Quantitative detection of myocardial ischaemia by stress echocardiography; a comparison with SPECT

<p>Abstract</p> <p>Aims</p> <p>Real-time perfusion (RTP) adenosine stress echocardiography (ASE) can be used to visually evaluate myocardial ischaemia. The RTP power modulation technique angio-mode (AM), provides images for off-line perfusion quantification using Qontrast^®software, generating values of peak signal intensity (A), myocardial blood flow velocity (β) and myocardial blood flow (Axβ). By comparing rest and stress values, their respective reserve values (A-r, β-r, Axβ-r) are generated. We evaluated myocardial ischaemia by RTP-ASE Qontrast^®quantification, compared to visual perfusion evaluation with ^99mTc-tetrofosmin single-photon emission computed tomography (SPECT).</p> <p>Methods and Results</p> <p>Patients admitted to SPECT underwent RTP-ASE (SONOS 5500) using AM during Sonovue^®infusion, before and throughout adenosine stress, also used for SPECT. Visual myocardial perfusion and wall motion analysis, and Qontrast^®quantification, were blindly compared to one another and to SPECT, at different time points off-line.</p> <p>We analyzed 201 coronary territories (left anterior descendent [LAD], left circumflex [LCx] and right coronary [RCA] artery territories) in 67 patients. SPECT showed ischaemia in 18 patients and 19 territories. Receiver operator characteristics and kappa values showed significant agreement with SPECT only for β-r and Axβ-r in all segments: area under the curve 0.678 and 0.665; P < 0.001 and < 0.01, respectively. The closest agreements were seen in the LAD territory: kappa 0.442 for both β-r and Axβ-r; P < 0.01. Visual evaluation of ischaemia showed good agreement with SPECT: accuracy 93%; kappa 0.67; P < 0.001; without non-interpretable territories.</p> <p>Conclusion</p> <p>In this agreement study with SPECT, RTP-ASE Qontrast^®quantification of myocardial ischaemia was less accurate and less feasible than visual evaluation and needs further development to be clinically useful.</p

Versatile production method of thin targets supported by PVA

Thin self-supporting targets are indispensable in high energy-resolution studies using a magnetic spectrometer. However, nuclear targets of alkaline and alkaline-earth metal or halogen isotopes are not easily available. In order to produce thin target foils of these elements for the use in charge-exchange reactions, we take advantage of the fact that the stable isotopes of these elements have relatively small negative Q values, while 1, C and 160 have large negative Q values. Therefore, even if organic compounds containing carbon and oxygen are used as supporting material, clean spectra on alkaline and alkaline-earth metal or halogen targets can be obtained up to the excitation energies of Q-value differences. A technique to produce thin foils of the chemical compounds Na2CO3, K2CO3, Ca2CO3 and CaCl2, was developed using polyvinylalcohol as supporting material. Foils with a total thickness of 1-2 mg/cm(2) were produced and used as targets in a (He-3, t) reaction study at an incident energy of 420 MeV. Owing to the small contributions of energy-loss differences of beam and reaction products in such thin targets, a very good resolution of DeltaE/E = 7 x 10(-5) was achieved in combination with a high-resolution magnetic spectrometer. (C) 2003 Elsevier B.V. All rights reserved

Gamow-Teller transitions from 58^{58}Ni to discrete states of 58^{58}Cu

Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states of T = 1, T-z = +/-1 nuclei to the common excited states of the T-z = 0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow-Teller (GT) transitions obtained from a (p, n)-type charge-exchange reaction on a target nucleus with T-z = 1 with those from the beta-decay of the T-z = -1 nucleus. The A = 58 system is the heaviest for which such a comparison is possible. As a part of the symmetry study, we measured the GT transitions from Ni-58 (T-z = 1) to Cu-58 (T-z = 0) by using the zero-degree (He-3,t) reaction at 150 MeV/nucleon. With the achieved resolution of 50 keV, many hitherto unresolved GT states have been identified. The GT transition strengths were obtained for states up to 8 MeV excitation, i.e., Dear to the Q window limitation (Q(EC) = 9.37 MeV) of the beta-decay from Zn-58 (T-z = -1) to Cu-58. The strength distribution is compared with that from shell-model calculations

Gamow-Teller transitions from Ni-58 to discrete states of Cu-51 - The study of isospin symmetry in atomic nuclei

Under the assumption that isospin is a good quantum number, symmetry is expected for the transitions from the ground states of T = 1, T-z = +/-1 nuclei to the common excited states of the T-z = 0 nucleus situated between the two nuclei. The symmetry can be studied by comparing the strengths of Gamow-Teller (GT) transitions obtained from a (p, n)-type charge-exchange reaction on a target nucleus with T-z = 1 with those from the beta-decay of the T-z = -1 nucleus. The A = 58 system is the heaviest for which such a comparison is possible. As a part of the symmetry study, we measured the GT transitions from Ni-58 (T-z = 1) to Cu-58 (T-z = 0) by using the zero-degree (He-3,t) reaction at 150 MeV/nucleon. With the achieved resolution of 50 keV, many hitherto unresolved GT states have been identified. The GT transition strengths were obtained for states up to 8 MeV excitation, i.e., Dear to the Q window limitation (Q(EC) = 9.37 MeV) of the beta-decay from Zn-58 (T-z = -1) to Cu-58. The strength distribution is compared with that from shell-model calculations