Computed tomography in patients with sepsis presenting to the emergency department: exploring its role in light of patient outcomes.

OBJECTIVES: This study aimed to explore the role of CT in septic patients presenting to the emergency department (ED). MATERIALS AND METHODS: We performed a retrospective secondary analysis of 192 septic patients from a prospective observational study, i.e., the "LIFE POC" study. Sepsis was diagnosed in accordance with the Sepsis-3 definition. Clinical and radiological data were collected from the hospital administration and radiological systems. Information on mortality and morbidity was collected. Time-to-CT between CT scan and sepsis diagnosis (ttCTsd) was calculated. Diagnostic accuracy was assessed with the final sepsis source as reference standard. The reference standard was established through the treating team of the patient based on all available clinical, imaging, and microbiological data. RESULTS: Sixty-two of 192 patients underwent a CT examination for sepsis focus detection. The final septic source was identified by CT in 69.4% (n = 43). CT detected septic foci with 81.1% sensitivity (95% CI, 68.0-90.6%) and 55.6% specificity (95% CI, 21.2-86.3%). Patients with short versus long ttCTsd did not differ in terms of mortality (16.1%, n = 5 vs 9.7, n = 3; p = 0.449), length of hospital stay (median 16 d, IQR 9 d 12 h-23 d 18 h vs median 13 d, IQR 10 d 00 h-24 d 00 h; p = 0.863), or duration of intensive care (median 3d 12 h, IQR 2 d 6 h-7 d 18 h vs median 5d, IQR 2 d-11 d; p = 0.800). CONCLUSIONS: Our findings show a high sensitivity of CT in ED patients with sepsis, confirming its relevance in guiding treatment decisions. The low specificity suggests that a negative CT requires further ancillary diagnostic tests for focus detection. The timing of CT did not affect morbidity or mortality outcomes. CLINICAL RELEVANCE STATEMENT: In patients with sepsis who present to the ED, CT can be used to identify infectious foci on the basis of clinical suspicion, but should not be used as a rule-out test. Scientific evidence for the optimal timing of CT beyond clinical decision-making is currently missing, as potential mortality benefits are clouded by differences in clinical severity at the time of ED presentation. KEY POINTS: • In patients with sepsis who present to the ED, CT for focus identification has a high sensitivity and can thereby be valuable for patient management. • As the specificity is considerably lower, a thorough microbiological assessment is important in these cases. • The timing of CT did not affect morbidity and mortality outcomes in this study, which might be due to variability in clinical severity at the time of ED presentation.

Computed tomography-based thermography (CTT) in microwave ablation: prediction of the heat ablation zone in the porcine liver.

OBJECTIVES: The aim of the study was to investigate computed tomography-based thermography (CTT) for ablation zone prediction in microwave ablation (MWA). METHODS: CTT was investigated during MWA in an in vivo porcine liver. For CTT, serial volume scans were acquired every 30 s during ablations and every 60 s immediately after MWA. After the procedure, contrast-enhanced computed tomography (CECT) was performed. After euthanasia, the liver was removed for sampling and further examination. Color-coded CTT maps were created for visualization of ablation zones, which were compared with both CECT and macroscopy. Average CT attenuation values in Hounsfield units (HU) were statistically correlated with temperatures using Spearman's correlation coefficient. CTT was retrospectively evaluated in one patient who underwent radiofrequency ablation (RFA) treatment of renal cell carcinoma. RESULTS: A significant correlation between HU and temperature was found with r = - 0.77 (95% confidence interval (CI), - 0.89 to - 0.57) and p < 0.001. Linear regression yielded a slope of - 1.96 HU/°C (95% CI, - 2.66 to - 1.26). Color-coded CTT maps provided superior visualization of ablation zones. CONCLUSION: Our results show that CTT allows visualization of the ablation area and measurement of its size and is feasible in patients, encouraging further exploration in a clinical setting. CRITICAL RELEVANCE STATEMENT: CT-based thermography research software allows visualization of the ablation zone and is feasible in patients, encouraging further exploration in a clinical setting to assess risk reduction of local recurrence.

