Diagnostic CT Scan Research Articles

ANTROCHOANAL POLYP OF MAXILLARY SINUS IN ADULT – A CASE REPORT

ABSTRACT Antrochoanal polyp also called Killian Polyp is an inflammatory polyp, which arises from within the maxillary sinus, and prolapses in to the nasal cavity through the accessory ostium of the maxillary sinus. This polyp grows backwards towards the posterior choana. It is a unilateral benign lesion common in children and rare among adults. Antrochoanal polyps are diagnosed clinically with diagnostic nasal endoscopy and CT scan of paranasal sinus helps in analyzing the extent of lesion and in ruling out other differential diagnosis of a unilateral nasal mass. The gold standard modality of treatment is functional endoscopic sinus surgery with complete removal of the polyp by dissecting out all the attachments of the polyp from within the maxillary sinus and widening of the obstructed ostium. The typical histological features are characterized by presence of cystic component, infiltration of inflammatory cells and edema. The choanal portion shows presence of fibrosis and squamous metaplasia . This is a case report of an adult patient with antrochoanal polyp. Key words-Antrochoanal polyp, Unilateral, Adult.

A Fast-Track Surgery Programme Leads to Timelier Treatment and Higher Resection Rates in Pancreatic Cancer

Introduction: The aim of this study was to perform a propensity-matched comparison of patients with pancreatic cancer undergoing surgery, with and without biliary stenting, to examine perioperative outcomes and to perform an intention to treat analysis to evaluate long-term survival between the two groups. Methods: This was an observational study of a cohort of consecutive patients presenting with obstructive jaundice and undergoing pancreatoduodenectomy for pancreatic and periampullary malignancies between November 2015 and May 2019. Results: In this retrospective study of 216 consecutive operable patients, 70 followed the fast-track (FT) pathway and 146 had pre-operative biliary drainage (PBD). All patients in the fast-track group and 122 out of 146 in the PBD group proceeded to surgery (100% and 83.6% respectively, p=0.001). Interval time from diagnostic CT scan to surgery and from MDT decision to treat to surgery was much shorter in the FT group (median range) 8 vs 43 days p<0.001 and 3 vs 36 days p<0.001 respectively) as was the overall time from diagnostic CT to adjuvant treatment (88 vs 121 days p<0.001). Postoperative outcomes including in-hospital stay, number and grading of complications, readmission rate and mortality rates were comparable in the two groups. There was no difference in survival between the two groups. Conclusion: These data strengthen the existing evidence that, for a person with pancreatic cancer who is proceeding to surgery, the best approach is to avoid pre-operative biliary drainage. The optimal comparison to the neoadjuvant approach is upfront fast-track surgery without biliary drainage followed by adjuvant therapy.

Artificial Intelligence-Guided Prediction of Dental Doses Before Planning of Radiation Therapy for Oropharyngeal Cancer: Technical Development and Initial Feasibility of Implementation

PurposeThe aim was to develop a novel artificial intelligence (AI)–guided clinical decision support system, to predict radiation doses to subsites of the mandible using diagnostic computed tomography scans acquired before any planning of head and neck radiation therapy (RT). Methods and MaterialsA dose classifier was trained using RT plans from 86 patients with oropharyngeal cancer; the test set consisted of an additional 20 plans. The classifier was trained to predict whether mandible subsites would receive a mean dose >50 Gy. The AI predictions were prospectively evaluated and compared with those of a specialist head and neck radiation oncologist for 9 patients. Positive predictive value (PPV), negative predictive value (NPV), Pearson correlation coefficient, and Lin concordance correlation coefficient were calculated to compare the AI predictions to those of the physician. ResultsIn the test data set, the AI predictions had a PPV of 0.95 and NPV of 0.88. For 9 patients evaluated prospectively, there was a strong correlation between the predictions of the AI algorithm and physician (P = .72, P < .001). Comparing the AI algorithm versus the physician, the PPVs were 0.82 versus 0.25, and the NPVs were 0.94 versus 1.0, respectively. Concordance between physician estimates and final planned doses was 0.62; this was 0.71 between AI-based estimates and final planned doses. ConclusionAI-guided decision support increased precision and accuracy of pre-RT dental dose estimates.

