Positron Emission Tomography with [18 F]-DPA-714 Unveils a Smoldering Component in Most Multiple Sclerosis Lesions which Drives Disease Progression.

OBJECTIVE: To determine the prognostic value of persisting neuroinflammation in multiple sclerosis (MS) lesions, we developed a 18 kDa-translocator-protein-positron emission tomography (PET) -based classification of each lesion according to innate immune cell content and localization. We assessed the respective predictive value of lesion phenotype and diffuse inflammation on atrophy and disability progression over 2 years. METHODS: Thirty-six people with MS (disease duration 9 ± 6 years; 12 with relapsing-remitting, 13 with secondary-progressive, and 11 with primary-progressive) and 19 healthy controls (HCs) underwent a dynamic [18 F]-DPA-714-PET. At baseline and after 2 years, the patients also underwent a magnetic resonance imaging (MRI) and neurological examination. Based on a threshold of significant inflammation defined by a comparison of [18 F]-DPA-714 binding between patients with MS and HCs, white matter lesions were classified as homogeneously active (active center), rim-active (inactive center and active periphery), or nonactive. Longitudinal cortical atrophy was measured using Jacobian integration. RESULTS: Patients with MS had higher innate inflammation in normal-appearing white matter (NAWM) and cortex than HCs (respective standardized effect size = 1.15, 0.89, p = 0.003 and < 0.001). Out of 1,335 non-gadolinium-enhancing lesions, 53% were classified as homogeneously-active (median = 17 per patient with MS), 6% rim-active (median = 1 per patient with MS), and 41% non-active (median = 14 per patient with MS). The number of homogenously-active lesions was the strongest predictor of longitudinal changes, associating with cortical atrophy (ß = 0.49, p = 0.023) and Expanded Disability Status Scale (EDSS) changes (ß = 0.35, p = 0.023) over 2 years. NAWM and cortical binding were not associated to volumetric and clinical changes. INTERPRETATION: The [18 F]-DPA-714-PET revealed that an unexpectedly high proportion of MS lesions have a smoldering component, which predicts atrophy and clinical progression. This suggests that following the acute phase, most lesions develop a chronic inflammatory component, promoting neurodegeneration and clinical progression. ANN NEUROL 2023;94:366-383.

Incidence, Clinical Characteristics, and Impact of Absent Echocardiographic Signs in Patients With Infective Endocarditis After Transcatheter Aortic Valve Implantation.

BACKGROUND: Echocardiography is the primary imaging modality for diagnosis of infective endocarditis (IE) in prosthetic valve endocarditis (PVE) including IE after transcatheter aortic valve implantation (TAVI). This study aimed to evaluate the characteristics and clinical outcomes of patients with absent compared with evident echocardiographic signs of TAVI-IE. METHODS: Patients with definite TAVI-IE derived from the Infectious Endocarditis after TAVI International Registry were investigated comparing those with absent and evident echocardiographic signs of IE defined as vegetation, abscess, pseudo-aneurysm, intracardiac fistula, or valvular perforation or aneurysm. RESULTS: Among 578 patients, 87 (15.1%) and 491 (84.9%) had absent (IE-neg) and evident (IE-pos) echocardiographic signs of IE, respectively. IE-neg were more often treated via a transfemoral access with a self-expanding device and had higher rates of peri-interventional complications (eg, stroke, major vascular complications) during the TAVI procedure (P < .05 for all). IE-neg had higher rates of IE caused by Staphylococcus aureus (33.7% vs 23.2%; P = .038) and enterococci (37.2% vs 23.8%; P = .009) but lower rates of coagulase-negative staphylococci (4.7% vs 20.0%, P = .001). IE-neg was associated with the same dismal prognosis for in-hospital mortality in a multivariate binary regression analysis (odds ratio: 1.51; 95% confidence interval [CI]: .55-4.12) as well as a for 1-year mortality in Cox regression analysis (hazard ratio: 1.10; 95% CI: .67-1.80). CONCLUSIONS: Even with negative echocardiographic imaging, patients who have undergone TAVI and presenting with positive blood cultures and symptoms of infection are a high-risk patient group having a reasonable suspicion of IE and the need for an early treatment initiation.

Tau-PET imaging predicts cognitive decline and brain atrophy progression in early Alzheimer's disease.

