[Show abstract][Hide abstract] ABSTRACT: The sensitivity of stress myocardial perfusion scintigraphy for detecting coronary artery disease (CAD) in patients with multivessel CAD is high. 1-4 However, its ability to predict the presence of multivessel disease is limited. It has been suggested that the presence of left main or multivessel disease is missed in up to 50% of cases. 5,6 The possible reasons for this include balanced perfusion abnormality, where the absence of a normal reference segment limits sensitivity, early plateau of tracer uptake, which limits detection of borderline stenoses, and early stoppage of exercise as a result of symptoms or signs due to the severest lesion. There is evidence that ancillary clinical, exercise, and scan variables can improve the sensitivity of a gated SPECT myocardial perfusion study for detection of multivessel CAD. 7 These include poor exercise tolerance and development of chest pain and/or electrocardiographic evidence of ischemia at a low exercise workload, 8 increased lung/heart tracer uptake ratio, 9 and transient ischemic dilation of the left ventricle following stress (TID), which was shown to be a specific but fairly insensitive marker of multivessel CAD. Initial studies with planar Tl-201 imaging found a cut-off TID ratio of 1.12 to have the best sensitivity and specificity for detecting multivessel CAD. A subsequent study with dual-isotope imaging reported an optimal cut-off of 1.22. 10 Other approaches include integration of functional assessment by gated SPECT with conventional perfusion analysis; 3,11 comparison of RV to LV activity,
Journal of Nuclear Cardiology 03/2009; 16(1):4-5. · 2.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
Journal of Nuclear Cardiology 10/2006; 13(5):675-84. · 2.85 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The imaging sequences used in first pass (FP) perfusion to date have important limitations in contrast-to-noise ratio (CNR), temporal and spatial resolution, and myocardial coverage. As a result, controversy exists about optimal imaging strategies for FP myocardial perfusion. Since imaging performance varies from subject to subject, it is difficult to form conclusions without direct comparison of different sequences in the same subject. The purpose of this study was to directly compare the saturation recovery SSFP technique to other more commonly used myocardial first pass perfusion techniques, namely spoiled GRE and segmented EPI. Differences in signal-to-noise ratio (SNR), CNR, relative maximal upslope (RMU) of signal amplitude, and artifacts at comparable temporal and spatial resolution among the three sequences were investigated in computer simulation, contrast agent doped phantoms, and 16 volunteers. The results demonstrate that SSFP perfusion images exhibit an improvement of approximately 77% in SNR and 23% in CNR over spoiled GRE and 85% SNR and 50% CNR over segmented EPI. Mean RMU was similar between SSFP and spoiled GRE, but there was a 58% increase in RMU with SSFP versus segmented EPI.
Magnetic Resonance in Medicine 12/2005; 54(5):1123-9. · 3.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To study a first-pass myocardial perfusion imaging method, such that long-axis imaging slices are obtained rotationally around the short-axis centroid of the left ventricular cavity, in order to improve myocardial coverage and better delineate the basal and apical myocardium.
This rotational long-axis (RLA) method was examined in 12 volunteers and compared to the perfusion images from conventional parallel short-axis (PSA) acquisitions in terms of the contrast to noise ratio (CNR), relative signal upslope and myocardial coverage. Both RLA and PSA first-pass perfusion images were acquired on each volunteer with otherwise identical imaging parameters using the partial Fourier saturation recovery steady state gradient echo sequence with refocused magnetization (TrueFISP) technique.
Compared to PSA, RLA perfusion images with identical imaging parameters on the same subject exhibit an average of near 30% improvement in total myocardial area imaged. In addition, true basal and apical myocardium was seen on RLA, but not on PSA. The mean CNR and relative upslope were similar between the two techniques.
This RLA perfusion imaging scheme is superior to the conventional PSA approach in terms of extent myocardial coverage and delineation of basal and apical regions of the left ventricle.
Journal of Magnetic Resonance Imaging 08/2005; 22(1):53-8. · 2.57 Impact Factor