Characterization of the Solitary Pulmonary Nodule: ¹⁸F-FDG PET Versus Nodule-Enhancement CT

Abstract

OBJECTIVE. The purpose of this study was to directly compare nodule-enhancement CT and 18 F-FDG PET in the characterization of indeterminate solitary pulmonary nodules (SPNs) greater than 7 mm in size. MATERIALS AND METHODS.Examinations from patients undergoing both noduleenhancement CT and 18 F-FDG PET to characterize the same indeterminate SPN were reviewed. For nodule-enhancement CT, an SPN was considered malignant when it showed an unenhanced to peak contrast-enhanced increase in attenuation greater than 15 H. Fluourine-18-FDG PET studies were blindly reinterpreted by two qualified nuclear radiologists. SPNs qualitatively showing hypermetabolic activity greater than the mediastinal blood pool were interpreted as malignant. These interpretations were compared with the original prospective clinical readings and to semiquantitative standardized uptake value (SUV) analysis. Results were compared with pathologic and clinical follow-up.RESULTS. Forty-two pulmonary nodules were examined. Twenty-five (60%) were malignant, and 17 (40%) were benign. Nodule-enhancement CT was positive in all 25 malignant nodules and in 12 benign nodules, with sensitivity and specificity of 100% and 29%, respectively, and with a positive predictive value (PPV) and negative predictive value (NPV) of 68% and 100%, respectively. