Sources of Apical Defects on a High-Sensitivity Cardiac Camera: Experiences from a Practice Performance Assessment

Abstract

Apical perfusion artifacts seen on a high-sensitivity camera warranted a practice performance assessment to evaluate contributions from soft-tissue attenuation, patient positioning, and image processing techniques. Methods: Cardiac perfusion studies (n 5 534) spanning 5 mo were retrospectively reviewed. Images were acquired with the patient in the upright position, and attenuation correction was used. Regression analysis and contingency tables correlated clinical data to the presence of apical artifacts. Results: There was a positive correlation of with female sex (x 2 5 32, P , 0.001), degree of overlying soft tissues (x 2 5 20, P , 0.002), and breast cleavage (x 2 5 7, P , 0.008) and a negative correlation with angiography-confirmed disease (x 2 5 6, P , 0.02). There was moderate interobserver agreement between 2 observers in determining the presence of apical defects (k5 0.44, 95% confidence interval 5 0.19-0.69), and there was a perceived improvement of apical defects using fewer iterative updates (x 2 5 8, P , 0.003). Conclusion: An understanding of sources contributing to imaging artifacts is a crucial portion of quality assessment in radiology and nuclear medicine. A practice performance assessment study at our institution showed that apical artifacts on a new-generation cardiac camera can be partially attributed to overlying soft-tissue attenuation and ameliorated by altering the reconstruction.Key Words: cardiology (basic/technical); instrumentation; quality assurance; iterative reconstruction; myocardial perfusion; practice performance assessment J Nucl Med Technol 2013; 41:197-202 DOI: 10.2967/jnmt.113.124198 Myocardi al perfusion imaging is susceptible to a wide variety of artifacts that mimic perfusion defects (1-3). These can arise from several sources, including the patient, imaging system, and processing techniques. Characterization of these defects is important, because artifacts can lower the specificity for detection of true cardiac perfusion abnormalities.Examinations performed on a single high-sensitivity, dedicated cardiac camera in our institution using resolution recovery appeared to result in a substantially higher rate of apparent apical perfusion defects (#17 of the American Heart Association segment model) (4). These artifacts were only partially, and usually marginally, ameliorated by attenuation correction. The objective of this practice performance assessment project (http://en.wikipedia.org/wiki/ American_Board_of_Medical_Specialties) was to measure the rate and severity of these defects and to characterize the clinical correlates on this single system. By considering the effects of reconstruction algorithms, we developed a plan to ameliorate these defects. We then remeasured defect severity after modifying the reconstruction parameters. MATERIALS AND METHODSA quality initiative waiver was approved by the institutional review board for this retrospective study. Practice Performance AssessmentA goal of maintenance of certification part 4 projects is the identification and measu...

A study of false apical defects in myocardial perfusion imaging with SPECT/CT

“…The false defects mask real defects and lead to interpretation uncertainties. The benefit of CT-AC has been questioned [11][12][13][14][15][16] and the discussion continues to the present day [17][18][19][20][21].…”