Atrial Fibrosis on MRI in Patients
Introduction
We studied the extent and distribution of left atrial (LA) fibrosis on delayed‐enhanced (DE) MRI in a general cardiology population.
Methods and ...Results
One hundred ninety consecutive patients referred for cardiac MRI underwent DE imaging using a free breathing method. The population comprised 60 AF patients and 130 patients without AF, including 75 with structural heart disease (SHD). DE was quantified using histogram thresholding, expressed in % of the wall. Regression analysis was performed to identify predictors of DE. Additionally, DE was registered on a template to study its distribution in subpopulations. In the total population, age, AF, and SHD were independently associated with DE. DE was increasingly observed from 11.1 ± 4.7% in patients with no SHD nor AF, 18.8 ± 7.8% in SHD and no AF history, 22.9 ± 7.8% in paroxysmal AF, to 27.8 ± 7.7% in persistent AF. Among non‐AF patients, age and SHD were independently associated with DE. Among AF patients, female gender and AF persistence were independently associated with DE. DE was variably distributed but more frequently detected in the posterior wall.
Conclusion
Age, history of AF, and SHD are the most powerful predictors of atrial fibrosis, as detected by MRI, in a general cardiology population. Atrial fibrosis predominates in the posterior LA wall.
Abstract
Aims
To identify the correlates of focal scar and diffuse fibrosis in patients with history of tetralogy of Fallot (TOF) repair.
Methods and results
Consecutive patients with prior TOF ...repair underwent electrocardiogram, 24-h Holter, transthoracic echocardiography, exercise testing, and cardiac magnetic resonance (CMR) including cine imaging to assess ventricular volumes and ejection fraction, T1 mapping to assess left ventricular (LV) and right ventricular (RV) diffuse fibrosis, and free-breathing late gadolinium-enhanced imaging to quantify scar area at high spatial resolution. Structural imaging data were related to clinical characteristics and functional imaging markers. Cine and T1 mapping results were compared with 40 age- and sex-matched controls. One hundred and three patients were enrolled (age 28 ± 15 years, 36% women), including 36 with prior pulmonary valve replacement (PVR). Compared with controls, TOF showed lower LV ejection fraction (LVEF) and RV ejection fraction (RVEF), and higher RV volume, RV wall thickness, and native T1 and extracellular volume values on both ventricles. In TOF, scar area related to LVEF and RVEF, while LV and RV native T1 related to RV dilatation. On multivariable analysis, scar area and LV native T1 were independent correlates of ventricular arrhythmia, while RVEF was not. Patients with history of PVR showed larger scars on RV outflow tract but shorter LV and RV native T1.
Conclusion
Focal scar and biventricular diffuse fibrosis can be characterized on CMR after TOF repair. Scar size relates to systolic dysfunction, and diffuse fibrosis to RV dilatation. Both independently relate to ventricular arrhythmias. The finding of shorter T1 after PVR suggests that diffuse fibrosis may reverse with therapy.
Our aim was to develop practical models built with simple clinical and radiological features to help diagnosing Coronavirus disease 2019 COVID-19 in a real-life emergency cohort. To do so, 513 ...consecutive adult patients suspected of having COVID-19 from 15 emergency departments from 2020-03-13 to 2020-04-14 were included as long as chest CT-scans and real-time polymerase chain reaction (RT-PCR) results were available (244 47.6% with a positive RT-PCR). Immediately after their acquisition, the chest CTs were prospectively interpreted by on-call teleradiologists (OCTRs) and systematically reviewed within one week by another senior teleradiologist. Each OCTR reading was concluded using a 5-point scale: normal, non-infectious, infectious non-COVID-19, indeterminate and highly suspicious of COVID-19. The senior reading reported the lesions' semiology, distribution, extent and differential diagnoses. After pre-filtering clinical and radiological features through univariate Chi-2, Fisher or Student t-tests (as appropriate), multivariate stepwise logistic regression (Step-LR) and classification tree (CART) models to predict a positive RT-PCR were trained on 412 patients, validated on an independent cohort of 101 patients and compared with the OCTR performances (295 and 71 with available clinical data, respectively) through area under the receiver operating characteristics curves (AUC). Regarding models elaborated on radiological variables alone, best performances were reached with the CART model (i.e., AUC = 0.92 versus 0.88 for OCTR, sensitivity = 0.77, specificity = 0.94) while step-LR provided the highest AUC with clinical-radiological variables (AUC = 0.93 versus 0.86 for OCTR, sensitivity = 0.82, specificity = 0.91). Hence, these two simple models, depending on the availability of clinical data, provided high performances to diagnose positive RT-PCR and could be used by any radiologist to support, modulate and communicate their conclusion in case of COVID-19 suspicion. Practically, using clinical and radiological variables (GGO, fever, presence of fibrotic bands, presence of diffuse lesions, predominant peripheral distribution) can accurately predict RT-PCR status.
