4DCT Scans Research Articles

Clinical implications of dose to functional lung volumes in the trimodality treatment of esophageal cancer

Background Trimodality treatment, i.e., neoadjuvant chemoradiotherapy (nCRT) followed by surgery, for locally advanced esophageal cancer (EC) improves overall survival but also increases the risk of postoperative pulmonary complications. Here, we tried to identify a relation between dose to functional lung volumes (FLV) as determined by 4D-CT scans in EC patients and treatment-related lung toxicity. Materials and methods All patients with EC undergoing trimodality treatment between 2017 and 2022 in UZ Leuven and scanned with 4D-CT-simulation were selected. FLVs were determined based on Jacobian determinants of deformable image registration between maximum inspiration and expiration phases. Dose/volume parameters of the anatomical lung volume (ALV) and FLV were compared between patients with versus without postoperative pulmonary complications. Results of pre- and post-nCRT pulmonary function tests (PFTs) were collected and compared in relation to radiation dose. Results Twelve out of 51 EC patients developed postoperative pulmonary complications. ALV was smaller while FLV10Gy and FLV20Gy were larger in patients with complications (respectively 3141 ± 858mL vs 3601 ± 635mL, p = 0.025; 360 ± 216mL vs 264 ± 139mL, p = 0.038; 166 ± 106mL vs 118 ± 63mL, p = 0.030). No differences in ALV dose-volume parameters were detected. Baseline FEV1 and TLC were significantly lower in patients with complications (respectively 90 ± 17%pred vs 102 ± 20%pred, p = 0.033 and 93 ± 17%pred vs 110 ± 13%pred, p = 0.001), though no other PFTs were significantly different between both groups. DLCO was the only PFT that had a meaningful decrease after nCRT (85 ± 17%pred vs 68 ± 15%pred, p < 0.001) but was not related to dose to ALV/FLV. Conclusion Small ALV and increasing FLV exposed to intermediate (10 to 20 Gy) dose are associated to postoperative pulmonary complications. Changes of DLCO occur during nCRT but do not seem to be related to radiation dose to ALV or FLV. This information could attribute towards toxicity risk prediction and reduction strategies for EC.

Full-sized realistic 3D printed models of liver and tumour anatomy: a useful tool for the clinical medicine education of beginning trainees

BackgroundSimulation-based medical education (SBME) and three-dimensional printed (3DP) models are increasingly used in continuing medical education and clinical training. However, our understanding of their role and value in improving trainees’ understanding of the anatomical and surgical procedures associated with liver surgery remains limited. Furthermore, gender bias is also a potential factor in the evaluation of medical education. Therefore, the aim of this study was to evaluate the educational benefits trainees receive from the use of novel 3DP liver models while considering trainees’ experience and gender.MethodsFull-sized 3DP liver models were developed and printed using transparent material based on anonymous CT scans. We used printed 3D models and conventional 2D CT scans of the liver to investigate thirty trainees with various levels of experience and different genders in the context of both small group teaching and formative assessment. We adopted a mixed methods approach involving both questionnaires and focus groups to collect the views of different trainees and monitors to assess trainees’ educational benefits and perceptions after progressing through different training programs. We used Objective Structured Clinical Examination (OSCE) and Likert scales to support thematic analysis of the responses to the questionnaires by trainees and monitors, respectively. Descriptive analyses were conducted using SPSS statistical software version 21.0.ResultsOverall, a 3DP model of the liver is of great significance for improving trainees’ understanding of surgical procedures and cooperation during operation. After viewing the personalized full-sized 3DP liver model, all trainees at the various levels exhibited significant improvements in their understanding of the key points of surgery (p < 0.05), especially regarding the planned surgical procedure and key details of the surgical procedures. More importantly, the trainees exhibited higher levels of satisfaction and self-confidence during the operation regardless of gender. However, with regard to gender, the results showed that the improvement of male trainees after training with the 3DP liver model was more significant than that of female trainees in understanding and cooperation during the surgical procedure, while no such trend was found with regard to their understanding of the base knowledge.ConclusionTrainees and monitors agreed that the use of 3DP liver models was acceptable. The improvement of the learning effect for practical skills and theoretical understanding after training with the 3DP liver models was significant. This study also indicated that training with personalized 3DP liver models can improve all trainees’ presurgical understanding of liver tumours and surgery and males show more advantage in understanding and cooperation during the surgical procedure as compared to females. Full-sized realistic 3DP models of the liver are an effective auxiliary teaching tool for SBME teaching in Chinese continuing medical education.