Final-year medical students' perspective: a survey on the use of computed tomography in sepsis.

OBJECTIVES: To determine the perspective of final-year medical students on the use of computed tomography (CT) in patients with sepsis. METHODS: A total of 207 questionnaires were distributed to final-year medical students at a large university medical center, and 113 returned questionnaires met the criteria for inclusion in the analysis. Questions referred to sepsis guidelines, CT indications, and the use of contrast agents. Control variables included a level of practical experience as a final-year student (trimester of student's practical year) and previous radiological experience. Statistical hypothesis tests such as the Mann-Whitney U test and chi-square test were performed. RESULTS: The majority of participating students, 85% (n = 91/107), considered a Systemic Organ Failure Assessment (SOFA) score ≥ 2 as a diagnostic criterion for sepsis. The presence of ≥ 2 positive systemic inflammatory response syndrome (SIRS) criteria was considered relevant for diagnosing sepsis by 34% (n = 34/100). Ninety-nine percent (n = 64/65) of the participants who fully agreed with a SOFA score ≥ 2 being relevant for diagnosing sepsis would also use it as an indication for a CT scan. Seventy-six percent (n = 78/103) of the students rated a known severe allergic reaction to contrast agents as an absolute contraindication for its administration. Ninety-five percent (n = 78/82) considered radiation exposure as problematic in CT examinations, especially in repeat CTs. CONCLUSION: Most final-year medical students were familiar with the sepsis criteria. Still, some referred to outdated diagnostic criteria. Participants saw the ability to plan further patient management based on CT as a major benefit. Most participants were aware of radiation as a risk of CT. CRITICAL RELEVANCE STATEMENT: More detailed knowledge of CT in septic patients should be implemented in the medical curriculum. Retraining of medical students could help increase student confidence potentially improving patient care. KEY POINTS: 1. Whereas the majority of final-year medical students were familiar with sepsis criteria, some referred to outdated diagnostic criteria. 2. Participants saw the ability to plan further patient management based on CT as a major benefit. 3. Most participants were aware of radiation as a risk of CT.

Interdisciplinary perspectives on computed tomography in sepsis: survey among medical doctors at a large university medical center.

OBJECTIVES: This study aims to describe physicians' perspectives on the use of computed tomography (CT) in patients with sepsis. METHODS: In January 2022, physicians of a large European university medical center were surveyed using a web-based questionnaire asking about their views on the role of CT in sepsis. A total of 371 questionnaires met the inclusion criteria and were analyzed using work experience, workplace, and medical specialty of physicians as variables. Chi-square tests were performed. RESULTS: Physicians considered the ability to detect an unknown focus as the greatest benefit of CT scans in sepsis (70.9%, n = 263/371). Two clinical criteria - "signs of decreased vigilance" (89.2%, n = 331/371) and "increased catecholamine demand" (84.7%, n = 314/371) - were considered highly relevant for a CT request. Elevated procalcitonin (82.7%, n = 307/371) and lactate levels (83.6%, n = 310/371) were consistently found to be critical laboratory values to request a CT. As long as there is evidence of infection in one organ region, most physicians (42.6%, n = 158/371) would order a CT scan based on clinical assessment. Combined examination of the chest, abdomen, and pelvis was favored (34.8%, n = 129/371) in cases without clinical clues of an infection source. A time window of ≥ 1-6 h was preferred for both CT examinations (53.9%, n = 200/371) and CT-guided interventions (59.3%, n = 220/371) in patients with sepsis. CONCLUSION: Despite much consensus, there are significant differences in attitudes towards the use of CT in septic patients among physicians from different workplaces and medical specialties. Knowledge of these perspectives may improve patient management and interprofessional communication. KEY POINTS: Despite interdisciplinary consensus on the use of CT in sepsis, statistically significant differences in the responses are apparent among physicians from different workplaces and medical specialties. The detection of a previously unknown source of infection and the ability to plan interventions and/or surgery based on CT findings are considered key advantages of CT in septic patients. Timing of CT reflects the requirements of specific disciplines.

