Journal of Nuclear Cardiology最新文献

Background: In suspected cardiac sarcoidosis, the interpretation of myocardial fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) can be challenging and can have important clinical implications. In this study, we aimed to study the prevalence of lateral wall FDG uptake in patients with suspected cardiac sarcoidosis, particularly in patients with ventricular pacing (V-pacing) or left bundle branch block (LBBB).

Methods: We retrospectively reviewed sarcoidosis-protocol FDG PET/CT studies performed at our center for clinical suspicion for cardiac sarcoidosis where an electrocardiogram (ECG) was available within three months of the PET/CT. We identified the absence or presence of LBBB or V-pacing on ECG, reviewed perfusion and FDG PET/CT findings, and classified all patients according to whether they met Heart Rhythm Society (HRS) criteria for cardiac sarcoidosis or probable cardiac sarcoidosis (meeting all HRS criteria except biopsy-proven disease and having extracardiac FDG uptake present). We also reviewed the results of cardiac magnetic resonance imaging (MRI) and follow-up FDG PET/CT imaging if applicable. Patients were followed until a composite endpoint of durable left ventricular assist device placement, cardiac transplant, or death.

Results: Five hundred thirty patients met inclusion criteria, 169 patients (31.9%) had V-pacing (N = 133 (78.7%)) or LBBB (N = 36 (21.3%)) on ECG, and 361 (68.1 %) had neither. Sixty-six of the 169 patients (39.1%) with V-pacing or LBBB had focal or focal-on-diffuse lateral wall myocardial FDG uptake without an associated perfusion defect, compared with 39 of the 361 patients (10.8%) without either (P < 0.001). Of the 66 patients with V-pacing/LBBB and lateral wall FDG uptake, 27 (40.9%) underwent cardiac MRI, and only six (22.2 %) had evidence of lateral wall late gadolinium enhancement (LGE). Twenty-four (36.4%) of the 66 patients had extracardiac FDG uptake, and these were the only patients with definite/probable cardiac sarcoidosis in follow-up. There was no difference in outcomes between patients with or without definite/probable cardiac sarcoidosis stratified by lateral wall myocardial FDG uptake pattern.

Conclusions: Lateral wall myocardial FDG uptake without an associated perfusion defect was significantly more common among patients with LBBB or V-pacing referred for sarcoidosis FDG PET/CT imaging than among those without LBBB or V-pacing. LBBB and V-pacing should be considered as potential causes of lateral wall myocardial FDG uptake in patients with and without biopsy-proven sarcoidosis, and diagnoses other than cardiac sarcoidosis should be considered when this pattern is present but metabolically active extracardiac sarcoidosis is absent.

Background: Early diagnosis of transthyretin-amyloid cardiomyopathy (ATTR-CM) is key to early treatment initiation. Recent guidelines recommend using both single-photon emission computed tomography (SPECT) and planar imaging. However, whether combined use of planar imaging and SPECT improves diagnostic accuracy compared with histological confirmation is unclear. We assessed the significance of using both planar imaging and SPECT with bone-seeking tracer cardiac scintigraphy for diagnosing endomyocardial biopsy (EMB)-proven ATTR-CM.

Methods and results: This retrospective observational study included 117 consecutive patients with suspected ATTR-CM who underwent bone-seeking tracer cardiac scintigraphy, among whom 42 underwent EMB based on positive planar imaging (Perugini grade ≥2) and/or positive SPECT results (uptake score ≥1). Of these 42 patients, 38 (91%) were histologically diagnosed with ATTR-CM. Among patients with concordantly positive planar imaging and SPECT, 36/37 (97%) were diagnosed with ATTR-CM. Among patients with discordant findings, 2/2 (100%) with negative planar but positive SPECT findings were diagnosed with ATTR-CM, whereas 0/3 (0%) with positive planar but negative SPECT findings were diagnosed with ATTR-CM. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SPECT for detecting transthyretin amyloid deposition on EMB were 100%, 75%, 97%, 100%, and 98%, respectively. On SPECT, tracer uptake was consistently and maximally observed in the interventricular septum in all cases of EMB-proven ATTR-CM (P < 0.001).

Conclusions: SPECT has a high diagnostic ability in detecting EMB-proven ATTR-CM and effectively complements planar imaging by mitigating its limitations, reducing both false-positive and false-negative findings of planar imaging alone.

Background: Machine learning (ML) holds potential for improving risk assessment in patients with suspected or confirmed coronary artery disease (CAD). However, certain approaches offer greater benefit than others for this task, particularly to capture non-linearity between variables as well as case-by-case explainability.