OBJECTIVES: To explore whether regional tau binding measured at baseline is associated with the rapidity of Alzheimer's disease (AD) progression over 2 years, as assessed by the decline in specified cognitive domains, and the progression of regional brain atrophy, in comparison with amyloid-positron emission tomography (PET), MRI and cerebrospinal fluid (CSF) biomarkers. METHODS: Thirty-six patients with AD (positive CSF biomarkers and amyloid-PET) and 15 controls underwent a complete neuropsychological assessment, 3T brain MRI, [11C]-PiB and [18F]-flortaucipir PET imaging, and were monitored annually over 2 years, with a second brain MRI after 2 years. We used mixed effects models to explore the relations between tau-PET, amyloid-PET, CSF biomarkers and MRI at baseline and cognitive decline and the progression of brain atrophy over 2 years in patients with AD. RESULTS: Baseline tau-PET was strongly associated with the subsequent cognitive decline in regions that are usually associated with each cognitive domain. No significant relationship was observed between the cognitive decline and initial amyloid load, regional cortical atrophy or CSF biomarkers. Baseline tau tracer binding in the superior temporal gyrus was associated with subsequent atrophy in an inferomedial temporal volume of interest, as was the voxelwise tau tracer binding with subsequent cortical atrophy in the superior temporal, parietal and frontal association cortices. CONCLUSIONS: These results suggest that tau tracer binding is predictive of cognitive decline in AD in domain-specific brain areas, which provides important insights into the interaction between tau burden and neurodegeneration, and is of the utmost importance to develop new prognostic markers that will help improve the design of therapeutic trials.

Spontaneous remyelination in lesions protects the integrity of surrounding tissues over time in multiple sclerosis.

BACKGROUND AND PURPOSE: Lesion remyelination preserves axonal integrity in animal models of multiple sclerosis (MS), but an in vivo demonstration of its protective effect on surrounding tissues in humans is lacking. METHODS: Nineteen persons with MS were enrolled in a cohort study and underwent two positron emission tomography (PET)/magnetic resonance imaging (MRI) scans 1-4 months apart. Voxelwise maps of Pittsburgh compound B distribution volume ratio, reflecting myelin content, were used to calculate an index of baseline demyelination, and of dynamic demyelination and remyelination over the follow-up in 549 single white matter lesions. Changes in fractional anisotropy and mean diffusivity, reflecting microstructural damage, were calculated in the proximal and distal 3-mm-thick rings surrounding each lesion, and used to classify perilesional microstructure as "preserved" or "worsening" over the follow-up. Mixed-effect linear models and logistic regressions were employed to investigate whether PET-derived lesional indices were associated with changes in MRI metrics in perilesions, and to identify which of them best predicted the microstructural evolution of perilesions over time. RESULTS: A higher index of remyelination, and a lower index of baseline and dynamic demyelination in lesions were associated with a less severe microstructural deterioration of the corresponding proximal and distal perilesions over time (p-value range: <0.001-0.012), but the index of remyelination was the best predicting variable of perilesional fate. For every extra 1% of remyelination within each lesion, the probability of the corresponding perilesional microstructure remaining preserved over time increased by 39% (odds ratio = 6.62, 95% confidence interval = 2.16-20.32, p < 0.001). CONCLUSIONS: Intralesional remyelination is associated with the microstructural preservation of surrounding tissues, possibly preventing neuroaxonal damage resulting from Wallerian degeneration.

Choroid Plexus Enlargement in Inflammatory Multiple Sclerosis: 3.0-T MRI and Translocator Protein PET Evaluation.

