Feasibility of an Automatic Ultrasonographic Image Acquisition System Associated With an Artificial Intelligence Algorithm for Real-Time Monitoring of Cardiac Motion During Cardiac Radio-Ablation

Background

The management of the cardio-respiratory motion of the target and the reduction of the uncertainties related to patient's positioning are two of the main challenges that stereotactic arrhythmia radio-ablation (STAR) has to overcome. A prototype of a system was developed that can automatically acquire and interpret echocardiographic images using an artificial intelligence (AI) algorithm to calculate cardiac displacement in real-time.

Methods

We conducted a single center study enrolling consecutive patients with a history of ventricular arrhythmias (VA) in order to evaluate the feasibility of this automatic acquisition system. Echocardiographic images were automatically acquired from the parasternal and apical views with a dedicated probe. The system was designed to hold the probe fixed to the chest in the supine position during both free-breathing and short expiratory breath-hold sequences, to simulate STAR treatment. The primary endpoint was the percentage of patients reaching a score ≥2 in a multi-parametric assessment evaluating the quality of automatically acquired images. Moreover, we investigated the potential impact of clinical and demographic characteristics on achieving the primary endpoint.

Results

We enrolled 24 patients (63 ± 14 years, 21% females). All of them had a history of VA and 21 (88%) had an ICD. Eight patients (33%) had coronary artery disease, 12 (50%) had non-ischemic cardiomyopathy, and 3 had idiopathic VA. Parasternal, as well as apical images were obtained from all patients except from one, in whom parasternal view could not be collected due to the patient's inability to maintain the supine position. The primary endpoint was achieved in 23 patients (96%) for the apical view, in 20 patients (87%) for the parasternal view, and in all patients in at least one of the two views. The images' quality was maximal (i.e., score = 4) in at least one of the two windows in 19 patients (79%). Atrial fibrillation arrhythmia was the only clinical characteristics associated with a poor score outcome in both imaging windows (apical p = 0.022, parasternal p = 0.014).

Conclusions

These results provide the proof-of-concept for the feasibility of an automatic ultrasonographic image acquisition system associated with an AI algorithm for real-time monitoring of cardiac motion in patients with a history of VA.

Réponse à la vaccination contre le SARS-CoV-2 chez des patients hémodialysés chroniques

Introduction

Les patients hémodialysés chroniques (HDC) sont à haut risque de développer une forme grave d’infection à SARS-CoV-2. Ils constituent une population cible pour la vaccination. Toutefois, la réponse vaccinale chez ces patients n’est pas connue.

Matériels et méthodes

Étude observationnelle monocentrique portant sur l’ensemble des patients HDC à qui la vaccination contre la COVID-19 par le vaccin à ARNm BNT162b2 (Pfizer–BioNTech®) a été proposée. Deux injections ont été réalisées à 28 j d’intervalle, dans le bras opposé à l’abord vasculaire. Les données cliniques ont été recueillies prospectivement. La recherche d’anticorps spécifiques (IgG et IgM anti-protéine Spike) a été réalisée par immunochromatographie (COVID-19 BSS, Biosynex®) sur des sérums collectés avant la première injection, puis avant la seconde et 1 mois après. Les résultats sont exprimés en médiane [IQR : 25–75] ou %.

Résultats

Entre le 15 janvier et le 21 mars 2021, la vaccination a été proposée aux 55 patients du centre et acceptée par 49 (89,1 %) patients, les 6 autres ayant refusé. Parmi les 49 patients vaccinés, l’âge médian est de 70 [63–82,5] ans, 17 (34,7 %) sont diabétiques, et 8 (16,3 %) ont une greffe d’organe solide. La durée médiane en dialyse à la vaccination est de 26,2 [17,8–49,9] mois ; les patients sont dialysés sur une membrane en polysulfone (PSF), sauf 4 (8,2 %) sur une membrane en polyméthylmétacrylate (PMMA).

La séroprévalence en IgG à j0 est de 12,2 % (6/49 patients, dont 4 ayant un antécédent de COVID symptomatique de plus de 3 mois, avec PCR positive). Parmi les 43 patients séronégatifs à l’inclusion, 10 sont encore en cours de vaccination. Les 33 patients ayant complété le schéma vaccinal ont les résultats suivants, respectivement avant la seconde injection et 1 mois après : IgM, 9,1 % (3 patients) et 12,1 % (4 patients) ; IgG, 9,1 % (3 patients) et 87,9 % (29 patients).

Tous les patients positifs en IgM le sont également en IgG (aucun n’a développé de signes cliniques évocateurs de COVID-19 dans le suivi). Parmi les 4 patients non répondeurs, 1 recevait une immunothérapie pour cancer cutané, et tous ont une membrane en PSF. Tous les patients transplantés d’organe ont eu une réponse vaccinale positive 1 mois après la seconde injection. Le profil sérologique des patients dialysés avec un filtre en PMMA est comparable à ceux avec un filtre en PSF. La tolérance est bonne: 1 patiente a présenté une réponse systémique avec fièvre et frisson, et 60,1 % ont eu une réaction douloureuse au point d’injection ayant duré 24 h.

Conclusion

L’acceptation et la réponse vaccinale au vaccin à ARNm contre la COVID-19 sont bonnes chez les patients HDC.

