Automatic x-ray to CT registration using embedding reconstruction and lite cross-attention.

To establish whether preoperative computed tomographic (CT) findings in patients with acute cholecystitis were associated with conversion from laparoscopic to open cholecystectomy in patients with calculous acute cholecystitis. The study protocol was approved by the local institutional review board, and written informed consent was provided by all patients at enrollment. From 2008 to 2010, all patients admitted to a university medical center with acute calculous cholecystitis and for whom a preoperative contrast material-enhanced CT study was available were prospectively included. Cholecystectomy was always initiated laparoscopically. To identify risk factors for conversion specifically related to acute cholecystitis, CT studies were analyzed according to predefined criteria by two radiologists who were blinded to the patient's conversion status. Associations between conversion and radiologic findings were assessed by using univariate and multivariate logistic models. A total of 108 patients were analyzed (61 men, 47 women; median age, 58 years; age range, 17-88 years). Conversion occurred in 24 (22%) cases. On preoperative CT images, the absence of gallbladder wall enhancement was associated with the presence of gangrenous acute cholecystitis (sensitivity, 73%). The absence of gallbladder wall enhancement (58% and 40% for conversion and nonconversion, respectively; P = .02) and the presence of a gallstone in the gallbladder infundibulum (78% and 22% for conversion and nonconversion, respectively; P = .04) were associated with acute cholecystitis-related conversion in a multivariate analysis. Interobserver agreement for CT study interpretation was very good (median k value, 0.92; range, 0.76-1.00). The absence of gallbladder wall enhancement (associated with the presence of gangrenous acute cholecystitis) and the presence of a gallstone in the gallbladder infundibulum are associated with conversion from laparoscopic to open cholecystectomy.

For complex spinal cases, especially when robotic guidance is used, preoperative planning of pedicle screws can be helpful. Transfer of these preoperatively planned pedicle screws to intraoperative 3-dimensional imaging is challenging because of changes in anatomic alignment between preoperative supine and intraoperative prone imaging, especially when multiple levels are involved. In the spine, where each individual vertebra is subject to independent movement from adjacent level, rigid image fusion is confined to a single vertebra and can display fusion inaccuracies on adjacent levels. A novel elastic fusion algorithm is introduced to overcome these disadvantages. This study aimed to investigate image registration accuracy of preoperatively planned pedicle screws with an elastic fusion algorithm vs. rigid fusion for intraoperative placement with image-guided surgery. A total of 12 patients, were selected depending on the availability of a preoperative spinal computed tomography (CT) and an intraoperative AIRO CT scan (BrainLAB AG, Munich, Germany) of the same spinal region. To verify accuracy differences between rigid fusion and elastic fusion 76 bilateral screw trajectories were virtually defined in the preoperative CT image, and they were transferred via either rigid fusion or elastic fusion to the intraoperative CT scan. Accuracy of the transferred screws in the rigid and elastic fusion group was determined by measuring pedicle breaches on the intraoperative CT. In the rigid fusion group 1.3% of screws showed a breach of less than 2 mm, 9.2% showed breaches between 2 and 4 mm, and 18.4% of the screws showed an error above 4 mm. The elastic fusion group showed no breaches and provided high accuracy between preoperative and intraoperative screw placement. Elastic fusion provides high registration accuracy and represents a considerable step towards efficiency and safety in CT-based image-guided surgery. 3.

Abdominal wall hernias are common in the UK and many present in an emergent fashion. The widespread introduction of computed tomography (CT) imaging has transformed surgical practice but out of hours access can be limited by hospital resources and introduce delays. We investigated the influence of preoperative CT imaging in acutely symptomatic hernia and the association with surgical delay and risks of bowel ischemia. A retrospective analysis of patients undergoing emergency hernia surgery between 2013 and 2021 in a busy UK district general hospital. We evaluated the role of preoperative CT and its influence on timing of surgery, postoperative complications, critical care admission and hospital length of stay. Five hundred and five patients were studied. Of these, 191 had a preoperative CT scan. Sites of hernia included inguinal in 164 patients (33%); umbilical in 164 (33%); femoral in 69 (14%); incisional in 69 (14%); epigastric in 30 (6%) and Spigelian hernia 9 (2%). Preoperative CT imaging was associated with surgical delay (22.0h vs 13.0h, p < 0.001) and an increased need for bowel resection (12% vs 6%, p = 0.027). Delay in surgery was not associated with increased postoperative complications (5% vs 4%, p = 0.474) but was associated with increased critical care admission (11.0% vs 4.8%, p = 0.014). Preoperative CT scan for emergent hernias can delay often inevitable surgery and is associated with an increasing need for more complex, resectional surgery .