Novel simulation for dosimetry impact of diaphragm respiratory motion in four-dimensional volumetric modulated arc therapy for esophageal cancer

Background and purposeThe diaphragm respiratory motion (RM) could impact the target dose robustness in the lower esophageal cancer (EC). We aimed to develop a framework evaluating the impact of different RM patterns quantitatively in one patient, by creating virtual four-dimensional computed-tomography (v4DCT) images, which could lead to tailored treatment for the breathing pattern. We validated virtual 4D radiotherapy (v4DRT) along with exploring the acceptability of free-breathing volumetric modulated arc therapy (FB-VMAT). Methods and MaterialsWe assessed 10 patients with superficial EC through their real 4DCT (r4DCT) scans. v4DCT images were derived from the end-inhalation computed tomography (CT) image (reference CT) and the v4DRT dose was accumulated dose over all phases. r4DRT diaphragm shifts were applied with magnitudes derived from r4DCT scans; clinical target volume (CTV) dose of v4DRT was compared with that of r4DRT to validate v4DRT. CTV dosage modifications and planning organ at risk volume (PRV) margins of the spinal cord were examined with the diaphragm movement. The percentage dose differences (ΔDx) were determined between the v4DRT and the dose calculated on the reference CT image. ResultsThe CTV ΔDx between the r4DRT and v4DRT were within 1% in cases with RM ≦ 15 mm. The average ΔD100% and ΔDmean of the CTV ranging from 5 to 15 mm of diaphragm motion was 0.3% to 1.7% and 0.1% to 0.4%, respectively. All CTV index changes were within 3% and ΔD1cc and ΔD2cc of Cord PRV were within 1%. ConclusionWe postulate a novel method for evaluating the CTV robustness, comparable to the conventional r4DCT method under the diaphragm RM ≦ 15 mm permitting an impact of within 3% in FB-VMAT for EC on the CTV dose distribution.

Diagnostic Value of Four-Dimensional Dynamic Computed Tomography for Primary Hyperparathyroidism in Patients with Low Baseline Parathyroid Hormone Levels.

Low baseline levels of parathyroid hormone (PTH) are associated with a higher rate of multiglandular disease, lower localization rates of preoperative imaging modalities, and a higher rate of unsuccessful minimally invasive parathyroidectomies. The objective of this study is to assess the diagnostic value of four-dimensional dynamic computed tomography (4D-CT) in localizing primary hyperparathyroidism (pHPT) in patients with low baseline PTH levels, compared to patients with high baseline PTH levels. Patients with pHPT who received a 4D-CT scan as part of their standard diagnostic evaluation were divided into two groups based on the following criteria: (1) preoperative PTH levels less than 100 pg/mL and (2) patients with preoperative PTH levels greater than 100 pg/mL. All patients underwent parathyroidectomy based on 4D-CT findings, with intraoperative parathyroid hormone monitoring. The lesion-based sensitivity of 4D-CT was 88% in patients with low baseline PTH levels and 94.7% in patients with high baseline PTH levels (p = 0.33). However, the success rate of image-guided resection based on 4D-CT findings was 71.4% in the low baseline PTH group compared to 90.6% in the high baseline PTH group (p = 0.06). Our study demonstrated that 4D-CT has a high lesion-based sensitivity in patients with pHPT and low baseline PTH levels but led to a relatively low rate of successful image-guided resection in patients with low baseline PTH levels. Therefore, it is important to exercise increased caution during 4D-CT-guided surgical exploration of patients with low baseline PTH levels to ensure successful surgical resection of all parathyroid lesions.

Characterization of internal pore size distribution and interconnectivity for asphalt concrete with various porosity using 3D CT scanning images

The open pore characteristics of asphalt mixtures play a crucial role in their resistance to water-induced damage. Accurate extraction and analysis of the pore structures at a micro level can reveal the seepage characteristics of asphalt pavements. However, existing studies mainly focus on the through-pore characteristics of porous asphalt mixtures and there is a lack of research on the open pore characteristics and interconnected paths of dense graded asphalt mixtures. This study aims to fill this gap by using 3D X-ray computed tomography technology to analyze the digital images of three typical asphalt mixtures with different porosities. The study quantitatively and statistically analyzes several new pore structure parameters at a micro level, such as porosity, equivalent diameter, coordination number, pore throat dimension, and tortuosity. The interconnected paths of the pores are also compared and analyzed. The results show that as the total pores content increases, the difference between the pore fraction and open pores fraction decreases. The porosity of porous asphalt mixtures is high, but mainly composed of interconnected pores with only a small proportion of closed pores. The coordination number determines the connectivity and thus the porosity of the asphalt mixture, and larger open pore channels lead to larger pore diameters and greater permeability. As the porosity of the asphalt mixture increases, the average coordination number of its internal pores also increases, leading to better pore connectivity and a more complex pore network.