O-P02 A fast-track surgery programme leads to timelier treatment and higher resection rates in pancreatic cancer

Abstract Background Pancreatic cancer is currently the fourth most common cause of cancer-related mortality in the economically developed world and is set to become the second most common cause of cancer-related mortality within the next few years. NICE guidance makes a strong recommendation to offer up-front surgery to people with resectable pancreatic cancer, without preoperative biliary drainage, if sufficiently fit for surgery. The aim of this study was to perform a propensity-matched comparison of patients with pancreatic cancer undergoing surgery, with and without biliary stenting, to examine perioperative outcomes and to perform an intention to treat analysis to evaluate long-term survival between the two groups. Methods This was an observational study of a cohort of consecutive patients presenting with obstructive jaundice and undergoing pancreatoduodenectomy for pancreatic and periampullary malignancies between November 2015 and May 2019. Data related to patient and tumour characteristics, biliary drainage, surgery and histopathology were gathered and analysed from a prospectively maintained electronic database. Post-operative complications were defined and graded according to the definitions of the International Study Group on Pancreatic Surgery (ISGPS) and the Clavien-Dindo system. Data related to adjuvant treatment, disease recurrence and overall survival were also analysed. Results In this retrospective study of 216 consecutive operable patients, 70 followed the fast-track (FT) pathway and 146 had pre-operative biliary drainage (PBD). All 70 patients in the fast-track group and 122 out of 146 in the PBD group proceeded to surgery (100% and 83.6% respectively, p = 0.001). Interval time from diagnostic CT scan to surgery and from MDT decision to treat to surgery was much shorter in the FT group (median range) 8 vs 43 days p &amp;lt; 0.001 and 3 vs 36 days p &amp;lt; 0.001 respectively) as was the overall time from diagnostic CT to adjuvant treatment (88 vs 121 days p &amp;lt; 0.001). Postoperative outcomes including in-hospital stay, number and grading of complications, readmission rate and mortality rates were comparable in the two groups. There was no difference in survival between the two groups. Conclusions These data strengthen the existing evidence that, for a person with pancreatic cancer who is proceeding to surgery, the best approach is to avoid pre-operative biliary drainage. The optimal comparison to the neoadjuvant approach is upfront fast-track surgery without biliary drainage followed by adjuvant therapy.

Potential risks of cardiovascular and cerebrovascular disease and cancer due to cumulative doses received from diagnostic CT scans?

Potential risks from radiation exposure on the development of cardiovascular and cerebrovascular disease are indicated by epidemiological studies. Medical exposures give the largest dose to the population from artificial sources, with cumulative doses from multiple CT scans being significant. Data on doses from scans performed on 12 CT scanners in three hospitals over a period of 5½ years, derived using RadimetricsTM software, have been reviewed for 105 757 patients. Data have been downloaded for heart, brain, thyroid, and effective doses, and cumulative doses analysed using ExcelTM spreadsheets. 2.4% of patients having body CT scans received cumulative doses to the heart over 100 mSv, 9% of whom were under 50 years. 9.6% of patients having head CT scans received cumulative doses to the brain over 100 mSv with 0.08% over 500 mSv from whom 41% were under 50 years, but only 1.3% of patients scanned had thyroid/carotid artery doses over 100 mSv. An approximate evaluation of potential risks from exposures of the heart above 100 mSv and brain over 500 mSv for patients under 60 years would suggest that at most only one patient would demonstrate any excess risk from vascular disease resulting from the exposures. 0.67% of patients scanned received effective doses over 100 mSv, in line with results from European studies, with 8.4% being under 50 years. The application of age and sex specific risk coefficients relating to excess cancer incidence suggests that two or three patients with effective doses over 100 mSv and five patients with effective doses between 50 and 100 mSv, from those examined, might develop cancer as a result of exposure. However, this will be an overestimate, since it does not take patients’ health into account. Exposure management software can aid in evaluating cumulative doses and identifying individual patients receiving substantial doses from repetitive imaging.

EVALUATION OF DIAGNOSTICNASAL ENDOSCOPY AND CTSCAN IN VARIOUS SINONASAL DISEASES

Objective:To evaluate role of Diagnostic Nasal Endoscopy and CT scan in various Sinonasaldiseases with regards to diagnosis and surgical intervention. Patient and methods:This prospective study was carried out in Department of ENT, A.N.M.M.C.H., Gaya on 200 patients with clinical evidence of sinonasal disease who had presented between March 2016 to February 2019. All patients were evaluated with DNE using 0 degree 4mm endoscope and CT scan with 3 mm coronal cuts. Result: Female patients(56%) were more as compared to male(44%) with majority between 21 - 40 yrs. Most common finding on Diagnostic Nasal Endoscopy(DNE) was mucopurulent discharge in middle meatuswhile on CT Scan was maxillary sinusitis(60%). Sinonasal polyp detection was better with DNE.CT has better detection rate of anatomical variation of osteomeatal complex. Conclusion : DNE has become initial tool for diagnosis as it is cost effective and office based procedure. In patients where surgical intervention is required, CT scan has advantage as it provides detailed understanding of anatomical variations. So bothDNE and CT scan should be used in collaborative fashion. Source Of Support:Patients of A.N.M.C.H., Gaya. Conflict Of Interest:None.

