Biomedical subjects

I Lemahieu

Publications and source records attributed to I Lemahieu.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Two motion-detection algorithms for projection-reconstruction magnetic resonance imaging: theory and experimental verification.

In this paper, projection-reconstruction (PR) magnetic resonance (MR) imaging is considered. We present two new quantitative techniques that allow to check when motion was present during a PR MR experiment. No a priori information about the motion is required since only the measured MR signals are used in the calculations. Moreover, the proposed methods can be implemented on a standard personal computer or workstation. It is experimentally shown that both methods are able to detect motion intervals with an accuracy of one repetition time.

Artifacts↗

PubMedDate not supplied

Quantitative analysis of the neonatal brain by ultrasound.

Clinical research has shown a clear correlation between white matter disorders of the neonatal brain and neuromotoric handicap at a later age. Ultrasound imaging is a proven method to detect the white matter damage at an early stage. However, since subjective visual examination of the images by neonatologists not always leads to an unambiguous diagnosis, a need for quantitative characterization is felt. Reproducibility is the first requirement in order to be able to perform objective quantitative analysis. This paper proposes a software-based method to compensate for variable acquisition factors that negatively affect the reproducibility of the measurements. The results of some basic experiments will illustrate the usefulness of the developed compensation algorithm.

Algorithms↗

PubMedDate not supplied

Cobalt-55 positron emission tomography of ipsilateral thalamic and crossed cerebellar hypometabolism after supratentorial ischaemic stroke.

Cobalt-55 (55Co) is a positron emission tomography (PET) tracer used to demonstrate brain damage, possibly associated to calcium-mediated processes. The degree of 55Co accumulation correlates with the severity of ischaemia in stroke patients. It is still a matter of debate whether ipsilateral thalamic hypometabolism (ITH) and crossed cerebellar hypometabolism (CCH), occurring after middle cerebral artery (MCA) infarcts, represent only a metabolic depression of these remote regions or can lead to structural damage. The present study investigates whether an increased 55Co influx can be demonstrated with PET in ITH and CCH after MCA infarcts. About half of the patients with ITH and CCH had a significant degree of 55Co uptake in, respectively, the ipsilateral thalamus and the contralateral cerebellar hemisphere. It was observed in patients with severe signs of stroke on admission and poor clinical outcome, and correlated well with the degree of 55Co influx within the supratentorial infarct. The present study demonstrates that ITH and CCH after MCA infarction can represent structural damage in these remote areas that occurs during the second week after stroke onset.

Adult↗