Background Choroid plexuses (CPs) have been suggested as a key gateway for inflammation in experimental autoimmune encephalitis, but in vivo evidence of their involvement in multiple sclerosis (MS) is lacking. Purpose To assess CP volumetric and inflammatory changes in patients with MS versus healthy control participants. Materials and Methods This was a secondary analysis of 97 patients (61 with relapsing-remitting MS [RRMS] and 36 with progressive MS) and 44 healthy control participants who participated in three prospective 3.0-T brain MRI studies between May 2009 and September 2017. A subgroup of 37 patients and 19 healthy control participants also underwent translocator protein fluorine 18 (18F)-DPA-714 PET for neuroinflammation. Relapses and disability scores were collected at baseline and over 2 years. CPs were manually segmented on three-dimensional T1-weighted images; other brain volumes were additionally segmented. Volumes were expressed as a ratio of intracranial volume. The 18F-DPA-714 distribution volume ratio was quantified in parenchymal regions, whereas standardized uptake value was used for CP inflammation. Multivariable linear regression analyses were performed to assess CP volumetric and inflammatory differences between patients with MS and healthy control participants and correlations between CP volume and lesion load, brain volumes, 18F-DPA-714 uptake, and annualized relapse rate. Results Ninety-seven patients with MS (mean age, 42 years ± 12 [standard deviation]; 49 women) and 44 healthy control participants (mean age, 39 years ± 14; 23 women) underwent MRI. Thirty-seven patients with MS and 19 healthy control participants underwent PET. CPs were 35% larger in patients with MS (mean value, 15.9 × 10-4 ± 4.5) than in healthy control participants (mean value, 11.8 × 10-4 ± 3.8; P = .004). Subgroup analysis confirmed greater CP volume in patients with RRMS (mean value, 15.5 × 10-4 ± 4.6; P = .008) than in healthy control participants. CP enlargement was greater in patients with active lesions at MRI (mean volume, 18.2 × 10-4 ± 4.9 in patients with lesions that enhanced with gadolinium vs 14.9 × 10-4 ± 4 in patients with lesions that did not enhance with gadolinium; P < .001) and correlated with white matter lesion load (r = 0.39; 95% CI: 0.20, 0.55; P < .001) and 18F-DPA-714 binding in the thalami (r = 0.44; 95% CI: 0.22, 0.72; P = .04) and normal-appearing white matter (r = 0.5; 95% CI: 0.20, 0.71; P = .005). Moreover, it correlated with annualized relapse rate in patients with RRMS (r = 0.37; 95% CI: 0.1, 0.55; P = .005). Finally, patients with MS showed 18.5% higher CP 18F-DPA-714 uptake than control participants (mean value, 0.778 ± 0.23 vs 0.635 ± 0.15, respectively; P = .01). CP volume in patients with RRMS (r = 0.57; 95% CI: 0.37, 0.73; P = .009) correlated with higher 18F-DPA-714 uptake. Conclusion Choroid plexuses (CPs) are enlarged and inflamed in patients with multiple sclerosis (MS), particularly in those with relapsing-remitting MS with inflammatory profiles; CP volumetric analysis could represent an MS imaging marker. © RSNA, 2021 EudraCT no. 2008-004174-40; clinical trial registration nos. NCT02305264 and NCT01651520 Online supplemental material is available for this article.

Comparison of saliva with oral and nasopharyngeal swabs for SARS-CoV-2 detection on various commercial and laboratory-developed assays.

The accurate laboratory detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a crucial element in the fight against coronavirus disease 2019 (COVID-19). Reverse transcription-polymerase chain reaction testing on combined oral and nasopharyngeal swab (ONPS) suffers from several limitations, including the need for qualified personnel, the discomfort caused by invasive nasopharyngeal sample collection, and the possibility of swab and transport media shortage. Testing on saliva would represent an advancement. The aim of this study was to compare the concordance between saliva samples and ONPS for the detection of SARS-CoV-2 on various commercial and laboratory-developed tests (LDT). Individuals were recruited from eight institutions in Quebec, Canada, if they had SARS-CoV-2 RNA detected on a recently collected ONPS, and accepted to provide another ONPS, paired with saliva. Assays available in the different laboratories (Abbott RealTime SARS-CoV-2, Cobas® SARS-CoV-2, Simplexa™ COVID-19 Direct, Allplex™ 2019-nCoV, RIDA®GENE SARS-CoV-2, and an LDT preceded by three different extraction methods) were used to determine the concordance between saliva and ONPS results. Overall, 320 tests were run from a total of 125 saliva and ONPS sample pairs. All assays yielded similar sensitivity when saliva was compared to ONPS, with the exception of one LDT (67% vs. 93%). The mean difference in cycle threshold (∆C t ) was generally (but not significantly) in favor of the ONPS for all nucleic acid amplification tests. The maximum mean ∆​​​​​C t was 2.0, while individual ∆C t varied importantly from -17.5 to 12.4. Saliva seems to be associated with sensitivity similar to ONPS for the detection of SARS-CoV-2 by various assays.

Predictors of Clostridioides difficile Infection Among Asymptomatic, Colonized Patients: A Retrospective Cohort Study.

BACKGROUND: Asymptomatic patients colonized with Clostridioides difficile are at risk of developing C. difficile infection (CDI), but the factors associated with disease onset are poorly understood. Our aims were to identify predictors of hospital-onset CDI (HO-CDI) among colonized patients and to explore the potential benefits of primary prophylaxis to prevent CDI. METHODS: We conducted a retrospective cohort study in a tertiary academic institution. Colonized patients were identified by detecting the tcdB gene by polymerase chain reaction on a rectal swab. Univariate and multivariate logistic regression analyses were used to identify predictors of HO-CDI. RESULTS: There were 19 112 patients screened, from which 960 (5%) colonized patients were identified: 513 met the inclusion criteria. Overall, 39 (7.6%) developed a HO-CDI, with a 30-day attributable mortality of 15%. An increasing length of stay (adjusted odds ratio [aOR] per day, 1.03; P = .006), exposure to multiple classes of antibiotics (aOR per class, 1.45; P = .02), use of opioids (aOR, 2.78; P = .007), and cirrhosis (aOR 5.49; P = .008) were independently associated with increased risks of HO-CDI, whereas the use of laxatives was associated with a lower risk of CDI (aOR 0.36; P = .01). Among the antimicrobials, B-lactam with B-lactamase inhibitors (OR 3.65; P < .001), first-generation cephalosporins (OR 2.38; P = .03), and carbapenems (OR 2.44; P = .03) correlated with the greatest risk of HO-CDI. By contrast, patient age, the use of proton pump inhibitors, and the use of primary prophylaxis were not significant predictors of HO-CDI. CONCLUSIONS: This study identifies several factors that are associated with CDI among colonized patients. Whether modifying these variables could decrease the risk of CDI should be investigated.