BackgroundIn Sweden, approximately 1300 patients are diagnosed with renal cell carcinoma (RCC) every year. The use of a computed tomography (CT) scan of the thoracic cavity in the preoperative work up of kidney cancer has increased in Sweden, and current national guidelines recommend that all patients, regardless of tumor size, should be evaluated this wayPurposeTo investigate the need for the preoperative routine to include a CT scan of the thoracic cavity when investigating renal masses 4 cm or smaller.Material and MethodsBetween 2017 and 2022, 496 patients at a university hospital and a regional hospital received treatment with curative intent for T1a tumors. Patient data and pathological findings were registered from patient records.ResultsMedian follow-up was 38 months. A total of 260 patients were examined with a preoperative CT scan of the thoracic cavity without pathology: 46 had not been scanned, 118 had indeterminate lesions, and metastasis was suspected in two cases. During follow-up, six patients had local relapse and none was diagnosed with lung metastasis. In no case did the preoperative CT of the thoracic cavity contribute to an early discovery of lung metastases.ConclusionOur conclusion is that a chest CT scan is superfluous in the preoperative work-up. The cost, and the time to treatment, could be reduced by precluding the chest CT in the preoperative work up for small renal tumors.

In geophysical survey industry, helicopter time domain electromagnetic systems (HTEM) are used widely due to their better spatial resolution and ability to conduct surveys in difficult geographical areas. However, these systems are limited in terms of the exploration depths achieved due to the constraints on the overall weight of the system that a helicopter can safely tow. There is a scope to develop a compact yet high power system that is light in weight, fast in response and able to control high current pulses to achieve deeper exploration depths. In this thesis, a new LabVIEW based power converter is proposed and implemented to achieve flexible and faster control of the TEM system. The current control is implemented with hysteresis current control logic and a constant ON-Time current control logic. Proposed topology and current control helps to achieve the targeted fall-time (100 μs) at the end of current pulse. An optimized LabVIEW code and constant ON-Time current control scheme is implemented to achieve sampling times as low as 2 μs. The comparison of experimental results with MATLAB simulation results validates the effectiveness of the control scheme. To reduce the switching power loss in the converter, the same hard switching power converter, working with constant ON-Time current control is modified to simulate a zero current switching scheme by designing the required resonant elements.

We hypothesized that preoperative computed tomography (CT) is a predictor of abdominal intervention for visceral malperfusion and stroke after emergent surgery for acute type A aortic dissection (AAAD). A total of 90 patients, mean (± SD [standard deviation]) age 62 (± 12) years, 76% males, undergoing emergent surgery for AAAD at our institution from May 2008 to August 2013 were included. All clinical data were collected prospectively and correlated to CT images. At initial presentation 9 (10%) patients showed preoperative focal neurologic deficit or coma, 10 patients (11%) complained of abdominal pain, and the logistic EuroSCORE was 44 (± 22). Hemiarch replacement was performed in 96%, total arch in 4%. The duration of hypothermic circulatory arrest (HCA) at 28°C bladder temperature was 26 (± 19) minutes. Cross-clamp time was 88 (± 39) minutes, and cardiopulmonary bypass (CPB) time 148 (± 49) minutes. Overall 30-day mortality was 13%. Moreover, 12 (13%) patients required postoperative abdominal interventions for suspected visceral malperfusion; stroke occurred in 25 (28%) patients. Logistic regression revealed that "dissection of the celiac trunk and/or the superior mesenteric artery" in preoperative CT images is a predictor of postoperative abdominal interventions for visceral malperfusion (p = 0.03), but preoperative abdominal pain is not similarly predictive. Postoperative stroke is best predicted by preoperative neurologic symptoms (p = 0.01), but not by supra-aortic vessel dissection in preoperative CT images. In patients undergoing surgery for AAAD, analysis of preoperative CT images allows identifying those with a high risk of postoperative abdominal intervention for visceral malperfusion. Postoperative stroke is best predicted by preoperative neurologic symptoms.

