ABSTRACT
Objective:To investigate the correlations between perfused lung volumes, visual scores (using perfusion SPECT/CT) and right-heart catheter (RHC) hemodynamic parameters in patients with chronic thromboembolic pulmonary hypertension (CTEPH).Methods:A total of 51 consecutive CTEPH patients (17 males, 34 females, age (59±12) years) in the First Affiliated Hospital of Guangzhou Medical University between March 2015 and July 2019 were retrospectively analyzed. All patients underwent lung perfusion SPECT/CT imaging and RHC examinations. Perfused lung volumes were determined using threshold-based (15%-85%) segmentation. Visual semiquantitative scoring in each lung segment was performed using Begic method. RHC hemodynamic parameters including pulmonary artery systolic pressure (PASP), pulmonary arterial diastolic pressure (PADP), mean pulmonary artery pressure (mPAP), pulmonary arteriolar wedge pressure (PAWP), pulmonary vessel resistance (PVR), cardiac output (CO), cardiac index (CI) were recorded. Spearman correlation analysis was used to evaluate the correlations between perfused lung volumes, visual scores and hemodynamic parameters.Results:There were significant correlations between perfused lung volumes (30%-70% threshold) and mPAP ( rs values: from -0.414 to -0.302, all P<0.05). Among them, perfused lung volumes under the threshold of 40% and 45% were moderately correlated with mPAP ( rs values: -0.414, -0.412, both P<0.05). Perfused lung volume (40% threshold) was moderately negatively correlated with PASP, PADP ( rs values: -0.402, -0.440, both P<0.05), and slightly negatively correlated with PVR ( rs=-0.352, P<0.05). Visual scores were slightly positively correlated with the PADP ( rs=0.311, P<0.05), while there was no correlation between visual scores and other RHC hemodynamic parameters ( rs values: from -0.201 to 0.275, all P>0.05). Conclusion:Perfused lung volumes based on threshold-based segmentation in lung perfusion SPECT/CT imaging can accurately reflect hemodynamic status and may provide useful information for severity assessment of CTEPH.
ABSTRACT
Objective:To compare the clinical utility of 18F-fibroblast activating protein inhibitor (FAPI)-42 and 18F-fluorodeoxyglucose (FDG) PET/CT imaging in newly diagnosed lung cancer patients. Methods:From May 2020 to September 2021, the images of 43 lung cancer patients (32 males, 11 females, age: 37-80 years) who pathologically confirmed and received 18F-FDG and 18F-FAPI-42 PET/CT within 2 weeks in the First Affiliated Hospital of Guangzhou Medical University were prospectively analyzed. The maximum standardized uptake value (SUV max) of 18F-FDG and 18F-FAPI-42 and the number of lesions detected by 2 imaging methods were compared by using paired t test and Wilcoxon rank sum test. Results:The 43 newly diagnosed lung cancer patients included 35 adenocarcinoma, 2 squamous cell carcinoma, 4 small cell lung cancer, and 2 high-grade neuroendocrine tumors. 18F-FAPI-42 had a very high tumor uptake (SUV max: 12.24±3.97) and lesion detection rate (positive rate: 100%(37/37)) in primary lung adenocarcinoma and squamous cell carcinoma. The uptake of 18F-FAPI-42 in lymph node (10.13±5.43), pleura (6.75(4.96, 8.58)) and bone lesion (7.18(4.33, 9.66)) were significantly higher than those of 18F-FDG (6.35±3.30, 2.69(1.81, 5.00), 4.38(2.96, 6.36); t=12.19, z values: 5.47, 5.79, all P<0.001). In lung adenocarcinoma and squamous cell carcinoma, although the uptake of 18F-FAPI-42 in brain metastases was significantly lower than that of 18F-FDG (0.72(0.15, 1.82) vs 6.53(4.65, 9.34); z=6.42, P<0.001), the tumor/background (T/B) ratio was significantly higher than that of 18F-FDG (3.54(1.15, 14.88) vs 0.96(0.77, 1.04); z=6.05, P<0.001). In lung adenocarcinoma and squamous cell carcinoma, the number of lesions detected by 18F-FAPI-42 PET/CT was significantly more than that of 18F-FDG (lymph node: 6.0(2.3, 11.5) vs 4.5(2.0, 10.8); brain: 2.0(1.0, 3.0) vs 0.0(0.0, 0.0); pleura: 6.0(2.8, 10.0) vs 4.0(0.8, 5.5); z values: 2.16, 3.10, 2.04, all P<0.05). However, in high-grade neuroendocrine tumors and small cell lung cancer, the SUV max of 18F-FAPI-42 in primary lesions (8.05±2.60), lymph node lesions (5.98±2.21) and brain lesions (0.44(0.13, 0.82)) were lower than those of 18F-FDG (16.28±5.17, 12.30±5.47, 4.94(4.84, 6.25); t values: 3.58, 7.52, z=3.06, all P<0.05). Conclusions:In lung adenocarcinoma and squamous cell carcinoma, 18F-FAPI-42 has a very high tumor uptake and lesion detection rate in primary tumor. In addition, compared with 18F-FDG PET/CT, 18F-FAPI-42 PET/CT shows clearer tumor contours and more lesions. Therefore, 18F-FAPI-42 is more suitable for preliminary staging of lung adenocarcinoma and squamous cell carcinoma than 18F-FDG, while the opposite is true in small cell lung cancer and high-grade neuroendocrine tumors.