1.
Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation/perfusion SPET-CT images: initial experiences.
Suga, K, Yasuhiko, K, Zaki, M, Yamashita, T, Seto, A, Matsumoto, T, Matsunaga, N
European journal of nuclear medicine and molecular imaging. 2004;(2):240-9
Abstract
In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (n = 15); in 34 of these patients, it was performed in combination with gated technetium-99m Technegas SPET. Projection data were acquired using 60 stops over 120 degrees for each detector. Gated end-inspiration and ungated images were reconstructed from 1/8 data centered at peak inspiration for each regular respiratory cycle and full respiratory cycle data, respectively. Gated images were registered with tidal inspiration CT images using automated three-dimensional (3D) registration software. Registration mismatch was assessed by measuring 3D distance of the centroid of the nine selected round perfusion-defective nodules. Gated SPET images were completed within 29 min, and increased the number of visible ventilation and perfusion defects by 9.7% and 17.2%, respectively, as compared with ungated images; furthermore, lesion-to-normal lung contrast was significantly higher on gated SPET images. In the nine round perfusion-defective nodules, gated images yielded a significantly better SPET-CT match compared with ungated images (4.9 +/- 3.1 mm vs 19.0 +/- 9.1 mm, P<0.001). The co-registered SPET-CT images allowed accurate perception of the location and extent of each ventilation/perfusion defect on the underlying CT anatomy, and characterised the pathophysiology of the various diseases. By reducing respiratory motion effects and enhancing perfusion/ventilation defect clarity, gated SPET can provide reliable co-registered images with CT images to accurately characterise regional functional impairment in various lung diseases.
2.
Low-dose dobutamine stress 99mTc tetrofosmin quantitative gated SPECT performed during the acute phase of myocardial infarction predicts subsequent myocardial viability and detects stunned myocardium.
Kasama, S, Toyama, T, Kumakura, H, Takayama, Y, Ichikawa, S, Suzuki, T, Kurabayashi, M
Nuclear medicine communications. 2003;(2):167-74
Abstract
This study evaluated the ability of low-dose dobutamine stress 99mTc tetrofosmin (DSTF) quantitative gated single photon emission computed tomography (QGS) performed during the acute phase of myocardial infarction to predict subsequent myocardial viability and detect stunned myocardium. Twenty-four patients suffering their first acute myocardial infarction (AMI) underwent coronary angioplasty after coronary angiography (CAG) immediately following admission. Follow-up CAG and left ventriculography (LVG) were performed 10 days and 6 months later. All patients underwent DSTF QGS to measure left ventricular ejection fraction (LVEF) at rest and during dobutamine infusion (10 microg.kg(-1).min(-1)) 14 days after angioplasty. No patient suffered coronary restenosis. After 6 months, the LVEF measured by LVG improved >5% in 12 patients (group A), and did not improve in the remaining 12 patients (group B). The culprit coronary artery, the peak serum creatine phosphokinase concentration, the recanalization time, and the LVEF during the acute phase were similar in the two groups. However, the increase in the LVEF was greater in group A than in group B during dobutamine infusion (deltaLVEF) as measured by DSTF QGS (11.2+/-3.8% vs 2.9+/-4.7%, P <0.001). If a cut-off value of 6.5% for the deltaLVEF was used to predict the improvement in LVEF during the chronic phase, then the sensitivity of this test was 83.3% and its specificity was 83.3%. It is concluded that DSTF QGS during AMI can be used to predict myocardial viability and detect stunned myocardium.