INTRODUCTION Oblique lumbar interbody fusion (OLIF) is a minimally-invasive technique that relies on a sufficient corridor anterior to the psoas and posterior to vascular structures.This intraoperative corridor is evaluated on preoperative computed tomography (CT) and/or magnetic resonance (MR) imaging to guide patient selection.Previous cadaveric studies and preoperative MR imaging analysis have examined this corridor to determine corridor variations along right- and left-sided approaches and among patient characteristics.This is the first study that directly evaluates the true intraoperative corridor in the lateral decubitus position based on intraoperative 3D imaging. METHODS We performed a retrospective evaluation identifying patients &gt; 18 yr old who had undergone an OLIF via a left-sided approach at 2 tertiary care centers from 2016 to 2018. Patients with scoliosis greater than 20 degrees, transitional anatomy, and psoas abnormalities were excluded.We recorded demographics and the intraoperative corridor defined by the distance between the left lateral border of the aorta or iliac vessels and anteromedial border of the psoas from L1-L2 through L4-5 disc spaces.This corridor was measured on supine, preoperative MR axial imaging and subsequent intraoperative 3D cone beam CT acquired in the right lateral decubitus position. RESULTS A total of 33 patients, 15 of whom were female, were included in this study.The average age was 65.4 and body mass index (BMI) was 31 kg/m2.There was a statistically significant increase (P &lt; .05) in the intraoperative corridor from supine to lateral decubitus positioning at all levels.The greatest increase in corridor size was noted at L1-2 (3.1 cm) and least at L4-5 (2.1 cm).There was no statistically significant difference between age, BMI, or gender in the preoperative versus intraoperative corridor. CONCLUSION This is the first study to provide objective evidence to support that lateral decubitus positioning increases the intraoperative corridor for anterior to the psoas techniques.This information should increase confidence with an anterior to the psoas approach if there is adequate corridor size on supine preoperative imaging evaluation.

The recent availability of standing computed tomography (CT) for equine paranasal sinus disease has enhanced diagnosis and enabled more targeted surgery compared to radiography and sinoscopy. To date, there have been no studies which have critically evaluated the benefit of preoperative CT versus radiography and sinoscopy on complications and outcome in horses undergoing sinus trephination. Retrospective study. A total of 229 equids. The medical records of equids (229) presented for sinusitis treated via trephination that had CT, radiography and/or sinoscopy at time of surgery between 2009 and 2022 were reviewed. Outcome and complications were evaluated for six different pre- and intraoperative imaging modalities. The six groups did not differ in demographics or disease category, though equids with less weight (p = .0179) and shorter disease duration (p = .0075) were more likely to have radiography and sinoscopy based surgical planning. Short-term postoperative complications occurred in 30.1% and were higher in groups using preoperative CT imaging (p = .01), with hemorrhage being the most common surgical complication. Following initial trephination surgery, 57.0% (127/223) of cases resolved and there was no difference between the imaging groups. Final resolution after follow-up medical or surgical treatment increased to 94.6% (211/223) and was not different between the imaging groups or between primary or secondary sinusitis. Additional nasal fenestrations to improve sinonasal drainage, maxillary septal bulla fenestrations and trephinations to treat nasal conchal bullae were made in the CT groups. CT provided additional diagnostic information and enabled different surgical approaches but did not improve resolution in this study population.

