Identification of infarct core and ischemic penumbra using computed tomography perfusion and deep learning.

Purpose: The size and location of infarct and penumbra are key to decision-making for acute ischemic stroke (AIS) management. CT perfusion (CTP) software estimate infarct and penumbra volume using contralateral hemisphere relative thresholding. This approach is not robust and widely contested by the scientific community. In this study, we investigate the use of deep learning-based algorithms to efficiently locate infarct and penumbra tissue on CTP hemodynamic maps. Approach: CTP scans were retrospectively collected for 60 and 59 patients in the infarct only and infarct + penumbra substudies respectively. Commercial CTP software was used to generate cerebral blood flow, cerebral blood volume, mean transit time, time to peak, and delay time maps. U-Net-shaped architectures were trained to segment infarct or infarct + penumbra. Test-time-augmentation, ensembling, and watershed segmentation were used as postprocessing techniques. Segmentation performance was evaluated using Dice coefficients (DC) and mean absolute volume errors (MAVE). Results: The algorithm segmented infarct tissue resulted in DC of 0.64 ± 0.03 (0.63, 0.65), and MAVE of 4.91 ± 0.94 (4.5, 5.32) mL. In comparison, the commercial software predicted infarct with a DC of 0.31 ± 0.17 (0.26, 0.36) and MAVE of 9.77 ± 8.35 (7.12, 12.42) mL. The algorithm was able to segment infarct + penumbra with a DC of 0.61 ± 0.04 (0.6, 0.63), and MAVE of 6.51 ± 1.37 (5.91, 7.11) mL. In comparison, the commercial software predicted infarct + penumbra with a DC of 0.3 ± 0.19 (0.25, 0.35) and MAVE of 9.18 ± 7.55 (7.25, 11.11) mL. Conclusions: Use of deep learning algorithms to assess severity of AIS in terms of infarct and penumbra volume is precise and outperforms current relative thresholding methods. Such an algorithm would enhance the reliability of CTP in guiding treatment decisions.

Persistent SARS-CoV-2 Alpha Variant Infection in Immunosuppressed Patient, France, February 2022.

We describe persistent circulation of SARS-CoV-2 Alpha variant in an immunosuppressed patient in France during February 2022. The virus had a new pattern of mutation accumulation. The ongoing circulation of previous variants of concern could lead to reemergence of variants with the potential to propagate future waves of infection.

CEST MRI provides amide/amine surrogate biomarkers for treatment-naïve glioma sub-typing.

PURPOSE: Accurate glioma classification affects patient management and is challenging on non- or low-enhancing gliomas. This study investigated the clinical value of different chemical exchange saturation transfer (CEST) metrics for glioma classification and assessed the diagnostic effect of the presence of abundant fluid in glioma subpopulations. METHODS: Forty-five treatment-naïve glioma patients with known isocitrate dehydrogenase (IDH) mutation and 1p/19q codeletion status received CEST MRI (B1rms = 2µT, Tsat = 3.5 s) at 3 T. Magnetization transfer ratio asymmetry and CEST metrics (amides: offset range 3-4 ppm, amines: 1.5-2.5 ppm, amide/amine ratio) were calculated with two models: 'asymmetry-based' (AB) and 'fluid-suppressed' (FS). The presence of T2/FLAIR mismatch was noted. RESULTS: IDH-wild type had higher amide/amine ratio than IDH-mutant_1p/19qcodel (p < 0.022). Amide/amine ratio and amine levels differentiated IDH-wild type from IDH-mutant (p < 0.0045) and from IDH-mutant_1p/19qret (p < 0.021). IDH-mutant_1p/19qret had higher amides and amines than IDH-mutant_1p/19qcodel (p < 0.035). IDH-mutant_1p/19qret with AB/FS mismatch had higher amines than IDH-mutant_1p/19qret without AB/FS mismatch ( < 0.016). In IDH-mutant_1p/19qret, the presence of AB/FS mismatch was closely related to the presence of T2/FLAIR mismatch (p = 0.014). CONCLUSIONS: CEST-derived biomarkers for amides, amines, and their ratio can help with histomolecular staging in gliomas without intense contrast enhancement. T2/FLAIR mismatch is reflected in the presence of AB/FS CEST mismatch. The AB/FS CEST mismatch identifies glioma subgroups that may have prognostic and clinical relevance.