Combined femoral and tibial component total knee arthroplasty device rotation measurement is reliable and predicts clinical outcome

BackgroundThe optimal total knee arthroplasty (TKA) rotational alignment and how best to obtain and measure it are debatable. The aim was to analyse the reliability of the Berger femoral, three different tibial and four different combined two-dimensional computer tomography (2D-CT) TKA component rotation measurements, and to ascertain which rotational values best predict a successful clinical outcome.MethodsThe 2D-CT scans were obtained post-operatively on 60 patients who had TKA. We determined one femoral [Berger’s femoral angle (BFA)], three tibial [Berger’s tibial angle (BTA), anatomical tibial angle (ATA) and bimalleolar posterior tibial component angle (BM_PTCA)] and four combined [transepicondylar posterior tibial component angle (TE_PTCA), bicondylar posterior tibial component angle (BC_PTCA, transepicondylar bimalleolar angle (TE_BM) and bicondylar bimalleolar angle (BC_BM)] TKA rotation angles. We made all measures in 23 patients twice by three observers and determined inter- and intra-observer agreement using the Bland–Altman plot method. We analysed measures of 55 patients using the area under the ROC curve (AUC) analysis to ascertain the discriminative capacity of BFA, ATA, TE_PTCA and BC_PTCA for predicting a successful clinical outcome according to the Knee Society Score (KSS) threshold.ResultsATA showed the smaller inter- and intra-observer average of differences (−0.1° and 1.6°, respectively) of the studied methods followed by BFA (−0.9° and 1.4°), TE_PTCA (−2.1° and 2.7°) and BC_PTCA (−0.5° and 1.8°). BFA (−4° to 2.1° and −6.1° to 8.8°) and BC_PTCA (−4.4° to 3.4° and −7.9° to 4.4°) showed the narrower inter- and intra-observer limits of agreement. A TKA device rotation (BC_PTCA) < 0.8° of external rotation (ER) predicted a KSS and KSS knee successful outcome, and < 3.8° ER for KSS functional (AUC = 0.889; 0.907 and 0.764, respectively). BFA and ATA < 0.9° ER and < 3.9° internal rotation (IR) predicted a successful KSS knee outcome (AUC = 0.796 and 0.889, respectively).ConclusionThe ATA tibial component rotation measurement was the most reliable of those studied. BFA, TE_PTCA and BC_PTCA were reliable measures for TKA femoral and combined rotation. The presence of a minimal rotation between the TKA components (BC_PTCA) and a small femoral ER or tibial IR predicted a successful KSS outcome.Level of evidence II.

Clinical evaluation of 4D dynamic dose for thoracic tumor stereotactic body radiation therapy with variable parameters

ObjectiveTo evaluate the dose uncertainty in stereotactic body radiation therapy induced by respiratory motion using a 4D dynamic dose (4DDD) reconstruction method. MethodsA retrospective analysis was conducted on five lung cancer patients who received static intensity-modulated radiation therapy. The 4DDD was constructed using beam delivery log files, four-dimensional computed tomography (4DCT) scans, and treatment plans. To evaluate the impact of respiratory motion, 4DDD calculations were performed with 10 starting phases for each field. A total of 270 field doses were simulated and calculated. The differences between the cumulative volume histogram in whole-course treatment and the field doses' gamma passing rate (GPR) were compared. The correlations between plan complexity metrics and the dose deviation caused by respiratory motion were evaluated independently. The phase distributions of 398 subfields were calculated and evaluated for the influence of dose rate and breathing frequency. ResultsThe GPRs of all fields were different among various starting phases, with the highest range from 62.20% to 76.87% for 2 mm/3% GPR. The deviation of mean point dose was (5.42 ​± ​5.21) %, and the deviation in the mean dose and D98% within the internal gross tumor volume were (0.97 ​± ​0.71) % and (0.77 ​± ​0.53) %, respectively. There was a significant correlation between the beam aperture-to-volume (BA2V) ratio and the average 2 mm/2% GPR (R ​= 0.601, P ​< ​0.01). Lower dose rates led to a more homogeneous distribution of phases among subfields (t ​= ​44.100, P ​< ​0.001). ConclusionsDifferent beam starting phases had a limited impact on the overall treatment evaluation. However, the respiratory motion could be observed to induce dose deviations using the 4DDD reconstruction model, particularly for fields with small BA2V.