Mutations in factor H (CFH), factor I (IF), and membrane cofactor protein (MCP) genes have been described as risk factors for atypical hemolytic uremic syndrome (aHUS). This study analyzed the impact ...of complement mutations on the outcome of 46 children with aHUS. A total of 52% of patients had mutations in one or two of known susceptibility factors (22, 13, and 15% of patients with CFH, IF, or MCP mutations, respectively; 2% with CFH+IF mutations). Age <3 mo at onset seems to be characteristic of CFH and IF mutation-associated aHUS. The most severe prognosis was in the CFH mutation group, 60% of whom reached ESRD or died within <1 yr. Only 30% of CFH mutations were localized in SCR20. MCP mutation-associated HUS has a relapsing course, but none of the children reached ESRD at 1 yr. Half of patients with IF mutation had a rapid evolution to ESRD, and half recovered. Plasmatherapy seemed to have a beneficial effect in one third of patients from all groups except for the MCP mutation group. Only eight (33%) of 24 kidney transplantations that were performed in 15 patients were successful. Graft failures were due to early graft thrombosis (50%) or HUS recurrence. In conclusion, outcome of HUS in patients with CFH mutation is catastrophic, and posttransplantation outcome is poor in all groups except for the MCP mutation group. New therapies are urgently needed, and further research should elucidate the unexplained HUS group.
Background
COVID-19 pandemic highlighted the need for real-time monitoring of diseases evolution to rapidly adapt restrictive measures. This prospective multicentric study aimed at investigating ...radiological markers of COVID-19-related emergency activity as global estimators of pandemic evolution in France. We incorporated two sources of data from March to November 2020: an open-source epidemiological dataset, collecting daily hospitalisations, intensive care unit admissions, hospital deaths and discharges, and a teleradiology dataset corresponding to the weekly number of CT-scans performed in 65 emergency centres and interpreted remotely. CT-scans specifically requested for COVID-19 suspicion were monitored. Teleradiological and epidemiological time series were aligned. Their relationships were estimated through a cross-correlation function, and their extremes and breakpoints were compared. Dynamic linear models were trained to forecast the weekly hospitalisations based on teleradiological activity predictors.
Results
A total of 100,018 CT-scans were included over 36 weeks, and 19,133 (19%) performed within the COVID-19 workflow. Concomitantly, 227,677 hospitalisations were reported. Teleradiological and epidemiological time series were almost perfectly superimposed (cross-correlation coefficients at lag 0: 0.90–0.92). Maximal number of COVID-19 CT-scans was reached the week of 2020-03-23 (1 086 CT-scans), 1 week before the highest hospitalisations (23,542 patients). The best valid forecasting model combined the number of COVID-19 CT-scans and the number of hospitalisations during the prior two weeks and provided the lowest mean absolute percentage (5.09%, testing period: 2020-11-02 to 2020-11-29).
Conclusion
Monitoring COVID-19 CT-scan activity in emergencies accurately and instantly predicts hospitalisations and helps adjust medical resources, paving the way for complementary public health indicators.
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 (CT
covid
) and whole chest CT scan activities (CT
chest
) 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 CT
chest
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 CT
covid
on CT
chest
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 CT
covid
(
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 (CT
total
) were performed among the responding centers, including 61,784 (52%) CT performed for COVID-19 (CT
covid
).
• Across the country, the ratio CT
covid
/CT
total
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.
Objectives
To evaluate the accuracy of diagnoses of COVID-19 based on chest CT as well as inter-observer agreement between teleradiologists during on-call duty and senior radiologists in suspected ...COVID-19 patients.
Materials and methods
From March 13, 2020, to April 14, 2020, consecutive suspected COVID-19 adult patients who underwent both an RT-PCR test and chest CT from 15 hospitals were included in this prospective study. Chest CTs were immediately interpreted by the on-call teleradiologist and were systematically blind reviewed by a senior radiologist. Readings were categorised using a five-point scale: (1) normal; (2) non-infectious findings; (3) infectious findings but not consistent with COVID-19 infection; (4) consistent with COVID-19 infection; and (5) typical appearance of COVID-19 infection. The diagnostic accuracy of chest CT and inter-observer agreement using the kappa coefficient were evaluated over the study period.
Results
In total, 513 patients were enrolled, of whom 244/513 (47.6%) tested positive for RT-PCR. First readings were scored 4 or 5 in 225/244 (92%) RT-PCR+ patients, and between 1 and 3 in 201/269 (74.7%) RT-PCR− patients. The data were highly consistent (weighted kappa = 0.87) and correlated with RT-PCR (
p
< 0.001, AUC
1st-reading
= 0.89, AUC
2nd-reading
= 0.93). The negative predictive value for scores of 4 or 5 was 0.91–0.92, and the PPV for a score of 5 was 0.89–0.96 at the first and second readings, respectively. Diagnostic accuracy was consistent over the study period, irrespective of a variable prevalence rate.
Conclusion
Chest CT demonstrated high diagnostic accuracy with strong inter-observer agreement between on-call teleradiologists with varying degrees of experience and senior radiologists over the study period.
