CT venography for the diagnosis of postpartum venous thromboembolism: a prospective multi-center cohort study.

OBJECTIVES: To assess the role of CT venography (CTV) in the diagnosis of venous thromboembolism (VTE) during the postpartum period. MATERIALS AND METHODS: This multicenter prospective cohort study was conducted between April 2016 and April 2020 in 14 university hospitals. All women referred for CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE) within the first 6 weeks postpartum were eligible. All CTPAs were performed on multidetector CT machines with the usual parameters and followed by CTV of the abdomen, pelvis, and proximal lower limbs. On-site reports were compared to expert consensus reading, and the added value of CTV was assessed for both. RESULTS: The final study population consisted of 123 women. On-site CTPA reports mentioned PE in seven women (7/123, 5.7%), all confirmed following expert consensus reading, three involving proximal pulmonary arteries and four limited to distal arteries. Positive CTV was reported on-site in nine women, five of whom had negative and two indeterminate CTPAs, bringing the VTE detection rate to 11.4% (14/123) (95%CI: 6.4-18.4, p = 0.03). Expert consensus reading confirmed all positive on-site CTV results, but detected a periuterine vein thrombosis in an additional woman who had a negative CTPA, increasing the VTE detection rate to 12.2% (15/123) (95%CI: 7.0-19.3, p = 0.008). Follow-up at 3 months revealed no adverse events in this woman, who was left untreated. Median Dose-Length-Product was 117 mGy.cm for CTPA and 675 mGy.cm for CTPA + CTV. CONCLUSION: Performing CTV in women suspected of postpartum PE doubles the detection of venous thromboembolism, at the cost of increased radiation exposure. CLINICAL RELEVANCE STATEMENT: CTV can help in the decision-making process concerning curative anticoagulation in women with suspected postpartum PE, particularly those whose CTPA results are indeterminate or whose PE is limited to the subsegmental level. KEY POINTS: Postpartum women are at risk of pulmonary embolism, and CT pulmonary angiography can give equivocal results. CT venography (CTV) positivity increased the venous thromboembolism detection rate from 5.7 to 11.4%. CTV may help clinical decision-making, especially in women with indeterminate CTPA results or subsegmental emboli.

Strategies to safely rule out pulmonary embolism in COVID-19 outpatients: a multicenter retrospective study.

OBJECTIVES: The objective was to define a safe strategy to exclude pulmonary embolism (PE) in COVID-19 outpatients, without performing CT pulmonary angiogram (CTPA). METHODS: COVID-19 outpatients from 15 university hospitals who underwent a CTPA were retrospectively evaluated. D-Dimers, variables of the revised Geneva and Wells scores, as well as laboratory findings and clinical characteristics related to COVID-19 pneumonia, were collected. CTPA reports were reviewed for the presence of PE and the extent of COVID-19 disease. PE rule-out strategies were based solely on D-Dimer tests using different thresholds, the revised Geneva and Wells scores, and a COVID-19 PE prediction model built on our dataset were compared. The area under the receiver operating characteristics curve (AUC), failure rate, and efficiency were calculated. RESULTS: In total, 1369 patients were included of whom 124 were PE positive (9.1%). Failure rate and efficiency of D-Dimer > 500 µg/l were 0.9% (95%CI, 0.2-4.8%) and 10.1% (8.5-11.9%), respectively, increasing to 1.0% (0.2-5.3%) and 16.4% (14.4-18.7%), respectively, for an age-adjusted D-Dimer level. D-dimer > 1000 µg/l led to an unacceptable failure rate to 8.1% (4.4-14.5%). The best performances of the revised Geneva and Wells scores were obtained using the age-adjusted D-Dimer level. They had the same failure rate of 1.0% (0.2-5.3%) for efficiency of 16.8% (14.7-19.1%), and 16.9% (14.8-19.2%) respectively. The developed COVID-19 PE prediction model had an AUC of 0.609 (0.594-0.623) with an efficiency of 20.5% (18.4-22.8%) when its failure was set to 0.8%. CONCLUSIONS: The strategy to safely exclude PE in COVID-19 outpatients should not differ from that used in non-COVID-19 patients. The added value of the COVID-19 PE prediction model is minor. KEY POINTS: • D-dimer level remains the most important predictor of pulmonary embolism in COVID-19 patients. • The AUCs of the revised Geneva and Wells scores using an age-adjusted D-dimer threshold were 0.587 (95%CI, 0.572 to 0.603) and 0.588 (95%CI, 0.572 to 0.603). • The AUC of COVID-19-specific strategy to rule out pulmonary embolism ranged from 0.513 (95%CI: 0.503 to 0.522) to 0.609 (95%CI: 0.594 to 0.623).

