MRI Reference Ranges for Fetal Cardiothoracic Ratio of Diameter, Area, and Circumference from 21 to 38 Weeks Gestational Age.

BACKGROUND: Whether fetal cardiothoracic ratio (CTR) is constant or increasing with gestational age (GA) is controversial. The majority of the fetal CTR data has been obtained through ultrasound. PURPOSE: To retrospectively analyze CTR of diameter, area, and circumference on prenatal MR images in a low-risk population of singleton pregnancies, and to clarify its diagnostic value. STUDY TYPE: Retrospective. SUBJECTS: 1024 low-risk singleton pregnancies undergoing MRI. FIELD STRENGTH: Balanced steady state free precession sequence and single shot-fast spin echo sequence at 1.5 Tesla. ASSESSMENT: Pregnancy clinical data were recorded and diameter, area, and circumference of the fetal heart and thorax were measured by two researchers with 6 and 7 years of radiology experience, respectively, and their variation with GA was investigated. The relationship between CTRs with GA was also investigated. Finally, the value of CTR in the diagnosis of fetuses with abnormal development was explored by using receiver operating characteristic (ROC) curves. STATISTICAL TESTS: Linear regression and ROC curves. A P value <0.05 was considered significant. RESULTS: There were significant positive linear correlations (R2 > 0.7, P < 0.0001) between the diameter, area, and circumference of the heart and thorax with GA. The CTRs remain constant values and do not change with GA. The 5th, 50th, and 95th percentiles of the CTR in 21-38 weeks GA were 0.32, 0.39, and 0.48 respectively. The corresponding percentiles for the area ratio were 0.15, 0.21 and 0.27, respectively, and for the circumference ratio were 0.40, 0.46, and 0.52, respectively. Based on ROC curves of CTR with three methods, the area under curves (AUCs) were up to 0.95, the sensitivity and the specificity were more than 88%. DATA CONCLUSION: Reference ranges of fetal CTR were established using MRI, which remain constant. These may be helpful in making a definitive diagnosis in fetuses with abnormal development. TECHNICAL EFFICACY: Stage 2.

Assessment of central nervous system vasculitis in children based on high-resolution vascular wall imaging.

Objectives: Central nervous system vasculitis (CNSV) is a rare disease. High-resolution vessel wall imaging (HR-VWI) enables the identification of inflammatory changes within the vessel wall. Few studies have applied HR-VWI to assess CNSV in children. This study delves into the utility of HR-VWI for diagnosing and treating CNSV in children, with the aim of enhancing clinical diagnosis and efficacy evaluation. Methods: Imaging data were acquired from children who underwent HR-VWI examinations. The study meticulously analysed clinical data and laboratory tests to discern the characteristics and distribution patterns of diverse vasculitis forms. Results: In children, CNSV mainly involves medium vessels with grade 1 and 2 stenosis (grade 4 stenosis is rare), and the imaging features generally show centripetal and moderate enhancement, suggesting that this feature is specific for the diagnosis of CNSV. High-grade stenosis, concentric enhancement and strong enhancement of the vasculature indicate more severe disease activity. Remarkably, HR-VWI proved to be significantly more sensitive than magnetic resonance angiography in detecting CNSV. Among the 13 cases subjected to imaging review, 8 demonstrated a reduction or resolution of vessel wall inflammation. In contrast, five patients exhibited worsening inflammation in the vessel wall. HR-VWI demonstrated that changes in vessel wall inflammation were closely correlated with changes in brain parenchymal lesions and symptoms. Conclusion: This study underscores the diagnostic value of HR-VWI in CNSV assessment and treatment monitoring, offering a quantitative evaluation of CNSV in children.

Normal reference values for magnetic resonance imaging measurements of the fetal internal jugular veins in middle and late pregnancy.

BACKGROUND: At present, there is a lack of normal magnetic resonance imaging (MRI) morphometric reference values for fetal internal jugular veins during middle and late pregnancy. OBJECTIVE: We used MRI to assess the morphology and cross-sectional area of the internal jugular veins of fetuses during middle and late pregnancy and to explore the clinical value of these parameters. MATERIALS AND METHODS: The MRI images of 126 fetuses in middle and late pregnancy were retrospectively analysed to determine the optimal sequence for imaging the internal jugular veins. Morphological observation of the fetal internal jugular veins in each gestational week was carried out, lumen cross-sectional area was measured and the relationship between these data and gestational age was analysed. RESULTS: The balanced steady-state free precession sequence was superior to other MRI sequences used for fetal imaging. The cross section of fetal internal jugular veins was predominantly circular in both the middle and late stages of pregnancy, however the prevalence of an oval cross section was significantly higher in the late gestational age group. The cross-sectional area of the lumen of the fetal internal jugular veins increased with increasing gestational age. Fetal jugular vein asymmetry was common, with the right jugular vein being dominant in the high gestational age group. CONCLUSION: We provide normal reference values for fetal internal jugular veins measured by MRI. These values may form the basis for clinical assessment of abnormal dilation or stenosis.

Quantitative Evaluation of a Cross-Sectional Area of the Fetal Straight Sinus by Magnetic Resonance Imaging and Its Clinical Value.

Objective: The intracranial venous system plays an important role in ensuring blood circulation and a stable blood supply to the fetal brain. In the present study, a cross-sectional area of the fetal straight sinus was quantitatively evaluated by fetal magnetic resonance imaging (MRI) to explore the method's clinical value. Methods: The clinical and MRI data of 126 normal fetuses in mid-to-late stage pregnancies were retrospectively analyzed. The "dominant" sequence of the fetal straight sinus was selected, and the cross-sectional area of the lumen was measured at each gestational age to obtain the normal range at different ages and to analyze the developmental pattern and characteristics of the fetal straight sinus. Results: There were statistically significant differences in the cross-sectional area of the fetal straight sinus among different gestational ages (P < 0.05). The cross-sectional area of the fetal straight sinus was positively correlated with gestational age (coefficient of determination = 0.6892, P < 0.05). That is, the cross-sectional area of the fetal straight sinus grew with increasing gestational age, and the regression equation was y = 0.27 x - 2.14 (P < 0.05). Additionally, there were five fetuses with cerebral venous abnormalities, including four with heart failure and one with venous sinus thrombosis. Conclusion: Quantitative measurement of a cross-sectional area of the fetal straight sinus by MRI enhanced understanding of the anatomical features and developmental pattern of fetal cerebral veins and provided a reference for the clinical diagnosis of related diseases and investigation concerning pathogenesis.