Local control and toxicity after magnetic resonance imaging (MR)-guided single fraction lung stereotactic ablative radiotherapy

PurposeMagnetic resonance imaging (MR)-guided radiotherapy permits continuous intrafraction visualization and use of automatic triggered beam delivery, with use of smaller planning target volumes (PTV). We report on long-term clinical outcomes following MR-guided single fraction (SF) lung SABR on a 0.35 T linac. Materials and MethodsDetails of patients treated with SF-SABR for lung tumors were accessed from an ethics approved institutional database. A breath-hold 3D MR simulation scan was performed using a true FISP sequence, followed by a breath-hold 3D CT scan. The gross tumor volume (GTV) was first contoured on the breath-hold CT scan, which was then compared with contours on the 3D MR scan, before the GTV was finalized. SABR plans used step-and-shoot IMRT beams to a PTV derived by adding a 5 mm margin to the breath-hold GTV, and a 3 mm gating window was used. SABR was delivered during repeated breath-holds, using automatic beam gating with continuous visualization of the GTV in a sagittal MR plane. ResultsBetween 2018–2022, 50 consecutive patients were treated, and 69% had a primary non-small cell lung cancer. Median PTV was 11.2 cc (range 3.9–53.5); 80% of GTV’s were located ≤2.5 cm from the chest wall. Prescribed doses were 34 Gy (in 58%), 30 Gy (32%), or between 20–28 Gy (10%). After a median follow-up of 18.1 months (95% CI 12.8–23.5), the 2-year survival was 82% (89% for primary NSCLC and 62% for metastases). After a median follow-up of 16.1 months (95% CI 11.2–21.1), local recurrences developed in 2 patients (4%). The 3-year local control rate was 97%, and just 1 patient developed grade ≥3 toxicity (chest wall pain). ConclusionMR-guided SF-SABR delivery to lung tumors on a 0.35 T linac, using repeated breath-holds with automatic beam gating, achieves good tumor control and low toxicity.

Yoke procedure as a salvage treatment option for failed reverse total shoulder arthroplasty with irreconstructible glenoid

Glenoid bone loss is a known challenge in primary and revision reverse total shoulder arthroplasty. In severe deficiency, even placing the baseplate in alternative centerline or using an augmented baseplate may be insufficient. This study reports on the use of a soft tissue resurfacing technique using Achilles tendon allograft, coined Yoke procedure, for salvage treatment of glenoid deficient shoulder requiring reconstruction. All patients who underwent the Yoke procedure between 2014 and 2020 by a single surgeon at a single academic center were identified and had their charts retrospectively reviewed. Demographics and surgical information were recorded. Preoperative X-rays and 3D-CT scans were reviewed to classify patient glenoid types, evaluate glenoid medialization, and measure shoulder angles. Preoperative and postoperative range of motion (ROM) and patient-reported outcome scores were evaluated, including anterior elevation (AE), external rotation (ER), internal rotation (IR), Visual Analog Scale (VAS), Subjective Shoulder Score (SSV), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores. Postoperative radiographs and follow-up notes were reviewed to evaluate postoperative complication profiles at 1 year. Seven patients with median age of 69 years (range 54-77) underwent Yoke procedure and had median 12-month follow-up (range 9 - 56). All patients were female and had median of 2 prior shoulder surgeries (range 0-13). Of all the patients, the most common comorbidity was osteoporosis (6) followed by rheumatoid arthritis (3). Of the 5 patients who had previous arthroplasty, the most common indications were baseplate failure (4), followed by instability (3) and infection (3). Median VAS score improved from 8 (range 3-9) to 2 (range 1-4). Median SST improved from 8% (range 0-42%) to 33% (range 17-83%). Median ASES score improved from 15 (range 5-38) to 52 (range 40-78). Median AE and ER improved from 20° (range 0°- 75°) to 100° (range 40°- 145°) and 10° (range 0°- 20°) to 20° (range 0°- 55°), respectively. There was no change in median IR. As of last follow-up, one patient reported postoperative complications of anterior superior implant escape, heterotopic ossification, and scapular notching. The Yoke procedure is a promising salvage treatment that can offer patients consistent pain reduction and moderate functional improvements at short-term follow-up. In the setting of poor bone quality and severe glenoid deficiency, glenoid baseplate implantation may not be absolutely necessary for a pain-relieving, functionally acceptable outcome.

Deep Reinforcement Learning Method for 3D-CT Nasopharyngeal Cancer Localization with Prior Knowledge

Fast and accurate lesion localization is an important step in medical image analysis. The current supervised deep learning methods have obvious limitations in the application of radiology, as they require a large number of manually annotated images. In response to the above issues, we introduced a deep reinforcement learning (DRL)-based method to locate nasopharyngeal carcinoma lesions in 3D-CT scans. The proposed method uses prior knowledge to guide the agent to reasonably reduce the search space and promote the convergence rate of the model. Furthermore, the multi-scale processing technique is also used to promote the localization of small objects. We trained the proposed model with 3D-CT scans of 50 patients and evaluated it with 3D-CT scans of 30 patients. The experimental results showed that the proposed model has strong robustness, and its accuracy was improved by more than 1 mm on average under the premise of using a smaller dataset compared with the DQN models in recent studies. The proposed model could effectively locate the lesion area of nasopharyngeal carcinoma in 3D-CT scans.

