title: In vivo quantification of intraventricular hemorrhage in a neonatal piglet model using an EEG-layout based electrical impedance tomography array.
abstract: Intraventricular hemorrhage (IVH) is a common occurrence in the days immediately after premature birth. It has been correlated with outcomes such as periventricular leukomalacia (PVL), cerebral palsy and developmental delay. The causes and evolution of IVH are unclear; it has been associated with fluctuations in blood pressure, damage to the subventricular zone and seizures. At present, ultrasound is the most commonly used method for detection of IVH, but is used retrospectively. Without the presence of adequate therapies to avert IVH, the use of a continuous monitoring technique may be somewhat moot. While treatments to mitigate the damage caused by IVH are still under development, the principal benefit of a continuous monitoring technique will be in investigations into the etiology of IVH, and its associations with periventricular injury and blood pressure fluctuations. Electrical impedance tomography (EIT) is potentially of use in this context as accumulating blood displaces higher conductivity cerebrospinal fluid (CSF) in the ventricles. We devised an electrode array and EIT measurement strategy that performed well in detection of simulated ventricular blood in computer models and phantom studies. In this study we describe results of pilot in vivo experiments on neonatal piglets, and show that EIT has high sensitivity and specificity to small quantities of blood (<1 ml) introduced into the ventricle. EIT images were processed to an index representing the quantity of accumulated blood (the 'quantity index', QI). We found that QI values were linearly related to fluid quantity, and that the slope of the curve was consistent between measurements on different subjects. Linear discriminant analysis showed a false positive rate of 0%, and receiver operator characteristic analysis found area under curve values greater than 0.98 to administered volumes between 0.5, and 2.0 ml. We believe our study indicates that this method may be well suited to quantitative monitoring of IVH in newborns, simultaneously or interleaved with electroencephalograph assessments.
authors.affiliation: Department of Psychology, Florida State University, Tallahassee, FL, USA.
authors.forename: Te
authors.initials: T
authors.lastname: Tang
authors.forename: Michael D
authors.initials: MD
authors.lastname: Weiss
authors.forename: Peggy
authors.initials: P
authors.lastname: Borum
authors.forename: Sergei
authors.initials: S
authors.lastname: Turovets
authors.forename: Don
authors.initials: D
authors.lastname: Tucker
authors.forename: Rosalind
authors.initials: R
authors.lastname: Sadleir
mesh_terms: D000465:Algorithms; D000818:Animals; D000831:Animals, Newborn; D019540:Area Under Curve; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging* / Q000473:pathology; D002552:Cerebral Ventricles / Q000000981:diagnostic imaging* / Q000473:pathology; D016002:Discriminant Analysis; D004195:Disease Models, Animal; D017097:Electric Impedance; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation*; D005189:False Positive Reactions; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007235:Infant, Premature, Diseases / Q000000981:diagnostic imaging*; D016014:Linear Models; D011379:Prognosis; D012372:ROC Curve; D013552:Swine; D014054:Tomography / Q000295:instrumentation* / Q000379:methods*