Combination Of Computed Tomography Research Articles

Combined ultrasonography and CT for prognosis and predicting clinical outcomes of patients with pseudomyxoma peritonei

ObjectivesThis study aimed to identify the diagnostic accuracy of combined ultrasonography (US) and computed tomography (CT) in evaluating the tumor burden of pseudomyxoma peritonei (PMP). Besides, we assessed the ability of this combination to predict the likelihood of complete resection.MethodsThis retrospective study involved 504 patients diagnosed with PMP and scheduled for cytoreduction surgery. We compared tumor burden—quantified as peritoneal cancer index (PCI) by preoperative US and CT (US-CT-PCI)—with surgical findings. Next, we assessed the prognostic value of US-CT PCI and imaging features in determining the completeness of cytoreduction (CCR) score using multivariate analysis.ResultsUS-CT PCI demonstrated a high PCI evaluation accuracy under moderate tumor burden. Higher US-CT PCI could predict incomplete resection. In addition, we identified imaging features such as mesenteric involvement as an independent predictor of incomplete resection (hazard ratio (HR) = 2.006; p = 0.007).ConclusionsUS-CT PCI allowed us to predict the completeness of cytoreductive surgery in patients with PMP. Moreover, the combined US and CT imaging detected several features indicating incomplete cytoreduction.Key Points• Ultrasonography (US) can act as a complementary diagnostic modality in peritoneal cancer index (PCI) evaluation by combining CT in the small bowel area and US in the abdominal area.• A modified peritoneal cancer index (US-CT PCI) helps preoperatively evaluate tumor burden with high accuracy and allows to predict incomplete resection.• US-CT PCI of 20 or above and the involvement of particular structures such as mesentery, independently indicate incomplete resection.

MRI-only radiotherapy from an economic perspective: Can new techniques in prostate cancer treatment be cost saving?

Background and PurposeThe aim of this study was to analyze a magnetic resonance imaging (MRI)-only radiotherapy workflow from an economic perspective in terms of reduced time, costs and systematic uncertainties. Material/MethodsA documented Swedish clinical implementation of MRI-only radiotherapy was used as template for cost assessments compared to a combined computed tomography (CT)/MRI workflow. The costs were taken from official regional price lists from 2021. MRI-only specific quality assurance (QA) was assumed necessary in an initial phase. Treatment plans for target volumes with margins of 5–10 mm were created for ten prostate cancer patients prescribed 78 Gy in 39 fractions. The risk of Grade ≥ 2 rectal toxicity or rectal bleeding was calculated using the QUANTEC recommended NTCP model and costs estimated based on subsequent diagnostic examinations. ResultsThe exclusion of the CT-examination and faster target delineation were the main contributors to cost reductions. Additional QA procedures limited the initial cost reduction to 14 EUR/patient. Long-term MRI-only reduced the costs by 209 EUR/patient. Reducing margins resulted in Grade ≥ 2 rectal toxicity or rectal bleeding probability of 9.7 % for 7 mm margin and 6.0 % for 5 mm margin. This margin reduction resulted in an additional cost reduction of 46 EUR/patient. ConclusionAn MRI-only workflow implementation is associated with reduced costs when the workflow tasks are more time efficient and side effects are reduced as a result of margin reduction. The short-term economic benefits are limited due to extra costs of QA procedures. The economic benefits of MRI-only will make impact first when the workflow is well established, and margin reduction has been included.

Scanning pulsed laser ablation in liquids: An alternative route to obtaining biocompatible YbFe nanoparticles as multiplatform contrast agents for combined MRI and CT imaging