GEC-ESTRO/ACROP recommendations for quality assurance of ultrasound imaging in brachytherapy

Ultrasound (US) is an important imaging modality in brachytherapy (BT). In particular for low-dose-rate (LDR) and high-dose-rate (HDR) prostate implants transrectal ultrasound (TRUS) is widespread. Besides the common use of US for prostate implants, US can also be applied in gynecological and anal cancer therapies as examples amongst others. The BRAPHYQS (BRAchytherapy PHYsics Quality assurance System) and UroGEC (urology) working groups of GEC-ESTRO (GEC: Groupe Européen de Curiethérapie, committee of ESTRO: European SocieTy for Radiotherapy & Oncology) elaborated upon guidelines describing quality assurance (QA) methods for US in BT. The total quality management (QM) for the unit includes acceptance testing, commissioning and periodic image testing. In 2008, the AAPM (American Association of Physicists in Medicine) published the TG (Task group) 128 report. Whereas the TG 128 focuses on US systems and prostate BT, the current recommendations also cover tests for stepping devices and include other interstitial or intracavitary treatment sites in BT, such as anal implants and gynecological BT. The recommendations presented herein do not replace regular maintenance for the US devices performed by the vendor. They are the QA of US in BT but are not sufficient for the whole maintenance of medical US devices. Moreover, national regulations and recommendations should also be followed. For the tests presented in this report tolerances or action limits are given. These recommendations explain practical test procedures of US devices in BT. They will help the clinics to perform a high level of quality in the use of US for BT in Europe.

Chemotherapy in non-selected elderly patients: Factors influencing dose-intensity and toxicity

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Background: Chemotherapy (CT) is the treatment of choice for most metastatic cancers. Frequent functional impairment and comorbidities in the elderly increase the risk of chemotherapy-related acute complications. The applicability of clinical trials data to the elderly population is exposed to multiple bias. Informations extracted from non-selected treated patients (pts) may be useful. Methods: A serie of consecutive elderly cancer pts (>73 years) treated over 3 years in the oncology outpatient unit, and receiving CT were included for analysis and assessed using prechemotherapy evaluation of cancer in the elderly (including performance status, comorbidities, glomerular filtration rate, liver tests, hemogram, nutritional status, inflammation tests). Relationship between preCT evaluation and acute complications, unscheduled hospitalisation, mortality were investigated by univariate analyses. Comparison between planned and realised dose- intensity of CT protocols could be extracted for the CT prescription software. Results: 108 pts with a median age of 78 years (73- 89; 44% over 80) were identified. Characteristics included performance status (PS) ≥ 2 (44%), chronic renal insufficiency (47%) ; ≥2 comorbidities (75%). Primary tumour was urologic (31%), gastro-intestinal (29%), mammary and gynaecologic (20%); pulmonary (16%) or other (4%). Disease stage was metastatic for 82% of pts. Most CT regimens contained a platinum derivative (55%), gemcitabine (25%), 5-FU (20%), taxanes (17%), vinorelbine (15%). Transfusion requirements were higher in PS≥2 pts (p<0.0001). Febrile neutropenia correlated with PS, lymphocytopenia and PINI =(CRP×AAG)/(albumin×pre-albumin)>10 (p<0. 05). Unscheduled hospitalisation correlated with PS, lymphocytopenia, PINI, more than 2 co-morbidities, more than 4 co-medications. Oxaliplatin- and paclitaxel-containing CT protocols were associated with significant reduction of dose-intensity because of reduced number of cycles due to neurosensory toxicity (p=0.01). Conclusions: Lymphocytopenia, PS, and PINI were the most relevant prognosticators of short-term CT outcome. Elderly pts characteristics are associated with higher risk of acute toxicity and increased sensitivity to neurosensory cumulative toxicity.

No significant financial relationships to disclose.

Simplified activity evaluation of several tetanus vaccines

The activity of several Tetanus Toxoids, Adsorbed, (commercial vaccines and references) were tested in mice in comparison with a standard, by a simple method, easier than the official challenge test (WHO and European Pharmacopoeia): the Tetanus Antitoxin level was titrated by agglutination of sensitized turkey red blood cells after immunization by the toxoids. Immuno-stimulation by the Pertussis component in associated vaccines was studied and the results with the conventional and the acellular Pertussis preparations were prepared. The method was also found to be suitable for Tetanus Toxoids, Non-Adsorbed, when a booster effect was used, except for the adjuvant-free polymerized antigen (POLAN) which did not require a booster, since it gave almost as good results as conventional adsorbed tetanus vaccines.

[A simple method for assaying the activity of adsorbed tetanus toxoids]

The authors have developed a simplified activity test for Tetanus Toxoids Adsorbed, based on the comparison of antitoxin levels in mice 4 weeks after injection of a reference toxoid and of the vaccine to be tested. Titration of tetanus antitoxin is achieved by passive agglutination of turkey RBC sensitized by means of glutaraldehyde. After preliminary experiments establishing feasibility of this method, the authors have obtained reproducible and quantitative results. They observed an increase of the immune response by a booster and an immunostimulation when pertussis component is present. They have found close correlation in immunized mice between the titre of circulating antibodies and the survival/death response after challenge by tetanus toxin as done in the official control. This simplified method using a reduced number of animals, yields, nevertheless, quantified results with confidence limits. Thus it is suitable for laying down a norm and can in many cases take the place of the official potency test which is tedious, expensive and often criticized.