Comparison of Spectral and Perfusion Computed Tomography Imaging in the Differential Diagnosis of Peripheral Lung Cancer and Focal Organizing Pneumonia.

Liangna Deng,Mengyuan Jing,Xiaoqiang Lin,Guojin Zhang,Bin Zhang,Tao Han,Junlin Zhou

doi:10.3389/fonc.2021.690254

Abstract

ObjectiveTo investigate the spectral and perfusion computed tomography (CT) findings of peripheral lung cancer (PLC) and focal organizing pneumonia (FOP) and to compare the accuracy of spectral and perfusion CT imaging in distinguishing PLC from FOP.Materials and MethodsPatients who were suspected of having lung tumor and underwent “one-stop” chest spectral and perfusion CT, with their diagnosis confirmed pathologically, were prospectively enrolled from September 2020 to March 2021. Patients who were suspected of having lung tumor and underwent “one-stop” chest spectral and perfusion CT, with their diagnosis confirmed pathologically, were prospectively enrolled from September 2020 to March 2021. A total of 57 and 35 patients with PLC and FOP were included, respectively. Spectral parameters (CT40keV, CT70keV, CT100keV, iodine concentration [IC], water concentration [WC], and effective atomic number [Zeff]) of the lesions in the arterial and venous phases were measured in both groups. The slope of the spectral curve (K70keV) was calculated. The perfusion parameters, including blood volume (BV), blood flow (BF), mean transit time (MTT), and permeability surface (PS), were measured simultaneously in both groups. The differences in the spectral and perfusion parameters between the groups were examined. Receiver operating characteristic (ROC) curves were generated to calculate and compare the area under the curve (AUC), sensitivity, specificity, and accuracy of both sets of parameters in both groups.ResultsThe patients’ demographic and clinical characteristics were similar in both groups (P > 0.05). In the arterial and venous phases, the values of spectral parameters (CT40keV, CT70keV, spectral curve K70keV, IC, and Zeff) were greater in the FOP group than in the PLC group (P < 0.05). In contrast, the values of the perfusion parameters (BV, BF, MTT, and PS) were smaller in the FOP group than in the PLC group (P < 0.05). The AUC of the combination of the spectral parameters was larger than that of the perfusion parameters. For the former imaging method, the AUC, sensitivity, and specificity were 0.89 (95% confidence interval [CI]: 0.82–0.96), 0.86, and 0.83, respectively. For the latter imaging method, the AUC, sensitivity, and specificity were 0.80 (95% CI: 0.70–0.90), 0.71, and 0.83, respectively. There was no significant difference in AUC between the two imaging methods (P > 0.05).ConclusionSpectral and perfusion CT both has the capability to differentiate PLC and FOP. However, compared to perfusion CT imaging, spectral CT imaging has higher diagnostic efficiency in distinguishing them.

Highlights

Focal organizing pneumonia (FOP) is a subtype of organizing pneumonia, accounting for approximately 10–15% of organizing pneumonia cases [1]
Yu et al [14] evaluated the use of spectral computed tomography (CT) to image malignant tumors and inflammatory masses; they found that the area under the curve (AUC) of the CT value, slope of spectral curve, and normalized iodine concentration (IC) values were all greater than 80%, and the sensitivity and specificity values of the venous phase with normalized IC were 86% and
Our findings suggest that both spectral and perfusion CT imaging are associated with diagnostic efficiency at distinguishing peripheral lung cancer (PLC) from FOP

Summary

Introduction

Focal organizing pneumonia (FOP) is a subtype of organizing pneumonia, accounting for approximately 10–15% of organizing pneumonia cases [1]. It often presents as a solitary nodule or mass on chest computed tomography (CT) and is associated with atypical symptoms and imaging findings that overlap with those of peripheral lung cancer (PLC) [2]. 18F-deoxyglucose positron emission tomography can provide more information about the functional metabolism of the lesion, but its use in clinical practice is limited due to its high cost and excessive radiation dose [5, 6]. Yu et al [14] evaluated the use of spectral CT to image malignant tumors and inflammatory masses; they found that the area under the curve (AUC) of the CT value, slope of spectral curve, and normalized iodine concentration (IC) values were all greater than 80%, and the sensitivity and specificity values of the venous phase with normalized IC were 86% and

Methods

Results

Conclusion