Ytterbium ferrites are being used in many promising applications, such as visible-light photocatalysis, solar cells, magnetooptic devices, electro-magnetic equipment, etc., due to their fantastic ferroelectric and ferromagnetic properties. However, despite their good magnetic and radiopaque features, the use of ytterbium ferrites as multiplatform contrast agents in magnetic resonance imaging (MRI) and X-ray computed tomography (CT) is still under-developed. This is mainly due to difficulties in obtaining stable and biocompatible aqueous colloidal dispersions of ytterbium ferrite nanoparticles. In order to overcome this limitation, this work explores an eco-friendly method to directly synthesize such dispersions by liquid-assisted pulsed laser ablation of ytterbium ferrite massive targets. First, orthorhombic bulk YbFeO3 targets were obtained by a reaction-sintering method. Then, colloidal dispersions of nanoparticles were produced directly in both distilled water and ethanol by irradiating the bulk YbFeO3 targets with high-power infrared nanosecond lasers pulses. A battery of techniques has been used to characterize the as synthesized YbFeO3 targets and colloidal dispersions of YbFe nanoparticles to determine their composition, structure, magnetic properties, X-ray attenuation potentials, and colloidal properties. Moreover, the biocompatibility of the systems was also analysed by MTT cell viability assay. Results indicated that the use of distilled water as ablation medium yields colloidal dispersions consisted mainly of paramagnetic ytterbium ferrite nanoparticles. Contrarily, the use of ethanol as solvent leads to colloidal dispersions of polycrystalline nanoparticles with both ferromagnetic and paramagnetic behaviour, due to the coexistence, in each nanoparticle, of ytterbium ferrite, ytterbium oxide, and iron oxide crystalline phases. Both colloidal dispersions exhibit also high biocompatibility and suitable X-ray attenuation properties. Moreover, they show bio-safe hydrodynamic sizes (lower than 200 nm) with acceptable overall hydrodynamic polydispersity index values (under 0.4), being stable in water for several weeks. These results pave the way for the future evaluation of Yb–Fe based nanoparticles as multiplatform contrast agents in multimodal MRI and CT imaging.

Fluorescence guidance improves the accuracy of radiological imaging-guided surgical navigation.

Imaging-based navigation technologies require static referencing between the target anatomy and the optical sensors. Imaging-based navigation is therefore well suited to operations involving bony anatomy; however, these technologies have not translated to soft-tissue surgery. We sought to determine if fluorescence imaging complement conventional, radiological imaging-based navigation to guide the dissection of soft-tissue phantom tumors. Using a human tissue-simulating model, we created tumor phantoms with physiologically accurate optical density and contrast concentrations. Phantoms were dissected using all possible combinations of computed tomography (CT), magnetic resonance, and fluorescence imaging; controls were included. The data were margin accuracy, margin status, tumor spatial alignment, and dissection duration. Margin accuracy was higher for combined navigation modalities compared to individual navigation modalities, and accuracy was highest with combined CT and fluorescence navigation (p = 0.045). Margin status improved with combined CT and fluorescence imaging. At present, imaging-based navigation has limited application in guiding soft-tissue tumor operations due to its inability to compensate for positional changes during surgery. This study indicates that fluorescence guidance enhances the accuracy of imaging-based navigation and may be best viewed as a synergistic technology, rather than a competing one.

A Proposal for a Standardized Imaging Algorithm to Improve the Accuracy and Reliability for the Diagnosis of Thoracolumbar Posterior Ligamentous Complex Injury in Computed Tomography and Magnetic Resonance Imaging.

Systematic Literature Review. To propose a systematic imaging algorithm for diagnosing posterior ligamentous complex (PLC) injury in computed tomography (CT) and magnetic resonance imaging (MRI) to improve the reliability of PLC assessment. A systematic review was conducted following PRISMA guidelines. The Scopus database was searched from its inception until July 21, 2022, for studies evaluating CT or MRI assessment of the PLC injury following thoracolumbar trauma. The studies extracted key findings, objectives, injury definitions, and radiographic modalities. Twenty-three studies were included in this systematic review, encompassing 2021 patients. Five studies evaluated the accuracy of MRI in detecting thoracolumbar PLC injury using intraoperative findings as a reference. These studies indicate that black stripe discontinuity due to supraspinous or ligamentum flavum rupture is a more specific criterion of PLC injury than high-signal intensity. Thirteen papers evaluated the accuracy or reliability of CT in detecting thoracolumbar PLC injury using MRI or intraoperative findings as a reference. The overall accuracy rate of CT in detecting PLC injury was 68-90%. Two studies evaluate the accuracy of combined CT findings, showing that ≥2 CT findings are associated with a positive predictive value of 88-91 %. Vertebral translation, facet joint malalignment, spinous process fracture, horizontal laminar fracture, and interspinous widening were independent predictors of PLC injury. We provided a comprehensive imaging algorithm for diagnosing PLC in CT and MRI based on available literature and our experience. The algorithm will potentially improve the accuracy and reliability of PLC assessment, however it needs multicentre prospective validation.