Impact of Isolating Clostridium difficile Carriers on the Burden of Isolation Precautions: A Time Series Analysis.

Background: The isolation of asymptomatic Clostridium difficile (CD) carriers may decrease the incidence of hospital-associated C. difficile infections (CDI), but its impact on isolation precaution needs is unknown. Methods: A time series analysis was conducted to investigate the impact of isolating CD carriers on the burden of isolation precautions from 2008 to 2016 in a Canadian hospital. To account for the changes in C. difficile infection control policies, the series was divided into 3 intervention periods: period 1 (2008-2011), isolation of patients with CDI until symptom resolution; period 2 (2011-2013), isolation of patients with CDI until discharge; and period 3 (2013-2016), isolation of patients with CDI and CD carriers until discharge. We compared the prevalence of isolation-days for C. difficile (ie, for either CDI or carriage) per 1000 patient-days between study periods. Changes in trend were analyzed by segmented regression analysis. Results: A total of 806357 patient-days and 20455 isolation-days were included. Isolation-day prevalence during periods 1, 2, and 3 were 12.9, 26.2, and 37.8 isolation-days per 1000 patient-days, respectively (P < .001 between periods). Isolating CD carriers was associated with an increase in isolation-days' prevalence compared with period 2 (rate ratio [RR], 1.66; P < .001) followed by a significant decrease in trend (RR per 4-week period, 0.97; P < .001). The downward trend was mainly due to decreasing isolation needs for patients with CDI (RR per 4-week period, 0.94; P < .001) rather than for carriage (RR per 4-week period, 0.996; P = .21). Conclusions: Isolating CD carriers led to an initial increase in isolation needs that was partially compensated by a decrease in isolation needs for CDI.

Detection and Isolation of Clostridium difficile Asymptomatic Carriers During Clostridium difficile Infection Outbreaks: An Exploratory Study.

During 4 Clostridium difficile infection outbreaks, unit-wide screening of 114 patients led to detection and isolation of 15 (13%) C. difficile asymptomatic carriers. Carriage prevalence varied between outbreaks, from 0% to 29% (P = .004). Isolating carriers was not associated with significantly shorter outbreak durations, compared with historical controls.

Early and protective microglial activation in Alzheimer's disease: a prospective study using 18F-DPA-714 PET imaging.

While emerging evidence suggests that neuroinflammation plays a crucial role in Alzheimer's disease, the impact of the microglia response in Alzheimer's disease remains a matter of debate. We aimed to study microglial activation in early Alzheimer's disease and its impact on clinical progression using a second-generation 18-kDa translocator protein positron emission tomography radiotracer together with amyloid imaging using Pittsburgh compound B positron emission tomography. We enrolled 96 subjects, 64 patients with Alzheimer's disease and 32 controls, from the IMABio3 study, who had both (11)C-Pittsburgh compound B and (18)F-DPA-714 positron emission tomography imaging. Patients with Alzheimer's disease were classified as prodromal Alzheimer's disease (n = 38) and Alzheimer's disease dementia (n = 26). Translocator protein-binding was measured using a simple ratio method with cerebellar grey matter as reference tissue, taking into account regional atrophy. Images were analysed at the regional (volume of interest) and at the voxel level. Translocator protein genotyping allowed the classification of all subjects in high, mixed and low affinity binders. Thirty high+mixed affinity binders patients with Alzheimer's disease were dichotomized into slow decliners (n = 10) or fast decliners (n = 20) after 2 years of follow-up. All patients with Alzheimer's disease had an amyloid positive Pittsburgh compound B positron emission tomography. Among controls, eight had positive amyloid scans (n = 6 high+mixed affinity binders), defined as amyloidosis controls, and were analysed separately. By both volumes of interest and voxel-wise comparison, 18-kDa translocator protein-binding was higher in high affinity binders, mixed affinity binders and high+mixed affinity binders Alzheimer's disease groups compared to controls, especially at the prodromal stage, involving the temporo-parietal cortex. Translocator protein-binding was positively correlated with Mini-Mental State Examination scores and grey matter volume, as well as with Pittsburgh compound B binding. Amyloidosis controls displayed higher translocator protein-binding than controls, especially in the frontal cortex. We found higher translocator protein-binding in slow decliners than fast decliners, with no difference in Pittsburgh compound B binding. Microglial activation appears at the prodromal and possibly at the preclinical stage of Alzheimer's disease, and seems to play a protective role in the clinical progression of the disease at these early stages. The extent of microglial activation appears to differ between patients, and could explain the overlap in translocator protein binding values between patients with Alzheimer's disease and amyloidosis controls.