Evaluation of Different Registration Algorithms to Reduce Motion Artifacts in CT-Thermography (CTT).

Computed tomography (CT)-based Thermography (CTT) is currently being investigated as a non-invasive temperature monitoring method during ablation procedures. Since multiple CT scans with defined time intervals were acquired during this procedure, interscan motion artifacts can occur between the images, so registration is required. The aim of this study was to investigate different registration algorithms and their combinations for minimizing inter-scan motion artifacts during thermal ablation. Four CTT datasets were acquired using microwave ablation (MWA) of normal liver tissue performed in an in vivo porcine model. During each ablation, spectral CT volume scans were sequentially acquired. Based on initial reconstructions, rigid or elastic registration, or a combination of these, were carried out and rated by 15 radiologists. Friedman's test was used to compare rating results in reader assessments and revealed significant differences for the ablation probe movement rating only (p = 0.006; range, 5.3-6.6 points). Regarding this parameter, readers assessed rigid registration as inferior to other registrations. Quantitative analysis of ablation probe movement yielded a significantly decreased distance for combined registration as compared with unregistered data. In this study, registration was found to have the greatest influence on ablation probe movement, with connected registration being superior to only one registration process.

Missed Radiological Diagnosis of Otosclerosis in High-Resolution Computed Tomography of the Temporal Bone-Retrospective Analysis of Imaging, Radiological Reports, and Request Forms.

Objectives: Several studies reported low detection rates of otosclerosis in high-resolution computed tomography (HRCT), especially when the scans were reviewed by non-specialized general radiologists. In the present study, we conducted a retrospective review of the detection of otosclerosis in HRCT by general radiologists and the impact of inadequately filled radiological request forms on the detection rate. Methods: Retrospective analysis of hospital records, HRCT reports, and radiological referral notes of 40 patients who underwent stapedotomy surgery for otosclerosis. HRCT imaging data sets were retrospectively reviewed by a blinded experienced neuroradiologist, whose reading served as the gold standard. Results: General radiologists reading HRCT scans had an overall detection rate of otosclerosis of 36.1% in this cohort (13 of 36 available HRCT reports). The neuroradiologist had a much higher detection rate of 82.5% (33 of 40 cases). Interobserver agreement between the general radiologists and the subspecialist neuroradiologist was poor (Cohen's kappa κ = 0.26). General radiologists missed the diagnosis in 15 of the 33 CT-positive scans, corresponding to a missed diagnosis rate of 45.4%. There was a highly significant association between a missed diagnosis and the lack of an explicitly mentioned clinical suspicion of otosclerosis in the request forms (Pearson's chi-squared test, p < 0.005). Conclusion: The diagnosis of otosclerosis is frequently missed by radiologists on HRCT scans of the temporal bone in a clinical setting. Possible reasons include a relative lack of experience of general radiologists with temporal bone imaging as well as the failure of clinicians to unambiguously communicate their suspicion of otosclerosis.

Body computed tomography in sepsis: predictors of CT findings and patient outcomes in a retrospective medical ICU cohort study.

