ISCHEMIA is a Cleerly analysis module that produces an index for each analyzable coronary vessel indicating whether ischemia is likely present, using a threshold calibrated against invasive fractional flow reserve measurements above or at or below 0.80. It integrates coronary atherosclerosis and vascular morphology characteristics from a coronary CT angiography study into a single physiologic measure, giving the reading physician an actionable estimate of a patient's likely ischemic burden.

In published multicenter trials, the module was compared against invasive FFR as the reference standard and against other non-invasive tests such as CT-derived flow reserve, stress perfusion imaging, and PET, showing consistent or higher diagnostic accuracy across those comparisons. It is delivered as part of the same CT angiography workflow used for Cleerly's plaque and stenosis reporting.