Positron emission tomography and its role in the assessment of vulnerable plaques in comparison to other imaging modalities

The diagnosis and management of vulnerable plaques are topics of high interest in the cardiovascular field. Although imaging techniques like computed tomography angiography (MCTA) and ultrasonography (USG) can structurally evaluate atherosclerotic plaques, they are limited in examining internal cellular processes. Positron emission tomography (PET) molecular imaging, on the other hand, can highlight these cellular processes, including inflammation, angiogenesis, and lipid oxidation. Magnetic resonance imaging (MRI) is also a valuable non-invasive imaging technique that can provide detailed anatomical and functional information on the cardiovascular system. In this review, we compare the advantages and drawbacks of MCTA, USG and MRI imaging techniques with PET molecular imaging in evaluating vulnerable plaques. PET imaging allows physicians to measure different pathophysiological events within the plaque using intravenous radiotracers, of which 18F-fluorodeoxyglucose (18F-FDG) is the most validated one. By using 18F-FDG, physicians can understand the formation of the plaque, assess the accumulation of macrophages, and predict major cardiovascular events. However, some limitations exist in using 18F-FDG, including myocardial uptake and low sensitivity in imaging coronary arteries. We also mention other radiotracers that can help in evaluating vulnerable plaques, including 18F-NaF. Although PET imaging is still challenging, it has shown promise in evaluating vulnerable plaques and could be used to intervene in high-risk patients before major cardiovascular events occur.

Perinatal outcomes of fetoscopic laser surgery for twin-twin transfusion syndrome in triplet pregnancy: cohort study, systematic review and meta-analysis

OBJECTIVES

The aims of this study were to investigate the perinatal outcome of dichorionic triamniotic (DCTA) and monochorionic triamniotic (MCTA) triplet pregnancies complicated by twin-twin transfusion syndrome (TTTS) treated with fetoscopic laser photocoagulation (FLP) in two academic fetal centers, and to conduct a systematic review of previously published data to investigate perinatal survival in this targeted population.

METHODS

The first part of the study was a retrospective cohort study of prospectively collected data of consecutive triplet pregnancies with TTTS that underwent FLP at two fetal treatment centers between 2012 and 2020. Demographic, preoperative and operative variables and postoperative outcome were collected. Perinatal outcomes were investigated. The second part of the study was a systematic review and meta-analysis of studies evaluating the outcome of DCTA and/or MCTA triplet pregnancies, including our cohort study. PubMed, Web of Science and Scopus were searched from inception to September 2020. Primary outcomes were fetal survival (survival to birth), neonatal survival (survival to 28 days of age) and gestational age (GA) at birth.

RESULTS

A total of 31 sets of triplets with TTTS managed with FLP were included in the cohort study. Of these, 24 were DCTA and seven were MCTA. There were no significant differences in preoperative and operative variables between the two groups. There were also no significant differences between groups in GA at delivery or perinatal survival rate, including fetal and neonatal survival of at least one triplet, at least two triplets and all three triplets. Nine studies, including our cohort study, were included in the systematic review (156 DCTA and 37 MCTA triplet pregnancies treated with FLP). The overall fetal and neonatal survival was 79% (95% CI, 75-83%) and 75% (95% CI, 71-79%), respectively, in DCTA cases and 74% (95% CI, 52-92%) and 71% (95% CI, 49-89%), respectively, in MCTA cases. The rate of preterm birth before 28 weeks and before 32 weeks' gestation was 14% (95% CI, 4-29%) and 61% (95% CI, 50-72%), respectively, in DCTA triplets and 21% (95% CI, 3-45%) and 82% (95% CI, 62-96%), respectively, in MCTA triplets.

CONCLUSIONS

Triplet pregnancies with TTTS are at high risk of adverse perinatal outcome and preterm birth, regardless of chorionicity. The rate of survival after FLP in MCTA triplets was higher in our study than that reported in previous studies and is currently comparable with survival in DCTA triplets, which could be due to improved surgical skills. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

CT Imaging of Acute Ischemic Stroke [Formula: see text]

Although acute ischemic stroke remains one of the most common causes of death and disability worldwide, it is a potentially treatable condition if appropriately managed in a timely manner. The goals of acute stroke imaging include establishing a diagnosis as fast as possible with (1) accurate infarct quantification, (2) intracranial and cervical vasculature assessment, and (3) brain perfusion analysis for detection of infarct core and potentially salvageable penumbra allowing optimal patient selection for appropriate therapy. Given the extensive number of images generated from acute stroke imaging studies and as "time is brain," this article aims to highlight a logical approach for the radiologist in acute stroke computed tomography imaging in order to accurately interpret and communicate results in a timely manner.