Half-time SPECT myocardial perfusion imaging with attenuation correction.

Unlabelled: Reducing acquisition time may improve patient throughput, increase camera efficiency, and reduce costs; reducing acquisition time also increases image noise. Newly available software controls the effects of noise by maximum a posteriori reconstruction while maintaining resolution with resolution-recovery methods. This study compares half-time (HT) gated myocardial SPECT images processed with ordered-subset expectation maximization with resolution recovery (OSEM-RR) (with and without CT-based attenuation correction [AC]) with full-time (FT) images obtained with a standard clinical protocol and reconstructed with filtered backprojection (FBP) and OSEM (with and without AC).

Ordered subset expectation maximization and wide beam reconstruction "half-time" gated myocardial perfusion SPECT functional imaging: a comparison to "full-time" filtered backprojection.

Objectives: Compared to filtered back projection (FBP), OSEM with resolution recovery (OSEM-RR) and wide beam reconstruction (WBR)(UltraSPECT Ltd.), which resolve resolution and suppress noise simultaneously during reconstruction, have been shown to maintain/improve myocardial perfusion SPECT quality, even with low count density half-time acquisitions. We postulated that their characteristics would be advantageous for gated SPECT, where each frame is only 1/8th the count density of the summed perfusion images.

Clinical validation of SPECT attenuation correction using x-ray computed tomography-derived attenuation maps: multicenter clinical trial with angiographic correlation.

Background: Nonuniform attenuation artifacts cause suboptimal specificity of stress single photon emission computed tomography (SPECT) myocardial perfusion images. In phantoms, normal subjects, and patients suspected of having coronary artery disease (CAD), we evaluated a new hybrid attenuation correction (AC) system that combines x-ray computed tomography (CT) with conventional stress SPECT imaging.

Methods And Results: The effect of CT-based AC was evaluated in phantoms by assessing homogeneity of normal cardiac inserts.

Clinical significance of apical thinning after attenuation correction.

Background: Apical thinning and other image changes at the apex have been described after attenuation correction of myocardial perfusion single photon emission computed tomography (SPECT) studies, but their clinical significance is unknown.

Methods And Results: We studied 102 subjects from a multicenter trial of attenuation correction, 46 with angiographic coronary artery disease and 56 normal subjects. We graded the presence and magnitude (on a 4-point scale) of apical thinning (decrease in wall thickness, best assessed in the vertical long-axis view) in both noncorrected and attenuation-corrected images.

Cerebral blood flow and anxiety in older men: an analysis of resting anterior asymmetry and prefrontal regions.

Asymmetric resting blood flow in prefrontal and hemispheric regions, assessed by single photon emission computed tomography (SPECT), was examined as a potential biological marker for enhanced trait and state anxiety in 30 older men (ages 55-81). Average and asymmetric perfusion in dorsolateral, medial, and orbital regions of the prefrontal lobes was also assessed. Results indicated a significant association between lower levels of resting dorsolateral blood flow and greater state anxiety responses to a series of stressful provocations (measured on a separate occasion).

A multicenter evaluation of commercial attenuation compensation techniques in cardiac SPECT using phantom models.

Background: Our goal was to evaluate the ability of current commercially available attenuation compensation (AC) techniques to correct for the effects of attenuation, scatter, and loss of resolution with depth, in a series of standardized phantom experiments.

Methods And Results: The following systems were evaluated: Hawkeye (GE Medical Systems), Profile (Siemens Medical Systems), Vantage Pro (ADAC Laboratories), TAC (SMV America), M-STEP (University of Michigan, Ann Arbor), TransAct (Elscint), Beacon (Marconi Systems), and PET Advance (GE Medical Systems). Studies were performed with the use of normal and ischemic myocardium in air and with technetium 99m or fluorine 18 in torso phantoms.

Combined corrections for attenuation, depth-dependent blur, and motion in cardiac SPECT: a multicenter trial.

Background: The diagnostic accuracy of cardiac single photon emission computed tomography (SPECT) is limited by image-degrading factors, such as heart or subject motion, depth-dependent blurring caused by the collimator, and photon scatter and attenuation. We developed correction approaches for motion, depth-dependent blur, and attenuation and performed a multicenter validation.

Methods And Results: Motion was corrected both transversely and axially with a cross-correlation technique.

[Analysis and trends of treatment in cancer of the lung (author's transl)].

From 1953 to 1978 3439 patients suffering from bronchial carcinoma underwent operation. Due to the changing conditions of mass X-ray early detection of lung cancer decreased. This was followed by a declining number of operations but also by an increase in pneumonectomies (1974 to 1978).