Diagnostic Accuracy of CT Scans in Blunt Abdomical Trauma

Background and Aim: Blunt abdominal trauma may lead to a serious situation that necessitates prompt diagnosis and treatment. The intra-abdominal injury effective diagnosis is difficult in patient’s management in such cases. The present study aims to evaluate the diagnostic accuracy of computed tomography scans in active internal bleeding following abdominal trauma. Materials and Methods: This cross-sectional study was carried out on 84 blunt abdominal trauma patients in the Department of Radiology Hayatabad Medical Complex, Peshawar for duration of six months from January 2021 to June 2021. All the patients with no clinical manifestations underwent diagnostic CT scans. Those who had a positive CT scan underwent laparotomy. The remaining patients were monitored for 24 hours and were discharged in case of no serious issues. Demographic details, patient information, trauma mechanism, CT scan indications, and findings, and laparotomy results were recorded. Regarding injured organs, specificity, sensitivity, and diagnostic accuracy of CT scans were determined. For individual cases, CT scans specificity, sensitivity, and accuracy were calculated. SPSS version 20 was used for data analysis. Results: This study included 84 patients, out of which 73 (86.9%) were male and 11(13.1%) were female. Patients aged 20-40 years were more prevalent 47 (56%), followed by those aged over 40 years were 20 (23.8%) and 10 to 19 years old were 17 (20.2%). Liver and spleen injuries had the highest CT scan sensitivity of 87.5% and 96.7% respectively. On the other hand, The CT scan's specificity was high in the injured kidneys (94%) and retroperitoneal hematoma 97.3% compared to other organ’s injuries. The diagnostic accuracy of CT scans in the identification of liver, kidney injuries, spleen, and retroperitoneal hematoma injuries was 93.7%, 92.3%, 96.2%, and 92.3% respectively. Conclusion: Our study found that CT scans are capable of detecting a wide range of injuries. CT scans are exceptionally valuable for assessing blunt abdominal injuries with active internal bleeding patients Furthermore, CT investigation is quick and extensively accessible. CT can produce high-resolution images with MPR and scanning protocol. Keywords: Diagnostic Accuracy; Abdominal Trauma Injuries, Computed Tomography (CT)

EP.WE.613A multi-centre review of the management of acute appendicitis during the COVID-19 pandemic

AimAcute appendicitis is a common surgical presentation and is historically a clinical diagnosis; gold-standard treatment is appendicectomy. Due to anticipated increased demand on in-patient beds during the COVID-19 pandemic there was increased emphasis on conservative management of acute appendicitis. Our aim is to review these changes and determine the representation rate following conservative management.MethodsPatients with acute appendicitis were identified from daily referral lists across two trusts. Data was collected using electronic care records. A control group (106 patients) was identified from 3 months preceding the pandemic.ResultsIn the pandemic group, 213 patients had acute appendicitis; 47% were managed conservatively, compared to 8% of the control group. Overall, during the pandemic 44% of patients had a CT-confirmed diagnosis (compared to 48% of control group); the two trusts’ results varied showing 75% and 30% (compared to 46% and 51% respectively in the control group). Of those treated conservatively only 3% represented to hospital and required admission.ConclusionSignificantly more patients were treated conservatively during the COVID-19 pandemic. The larger number of patients managed as acute appendicitis in the pandemic group may represent over-diagnosis due to the decision to conservatively manage these patients and account for diagnostic uncertainty. Increased access to early diagnostic CT scans facilitated early decisions regarding definitive management. Variation in access to radiology both during and before the pandemic may account for the difference in use of CT scans. Low rates of readmission to hospital following conservative management of acute appendicitis have been observed to date.

A Crowdsourcing Challenge for the Development of Artificial Intelligence Algorithms for Automated Identification and Delineation of Pancreatic Cancer Primary Tumors