Diagnostic value of combining ¹¹C-choline and ¹8F-FDG PET/CT in hepatocellular carcinoma.

PURPOSE: In this prospective study, our goal was to emphasize the diagnostic value of combining (11)C-choline and (18)F-FDG PET/CT for hepatocellular carcinoma (HCC) in patients with chronic liver disease. METHODS: Thirty-three consecutive patients were enrolled. All patients were suspected to have HCC based on CT and/or MRI imaging. A final diagnosis was obtained by histopathological examination or by imaging alone according to American Association for the Study of Liver Disease criteria. All patients underwent PET/CT with both tracers within a median of 5 days. All lesions showing higher tracer uptake than normal liver were considered positive for HCC. We examined how tracer uptake was related to biological (serum α-fetoprotein levels) and pathological (differentiation status, peritumoral capsule and vascular invasion) prognostic markers of HCC, as well as clinical observations at 6 months (recurrence and death). RESULTS: Twenty-eight HCC, four cholangiocarcinomas and one adenoma were diagnosed. In the HCC patients, the sensitivity of (11)C-choline, (18)F-FDG and combined (11)C-choline and (18)F-FDG PET/CT for the detection of HCC was 75 %, 36 % and 93 %, respectively. Serum α-fetoprotein levels >200 ng/ml were more frequent among patients with (18)F-FDG-positive lesions than those with (18)F-FDG-negative lesions (p < 0.05). Early recurrence (n=2) or early death (n=5) occurred more frequently in patients with (18)F-FDG-positive lesions than in those with (18)F-FDG-negative lesions (p < 0.05). CONCLUSION: The combined use of (11)C-choline and (18)F-FDG PET/CT detected HCC with high sensitivity. This approach appears to be of potential prognostic value and may facilitate the selection of patients for surgical resection or liver transplantation.

Determinants of brain metabolism changes in mesial temporal lobe epilepsy.

OBJECTIVE: To determine the main factors influencing metabolic changes in mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS). METHODS: We prospectively studied 114 patients with MTLE (62 female; 60 left HS; 15- to 56-year-olds) with (18) F-fluorodeoxyglucose-positron emission tomography and correlated the results with the side of HS, structural atrophy, electroclinical features, gender, age at onset, epilepsy duration, and seizure frequency. Imaging processing was performed using statistical parametric mapping. RESULTS: Ipsilateral hypometabolism involved temporal (mesial structures, pole, and lateral cortex) and extratemporal areas including the insula, frontal lobe, perisylvian regions, and thalamus, more extensively in right HS (RHS). A relative increase of metabolism (hypermetabolism) was found in the nonepileptic temporal lobe and in posterior areas bilaterally. Voxel-based morphometry detected unilateral hippocampus atrophy and gray matter concentration decrease in both frontal lobes, more extensively in left HS (LHS). Regardless of the structural alterations, the topography of hypometabolism correlated strongly with the extent of epileptic networks (mesial, anterior-mesiolateral, widespread mesiolateral, and bitemporal according to the ictal spread), which were larger in RHS. Notably, widespread perisylvian and bitemporal hypometabolism was found only in RHS. Mirror hypermetabolism was grossly proportional to the hypometabolic areas, coinciding partly with the default mode network. Gender-related effect was significant mainly in the contralateral frontal lobe, in which metabolism was higher in female patients. Epilepsy duration correlated with the contralateral temporal metabolism, positively in LHS and negatively in RHS. Opposite results were found with age at onset. High seizure frequency correlated negatively with the contralateral metabolism in LHS. SIGNIFICANCE: Epileptic networks, as assessed by electroclinical correlations, appear to be the main determinant of hypometabolism in MTLE. Compensatory mechanisms reflected by a relative hypermetabolism in the nonepileptic temporal lobe and in extratemporal areas seem more efficient in LHS and in female patients, whereas long duration, late onset of epilepsy, and high seizure frequency may reduce these adaptive changes.

Epidemiology, Risk Factors, and Prophylaxis Use for Pneumocystis jirovecii Pneumonia in the Non-HIV Population: A Retrospective Study in Québec, Canada.