Post hoc Analysis of Clinical Outcomes in Placebo- and Pirfenidone-Treated Patients with IPF Stratified by BMI and Weight Loss.

BACKGROUND: Weight loss is frequently reported in patients with idiopathic pulmonary fibrosis (IPF) and may be associated with worse outcomes in these patients. OBJECTIVE: The aim of this study was to investigate the relationships between body mass index (BMI) and weight loss, and outcomes over 1 year in patients with IPF. METHODS: Data were included from placebo patients enrolled in ASCEND (NCT01366209) and CAPACITY (NCT00287716 and NCT00287729), and all patients in INSPIRE (NCT00075998) and RIFF Cohort A (NCT01872689). An additional analysis included data from pirfenidone-treated patients. Outcomes (annualized change in percent predicted forced vital capacity [%FVC], percent predicted carbon monoxide diffusing capacity, 6-min walk distance, St. George's Respiratory Questionnaire total score, hospitalization, mortality, and serious adverse events) were analyzed by baseline BMI (<25 kg/m2, 25 kg/m2-<30 kg/m2, or ≥30 kg/m2) and annualized percent change in body weight (no loss, >0-<5% loss, or ≥5% loss). RESULTS: Placebo-treated patients with a baseline BMI <25 kg/m2 or annualized weight loss may experience worse outcomes versus those with a baseline BMI ≥25 kg/m2 or no weight loss. The proportion of placebo-treated patients who experienced a relative decline of ≥10% in %FVC or death up to 1 year post-randomization was highest in patients with a baseline BMI <25 kg/m2. Pirfenidone-treated patients with an annualized weight loss ≥5% may also experience worse outcomes versus those with no weight loss. CONCLUSIONS: Patients with a baseline BMI <25 kg/m2 or annualized weight loss of >0-<5% or ≥5% may experience worse outcomes over 1 year versus those with a baseline BMI ≥25 kg/m2 or no weight loss.

SARS-CoV-2-Induced ARDS Associates with MDSC Expansion, Lymphocyte Dysfunction, and Arginine Shortage.

PURPOSE: The SARS-CoV-2 infection can lead to a severe acute respiratory distress syndrome (ARDS) with prolonged mechanical ventilation and high mortality rate. Interestingly, COVID-19-associated ARDS share biological and clinical features with sepsis-associated immunosuppression since lymphopenia and acquired infections associated with late mortality are frequently encountered. Mechanisms responsible for COVID-19-associated lymphopenia need to be explored since they could be responsible for delayed virus clearance and increased mortality rate among intensive care unit (ICU) patients. METHODS: A series of 26 clinically annotated COVID-19 patients were analyzed by thorough phenotypic and functional investigations at days 0, 4, and 7 after ICU admission. RESULTS: We revealed that, in the absence of any difference in demographic parameters nor medical history between the two groups, ARDS patients presented with an increased number of myeloid-derived suppressor cells (MDSC) and a decreased number of CD8pos effector memory cell compared to patients hospitalized for COVID-19 moderate pneumonia. Interestingly, COVID-19-related MDSC expansion was directly correlated to lymphopenia and enhanced arginase activity. Lastly, T cell proliferative capacity in vitro was significantly reduced among COVID-19 patients and could be restored through arginine supplementation. CONCLUSIONS: The present study reports a critical role for MDSC in COVID-19-associated ARDS. Our findings open the possibility of arginine supplementation as an adjuvant therapy for these ICU patients, aiming to reduce immunosuppression and help virus clearance, thereby decreasing the duration of mechanical ventilation, nosocomial infection acquisition, and mortality.

