Search

OBJECTIVES: The aim of this study was to investigate the correlation between myocardial ischemia detected by myocardial perfusion imaging (MPI) with single-photon emission computed tomography with intracoronary pressure-derived fractional flow reserve (FFR) in patients with multivessel coronary disease at angiography. BACKGROUND: Myocardial perfusion imaging can underestimate the number of ischemic territories in patients with multivessel disease. However, there are limited data comparing MPI and FFR, a highly accurate functional index of myocardial ischemia, in multivessel coronary disease. METHODS: Sixty-seven patients (201 vascular territories) with angiographic 2- or 3-vessel coronary disease were prospectively scheduled to undergo within 2 weeks MPI (rest/stress adenosine) and FFR in each vessel. RESULTS: In 42% of patients, MPI and FFR detected identical ischemic territories (mean number of territories 0.9 +/- 0.8 for both; p = 1.00). In the remaining 36% MPI underestimated (mean number of territories; MPI: 0.46 +/- 0.6, FFR: 2.0 +/- 0.6; p

Peak exercise oxygen uptake (peakVO2) is a widely used prognosticator. Novel spirometric parameters, less affected by submaximal performance, such as the rate of increase of minute ventilation per unit decrease of carbon dioxide production (VE/VCO2 slope) and the oxygen uptake efficiency slope (OUES) have recently been introduced.To evaluate the discriminative value of OUES, as compared to VE/VCO2 slope in patients with coronary artery disease (CAD) and intermediate peakVO2 values.Bicycle spiroergometry was applied in 214 patients with CAD (age 67+/-8 years, 85% men). OUES was strongly related to peakVO2 (r=0.79). New York Heart Association (NYHA) class, 6-min walking distance, N-terminal pro-brain natriuretic peptide (NT-proBNP), inflammatory markers, left ventricular (LV) volumes and ejection fraction were evaluated. NT-proBNP levels predicted independently VE/VCO2-slope and OUES. Patients with intermediate peakVO2 (12-18 ml/kg per min) and increased VE/VCO2-slope (or = 35) had higher NYHA class, lower walking distance, higher NT-proBNP levels and higher LV volumes as compared to patients with a similar peakVO2 but lower VE/VCO2-slope. Similar findings were found for patients with intermediate peakVO2 and high OUES/kg (median value15.3).In CAD patients, OUES was strongly correlated with peakVO2. Both VE/VCO2 slope and OUES were independently associated with NT-proBNP levels. Both VE/VCO2 slope and OUES/kg were able to identify a subgroup of patients with an intermediate peakVO2 that was characterized by advanced remodelling and a higher degree of neurohumoral activation.

Coronary artery disease is a major cause of morbidity and mortality in the elderly population. As a result of ageing of the population and better medical, interventional and surgical treatment of patients with coronary artery disease, more and more elderly patients are referred to the cardiology department for diagnostic work-up. Stress testing, in combination with myocardial perfusion imaging, is routinely used in elderly patients, a population in which the diagnosis of significant coronary artery disease is often challenging because of atypical symptomatology. Since the introduction of technetium-99m ligands for myocardial perfusion imaging, it is possible to perform electrocardiogram-gated perfusion imaging. This not only improves the specificity of the test for coronary artery disease detection, but also enables the simultaneous assessment of left ventricular functional parameters. This article briefly overviews the possible stress modalities, diagnostic accuracy and prognostic value of myocardial perfusion imaging in elderly patients.

Although myocardial gated single photon emission computed tomography (SPECT) is routinely used for functional measurements in patients with coronary artery disease (CAD) and heart failure, day-to-day variability of left ventricular ejection fraction (LVEF), left ventricular (LV) volumes, and global perfusion scoring has not yet been investigated.In 20 consecutive patients with CAD and an LVEF lower than 40% who routinely underwent a resting tetrofosmin gated SPECT study, we performed an additional gated SPECT study at rest 1 to 5 days later under the same circumstances. LV volumes and LVEF were calculated from the gated SPECT data by commercially available software (QGS). Myocardial perfusion was scored visually by use of a 20-segment, 5-point scoring method. For global LV function and perfusion, agreement between data was investigated by use of Bland-Altman plotting. The 95% limits of agreement found by Bland-Altman analysis were -0.9% +/- 6.0% for LVEF, 3 +/- 20 mL for LV end-diastolic volume, and 4 +/- 20 mL for LV end-systolic volume.In CAD patients with an LVEF lower than 40%, day-to-day variability of measurements of global myocardial function and perfusion is quite similar to interobserver and intraobserver variability. Day-to-day variability of global LV functional parameters obtained by gated cardiac SPECT is fairly small, which indicates that myocardial gated SPECT can be used in daily clinical practice to determine changes in global LV function and perfusion over time in patients with diminished LV function.