Differentiating Primary Tumors for Brain Metastasis with Integrated Radiomics from Multiple Imaging Modalities

Objectives To differentiate the primary site of brain metastases (BMs) is of high clinical value for the successful management of patients with BM. The purpose of this study is to investigate a combined radiomics model with computer tomography (CT) and magnetic resonance imaging (MRI) images in differentiating BMs originated from lung and breast cancer. Methods Pretreatment cerebral contrast enhanced CT and T1-weighted MRI images of 78 patients with 179 BMs from primary lung and breast cancer were retrospectively analyzed. Radiomic features were extracted from contoured BM lesions and selected using the Mann–Whitney U test and the least absolute shrinkage and selection operator (LASSO) logistic regression. Binary logistic regression (BLR) and support vector machine (SVM) models were built and evaluated based on selected radiomic features from CT alone, MRI alone, and combined images to differentiate BMs originated from lung and breast cancer. Results A total of 10 and 6 optimal radiomic features were screened out of 1288 CT and 1197 MRI features, respectively. The mean area under the curves (AUCs) of the BLR and SVM models using fivefolds cross-validation were 0.703 vs. 0.751, 0.718 vs. 0.754, and 0.781 vs. 0.803 in the training dataset and 0.708 vs. 0.763, 0.715 vs. 0.717, and 0.771 vs. 0.805 in the testing dataset for models with CT alone, MRI alone, and combined CT and MRI radiomic features, respectively. Conclusions Radiomics model based on combined CT and MRI features is feasible and accurate in the differentiation of the primary site of BMs from lung and breast cancer.

Comparative Study of Application of Computed Tomography/Ultrasound and Computed Tomography Imaging Guidance Methods in the Microwave Ablation of Liver Cancer.

The aim of the study is to assess the clinical value of the combined computed tomography (CT)/ultrasound (US) guidance in microwave ablation (MWA) for hepatocellular carcinoma (HCC). From July 16, 2016, to June 20, 2021, medical records of 150 HCC patients treated with MWA were retrospectively analyzed. Ninety-two patients with 115 liver tumors underwent MWA under combined CT/US guidance, and 58 patients with 73 liver tumors received MWA under CT guidance alone. The clinical efficacy of combined CT/US-guided MWA was analyzed. We compared the complications, procedure time, and CT scan times between the 2 groups. The total complete ablation rate and complete ablation rate of high-risk location tumors were significantly higher in the group treated with combined CT/US guidance ( P = 0.0471 and P = 0.0347, respectively), the imaging guidance modality (odds ratio, 0.303; 95% confidence interval [CI], 0.095-0.970; P = 0.044) was an independent factor for ablation efficacy. These 2 groups also had significant differences in the procedure time ( P = 0.0171), the incidence rate of pneumothorax ( P = 0.0209), abdominal pain ( P = 0.0196), nausea or vomiting ( P = 0.0026), and intraoperative CT scan times ( P < 0.001). The overall complication rates ( P = 0.4023) and recurrence rates ( P = 0.5063) between the 2 groups were not statistically significant. However, CT/US group has a better short-term progressive free survival (log-rank P = 0.103, Breslow P = 0.030). In multivariate analysis, guidance modality (hazard ratio, 0.586; 95% CI, 0.368-0.934; P = 0.025) and Barcelona Clinic Liver Cancer stage (hazard ratio, 2.933; 95% CI, 1.678-5.127; P < 0.001) were risk factor for progressive free survival. Percutaneous MWA under the combined CT/US guidance for HCC can improve clinical benefits.

External validation of the NeuroImaging Radiological Interpretation System and Helsinki computed tomography score for mortality prediction in patients with traumatic brain injury treated in the intensive care unit: a Finnish intensive care consortium study

BackgroundAdmission computed tomography (CT) scoring systems can be used to objectively quantify the severity of traumatic brain injury (TBI) and aid in outcome prediction. We aimed to externally validate the NeuroImaging Radiological Interpretation System (NIRIS) and the Helsinki CT score. In addition, we compared the prognostic performance of the NIRIS and the Helsinki CT score to the Marshall CT classification and to a clinical model.MethodsWe conducted a retrospective multicenter observational study using the Finnish Intensive Care Consortium database. We included adult TBI patients admitted in four university hospital ICUs during 2003–2013. We analyzed the CT scans using the NIRIS and the Helsinki CT score and compared the results to 6-month mortality as the primary outcome. In addition, we created a clinical model (age, Glasgow Coma Scale score, Simplified Acute Physiology Score II, presence of severe comorbidity) and combined clinical and CT models to see the added predictive impact of radiological data to conventional clinical information. We measured model performance using area under curve (AUC), Nagelkerke’s R2 statistics, and the integrated discrimination improvement (IDI).ResultsA total of 3031 patients were included in the analysis. The 6-month mortality was 710 patients (23.4%). Of the CT models, the Helsinki CT displayed best discrimination (AUC 0.73 vs. 0.70 for NIRIS) and explanatory variation (Nagelkerke’s R2 0.20 vs. 0.15). The clinical model displayed an AUC of 0.86 (95% CI 0.84–0.87). All CT models increased the AUC of the clinical model by + 0.01 to 0.87 (95% CI 0.85–0.88) and the IDI by 0.01–0.03.ConclusionIn patients with TBI treated in the ICU, the Helsinki CT score outperformed the NIRIS for 6-month mortality prediction. In isolation, CT models offered only moderate accuracy for outcome prediction and clinical variables outweighing the CT-based predictors in terms of predictive performance.

Predicting chemotherapy response in non-small-cell lung cancer via computed tomography radiomic features: Peritumoral, intratumoral, or combined?

PurposeThis study aims to evaluate the ability of peritumoral, intratumoral, or combined computed tomography (CT) radiomic features to predict chemotherapy response in non-small cell lung cancer (NSCLC).MethodsAfter excluding subjects with incomplete data or other types of treatments, 272 (Dataset 1) and 43 (Dataset 2, external validation) NSCLC patients who were only treated with chemotherapy as the first-line treatment were enrolled between 2015 and 2019. All patients were divided into response and nonresponse based on the response evaluation criteria in solid tumors, version 1.1. By using 3D slicer and morphological operations in python, the intra- and peritumoral regions of lung tumors were segmented from pre-treatment CT images (unenhanced) and confirmed by two experienced radiologists. Then radiomic features (the first order, texture, shape, et al.) were extracted from the above regions of interest. The models were trained and tested in Dataset 1 and further validated in Dataset 2. The performance of models was compared using the area under curve (AUC), confusion matrix, accuracy, precision, recall, and F1-score.ResultsThe radiomic model using features from the peritumoral region of 0–3 mm outperformed that using features from 3–6, 6–9, 9–12 mm peritumoral region, and intratumoral region (AUC: 0.95 versus 0.87, 0.86, 0.85, and 0.88). By the fusion of features from 0–3 and 3–6 mm peritumoral regions, the logistic regression model achieved the best performance, with an AUC of 0.97. This model achieved an AUC of 0.85 in the external cohort. Moreover, among the 20 selected features, seven features differed significantly between the two groups (p < 0.05).ConclusionsCT radiomic features from both the peri- and intratumoral regions can predict chemotherapy response in NSCLC using machine learning models. Combined features from two peritumoral regions yielded better predictions.

Diagnostic Strategy and Prognostic Factors for Ectopic Adrenocorticotropic Hormone Syndrome: A Retrospective Study of 64 Cases

Introduction: Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) is a serious life-threatening disease. Tumor localization is crucial in EAS management. This underscores the importance of evaluating imaging methods and prognostic factors to provide a clear basis for patient diagnosis and management. Objective: The aim of this study was to investigate imaging methods and analyze the relevant prognostic factors for EAS. Methods: The retrospective study followed 64 cases of EAS diagnosed between 1992 and 2020. Clinical features, biochemical analysis, and imaging studies were collected, and survival data were followed up and analyzed. Results: Of 64 patients, 41% were female with a mean (±SD) age at diagnosis of 47 ± 16 years. Computed tomography (CT), 18-F fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)-CT, and octreotide scintigraphy had similar sensitivity in localizing ectopic ACTH-secreting tumors. However, in cases with negative imaging on CT, both of ¹⁸F-FDG PET-CT and octreotide scintigraphy further localized 25% tumors. The combination of all three modalities failed to further increase the sensitivity. Patients with thymic tumors survived longer than those with pulmonary or pancreatic tumors (p = 0.013 and 0.047, respectively). Multivariate analyses showed that hypokalemia (p = 0.004) and treatment modality (p = 0.048) were independent prognostic factors. The optimal serum potassium cutoff based on maximum log-rank statistics (p = 0.012) was 2.90 mmol/L. Conclusion: CT is the first choice for tumor localization in EAS. CT in combination with a nuclear medicine or molecular imaging modality is necessary for further identification of an ectopic source. Serum potassium <2.90 mmol/L is associated with shorter overall survival, and tumor resection plays the most important role in the survival improvement.

