In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser.
Did you know that your browser is out of date? To get the best experience using our website we recommend that you upgrade to a newer version. Learn more.

PACIFIC - First Head-to-Head Comparison of Non-Invasive Coronary Artery Imaging

Rome, Italy – 29 August, 2016: For patients presenting for the first time with suspected coronary artery disease (CAD) clinicians have had a number of non-invasive diagnostic tests to choose from, but little evidence for which is best.

Now, findings from the PACIFIC trial may offer some guidance.

The first head-to-head comparison of the most commonly used non-invasive techniques to evaluate myocardial perfusion or coronary artery stenosis severity found that positron emission tomography (PET) had more diagnostic accuracy than either single photon emission computed tomography (SPECT) or coronary computed tomography angiography (CCTA), researchers reported during a Hot Line session at ESC Congress 2016.

“At present, there is little consensus about the choice of non-invasive imaging modality, and European and US guidelines do not advocate for any one over another,” said  Ibrahim Danad, MD,  from VU University Medical Center, Amsterdam, who presented the findings.

“The vast majority of studies used invasive coronary angiography as a reference standard, which may lead to erroneous interpretations. These data represent the first comprehensive evaluation of coronary artery disease and will help to guide the clinician to choose the appropriate non-invasive test for his or her patients.”

PACIFIC (which stands for Prospective Head-to-Head Comparison of Coronary CT Angiography, Myocardial Perfusion SPECT, PET, and Hybrid Imaging for Diagnosis of Ischemic Heart Disease using Fractional Flow Reserve as Index for Functional Severity of Coronary Stenoses) was a single centre study that included 208 patients with suspected CAD.

Initially, all patients underwent the gold standard diagnostic test – invasive coronary angiography -  which requires threading a catheter into the coronary artery to obtain x-rays and assess intracoronary pressure (fractional flow reserve, or FFR).

This test showed that 44.2% of patients had hemodynamically significant CAD.

Patients then received non-invasive PET, SPECT and CCTA as well as some “hybrid” combinations of PET and CCTA or SPECT and CCTA designed to combine functional and anatomical assessments.

Comparing results of these non-invasive results to the gold standard results, investigators showed that PET was significantly more accurate (85%) for diagnosing coronary ischemia as compared to CCTA (74%, P<0.01) and SPECT (77%, P < 0.01).

Sensitivity was 87% for PET, 90% for coronary CTA and 57% for SPECT, while specificity was 84% for PET, 60% for coronary CTA and 94% for SPECT, according to the researchers.

Additionally, diagnostic accuracy was not enhanced by either hybrid CCTA/SPECT  or CCTA/PET, and instead resulted in an increase in false negatives and decrease in false positive results (p<0.001), noted Professor Danad..

“This study’s findings are novel and, to our knowledge, represent the first of its kind to evaluate diagnostic performance of non-invasive imaging modalities against a widely considered reference standard for functionally significant CAD.”

“The results will definitely spark further research. There is always a lot of discussion whether we need to choose SPECT or PET as the initial functional test for our patients. I think that we need to invest more in clinical PET imaging, which will be future. It is more convenient for patients in terms of time, accuracy and radiation dose.“


Notes to editor

Sources of funding: None

Disclosures: Dr. Danad has no relevant disclosures.


ESC Press Office
For background information, please contact the ESC Press Office at

For press enquiries, please contact, the Media & Press Coordinator, Jacques Olivier Costa: +393427028575 

For independent comment on site, please contact the ESC Spokesperson coordinator, Celine Colas: +393402405148 

To access all the scientific resources from the sessions during the congress, visit ESC Congress 365.  

About the European Society of Cardiology

The European Society of Cardiology brings together health care professionals from more than 120 countries, working to advance cardiovascular medicine and help people lead longer, healthier lives.

About ESC Congress 2016

ESC Congress is the world’s largest gathering of cardiovascular professionals contributing to global awareness of the latest clinical trials and breakthrough discoveries. ESC Congress 2016 takes place 27 to 31 August at the Fiera di Roma in Rome, Italy. The scientific programme is here. More information is available from the ESC Press Office at

This press release accompanies both a presentation and an ESC press conference at the ESC Congress 2016. Edited by the ESC from material supplied by the investigators themselves, this press release does not necessarily reflect the opinion of the European Society of Cardiology. The content of the press release has been approved by the presenter.