Comparison of two deep learning image reconstruction algorithms in chest CT images: A task-based image quality assessment on phantom data.

PURPOSE: The purpose of this study was to compare the effect of two deep learning image reconstruction (DLR) algorithms in chest computed tomography (CT) with different clinical indications. MATERIAL AND METHODS: Acquisitions on image quality and anthropomorphic phantoms were performed at six dose levels (CTDIvol: 10/7.5/5/2.5/1/0.5mGy) on two CT scanners equipped with two different DLR algorithms (TrueFidelityTM and AiCE). Raw data were reconstructed using the filtered back-projection (FBP) and the lowest/intermediate/highest DLR levels (L-DLR/M-DLR/H-DLR) of each algorithm. Noise power spectrum, task-based transfer function (TTF) and detectability index (d') were computed: d' modelled detection of a soft tissue mediastinal nodule, ground-glass opacity, or high-contrast pulmonary lesion. Subjective image quality of anthropomorphic phantom images was analyzed by two radiologists. RESULTS: For the L-DLR/M-DLR levels, the noise magnitude was lower with TrueFidelityTM than with AiCE from 2.5 to 10 mGy. For H-DLR, noise magnitude was lower with AiCE . For L-DLR and M-DLR, the average NPS spatial frequency (fav) values were greater for AiCE except for 0.5 mGy. For H-DLR levels, fav was greater for TrueFidelityTM than for AiCE. TTF50% values were greater with AiCE for the air insert, and lower than TrueFidelityTM for the polyethylene insert. From 2.5 to10 mGy, d' was greater for AiCE than for TrueFidelityTM for H-DLR for all lesions, but similar for L-DLR and M-DLR. Image quality was rated clinically appropriate for all levels of both algorithms, for dose from 2.5 to 10 mGy, except for L-DLR of AiCE. CONCLUSION: DLR algorithms reduce the image-noise and improve lesion detectability. Their operations and properties impacted both noise-texture and spatial resolution.

Arteriovenous fistulas thrombosis in hemodialysis patients with COVID-19.

BACKGROUND: The current Coronavirus disease 2019 (COVID-19) outbreak is associated with significant mortality, especially in patients suffering from end stage renal disease (ESRD) and hemodialysis patients. Several previous studies reported an over-risk of arterial and venous thrombosis, in particular pulmonary embolism and venous thrombosis of catheter in COVID19 patients in intensive care unit. However, arteriovenous fistula (AVF) thrombosis has rarely been reported yet in these patients. AVF thrombosis is a serious complication that impacts significantly patients outcome. Here, we aim to describe characteristics and prognosis of a cohort of COVID-19 hemodialysis (HD) patients presenting with AVF thrombosis. METHODS: In the Ile de France region (Paris area) during the March 11th-April 30th 2020 period, fistula thrombosis cases were collected among COVID-19 hemodialysis patients in seven dialysis units and in interventional vascular departments. These patients' characteristics were analyzed through a review of the patient's medical records. RESULTS: Seventeen patients were included in our study (median age 69 years). Ten patients (59%) were men. Ten patients (59%) were diabetic and 88% had a high blood pressure. The mortality rate in these patients was 47%. All thrombosis treated with a declotting procedures (64%) were successfully cleared, but with early relapse in 36%. CONCLUSION: Our study highlights AVF thrombosis as a severe complication in COVID-19 hemodialysis patients that contributed to the severity and accelerated death.

Endovascular treatment of acute complications associated with aortic dissection: midterm results from a multicenter study.

PURPOSE: To evaluate endovascular procedures in the management of acute ischemic complications and rupture of the false lumen in aortic dissections. METHODS: Data on patients with aortic dissection and noncardiac acute complications (peripheral ischemia or thoracic aortic rupture) treated with endovascular techniques were collected from 10 institutions and retrospectively analyzed. From March 1997 to January 2000, 58 patients (50 men; mean age 59.6+/-12.8 years) were treated for 19 (33%) type A and 39 (67%) type B dissections. Twelve (21%) patients had thoracic aortic rupture; 46 (79%) patients had one or more peripheral ischemic complications that included bowel pain (19, 41%), anuria associated with acute renal insufficiency (18, 39%), lower limb ischemia (15, 33%), and/or uncontrolled hypertension with renal ischemia (14, 30%). RESULTS: In the thoracic rupture cohort, all 12 patients were treated successfully with stent-grafts; one distal endoleak required a secondary procedure. There were 2 (12%) periprocedural deaths; one patient developed transient paraplegia after a secondary surgical procedure. In the 46 patients treated with stent implantation, fenestration, or both for peripheral ischemic symptoms, 44 (96%) had patency restored to the malperfused vessel. Eight (17%) patients died within 30 days. Over a mean follow-up of 8.2+/-8.9 months, the false lumen had thrombosed in 7 (70%) of the stent-graft patients. In the 38 surviving ischemic patients, the diameters of the true and false lumens and maximum transverse aorta all increased; only 4 (11%) had total thrombosis of the false lumen. CONCLUSIONS: Endovascular treatment of noncardiac acute complications associated with aortic dissection has favorable early and midterm outcomes.

Tratamiento endovascular de lesiones ateromatosas de miembros inferiores con prótesis de Palmaz / Treatment with Palmaz endovascular stent in atherosclerosis of inferior limb arteries

Entre julio de 1990 y junio de 1994 fueron tratados 310 pacientes en nuestro Servicio por una arteropatía de miembros inferiores. En 52 casos se utilizaron una o varias prótesis de Palmaz para completar o realizar dicho tratamiento. La cantidad total de endoprótesis de Palmaz colocadas en dicho período fue de 57, repartidas de la siguiente manera: ilíacas primitivas, 35; ilíacas externas, 10; femorales superficiales, 12. Las indicaciones las hemos clasificado en tres grupos: a) como complemento de una angioplastia percutánea (n=40); b) por reaparición a mediano plazo de una lesión ya tratada (n=7); c)como tratamiento de primera intención (n=10). El resultado inmediato fue óptimo en 56 casos (98,2 por ciento); en el caso restante (1,7 por ciento) el control angiográfico mostró la persistencia de una imagen de disección. La tasa de permeabilidad a largo plazo (1 año) fue del 87,5 por ciento con una tasa de reestenosis del 12,5 por ciento. El seguimiento a tres años mostró una permeabilidad del 61,1 por ciento. Las endoprótesis de Palmaz se revelan como un tratamiento eficaz de lesiones focales ateromatosas. Los resultados a largo plazo dependen de la hiperplasia miointimal (a nivel local) y de la evolutividad de la enfermedad ateromatosa