Feasibility, diagnostic performance and clinical value of an abbreviated echocardiography protocol in an out-patient cardiovascular setting: a pilot study.

BACKGROUND: There has been a growing demand for echocardiography services over the last 5 years, with this supply-demand mismatch exacerbated by the COVID-19 pandemic. Prior studies have suggested a high proportion of normal findings among echocardiograms requested for patients without known cardiovascular disease, particularly in low-risk cohorts. This pilot study investigates the role of an abbreviated echocardiography protocol in improving access to echocardiography services in a low-risk outpatient setting within the rapid access chest pain (RACP) clinic. METHOD: A retrospective review of electronic medical records and transthoracic echocardiography (TTE) studies for 212 patients from RACP clinic in 2019 (cohort A), prior to the introduction of the abbreviated echocardiography protocol, and 175 patients seen in the RACP clinic in 2021 (cohort B) was performed. The outcomes measured include the echocardiography referral burden from RACP clinic, waiting time for a TTE and echocardiography findings. RESULTS: 33% and 45% of patients seen in the RACP clinic in 2019 and 2021, respectively, were referred for a TTE. The most common indications include chest pain (50%), dyspnoea (19%) and palpitations (11%). Abnormal findings were identified in 36% of TTEs performed in cohort A and 13% in cohort B. The median echocardiogram study time was significantly shorter in cohort B (7 min vs 13 min, p < 0.00001), with a lower number of images acquired (43 vs. 62, p < 0.00001). The median waiting time for an echocardiography in cohort B was significantly shorter (median: 14 days vs. 42 days in 2019, p < 0.00001). No major pathologies were missed on a retrospective review of these images. CONCLUSION: Our study demonstrates that an abbreviated echocardiography protocol has potential to improve access to echocardiography services through increasing scheduling capacity, without compromising diagnostic performance in a low-risk outpatient population.

First experience of combined cardiac PET/64-detector CT angiography with invasive angiographic validation.

PURPOSE: Despite modern CT systems and expert evaluators, the diagnostic performance of coronary CT angiography is limited by overestimation of vessel stenosis which reduces the positive predictive value (PPV) of the test. The aim of this study was to evaluate the performance of combined cardiac PET/64-detector CT angiography. METHODS: Included in this retrospective study were 33 consecutive patients (5 women, 28 men; mean age 61.6 years, range 47-87 years, mean BMI 27.3+/-5.2 kg/m(2)) with clinically suspected flow-limiting coronary artery disease who underwent combined cardiac PET/64-detector CT angiography and invasive angiography. Combined PET/CT images were reported by an experienced dual-accredited radiologist/nuclear physician. An experienced cardiac CT radiologist re-read the CT images without PET. Stenotic disease was defined as >50% vessel narrowing. Invasive coronary angiography was used as a reference standard. Local ethics committee approval and patient consent were obtained. RESULTS: CT angiography (without PET data) was concordant with invasive angiography in 31/33 patients and at a patient level, the sensitivity in detecting significant coronary artery lesions was 100%, the specificity was 82%, the PPV was 92% and the negative predictive value (NPV) was 100%. Using combined PET/CT angiography the findings were concordant with invasive angiography in 32/33 patients and at a patient level, the sensitivity was 96%, the specificity was 100%, the PPV was 100% and the NPV was 91%. CONCLUSION: The use of integrated cardiac PET/64-detector CT angiography is feasible and appears to improve some aspects of the diagnostic performance of 64-detector coronary artery angiography in detecting coronary artery disease.

Cardiac 82Rubidium PET/CT: initial European experience.

PURPOSE: Myocardial perfusion with PET/CT has advantages over conventional SPECT. We describe our initial European experience using (82)Rubidium-PET/CT, as part of a clinical myocardial perfusion service. METHODS: We studied the first 100 patients (64 male; 36 female, mean age = 60: SD +/-12.5y, mean body mass index = 30: SD +/-6.9kg/m( 2 )) who underwent (82)Rubidium cardiac PET/CT in our institution. Thirty patients had recently undergone coronary angiography. Patients underwent imaging during adenosine infusion and at rest. Images were acquired over 5 minutes using a GE-PET/CT instrument. Image quality was described as good, adequate or inadequate. Images were reported patient-by-patient by a minimum of five nuclear medicine physicians. A segment-by-segment analysis (17-segment model) was also performed. RESULTS: Image quality was good in 77%, adequate 23% and inadequate 0%. There was no statistical difference in image quality between obese and non-obese patients (Fisher's exact test, p = 0.2864). 59% had normal perfusion studies, 29% had inducible ischaemia, 12% had myocardial infarction (11% with super added ischaemia). There was reduced (82)Rubidium uptake in 132/1700 segments during stress. There was reduced (82)Rubidium uptake at rest in 42/1700 segments. The (82)Rubidium PET/CT findings were consistent with the angiographic findings in 28/30 cases. CONCLUSION: We show that, even from initial use of (82)Rubidium, it is possible to perform myocardial perfusion studies quickly with good image quality, even in the obese. The PET findings correlated well in the third of the cases where angiography was available. As such, (82)Rubidium cardiac PET/CT is likely to be an exciting addition to the European nuclear physician/ cardiologist's radionuclide imaging arsenal.