A Combination of Preoperative Computed Tomography-Defined Sarcopenia and Systemic Inflammation on Survival in Patients with Poorly Differentiated Neuroendocrine Neoplasms Following Radical Resection

This retrospective study of 122 patients with gastrointestinal poorly differentiated neuroendocrine neoplasms (GI-PDNEN) who underwent radical resection between January 2010 and December 2020 aimed to investigate the usefulness of combined computed tomography (CT)-defined sarcopenia and systemic inflammation to evaluate long-term prognoses for patients who underwent radical surgical resection. Sarcopenia, based on a pre-defined L3 skeletal muscle index cutoff value, was assessed using preoperative abdominal CT images. Patients (neuroendocrine carcinoma, 86 patients; mixed adenoneuroendocrine carcinoma, 36 patients) were divided into low-, intermediate-, and high-risk groups using sarcopenia scores and neutrophil-to-lymphocyte ratios (SNLRs). Higher SNLRs were significantly associated with higher age (P = 0.004), larger tumor size (P = 0.042), lower body mass index (P = 0.042), and lower hemoglobin (P = 0.001) and albumin (P = 0.031) levels. Multivariate analysis indicated that a higher SNLR was an independent risk factor for poor overall survival (OS, P = 0.01) and relapse-free survival (RFS, P = 0.001) in patients with GI-PDNEN postoperatively. Sarcopenia and a higher NLR were significantly associated with poor RFS and OS following radical resection. The SNLR had a definite predictive prognostic value in preoperatively identifying patients with GI-PDNEN and a probable poor long-term prognosis, especially those with neuroendocrine carcinoma.

COVID-19 Diagnosis in Patients With Acute Abdominal Pain Without Respiratory Symptoms: A UK Emergency General Surgical Unit Experience.

BackgroundRecent evidence has emerged reporting atypical clinical symptoms of the novel coronavirus (COVID-19). There is a sparsity of existing studies examining COVID-19-related abdominal pain and the role of investigative imaging for the virus in these patients. Study aims were to determine COVID-19 incidence in those with acute abdominal pain in the absence of respiratory symptoms and to assess the diagnostic performance of CT thoracic imaging in such patients.MethodsRetrospective analysis of all consecutive patients admitted to our emergency general surgical unit between 1st March 2020 and 31st May 2020 was performed. In adherence with national guidelines, all patients underwent nasal and oro-pharyngeal COVID-19 RT-PCR swabs as well as thoracic and abdominal computed tomography (CT) on admission.ResultsFrom 112 patients admitted with acute abdominal pain in the absence of respiratory symptoms, 16 (14.3%) tested positive for COVID-19 on RT-PCR swab testing. Overall, 50% (8/16) of these patients had no intra-abdominal pathology on CT. The sensitivity and specificity of CT thoracic imaging for diagnosing COVID-19 was 43.8% and 91.7%, respectively. Patients with positive COVID-19 swabs had higher C-reactive protein levels, lower potassium levels and a higher proportion of those with a low lymphocyte count.DiscussionOne in seven patients with abdominal pain without any respiratory symptoms tested positive for COVID-19. Half of these patients represented COVID-19 manifesting primarily as acute abdominal pain. Combined swab testing and CT imaging should be performed in all abdominal pain presentations due to the varying diagnostic performance of thoracic CT in diagnosing COVID-19.

