Combined PET/CT with thoracic contrast-enhanced CT in assessment of primary cardiac tumors in adult patients

Scope of PET imaging in the evaluation of cardiac tumors

Cardiac and pericardial masses can be categorized as neoplastic (either benign or malignant), non-neoplastic (such as thrombus or pericardial cysts), or normal variants of the cardiac structure. Diagnosing these masses can be challenging, and various imaging modalities are available, with each of them having advantages and pitfalls. Echocardiography is typically the first test used for the evaluation and detection of cardiac masses, as it is widely accessible, portable, and provides a comprehensive assessment of cardiac function and valves without the use of ionizing radiation. However, it may not be helpful in some cases, such as evaluating the extracardiac extension of the mass or characterizing tissue. On the other hand, cross-sectional imaging can provide a three-dimensional data set with excellent spatial resolution. Still, it requires ionizing radiation and intravenous iodinated contrast, and its functional evaluation of the heart may be relatively limited. 18F-FDG PET/CT helps determine 18F-FDG PET/CT is a crucial molecular imaging modality to assess and differentiate benign and malignant cardiac tumors noninvasively and helps in treatment planning and prognostication. Currently, studies evaluating the role of 18F-FDG PET/CT in cardiac tumors are limited to case reports and single center studies.

18F-FDG PET/CT and contrast-enhanced CT in the diagnosis of Castleman disease

OBJECTIVE

Castleman disease (CD) is a rare group of lymphoproliferative disorders, which is easily confused with lymphoma or other solid tumors. Hence, this study aimed to investigate the diagnostic role of ¹⁸F-FDG PET/CT and contrast-enhanced CT (CECT) in patients with CD.

METHODS

Clinicopathological characteristics, and ¹⁸F-FDG PET/CT and CECT findings and parameters were retrospectively reviewed in 32 patients with CD.

RESULTS

These 32 patients (12 males, 20 females; median age, 41 years) consisted of 17 unicentric CD (UCD) patients and 15 multicentric CD (MCD) patients. Compared with MCD, UCD had a higher prevalence in female (82.4% vs. 40.0%) and hyaline vascular subtype (94.1% vs. 40.0%) (P < 0.05). FDG uptake was avid in all cases, including moderate uptake in 7 cases and intense uptake in 25 cases. The median SUVmax, SUVmean, MLV, and TLG of all cases were 4.4 (range, 1.4-23.6), 2.7 (range, 1.1-15.2), 26.6 (range, 4.8-393.0), and 78.8 (range, 9.4-1545.6), respectively. The lesions of 29 cases showed homogeneous enhancement, and marked enhancement was observed in 27 cases. ¹⁸F-FDG PET/CT corrected 6.3% CECT diagnoses, while CECT corrected 37.5% PET/CT diagnosis. The accuracy of combined PET/CT and CECT was superior to PET/CT or CECT alone (78.1%, 31.3%, and 62.5%). Besides, higher SUVmax and SUVmean were found in male subjects, MCD, and plasma cell subtype (P < 0.05), while higher MLV and TLG were observed in larger lesion size and volume (P < 0.05).

CONCLUSION

Castleman disease most commonly appears as marked and homogeneous enhancement meanwhile with moderate or intense FDG uptake. ¹⁸F-FDG PET/CT combined with CECT was the effectively diagnostic modality for CD. The glucose metabolism of CD was associated with gender, clinical classification, histopathological classification, and lesion size and volume.

PET/CT morphology and cardiac conduction disorders help discriminate primary cardiac lymphoma from primary cardiac sarcoma

BACKGROUND

Primary cardiac lymphoma (PCL) and primary cardiac sarcoma (PCS) are similar in clinical presentation but differ in management and outcomes. We aim to explore the role of PET morphology and clinical characteristics in distinguishing PCL from PCS.

METHODS

Pretreatment 18F-FDG PET/CT and contrast-enhanced CT were performed in PCL (n = 14) and PCS (n = 15) patients. Patient demographics, overall survival, and progression-free survival were reviewed. PET/CT morphological and metabolic features were extracted. Specifically, R_Kurtosis, a PET-morphology parameter reflecting the tumor expansion within the heart, was calculated.