Background: Pneumocystis jirovecii pneumonia (PJP) remains a significant threat in immunocompromised cases. Recent data on epidemiology and risk factors for PJP in non-HIV cases are scarce, and guidelines on appropriate prophylaxis are lacking. Methods: In this multicenter retrospective trial, all non-HIV adult cases admitted to hospitals in Québec City, Canada, between January 2011 and January 2021 with a diagnosis of PJP were assessed for eligibility. Results: An overall 129 cases of PJP were included. More than two-thirds had an underlying hematologic disease or an autoimmune/inflammatory condition. Prior to diagnosis, 83.7% were taking corticosteroids, 71.3% immunosuppressive agents (alone or in combination with corticosteroids), and 62% both. A diagnosis of PJP was noted in 22 patients receiving corticosteroids for treatment <28 days. Two patients developed PJP while undergoing corticosteroid monotherapy at a mean daily prednisone-equivalent dose <20 mg/d; 4.7% of our cohort received a PJP prophylaxis. Current recommendations or accepted clinical practices for PJP prophylaxis would not have applied to 48.8% of our patients. Conclusions: The use of corticosteroids-in monotherapy or in coadministration with other immunosuppressive agents-remains the principal risk factor for PJP in the non-HIV population. Current prophylaxis guidelines and accepted practices are insufficient to adequately prevent PJP and need to be broadened and updated.

Combined in vivo MRI assessment of locus coeruleus and nucleus basalis of Meynert integrity in amnestic Alzheimer's disease, suspected-LATE and frontotemporal dementia.

BACKGROUND: The locus coeruleus (LC) and the nucleus basalis of Meynert (NBM) are altered in early stages of Alzheimer's disease (AD). Little is known about LC and NBM alteration in limbic-predominant age-related TDP-43 encephalopathy (LATE) and frontotemporal dementia (FTD). The aim of the present study is to investigate in vivo LC and NBM integrity in patients with suspected-LATE, early-amnestic AD and FTD in comparison with controls. METHODS: Seventy-two participants (23 early amnestic-AD patients, 17 suspected-LATE, 17 FTD patients, defined by a clinical-biological diagnosis reinforced by amyloid and tau PET imaging, and 15 controls) underwent neuropsychological assessment and 3T brain MRI. We analyzed the locus coeruleus signal intensity (LC-I) and the NBM volume as well as their relation with cognition and with medial temporal/cortical atrophy. RESULTS: We found significantly lower LC-I and NBM volume in amnestic-AD and suspected-LATE in comparison with controls. In FTD, we also observed lower NBM volume but a slightly less marked alteration of the LC-I, independently of the temporal or frontal phenotype. NBM volume was correlated with the global cognitive efficiency in AD patients. Strong correlations were found between NBM volume and that of medial temporal structures, particularly the amygdala in both AD and FTD patients. CONCLUSIONS: The alteration of LC and NBM in amnestic-AD, presumed-LATE and FTD suggests a common vulnerability of these structures to different proteinopathies. Targeting the noradrenergic and cholinergic systems could be effective therapeutic strategies in LATE and FTD.

Correlation between Clostridium difficile bacterial load, commercial real-time PCR cycle thresholds, and results of diagnostic tests based on enzyme immunoassay and cell culture cytotoxicity assay.

The impact of Clostridium difficile fecal loads on diagnostic test results is poorly understood, but it may have clinical importance. In this study, we investigated the relationship between C. difficile fecal load and the results of four assays: a glutamate dehydrogenase (GDH) enzyme immunoassay (EIA), a toxin A/B antigen EIA (ToxAB), a cell culture cytotoxicity assay (CCA), and PCR targeting the tcdB gene. We also compared the PCR cycle threshold (CT) with the results of quantitative culture using Spearman's rank correlation coefficient. Finally, we sequenced the genomes of 24 strains with different detection profiles. A total of 203 clinical samples harboring toxigenic C. difficile were analyzed and sorted into one of four groups: 17 PCR(+) (group 1), 37 PCR(+) GDH(+) (group 2), 24 PCR(+) GDH(+) CCA(+) (group 3), and 125 PCR(+) GDH(+) ToxAB(+) (group 4). The overall median fecal load in log10 CFU/g was 6.67 (interquartile range [IQR], 5.57 to 7.54). The median fecal bacterial load of groups 1, 2, 3, and 4 were 4.15 (IQR, 3.00 to 4.98), 5.74 (IQR, 4.75 to 6.16), 6.20 (IQR, 5.23 to 6.80), and 7.08 (IQR, 6.35 to 7.83), respectively. Group 1 samples had lower fecal loads than those from each of the other groups (P < 0.001). Group 2 samples had lower fecal loads than those from groups 3 and 4 (P < 0.001). There was a significant correlation between PCR CT and fecal loads (ρ = -0.697; P < 0.001). NAP1 strains were associated with the detection of toxins by EIA or CCA (P = 0.041). This study demonstrates an association between C. difficile fecal load and the results of routinely used diagnostic tests.

