Magnetic resonance imaging quantitative T2* mapping to predict the red blood cell content of in vivo thrombi retrieved from patients with large vessel occlusions in acute ischemic stroke.

BACKGROUND AND PURPOSE: Magnetic resonance imaging quantitative T2* mapping has shown reliable identification of thrombus red blood cell content in vitro. The thrombus composition has been in vivo, associated with outcomes after endovascular therapy for acute ischemic stroke. We aim to analyze the red blood cell content of thrombi retrieved from patients with large vessel occlusions in relation to the thrombus-T2* relaxation time in magnetic resonance imaging. MATERIAL AND METHODS: Consecutive acute ischemic stroke patients treated by endovascular therapy were scanned with an magnetic resonance imaging quantitative T2* mapping sequence. Quantitative histologic evaluations of red blood cell content were performed. A linear regression assessed the association between vascular risk factors, comorbidities, antithrombotic drugs intake, baseline National Institutes of Health Stroke Scale (NIHSS), intravenous thrombolysis before endovascular therapy, time between onset and groin puncture, patient's outcome at 3 months, magnetic resonance imaging quantitative T2* mapping results, and the red blood cell content of thrombi. The correlation between the mean thrombus-T2* relaxation time and red blood cell content was assessed by calculating the Pearson correlation coefficient. RESULTS: Among 31 thrombi, 16 were "Fibrin rich" and 15 "red blood cell dominant." The median red blood cell content was 39 (range, 0-90; interquartile range, 37). The median (interquartile range) thrombus-T2* relaxation time was shorter in "red blood cell dominant" thrombi (21, interquartile range 6) than in "Fibrin rich" thrombi (24, interquartile range 7), without significant difference (p = 0.15), as shown in the Box plot. An inverse correlation between thrombus-T2* relaxation time and red blood cell content was found, with a correlation coefficient of -0.41 (95% CI, -0.67 to -0.08, p = 0.02). CONCLUSION: Our study shows that a shorter thrombus-T2* relaxation time is related to a higher red blood cell content within in vivo thrombi.

Angiographic findings and outcomes after embolization of patients with suspected postabortion uterine arteriovenous fistula.

INTRODUCTION: The purpose of this study is to assess the angiographic incidence of uterine arteriovenous fistula (UAVF) in women referred for a high ultrasonographic suspicion in a postabortion setting and to evaluate the safety, efficacy and impact on further fertility of uterine artery embolization (UAE) in this indication. MATERIALS AND METHODS: A monocentric retrospective study of 31patients managed by uterine artery embolization for suspected UAVF after spontaneous or induced first trimester abortion. The diagnosis of UAVF was confirmed when an early venous drainage was identified on the angiogram. Technical success was defined as complete exclusion of the vascular lesion. Clinical success was defined as the absence of bleeding during the clinical follow-up and during the surgery in case of hysteroscopic resection. Information about further fertility was gathered by phone calls to the patients. RESULTS: The mean age of the patients was 30.8 (±6.0) years. The diagnosis of UAVF was angiographically confirmed in 6 patients (19.4 %). Angiographic findings of retained product of conception (RPOC) with varying degrees of vascularity were observed in remaining patients. The technical success rate of UAE was 100 %, mostly through a proximal and bilateral embolization using a resorbable agent (27/31 patients, 87.1 %). The clinical success rate of UAE was 100 % in the group treated by a single UAE. We did not notice any bleeding during the surgery in the group of patients who needed a further hysteroscopic resection. 14 patients led at least one subsequent pregnancy to term without any difficulty. CONCLUSION: UAVF is a rare condition. We supposed it may constitute the ultimate stage in the natural history of the retained products of conception with "marked vascularity". UAE seems to be an effective and safe first-line treatment.