Prevalence and clinical significance of incidental findings on CT attenuation correction for myocardial perfusion imaging.

BACKGROUND: The appropriate clinical approach to incidentally detected lesions (IDLs) on CT attenuation correction (CTAC) images in myocardial perfusion imaging (MPI) remains uncertain. We sought to establish their prevalence and clinical significance in a large cohort and compared to previous studies to help provide further clarity and guide future clinical practice. METHODS AND RESULTS: A total of 3758 MPI studies were reviewed retrospectively. IDLs of potential clinical significance-not known before MPI - were reported in 245 (6.5%) of these cases. Following appropriate further investigation/follow-up, these were of proven clinical significance in 30 (12.2%) cases with 14 patients (5.7%) harboring previously undiagnosed or progressive malignancies. The positive predictive value (PPV) for clinically significant incidental findings on CTAC images was 17.2% and the PPV value for incidental malignant findings was 8.0%. CONCLUSION: Although incidental findings on CTAC images in MPI are common and often clearly insignificant at time of MPI reporting, many are clinically significant with a relatively high positive predictive value. This is especially so for malignancies. Our findings, therefore, in combination with previous studies as described here support routine reporting and appropriate further investigation of incidental CTAC findings in MPI.

Interaction between the effects of proton pump inhibitors and aspirin on gastric wall sestamibi uptake on myocardial perfusion imaging.

BACKGROUND: Increased gastric wall activity on myocardial perfusion imaging (MPI) is associated with proton pump inhibitor (PPI) therapy; however, the mechanism is unknown. We proposed a role for gastric mucosal prostaglandin synthesis and asked whether concurrent use of aspirin would antagonize this effect. METHODS: An observational study was performed of 319 patients undergoing technetium-99m sestamibi (MIBI) rest/stress MPI. We assessed the effects of taking PPIs, aspirin and their interaction on the principle outcome of clinically significant gastric wall activity. RESULTS: The outcome was observed in 13% of patients taking neither a PPI nor aspirin, 22% of those taking aspirin only, 51% taking a PPI only and 33% of those taking both. Adjusted odd ratios (95% confidence intervals) were 6.3 (CI 2.8-14.0; p < .001) for taking a PPI only, 1.8 (CI 0.8-3.9; p = .16) for taking aspirin only, and 3.0 (CI 1.4-6.5; p = .005) for taking the combination of a PPI and aspirin. There was evidence of negative statistical interaction between the two drug effects using additive (p = .006) and multiplicative (p = .016) scales. CONCLUSIONS: PPI use was strongly associated with enhanced gastric wall activity on MPI; however, concurrent aspirin appears to reduce the effect. Enhanced local prostaglandin synthesis may mediate the PPI effect.

An audit of ventilation and perfusion SPECT reporting for the diagnosis of pulmonary embolism in a tertiary cardiothoracic centre.

The aim of the study was to identify reporting patterns of ventilation and perfusion single-photon emission computed tomography (V/Q SPECT) scans done in our department over 3 months in 2016. Factors impacting on reporting and patient groups that would most benefit from the addition of low-dose computed tomography (CT) to V/Q SPECT were analysed. Among 178 patients, 173 (97.2%) had a definitive (positive/negative) report and 2.8% had an equivocal report. As the majority of the equivocal reports were seen in patients aged ≥70 years, we believe that addition of low-dose CT with V/Q SPECT to this patient group will reduce the non-diagnostic rate.