A 37-Year-Old Man With Right Lung Consolidation.

CASE PRESENTATION: A 37-year-old man attended a medical clinic at the confluence of the Appalachian and the St. Lawrence Valley after 2 weeks of coughing greenish sputum and progressive dyspnea on exertion. In addition, he reported fatigue, fevers, and chills. He had quit smoking a year earlier and was not a drug user. He recently had spent most of his free time outdoors, mountain biking, but had not travelled outside of Canada. Medical history was unremarkable. He did not take any medication. Upper airway samples taken for SARS-CoV-2 proved negative; he was prescribed cefprozil and doxycycline for presumed community-acquired pneumonia. He returned to the emergency room 1 week later with mild hypoxemia, persisting fever, and a chest radiography consistent with lobar pneumonia. The patient was admitted to his local community hospital, and broad-spectrum antibiotics were added to the regimen. Unfortunately, his condition deteriorated over the following week, and he experienced hypoxic respiratory failure for which he required mechanical ventilation before his transfer to our medical center.

Could tau-PET imaging contribute to a better understanding of the different patterns of clinical progression in Alzheimer's disease? A 2-year longitudinal study.

BACKGROUND: Monitoring the progression of Tau pathology makes it possible to study the clinical diversity of Alzheimer's disease. In this 2-year longitudinal PET study, we aimed to determine the progression of [18F]-flortaucipir binding and of cortical atrophy, and their relationships with cognitive decline. METHODS: Twenty-seven AD patients at the mild cognitive impairment/mild dementia stages and twelve amyloid-negative controls underwent a neuropsychological assessment, 3 T brain MRI, and [18F]-flortaucipir PET imaging (Tau1) and were monitored annually over 2 years with a second brain MRI and tau-PET imaging after 2 years (Tau2). We analyzed the progression of tau standardized uptake value ratio (SUVr) and grey matter atrophy both at the regional and voxelwise levels. We used mixed effects models to explore the relations between the progression of SUVr values, cortical atrophy, and cognitive decline. RESULTS: We found an average longitudinal increase in tau SUVr values, except for the lateral temporoparietal cortex where the average SUVr values decreased. Individual analyses revealed distinct profiles of SUVr progression according to temporoparietal Tau1 uptake: high-Tau1 patients demonstrated an increase in SUVr values over time in the frontal lobe, but a decrease in the temporoparietal cortex and a rapid clinical decline, while low-Tau1 patients displayed an increase in SUVr values in all cortical regions and a slower clinical decline. Cognitive decline was strongly associated with the progression of regional cortical atrophy, but only weakly associated with SUVr progression. CONCLUSIONS: Despite a relatively small sample size, our results suggest that tau-PET imaging could identify patients with a potentially "more aggressive" clinical course characterized by high temporoparietal Tau1 SUVr values and a rapid clinical progression. In these patients, the paradoxical decrease in temporoparietal SUVr values over time could be due to the rapid transition to ghost tangles, for which the affinity of the radiotracer is lower. They could particularly benefit from future therapeutic trials, the neuroimaging outcome measures of which deserve to be discussed.

Alveolar echinococcosis in solid organ transplant recipients: a case series from two national cohorts.

Alveolar echinococcosis (AE) is a severe parasitic infection caused by the ingestion of Echinococcus multilocularis eggs. While higher incidence and faster evolution have been reported in immunosuppressed patients, no studies have been performed specifically on AE in transplant patients. We searched for all de novo AE cases diagnosed between January 2008 and August 2018 in solid organ transplant (SOT) recipients included in the Swiss Transplant Cohort Study and the FrancEchino Registry. Eight cases were identified (kidney = 5, lung = 2, heart = 1, liver = 0), half of which were asymptomatic at diagnosis. AE diagnosis was difficult due to the low sensitivity (60%) of the standard screening serology (Em2+) and the frequently atypical radiological presentations. Conversely, Echinococcus Western blot retained good diagnostic performances and was positive in all eight cases. Five patients underwent surgery, but complete resection could only be achieved in one case. Moreover, two patients died of peri-operative complications. Albendazole was initiated in seven patients and was well tolerated. Overall, AE regressed in one, stabilized in three, and progressed in one case, and had an overall mortality of 37.5% (3/8 patients). Our data suggest that AE has a higher mortality and a faster clinical course in SOT recipients; they also suggest that the parasitic disease might be due to the reactivation of latent microscopic liver lesions through immune suppression. Western blot serology should be preferred in this population. Finally, surgery should be considered with caution, because of its low success rate and high mortality, and conservative treatment with albendazole is well tolerated.