ISOLATED PANCREATIC INJURIES: A CASE SERIES

Context: Pancreatic injuries constitutes a set of rare abdominal solid organ injuries. Isolated pancreatic injuries are even more rare injuries and are often missed in initial clinical and radiological evaluation . such injuries present late and denitive guidelines to manage such injuries are lacking, considering rarity of such injuries. Unpredictable course involves traumatic pancreatitis, pancreatic necrosis, peripancreatic collections, infective complications and extra abdominal complication The aim of this study is to present clinical details and management outcomes of such casesAims: at our institute This study is a retrospective analytical study In this retrospective study medicalSettings and Design: Methods and Material: records of all the admissions were collected from trauma registry from may 2016 to april 2022 at Thanjavur medical college. All these records were screened for patients with isolated pancreatic injuries All continuous variables were analyzed with descriptive statisticsStatistical analysis used: and their mean, median, mode, range and frequencies were calculated. All categorical data are analyzed with frequencies. Comparison of data is done using: all nominal data is analyzed with parametric tests (Chi-square test, unpaired t test) and non-nominal data is analyzed with non- parametric tests (Fischer's exact test and Mann-whitney U test). In our study a total of 22 cases were included. Mean age being 33.91yearsResults: among which 81.8% were males. 72.7% of the patients suffered road trafc accidents. 77.3% of the patients had BMI less than 25. Main pancreatic duct (MPD) involvement was noticed in 22.7% patients. median levels of serum amylase levels were 390U/L. 22.7% patients underwent operative management were as rest were managed non-operatively. Two patients died due to severe pancreatitis. Isolated pancreatic injuries inConclusions: patients where surgery is otherwise not indicated due to other causes needs management tailored to the clinical needs of the patient. Diagnostic ambiguity is best resolved by combining computed tomography (CT) and Magnetic resonance cholangiopancreatography (MRCP). Patients with distal MPD injury are usually operated when presented early and pancreatic stenting is considered when proximal ductal injury is noticed. In selected cases conservative approach is not a contraindication, even in patients with MPD injury, considering high stula and peripancreatic collection rates in distal pancreatectomy.

Differential diagnoses of gallbladder tumors using CT-based deep learning.

The differential diagnosis between gallbladder cancer (GBC) and xanthogranulomatous cholecystitis (XGC) remains quite challenging, and can possibly lead to improper surgery. This study aimed to distinguish between XGC and GBC by combining computed tomography (CT) images and deep learning (DL) to maximize the therapeutic success of surgery. We collected a dataset, including preoperative CT images, from 28 cases of GBC and 21 XGC patients undergoing surgery at our facility. It was subdivided into training and validation (n=40), and test (n=9) datasets. We built a CT patch-based discriminating model using a residual convolutional neural network and employed 5-fold cross-validation. The discriminating performance of the model was analyzed in the test dataset. Of the 40 patients in the training dataset, GBC and XGC were observed in 21 (52.5%), and 19 (47.5%) patients, respectively. A total of 61 126 patches were extracted from the 40 patients. In the validation dataset, the average sensitivity, specificity, and accuracy were 98.8%, 98.0%, and 98.5%, respectively. Furthermore, the area under the receiver operating characteristic curve (AUC) was 0.9985. In the test dataset, which included 11 738 patches, the discriminating accuracy for GBC patients after neoadjuvant chemotherapy (NAC) (n=3) was insufficient (61.8%). However, the discriminating model demonstrated high accuracy (98.2%) and AUC (0.9893) for cases other than those receiving NAC. Our CT-based DL model exhibited high discriminating performance in patients with GBC and XGC. Our study proposes a novel concept for selecting the appropriate procedure and avoiding unnecessary invasive measures.

The usefulness and positive predictive value of ultrasonography and computed tomography in the diagnosis of acute appendicitis in adults: A retrospective study

ObjectiveTo analyze the evolution of the use of imaging tests (ultrasonography and computed tomography (CT)) in the diagnosis of acute appendicitis. To determine the positive predictive value of these tests and the percentage of negative and complicated appendectomies. Material and methodsThis retrospective study compared adults who underwent appendectomy for suspected acute appendicitis at our tertiary hospital during 2015 versus similar patients at our center during 2007. ResultsA total of 278patients were included. The rate of negative appendectomies descended to 5%. The positive predictive value of ultrasonography increased to 97.4% in 2015, and the positive predictive value of CT and combined CT and ultrasonography was 100%. The rate of complicated appendicitis increased (23% in 2015). ConclusionsThe use of imaging tests increased, and the rate of “blind” laparotomies decreased. Nevertheless, the rate of complicated appendicitis increased.

