CT or MRI axial images collected before and after PBT. The change of thickness divided by the period (years) for each muscle was compared between the irradiated and contralateral sides. Correlations of muscle growth with irradiation dose and age at the start of treatment were also evaluated. The median observation period was 39.2months. The measurement sites included the erector spinae (n = 9), gluteus maximus (n = 5) and rhomboids + trapezius (n = 3) muscles. The average changes in muscle thickness were 0.24mm/year on the irradiated side and 1.19mm/year on the contralateral side, showing significantly reduced growth on the irradiated side (P = 0.001). Younger patients had greater muscle growth. Irradiation dose was not significant, but muscle growth tended to decrease as the dose increased, and muscles irradiated at >50Gy (RBE) showed little growth. These results show that muscle growth is affected by PBT and that long-term follow-up is needed to evaluate muscle growth retardation.

Anatomical Dimensions and Types of the Anterior Clinoid Process in Libyan population by Using Computed Tomography: A cross Sectional Study

The anterior clinoid process (ACP) has a complex anatomical feature and surrounded by important structures which may complicate the surgical procedures during the anterior clinoidectomy. Our objective was to measure dimensions of anterior clinoid process, and to determine variations of its types. Forty-nine of cranial computed tomography scans were performed from adult Libyan patients on routine examination of paranasal sinus at Benghazi Medical Center between February 1, 2023, and April 14, 2023. The right and left ACP length and the base width were measured on the axial CT images. Data analysis was done using SPSS version 23. The means and standard deviations were calculated. The paired Student’s t test was used to determine the statistically significant differences in means between the right and left ACP. (P ≤ 0.05) was considered statistically significant at (95%) confidence interval. The length of the right and left ACPs were 11.2 ± 2.2 mm and 11.6 ± 2.4mm, respectively. The width of the right and left ACPs were 5.37± 1.22 mm and 5.42 ± 1.24mm, respectively. Type 2 anterior clinoid process was the commonest (75.5 %) while type 1 was the least common (4.1 %). There was no statistically significant difference between right and left sided measurements. Our study outcomes may be helpful for pre-operative planning. Presence of any variations may result in unnecessary injury to the complicated surgical procedures that involve removal of ACPs. Further research studies required with large sample size of population will give well understanding about the parameter of ACPs.

Performance of modified ResNet model for calcium score from non-contrast computed tomography

Abstract Aims Calcium score measured from non-contrast CT is considered as the reference method for risk assessment of coronary artery disease. We aimed to develop a modified ResNet layers model for calcium score assessment in a cohort of multi-ethnic Asian patients with suspected coronary artery disease. Methods This is a multicenter study which performs CT scans in 5000 Asian Admixture patients in Singapore from 3 different hospitals (APOLLO study). In this current study, 369 subjects (mean age 56 ± 11 years; 147 female) were analyzed. Of these patients, 36% were shown to have very low risk (CAC = 0), 49% had mildly increased risk (CAC = 1–99), 11% had moderately increased risk (CAC = 100–299), and 5% had moderate to severe risk (CAC&amp;gt;300). The number of labelled 2D axial calcium lesions were as follows: LAD – 929, LM – 101, LCX – 545 and RCA – 940. Data augmentation was carried out to increase the overall sample size and balance number of labelled calcium lesions in the dataset. The dataset was split at the patient level prior to data augmentation to prevent any data leakage issues (60% Training: 20% Validation and 20% Test). The calcium score model was developed by consisting of three modified ResNet layers (MRN), and a series of fully connected layers. Axial, coronal and sagittal CT images were fed into the modified ResNet individually and the output of the model was the probability of the calcium lesion being in any of the four arteries. Cross-entropy loss was used as the loss function during the training process, while F1 score was used to evaluate the model performance at per-voxel level. Results The correlation coefficient between our MRN model and clinical ground truth for the total calcium score was r = 0.90 (P &amp;lt; 0.0001). The MRN model performed well in detecting the location of calcium lesions belonging to any of the three arteries, with accuracies of 0.95 in LAD, 0.90 in LCX, and 0.80 in RCA. Additionally, the MRN model demonstrated good diagnostic accuracy, F1 score, and intra-class correlation coefficient (ICC) of 0.80, 0.79, and 0.92, respectively, in predicting the CAC risk categories (low, mildly increased risk, moderately increased risk, and moderately to severely increased risk). A confusion matrix for the CAC risk category between the expert reader and MRN is shown in Figure 1. Conclusion Our modified ResNet-based machine learning model attained excellent prediction of calcium score using non-contrast CT. Figure 1.Confusion matrix for CAC risk.