Title: Échinococcose alvéolaire chez les receveurs d'une greffe d'organe solide : une série de cas de deux cohortes nationales. Abstract: L'échinococcose alvéolaire (EA) est une maladie parasitaire grave causée par l'ingestion d'œufs d'Echinococcus multilocularis. Bien qu'une plus haute incidence et une évolution plus rapide aient été rapportées chez les patients immunodéprimés, aucune étude n'a été conduite spécifiquement sur cette maladie chez les patients transplantés. Nous avons donc listé tous les cas d'échinococcose alvéolaire apparus de novo entre janvier 2008 et août 2018 chez les patients transplantés d'organe solide inclus dans la cohorte Swiss Transplant Cohort Study et le registre FrancEchino. Huit patients ont été identifiés (rein = 5, poumon = 2, cœur = 1, foie = 0), dont la moitié était asymptomatique au moment du diagnostic. Le diagnostic était compliqué par la basse sensibilité (60 %) de la sérologie standard de dépistage (Em2+) et par les présentations radiologiques atypiques des lésions. Les performances diagnostiques du Western Blot n'étaient toutefois pas affectées et ce test était positif chez tous les patients. Sur les cinq patients opérés, une résection complète n'a été possible que dans un cas, tandis que deux patients sont décédés dans les suites de l'opération. L'albendazole a été introduit chez 7 patients et a été bien toléré. Dans l'ensemble, l'EA s'est stabilisée dans 3 cas, a régressé dans un cas et a progressé dans un autre cas, avec une mortalité de 37,5 % (3/8 patients). Nos résultats suggèrent une mortalité plus élevée et une évolution plus rapide de l'EA chez les patients transplantés. Ils suggèrent aussi que la maladie parasitaire pourrait être due à la réactivation de lésions hépatiques microscopiques latentes à la faveur de l'immunosuppression. Le Western Blot devrait être préféré dans cette population. Finalement, la chirurgie devrait être envisagée avec prudence, étant donnés son faible taux de réussite, le nombre élevé de décès peri-opératoires et la bonne tolérance au traitement conservateur par albendazole.

Association of the Timing and Extent of Cardiac Implantable Electronic Device Infections With Mortality.

Importance: Cardiac implantable electronic device (CIED) infection is a potentially devastating complication with an estimated 12-month mortality of 15% to 30%. The association of the extent (localized or systemic) and timing of infection with all-cause mortality has not been established. Objective: To evaluate the association of the extent and timing of CIED infection with all-cause mortality. Design, Setting, and Participants: This prospective observational cohort study was conducted between December 1, 2012, and September 30, 2016, in 28 centers across Canada and the Netherlands. The study included 19 559 patients undergoing CIED procedures, 177 of whom developed an infection. Data were analyzed from April 5, 2021, to January 14, 2023. Exposures: Prospectively identified CIED infections. Main Outcomes and Measures: Time-dependent analysis of the timing (early [≤3 months] or delayed [3-12 months]) and extent (localized or systemic) of infection was performed to determine the risk of all-cause mortality associated with CIED infections. Results: Of 19 559 patients undergoing CIED procedures, 177 developed a CIED infection. The mean (SD) age was 68.7 (12.7) years, and 132 patients were male (74.6%). The cumulative incidence of infection was 0.6%, 0.7%, and 0.9% within 3, 6, and 12 months, respectively. Infection rates were highest in the first 3 months (0.21% per month), reducing significantly thereafter. Compared with patients who did not develop CIED infection, those with early localized infections were not at higher risk for all-cause mortality (no deaths at 30 days [0 of 74 patients]: adjusted hazard ratio [aHR], 0.64 [95% CI, 0.20-1.98]; P = .43). However, patients with early systemic and delayed localized infections had an approximately 3-fold increase in mortality (8.9% 30-day mortality [4 of 45 patients]: aHR, 2.88 [95% CI, 1.48-5.61]; P = .002; 8.8% 30-day mortality [3 of 34 patients]: aHR, 3.57 [95% CI, 1.33-9.57]; P = .01), increasing to a 9.3-fold risk of death for those with delayed systemic infections (21.7% 30-day mortality [5 of 23 patients]: aHR, 9.30 [95% CI, 3.82-22.65]; P < .001). Conclusions and Relevance: Findings suggest that CIED infections are most common within 3 months after the procedure. Early systemic infections and delayed localized infections are associated with increased mortality, with the highest risk for patients with delayed systemic infections. Early detection and treatment of CIED infections may be important in reducing mortality associated with this complication.