Systematic assessment of procedural parameters, influence on downstream testing and 12-month outcomes of a CT-myocardial perfusion service.

Aims: This study describes the real-world referral pattern of patients to a CT myocardial perfusion service, the technical issues associated with providing the service, the results of the studies, and the subsequent downstream utilization of other investigations, and patient outcomes.

Methods And Results: 115 consecutive patients underwent CTA, dynamic rest and dipyridamole-stress perfusion scanning. There were 29 (25%) and 14 (12%) patients who had reversible defects and fixed defects respectively, indicating abnormal flow reserve and previous infarction respectively. In the patients with fixed defects, delayed hyperenhancement was noted in all, indicative of prior infarction, scarring and non-viability. With the existing CTA Appropriateness Criteria, the categorization of "Appropriate," "Of Uncertain Appropriateness", and "Inappropriate" would have been applied to 25%, 25% and 50% of the present studies respectively. Up to 72% could have been referred for ischemia evaluation with other modalities of functional imaging after the non-diagnostic CT angiogram. Follow up was complete in 113 subjects (98%) over a period of 14 ± 8 months. In the 29 patients with abnormal flow reserve and CAD, 62% underwent invasive angiography and 94%, angioplasty within a 90-day period. In the patients who underwent angioplasty, all remained free of myocardial infarction or death and 88% remained free of myocardial infarction, death or readmission over a mean of 14 ± 8 months.

Conclusion: A CT-myocardial perfusion service provided measures of ischemia and infarct detection over that of CTA alone. The information was utilized clinically by doctors to support a strategy of referral to revascularization versus conservative medical management.