[Capnocytophaga canimorsus: atypical septicemic meningitis, approach to microbiological diagnosis and therapeutic impact]. / Capnocytophaga canimorsus : méningite septicémique atypique, démarche du diagnostic microbiologique et impact thérapeutique.

Meningitis and septicaemia due to Capnocytophaga canimorsus are extremely rare and described as emerging zoonoses because of their low incidence and prevalence, but also because of the challenges in bacterial identification, thus, the real number of cases is probably underestimated. We report the case of a 61-year-old man, with a history a chronic alcoholism, who developed, following a recent dog bite, meningitis with normoglycorachia and concomitant sepsis, and had a favorable outcome after intravenous probabilistic antibiotherapy combining ceftazidime and metronidazole. This association aimed to cover the risks represented by Pseudomonas spp and anaerobic bacteria, once the microorganisms commonly associated with meningitis were excluded using molecular biology tools. In addition to the unusual biological results (normoglycorachia and bacterial morphology after Gram staining), we present the biological diagnostic approach (molecular, biochemical and physical tools successively used to lead, by exclusion and confirmation, to this diagnosis), closely linked to the clinical expertise. This is, to our knowledge, the first described case of meningitis with normoglycorachia and septicaemia due to Capnocytophaga canimorsus successfully treated with ceftazidime and confirmed by identification by MALDI-TOF mass spectrometry.

Detection of different classes of carbapenemases: Adaptation and assessment of a phenotypic method applied to Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and proposal of a new algorithm.

A new phenotypic method for detecting carbapenemases has been adapted (assembling of two MAST® kits, including one that contains faropenem to which a temocillin disk has been added) then assessed using 101 bacterial strains (Enterobacteriaceae with assays on Pseudomonas aeruginosa and Acinetobacter baumannii) including 62 which produce genetically identified carbapenemases. Concerning Carbapenemase-Producing Enterobacteriaceae (CPE), there is 100% sensitivity for Klebsiella pneumoniae carbapenemase (KPC, Ambler class A) and OXA-48 (Ambler class D), and 91% for metallo-beta-lactamase (MBL, Ambler class B), with a 97% sensitivity for all carbapenemases, with a specificity of 100%. The test is also efficient for detecting Pseudomonas aeruginosa carbapenemases (sensitivity between 82 and 100% and 100% specificity). The major innovation is the combined use of faropenem and temocillin for reliable detection (excellent performance with 100% sensitivity and specificity) of OXA-48. This study has led to the development of a new algorithm to detect the different classes of carbapenemases, for first-line diagnosis, by combining this modified MAST® test with immunochromatographic methods and molecular biology techniques.

ALS with respiratory onset: clinical features and effects of non-invasive ventilation on the prognosis.

Respiratory muscle involvement is one of the main prognostic factors in amyotrophic lateral sclerosis (ALS). Acute respiratory failure is sometimes the first manifestation of the disease, although onset can be more insidious. In the present retrospective study, it was proposed to review the clinical features and to assess the effects of non-invasive ventilation (NIV) on the prognosis of patients with respiratory onset, which was taken to be present when the first symptoms of muscular weakness were dyspnoea at exertion, dyspnoea at rest, or orthopnoea. Respiratory onset ALS is uncommon, since it accounts for less than 3% of ALS cases. ALS with respiratory onset has some common clinical features: male predominance, frequent camptocormia or dropped head, frequent widespread fasciculations, limb mobility fairly well preserved and significant weight loss in the early stages. ALS patients with respiratory onset still have a poor prognosis compared with those with bulbar or spinal forms. NIV should be proposed promptly because it improves the symptoms, general state of health and survival time. Efforts should be made to inform general practitioners and chest physicians and remind them that neuromuscular respiratory insufficiency may be attributable to this particular form of ALS.

Prospective evaluation of nonenhanced MR imaging in acute pancreatitis.

PURPOSE: To compare the value of nonenhanced (NE) magnetic resonance imaging (MRI) (NE-MRI) with contrast-enhanced (CE) computed tomography (CT) (CE-CT) scan in assessing acute pancreatitis (AP) and in evaluating the severity index (SI) with clinical outcome. MATERIALS AND METHODS: Patients with AP were prospectively investigated by CE-CT scan and NE-MRI on admission. MRI was performed with fat-saturated T1-weighted imaging, T2-weighted imaging, and MR cholangiopancreatography (MRCP). Balthazar's grading system was used to evaluate the NE-MRI severity index (CTSI, MRISI) and it was compared to the clinical outcome. RESULTS: A total of 90 patients (median age = 55 years) were included in the study. AP was of biliary etiology in 37 patients (41%). On admission, AP was assessed as grade III by CTSI in four patients (4%), whereas 19 patients were classified grade III by MRISI. The coefficient correlation between CTSI and MRISI was good, with r = 0.6 (P < 0.001). Considering CE-CT scan as the gold standard, sensitivity (Sn), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of NE-MRI for detecting severe AP based on imaging criteria were 100%, 82.6%, 100%, and 21%, respectively. NE-MRI discriminates normal pancreatic parenchyma from edema and necrosis with a correlation between morbidity (P < 0.008). CONCLUSION: NE-MRI seems to be a reliable method of staging AP severity in comparison to CE-CT scan.