To improve estimation of cochlear implant (CI) insertion depth in postoperative skull x-rays using synthesized information from preoperative CT scans. Retrospective cohort. Tertiary referral center. Ten adult cochlear implant recipients with preoperative and postoperative temporal bone computed tomography (CT)scans and postoperative skull x-ray imaging. Postoperative x-rays and digitally reconstructed radiographs (DRR) from preoperative CTs were registered using 3D Slicer and MATLAB to enhance localization of the round window and modiolus. Angular insertion depth (AID) was estimated in unmodified and registration-enhanced x-rays and DRRs in the cochlear view. Linear insertion depth (LID) was estimated in registered images by two methods that localized the proximal CI electrode or segmented the cochlea. Ground truth assessments were made in postoperative CTs. Errors of insertion depth estimates were calculated relative to ground truth measurements and compared with paired t t ests. Pearson correlation coefficient was used to assess inter-rater reliability of two reviewer's measurements of AID in unmodified x-rays. In postoperative x-rays, AID estimation errors were similar with and without registration enhancement (-1.3 ± 20.7° and -4.8 ± 24.9°, respectively; mean ± SD; p = 0.6). AID estimation in unmodified x-rays demonstrated strong interrater agreement (ρ = 0.79, p < 0.05) and interrater differences (-15.0 ± 35.3°) comparable to estimate errors. Registering images allowed measurement of AID in the cochlear view with estimation errors of 14.6 ± 30.6° and measurement of LID, with estimate errors that were similar between proximal electrode localization and cochlear segmentation methods (-0.9 ± 2.2 mm and -2.1 ± 2.7 mm, respectively; p = 0.3). 2D-3D image registration allows measurement of AID in the cochlear view and LID using postoperative x-rays and preoperative CT imaging. The use of this technique may reduce the need for postimplantation CT studies to assess these metrics of CI electrode position. Further work is needed to improve the accuracy of AID assessment in the postoperative x-ray view with registered images compared with established methods.

Image-guided surgical navigation systems are widely regarded as the benchmark for computer-assisted surgical robotic platforms, yet a persistent challenge remains in addressing intraoperative image drift and mismatch. It can significantly impact the accuracy and precision of surgical procedures. Therefore, further research and development are necessary to mitigate this issue and enhance the overall performance of these advanced surgical platforms. The primary objective is to improve the precision of image guided puncture navigation systems by developing a computed tomography (CT) and structured light imaging (SLI) based navigation system. Furthermore, we also aim to quantifying and visualize intraoperative image drift and mismatch in real time and provide feedback to surgeons, ensuring that surgical procedures are executed with accuracy and reliability. A CT-SLI guided orthopedic navigation puncture system was developed. Polymer bandages are employed to pressurize, plasticize, immobilize and toughen the surface of a specimen for surgical operations. Preoperative CT images of the specimen are acquired, a 3D navigation map is reconstructed and a puncture path planned accordingly. During surgery, an SLI module captures and reconstructs the 3D surfaces of both the specimen and a guiding tube for the puncture needle. The SLI reconstructed 3D surface of the specimen is matched to the CT navigation map via two-step point cloud registrations, while the SLI reconstructed 3D surface of the guiding tube is fitted by a cylindrical model, which is in turn aligned with the planned puncture path. The proposed system has been tested and evaluated using 20 formalin-soaked lower limb cadaver specimens preserved at a local hospital. The proposed method achieved image registration RMS errors of 0.576 ± 0.146 mm and 0.407 ± 0.234 mm between preoperative CT and intraoperative SLI surface models and between preoperative and postoperative CT surface models. In addition, preoperative and postoperative specimen surface and skeletal drifts were 0.033 ± 0.272 mm and 0.235 ± 0.197 mm respectively. The results indicate that the proposed method is effective in reducing intraoperative image drift and mismatch. The system also visualizes intraoperative image drift and mismatch, and provides real time visual feedback to surgeons.