To develop a crowdsourced artificial intelligence computational algorithm to accurately identify and delineate pancreatic cancer (PC) primary tumors and major peripancreatic vessels on high-resolution CT images.After IRB approval, a well-curated data set of 243 diagnostic pancreatic-protocol high-resolution CT scans of patients diagnosed with PC was prepared. A data science marathon competition was then hosted online by a third-party company between December 2020 and January 2021. The full data set was randomly partitioned into training, validation and hold-out (scoring) data sets. Contestants were provided a training dataset containing [de-identified files from a high-resolution IV contrast-enhanced CT DICOM image set; de-identified DICOM metadata; de-identified RT structure set file with contours of the tumor and superior mesenteric artery (SMA), celiac axis/common hepatic artery continuum (CA/CHA), and superior mesenteric vein/portal vein continuum (SMV/PV)], along with a smaller validation data set with CT scans without contours to test their trained algorithms. Provisional scores were assigned using the validation data set throughout the competition. Final scoring of submitted algorithms was based on the performance of the algorithms on a hold-out data set (unavailable for the contestants), matched against the expected ground truth data using an F1 scoring metric [2 * precision * recall / (precision + recall)], in which precision = TP / (TP + FP), and recall = TP / (TP + FN). TP is the area (measured in pixels) of the overlap of expected (ground truth delineation) and extracted (submitted algorithm) regions, FP is the area extracted but which does not belong to expected regions, FN is the area of the expected regions that is not covered by extracted regions. The above was calculated separately for the 4 structure types (tumor, SMA, CA/CHA, and SMV/PV), with a weighted average of the four F1 values, where the weight of the tumor was 7, and the weight of each of the vessels was 1. A final average for each contestant was scaled up to 0-100 range.In total, 337 algorithm solutions from 23 competitors were submitted. The winning algorithm achieved an average F1 score of 70.2. The F1 score ranged from 69.8 to 66.7 between the 2nd and 5th best solutions. The winning solution used a 3D-UNet model to develop a 3D semantic segmentation approach that was found to be significantly accurate on tumor and vessel delineation. A comparison between the winning solution and an ensemble between the 2nd to 5th place solutions showed that in 82% of cases, both the winning and the ensembled solution succeeded in achieving an F1 score > 60.A crowdsourced innovation challenge was successfully employed to generate artificial intelligence algorithms capable of accurately delineating pancreatic cancer on a diagnostic CT scan.

Feasibility of Implementing Thoracic Radiation Therapy for COVID-19 Pneumonia

Purpose/Objective(s)The value of low dose whole thoracic radiation therapy (LD-WTRT) for SARS-CoV-2 (COVID-19) pneumonia is unknown. Should ongoing clinical trials demonstrate LD-WTRT proves effective for COVID-19 pneumonia recovery, widespread rapid implementation will be helpful globally. Our aim was to outline a pragmatic process that could be implemented successfully in a community hospital.Materials/MethodsTo identify appropriate patients admitted to the hospital with COVID-19 pneumonia, we worked with Nursing Informatics to screen all currently admitted COVID+ patients requiring oxygen supplementation. For patients meeting criteria of the PreVent protocol per chart review, radiation oncologists contacted the hospitalist physician for telehealth consultation with the patient to discuss single dose LD-WTRT. After a patient had confirmed interest in treatment, at time of physical exam, we obtained consent and digitally transferred the signed consent form via secure text to avoid contaminated forms. Chest radiographs were used to estimate AP/PA field size and separation at the carina; diagnostic chest CT data was imported into the treatment planning system for field size and MU calculation before patient arrival, without using the department's CT simulator. Inpatient Nursing transported patients for treatment after clinic hours on a route pre-approved by Infection Control. The treating radiation oncologist and one ‘hot’ radiation therapist assisted with patient set-up supine or prone on the linear accelerator couch. After decontamination, the physician and a ‘cold’ therapist confirmed field size and MU calculations to prepare for treatment delivery. Nursing monitored patient O2 saturation and stayed gowned with the ‘hot’ therapist. After patient departure, Radiation Oncology contacted Facilities for decontamination of the vault before treating cancer patients the following day.ResultsFor the first treated patient, telehealth consultation lasted 40 minutes. In-person exam, evaluation and consent took 60 minutes, of which 30 were for the protocol-required consent form. With the diagnostic CT scan, field design and MU calculations took 20 minutes. Patient arrival to departure took 40 minutes. Once the patient was positioned on the couch, localization, MU confirmation and entry and treatment delivery took 16 minutes.ConclusionWe have developed a process to efficiently provide LD-WTRT for patients with COVID pneumonia that minimizes staff exposure, departmental equipment, and room contamination. Should clinical trials indicate that LD-WTRT helps treat COVID pneumonia patients, this process can work in most hospital-based radiation oncology departments to provide LD-WTRT efficiently and safely. Staff and cancer patient vaccination will further lower the risks of implementing LD-WTRT but is not necessary with careful planning and consultation with infection control.