Efficacy of Chest CT for COVID-19 Pneumonia Diagnosis in France.

Background The role and performance of chest CT in the diagnosis of the coronavirus disease 2019 (COVID-19) pandemic remains under active investigation. Purpose To evaluate the French national experience using chest CT for COVID-19, results of chest CT and reverse transcription polymerase chain reaction (RT-PCR) assays were compared together and with the final discharge diagnosis used as the reference standard. Materials and Methods A structured CT scan survey (NCT04339686) was sent to 26 hospital radiology departments in France between March 2, 2020, and April 24, 2020. These dates correspond to the peak of the national COVID-19 epidemic. Radiology departments were selected to reflect the estimated geographic prevalence heterogeneities of the epidemic. All symptomatic patients suspected of having COVID-19 pneumonia who underwent both initial chest CT and at least one RT-PCR test within 48 hours were included. The final discharge diagnosis, based on multiparametric items, was recorded. Data for each center were prospectively collected and gathered each week. Test efficacy was determined by using the Mann-Whitney test, Student t test, χ2 test, and Pearson correlation coefficient. P < .05 indicated a significant difference. Results Twenty-six of 26 hospital radiology departments responded to the survey, with 7500 patients entered; 2652 did not have RT-PCR test results or had unknown or excess delay between the RT-PCR test and CT. After exclusions, 4824 patients (mean age, 64 years ± 19 [standard deviation], 2669 male) were included. With final diagnosis as the reference, 2564 of the 4824 patients had COVID-19 (53%). Sensitivity, specificity, negative predictive value, and positive predictive value of chest CT in the diagnosis of COVID-19 were 2319 of 2564 (90%; 95% CI: 89, 91), 2056 of 2260 (91%; 95% CI: 91, 92), 2056 of 2300 (89%; 95% CI: 87, 90), and 2319 of 2524 (92%; 95% CI: 91, 93), respectively. There was no significant difference for chest CT efficacy among the 26 geographically separate sites, each with varying amounts of disease prevalence. Conclusion Use of chest CT for the initial diagnosis and triage of patients suspected of having coronavirus disease 2019 was successful. © RSNA, 2021 Online supplemental material is available for this article.

Study of Thoracic CT in COVID-19: The STOIC Project.

Background There are conflicting data regarding the diagnostic performance of chest CT for COVID-19 pneumonia. Disease extent at CT has been reported to influence prognosis. Purpose To create a large publicly available data set and assess the diagnostic and prognostic value of CT in COVID-19 pneumonia. Materials and Methods This multicenter, observational, retrospective cohort study involved 20 French university hospitals. Eligible patients presented at the emergency departments of the hospitals involved between March 1 and April 30th, 2020, and underwent both thoracic CT and reverse transcription-polymerase chain reaction (RT-PCR) testing for suspected COVID-19 pneumonia. CT images were read blinded to initial reports, RT-PCR, demographic characteristics, clinical symptoms, and outcome. Readers classified CT scans as either positive or negative for COVID-19 based on criteria published by the French Society of Radiology. Multivariable logistic regression was used to develop a model predicting severe outcome (intubation or death) at 1-month follow-up in patients positive for both RT-PCR and CT, using clinical and radiologic features. Results Among 10 930 patients screened for eligibility, 10 735 (median age, 65 years; interquartile range, 51-77 years; 6147 men) were included and 6448 (60%) had a positive RT-PCR result. With RT-PCR as reference, the sensitivity and specificity of CT were 80.2% (95% CI: 79.3, 81.2) and 79.7% (95% CI: 78.5, 80.9), respectively, with strong agreement between junior and senior radiologists (Gwet AC1 coefficient, 0.79). Of all the variables analyzed, the extent of pneumonia at CT (odds ratio, 3.25; 95% CI: 2.71, 3.89) was the best predictor of severe outcome at 1 month. A score based solely on clinical variables predicted a severe outcome with an area under the curve of 0.64 (95% CI: 0.62, 0.66), improving to 0.69 (95% CI: 0.6, 0.71) when it also included the extent of pneumonia and coronary calcium score at CT. Conclusion Using predefined criteria, CT reading is not influenced by reader's experience and helps predict the outcome at 1 month. ClinicalTrials.gov identifier: NCT04355507 Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Rubin in this issue.

