Quantification of cerebral blood flow using QUIPSSII pulsed arterial spin labeling requires that the QUIPSS saturation delay TI1 is shorter than the natural temporal bolus width. Yet the duration of the bolus of tagged spins entering the region of interest varies during vasoactive stimuli such as gaseous challenges or across subjects due to differences in blood velocity or vessel geometry. A ne...

AIM The harmful effect of hypocapnia on the neonatal brain emphasizes the importance of monitoring arterial carbon dioxide tension (PaCO2). Transcutaneous monitoring of carbon dioxide (tcPCO2) reduces the need for arterial blood sampling. Drawbacks are high electrode temperature causing risks of skin burning. The aim was to determine the accuracy and precision of tcPCO2 at reduced electrode tem...

UNLABELLED PET with short inhalation of (15)O-O(2) provides regional oxygen extraction fraction (OEF) in a shorter acquisition time and with less radiation exposure than does the steady-state method. The purpose of this study was to test the accuracy of the short-inhalation technique for estimating OEF in healthy human volunteers. METHODS The final study population included 16 healthy volunte...

False Aneurysms are uncommon in the pediatric population. We report a case of false aneurysm of the common femoral artery (CFA) after accidental arterial puncture, during a phlebotomy for blood sample. The lesion was surgically resected and arterial continuity restored by end to end anastomosis. The postoperative course was uneventful.

BACKGROUND AND PURPOSE Cerebral hemodynamics abnormality in Alzheimer disease (AD) is not fully understood. Our aim was to determine whether regional hypoperfusion due to AD is associated with abnormalities in regional arterial blood volume (rABV) and regional arterial transit time (rATT) as measured by quantitative arterial spin-labeling (ASL) with multiple-delay time sampling. MATERIALS AND...

BACKGROUND AND PURPOSE Acute anemia may lead to erroneously low arterial reference sample concentrations of radioactive microspheres, depending on the sampling rate and the size of the artery from which the reference samples are withdrawn. Because this error would lead to falsely high cerebral blood flow values in studies involving hemodilution caused by hemorrhage and fluid resuscitation, we s...

are based on the Stewart-Hamilton principle. Different types of indicators (dyes and radioisotopes) are used, and their varying concentrations are determined either from arterial sampled blood 1, 2 or by precordial scanning.3-9 Combined right and left heart catheterization provides a more direct measurement of pulmonary blood volume in man, by the indicator-dilution technic. In methods already ...

Lawson Health Research Institute, Department of Medical Biophysics, Western University, London, Ontario, Canada PET semi-quantitative methods such as relative uptake value can be robust but offer no biological information and do not account for intra-subject variability in tracer administration or clearance. Simultaneous multimodal measurements that combine PET and MRI not only permit crucial m...

INTRODUCTION Aim of this study was to reduce blood loss caused by diagnostic blood sampling and to minimize the development of anemia in a high-risk group of mechanically ventilated medical intensive care patients. We therefore implemented a "blood-saving bundle" (BSB) combining a closed-loop arterial blood sampling system, smaller sampling tubes, reduced frequency of blood drawings, and reduce...