The non-invasive assessment of postoperative spinal infections can pose a substantial diagnostic challenge, especially in the presence of orthopaedic devices. Whereas white blood cell scanning is of limited use in the spine, the low normal bone marrow uptake of technetium-99m ciprofloxacin combined with its claimed bacterial specificity makes it theoretically an ideal candidate for the evaluation of postoperative spinal infections. This study aimed to evaluate 99mTc-ciprofloxacin planar and single-photon emission tomography (SPET) imaging in relation to microbiological and clinical diagnosis in the postoperative spine. Planar imaging was performed at 1, 3 and 24 h and SPET was performed at 3 h post injection of 370 MBq 99mTc-ciprofloxacin. Images were scored by two independent certified nuclear medicine physicians, blinded to the final diagnosis. Within the 48 patients, there were 13 deep infections. Sensitivity, specificity and accuracy at visual scoring were respectively 54%, 71% and 67% (1 h), 62%, 77% and 73% (3 h), 42%, 91% and 77% (24 h) for planar imaging and 100%, 74% and 81% for SPET. When recently operated patients (

Background: Patients with coronary artery disease (CAD), a QRS duration ≥120 ms and left ventricular ejection fraction (LVEF) ≤30% are potential candidates for cardiac resynchronization therapy (CRT). Our aim was to investigate the relationship between QRS duration, left ventricular volumes and prevalence of nonviable tissue in this patient population. Methods: We studied 132 patients (118 men, age 68±5 years) with CAD and LVEF ≤30% (mean LVEF 24±6%). LV volumes and myocardial viability were determined by gated myocardial perfusion imaging. Results: A QRS duration ≥120 ms was present in 91 patients (69%). Although there were no differences in LVEF, patients with longer QRS durations had significant larger end-diastolic and end-systolic volumes (p

Background. Various algorithms have been developed to compute right ventricular (RV) and left ventricular (LV) end-diastolic volumes, end-systolic volumes, and ejection fractions (EF) from tomographic radionuclide ventriculography (TRV). The aims of this investigation were to establish sex-specific normal limits, to determine whether different algorithms produce the same normal values, and to compare TRV normal limits vs for magnetic resonance imaging values in the literature.Methods. Fifty-one healthy volunteers (29 men, 22 women) were studied prospectively. All subjects had normal electrocardiograms and echocardiographic examinations, and underwent both planar radionuclide ventriculography and TRV. Four algorithms were used to process TRV data. Results. Normal limits for most functional parameters differed significantly from one algorithm to another. Volumes were greater in men, but no statistically significant differences were found between men and women for LV EF or RV EF values for any method. Normal LV and RV EF and volumes were largely consistent with the literature for cardiac magnetic resonance imaging.Conclusions. Ventricular measurements differ significantly among TRV algorithms. Therefore, it is important to apply sex-specific normal limits that are specific to a given TRV algorithm in interpreting LV and RV EF and volume measurements for each patient.

Several studies have shown that longitudinal systolic function and left ventricular filling pressures, as assessed with tissue Doppler imaging, predict exercise capacity.The aim of this study was to evaluate whether natriuretic peptides and inflammatory parameters can independently predict maximum oxygen uptake at peak exercise (VO2max) on top of tissue Doppler imaging-derived markers.We evaluated 142 patients (age 70 +/- 6 years, 77% men) with known or suspected coronary artery disease and a preserved left ventricular ejection fraction (or = 50%). All patients underwent bicycle spiroergometry, and N-terminal pro-B-type natriuretic peptide levels were determined. Cytokines (IL-6 and soluble tumor necrosis factor receptors 1 and 2) and high-sensitivity C-reactive protein were measured as inflammatory markers. Tissue Doppler imaging was applied to evaluate peak long axis systolic velocities (Sm) and early mitral annulus velocities (E'). Ratio of early transmitral flow (E) to E' was assessed as marker of left ventricular filling. Analysis of variance, comparing VO2max quartiles, was used to determine univariate predictors and linear regression to determine multivariate VO2max predictors.Average VO2max was 18.5 +/- 5.7 mL/kg per minute (range 6-36.6). Compared with the highest quartile, patients with low VO2max were more frequently women (P.0001). N-terminal pro-B-type natriuretic peptide and cytokine levels were significantly higher in the lower VO2max categories. Longitudinal myocardial velocities increased, and E/E' decreased along with increasing VO2max. In multivariate linear regression analysis, VO2max was independently predicted by sex, glucose, Sm, E/E', and cytokine levels.Maximum oxygen uptake at peak exercise in patients with known or suspected coronary artery disease and preserved systolic function was independently predicted by inflammatory makers on top of tissue Doppler-derived systolic and diastolic function.