Voxel-based mapping of five MR biomarkers in the wrist bone marrow.

OBJECTIVE: MRI is a reliable and accurate technique to characterize rheumatoid arthritis. The aim of this study was to provide voxel-by-voxel 3D maps of the proton density fat fraction (PDFF), the T1 of water (T1W), the T1 of fat (T1F), the T2* of water (T2*W), the T2* of fat (T2*F) in the wrist bone marrow. MATERIALS AND METHODS: The experiments were conducted on 14 healthy volunteers (mean age: 24 ± 4). The data were acquired at 1.5 T using two optimized four-echo 3D 1.2 × 1.2 × 1.2 mm3-isotropic spoiled gradient sequences. A repeatability study was carried out. The measurements were done using a homemade parametric viewer software. RESULTS: The inter-volunteer results were, on average: PDFF = 86 ± 3%, T1W = 441 ± 113 ms, T1F = 245 ± 19 ms, T2*W = 6 ± 1 ms and T2*F = 16 ± 3 ms. The coefficients of variation were for fat based biomarkers CVPDFF < 5%, CVT1F < 15% and CVT2*F < 10% in the repeatability study. DISCUSSION: The protocol and quantification tool proposed in this study provide high-resolution voxel-by-voxel 3D maps of five biomarkers in the wrist in less than 4 min of acquisition.

Imaging predictors of response to cardiac resynchronization therapy: left ventricular work asymmetry by echocardiography and septal viability by cardiac magnetic resonance.

AIMS: Left ventricular (LV) failure in left bundle branch block is caused by loss of septal function and compensatory hyperfunction of the LV lateral wall (LW) which stimulates adverse remodelling. This study investigates if septal and LW function measured as myocardial work, alone and combined with assessment of septal viability, identifies responders to cardiac resynchronization therapy (CRT). METHODS AND RESULTS: In a prospective multicentre study of 200 CRT recipients, myocardial work was measured by pressure-strain analysis and viability by cardiac magnetic resonance (CMR) imaging (n = 125). CRT response was defined as ≥15% reduction in LV end-systolic volume after 6 months. Before CRT, septal work was markedly lower than LW work (P < 0.0001), and the difference was largest in CRT responders (P < 0.001). Work difference between septum and LW predicted CRT response with area under the curve (AUC) 0.77 (95% CI: 0.70-0.84) and was feasible in 98% of patients. In patients undergoing CMR, combining work difference and septal viability significantly increased AUC to 0.88 (95% CI: 0.81-0.95). This was superior to the predictive power of QRS morphology, QRS duration and the echocardiographic parameters septal flash, apical rocking, and systolic stretch index. Accuracy was similar for the subgroup of patients with QRS 120-150 ms as for the entire study group. Both work difference alone and work difference combined with septal viability predicted long-term survival without heart transplantation with hazard ratio 0.36 (95% CI: 0.18-0.74) and 0.21 (95% CI: 0.072-0.61), respectively. CONCLUSION: Assessment of myocardial work and septal viability identified CRT responders with high accuracy.

Analysis of body mass index, weight loss and progression of idiopathic pulmonary fibrosis.

BACKGROUND: Nintedanib is an approved therapy for idiopathic pulmonary fibrosis (IPF). Some patients treated with nintedanib experience weight loss. Exploratory data suggest that low body mass index or weight loss are associated with worse outcomes in patients with IPF. We investigated whether BMI at baseline or weight loss over 52 weeks was associated with FVC decline, or influenced the effect of nintedanib, in patients with IPF. METHODS: Using pooled data from the two INPULSIS trials, we analysed the rate of decline in FVC (mL/yr) over 52 weeks in patients treated with nintedanib and placebo in subgroups by baseline BMI (< 25; ≥25 to < 30; ≥30 kg/m2) and by weight loss over 52 weeks (≤5; > 5%) using random coefficient regression. RESULTS: In the placebo group, the mean rate of FVC decline over 52 weeks was numerically greater in patients with lower baseline BMI (- 283.3 [SE 22.4], - 207.9 [20.9] and - 104.5 [21.4] in patients with BMI < 25 kg/m2, ≥25 to < 30 kg/m2 and ≥ 30 kg/m2, respectively). Nintedanib reduced the rate of FVC decline versus placebo in all subgroups by BMI, with a consistent treatment effect across subgroups (interaction p = 0.31). In the placebo group, the mean rate of FVC decline was numerically greater in patients with > 5% than ≤5% weight loss over 52 weeks (- 312.7 [SE 32.2] versus - 199.5 [SE 14.4] mL/year). Nintedanib reduced the rate of FVC decline versus placebo in both subgroups by weight loss, with a greater treatment effect in patients with > 5% weight loss (interaction p = 0.0008). The adverse event profile of nintedanib was similar across subgroups. CONCLUSIONS: In patients with IPF, lower BMI and weight loss may be associated with faster decline in FVC. Nintedanib reduces the rate of FVC decline both in patients who lose weight on treatment and those who do not. TRIAL REGISTRATION: ClinicalTrials.gov ; Nos. NCT01335464 and NCT01335477 ; URL: www.clinicaltrials.gov .

COVID-19 impact assessment on the French radiological centers: a nationwide survey.

PURPOSE: To determine the impact of the COVID-19 on the CT activities in French radiological centers during the epidemic peak. MATERIALS AND METHODS: A cross-sectional prospective CT scan survey was conducted between March 16 and April 12, 2020, in accordance with the local IRB. Seven hundred nine radiology centers were invited to participate in a weekly online survey. Numbers of CT examinations related to COVID-19 including at least chest (CTcovid) and whole chest CT scan activities (CTchest) were recorded each week. A sub-analysis on French departments was performed during the 4 weeks of the study. The impact of the number of RT-PCRs (reverse transcriptase polymerase chain reactions) on the CT workflow was tested using two-sample t test and Pearson's test. RESULTS: Five hundred seventy-seven structures finally registered (78%) with mean response numbers of 336 ± 18.9 (323; 351). Mean CTchest activity per radiologic structure ranged from 75.8 ± 133 (0-1444) on week 12 to 99.3 ± 138.6 (0-1147) on week 13. Mean ratio of CTcovid on CTchest varied from 0.36 to 0.59 on week 12 and week 14 respectively. There was a significant relationship between the number of RT-PCR performed and the number of CTcovid (r = 0.73, p = 3.10-16) but no link with the number of positive RT-PCR results. CONCLUSION: In case of local high density COVID-19, CT workflow is strongly modified and redirected to the management of these specific patients. KEY POINTS: • Over the 4-week survey period, 117,686 chest CT (CTtotal) were performed among the responding centers, including 61,784 (52%) CT performed for COVID-19 (CTcovid). • Across the country, the ratio CTcovid/CTtotal varied from 0.36 to 0.59 and depended significantly on the local epidemic density (p = 0.003). • In clinical practice, in a context of growing epidemic, in France, chest CT was used as a surrogate to RT-PCR for patient triage.

Pulmonary alveolar proteinosis.

