A pinboard by
Yaqiong Chai

Ph.D, research assistent, University of Southern California


Congenital heart disease (CHD) is the abnormal structure of the heart that is present at birth. Signs and symptoms are related to type and severity of the heart defect and usually presented early in childhood. Most devastating complications of CHD is cerebral incidents such as seizures, overt stroke and ischemic infarcts. Patients with CHD have lower intelligence scores and poorer academic achievements. Arterial spin labeling (ASL) MRI profiles brain perfusion using the protons in the arterial water of the feeding vessels of by magnetically labeling them using a series of radio frequency. There is then a delay for the labeled spins to flow through the vasculature and exchange magnetization with static tissue water (perfusion). The consequential change in tissue magnetization will be used to quantify cerebral blood flow (CBF). CBF has been reported to correlate with silent cerebral infarcts (SCIs) and decreased brain volume. However, it is unclear whether the altered CBF is on a regional basis, with the presence of known strokes in patients with CHD. Using traditional MRI images, we identified SCIs and strokes (in the form of abnormal signals on T2-weighted MRI images) with a neuroimaging toolbox; while using ASL, it is possible to quantitatively calculate the regional 3D CBF maps of the whole brain. The aim of the study is to determine the co-localization of known SCIs and CBF variations in 43 patients with CHD. As most medical imaging reports on CBF in CHD populations are for newborns, our patients have a wider age range (21-69 years) without open-heart surgery or neurosurgery. Therefore, it is possible to unveil the relationship between cerebral blood supply and the distribution of SCIs segmented from T2 images. We are not the first group to investigate the co-localization between SCIs and CBF, but we are the first to probe whether decreased CBF will predispose the patients to overt stroke or further SCIs in adults and the elder group. We expect the areas showing SCIs have very low CBF values as well as the areas at higher risk of neuronal death (SCI) but showing normal signals on T2 images. Our methods and results could also be beneficial to other populations given that SCIs are also very common in elderly patients with vascular disease, or any age group with chronic anemia, hypertension and sleep apnea. The methods and results may prove translational across these populations.