Classification of acute diverticulitis in the left colon with ultrasonography and computed tomography: Value of current severity classification schemes

Background and aimsThe current management of acute diverticulitis of the left colon (ADLC) requires tests with high prognostic value. This paper analyzes the usefulness of ultrasonography (US) in the initial diagnosis of ADLC and the validity of current classifications schemes for ADLC. PatientsThis retrospective observational study included patients with ADLC scheduled to undergo US or computed tomography (CT) following a clinical algorithm. According to the imaging findings, ADLC was classified as mild, locally complicated, or complicated. We analyzed the efficacy of US in the initial diagnosis and the reasons why CT was used as the first-line technique. We compared the findings with published classifications schemes for ADLC. ResultsA total of 311 patients were diagnosed with acute diverticulitis; 183 had ADLC, classified at imaging as mild in 104, locally complicated in 60, and complicated in 19. The diagnosis was reached by US alone in 98 patients, by CT alone in 77, and by combined US and CT in 8. The main reasons for using CT as the first-line technique were the radiologist’s lack of experience in abdominal US and the unavailability of a radiologists on call. Six patients diagnosed by US were reexamined by CT, but the classification changed in only three. None of the published classification schemes included all the imaging findings. ConclusionsUS should be the first-line imaging technique in patients with suspected ADLC. Various laboratory and imaging findings are useful in establishing the prognosis of ADLC. New schemes to classify the severity of ADLC are necessary to ensure optimal clinical decision making.

Damage Evolution of Frozen-Thawed Granite Based on High-Resolution Computed Tomographic Scanning

Freeze-thaw damage of rocks is one of significant natural causes for geo-hazards such as collapse and rockfall in alpine areas. To explore damage evolution in granite in a freeze-thaw environment, specimens of granite in Nyingchi Prefecture, Tibet, China were collected as research objects. Saturated and dry rock specimens were subjected to cyclic freeze-thaw tests of 0, 36, 72, and 144 cycles and freeze-thaw damage of the rock was analyzed by combining computed tomography (CT) scanning and three-dimensional (3D) visualization. Results show that the peak stress of granite decreases to different extents with the increasing number of freeze-thaw cycles; compared with dry rock specimens, saturated granite deteriorates more significantly and shows obviously different stress–strain curves under loading. The moisture condition exerts significant influences on the degree of freeze-thaw damage to granite: after 144 freeze-thaw cycles, the mass loss rates of dry and saturated rock specimens are 0.06% and 0.44% and their loss rates of uniaxial compressive strength (UCS) reach 4.08% and 26.2%, respectively. Under freeze-thaw cycles, the frost heave of pore water causes initiation and development of micro-defects and new micro-cracks mainly develop along relatively weak areas such as inherent defects (pores and fractures) and boundaries between different mineral crystals, resulting in intergranular and transgranular cracking. For dry rock specimens, the non-uniform contraction and expansion of minerals therein are main causes for deterioration inside the rock. The freeze-thaw damage of rocks is calculated using the improved elastic modulus loss method. The damage development trend conforms to the strength deterioration trend and the pore development in the rock, reflecting the evolution of freeze-thaw damage to granite.

Quantitative thrombus characteristics on thin-slice computed tomography improve prediction of thrombus histopathology: results of the MR CLEAN Registry

