929-63 Dobutamine Stress Cine Magnetic Resonance Imaging versus PET for Detection of Myocardial Viability

To identify viable myocardium before coronary revascularization, we prospectively submitted eleven patients (60±7 yrs; 11 M) with previous Q-wave myocardial infarction to 18FDG-Positon Emission Tomography and low-dose (5 to 10 μg/kg/min) dobutamine cine-MRI. 18FDG uptake > 60% was considered indicative of viable tissue. Ouantitation of systolic wall thickening/thinning (SW) was performed by use of a computer software allowing automatic detection of epicardial and endocardial outlines, at rest and under 5, 7.5 and 10 μg/kg/min of dobutamine. Heart slices of both 18FDG-PET scans and dobutamine cine-MRI were divided in 8 segments, matched and analyzed byobservers blinded to clinical data. Sixty-five segments were considered viable by 18FDG-PET; in this subgroup, rest SW thickening averaged 47±5% and improved by 43±8% under low-dose dobutamine. In the remaining 23 segments considered non viable by PET. rest SW thickening averaged 14±7%*(*p<0.05 vs viable segment group) and further worsened by –13±8%*during low-dose dobutamine stress (*p<0.05 versus viable segment group). Positive predictive value of low-dose dobutamine stress cine-MRI for assessment of myocardial viability was 84%. These data suggest that quantitative assessment of regional wall motion by dobutamine cine-MRI may help discriminate viable from non viable myocardium as defined by 18FDG-Positon Emission Tomography

Gated blood-pool SPECT evaluation of changes after radiofrequency catheter ablation of accessory pathways Evidence for persistent ventricular preexcitation despite successful therapy

AbstractOBJECTIVESThis study was designed to prospectively evaluate the effects of radiofrequency ablation in Wolff-Parkinson-White (WPW) syndrome by scintigraphic analysis.BACKGROUNDThe functional changes triggered by radiofrequency current ablation of atrioventricular accessory pathways are not fully known.METHODSForty-four patients with WPW syndrome were consecutively investigated before and 48 h after radiofrequency therapy. Fourteen patients had right sided atrioventricular pathways and 30 patients had left sided bypass-tracts. Planar gated imaging and gated blood pool tomography were performed in all of these patients.RESULTSA significant increase in the left ventricular ejection fraction (LVEF) was demonstrated in patients with left preexcitation (62.2 ± 7.9% before ablation against 64.4 ± 6.3% after ablation, p = 0.02) but not for those with right sided anomalous pathway. Phase analysis only gave significant differences following ablation of right sided pathways (left-to-right phase difference = 14.4 ± 13.8° before ablation versus 7.5 ± 7.2° after ablation, p < 0.05). Early abnormal ventricular contraction persisted in 12 patients with right accessory pathways and in 8 patients with left accessory pathways despite the complete disappearance of any abnormal conduction as proven electrophysiologically.CONCLUSIONSFollowing catheter ablation of atrioventricular accessory pathways: 1) an improvement of left ventricular function may be seen, particularly in patients with left sided accessory pathways, and 2) unexpected persistence of local ventricular preexcitation at the site of successful ablation may be detected

L'Apport de la tomographie d'émission monophotonique (SPECT) de perfusion cérébrale dans le diagnostic de la maladie d'Alzheimer et des autres démences dégénératives primaires

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Recommandations pour évaluer l'extension et la réponse à la thérapie des lymphomes avec la TEP/TDM au [18F]FDG

peer reviewedAbstract Mounting evidence supports the major role of [18F]FDG PET-CT in the assessment of response to chemotherapy in lymphoma. The five-point scale to grade response is becoming widely used both in practice and response-adapted trials. In 2014, a malignant lymphomas imaging working group composed of representatives from major international cooperative groups published revised guidelines concerning the role of imaging in the staging and response assessment of lymphoma. This paper summarizes the main recommendations to facilitate their clinical routine applications

Myocardial Perfusion Imaging With 99m Tc Tetrofosmin Comparison to 201 Tl Imaging and Coronary Angiography in a Phase III Multicenter Trial

Background Our objective was to compare the sensitivity and specificity of tetrofosmin, a new 99m Tc-labeled myocardial perfusion imaging agent for the detection of myocardial perfusion abnormalities, with those of 201 Tl and coronary angiography. Our hypothesis was that same-day stress/rest tetrofosmin imaging could provide data comparable to those of 201 Tl imaging. Myocardial perfusion imaging plays an important role for the evaluation of coronary artery disease. Newer 99m Tc-labeled agents offer several advantages over 201 Tl, the conventional myocardial perfusion imaging agent. Tetrofosmin is a new 99m Tc-labeled agent with promising results in preliminary studies. Methods and Results Two hundred fifty-two patients with suspected coronary artery disease were enrolled in 10 centers in the United States and Europe. All patients underwent exercise and rest myocardial perfusion imaging with 99m Tc-tetrofosmin using two separate injections of the radiotracer 4 hours apart on the same day. Planar images were obtained in three standard views 15 to 60 minutes after radiotracer injection. Patients also underwent standard exercise and redistribution planar 201 Tl imaging within 2 weeks of tetrofosmin imaging. In addition, 58 healthy subjects with low likelihood of coronary artery disease underwent exercise and rest tetrofosmin imaging. Coronary angiograms were available in 181 patients with suspected coronary artery disease. All radionuclide images were processed in the central core laboratory and interpreted blindly by a panel of four experienced readers. 201 Tl images and tetrofosmin images were read separately. Discrepancies were resolved by consensus. The workload, peak heart rate, and double products were comparable during exercise for both imaging agents. Technically acceptable paired 201 Tl and tetrofosmin images were available in 224 of 252 patients. Tetrofosmin images were generally of good quality, with low extracardiac activity, and easy to interpret. Patients were categorized as showing normal, ischemia, infarction, or mixture with each imaging modality. Precise concordance for each of these categories was 59.4% (κ=0.44; 95% CI, 0.35 to 0.53). When patients were categorized as normal or abnormal, the concordance was 80.4% (κ=0.55; 95% CI, 0.43 to 0.67). When each of five anatomic territories (septal, anterior, inferior, lateral, and apical) was categorized as normal versus abnormal, the concordance varied from 81% to 90%. When similar comparison was made for the specific category of abnormality, the concordance was 64% to 84%. When coronary angiography was used as the criterion, the sensitivity and positive and negative predictive accuracy of tetrofosmin and 201 Tl were comparable. The normalcy rate of tetrofosmin images in the healthy subjects with low likelihood of coronary artery disease was 97%. Conclusions 99m Tc tetrofosmin is a new myocardial imaging agent with favorable imaging characteristics with results comparable to those of 201 Tl. </jats:p

The long and the short of it: spatial statistics at fixation vary with saccade amplitude and task

AbstractWe recorded over 90,000 saccades while observers viewed a diverse collection of natural images and measured low level visual features at fixation. The features that discriminated between where observers fixated and where they did not varied considerably with task, and the length of the preceding saccade. Short saccades (<8°) are image feature dependent, long are less so. For free viewing, short saccades target high frequency information, long saccades are scale-invariant. When searching for luminance targets, saccades of all lengths are scale-invariant. We argue that models of saccade behaviour must account not only for task but also for saccade length and that long and short saccades are targeted differently