PAP is an ultra-rare disease in which surfactant components, that impair gas exchange, accumulate in the alveolae. There are three types of PAP. The most frequent form, primary PAP, includes autoimmune PAP which accounts for over 90% of all PAP, defined by the presence of circulating anti-GM-CSF antibodies. Secondary PAP is mainly due to haematological disease, infections or inhaling toxic substances, while genetic PAP affects almost exclusively children. PAP is suspected if investigation for ILD reveals a crazy-paving pattern on chest CT scan, and is confirmed by a milky looking BAL that gives a positive PAS reaction indicating extracellular proteinaceous material. PAP is now rarely confirmed by surgical lung biopsy. WLL is still the first-line treatment, with an inhaled GM-CSF as second-line treatment. Inhalation has been found to be better than subcutaneous injections. Other treatments, such as rituximab or plasmapheresis, seem to be less efficient or ineffective. The main complications of PAP are due to infections by standard pathogens (Streptococcus, Haemophilus and Enterobacteria) or opportunistic pathogens such as mycobacteria, Nocardia, Actinomyces, Aspergillus or Cryptococcus. The clinical course of PAP is unpredictable and spontaneous improvement can occur. The 5-year actuarial survival rate is 95%.

Whole-Body CT after Motor Vehicle Crash: No Benefit after High-Energy Impact and with Normal Physical Examination.

Background Debate continues about the risks and benefits of systematic whole-body CT when no injury is clinically suspected. Risks of whole-body CT include high radiation exposure and iodine contrast agent, but its effectiveness in reducing mortality in low-risk motor vehicle crashes is unclear. Purpose To assess unsuspected injuries revealed at whole-body CT in patients following motor vehicle crash (MVC) meeting only kinetic elements of the Vittel criteria for the severity of trauma, with no evidence of trunk injury and a Glasgow Coma Scale score of 15. Materials and Methods This retrospective study included all consecutive adult patients who consulted an emergency department of a level 1 trauma center between August 2016 and July 2017 if they underwent whole-body CT for one or more kinetic elements of the Vittel criteria, had a normal examination of the trunk, and had a Glasgow Coma Scale score of 15. Data of the MVC mechanism and physical and biologic examinations were collected, as well as patient treatment data after whole-body CT. Whole-body CT examinations were read by two double-blinded readers to help detect unsuspected injuries. Results Ninety-three patients were included; 72 were men with a mean age of 30.8 years ± 12.0 (standard deviation). Sixty-nine patients were occupants of a car. Seventeen patients were hit by a car while on motorbikes, three while on bicycles, and four as pedestrians. Unsuspected injuries were depicted at 11 whole-body CT examinations: eight lung contusions, one acetabular fracture, one sternal fracture, and one adrenal hematoma. None of these injuries required a specific treatment. One patient with lung contusion of more than 30% of lung volume was followed without requiring further treatment. Conclusion In this population, whole-body CT did not lead to any change in patient treatment. These results suggest whole-body CT should not be systematically performed when no evidence of trunk injury is observed in patients following motor vehicle crash meeting only kinetic elements of Vittel criteria. © RSNA, 2019 See also the editorial by Munera and Durso in this issue.

Myocardial constructive work is impaired in hypertrophic cardiomyopathy and predicts left ventricular fibrosis.

BACKGROUND: The estimation of myocardial work by pressure strain loops (PSLs) is a totally new non-invasive approach to assess myocardial performance, and its role in patients with hypertrophic cardiomyopathy is unknown. The aims of the present study are therefore: (a) to compare myocardial work in patients with non-obstructive hypertrophic cardiomyopathy (HCM) and in a subset of age-matched healthy controls and (b) to assess the correlation between myocardial work and left ventricular (LV) fibrosis. DESIGN: Eighty-two patients with non-obstructive HCM (58 ± 14 years) and 20 age-matched healthy subjects (58 ± 7 years, P = 0.99) underwent standard and speckle-tracking echocardiography to assess myocardial dimensions and deformation parameters. PSLs analysis was used to estimate global myocardial constructive work (GCW) and wasted work (GWW). LV fibrosis was estimated at cardiac magnetic resonance (CMR) by qualitative assessment of late gadolinium enhancement (LGE), and significant fibrosis was defined as LGE in ≥2 LV segments. RESULTS: Global constructive work (1599 ± 423 vs 2248 ± 249 mm Hg%, P < 0.0001) was significantly reduced in HCM compared to the control group. No difference was observed in GWW (141 ± 125 vs 101 ± 88 mm Hg%, P = 0.18) and LV ejection fraction (LVEF) (63 ± 13 vs 66 ± 4% P = 0.17) between the two groups. In HCM, GCW was the only predictor of LV fibrosis at multivariable analysis (OR 1.01, 95% CI: 0.99-1.08, P = 0.04). A cutoff value of 1623 mm Hg% (AUC 0.80, 95% CI: 0.66-0.93, P < 0.0001) was able to predict myocardial fibrosis with a good sensitivity and fair specificity (82% and 67%, respectively). CONCLUSIONS: Global constructive work is significantly reduced in HCM despite normal LVEF and is associated with the LV fibrosis as assessed by LGE.

