Biomedical subjects

M Onu

Publications and source records attributed to M Onu.

3 recordsLinked to original sources

PubMed2003

Functional magnetic resonance imaging at 0.2 Tesla.

Functional magnetic resonance imaging of healthy human volunteers was carried out at 0.2 T, using proton-density weighted (TE = 24 ms) spin-echo imaging, in order to eliminate any contribution from the blood oxygenation-level dependent (BOLD) effect. The purpose of the study was to verify the existence of a proton-density change contribution to spin-echo functional magnetic resonance imaging (fMRI) data. Results demonstrated signal intensity changes in motor and sensory areas of the brain during performance of a motor task and cold sensory stimulation of the hand, with signal changes ranging from 1.7 to 2.3%. These values are consistent with 1.9% signal changes observed previously under similar conditions at 3 T. These findings confirm the proton-density change contribution to spin-echo fMRI data and support the theory of signal enhancement by extravascular water protons (SEEP) as a non-BOLD fMRI contrast mechanism. This study also demonstrates that fMRI based on the SEEP contrast mechanism can be carried out at low fields where the BOLD effect is expected to be negligible.

Body Water↗

PubMed2001

Early MR changes in vertebral bone marrow for patients following radiotherapy.

Our study aimed to evaluate the vertebral marrow changes in patients following radiotherapy (RT) by measuring the T2 relaxation times before and during RT. We were mostly interested in evaluating early MR marrow changes during RT. Fifteen patients treated by RT for cervical cancer were submitted to MR examination before and during RT (5-23 days of RT). T2 values were calculated for irradiated and non-irradiated tissues (lumbar and sacral vertebral bone marrow, symphysis pubis marrow, and regional muscle). Fourteen patients presented increased T2 values for irradiated vertebral bone marrow (VBM), and 3 patients showed increased T2 values even for non-irradiated VBM. We found T2 variations for VBM as early as in the fifth day of RT for an absorbed dose as small as 9 Gy. Calculated T2 values in irradiated and also in non-irradiated tissues prove very early tissue alterations.

Adult↗

PubMedDate not supplied

[Nuclear stethoscopy. The clinical technic, methods and applications].

The paper reports on a new way of cardiological, radionuclidic investigation of the patients, a technique used for the first time in Romania. The technique and investigation method are presented in detail, with emphasis on some more important stages. As resulting from the description of the methodology, the performances of the left ventricle consist of three types of radioactivity/time curves at: first passage, beat by beat, and their summation. Of the advantages offered by the nuclear stethoscope, mention should be made that, besides the evaluation of systolic and diastolic parameters, it monitors the left ventricle functions in the rhythm disturbances, beat by beat, and being mobile, it permits the investigation at the patient's bed. Finally, the paper presents several cases investigated by the authors, and their special clinical applicability.

Coronary Disease↗