Document Detail

Changes in myometrial 'perfusion' during normal labor as visualized by three-dimensional power Doppler angiography.
MedLine Citation:
PMID:  19204911     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Myometrial contractions are one of the most important aspects of effective labor. For cells within the myometrium to work efficiently they need to be well oxygenated and this requires an adequate blood supply. This study used quantitative three-dimensional (3D) power Doppler angiography to calculate the percentage change in myometrial blood flow during a relaxation-contraction-relaxation cycle of active labor. METHODS: Transabdominal 3D power Doppler ultrasound imaging was used to acquire volumetric data during the first stage of spontaneous labor in 20 term, nulliparous women. 3D datasets were acquired during a single cycle of uterine relaxation, contraction and subsequent relaxation for each subject. The resultant datasets were analyzed independently by two investigators on two occasions using Virtual Organ Computer-aided AnaLysis to define a volume of interest within the myometrium; the power Doppler signal within this volume was quantified to provide 3D indices of vascularity: vascularization index (VI), flow index (FI) and vascularization flow index (VFI). The percentage change in these indices, during a uterine contraction, was calculated from the baseline value during the initial uterine relaxation phase (taken as a maximum of 100%). RESULTS: Myometrial blood flow fell significantly during the uterine contraction and returned during the subsequent relaxation phase of the cycle (P < 0.001 for VI and VFI, P = 0.002 for FI). From the initial baseline relaxation value, VI dropped to 43.9%, FI to 85.5% and VFI to 40.8% during uterine contraction, and returned to 86.7%, 98.1% and 89.1%, respectively, during the subsequent relaxation. The intraclass correlation coefficients in blood flow measurements of 0.982-0.999 between the two investigators were indicative of good interobserver reliability. CONCLUSIONS: This study confirms that myometrial perfusion, as measured by quantitative 3D power Doppler angiography, significantly falls during uterine contractions, returns during the subsequent relaxation phase, and can be quantified reliably from stored datasets. Further work is now required to establish clinical applicability for this non-invasive investigation.
N W Jones; N J Raine-Fenning; K Jayaprakasan; H A Mousa; M J Taggart; G J Bugg
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology     Volume:  33     ISSN:  1469-0705     ISO Abbreviation:  Ultrasound Obstet Gynecol     Publication Date:  2009 Mar 
Date Detail:
Created Date:  2009-03-04     Completed Date:  2010-02-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9108340     Medline TA:  Ultrasound Obstet Gynecol     Country:  England    
Other Details:
Languages:  eng     Pagination:  307-12     Citation Subset:  IM    
Copyright Information:
(c) 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Department of Obstetrics and Gynaecology, Directorate of Family Health, Nottingham University Hospitals NHS Trust, Nottingham, UK.
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MeSH Terms
Angiography / methods
Blood Flow Velocity / physiology
Gestational Age
Imaging, Three-Dimensional / methods
Labor Stage, First / physiology
Myometrium / blood supply*,  physiopathology,  radiography
Prospective Studies
Ultrasonography, Prenatal / methods
Uterine Contraction / physiology*

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