Methods: We included consecutive patients who underwent clinically indicated positron emission tomography (PET) imaging. Using automated machine learning (AutoML) and unseen data for performance testing, clinical and PET variables were used to train the predictive models. A logistic regression (LR) and a deep feed-forward neural network (DNN) were trained on the same data for comparison. Major adverse cardiovascular events (MACEs) included death, myocardial infarction, or coronary revascularization >90 days after imaging.

Results: We included 8,357 patients (80% for development and 20% held out for testing), 46.3% females, with a mean (standard deviation) age of 67.2 (11.7) years. The median (interquartile range) myocardial flow reserve (MFR) was 2.1 (1.6 to 2.6). After an average follow-up of 589 days, a total of 852 patients (10.2%) experienced MACEs. The AutoML achieved an area under the receiver operator curve of .82 (95% confidence interval: .79 to .85) versus .79 (.76 to .82) and .76 (.73 to .80) for the LR and the DNN models, respectively. Model explainability showed that MFR topped the list of most impactful features, followed by total perfusion defects, serum creatinine, and diastolic blood pressure.

Conclusions: An AutoML model integrating clinical and PET data discriminated MACE risk in CAD more accurately than LR or DNN models and provides interpretable patient-level explanations that can inform personalized care.

Background: The longitudinal myocardial blood flow (MBF) gradient, reflecting the basal-to-apical decline in stress MBF, has been proposed as a non-invasive marker for obstructive coronary artery disease (CAD). However, its clinical utility in Rubidium-82 (⁸²Rb) positron emission tomography (PET) remains unestablished.

Methods: This single-center retrospective study included consecutive patients who underwent rest/dipyridamole-stress ⁸²Rb PET myocardial perfusion imaging and invasive coronary angiography within 90 days from January 2012 to December 2019. Stress MBF and longitudinal gradients (basal-to-apical differences) were quantified in left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) territories. Coronary territories were stratified by coronary artery calcification (CAC) and perfusion defects (PD) into groups A (CAC-, PD-), B (CAC+, PD-), and C (PD+). Associations with CAD burden and diagnostic performance for obstructive CAD (≥50% angiographic stenosis) were evaluated using receiver operating characteristic analysis.

Results: Of 1,516 patients screened, 396 (median age: 68 years; 30.6% female) were included, contributing 1,077 coronary territories (LAD: 391; LCX: 377; RCA: 309). In LAD territory, longitudinal MBF gradients increased with CAD burden (P < 0.001) and improved diagnostic accuracy beyond relative perfusion and stress MBF (AUC 0.774 vs 0.743, P = 0.002). Conversely, gradients in LCX and RCA territories decreased with increasing CAD burden (both P < 0.001) and did not improve diagnostic performance (LCX: AUC 0.704 vs 0.715, P = 0.267; RCA: AUC 0.727 vs 0.723, P = 0.698).

Conclusions: Longitudinal stress MBF gradients derived from ⁸²Rb PET may enhance diagnostic accuracy for obstructive CAD in the LAD territory. No additional diagnostic value was observed in LCX or RCA territories.

Background: The application of hybrid stress single-photon emission computed tomography/computed tomography (SPECT/CT) imaging allows for the combined assessment of patients' exercise ability and coronary artery calcium (CAC) burden. The prognostic utility of this combined information among patients undergoing stress SPECT-myocardial perfusion imaging (MPI) remains incompletely understood.

Methods: To simulate the prognostic information that can be provided by stress SPECT/CT, we assessed 2435 patients undergoing stress SPECT-MPI and CAC scanning within six months of each other. Patients were grouped into four groups of descending stress test performance: those exercising greater than or equal to 9 minutes, exercising less than 9 minutes, undergoing pharmacologic testing while performing a walk protocol, or pharmacologic testing without walking. Patients were followed for all-cause mortality (ACM) over a mean of 9.0 ± 6.4 years.

Results: During follow-up, 291 patients (12.0%) died. There was a stepwise decrease in survival with poorer stress test performance and with increasing CAC scores. Mortality was consistently higher in patients with lower stress test performance among all CAC categories. Conversely, higher CAC scores were associated with increased mortality risk across all four stress test performance groups. Patients with CAC scores greater than or equal to 400 but exercising greater than or equal to 9 minutes had a mortality rate similar to patients with zero CAC scores who could not walk during pharmacologic stress testing (8.8 vs 8.0 per 1000 person-years, P = 0.898). A multivariable analysis identified stress test performance as the strongest adverse ACM predictor, followed by age and CAC scores.

Conclusions: The combined assessment of stress test performance and the magnitude of CAC abnormality provides highly synergistic prognostic information among patients undergoing stress SPECT-MPI.