Analysis of vascular perfusion territory using selective intraarterial injection CT angiography before and after revascularization surgery in patients with moyamoya disease.

In moyamoya disease (MMD), blood flow to the internal carotid artery (ICA) system is supplied via the basal fine vascular network, leptomeningeal anastomoses, and transdural collateral vessels from the external carotid artery (ECA). After revascularization, there is a dramatic change in cerebral perfusion to the ECA system. Understanding this shift in blood supply is important for evaluating treatment efficacy and elucidating the postoperative pathophysiology. However, anatomical and quantitative methods for doing so have not yet been established. In the present study, selective intraarterial injection CT angiography (iaCTA) was performed in patients with MMD, and blood supply changes in each arterial system before and after revascularization surgery were evaluated. This study included 10 hemispheres in 10 patients who underwent combined revascularization surgery for adult MMD. Digital subtraction angiography was performed before and 3 months after surgery, and selective iaCTA was performed from the ICA, ECA, and vertebral artery (VA) at the same times in a hybrid CT/digital subtraction angiography suite. The anatomical distribution of each vessel was determined and perfusion volume was measured quantitatively on contrast-enhanced axial CT images. Selective iaCTA clearly depicted the anatomical distribution of perfusion for each vessel. Conversion of blood supply from the ICA and VA to the ECA system was observed in the cerebral cortices and insulae but not in the basal ganglia. The mean volume of perfusion territories of the ECA (preoperative 0.9 cm3, postoperative 98.8 cm3); ICA (preoperative 225.7 cm3, postoperative 159.3 cm3); and VA (preoperative 244.0 cm3, postoperative 163.6 cm3) in the cerebral hemispheres changed significantly after revascularization. There was a correlation between increase in the ECA territory volume and decrease in the VA territory volume due to revascularization (R = -0.84, p < 0.005). Selective iaCTA enabled clear visualization of anatomical changes in each vascular perfusion territory and quantitative measurement of each perfusion volume. Perfusion conversion to the ECA system after bypass surgery was observed in the cortical regions and in the insulae on the bypass operation sides, but not in the basal ganglia. Combined revascularization promoted the development of ECA-perfused territory, which correlated with a decrease in hemodynamic burden of the posterior cerebral artery.

Decoding tumor stage by peritumoral and intratumoral radiomics in resectable esophageal squamous cell carcinoma

PurposeTo evaluate the potential application of radiomics in predicting Tumor-Node-Metastasis (TNM) stage in patients with resectable esophageal squamous cell carcinoma (ESCC).MethodsThis retrospective study included 122 consecutive patients (mean age, 57 years; 27 women). Corresponding tumor of interest was identified on axial arterial-phase CT images with manual annotation. Radiomics features were extracted from intra- and peritumoral regions. Features were pruned to train LASSO regression model with 93 patients to construct a radiomics signature, whose performance was validated in a test set of 29 patients. Prognostic value of radiomics-predicted TNM stage was estimated by survival analysis in the entire cohort.ResultsThe radiomics signature incorporating one intratumoral and four peritumoral features was significantly associated with TNM stage. This signature discriminated tumor stage with an area under curve (AUC) of 0.823 in the training set, with similar performance in the test set (AUC 0.813). Recurrence-free survival (RFS) was significantly different between different radiomics-predicted TNM stage groups (Low-risk vs high-risk, log-rank P = 0.004). Univariate and multivariate Cox regression analyses revealed that radiomics-predicted TNM stage was an independent preoperative factor for RFS.ConclusionsThe proposed radiomics signature combing intratumoral and peritumoral features was predictive of TNM stage and associated with prognostication in ESCC.Graphical abstract

VMAT-IGRT Hypofractionated Radiotherapy for Locally Advanced Thyroid Cancer in Resource-Limited Settings: A Retrospective Report from Bolivia