A rare case surgery repair for pediatric sphenoethmoidal encephalocele with single-step transfrontobasal approach

Link of Vidio Abstract: https://youtu.be/nsnfWQ81oRU Background: Basal encephalocele (BEC) is the rarest type of all encephaloceles. Several methods were used to close and repair the bony defect and prevent CSF leakage. Here we present a case of a 1-month-old pediatric patient who presented with a sphenoethmoidal basal encephalocele with a single transfrontobasal approach. Case Presentation: A female infant one-month-old with diagnosed large sphenoethmoid encephalocele (basal encephalocele). From the 3D CT scan reconstruction, we found a defect in the planum sellae and ethmoid region with a maximum line of 2.84 cm x 2.89 cm. We performed a transfrontobasal approach by using titanium mesh/plate. After follow-up, we did not find CSF leakage. Conclusion: Uncertainty persists on the best way to restore BEC. In this instance, we used single TBF approaches to seal and repair the basal encephalocele. There are no signs of infection or CSF leakage throughout the follow-up.

Poster 245: Clinical Measurement of the Standard Q-Angle Correlates Poorly with Tibial Tuberosity to Trochlear Groove Distance in Awake Patients and Anesthetized Patients with Patella Alta and Trochlear Dysplasia

Objectives: The quadriceps angle (Q-angle) measures the force vector of pull of the extensor mechanism of the knee. A larger Q-angle is thought to be a predisposing factor for patellar dislocation, but previous literature has reported poor reliability and validity of clinically measured Q-Angle. In response to poor reliability, a new “Standard Q-Angle” (SQA) was developed by Merchant et al. (Merchant 2020) in an attempt to create a standardized and repeatable method of clinically measuring the Q-Angle. The SQA may be a practical, inexpensive, and valuable part of physical examinations to help clinicians decide if concomitant medializing osteotomy is indicated in patellar stabilization procedures. However, SQA has not yet been validated in patients with anatomic risk factors for recurrent patellar instability such as patella alta and trochlear dysplasia. Furthermore, while SQA has previously been demonstrated to have strong interrater reliability, it has never been shown to correlate with standardized measurements for a lateralized tibial tuberosity, such as the Tibial Tuberosity – Trochlear Grove (TT-TG) distance. Therefore, the purpose of our study was to determine the correlation between SQA and TT-TG distance in patients with recurrent patellar instability. We hypothesized that there would be a positive correlation between SQA and TT-TG distance. 1. Merchant AC, Fraiser R, Dragoo J, Fredericson M. A reliable Q angle measurement using a standardized protocol. Knee. 2020;27(3):934-939. Methods: Patients at a single institution treated by a single surgeon with recurrent patellar instability who had previously obtained a dynamic 4D CT scan were included in this study. Patients who had previous patellar stabilization procedures were excluded. The Standard Q-angle was measured as previously described by Merchant et al. (Merchant 2020). The patient was placed in the supine position with the knee extended. A long-arm goniometer was centered over the patella with the distal arm over the tibial tuberosity and the proximal arm extended up to the anterior superior iliac spine (ASIS). The examiner then centered the patella within the trochlear groove and the SQA was measured. A second examiner stood at foot of the patient’s bed to confirm positioning. Measurements were taken in the office, as well as in the operating room after the induction of general anesthesia. All measurements were performed by the senior author (***). Utilizing 4D CT scans, the TT-TG, Caton-Deschamps index (CDI), and lateral trochlear inclination (LTI) were measured as previously described. Patients whose CDIs were between 0.8 and 1.2 were considered to have normal patellar height. Patients whose LTIs were &gt;11° were considered to have normal LTI, which has been shown to have a sensitivity of 93% and a specificity 87% for detecting trochlear dysplasia. Mean and standard deviation values were calculated for patient demographic information, and correlation coefficients were calculated to compare SQA with TT-TG distance in both awake and anesthetized patients. The statistical software Stata was utilized for all analyses (StataCorp. 2021. Stata Statistical Software: Release 17. College Station, TX). Results: Fifty-seven patient knees were included in the study. The mean age was 22 years-old (±6 years). For awake patients, the correlation coefficient (R2) between SQA and TT-TG was -0.006 (Figure 1), and in anesthetized patients R2 = 0.093 (Figure 2). In the “normal patellar height” group, the R2 value was higher in the anesthetized group (R2 = 0.334) than the awake group (R2 = 0.239). In the normal lateral trochlear inclination group, there was also a greater R2 value in the anesthetized group (R2 = 0.403) than the awake group (R2 =0.093). The correlation between SQA and TT-TG was the strongest in anesthetized patients with both a CDI &lt; 1.2 and LTI &gt;11° (R2 = 0.635). Conclusions: There was a strong positive association between SQA and TT-TG in anesthetized patients with normal patellar height and a normal lateral trochlear inclination. However, in awake patients and patients with anatomic risk factors for recurrent patellar instability there was only a weak association between SQA and TT-TG. The SQA may be able to provide useful information, but only in selected cases. Therefore, it remains important to have objective radiographic measurements to characterize the position of the tibial tuberosity when planning patellar stabilization surgery.

Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study.

Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients. This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected. Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference). To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal.

Contour-aware network with class-wise convolutions for 3D abdominal multi-organ segmentation.

Accurate delineation of multiple organs is a critical process for various medical procedures, which could be operator-dependent and time-consuming. Existing organ segmentation methods, which were mainly inspired by natural image analysis techniques, might not fully exploit the traits of the multi-organ segmentation task and could not accurately segment the organs with various shapes and sizes simultaneously. In this work, the characteristics of multi-organ segmentation are considered: the global count, position and scale of organs are generally predictable, while their local shape and appearance are volatile. Thus, we supplement the region segmentation backbone with a contour localization task to increase the certainty along delicate boundaries. Meantime, each organ has exclusive anatomical traits, which motivates us to deal with class variability with class-wise convolutions to highlight organ-specific features and suppress irrelevant responses at different field-of-views. To validate our method with adequate amounts of patients and organs, we constructed a multi-center dataset, which contains 110 3D CT scans with 24,528 axial slices, and provided voxel-level manual segmentations of 14 abdominal organs, which adds up to 1,532 3D structures in total. Extensive ablation and visualization studies on it validate the effectiveness of the proposed method. Quantitative analysis shows that we achieve state-of-the-art performance for most abdominal organs, and obtain 3.63 mm 95% Hausdorff Distance and 83.32% Dice Similarity Coefficient on an average.

A prognostic classification of proximal humerus fractures: the cephalic extension staging.

Recent publications emphasized the role of dorsomedial metaphyseal extension of humeral head as predictor of ischemia after complex proximal humerus fractures (PHFs). We evaluated on preoperative 3D CT scan of PHFs the surface of this metaphyseal extension and its prognostic value on the occurrence of avascular necrosis (AVN). We followed a series of 25 fixations of complex PHF which had a preoperative 3D CT scan and measured the surface area of the posterior metaphyseal extension (PME) of the head. Using approximations, we calculated the ratio between the PME surface area (PMS) and the articular surface area of the head (HS). The PMS/HS ratio was analyzed against the risk of AVN. The measurement of the PMS/HS ratio emphasizes the significance of PME. The incidence of AVN is correlated with the magnitude of PME. Therefore, we include the PME as a fifth element in the characterization of complex PHFs and we propose a 4-stage prognostic classification based on the number of extensions of the humeral head. The head may have 3 extensions: posteromedial (PME), lesser tuberosity (LTE) and greater tuberosity (GTE). The risk of AVN decreases with the number of extensions of the head. Our study demonstrates a correlation between the occurrence of AVN and the size of PME in complex PHF cases. We propose a four-stage classification system to facilitate treatment decision-making between fixation and prosthesis.

OrthopedVR: clinical assessment and pre-operative planning of paediatric patients with lower limb rotational abnormalities in virtual reality

Rotational abnormalities in the lower limbs causing patellar mal-tracking negatively affect patients’ lives, particularly young patients (10–17 years old). Recent studies suggest that rotational abnormalities can increase degenerative effects on the joints of the lower limbs. Rotational abnormalities are diagnosed using 2D CT imaging and X-rays, and these data are then used by surgeons to make decisions during an operation. However, 3D representation of data is preferable in the examination of 3D structures, such as bones. This correlates with added benefits for medical judgement, pre-operative planning, and clinical training. Virtual reality can enable the transformation of standard clinical imaging examination methods (CT/MRI) into immersive examinations and pre-operative planning in 3D. We present a VR system (OrthopedVR) which allows orthopaedic surgeons to examine patients’ specific anatomy of the lower limbs in an immersive three-dimensional environment and to simulate the effect of potential surgical interventions such as corrective osteotomies in VR. In OrthopedVR, surgeons can perform corrective incisions and re-align segments into desired rotational angles. From the system evaluation performed by experienced surgeons we found that OrthopedVR provides a better understanding of lower limb alignment and rotational profiles in comparison with isolated 2D CT scans. In addition, it was demonstrated that using VR software improves pre-operative planning, surgical precision and post-operative outcomes for patients. Our study results indicate that our system can become a stepping stone into simulating corrective surgeries of the lower limbs, and suggest future improvements which will help adopt VR surgical planning into the clinical orthopaedic practice.