BACKGROUND: Sepsis is a life-threatening condition that requires immediate focus identification and control. However, international sepsis guidelines do not provide information on imaging choice. PURPOSE: To identify predictors of CT findings and patient outcomes in a population of septic patients from a medical ICU. MATERIAL AND METHODS: A full-text search in the radiological information system (RIS) retrieved 227 body CT examinations conducted to identify infectious sources in 2018. CT reports were categorized according to identified foci and their diagnostic certainty. Diagnostic accuracy of CT was compared to microbiological results. Clinical and laboratory information was gathered. Statistical analysis was performed using nonparametric tests and logistic regression analysis. RESULTS: CT revealed more positive infectious foci 52.4% (n = 191/227) than microbiological tests 39.3% (n = 79/201). There were no significant differences between focus-positive CT scans with regard to positive microbiological testing (p = 0.32). Sequential organ failure assessment (SOFA) scores were slightly but nonsignificantly higher in patients with a focus-positive CT, odds ratio (OR) = 0.999 (95% CI 0.997-1.001) with p = 0.52. Among C-reactive protein (CRP), procalcitonin (PCT), and leukocytes, in focus-positive versus focus-negative CT scans, CRP showed a minor but statistically significant elevation in the group with focus-positive CT scans (OR = 1.004, 95% CI = 1.000-1.007, p = 0.04). No significant association was found for PCT (OR = 1.007, 95% CI = 0.991-1.023; p = 0.40) or leukocytes (OR = 1.003, 95% CI = 0.970-1.038; p = 0.85). In 33.5% (n = 76/227) of cases, the CT findings had at least one therapeutic consequence. In 81.6% (n = 62/76), the CT findings resulted in one consequence, in 14.5% (n = 11/76) in two consequences, and in 3.9% (n = 3/76) in three consequences. There was no significant association between focus-positive CT scans and mortality (p = 0.81). CONCLUSION: In this population of septic patients in medical intensive care, microbiological analysis complemented CT findings. Both clinical and laboratory parameters were not predictive of CT findings. While therapeutic consequences of CT findings in this study population underline the role of CT for decision making in septic patients, CT findings do not predict patient outcomes in this retrospective analysis.

Cerebrovascular Events in Suspected Sepsis: Retrospective Prevalence Study in Critically Ill Patients Undergoing Full-Body Computed Tomography.

Purpose: This study aimed at retrospectively evaluating full-body computed tomography (CT) examinations for the prevalence of cerebrovascular events in patients with suspected sepsis treated in the intensive care unit (ICU). Methods: All full-body CT examinations, i.e., both cranial CT (cCT) and body CT including chest, abdomen and pelvis, for focus search in septic patients over a 12-months period were identified from three ICUs, using full-text search. From this retrospective cohort, we fully analyzed 278 cCT examinations for the occurrence of acute cerebral findings. All acute cerebrovascular events were independently reviewed by two blinded readers. Clinical and laboratory findings were extracted. The data were statistically analyzed using contingency tests. Results: In our population of patients with suspected sepsis, 10.8% (n = 30/278) were identified to have major cerebral events, including 7.2% (n = 20/278) major cerebrovascular events and 4.3% (n = 12/278) generalized parenchymal damage. 13.4% (n = 22/163) of patients with a severe coma as compared with non-severe coma, 4.4% (n = 3/68), showed a major cerebral event (p = 0.04). Patients referred from the cardiology/nephrology ICU ward showed major cerebral events in 16.3% (n = 22/135), as compared with 4.9% (n = 3/61) in patients from pulmonary ICU and 6.1% (n = 5/82) major cerebral events with surgical referral (p = 0.02). Conclusion: Our study provides further evidence that septic patients may suffer from cerebral events with relevance to their prognosis. Severe coma and the referring ward were associated with acute cerebral conditions. Full-body CT has the advantage of both detecting of septic foci and possibly identifying ischemic or hemorrhagic stroke in this vulnerable patient population.

Visualizing patterns of intervertebral disc damage with dual-energy computed tomography: assessment of diagnostic accuracy in an ex vivo spine biophantom.