Background. Perfusion and functional data obtained during gated single photon emission computed tomography (SPECT) have proven prognostic value in the middle-aged patient population. The aim of this study was to investigate whether perfusion and functional cardiac gated SPECT data have prognostic value in patients aged 75 years or older. Methods and Results. We studied clinical and gated SPECT predictors of cardiac and all-cause death in 294 patients aged 75 years or older with known or suspected coronary artery disease who were referred for tetrofosmin cardiac gated SPECT imaging. Summed perfusion scores were calculated in a 17-segment model by use of commercially available software (4D-MSPECT). Left ventricular functional data were calculated by use of QGS gated SPECT software. The median age of the study population was 78 years (range, 75-91 years). There were 160 men (54%) and 134 women (46%). During a median follow-up of 25.9 months (range, 1.8-36 months), 47 patients (16%) died (27 cardiac deaths). Ina multivariate Cox proportional hazards regression analysis, the summed rest score (chi(2) gain = 8.0, P = .009), transient ischemic dilatation index (chi(2) gain = 6.3, P = .012), and resting left ventricular ejection fraction (chi(2) gain = 7.0, P = .030) were independent predictors of all-cause death. The summed rest score (chi(2) gain = 8.2, P = .004) and resting end-systolic volume (chi(2) gain = 13.7, P = .005) were independent predictors of cardiac death. Conclusions. This study showed that gated SPECT left ventricular functional data assessed during myocardial gated SPECT provide independent and incremental information above clinical and perfusion SPECT data for the prediction of cardiac and all-cause death in patients aged 75 years or older referred for myocardial SPECT imaging.

Previous studies have demonstrated reduced exercise capacity in patients with diabetes mellitus. This study evaluated the relationship between fasting blood glucose (FBG) levels and exercise capacity in patients with coronary artery disease (CAD).We evaluated 986 consecutive patients with CAD referred for bicycle spiroergometry combined with gated myocardial perfusion imaging. Maximum oxygen consumption (VO2max) and maximal watts were measured. Patients were divided into 4 FBG categories:100 mg/dL (n = 611), 100 to 109 mg/dL (n = 144), 110 to 125 mg/dL (n = 102), andor = 126 mg/dL (n = 129). Differences in clinical characteristics, exercise hemodynamics, perfusion imaging, and univariate as well as multivariate predictors of exercise capacity were determined.Maximal watts and VO2max were significantly lower (P.0001) in patients with higher FBG levels and were related to FBG values in univariate and multivariate analyses. Left ventricular volumes and ejection fractions did not differ between the FBG categories. Myocardial perfusion imaging showed a comparable degree of ischemia in the 4 FBG groups. However, patients with higher FBG levels had higher heart rate and blood pressure values at rest resulting in a higher rate-pressure product (values in the 4 FBG groups 8299 +/- 2051, 8733 +/- 2008, 9558 +/- 2583, and 9588 +/- 2468 beat/min x mm Hg, P.0001), suggesting increased myocardial oxygen consumption per unit time at rest.Exercise capacity in patients with CAD is related to FBG levels. Patients with impaired fasting glucose or an FBG levelor = 126 mg/dL reached lower peak watts and lower VO2max values. This could be attributed to a higher myocardial oxygen consumption per unit time at rest and the inability to adapt their coronary flow adequately to higher metabolic demands during maximal exercise.