Key Points
• The accuracy of readings by on-call teleradiologists, relative to second readings by senior radiologists, demonstrated a sensitivity of 0.75–0.79, specificity of 0.92–0.97, NPV of 0.80–0.83, and PPV of 0.89–0.96, based on “typical appearance,” as predictive of RT-PCR+.
• Inter-observer agreement between the first reading in the emergency setting and the second reading by the senior emergency teleradiologist was excellent (weighted kappa = 0.87).
Several case reports suggest that rituximab (RTX) could be effective in steroid-dependent nephrotic syndrome, but RTX efficacy has not yet been studied in a series of patients. Safety and efficacy of ...RTX were assessed in a multicenter series of 22 patients aged 6.3–22 years with severe steroid-dependent nephrotic syndrome or steroid-resistant but cyclosporin-sensitive idiopathic nephrotic syndrome. Patients were treated with two to four infusions of RTX. Seven patients were nephrotic at the time of RTX treatment. Peripheral B cells were depleted in all subjects. Remission was induced in three of the seven proteinuric patients. One or more immunosuppressive (IS) treatments could be withdrawn in 19 patients (85%), with no relapse of proteinuria and without increasing other IS drugs. RTX was effective in all patients when administered during a proteinuria-free period in association with other IS agents. When relapses occurred, they were always associated with an increase in CD19 cell count. Adverse effects were observed in 45% of cases, but most of them were mild and transient. This study suggests that RTX could be an effective treatment for severe steroid-dependent nephrotic syndrome.
Background
Biological studies suggested that the COVID-19 outbreak in France occurred before the first official diagnosis on January 24, 2020. We investigated this controversial topic using a large ...collection of chest CTs performed throughout French emergency departments within 6 months before the 1st lockdown.
Results
Overall, 49,311 consecutive patients (median age: 60 years, 23,636/49,311 47.9% women) with available chest CT images and reports from 61 emergency departments between September 1, 2020, and March 16, 2020 (day before the 1st French lockdown), were retrospectively included in this multicentre study. In the macroscopic analysis of reports automatically (labelled for presence of ground glass opacities GGOs, reticulations, and bilateral and subpleural abnormalities), we found a significant breakpoint on February 17, 2020, for the weekly time series with 1, 2 and ≥ 3 of these 4 radiological features, with 146/49,311 (0.3%) patients showing bilateral abnormalities and ground glass opacities (GGOs) from that day. According to radiologists, 22/146 (15.1%) CT images showed typical characteristics of COVID-19, including 4/146 (2.7%) before February 2020. According to hospital records, one patient remained without microbial diagnosis, two patients had proven influenza A and one patient had concomitant influenza A and mycoplasma infection.
Conclusion
These results suggest that SARS-CoV-2 was not circulating in the areas covered by the 61 emergency departments involved in our study before the official beginning of the COVID-19 outbreak in France. In emergency patients, the strong resemblance among mycoplasma, influenza A and SARS-CoV-2 lung infections on chest CT and the nonspecificity of CT patterns in low prevalence periods is stressed.
Critical relevance statement
We proposed here an innovative approach to revisit a controversial ‘real’ start of the COVID-19 pandemic in France based on (1) a population-level approach combining text mining, time series analysis and an epidemiological dataset and (2) a patient-level approach with careful retrospective reading of chest CT scans complemented by analysis of samples performed contemporarily to the chest CT. We showed no evidence that SARS-CoV-2 was actively circulating in France before February 2020.
Graphical Abstract
Key points
1. Emergency teleradiology databases enable both population-level and patient-level analyses and facilitate revisiting the beginning of the COVID-19 pandemic.
2. The rates of typical COVID-19 chest CTs did not increase before February 2020.
3. Typical COVID-19 chest CTs before February 2020 were diagnosed as influenza A and mycoplasma pneumonia.
Nephronophthisis is an autosomal recessive chronic tubulointerstitial disease that progresses to end-stage renal disease (ESRD) in about 10% of cases during infancy. Mutations in the INVS (NPHP2) ...gene were found in a few patients with infantile nephronophthisis. Mutations of NPHP3, known to be associated with adolescent nephronophthisis, were found in two patients with early-onset ESRD. Here we screened 43 families with infantile nephronophthisis (ESRD less than 5 years of age) for NPHP2 and NPHP3 mutations and determined genotype–phenotype correlations. In this cohort there were 16 families with NPHP2 mutations and NPHP3 mutations in seven. Three patients carried only one heterozygous mutation in NPHP3. ESRD arose during the first 2 years of life in 16 of 18 patients with mutations in NPHP2, but in only two patients with mutations in NPHP3. Renal morphology, characterized by hyper-echogenic kidneys on ultrasound and tubular lesions with interstitial fibrosis on histology, was similar in the two patient groups. The kidney sizes were highly diverse and ultrasound-visualized cysts were present in a minority of cases. Extra-renal anomalies were found in 80% of the entire cohort including hepatic involvement (50%), cardiac valve or septal defects (20%) and recurrent bronchial infections (18%). We show that NPHP3 mutations in both infantile and adolescent nephronophthisis point to a common pathophysiological mechanism despite their different clinical presentations.
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