BACKGROUND: Previously, dual-energy computed tomography (DECT) has been established for imaging spinal fractures as an alternative modality to magnetic resonance imaging (MRI). PURPOSE: To analyze the diagnostic accuracy of DECT in visualizing intervertebral disc (IVD) damage. MATERIAL AND METHODS: The lumbar spine of a Great Dane dog was used as an ex vivo biophantom. DECT was performed as sequential volume technique on a single-source CT scanner. IVDs were imaged before and after an injection of sodium chloride solution and after anterior discectomy in single-source sequential volume DECT technique using 80 and 135 kVp. Chondroitin/Collagen maps (cMaps) were reconstructed at 1 mm and compared with standard CT. Standardized regions of interest (ROI) were placed in the anterior anulus fibrosus, nucleus pulposus, and other sites. Three blinded readers classified all images as intact disc, nucleus lesion, or anulus lesion. Additionally, clinical examples from patients with IVD lesions were retrospectively identified from the radiological database. RESULTS: Interrater reliability was almost perfect with a Fleiss kappa of 0.833 (95% confidence interval [CI] 0.83-0.835) for DECT, compared with 0.780 (95% CI 0.778-0.782) for standard CT. For overall detection accuracy of IVD, DECT achieved 91.0% sensitivity (95% CI 83.6-95.8) and 92.0% specificity (95% CI 80.8-97.8). Standard CT showed 91.0% sensitivity (95% CI 83.6-95.8) and 78.0% specificity (95% CI 64.0-88.5). CONCLUSION: DECT reliably identified IVD damage in an ex vivo biophantom. Clinical examples of patients with different lesions illustrate the accurate depiction of IVD microstructure. These data emphasize the diagnostic potential of DECT cMaps.

Atypical presentation of a locally advanced hepatocellular carcinoma: Extensive workup of an incidental finding on computed tomography performed for planning of transcatheter aortic valve implantation.

This case report presents the diagnostic workup of liver malignancy incidentally detected in a 72-year-old male patient on routine body computed tomography angiography (CTA) performed for planning transcatheter aortic valve implantation (TAVI). The patient initially presented to an outside hospital with chest discomfort, where routine diagnostic procedures in the emergency room revealed grade III aortic valve stenosis. Routine CTA for TAVI planning in our department then revealed tumor thrombosis of the portal vein suspicious for hepatic malignancy. In contrast-enhanced ultrasound (CEUS) only the left hepatic lobe was inhomogeneously transformed with early arterial contrast enhancement. Magnetic resonance imaging (MRI) confirmed a primary hepatic malignancy involving the left liver. Transcutaneous biopsy with ultrasound guidance established the diagnosis of hepatocellular carcinoma (HCC). Incidental findings may be of prognostic relevance for the patient and in a number of cases, TAVI can be a prerequisite for the appropriate therapy.

Age-dependent microstructural changes of the intervertebral disc: a validation of proteoglycan-sensitive spectral CT.

OBJECTIVE: To analyze the two major components of the intervertebral disc (IVD) in an ex vivo phantom, as well as age-related changes in patients. METHODS: Collagen and chondroitin sulfate were imaged at different concentrations in agar solution. Age-related changes in disc density were retrospectively analyzed in normal-appearing discs in dual-energy computed tomography (DECT) images from a patient cohort with various spinal pathologies (n = 136). All computed tomography (CT) scans were acquired using single-source DECT at 80 and 135 kVp with automatic exposure calculation. In 136 patients, the attenuation of normal-appearing discs on collagen/chondroitin maps (cMaps) correlated with the patients' age with Pearson's r using standardized regions of interest in the anterior anulus fibrosus (AAF) and nucleus pulposus (NP). RESULTS: DECT collagen mapping revealed concentration-dependent Hounsfield units (HU) of IVD components. For collagen, we found Pearson's r = 0.9610 (95% CI 0.6789-0.9959), p = 0.0023 at 120 kVe, and r = 0.8824 (95% CI 0.2495-0.9871), p = 0.0199 in cMap. For chondroitin sulfate, Pearson's r was 0.9583 (95% CI 0.6603-0.9956), p = 0.0026 at 120 kVp, and r = 0.9646 (95% CI 0.7044-0.9963), p = 0.0019 in cMap. Analysis of normal-appearing IVDs revealed an inverse correlation of density with age in the AAF: Pearson's r = - 0.2294 at 135 kVp (95% CI - 0.4012 to - 0.04203; p=0.0141) and r = - 0.09341 in cMap (95% CI - 0.2777 to 0.09754; p = 0.0003). In the NP, age and density did not correlate significantly at 135 kVp (p = 0.9228) and in cMap (p = 0.3229). CONCLUSIONS: DECT-based collagen mapping allows microstructural analysis of the two main intervertebral disc components-collagen and chondroitin sulfate. IVD density declines with age, presumably due to a reduction in collagen and chondroitin sulfate content. Age-related alterations of disc microstructure appear most pronounced in the AAF. KEY POINTS: • DECT-based collagen mapping allows precise analysis of the two main intervertebral disc components-collagen and chondroitin sulfate. • Intervertebral disc (IVD) density declines with age, presumably due to a reduction in collagen and chondroitin sulfate content. • Age-related alterations of disc microstructure are most pronounced in the anterior anulus fibrosus (AAF).