Background and aim Left and right ventricular ejection fractions (LVEF and RVEF) and end-diastolic and end-systolic volumes (LVEDV, RVEDV, LVESV and RVESV) can be calculated from tomographic radionuclide ventriculography (TRV). The aim of this study was to validate and compare these parameters obtained using four different TRV software programs (QBS, QUBE, 4D-MSPECT and BIP-SPECT). Methods LVEF obtained from planar radionuclide ventriculography (PRV) was compared with LVEF obtained from TRV using the four different software programs in 166 patients. Furthermore, ventricular volumes obtained using TRV (QBS, QUBE and 4D-MSPECT) were compared with those obtained using BIP-SPECT, the latter being the only method with the validation of ventricular volumes in the literature. Results The correlation of LVEF between PRV and TRV was good for all methods: 0.81 for QBS, 0.79 for QUBE, 0.71 for 4D-MSPECT and 0.79 for BID-SPECT. The mean differences standard deviation (SD) were 3.16 +/- 9.88, 10.72 +/- 10.92, 3.43 +/- 11.79 and 2.91 +/- 10.39, respectively. The correlation of RVEF between BP-SPECT and QUBE and QBS was poor: 0.33 and 0.38, respectively. LV volumes calculated using QBS, QUBE and 4D-MSPECT correlated well with those obtained using BP-SPECT (0.98, 0.90 and 0.98, respectively), with mean differences +/- SD of 7.31 +/- 42.94, - 22.09 +/- 36.07 and - 40.55 +/- 39.36, respectively. RV volumes showed poorer correlation between QBS and BP-SPECT and between QUBE and BP-SPECT (0.82 and 0.57, respectively). Conclusion LVEF calculated using TRV correlates well with that calculated using PRV, but is not interchangeable with the value obtained using PRV. Volume calculations (for left and right ventricle) and RVEF require further validation before they can be used in clinical practice.

Background Automatic and semi-automatic algorithms to calculate ejection fraction (EF) from planar radionuclide ventriculography (PRV) have been used for many years in nuclear medicine. Validation of these algorithms is scarce and often performed on outdated versions of the software. Nevertheless, clinical trials where PRV is being used as the 'gold standard' for EF are numerous. Because of the importance attributed to the EF calculated by these programs, the accuracy of the resulting EF was assessed with a dynamic left ventricular physical phantom. Methods A dynamic left ventricular phantom was used to simulate 21 combinations of various ejection fractions (7-66%) and end diastolic volumes (27-290 ml). For each combination, a planar radionuclide ventriculograph was acquired, converted to an interfile format and transferred into processing stations with 10 different contemporaneously available commercial algorithms. The gold standard was the 'real' EF of the phantom, derived from the exact volume of the ventricle in end diastolic and end systolic position. Correlation and Bland-Altman analysis was performed between the real EF and the calculated EF. Results The correlation for all data was excellent (r=0.98), the mean difference was very acceptable (0.98%). Nevertheless, Bland-Altman analysis showed a significant trend in the difference between real and calculated EF, with a growing underestimation for higher ranges of EF, due to an overestimation of background in larger volumes compared to smaller ones. Conclusion The determination of EF from PRV, calculated with commercially available algorithms, correlates closely to the real EF of a dynamic left ventricular phantom. This phantom can be used in the development and validation of algorithms for PRV studies, in software audits and in quality assurance procedures.

Various automatic algorithms are now being developed to calculate left ventricular (LV) and right ventricular (RV) ejection fraction from tomographic radionuclide ventriculography. We tested the performance of 4 of these algorithms in estimating LV and RV volume and ejection fraction using a dynamic 4-chamber cardiac phantom.We developed a realistic physical, dynamic 4-chamber cardiac phantom and acquired 25 tomographic radionuclide ventriculography images within a wide range of end-diastolic volumes, end-systolic volumes, and stroke volumes. We assessed the ability of 4 algorithms (QBS, QUBE, 4D-MSPECT, and BP-SPECT) to calculate LV and RV volume and ejection fraction.For the left ventricle, the correlations between reference and estimated volumes (0.93, 0.93, 0.96, and 0.93 for QBS, QUBE, 4D-MSPECT, and BP-SPECT, respectively; all with P0.001) and ejection fractions (0.90, 0.93, 0.88, and 0.92, respectively; all with P0.001) were good, although all algorithms underestimated the volumes (mean difference [+/-2 SDs] from Bland-Altman analysis: -39.83 +/- 43.12 mL, -33.39 +/- 38.12 mL, -33.29 +/- 40.70 mL, and -16.61 +/- 39.64 mL, respectively). The underestimation by QBS, QUBE, and 4D-MSPECT was greater for higher volumes. QBS, QUBE, and BP-SPECT could also be tested for the right ventricle. Correlations were good for the volumes (0.93, 0.95, and 0.97 for QBS, QUBE, and BP-SPECT, respectively; all with P0.001). In terms of absolute volume estimation, the mean differences (+/-2 SDs) from Bland-Altman analysis were -41.28 +/- 43.66 mL, 11.13 +/- 49.26 mL, and -13.11 +/- 28.20 mL, respectively. Calculation of RV ejection fraction correlated well with true values (0.84, 0.92, and 0.94, respectively; all with P0.001), although an overestimation was seen for higher ejection fractions.Calculation of LV and RV ejection fraction based on tomographic radionuclide ventriculography was accurate for all tested algorithms. All algorithms underestimated LV volume; estimation of RV volume seemed more difficult, with different results for each algorithm. The more irregular shape and inclusion of a relatively hypokinetic RV outflow tract in the right ventricle seemed to cause the greater difficulty with delineation of the right ventricle, compared with the left ventricle.