Polydopamine-coated biomimetic bone scaffolds loaded with exosomes promote osteogenic differentiation of BMSC and bone regeneration.

The repair of bone defects is ideally accomplished with bone tissue engineering. Recent studies have explored the possibility of functional modification of scaffolds in bone tissue engineering. We prepared an SF-CS-nHA (SCN) biomimetic bone scaffold and functionally modified the scaffold material by adding a polydopamine (PDA) coating loaded with exosomes (Exos) of marrow mesenchymal stem cells (BMSCs). The effects of the functional composite scaffold (SCN/PDA-Exo) on BMSC proliferation and osteogenic differentiation were investigated. Furthermore, the SCN/PDA-Exo scaffolds were implanted into animals to evaluate their effect on bone regeneration. SCN biomimetic scaffolds were prepared by a vacuum freeze-drying/chemical crosslinking method. A PDA-functionalized coating loaded with BMSC-Exos was added by the surface coating method. The physical and chemical properties of the functional composite scaffolds were detected by scanning electron microscopy (SEM), energy spectrum analysis and contact angle tests. Invitro, BMSCs were inoculated on different scaffolds, and the Exo internalization by BMSCs was detected by confocal microscopy. The BMSC proliferation activity and cell morphology were detected by SEM, CCK-8 assays and phalloidin staining. BMSC osteogenic differentiation was detected by immunofluorescence, alizarin red staining and qRT‒PCR. Invivo, the functional composite scaffold was implanted into a rabbit critical radial defect model. Bone repair was detected by 3D-CT scanning. HE staining, Masson staining, and immunohistochemistry were used to evaluate bone regeneration. Compared with the SCN scaffold, the SCN/PDA-Exo-functionalized composite scaffold had a larger average surface roughness and stronger hydrophilicity. Invitro, the Exos immobilized on the SCN/PDA-Exo scaffolds were internalized by BMSCs. The BMSC morphology, proliferation ability and osteogenic differentiation effect in the SCN/PDA-Exo group were significantly better than those in the other control groups (p<0.05). The effects of the SCN/PDA-Exo functional composite scaffold on bone defect repair and new bone formation were significantly better than those of the other control groups (p<0.05). In this study, we found that the SCN/PDA-Exo-functionalized composite scaffold promoted BMSC proliferation and osteogenic differentiation invitro and improved bone regeneration efficiency invivo. Therefore, combining Exos with biomimetic bone scaffolds by functional PDA coatings may be an effective strategy for functionally modifying biological scaffolds.

WITHDRAWN: Fractures partielles de la tête radiale : comment les analyser à partir des images scanner

BackgroundThe optimal treatment for different types of displaced partial articular radial head fractures is still debatable. Fractures involving the articulating portion of the radial head can be defined also as bi-articular and are often underestimated. Moreover, the complete loss of periosteal contact between fracture fragments is a marker of instability. Available classifications do not emphasize these aspects. The purpose of the present study is to describe two assessment methods to identify fractures involving the articulating portion of the radial head and complete loss of periosteal contact with the help of 2D-3D CT scan. The second purpose is to propose a classification of the displaced partial articular radial head fractures basing on these two assessment methods. HypothesisWe hypothesize that the proposed classification is reliable. Patients and methodsBy observing the position of the bicipital tuberosity with respect to the ulna in reference to the coronal plane in the 3D-CT scan and by observing the location of the fracture fragment in the 2D axial scan, it is possible to understand if a displaced partial articular fracture involves the articulating portion of the radial head. Also, it is possible to understand the presence or absence of a complete loss of periosteal contact between the two fracture fragments by observing the coronal and sagittal 2D CT scans. We identified 20 displaced partial articular radial head fractures on a series of 149 patients with radial head fractures. Following the above-described assessment methods, these 20 fractures were classified in three subgroups. Also, seven evaluators were asked to use these assessment methods to classify these 20 fractures in the three subgroups, in order to evaluate inter- and intra-observer agreement. ResultsEight fractures involved the non-articulating portion of the radial head with complete loss of periosteal contact, eight involved the non-articulating portion of the radial head without complete loss of periosteal contact, and four involved the articulating portion of the radial head with or without complete loss of periosteal contact. The kappa for intra-observer reliability ranged from 0.46 to 0.84. The average kappa for interobserver reliability was 0.570 (range: 0.526 to 0.676). The Kendall's coefficient for interobserver concordance was 0.673. DiscussionPrognostically, displaced partial fractures of the articulating portion of the radial head could differ from the other types, regardless of whether or not there is a complete loss of periosteal contact. Underestimating this fracture pattern can lead to poor results due to risk of forearm rotation blockage. Moreover, underestimating complete loss of periosteal contact in displaced partial fractures of the non-articulating portion of the radial head could lead to poor results. The described evaluation methods have moderate reliability, but can represent, along with other described methods, a good starting point to better understand and treat these insidious fractures. Level of evidenceIII; retrospective study.