Multiple liver perforations: complication of an outpatient liposuction procedure.

We report on a 29-year-old woman who presented with abdominal right upper quadrant pain after an outpatient liposuction procedure. A contrast-enhanced computed tomography scan revealed 4 hepatic perforation tracts with subcapsular liver hematoma and hematoperitoneum. The patient was treated by intravenous tranexamic acid and isotonic fluids and monitored on an intensive care unit. No intervention or surgery was necessary during her hospital stay. Follow-up imaging after 3 days using contrast-enhanced ultrasound still showed the perforation tracts in the liver but no expansion of subcapsular hematoma. After 7 days, the patient was discharged home with stable hemoglobin and reduced pain. Liver perforation is a rare complication of liposuction procedures. In patients with abdominal pain after liposuction, contrast-enhanced imaging studies should be performed to identify and characterize solid organ injury. Teams with expertise in angiography and visceral surgery need to be on standby.

Computed tomography for detection of septic foci: Retrospective analysis of patients presenting to the emergency department.

OBJECTIVE: Sepsis is defined as organ dysfunction due to severe infection. Septic patients face a significant mortality risk. Thus, timely recognition with prompt focus identification and control are essential. This study aims to determine the current role of computed tomography (CT) in the diagnostic workup of septic patients. METHODS: We retrospectively identified 357 patients in the emergency department (ED) of a large university center with suspected sepsis in a two-year period. A total of 132 patients underwent CT scanning within 72 h of admission. Patients were characterized by clinical and laboratory findings. CT reports were categorized and matched with clinical data. RESULTS: Of 357 ED patients with suspected sepsis, 37.0% (132/357) underwent CT imaging within 72 h. The most commonly identified septic foci in CT were chest 38.6% (49/127), abdomen 22.0% (28/127) and genitourinary tract 20.5% (26/127) in descending order. The focus detection rate was 76.5% per patient with a concurrent number-needed-to-scan of 1.31. Contrast medium administration in CT did not improve focus detection rate (p = 0.631) or diagnostic confidence in this patient population (p = 0.432). CT had a positive predictive value of 81.82% (CI 76.31 to 86.28%) in predicting the focus of the discharge diagnosis. Follow-up imaging in patients with unclear focus reveals a new focus in 39.5% of patients. CONCLUSIONS: Our investigation of the role of CT in ED patients with suspected sepsis indicated a high positive predictive value for CT with regard to the discharge diagnosis. Repeat imaging may help identify further septic foci in a subgroup with persistently unclear focus. Use of contrast medium seems less relevant for focus detection than expected, as it did not increase diagnostic confidence.

Pseudo aneurysm of the uterine artery with arteriovenous fistula after cesarean section: A rare but sinister cause of delayed postpartum hemorrhage.

Pseudoaneurysm of the uterine artery is a rare complication of cesarean section. Delayed diagnosis and management may result in rapid and catastrophic postpartum hemorrhage and may necessitate hysterectomy or can even be fatal. A 28-year-old woman (gravida I, para I) presented with delayed postpartum hemorrhage 10 days after emergency cesarean section. Using transabdominal and transvaginal Color Doppler sonography, we detected a pseudoaneurysm in the posterior uterine wall, which was successfully treated with selective embolization distal and proximal to the lesion with platinum coils. In patients with delayed postpartum hemorrhage-especially after cesarean section-the rare possibility of uterine artery pseudoaneurysm must be kept in mind.

The role of body computed tomography in hospitalized patients with obscure infection: Retrospective consecutive cohort study.