Hereditary hemorrhagic telangiectases: magnetic resonance imaging features in liver involvement.

In hereditary hemorrhagic telangiectasia (HHT), the liver demonstrates a large pattern of findings, including telangiectases, arteriovenous shuntings, focal liver lesions, and ischemic cholangitis, and provides severe complications such as portal hypertension and cardiac failure. Magnetic resonance imaging allows obtaining complete information (parenchyma, biliary tract, and vessels) of the liver in a 1-step examination. Acknowledgment of typical magnetic resonance imaging features of liver involvement in hereditary hemorrhagic telangiectasia case will result in more accurate diagnosis and can guide therapeutic options.

Mangafodipir-enhanced magnetic resonance cholangiography for the diagnosis of bile duct leaks.

BACKGROUND: The purpose of this prospective study was to assess the value of contrast-enhanced magnetic resonance cholangiography with mangafodipir trisodium perfusion for detection and localization of trauma-induced and postoperative bile duct leaks. METHODS: Eleven patients with suspected bile duct leaks after trauma (n=5) or surgery (n=6) were included. Patients with suspected leaks after cholecystectomy were excluded. All patients underwent contrast-enhanced magnetic resonance cholangiography with two-dimensional axial and three-dimensional coronal gradient-echo images acquired 1 to 3 hours after intravenous administration of mangafodipir trisodium perfusion. Contrast-enhanced magnetic resonance cholangiography findings were correlated with direct cholangiography obtained in all patients, including endoscopic retrograde (n=7) and percutaneous transhepatic cholangiography (n=4). RESULTS: Biliary tract enhancement was identified in all patients on contrast-enhanced magnetic resonance cholangiography. Peritoneal cavity fluid and bile collections that contained extravasated mangafodipir trisodium (increased signal intensity on gradient-echo sequences) were demonstrated in 6 patients. Direct cholangiography confirmed the presence of bile duct leaks in these 6 patients and the absence of bile duct leaks in 5 patients. There was no false-negative or false-positive contrast-enhanced magnetic resonance cholangiography. CONCLUSIONS: Mangafodipir-enhanced magnetic resonance cholangiography is a noninvasive technique that can provide functional biliary information with excellent depiction of bile duct leaks.

Contribution of magnetic resonance cholangiopancreatography to the management of patients with suspected common bile duct stones.

OBJECTIVES: To evaluate the value of magnetic resonance cholangiography (MRC) as a systematic first-line investigation in the management of patients with suspected common bile duct stones. METHODS: Ninety-nine consecutive patients with clinical suspicion of choledocolithiasis were prospectively explored by MRC. All MRCs were interpreted by two radiologists with knowledge of the patient's clinical condition and laboratory results. In case of discrepancy, a third opinion was obtained to reach consensus. The definitive diagnosis was established on the basis of endoscopic exploration of the common bile duct (n=40), clinical and biological follow-up at 6 Months (n=55) or other investigations (n=4). The clinician's level of confidence, management options implemented, and impact of management decisions were used to assess the contribution of MRC. The diagnostic accuracy of MRC for common bile duct stones was also determined. RESULTS: At the observed level of confidence (85.9%), MRC identified a differential diagnosis in 7.1% of patients avoiding unnecessary endoscopic exploration in 59.6%. Systematic first-line MRC enabled appropriate management in 83.8% of patients. The sensitivity, specificity, and positive and negative predictive values of MRC for the diagnosis of common bile duct stones were 95.7%, 98.7%, 95.7% and 98.7%, respectively, with excellent inter-observer agreement (kappa=0.915). CONCLUSION: Magnetic resonance cholangiography can be used to efficiently screen patients who may need further invasive exploration of the common bile duct. It specifically identifies patients requiring therapeutic ERCP.