Cardiac Motion and its Impact on Target Coverage During SBRT for Refractory Ventricular Tachycardia

<h3>Purpose/Objective(s)</h3> Refractory ventricular tachycardia (VT) is a common cause of death and morbidity in the heart failure population. Stereotactic body radiation therapy (SBRT) is a new and promising approach to treating VT, but there are practical concerns about SBRT delivery to the heart, which undergoes motion from both cardiac and respiratory cycles. In this study, we investigate motion magnitudes from both cycles and their impact on treatment margins and target coverage for VT SBRT. <h3>Materials/Methods</h3> Twenty-one patients were treated with SBRT for VT at our institution between April 2018 and December 2020 under an IRB-approved registry protocol. All patients had respiratory-correlated 4DCT for treatment planning and 7 patients had diagnostic cardiac-gated CT scans taken less than two weeks prior to treatment. Target structures were delineated on free-breathing CT and transferred to respiratory average (RAVG) CT via rigid registration. Dose was initially calculated on the RAVG per current institutional standard of care. For this retrospective study, deformable image registration (DIR) was applied between RAVG and the cardiac average CT (CAVG), systolic, and diastolic CTs from the cardiac dataset. Target contours were transferred to the registration target image. Motion magnitudes and distributions from the deformation vector fields were analyzed. Internal target volumes (ITVs) were created on the respiratory average images for quantitative analysis of target motion and coverage changes. From these 7 patients, 11 distinct target volumes were treated, with 8 being epicardial and 3 endocardial. Motion and dosimetry for all 11 targets were analyzed separately. <h3>Results</h3> The average (SD) target shift magnitudes (in mm) from the RAVG to CAVG CTs were 2.0 ± 1.0, 2.0 ± 1.3, and 4.0 ± 2.0 in the left-right (LR), anterior/posterior (AP), and superior/inferior (SI) directions. Endocardial targets had greater motion magnitude than epicardial targets, with mean shifts of 2.2 ± 1.0, 2.3 ± 1.9, and 4.2 ± 2.4 in the LR, AP, and SI directions versus 1.4 ± 0.9, 1.3 ± 0.8, and 3.6 ± 0.5. Cardiac cycle motion showed more variability for epicardial targets with shifts of 1.4 ± 2.5, 2.4 ± 3.0, and 2.5 ± 3.7 in the LR, AP and SI directions, versus 2.0 ± 0.6, 2.1 ± 0.8, and 1.6 ± 0.7 for endocardial targets. Creation of motion encompassing ITVs led to an average target size increase of 100% (25 cm³). V95 for initial target volumes was 99.9 ± 0.4% while the average V95 for ITVs was 84.1 ± 15.6%. Similarly, D95 for the target dropped from 108.2 ± 5.7% to 75.3 ± 28.4%. <h3>Conclusion</h3> In this cohort of patients undergoing SBRT for VT, cardiac shifts were location-dependent and were largest in the SI direction. These shifts typically exceeded the 1-5 mm margins used for SBRT treatment planning and ITV generation to encompass all target motion led to a doubling in target size. Our data suggest that cardiac-gated delivery may be helpful to minimize treatment volumes and spare cardiac tissue.

236 Omental Fat Torsion Masquerading Clinically as Acute Appendicitis in a Young Male Patient: A Rare Aetiology of Acute Abdomen and The Value of Diagnostic Laparoscopy

Abstract Acute abdominal pain is a common surgical presentation and acute appendicitis remains the top differential for most young adults. Omental fat torsion has emerged as a rare aetiology of an acute surgical abdomen in the younger population that closely mimics acute appendicitis in its clinical presentation. Preoperative diagnosis is extremely challenging in this age group due to the rarity of the condition and the non-specific nature of its clinical and laboratory findings, and hence most reported diagnoses were made intra-operatively. We report a case of omental fat torsion in a 22-year-old male who presented with clinical features that were highly suggestive of acute appendicitis. However, the diagnostic laparoscopy revealed a normally looking appendix and terminal ileum, with the presence of a twisted segment of the greater omentum in the right lumbar region. A laparoscopic omentectomy and a prophylactic appendectomy to prevent furture acute appendicitis were performed with an uneventful postoperative recovery. Histology confirmed omental fat infarction and a normal appendix. This reported case highlights a rare cause of right iliac fossa pain and demonstrates the value of diagnostic laparoscopy in the context of clinically suspected acute appendicitis in younger male patients. Diagnostic imaging was not deemed necessary in our patient given the strong clinical suspicion of acute appendicitis. Prompt laparoscopy led to definitive diagnosis as well as treatment and avoided the radiation exposure necessitated during a diagnostic computed tomography scan.