OBJECTIVE: Patients with severe infection or sepsis require fast identification of the focus and prompt eradication. This study aims at investigating the role of body computed tomography (CT) and identifying outcome predictors in a general ward setting of patients with obscure infection. METHODS: We retrospectively identified 196 consecutive body CTs acquired in 179 patients with obscure infection, i.e. severe infection or sepsis from general wards with unclear focus, over 12-months in the year 2018. Reports were extracted using a full-text search in the radiological information system (RIS) of a large university medical center. CT reports were classified according to diagnostic confidence of the reader (i.e. certain, likely, possible, no focus), and correlated with clinical and laboratory parameters. The discharge diagnosis was set as the diagnostic reference standard. Contingency tables were prepared for statistical analysis with Chi-squared test amongst other analyses and the calculation of AUC statistics. RESULTS: In 133 out of 196 (67.9 %) body CTs from general wards with severe infection or sepsis, body CT identified an infectious focus. 90 % of the infections were located in the chest, abdomen, and genitourinary tract, in descending order. In 76.5 % (150 of 196) of examinations, CT correctly predicted the final infectious source. The positive predictive value (PPV) of a CT-detected focus was 84.2 % (95 % CI 79.0%-88.3%). A high diagnostic confidence of the reader resulted in a PPV of 96.4 % (95 % CI 87.4%-99.1%) while a low confidence resulted in a PPV of 63.3 % (95 % CI 48.2%-76.3%). CONCLUSION: In patients with obscure infection treated in general wards, body CT detects the infectious source with a high positive predictive value. Focus detection accuracy highly depends on the diagnostic confidence of the CT reader.

Computed Tomography Thermography for Ablation Zone Prediction in Microwave Ablation and Cryoablation: Advantages and Challenges in an Ex Vivo Porcine Liver Model.

PURPOSE: The aim of this study was to investigate the diagnostic accuracy of computed tomography (CT) for the prediction of ablation zones from microwave ablation (MWA) and cryoablation (CA) in an ex vivo porcine liver model. METHODS: Sequential (30 seconds) CT scans were acquired during and after MWA and CA in an ex vivo porcine liver model. We generated 120-kVp equivalent reconstructions of generic dual-energy CT data sets, and comprehensive region-of-interest measurements were statistically correlated with invasive temperature monitoring using Pearson correlation coefficient. Binary logistic regression was performed for prediction of successful ablation. RESULTS: With the use of pooled data from 6 lesions in 2 separate experiments, correlation analysis of attenuation in Hounsfield units (HU) and temperature yielded r = -0.79 [confidence interval (CI), -0.85 to -0.71] for MWA and r = 0.62 (CI, 0.55 to 0.67) for CA.For MWA, there was a linear association between attenuation and temperature up to 75°C; thus, linear regression yielded a slope of -2.00 HU/°C (95% CI, -1.58 to -2.41). For CA, a linear association between attenuation and temperature was observed in the cooling phase with a slope of 2.11 HU/°C (95% CI, 1.79 to 2.58). In MWA treatment, binary logistic regression separated less than 70°C and greater than 70°C with 89.2% accuracy. Within the ice ball, temperatures above and below -20°C were distinguished with 65.3% accuracy. CONCLUSIONS: Our experiments reveal several difficulties in predicting ablation zone temperature from CT attenuation. Microwave ablation leads to gas production in the tissue, which degrades the accuracy of noninvasive temperature measurement, especially at higher temperatures. In CA, CT thermometry is limited by ice ball formation, which leads to homogeneous attenuation, nearly independent of temperature. Further research is needed to define the role of CT thermography in ablation zone monitoring in liver malignancies.

Successful aspiration thrombectomy in a patient with submassive, intermediate-risk pulmonary embolism following COVID-19 pneumonia.

