ARRS 2022 Abstracts

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E1258. Myocardial Dynamic CT Perfusion: How, When, and Why?
Authors
  1. Omar Garcia; Hraeb High Specialty Hospital
  2. Eric Kimura; Hraeb High Specialty Hospital
Background
In the last 2 decades, coronary CTA has demonstrated to be an excellent non-invasive diagnostic modality in patients with suspected coronary artery disease, mainly in low-intermediate pretest risk patients. The main value of coronary CTA is the very high negative predictive value that excludes the presence of significant coronary artery stenosis; however, its positive predictive value and specificity remains low, which could a limiting factor in patients with intermediate lesions (i.e., 50–69% stenosis) for whom physiological meaning of the lesion is recommended. In this context, CT perfusion was described several years ago, but its use in daily clinical practice has been limited due to radiation dose. More recently, the advent of newer high-volume coverage CT scanners (256–512 slices per rotation and a coverage of up to 16 cm) has renewed an interest of this functional technique. Initially, static perfusion during pharmacologic stress was employed with overall good results, but nowadays dynamic CT perfusion is increasingly requested, keeping radiation dose lower than conventional myocardial perfusion with SPECT and with quantitative data similar to what is considered the gold standard, PET-CT. According to literature, the diagnostic performance of the method is similar to FFRCT with reported values of sensitivity, specificity, NPV, PPV, and diagnostic accuracy of 91%, 94%, 96%, 86%, and 93%, respectively, and with AUC similar to FFR by angiography (0.876 vs 0.878). In this educational exhibit, we review the how, when, and why for performing dynamic CT perfusion, and we present representative cases of its potential clinical indications as well as the pitfalls and caveats of the method.

Educational Goals / Teaching Points
The goals of this exhibit are to show the technique of myocardial dynamic CT perfusion; show representative cases of myocardial dynamic CT perfusion in different clinical scenarios; and list potential pitfalls.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Cardiac CT perfusion is a novel technique where the CT machine acquires multiple images in cardiac stress, obtaining cardiac flow, mean transit time, and volume. The results of ischemia, inducible injury, or infarction are analyzed through a map of the left ventricle.

Conclusion
Myocardial dynamic CT perfusion is a novel technique that allows for evaluation of patients with suspected myocardial ischemia in patients with intermediate/high pre-test risk, in whom anatomic information (i.e., coronary CTA) may be inconclusive. State-of-the-art MDCT scanners reduce radiation dose and contrast volume, making it possible in current clinical practice.