Clinical features and prognosis of isolated cardiac sarcoidosis diagnosed using new guidelines with dedicated FDG PET/CT.

BACKGROUND: Diagnostic guidelines for isolated cardiac sarcoidosis (iCS) were first proposed in 2016, but there are few reports on the imaging and prognosis of iCS. This study aimed to evaluate the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging in predicting iCS prognosis. METHODS AND RESULTS: We retrospectively reviewed the clinical and imaging data of 306 consecutive patients with suspected CS who underwent FDG PET/CT with a dedicated preparation protocol and included 82 patients (55 with systemic sarcoidosis including cardiac involvement [sCS], 27 with iCS) in the study. We compared the FDG PET/CT findings between the two groups. We examined the relationship between the CS type and the rate of adverse cardiac events. The iCS group had a significantly lower target-to-background ratio than the sCS group (P = 0.0010). The event-free survival rate was significantly lower in the iCS group than the sCS group (log-rank test, P < 0.0001). iCS was identified as an independent prognostic factor for adverse events (hazard ratio 3.82, P = 0.0059). CONCLUSION: iCS was an independent prognostic factor for adverse cardiac events in patients with CS. The clinical diagnosis of iCS based on FDG PET/CT and new guidelines may be important.

A case of congenital left ventricular diverticulum in a patient with autosomal dominant polycystic kidney disease: possible mechanistic link between polycystin and ventricular diverticulum.

A 40-year-old woman had been followed as an outpatient to manage chronic kidney disease secondary to autosomal dominant polycystic kidney disease (ADPKD). Atrial premature contraction was found incidentally on an electrocardiogram during her regular follow-up examination. Subsequent transthoracic echocardiography detected an abnormal structure located very close to the left ventricular outflow tract (23 mm long × 15 mm wide in diastole). The structure was finally diagnosed as congenital left ventricular diverticulum (CLVD) using transesophageal echocardiography, contrast-enhanced computed tomography, and magnetic resonance imaging. Although CLVD occasionally causes intraventricular coagulation, lethal arrhythmia, and congestive heart failure, the size and location of her diverticulum remained unchanged over time and a 24-h Holter electrocardiogram showed no lethal arrhythmias. Accordingly, neither anticoagulation therapy nor surgical resection of the diverticulum was performed. To the best of our knowledge, ours is the first case of CLVD in a patient with ADPKD. Because gene abnormalities in polycystin coding are mechanistically related to the development of colonic diverticulum and abnormal cyst formation in ADPKD patients, we suspected that CLVD and abnormal cyst formation were related to the same gene abnormality in ADPKD. More case reports, case series studies, and basic research are required to determine whether CLVD in ADPKD is mechanistically associated with abnormal polycystin or just a coincidence.

Estimation of myocardial flow reserve utilizing an ultrafast cardiac SPECT: Comparison with coronary angiography, fractional flow reserve, and the SYNTAX score.

BACKGROUND: Quantitative assessment of myocardial flow reserve (MFR) by single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is challenging but may facilitate evaluation of multi-vessel coronary artery disease (CAD). METHODS: We enrolled 153 patients with suspected or known CAD, referred for pharmacological stress MPI. They underwent a 99mTc-perfusion stress/rest SPECT with an ultrafast cadmium-zinc-telluride (CZT) camera. Dynamic data were acquired and time-activity curves fitted to a 1-tissue compartment analysis with input function. K1 was assigned for stress and rest data. The MFR index (MFRi) was calculated as K1 stress/K1 at-rest. The findings were validated by invasive coronary angiography in 69 consecutive patients. RESULTS: The global MFRi was 1.46 (1.16-1.76), 1.33 (1.12-1.54), and 1.18 (1.01-1.35), for 1-vessel disease (VD), 2-VD, and 3-VD, respectively. In the 3-VD, global MFRi was lower than that in 0-VD (1.63 [1.22-2.04], P<0.0001) and 1-VD (P=0.003). Multivariate logistic regression analysis for 3-VD showed significant associations with smoking history (odds ratio [OR]: 4.4 [0.4-8.4]), left ventricular ejection fraction (OR: 61.6 [57.5-66.0]), and global MFRi (OR: 119.6 [111.5-127.7], P=0.002). A cut-off value of 1.3 yielded 93.3% sensitivity and 75.9% specificity for diagnosing 3-VD. Fractional flow reserve positively correlated with regional MFRi (r=0.62, P=0.008), and the SYNTAX score correlated negatively with global MFRi (r=0.567, P=0.0003). CONCLUSION: We developed and validated a clinically available method for MFR quantification by dynamic 99mTc-perfusion SPECT utilizing a CZT camera, which improves the detectability of multi-vessel CAD.