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

ISOSPIN SYMMETRY OF T-z = +/- 3/2 -&gt; +/- 1/2 GAMOW-TELLER TRANSITIONS IN A=37 AND A=41 NUCLEI

Under the assumption of good isospin symmetry, T-z = +/- 3/2 +/- 1/2 Gamow-Teller (GT) transitions in a mass A isobar are analogous, where Tz is the z component of isospin T defined by 1/2(N-Z). We studied the T-z=+3/2 -> +1/2 GT transitions by using the Cl-37(He-3,t)(37) Ar and K-41(He-3,t)(41) Ca reactions at E-beam=140 MeV/nucleon. The GT transition strengths in Ar-37 and Ca-41 were obtained upto the excitation energy (E-x) of 14.2 MeV and 10.4 MeV with energy resolutions of 30 and 35 keV, respectively. The obtained GT strengths were compared with those of the T-z=-2/3 ->-1/2 mirror transitions, measured by the fi-decay of Ca-37 and Ti-41, respectively. It was found that the overall distributions of the mirror transitions were similarin both A=37 and A=41 systems. In A=37 the differences seen at lower excitation energies are suggested to be the effect of the tensorinteraction in the charge-exchange reaction. The differences seen at higher excitation energies are suggested to be the effect of the Coulomb interaction that can break the mirror symmetry of the strength distributions