Therapeutic window for obtaining favorable remodeling after thoracic endovascular aortic repair of type B aortic dissection

ObjectiveThe purpose of the present study was to determine the most appropriate timing for thoracic endovascular aortic repair (TEVAR) of type B aortic dissection (TBAD) in terms of remodeling of the aorta. MethodsA total of 41 patients who had undergone TEVAR for the treatment of aortic dissection were included in the present study. The patients were divided into two groups: those who had undergone TEVAR in the acute or subacute phase (group A) and those who had undergone TEVAR in the chronic phase (group B). The indications for TEVAR as the treatment of TBAD were the presence of aortic rupture or malperfusion of the aortic branches, a maximum aortic diameter of ≥40 mm on the initial diagnostic computed tomography scan, and/or expansion of the aorta of ≥5 mm within 3 months for acute and subacute TBAD. The indication was a maximum aortic diameter of ≥50 mm or expansion of the aorta of ≥5 mm within 1 year for chronic TBAD. The diameters of the aorta, true lumen, and false lumen were measured at the level of the most dilated part of the descending aorta (level M) and at the diaphragm (level D) on the computed tomography scan obtained before TEVAR and at the 2-year follow-up examination. ResultsThe median interval between TEVAR and the onset of TBAD was 0.2 month (interquartile range, 0.03-0.7 month) in group A (n = 21) and 32 months (interquartile range, 4.7-35.2 months) in group B (n = 20). Except for the aortic diameter at level D in group B, favorable remodeling was obtained at both levels in both groups. The diameter change ratio of the aorta at level D was significantly greater in group A than in group B (P = .02). Receiver operating characteristic curve analysis of the interval for a significant decrease in the aortic diameter at level D yielded 4.2 months as the optimal threshold for performing TEVAR (area under the curve, 0.859; 95% confidence interval, 0.7-1.0). ConclusionsTEVAR for TBAD will result in favorable outcomes, irrespective of the timing of the procedure. However, it might be more effective to perform TEVAR within 4.2 months of the onset of TBAD, provided that the TEVAR procedure can be performed safely.

Human skull profile and speed of sound estimation using pulse-echo ultrasound signals with deep learning

Transcranial ultrasound brain imaging in human adults remains challenging, largely because human skulls cause severe phase aberration. Prior research has shown that phase aberration can be most accurately corrected if the skull profile (i.e., thickness distribution) and speed of sound are known apriori. We propose a deep-learning-based method to estimate the skull profile and sound speed from pulse-echo ultrasound signals. To demonstrate the feasibility of the method, k-wave simulations were performed to generate ultrasound radiofrequency (RF) signals backscattered from the skulls, using density and speed of sound maps derived from diagnostic CT scans of 5 ex vivo human skulls. An unfocused single-element transducer was simulated for ultrasound transmission and receiving at 0.75 MHz with 4-cycle tone bursts. A one-dimensional convolutional neural network (1D-CNN) model was designed and trained to predict the skull thickness and sound speed from RF signals. In an independent test set, the model yielded a mean absolute error of 0.3 mm for skull thickness prediction and 31 m/s for sound speed prediction. The result demonstrates that the deep learning method is capable of accurately estimating skull thickness and speed of sound, providing a potentially powerful tool for skull phase aberration correction in transcranial ultrasound brain imaging.

Diagnosing chronic rhinosinusitis: a comparative study between diagnostic nasal endoscopy and computed tomographic scan paranasal sinuses

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The term ‘rhinosinusitis’ refers to a heterogenous group of disorders characterized by inflammation of mucosa of the nose and paranasal sinuses. The National Institute of Allergy and Infectious Diseases (NIAID) have recently mentioned that 136 million people of India suffer from chronic rhino sinusitis.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A total 50 patients with symptoms of rhinosinusitis were investigated with both diagnostic nasal endoscopy and CT scan paranasal sinuses and their findings were scored with particular scoring system and compared with each other. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Out of 50 patients, 90% patients were diagnosed on CT scan and 84% patients were diagnosed on nasal endoscopy. By considering CT scan as accurate procedure and correlating nasal endoscopy with CT scan, sensitivity was 88.88%, specificity was 60%, positive predictive value was 95.23%, negative predictive value was 37.5%, and p value was 0.004671, which was significant at p&amp;lt;0.05, indicates that CT paranasal sinuses is more accurate than diagnostic nasal endoscopy in diagnosing chronic rhinosinusitis.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Both diagnostic nasal endoscopy and CT paranasal sinuses are important pre-operative evaluation tools in detecting pathology and both are complementary to each other. But CT paranasal sinuses are more convenient than endoscopy according to this study.&lt;/p&gt;

Dosimetry Comparison of Palliative Radiation Plans Generated From Available Diagnostic CT Images Versus Dedicated CT Simulation for Inpatients.