Management of aortic valve replacement according to the gradient across symptomatic aortic valve stenosis and its prognostic impact.

BACKGROUND: Treatment strategy for low-gradient (LG) aortic stenosis (AS) remains an unresolved issue. The presence of a low aortic gradient and preserved left ventricular ejection fraction (LVEF) might lead toward the underestimation of aortic stenosis severity and a more conservative management. We sought (a) to describe the nature and timing of intervention according to flow/gradient subgroups in patibents with LG-AS, (2) to determine the factors associated with the decision to intervene, and (c) to describe prognosis. METHODS AND RESULTS: One hundred and ten patients prospectively included in this study underwent a standardized clinical and imaging evaluation at inclusion and at 1-year follow-up. According to aortic flow, gradient and LVEF, patients were divided into 4 groups: LG-normal flow [n = 27], LG-low flow-low LVEF [n = 27], LG-low flow-normal LVEF [n = 16], and high gradient (HG) [n = 40]). 73% of patients underwent AVR 86 ± 59 days after the initial assessment. The HG subgroup had significantly higher intervention rates (P < .001). In multivariable analysis, four parameters were associated with the AVR: aortic gradient (HR 1.52 [1.10-2.11], P = .012), LVEF (HR 0.58 [0.40-0.85], P = .006), atrial fibrillation (HR 0.43 [0.021-0.87], P = .019), and NT-proBNP (HR 0.92[0.86-0.98), P = .008]. Patients operated earlier had better outcomes than those having a delayed AVR (P = .042). LG-AS patients had worse outcomes than HG-AS patients (P < .001). CONCLUSION: Compared to HG-AS, LG-AS is less likely to benefit from an AVR and had a significantly worse outcome. Further interventional studies are needed to investigate the timing of AVR in these patients.

An improved nonlinear diffusion in Laplacian pyramid domain for cone beam CT denoising during image-guided vascular intervention.

BACKGROUND: Cone-beam computed tomography (CBCT) acquisition during endovascular aneurysm repair is an emergent technology with more and more applications. It may provide 3-D information to achieve guidance of intervention. However, there is growing concern on the overall radiation doses delivered to patients, thus a low dose protocol is called when scanning. But CBCT images with a low dose protocol are degraded, resulting in streak artifacts and decreased contrast-to-noise ratio (CNR). In this paper, a Laplacian pyramid-based nonlinear diffusion is proposed to improve the quality of CBCT images. METHOD: We first transform the CBCT image into its pyramid domain, then a modified nonlinear diffusion is performed in each level to remove noise across edges while keeping edges as far as possible. The improved diffusion coefficient is a function of the gradient magnitude image; the threshold in the modified diffusion function is estimated using the median absolute deviation (MAD) estimator; the time step is automatically determined by iterative image changes and the iteration is stopped according to mean absolute error between two adjacent diffusions. Finally, we reconstruct the Laplacian pyramid using the processed pyramid images in each level. RESULT: Results from simulation show that the filtered image from the proposed method has the highest peak signal-noise ratio (81.92), the highest correlation coefficient (99.77%) and the lowest mean square error (27.61), compared with the other four methods. In addition, it has highest contrast-to-noise ratio and sharpness in ROIs. Results from real CBCT images show that the proposed method shows better smoothness in homogeneous regions meanwhile keeps bony structures clear. CONCLUSION: Simulation and patient studies show that the proposed method has a good tradeoff between noise/artifacts suppression and edge preservation.