Unrecognized or untreated injury in patients with ankylosing spondylitis (AS) may develop anterior column spinal pseudoarthrosis with an open wedge bone defect. The methods of surgical treatment are controversial. Combined anterior and posterior stabilizations or posterior instrumentation with osteoclasis are beneficial as shown in an existing literature review. A 36-year-old Asian man with AS sustained a motor vehicle accident 2 years before presentation. At that time, his immediate magnetic resonance imaging scan demonstrated T10-T11 bone edema and granulation tissue formation with fluid accumulation in T10-T11 disc space. He opted for conservative treatment. His back pain was then exacerbated 2 years after the accident, and he underwent three-dimensional (3D) computed tomography (CT) scan revealing a severe pseudoarthrosis with sclerotic margins across the T10 caudal end vertebra to the T11 upper end plate, with a maximal fracture gap of 15 mm. Spinal cord compression was not present. After selecting for an appropriate cage size with the aid of the preoperative 3D CT images, we used a single posterior approach to apply pedicle screws, removed pseudoarthrotic granulation tissue through an intertransverse posterior lateral approach without entering the spinal canal, and inserted a transforaminal lumbar interbody fusion (TLIF) cage with bone graft. There was radiographic evidence of spinal fusion at the 9-month follow-up, and the patient had resumed all normal daily activities. The authors found that a less invasive single posterior surgical approach using a TLIF cage and pedicle screws could be applied to AS patients with combined thoracic pseudoarthrosis and an anterior column defect. Using a TLIF cage may provide circumferential stability immediately, bone graft fusion, and sagittal plane correction simultaneously. An appropriate cage size and placement selected with preoperative 3D CT images are the keys to success.

Hepatocellular carcinoma (HCC) is characterized by high postoperative recurrence rates, and predicting early recurrence is crucial for improving clinical outcomes, yet remains challenging. Both preoperative computed tomography (CT) imaging radiomic features and serum biomarkers related to microvascular infiltration are important indicators of HCC prognosis. This study aimed to develop a nomogram model incorporating both preoperative CT radiomic features and serum biomarkers associated with microvascular infiltration to predict early postoperative recurrence in HCC patients. The study included 156 HCC patients who underwent radical surgery at the Tumor Hospital Affiliated to Nantong University between January 2021 and January 2022. Preoperative CT imaging data were obtained for each patient, and radiomic features were extracted using the 3D Slicer software. Preoperative serum biomarkers related to microvascular invasion were collected, including alpha-fetoprotein (AFP), vascular endothelial growth factor A (VEGF-A), Speckled Protein 100 (SP100), and the Fibrosis-4 (FIB-4) index levels. Postoperative follow-up was conducted for 2 years, during which recurrence data were collected. The radiomics score was generated through dimensionality reduction and least absolute shrinkage and selection operator (LASSO) regression analysis. Univariate and logistic regression analyses were used to identify independent risk factors for early postoperative recurrence of HCC. The nomogram model was constructed using R language, and its predictive performance was evaluated using receiver operating characteristic curves, calibration curves, and decision curve analysis curves. Among the 156 patients, 60 experienced early recurrence, while 96 did not. Feature reduction through LASSO regression identified 10 optimal features from the venous phase and 4 optimal features from the arterial phase, leading to the development of a radiomics score formula. The early recurrence group had significantly higher radiomics scores than the non-early recurrence group [-1.35 (-2.29, 1.21) vs. 0.94 (-0.40, 1.87), P<0.001]. Logistic multivariate regression analysis identified lesion number, Edmondson grade, AFP and VEGF-A levels, and radiomics score as independent risk factors for early postoperative recurrence of HCC (P<0.05). The nomogram model demonstrated high predictive performance with area under the curve (AUC) values of 0.9265 and 0.9255 in the training and internal test sets, respectively. The model demonstrated good net benefit across a threshold range of 0.01-75%, effectively identifying high-risk patients for early postoperative recurrence. The nomogram model based on preoperative serum biomarkers related to microvascular infiltration and CT radiomic features demonstrated high predictive performance for early postoperative recurrence of HCC. However, further studies, including external validation, are needed to establish the model's generalizability and clinical applicability.