Publisher Summary Over the past few years, the finding of increased 2-Fluoro-2-deoxy-glucose (FDG) accumulation by inflammatory and infectious cells has resulted in a number of promising reports on the potential of FDG positron emission tomography (PET) imaging in different types of infections and inflammations. This chapter discusses the results deriving from these studies. Promising results have been obtained with FDG-PET in the field of clinical infectious diseases. Available studies suggest that the specificity of FDG-PET will be limited by the fact that FDG accumulates in sterile inflammatory lesions and tumors. Thus, depending on the clinical setting, the problem of specificity may theoretically limit the use of FDG-PET in infectious diseases. However, in most patients, a thorough medical history makes the presence of tumour unlikely, and sterile inflammations such as chronic polyarthritis, vasculitis, and tumors often appear at sites or show distribution patterns that are suggestive of these diseases.

Dose-effect calculations used in the planning of modern radiotherapy (RT) involving normal lung or cardiac tissue rely on structural imaging techniques, such as CT, as the basis for measuring and predicting dose-response. However, more accurate methods for predicting dose-response may result if information on the locoregional functional status of the irradiated organ(s) is included in the computational model. For RT cases that involve delivering dose to the lung and heart, this may be achieved by the assessment of tomographic scintigraphies of lung perfusion (Q) and ventilation (V) and scintigraphic imaging of myocardial perfusion and function, respectively.

We have developed a biventricular dynamic physical cardiac phantom to test gated blood-pool (GBP) SPECT image-processing algorithms. Such phantoms provide absolute values against which to assess accuracy of both right and left computed ventricular volume and ejection fraction (EF) measurements.Two silicon-rubber chambers driven by 2 piston pumps simulated crescent-shaped right ventricles wrapped partway around ellopsoid left ventricles. Twenty experiments were performed at Ghent University, for which right and left ventricular true volume and EF ranges were 65-275 mL and 55-165 mL and 7%-49% and 12%-69%, respectively. Resulting 64 x 64 simulated GBP SPECT images acquired at 16 frames per R-R interval were sent to Columbia University, where 2 observers analyzed images independently of each other, without knowledge of true values. Algorithms automatically segmented right ventricular activity volumetrically from left ventricular activity. Automated valve planes, midventricular planes, and segmentation regions were presented to observers, who accepted these choices or modified them as necessary. One observer repeated measurements1 mo later without reference to previous determinations.Linear correlation coefficients (r) of the mean of the 3 GBP SPECT observations versus true values for right and left ventricles were 0.80 and 0.94 for EF and 0.94 and 0.95 for volumes, respectively. Correlations for right and left ventricles were 0.97 and 0.97 for EF and 0.96 and 0.89 for volumes, respectively, for interobserver agreement and 0.97 and 0.98 for EF and 0.96 and 0.90 for volumes, respectively, for intraobserver agreement. No trends were detected, though volumes and right ventricular EFs were significantly higher than true values.Overall, GBP SPECT measurements correlated strongly with true values. The phantom evaluated shows considerable promise for helping to guide algorithm developments for improved GBP SPECT accuracy.

