Imaging Software System Improves Heart Disease Diagnosis

The synchronized multimodal heart visualization software system used with CT angiography and SPECT myocardial perfusion imaging (MPI) improves physicians’ ability to diagnose coronary artery disease, according to a study published in The Journal of Nuclear Medicine.

Computed tomography angiography and SPECT myocardial perfusion imaging are used together to assess coronary artery disease (CAD), but researchers from the Netherlands have developed a synchronized multimodal heart visualization (SMARTVis) system to create 2D and 3D fused images, which would allow radiologists to have a clearer image of the heart.

The researchers investigated the additional diagnostic value of software-based CTA/SPECT MPI images that fused the angiography and myocardial perfusion imaging scans. The fusion system was then compared with conventional side-by-side analysis in patients with suspected CAD.

The study included 17 symptomatic patients who underwent both CTA and SPECT MPI within a 30-day period. Seven of the 17 also underwent invasive coronary angiography. The side-by-side analysis of the images (using structured CTA and SPECT reports and, second, an integrated analysis using the SMARTVis system), in addition to the reports, were assessed by four experts from two medical centers.

For the seven patients who underwent CTA, MPI, and invasive coronary angiography, there were a total of 28 therapeutic decisions (there were 68 total – four vessels each – for all 17 patients). The four readers agreed on the course of therapy for 14 cases (50 percent) in the side-by-side analysis, while three observers agreed in nine cases (32 percent). There was no consensus for the five remaining cases.

The results showed that “the fused interpretation led to a more accurate diagnosis, reflected in an increase in the individual observers’ sensitivity and specificity to correctly refer for invasive angiography eventually followed by revascularization,” the authors wrote.

The sensitivities improved for the following:

• The first observers – from 50 percent to 70 percent
• The second observers – from 60 percent to 80 percent
• The third observers – from 80 percent to 100 percent
• The fourth observers – from 80 percent to 90 percent

The specificities improved:

• The first observers – from 100 percent to 100 percent
• The second observers – from 94 percent to 100 percent
• The third observers – from 83 percent to 94 percent
• The fourth observers – from 83 percent to 83 percent

The interobserver diagnosis agreement increased from 74 percent to 84 percent and the improvement was primarily found in patients who presented with CAD in more vessels than the number of reported perfusion defects.

The researchers concluded that this integrated analysis of cardiac CTA and SPECT MPI, using the software system resulted in improved diagnostic performance for CAD.