Biomedical subjects

R Valkema

Publications and source records attributed to R Valkema.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Accuracy of exercise stress technetium 99m sestamibi SPECT imaging in the evaluation of the extent and location of coronary artery disease in patients with an earlier myocardial infarction.

BACKGROUND: This study assessed the accuracy of exercise methoxy isobutyl isonitrile (MIBI) single photon emission computed tomography (SPECT) in the evaluation of the extent of coronary artery disease (CAD) in patients with an earlier myocardial infarction. METHODS AND RESULTS: We studied 135 patients (mean age, 57+/-10 years; 115 men) at a mean of 4.1 years (median, 1 year) after myocardial infarction with symptom-limited bicycle exercise stress and rest MIBI SPECT imaging. Coronary angiography was performed within 3 months. Significant CAD was defined as a stenosis of 50% or larger in luminal diameter in 1 or more major coronary arteries. Myocardial perfusion defects (fixed, reversible, or both) were detected in 107 of the 113 patients with significant CAD and in 10 of the 22 patients without significant CAD (sensitivity, 95%; CI, 91 to 99; specificity, 55%; CI, 46 to 63, and accuracy, 88%; CI, 82 to 94). The specificity rate increased to 73% (CI, 65 to 80) by using only reversible perfusion defects as a means of predicting CAD. Reversible perfusion abnormalities were more frequent in patients with multivessel CAD than in patients with single-vessel CAD (51 of 64 [80%] vs. 27 of 49 [55%], P<.01). Myocardial perfusion abnormalities in 2 vascular regions, which is suggestive of multivessel CAD, were detected in 35 of the 64 patients with and in 9 of the 71 patients without multivessel CAD (sensitivity for detecting CAD in more than one vascular region, 55%; CI, 46 to 63, specificity, 87%; CI, 81 to 93, and accuracy, 72%; CI, 64 to 80). The sensitivity rates for the diagnosis of left anterior descending coronary artery, left circumflex, and right coronary artery based on any defect were 80%, 70%, and 63%, respectively. The corresponding specificity rates were 70%, 76%, and 73%, respectively. CONCLUSIONS: Exercise MIBI SPECT imaging is an accurate method for the diagnosis and localization of CAD in patients with an earlier myocardial infarction. The technique provides a high specificity and moderate sensitivity for the diagnosis of multivessel CAD on the basis of myocardial perfusion abnormalities in more than 1 vascular region.

Adult↗

PubMedDate not supplied

Dobutamine technetium-99m tetrofosmin SPECT imaging for the diagnosis of coronary artery disease in patients with limited exercise capacity.

BACKGROUND: Technetium-99m tetrofosmin single photon emission computed tomography (SPECT) imaging is increasingly used in conjunction with exercise and vasodilator stress test as a means of evaluating coronary artery disease (CAD). Dobutamine stress test is an alternative in patients with limited exercise capacity. This study assessed the accuracy of dobutamine-atropine stress tetrofosmin SPECT as a means of diagnosing and localizing CAD. METHODS AND RESULTS: We studied 124 patients (mean age, 57+/-12 years; 88 men) with limited exercise capacity and suspected CAD with dobutamine (as much as 40 microg/kg/min)-atropine (as much as 1 mg) Tc-99m tetrofosmin SPECT. Resting images were acquired 24 hours after the stress test. Significant CAD was defined as 50% or greater luminal diameter stenosis in 1 or more major coronary arteries. Myocardial perfusion abnormalities (fixed and/or reversible defects) were detected in 70 of 88 patients with CAD and in 10 of the 36 patients without CAD (sensitivity = 80%, CI, 72 to 87; specificity = 72%, CI, 64 to 80; accuracy = 77%, CI, 70 to 85). Sensitivity and accuracy rates were higher by using the criterion of any defect than by using the criterion of reversible defects only (80% vs 51%, P<.0001; 77% vs 60%, P<.01, respectively). The sensitivity rate was higher in patients with multivessel CAD than in patients with single-vessel CAD (88% vs 63%, P<.05). Patients with multivessel CAD had a larger stress perfusion defect score (4.5+/-3.1 vs. 2.7+/-2.5, P<.01) than patients with single-vessel CAD. CONCLUSION: Dobutamine stress Tc-99m tetrofosmin SPECT is a useful method for the diagnosis and localization of CAD in patients with limited exercise capacity. Optimal accuracy of the technique is achieved by using both fixed and reversible perfusion abnormalities for the diagnosis of CAD in patients without an earlier myocardial infarction.

Atropine↗

PubMedDate not supplied

The diagnostic value of immediate post-exercise left ventricular ejection fraction (LVEF).

The diagnostic value of immediate post-exercise left ventricular ejection fraction (LVEF) was assessed in 161 patients at rest, during maximal exercise, and immediately post-exercise by radionuclide angiography. Fifteen patients had a second examination, giving a total of 176 radionuclide examinations. Additionally, the correlation between post-exercise LVEF and physical validity was investigated. Sixty-one patients (35%) with a recent myocardial infarction (less than 4 weeks), 66 patients (37%) with an old myocardial infarction (greater than 4 weeks), and 21 patients (12%) with valvular lesions were studied. Twenty-eight patients (16%) with an abdominal aneurysm were considered as controls based on history and a normal resting and exercise electrocardiogram (ECG). LVEF and a cumulative regional wall motion (RWM) score for three regions were obtained. LVEF post-exercise was significantly increased compared to LVEF at maximal exercise in all four diagnostic groups. Absolute LVEF values were significantly dependent on the level of exercise. We conclude that immediate post-exercise LVEF should not be used for separating patients with and without coronary artery disease.

Adult↗

PubMedDate not supplied

Bone mineral density in ambulant, non-steroid treated female patients with rheumatoid arthritis.

Bone mass measurements were performed in a group of 30 ambulant, non-steroid treated female patients with rheumatoid arthritis (RA) of relatively short duration (mean 4.9 years). The bone mineral density (BMD) of the lumbar spine and femoral neck was assessed by dual-energy x-ray absorptiometry (DEXA), and related to parameters of disease activity and severity. Lumbar BMD was within the range of normal while femoral BMD was decreased compared to age-matched controls. BMD values, expressed as the percentage of age-matched healthy controls (BMD%), were positively related to the body mass index and negatively related to the number of swollen joints, the erythrocyte sedimentation rate and the platelet count. No relation was found between the lumbar and femoral bone mass on the one hand and disease duration, number of disease modifying anti-rheumatic drugs ever used, Ritchie articular index, C-reactive protein, functional ability or radiological scores on the other. It is concluded that in ambulant non-steroid treated female RA patients lumbar bone mass as measured with DEXA is within the range of normal, while femoral bone mass is slightly reduced. Both lumbar and femoral bone mass are related to the body mass index and parameters of disease activity.

Absorptiometry, Photon↗