Search PubMed⌕ Search

Biomedical subjects

M Oudkerk

Publications and source records attributed to M Oudkerk.

133 records · Page 8Linked to original sources
PubMedDate not supplied

Basic principles of magnetic resonance imaging.

Magnetic resonance imaging (MRI) is a noninvasive imaging technique that is becoming more and more important in clinical cardiology. Physicians must understand the basic principles of MRI before reliable use in practice is possible. Therefore, we will give an introduction to basic MRI principles necessary to understand the difficulties of cardiac MRI. First the generation of a signal by the combination of a strong magnetic field, radiofrequency pulses, and temporary changes in the magnetic field is explained. Then, the processes of localization of different points in an image, resolution, and signal-to-noise ratio are highlighted. Finally, the influence of tissue characteristics such as T1 and T2 on the contrast of an image are discussed.

Cardiovascular Diseases↗
PubMedDate not supplied

Magnetic resonance imaging of the coronary arteries: techniques and results.

Recently a new noninvasive imaging technique, magnetic resonance imaging (MRI) has been developed that has the potential to assess the coronary arteries. MRI of the coronary arteries is a challenging task because of the motion of the vessels during cardiac contraction and the motion of the heart with respiration. Several two-dimensional and three-dimensional acquisition techniques have been developed to overcome these problems. In this article we will describe different conventional MR techniques such as spin-echo and gradient-echo imaging. Also, we will describe new developments in MRI as ultrafast breathhold techniques using echo planar imaging or targeted volume scanning. Other new developments are respiratory gating techniques with or without respiratory motion correction. Finally, we will review the results of these techniques in the detection of coronary artery bypass graft patency, coronary artery stenosis, and the evaluation of coronary artery anomalies.

Coronary Artery Disease↗
PubMedDate not supplied

CT-guided bone biopsy in a cancer center: experience with a new apple corer-shaped device.

In this article we report our experience with CT-guided bone biopsy (CTGBB) using a new nondisposable bone biopsy device with in a uniform protocol for all lesions and compare our results with data from bone biopsies obtained with other techniques. With this biopsy device, the specimen is collected in a 20 x 2 mm chamber of an apple corer-shaped needle. In 46 consecutive cancer patients that were candidates for bone biopsy, 50 CTGBB procedures were performed and analyzed. Lesions with cortical defects and/or surrounding soft tissue infiltration were excluded. There were no complications. Of 50 CTGBB procedures, 90% were diagnostic. Four of the five inconclusive biopsies were repeated: All were conclusive, one malignant. Of 19 with CT-indistinguishable lesions (detected on MRI or isotope studies), 35% were malignant. Thirty-eight percent of the lesions were not accompanied by pain. The procedure was less painful than injection of the local anesthetic prior to biopsy in 90% of the cases. With the new device, CTGBB procedures can be carried out safely. Biopsy with the described technique has a high diagnostic output, better results than those of biopsy with reported uniform techniques, and equal results to the best results of combined techniques. If a lesion is not distinguishable on CT and/or not accompanied by pain, malignancy is not ruled out. CTGBB in the described technique is less or equally time consuming, less painful, and cheaper than reported for other bone biopsy procedures.

Adult↗
PubMedDate not supplied

CASCADE: a European collaborative study on vascular determinants of brain lesions. Study design and objectives.

Dementia is a highly prevalent disease that may have a cardiovascular component. White matter lesions and brain atrophy (brain abnormalities) are prevalent in dementia cases and might form part of the anatomical basis for the disease. We designed a multi-centre study, CASCADE (Cardiovascular Determinants of Dementia), to examine long-term (10-20 years) and short-term (5 years) cardiovascular risk factors for, and the cognitive consequence of, brain abnormalities. White matter lesions and atrophy are measured with magnetic resonance imaging. Cognitive function is measured with nine tests of memory and executive function. The studies included in CASCADE were ongoing and geographically spread throughout Europe to capture the cardiovascular risk gradient. In each study, a random sample of at least 100 subjects aged 65-75 years was selected who participated in the previous research examinations conducted by the respective centres. The objectives and design of the CASCADE project are described.

Aged↗
PubMedDate not supplied

Risk of acute hypotension following epidural analgesia during deep regional hyperthermia: a case report.

A potentially dangerous complication occurring during deep regional hyperthermia is described. A patient receiving epidural analgesics for pain caused by a large pelvic recurrent rectal tumour was treated by hyperthermia induced by electromagnetic radiation. The epidural infusion pump failed during heating and further analgesics were administered by bolus injections into the epidural space. Following the second bolus injection, a severe drop in arterial blood pressure was observed. The most likely multifactorial pathogenesis is discussed and measures to avoid such an event are recommended.

Analgesia, Epidural↗
PubMedDate not supplied

Isolated hypoxic hepatic perfusion (IHHP) using balloon catheter techniques: from laboratory to the clinic towards a percutaneous procedure.

BACKGROUND/AIMS: The success of and our extensive experience with TNF alpha-based isolated limb perfusions in patients with unresectable extremity soft tissue sarcomas made us explore the possibilities for a similar approach for the treatment of hepatic metastases. After experience with the classic surgical isolated hepatic perfusion in pigs and in patients, we concluded that the classic surgical approach was associated with serious drawbacks i.e., magnitude of the procedure with morbidity, lack of repeatability of the procedure, complexity and costs. These problems were addressed in a program aimed at developing a repeatable method of isolated perfusion of the liver with minimally invasive techniques. METHODOLOGY: We validated the methodology of isolated hypoxic hepatic perfusion using balloon catheter techniques in pigs. RESULTS: The excellent pharmacokinetic profile of the procedure, resulting in very high regional drug concentrations and negligible systemic drug concentrations, allowed us to move on to the clinic and start to study and further develop this method in a phase I-II study using the drug melphalan, in patients with irresectable hepatic metastases. CONCLUSIONS: We aim to develop step by step a fully percutaneous approach for isolated hypoxic hepatic perfusion.

Aged↗