Remote Ischemic Preconditioning and Contrast-Induced Nephropathy: A Systematic Review.

BACKGROUND: The use of imaging is increasing in clinical practice either for diagnosis or intervention. In these aims, contrast medium (CM) is widely used. However, CM administration can induce contrast-induced nephropathy (CIN). The incidence of CIN varies from 2% to 50% depending on patient risk factors, and CIN is the third cause of renal insufficiency. To date, methods such as hyperhydration to prevent CIN have a low level of evidence. Remote ischemic preconditioning (RIPC), which has already proved its efficiency in the cardiology field, seems to be a promising technique for CIN prevention. The aim of this work was to carry out a systematic review of the literature of the randomized clinical studies on RIPC in the prevention of CIN in man. METHODS: We conducted a systematic review of randomized clinical studies on the RIPC in the prevention of CIN in man. Documentary sources were PubMed articles published until June 2015. Randomized clinical trials of RIPC in preventing CIN in human were reviewed. RESULTS: Five articles were selected for the analysis. One article studied the impact of RIPC in a population at high risk of CIN, whereas the other 4 analyzed populations at low, moderate or unknown risk of CIN. In 4 studies, except the later one, the risk of CIN was based on the Mehran score that was previously published. In the high-risk population, a decrease in the incidence of CIN was found in the RIPC group compared with the control group (12% against 40%; P = 0.002). Among the 3 other studies using the Mehran's score, one also demonstrated the interest of such a procedure in a subgroup of high-risk patients. A second one found a low incidence of CIN in the RIPC group ([5 of 47; 10%] as compared with a control group [17 of 47; 36%] P = 0.003) in patients at the low risk of CIN. In another low-risk population, a significant lower level of a biological marker (liver-type fatty acid-binding protein) that assesses a renal impairment was found in the RIPC compared with the control group. CONCLUSIONS: Only 5 studies were found in this search, which may constitute a limitation. However, RIPC appears as a promising method to prevent CIN since it is a noninvasive, low cost, easy, and safe method. More randomized controlled trials are needed to confirm these preliminary results.

Breast dose reduction options during thoracic CT: influence of breast thickness.

OBJECTIVE: Little is known about the effectiveness of dose reduction options according to breast thickness. The purpose of this phantom study was to compare the effects on dose and noise of bismuth shielding versus a low kilovoltage for different breast thicknesses. MATERIALS AND METHODS: CT acquisitions were performed first at 120 kVp (reference acquisition), then at 120 kVp with shielding and at 100 kVp without shielding on a phantom with three different prosthetic breast thicknesses, corresponding to the minimum, median, and maximum values first measured in a sample of 30 female thoracic CT examinations, which were randomly selected. Breast doses were measured with optically stimulated luminescence dosimeters placed on and beneath the prosthetic breast. For noise evaluation, the CT number SDs were measured within six ROIs at increasing depths. RESULTS: Taking into account all breast thicknesses, the average breast dose was reduced by 42.1% with shielding and by 33.0% at 100 kVp (p=0.009). In-depth noise increased less with shielding (19.0% vs 32.1%, p<0.0001). For 1-cm breast thickness, the breast dose fell by 46.5% and 29.7% with shielding and 100 kVp, respectively (p=0.01), and in-depth noise increased by 19.5% and 33.9% (p=0.01). The corresponding values for 2-cm breast thickness were -38.5% and -30.1%, (p=0.02) and 16.5% and 33.5% (p=0.001), whereas those for 4-cm thickness were -40.6% and -40.5% (p=0.95) and 20.7 and 29.2% (p=0.02). CONCLUSION: Greater breast dose reduction is achieved by shielding for breast thicknesses less than 4 cm. Regardless of breast thickness, shielding leads to a smaller increase in in-depth noise.