Three-dimensional digitizer (neuronavigator): New equipment for computed tomography-guided stereotaxic surgery

To describe a novel technique using preoperative computed tomography (CT) to plan clamp tine placement along the trans-syndesmotic axis (TSA). We hypothesized that preoperative CT imaging provides a reliable template on which to plan optimal clamp tine positioning along the TSA, reducing malreduction rates compared with other described techniques. CT images of 48 cadaveric through-knee specimens were obtained, and the TSA was measured as well as the optimal position of the medial clamp tine. The syndesmosis was then fully destabilized. Indirect clamp reductions were performed with the medial clamp tine placed at positions 10 degrees anterior to the TSA, along the TSA, and at both 10 and 20 degrees posterior to the TSA. The specimens were then separately reduced using manual digital pressure and palpation alone. CT was performed after each clamp and manual reduction. On average, reduction clamp tines were within 3 ± 2 degrees of the desired angle and within 5% ± 4% of the templated location along the tibial line for all clamp reduction attempts. Palpation and direct visualization produced the overall lowest malreduction rates in all measurements: 4.9% and 3.0%, respectively. Off-axis clamping 10 degrees anterior or 20 degrees posterior to the patient-specific TSA demonstrated an increased overall malreduction rate: 15.8% and 11.3%, respectively. Significantly more over-compression occurred when a reduction clamp was used versus manual digital reduction alone (8.6% vs. 0%). Reduction clamp placement directly along an optimal clamping vector can be facilitated by preoperative CT measurements of the uninjured ankle. However, even in this setting, the use of reduction clamps increases the risk for syndesmotic malreduction and over-compression compared with manual digital reduction or direct visualization.

Background Characteristics and risk factors of lymph node metastasis (LNM) in esophageal squamous cell carcinoma (ESCC) patients with preoperative computed tomography (CT)-negative lymph nodes are not well elucidated. This study aimed to identify the characteristics and risk factors of LNM in ESCC patients with preoperative CT-negative lymph nodes. Methods We conducted a retrospective analysis of consecutive ESCC patients who had preoperative CT-negative lymph nodes and received esophagectomies between August 2013 and July 2016. Lymph node with a short-axis diameter ≦10 mm on preoperative CT image was considered as CT-negative lymph node. Eligible patients included those: aged 18∼80, without neoadjuvant therapy, without other malignant tumor history, without distant metastasis, without multiple esophageal lesions, tumor locating in the thoracic esophagus, receiving McKeown esophagectomy, undergoing R0 resection, having number of lymph nodes resection≧15, pathological staging as T1a-4aN0–3. Univariate and multivariate logistic regression analyses were used to identify risk factors of LNM. Results Among 243 ESCC patients identified, 137 had LNM (56.4%). The median number of lymph nodes dissected and LNM were 24 (range 15–79) and 2 (range 1–14), respectively. The rates of LNM of the upper, middle and lower thoracic ESCC were 50.0%, 59.3% and 55.1%, respectively. The rates of LNM with the maximal short-axis diameter of lymph node on preoperative CT of ≦5 mm, 6 mm, 7 mm, 8 mm, 9 mm and 10 mm were 57.4%, 42.9%, 47.4%, 31.8%, 73.9% and 70.8%, respectively (P = 0.034). Univariate analysis showed that age (P = 0.041), maximal short-axis diameter of lymph node on CT (P = 0.034), cervical lymph node dissection (P = 0.031), lymphovascular invasion (P &lt; 0.001) and perineural invasion (P = 0.017) were associated with LNM. Multivariate analysis revealed that cervical lymph node dissection (P = 0.018), lymphovascular invasion (P = 0.007) and perineural invasion (P = 0.025) were independent risk factors of LNM. Conclusion Our study showed that the rates of LNM were also high in ESCC patients with preoperative CT-negative lymph nodes. Standard lymph node dissection is necessary for these patients. Cervical lymph node dissection, lymphovascular invasion and perineural invasion are independent risk factors of LNM in ESCC patients with preoperative CT-negative lymph nodes. Disclosure All authors have declared no conflicts of interest.