A 50-year-old man underwent both Tc-99m HMPAO mixed leukocyte scintigraphy and scintigraphy with Tc-99m-labeled monoclonal antibody fragments (via LeukoScan) as part of an ongoing study protocol comparing the accuracy of both imaging techniques for the detection of brain abscess. Although the images obtained of the brain showed no abnormality on either scans, delayed whole-body images on Tc-99m HMPAO mixed leukocyte scintigraphy, acquired 24 hours after injection, showed several areas of pathologic uptake in the lungs that were not visible on the 24-hour LeukoScan images. A subsequent computed tomographic scan suggested the presence of several granulomas resulting from an aspergillus infection. Diagnosis was confirmed by growing Aspergillus fumigatus on sputum cultures. The authors hypothesize that discordant findings between the two scintigraphic studies may be attributed to the chronic character of aspergillotic granulomas, with predominant infiltration of lymphocytes, which are only present in radiolabeled form in Tc-99m HMPAO mixed leukocytes.

Coronary artery disease (CAD) is the leading cause of mortality in the Western world. Multiple parameters have been investigated to predict prognosis in CAD patients. The prognostic value of the left ventricular ejection fraction (LVEF) in patients with CAD is well established. More recently, left ventricular (LV) volumes have also shown prognostic value. Due to the favourable imaging characteristics of technetium-99m (high count density), the development of (99m)Tc-labelled myocardial perfusion tracers has made it possible to perform an electrocardiogram-gated acquisition during routine myocardial perfusion imaging. This enables assessment of LVEF and LV volumes during myocardial perfusion scintigraphy. This review considers the possible prognostic abilities of LV volume assessment by gated cardiac SPET.

Tumour angiogenesis is essential for growth, invasion and metastasis. Retrospective studies suggest that it is an independent prognostic factor that merits prospective validation. Furthermore, as tumour blood vessels show many differences from normal vessels and are not genetically unstable, they form a key area for therapy development. However, as anti-angiogenic therapy is primarily cytostatic and not cytotoxic, novel tailor-made specific end-points for treatment monitoring are required. In this regard, suitable molecular parameters for imaging tumour angiogenesis by means of nuclear medicine are being explored. Here we review current knowledge on the multiple pathways controlling tumour angiogenesis and try to assess which are the most clinically relevant for nuclear medicine imaging. Parameters that may influence the imaging potential of radiopharmaceuticals for angiogenesis imaging such as molecular weight and structure, their targeted location within the tumour and their usefulness in terms of specificity and constancy of the targeted molecular pathway are discussed.

In normal subjects, exercise capacity is related to diastolic filling.(1) However, in patients with previous myocardial infarction, the association between exercise capacity and diastolic filling is less clear(2,3) and might be influenced by other determinants, such as infarct size and left ventricular ejection fraction (LVEF). The present study compares exercise capacity in remote myocardial infarction, between patients with normal versus abnormal LV filling patterns, stratified for infarct size and LVEF. Transmitral inflow deceleration time (DT) of the early diastolic peak velocity and color M-mode derived flow propagation velocity (Vp) of the left ventricle were used to classify LV filling patterns.(4).

A stereotactic, normal perfusion database is imperative for optimal clinical brain single-photon emission tomography (SPET). However, interdepartmental use of normal data necessitates accurate transferability of these data sets. The aim of this study was to investigate transfer of three normal perfusion databases obtained in the same large population of healthy volunteers who underwent sequential scanning using multihead gamma cameras with different resolution. Eighty-nine healthy adults (46 females, 43 males; aged 20-81 years) were thoroughly screened by history, biochemistry, physical and full neurological examination, neuropsychological testing and magnetic resonance imaging. After injection of 925 MBq technetium-99m labelled ethyl cysteinate dimer (ECD) under standard conditions, 101 scans were acquired from all subjects (12 repeat studies) on a triple-head Toshiba GCA-9300A (measured average FWHM 8.1 mm). Ninety-one sequential scans were performed on a dual-head Elscint Helix camera (FWHM 9.6 mm) and 22 subjects also underwent imaging on a triple-head Prism 3000 (FWHM 9.6 mm). Images were transferred to the same processing platform and reconstructed by filtered back-projection with the same Butterworth filter (order 8, cut-off 0.9 cycles/cm) and uniform Sorensen attenuation correction (mu = 0.09). After automated rigid intrasubject registration, all subjects were automatically reoriented to a stereotactic template by a nine-parameter affine transformation. The databases were analysed using 35 predefined volumes of interest (VOIs) with normalisation on total VOI counts. For comparison, the high-resolution data were smoothed with a 3D Gaussian kernel to achieve more similar spatial resolution. Hoffman phantom measurements were conducted on all cameras. Partial volume effects after smoothing varied between -6.5% and 10%, depending on VOI size. Between-camera reproducibility was 2.5% and 2.7% for the Toshiba camera versus the Helix and the Prism database, respectively. The highest reduction in between-camera variability was achieved by resolution adjustment in combination with linear washout correction and a Hoffman phantom-based correction. In conclusion, transfer of normal perfusion data between multihead gamma cameras can be accurately achieved, thereby enabling widespread interdepartmental use, which is likely to have a positive impact on the diagnostic capabilities of clinical brain perfusion SPET.