A comparative analysis of the CP and CG using 2D and 3D visualisation approaches.

Investigations on the structural variations in the cribriform plate (CP), olfactory foramina and the Crista Galli showcase the benefits of using 3D imaging on smaller structures. These techniques reveal accurate details about bone morphology and density. Comparing different techniques, this project aims to examine the correlation between the CP, olfactory foramina, and Crista Galli. Computed tomography was used to translate and apply the findings acquired from the samples in radiographic studies on CPs for potential clinical significance. The findings show that the surface area measurements were significantly larger when using 3D imaging techniques in comparison with the 2D counterpart. Using 2D imaging, the maximum surface area of the CPs was 239.54mm2, however, paired 3D samples showed the maximum surface area was 355.51mm2. The findings show that Crista Galli's dimensions varied greatly, with length ranging from 15 to 26mm, height ranging from 5 to 18mm, and width ranging from 2 to 7mm. The 3D imaging allowed for surface area measurements on the Crista Galli, and the surface area ranged from 130 to 390mm2. When 3D imaging was used, significant correlations were found between the surface area of the CP and the length of the Crista Galli (p = 0.001). The findings show that measurements on the Crista Galli using 2D and 3D reconstructed radiographic imaging reflect similar ranges of dimensions to 3D imaging measurements. The findings also suggest that the Crista Galli may increase in length with the CP to support the latter and olfactory bulb during trauma which may be used by clinicians alongside 2D CT scans for optimal diagnosis.

Left atrial function after thoracoscopic left atrial appendage exclusion as standalone and as combined with epicardial atrial fibrillation ablation: echocardiographic findings at one- year follow up

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Left atrial appendage (LAA) is the most common source of thrombi in patients with atrial fibrillation (AF). The Totally Thoracoscopic (TT)-LAA exclusion with epicardial clip is an effective procedure, however the effects on left atrial (LA) function remain unknown. Purpose The aim of this study was to assess the impact of TT-LAA exclusion on the LA function in patients undergoing to standalone TT-LAA exclusion and patients received combined procedure, namely: TT-LAA exclusion and Thoracoscopic Epicardial Ablation (TEA). Methods 39 AF Patients underwent to TT-LAA exclusion with the clip. Indication to standalone TT-LAA exclusion was: high risk for ischemic stroke or contraindication to long-term anticoagulant therapy. All patients were screened preoperatively with 3D CT scan, transthoracic and trans-esophageal echocardiography. Intraoperative clip positioning and LAA exclusion were guided by trans-esophageal echo. To evaluate LA function, standard transthoracic echocardiography and 2D strain of LA were performed before surgery, at discharge (3-4 days after the procedure), at 3-month and at 1 year. Routine blood tests and BNP levels were also measured. Results The study enrolled 39 consecutive patients, 25 underwent to standalone TT-LAA exclusion (mean age 78.6 ± 5.7 years, 79% males), and 14 LAA exclusion during TEA (mean age 64.5 ± 8.2 years, 82% males). The mean CHA2DS2-VASc and HASBLED scores were 3.5 and 2.1 respectively. Baseline characteristics are summarized in Figure 1. There were no major complications during the procedure. At median follow-up of 13 months, 1 non cardiovascular death, 1 ischemic stroke and 4 cardiovascular hospitalizations occurred. At 2D strain of LA, the reservoir function decreased significantly after clip implantation and recovered at 3-months follow-up; at 1 year it remained stable. Furthermore, NT-proBNP increased significantly after LAA exclusion with a return to baseline after 3 months. Changes in E/A occurred at predischarge and did not persist at follow up. Echocardiographic findings are summarized in Figure 2. Patients with indication to TEA and LAA exclusion presented a lower LA volume and a lower strain value. Conclusion The main findings of this study can be summarized as follows: 1) The amputation of LAA is a safe procedure at long term follow up. 2) LAA amputation with the clip is associated with acute elevation of BNP levels the days after the procedure with return to baseline at 3 months and one year. 3) LAA amputation impairs the LA reservoir function after the procedure, with recovery after 3 months and remains preserved at one-year. This occurs either when LA strain is measured in sinus rhythm or in AF. 4) LAA exclusion results in a change in E/A that does not persist at three months follow-up and at 1 year. 5) Patients with indication to epicardial AF ablation and LAA exclusion present a lower LA volume with a lower strain value than patients undergoing standalone TT-LAA exclusion.