Ed D. Nicol, Presenter: Nothing to Disclose

Eliana Reyes, Abstract Co-Author: Nothing to Disclose

S. Richard Underwood, Abstract Co-Author: Nothing to Disclose

Simon Peter Padley MBBS, Abstract Co-Author: Nothing to Disclose

Michael Bernard Rubens MBBS, Abstract Co-Author: Nothing to Disclose

We compared 64-MDCT coronary angiography against MPS for predicting significant coronary artery stenoses in patients with Low to Intermediate Likelihood of Coronary Artery Disease.

52 consecutive patients with low to intermediate likelihood of CAD underwent stress/rest Tc-99m tetrofosmin MPS. CT coronary angiograms were acquired on a Siemens Sensation 64 using 80mls iodinated contrast and reformatted using an Aquarius workstation, Terarecon Inc. All datasets were analyzed using a sixteen segment coronary artery model and coronary artery segments reported as <50%, 50-69%, 70-99% stenoses or occluded. MPS images were analyzed for the presence of perfusion abnormalities and their respective coronary territories identified. In addition to the comparison of the raw image data, clinical history was incorporated to allow further interpretation of MPS data.

Using MPS data with no clinical history overall correlation between MPS and CTA was 78% for MDCT lesions ≥50% (Sensitivity = 62%, Specificity= 85%, PPV= 57%, NPV= 87%) and 88% for MDCT lesions ≥ 70% (Sensitivity = 53%, Specificity= 100%, PPV= 100%, NPV= 87%). With Clinical MPS i.e. MPS data plus clinical data, the correlation with MDCT was 75% (Sensitivity = 100%, Specificity= 83%, PPV= 57%, NPV= 100%) and 94% (Sensitivity = 83%, Specificity= 96%, PPV= 72%, NPV= 98%) respectively. At vessel level, correlation was least good for LAD and RCA respectively against clinical MPS (83% and 92% for MDCT lesions ≥50%, 92% and 94% for MDCT lesions ≥70%). This disagreement is due to LAD calcification (p=0.012 at ≥50%, p=0.27 at ≥70%) and RCA motion artefact (p=0.142 at ≥50%, p=0.02 at ≥70%).

Quantification of stenoses at ≥70% correlates more closely with MPS to determine functional significance. Heavy calcification of the left coronary arteries, in particular the LAD, and motion artefact affecting the RCA image quality are responsible for the lower positive predictive value of MDCT.

If used as a substitute for MPS as a gatekeeper to coronary angiography MDCTCA stenoses of 70% should be used to determine functional significance, not 50% as is currently usual practice.

Nicol, E, Reyes, E, Underwood, S, Padley, S, Rubens, M, Sixty Four MDCT Coronary Angiography Compared with Myocardial Perfusion Scintigraphy for Diagnosis of Functionally Significant Coronary Stenoses in Patients with Chest Pain and Low to Intermediate Likelihood of Coronary Artery Disease.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011240.html