This study evaluated the efficacy and safety of hypofractionated external beam irradiation with VMAT-IGRT in patients with locally advanced thyroid cancer (LATC) who are ineligible for surgery or I-131 in a resource-limited setting such as Bolivia. Thirty-three patients were treated with H-VMAT-IGRT between August 2018 and November 2022. Axial CT images were acquired every 3 mm from the base of the skull to the middle of the chest. GTV was determined based on contrast-enhanced tumor on T1 MRI or CT scans. CTV 55 Gy at 2.75 Gy was defined based on visible residual tumor and included dissected nodal stations with pathologically positive nodes. CTV 44 at 2.2 Gy for non-dissected nodal stations with low risk of recurrence, we escalated the dose up to 60 Gy at 3 Gy for small tumors up to 20 cc. PTVs were created by adding a 0.3 cm margin around CTVs, with a reduced margin of minus 3-5 mm for critical organs such as esophagus, pharynx, and brachial plexus. Equivalent dose in 2Gy (EQD2 10-3) was reported for tumor control and OAR constraints. Acute toxicity was reported according to RTOG criteria, and response to treatment was assessed at baseline, end of treatment, and every third month thereafter. The mean time since last follow-up was 24 months (r: 8-40). Patients were 80% female and 20% male. The mean age was 50 years (r: 29-72). Local recurrence was treated in 52% (13) of patients and LATC in 48% (12). Papillary carcinomas accounted for 68% of patients, followed by anaplastic (24%) and follicular (8%) carcinomas. Tumors were classified according to the AJCC classification. Of the patients treated for LATC, 25% were at stage II, 25% at stage III, 16.67% at stage IVA, and 33.33% at stage IVB. Among patients treated for local recurrence, the initial stage before progression was stage I in 61.5%, stage II in 30.8%, and stage IVA in 7.7%. The median PTV was 383.8 cc (r: 51.7 - 627.3) and the median CTV55 was 189.2 cc (r: 39.6 - 519.8). Grade 1 (10%), Grade 2 (90%) dysphagia, Grade 1 (40%), Grade 2 (60%) acute pharyngeal mucositis, and no Grade 3 acute toxicity were observed. No reports of chronic upper damage GI, 30% xerostomia G2. Two-year local control was 70% and overall survival was also 70%. We suggest that reducing treatment duration while maintaining efficacy is particularly beneficial in resource-limited areas with a shortage of trained personnel and overburdened treatment centers. We report good local control rates with no detrimental effects on quality of life with hypofractionation. No evidence of delayed damage, such as spinal cord dysfunction, mandibular osteoradionecrosis, or brachial plexopathy, was noted. We emphasize the importance of using VMAT with IGRT for reliable and accurate daily treatment of the target area, while minimizing side effects. However, these results should be confirmed with a larger sample of patients.

The pedicle screw accuracy using a robotic system and measured by a novel three-dimensional method

Robotics in medicine is associated with precision, accuracy, and replicability. Several robotic systems are used in spine surgery. They are all considered shared-control systems, providing "steady-hand" manipulation instruments. Although numerous studies have testified to the benefits of robotic instrumentations, they must address their true accuracy. Our study used the Mazor system under several situations and compared the spatial accuracy of the pedicle screw (PS) insertion and its planned trajectory. We used two cadaveric specimens with intact spinal structures from C7 to S1. PS planning was performed using the two registration methods (preopCT/C-arm or CT-to-fluoroscopy registration). After planning, the implant spatial orientation was defined based on six anatomic parameters using axial and sagittal CT images. Two surgical open and percutaneous access were used to insert the PS. After that, another CT acquisition was taken. Accuracy was classified into optimal, inaccurate and unacceptable according to the degree of screw deviation from its planning using the same spatial orientation method. Based on the type of spatial deviation, we also classified the PS trajectory into 16 pattern errors. Seven (19%) out of 37 implanted screws were considered unacceptable (deviation distances > 2.0 mm or angulation > 5°), and 14 (38%) were inaccurate (> 0.5 mm and ≤ 2.0 mm or > 2.5° and ≤ 5°). CT-to-fluoroscopy registration was superior to preopCT/C-arm (average deviation in 0.9 mm vs. 1.7 mm, respectively, p < 0.003), and percutaneous was slightly better than open but did not reach significance (1.3 mm vs. 1.7 mm, respectively). Regarding pattern error, the tendency was to have more axial than sagittal shifts. Using a quantitative method to categorize the screw 3D position, only 10.8% of the screws were considered unacceptable. However, with a more rigorous concept of inaccuracy, almost half were non-optimal. We also identified that, unlike some previous results, the O-arm registration delivers more accurate implants than the preopCT/C-arm method.