IntroductionThe morbidity sequelae of advanced cancer are often irreversible. Early palliative radiation can prevent, delay, and even improve these consequences. Treatment may be delayed due to a packed computed tomography (CT) simulation schedule or other logistics, including the cost and burden of arranging ambulance transportation when radiation centers are off-site.ObjectivesThe primary objective was to determine the feasibility of using a recent diagnostic CT scan in lieu of a dedicated simulation CT to generate an adequate plan without sacrificing dosimetric goals and subsequent efficacy or tolerability. Secondary objectives included how much the lesion has grown, and how much earlier treatment could start if planned on a diagnostic CT scan.Materials/MethodsFor each inpatient treated with palliative radiation, a prior recent diagnostic CT scan was imported into the RayStation (RaySearch Laboratories, Stockholm, Sweden) planning system. From these diagnostic scans, planning treatment volumes (PTV) and organs at risk (OAR) were contoured using the same technique as the patient’s actual treatment. The primary outcome was to compare both the PTV coverage and OAR dose between the plan generated from the diagnostic CT compared to that from the simulation CT. Our secondary outcomes include the mean time between CT simulation and first treatment, change in tumor volume between diagnostic scan and CT simulation, and the hottest 1% of each plan (D1).ResultsBetween May and August 2019, a total of 22 inpatients were treated palliatively. Of those 22 patients, 10 patients (ages 32-92 years, median 64.5 years, 50% spine) met study criteria and had a diagnostic CT scan that was obtained within 14 days of simulation CT that was also compatible with our planning software. In the plans that were delivered, a mean of 98.8% (range 94.4-100%) of PTV was covered by at least 95% prescription dose. In the diagnostic CT plans, a mean of 95.4% (range 84.5-100%) of PTV was covered by at least 95% prescription dose. The difference between plans trended towards significance (p=0.061). When looking at patients receiving treatment to the spine or having a diagnostic CT within four days of the simulation CT, there was no statistically significant difference between the two plans (p=0.032 and 0.030, respectively). The OARs received, on average, 1.4% less mean radiation dose in the hypothetical plans (p=0.911). All OAR constraints were met in both groups. The mean time between diagnostic CT and CT simulation was 5.9 days and between CT simulation and first treatment was 1.9 days (range 0-5 days). The mean change in tumor volume was 22.64% smaller in the diagnostic CT scan plan. The D1 was an average 1% hotter in the hypothetical plans (p=0.16).ConclusionIn hospitalized patients with an indication for palliative radiation, treatment planning on a pre-existing recent diagnostic CT scan produces comparable dose distributions without increases in dose to OARs when compared to the use of CT simulation scans, particularly for the treatment of the spine or when a very recent diagnostic CT is available. Bypassing CT simulation in select cases allows for earlier delivery of radiation with less patient and logistical burden. In combination with daily image guidance, this may translate to more timely delivery of radiation, less cost and burden to critically ill patients, and improved palliative benefit.

Management of Acute Appendicitis During the COVID-19 Pandemic is Significantly Different: A Retrospective Single UK Hospital Study.

IntroductionThe COVID-19 pandemic has led to a change in the delivery of acute and emergency surgical services. With emphasis on reducing unnecessary operative intervention and performing more CT scans, there has been a shift in managing acute appendicitis conservatively. We evaluate the impact of this shift on the management of acute appendicitis.MethodsA single UK centre retrospective study evaluating patients with suspected acute appendicitis pre-COVID-19 rota (18 March 2020) and post-COVID rota implementation. Data including demographics, inflammatory markers, imaging, mode of management and operative findings were collected. Logistic regression with SPSS was used to determine which factors were associated with conservative management and treated with antibiotics.ResultsA total of 161 patients were analysed, 82 pre-COVID19 and 79 post-COVID19. Of the pre-COVID-19 patients, 67.07% underwent appendicectomy while the rest were conservatively managed; 24.3% of these patients underwent a CT scan only. Post-COVID-19, 22.78% of patients underwent appendicectomy with a higher percentage of diagnostic CT scans performed, 43/79 (54.4%, p <0.001). The proportion of histologically normal appendicectomies was significantly reduced in the post-COVID-19 era (12.78% vs 0.00%; p-value 0.001). Logistic regression analysis showed a normal WCC to be associated with greater likelihood of conservative management. No conservatively managed patients returned to theatre in the 30-day follow-up period.ConclusionDue to the restrictions imposed by the post-COVID-19 rota, a greater proportion of patients were managed conservatively with comparable patient outcomes. The approach also led to fewer negative appendicectomies owing to greater reliance on imaging.