ObjectivesThrombus computed tomography (CT) characteristics might be used to assess histopathologic thrombus composition in patients treated with endovascular thrombectomy (EVT) for acute ischemic stroke (AIS). We aimed to assess the variability in thrombus composition that could be predicted with combined thrombus CT characteristics.MethodsThrombi of patients enrolled in the MR CLEAN Registry between March 2014 and June 2016 were histologically analyzed with hematoxylin-eosin staining and quantified for percentages of red blood cells (RBCs) and fibrin/platelets. We estimated the association between general qualitative characteristics (hyperdense artery sign [HAS], occlusion location, clot burden score [CBS]) and thrombus composition with linear regression, and quantified RBC variability that could be explained with individual and combined characteristics with R2. For patients with available thin-slice (≤ 2.5 mm) imaging, we performed similar analyses for general and quantitative characteristics (HAS, occlusion location, CBS, [relative] thrombus density, thrombus length, perviousness, distance from ICA-terminus).ResultsIn 332 included patients, the presence of HAS (aβ 7.8 [95% CI 3.9–11.7]) and shift towards a more proximal occlusion location (aβ 3.9 [95% CI 0.6–7.1]) were independently associated with increased RBC and decreased fibrin/platelet content. With general characteristics, 12% of RBC variability could be explained; HAS was the strongest predictor. In 94 patients with available thin-slice imaging, 30% of RBC variability could be explained; thrombus density and thrombus length were the strongest predictors.ConclusionsQuantitative thrombus CT characteristics on thin-slice admission CT improve prediction of thrombus composition and might be used to further guide clinical decision-making in patients treated with EVT for AIS in the future.Key Points• With hyperdense artery sign and occlusion location, 12% of variability in thrombus RBC content can be explained.• With hyperdense artery sign, occlusion location, and quantitative thrombus characteristics on thin-slice (≤ 2.5 mm) non-contrast CT and CTA, 30% of variability in thrombus RBC content can be explained.• Absolute thrombus density and thrombus length were the strongest predictors for thrombus composition.

Aortic Area as an Indicator of Subclinical Cardiovascular Disease

Aim: Outward arterial remodeling occurs early in cardiovascular disease (CVD) and, as such, measuring arterial dimension may be an early indicator of subclinical disease. Objective: The objective of our study was to measure area at three aortic locations: The ascending thoracic (ASC), the descending thoracic (DSC), and the abdominal (ABD), and to test for association with traditional CVD risk factors and subclinical CVD throughout the body. Methods: We measured ASC, DSC, and ABD using computed tomography (CT) in 408 African ancestry men aged 50-89 years. We assessed prevalent CVD risk factors via participant interview and clinical exam, and subclinical CVD, including carotid atherosclerosis through B-mode carotid ultrasound, vascular calcification via chest and abdominal CT, and arterial stiffness via pulse-wave velocity (PWV). Results: As expected, all aortic areas were in correlation with each other (r=0.39-0.63, all p&lt;0.0001) and associated with greater age, greater body size, and hypertension (p≤0.01 for all). After adjustment for traditional CVD risk factors, ASC was positively associated with carotid atherosclerosis (p&lt;0.01). A greater area at each location was associated with greater PWV (p&lt;0.03 for all), with the DSC region showing the most significant association. Conclusion: This is the first study to test the association of aortic area measured at multiple points with subclinical CVD. We found that combined CT assessment of ascending and descending aortic area may indicate a high risk of prevalent subclinical CVD elsewhere in the body independent of age, body size, and blood pressure.

Safety and efficacy of percutaneous microwave ablation using combined computed tomography and ultrasound-guided imaging in patients with hepatocellular carcinoma: A retrospective study.

We retrospectively evaluated the safety and efficacy of percutaneous microwave ablation (MWA) using combined computed tomography (CT) and ultrasound (US)-guided imaging in patients with Barcelona Clinic Liver Cancer (BCLC)-A1-3 hepatocellular carcinoma (HCC). We included 88 consecutive patients with single HCC who were treated with transcatheter arterial chemoembolization (TACE) using our database. The patients were divided into three groups. The combination group received MWA under the guidance of nonenhanced CT and US, CT group received MWA under the guidance of nonenhanced CT alone and US group received MWA under the guidance of US alone. The study endpoints included the treatment time, number of puncture, local recurrence rate, and adverse events. The median treatment time and mean puncture number were 38.6 (30-45) min, 1.2 (1-2) times (combination group); 45.8 (35-56) min, 4.2 (3-7) times (CT group); and 36.7 (30-47) min, 1.1 (1-2) times (US group), respectively. The median puncture number was significantly less than in the CT group. The local recurrence rate in the combination group was significantly inferior to that in the US group. There was a statistically significant difference between the combination group and CT group in Grade C complication rate. Combining CT-and US-guide MWA in patients with BCLC-A1-3 HCC appeared to be much better than the use of guidance of CT or US alone.