A 64-year-old female patient presented with severe dyspnea shortly after apparent recovery from COVID-19 disease. Chest computed tomography revealed central pulmonary embolism and ultrasonography showed a deep vein thrombosis of her right leg. The patient was tachycardiac with evidence of right ventricular strain on echocardiography. An interdisciplinary decision for interventional therapy was made. Angiographic aspiration thrombectomy resulted in a significant reduction of thrombus material and improved flow in the pulmonary arteries and immediate marked clinical improvement and subsequent normalization of functional echocardiographic parameters. This case adds to the emerging evidence for severe thromboembolic complications following COVID-19 and suggests aspiration thrombectomy can be considered in pulmonary embolism of intermediate risk.

Analyzing Nicotinamide Adenine Dinucleotide Phosphate Oxidase Activation in Aging and Vascular Amyloid Pathology.

In aging individuals, both protective as well as regulatory immune functions are declining, resulting in an increased susceptibility to infections as well as to autoimmunity. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2-deficiency in immune cell subsets has been shown to be associated with aging. Using intravital marker-free NAD(P)H-fluorescence lifetime imaging, we have previously identified microglia/myeloid cells and astrocytes as main cellular sources of NADPH oxidase (NOX) activity in the CNS during neuroinflammation, due to an overactivation of NOX. The overactivated NOX enzymes catalyze the massive production of the highly reactive [Formula: see text] which initiates in a chain reaction the overproduction of diverse reactive oxygen species (ROS). Age-dependent oxidative distress levels in the brain and their cellular sources are not known. Furthermore, it is unclear whether in age-dependent diseases oxidative distress is initiated by overproduction of ROS or by a decrease in antioxidant capacity, subsequently leading to neurodegeneration in the CNS. Here, we compare the activation level of NOX enzymes in the cerebral cortex of young and aged mice as well as in a model of vascular amyloid pathology. Despite the fact that a striking change in the morphology of microglia can be detected between young and aged individuals, we find comparable low-level NOX activation both in young and old mice. In contrast, aged mice with the human APPE693Q mutation, a model for cerebral amyloid angiopathy (CAA), displayed increased focal NOX overactivation in the brain cortex, especially in tissue areas around the vessels. Despite activated morphology in microglia, NOX overactivation was detected only in a small fraction of these cells, in contrast to other pathologies with overt inflammation as experimental autoimmune encephalomyelitis (EAE) or glioblastoma. Similar to these pathologies, the astrocytes majorly contribute to the NOX overactivation in the brain cortex during CAA. Together, these findings emphasize the role of other cellular sources of activated NOX than phagocytes not only during EAE but also in models of amyloid pathology. Moreover, they may strengthen the hypothesis that microglia/monocytes show a diminished potential for clearance of amyloid beta protein.

Time lapse in vivo microscopy reveals distinct dynamics of microglia-tumor environment interactions-a new role for the tumor perivascular space as highway for trafficking microglia.

Microglial cells are critical for glioma growth and progression. However, only little is known about intratumoral microglial behavior and the dynamic interaction with the tumor. Currently the scarce understanding of microglial appearance in malignant gliomas merely originates from histological studies and in vitro investigations. In order to understand the pattern of microglia activity, motility and migration we designed an intravital study in an orthotopic murine glioma model using CX3CR1-eGFP(GFP/wt) mice. We analysed the dynamics of intratumoral microglia accumulation and activity, as well as microglia/tumor blood vessel interaction by epi-illumination and 2-photon laser scanning microscopy. We further investigated cellular and tissue function, including the enzyme activity of intratumoral and microglial NADPH oxidase measured by in vivo fluorescence lifetime imaging. We identified three morphological phenotypes of tumor-associated microglia cells with entirely different motility patterns. We found that NADPH oxidase activation is highly divergent in these microglia subtypes leading to different production levels of reactive oxygen species (ROS). We observed that microglia motility is highest within the perivascular niche, suggesting relevance of microglia/tumor blood vessel interactions. In line, reduction of tumor blood vessels by antivascular therapy confirmed the relevance of the tumor vessel compartment on microglia biology in brain tumors. In summary, we provide new insights into in vivo microglial behavior, regarding both morphology and function, in malignant gliomas. GLIA 2016;64:1210-1226.