A deep-learning method using computed tomography scout images for estimating patient body weight

Body weight is an indispensable parameter for determination of contrast medium dose, appropriate drug dosing, or management of radiation dose. However, we cannot always determine the accurate patient body weight at the time of computed tomography (CT) scanning, especially in emergency care. Time-efficient methods to estimate body weight with high accuracy before diagnostic CT scans currently do not exist. In this study, on the basis of 1831 chest and 519 abdominal CT scout images with the corresponding body weights, we developed and evaluated deep-learning models capable of automatically predicting body weight from CT scout images. In the model performance assessment, there were strong correlations between the actual and predicted body weights in both chest (ρ = 0.947, p < 0.001) and abdominal datasets (ρ = 0.869, p < 0.001). The mean absolute errors were 2.75 kg and 4.77 kg for the chest and abdominal datasets, respectively. Our proposed method with deep learning is useful for estimating body weights from CT scout images with clinically acceptable accuracy and potentially could be useful for determining the contrast medium dose and CT dose management in adult patients with unknown body weight.

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Recently, a diagnostic helical CT is integrated into a linear accelerator, called uRT-linac 506c, whose CT scanning dataset can be directly used to do simulation. This novel structure provides a possibility for online adaptive radiotherapy. For adaptive radiotherapy, the carbon fiber couch is an essential external device for supporting and positioning patients. And the effect on dose attenuation and distribution caused by a couch is inevitable and vital for precise treatment. In this research, the couch equipped with uRT-linac 506c was evaluated on the radiation dosimetry effect. The treatment couch equipped on the uRT-linac 506c accelerator was evaluated, and its effect on the attenuation, surface dose and dose buildup were measured for different phantom positions (offset = 0 cm, offset = + 10 cm and offset = − 10 cm, respectively) and different gantry angles. Since uRT-linac 506c is exclusively capable to provide diagnostic CT scanning data with real relative electron density (RED), this CT scanning data of the couch can be used directly in uRT-TPS to design plans. This scanned couch dataset was designated as the model A. The model B was a dummy structure of a treatment couch inserted with artificially preset RED. The dose calculation accuracy of these two models was compared using PB, CC, and MC on uRT-TPS. With the effect of carbon fiber couch, the surface dose was increased at least 97.94% for 25 × 25 cm2 field and 188.83% for 10 × 10 cm2 field, compared with those without. At different phantom positions (offset = 0, + 10, − 10 cm), the attenuation for 6 MV photon beam at gantry angle 180° were 4.4%, 4.4%, and 4.3%, respectively, and varied with changes of gantry angle. There do exists dose deviation between measurement and TPS calculation with the involvement of treatment couch, among the three algorithms, MC presented the least deviation, and the model A made less and steadier deviation than the model B, showing promising superiority. The attenuation, surface dose, and buildup effects of the carbon fiber couch in this study were measured similarly to most counterparts. The dose deviation calculated based on the couch dataset scanned by the diagnostic helical CT was smaller than those based on a dummy couch. This result suggests that an accelerator equipped with a diagnostic CT, which can help reduce the dose deviation of the carbon fiber couch, is a promising platform for online adaptive radiotherapy.

Prediction of recurrence after surgery in colorectal cancer patients using radiomics from diagnostic contrast-enhanced computed tomography: a two-center study.

To assess the value of contrast-enhanced (CE) diagnostic CT scans characterized through radiomics as predictors of recurrence for patients with stage II and III colorectal cancer in a two-center context. This study included 193 patients diagnosed with stage II and III colorectal adenocarcinoma from 1 July 2008 to 15 March 2017 in two different French University Hospitals. To compensate for the variability in two-center data, a statistical harmonization method Bootstrapped ComBat (B-ComBat) was used. Models predicting disease-free survival (DFS) were built using 3 different machine learning (ML): (1) multivariate regression (MR) with 10-fold cross-validation after feature selection based on least absolute shrinkage and selection operator (LASSO), (2) random forest (RF), and (3) support vector machine (SVM), both with embedded feature selection. The performance for both balanced and 95% sensitivity models was systematically higher after our proposed B-ComBat harmonization compared to the use of the original untransformed data. The most clinically relevant performance was achieved by the multivariate regression model combining a clinical variable (postoperative chemotherapy) with two radiomics shape descriptors (compactness and least axis length) with a BAcc of 0.78 and an MCC of 0.6 associated with a required sensitivity of 95%. The resulting stratification in terms of DFS was significant (p = 0.00021), especially compared to the use of unharmonized original data (p = 0.17). Radiomics models derived from contrast-enhanced CT could be trained and validated in a two-center cohort with a good predictive performance of recurrence in stage II et III colorectal cancer patients. • Adjuvant therapy decision in colorectal cancer can be a challenge in medical oncology. • Radiomics models, derived from diagnostic CT, trained and validated in a two-center cohort, could predict recurrence in stage II and III colorectal cancer patients. • Identifying patients with a low risk of recurrence, these models could facilitate treatment optimization and avoid unnecessary treatment.