RESULTS

Compared with PCS, PCL occurred at an older age, resulted in more cardiac dysfunctions and arrhythmias, and showed higher glucometabolism (SUVmax, SUVpeak, SUVmean, MTV, and TLG). Curative treatments improved survival for PCL but not for PCS. Multivariable logistic regression identified R_Kurtosis (OR = 27.025, P = .007) and cardiac conduction disorders (OR = 37.732, P = .016) independently predictive of PCL, and classification and regression tree analysis stratified patients into three subgroups: R_Kurtosis ≥ 0.044 (probability of PCL 88.9%), R_Kurtosis < 0.044 with conduction disorders (80.0%), and R_Kurtosis < 0.044 without conduction disorders (13.3%).

CONCLUSION

PET-derived tumor expansion pattern (R_Kurtosis) and cardiac conduction disorders were helpful in distinguishing PCL from PCS, which might assist the clinical management.

Diagnostic challenges in primary cardiac lymphoma, the opportunity of 18F-FDG PET/CT integrated with contrast-enhanced CT

BACKGROUND

The purpose of this study was to retrospectively evaluate the value of 18F-FDG PET/CT integrated with contrast-enhanced CT (CECT) in the differential diagnosis of primary cardiac lymphomas (PCLs) and primary cardiac angiosarcomas (PCAs).

METHODS

Clinical and imaging data of patients with PCLs and PCAs were collected. All patients underwent preoperative 18F-FDG PET/CT and thoracic CECT. The enhancement pattern and tumor morphology were analyzed using CECT images. The intensity- and volume-based PET parameters of cardiac lesions were analyzed. The performance characteristics of all parameters were assessed.

RESULTS

Nine patients with PCL and eight patients with PCA were analyzed. There were significant differences in SUVmax (t = 3.790, P = .002), SUVmean (t = 4.273, P = .001), metabolic tumor volume (U = 13.00, P = .027), tumor-to-liver ratio (U = 10.00, P = .011), and total lesion glycolysis (U = 4.0, P = .001) between PCLs and PC18As. There were significant differences in the enhancement pattern of tumors (P = .002) and tumor morphology (P = .015). The combination of F-FDG PET/CT and CECT improved the diagnostic accuracy, and the combination cutoff (SUVmean > 5.17) could reach 100%, but the difference was not statistically significant (P > .05).

CONCLUSION

The intensity- and volume-based PET parameters of PCL were significantly higher than those of PCA. The enhancement pattern and tumor morphology were also different. According to these characteristics, the two most common types of primary cardiac malignancies can be differentiated.

Massive left atrial thrombus evades multimodality imaging as a myxoma in a bicaval heart transplant recipient

Intracardiac masses are an extremely rare and poorly described complication following a bicaval heart transplantation. We describe the case of an asymptomatic 62-year-old male with a large left atrial mass found incidentally on transthoracic echocardiography 6 years post-transplant. A battery of additional imaging tests was ordered including transesophageal echocardiography, ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography, and T1 and T2 magnetic resonance imaging. Although imaging biomarkers were generally nonspecific, the mass was most consistent with a cardiac myxoma. However, intraoperative findings confirmed by pathology revealed a massive organizing thrombus. The patient had an uneventful recovery after surgical removal of the mass. Our case highlights a very rare phenomenon in heart transplant recipients which remains a unique diagnostic challenge even with current advances in imaging.

COVID-19 associated mucormycosis: evolving technologies for early and rapid diagnosis

The post-coronavirus disease (COVID-19) mucormycosis is a deadly addition to the pandemic spectrum. Although it’s a rare, aggressive, and opportunistic disease, the associated morbidity and mortality are significant. The complex interplay of factors aggravating CAM is uncontrolled diabetes, irrational and excessive use of antibiotics, steroids, and an impaired immune system. Recently, India has been witnessing a rapid surge in the cases of coronavirus disease-associated mucormycosis (CAM), since the second wave of COVID-19. The devastating and lethal implications of CAM had now become a matter of global attention. A delayed diagnosis is often associated with a poor prognosis. Therefore, the rapid and early diagnosis of infection would be life-saving. Prevention and effective management of mucormycosis depend upon its early and accurate diagnosis followed by a multimodal therapeutic approach. The current review summarizes an array of detection methods and highlights certain evolving technologies for early and rapid diagnosis of CAM. Furthermore, several potential management strategies have also been discussed, which would aid in tackling the neglected yet fatal crisis of mucormycosis associated with COVID-19.