Olivier De Winter† & Pieter De Bondt2 †Author for correspondence; Ghent University Hospital, The Department of Nuclear Medicine, De Pintelaan 185, 9000 Ghent, Belgium. Tel.: +32 924 030 28; Fax: +32 924 038 07; olivier.dewinter@ugent.be; http://www.uznuclear.ugent.be/ 2OLV Hospital, The Department of Nuclear Medicine, Moorselbaan 164, 9300 Aalst, Belgium. Tel.: +32 537 244 77; Fax: +32 537 240 89; pieter.de.bondt@olvz-aalst.be.

Background Several studies have shown that longitudinal systolic function and left ventricular filling pressures, as assessed with tissue Doppler imaging, predict exercise capacity. Aim The aim of this study was to evaluate whether natriuretic peptides and inflammatory parameters can independently predict maximum oxygen uptake at peak exercise (Vo 2 max) on top of tissue Doppler imaging–derived markers. Methods We evaluated 142 patients (age 70 ± 6 years, 77% men) with known or suspected coronary artery disease and a preserved left ventricular ejection fraction (≥50%). All patients underwent bicycle spiroergometry, and N-terminal pro–B-type natriuretic peptide levels were determined. Cytokines (IL-6 and soluble tumor necrosis factor receptors 1 and 2) and high-sensitivity C-reactive protein were measured as inflammatory markers. Tissue Doppler imaging was applied to evaluate peak long axis sytolic velocities (Sm) and early mitral annulus velocities (E′). Ratio of early transmitral flow (E) to E′ was assessed as marker of left ventricular filling. Analysis of variance, comparing Vo 2 max quartiles, was used to determine univariate predictors and linear regression to determine multivariate Vo 2 max predictors. Results Average Vo 2 max was 18.5 ± 5.7 mL/kg per minute (range 6-36.6). Compared with the highest quartile, patients with low Vo 2 max were more frequently women ( P 2 max categories. Longitudinal myocardial velocities increased, and E/E′ decreased along with increasing Vo 2 max. In multivariate linear regression analysis, Vo 2 max was independently predicted by sex, glucose, Sm, E/E′, and cytokine levels. Conclusion Maximum oxygen uptake at peak exercise in patients with known or suspected coronary artery disease and preserved systolic function was independently predicted by inflammatory makers on top of tissue Doppler–derived systolic and diastolic function.

Screening for coronary artery disease (CAD) in hemodialysis patients is hampered by contraindications and/or limitations of the available techniques in this population. Myocardial perfusion scintigraphy (MPS) using dipyridamole has been considered inaccurate due to abnormally high basal levels of adenosine in uremia that could blunt the vasodilatory response. Since dobutamine may be more reliable, we directly compared the two in patients on hemodialysis. We performed MPS at rest and after separate dipyridamole or dobutamine stress in 121 chronic hemodialysis patients. More numerous, larger, and more intense reversible lesions were induced with dobutamine than with dipyridamole, mainly in the anteroseptal segments. Reversibility with dipyridamole but not dobutamine MPS was independently and strongly related with mortality associated with CAD and with fatal and non-fatal CAD. We hypothesize that the chronotropic action of dobutamine induced alterations of wall motion, leading to spurious perfusion defects, not unlike artifacts seen with left bundle branch block. Our study shows that even though dobutamine induced more pronounced myocardial ischemia than dipyridamole in chronic hemodialysis patients, dipyridamole MPS more accurately identifies patients at high risk for subsequent cardiac death or non-fatal CAD than dobutamine.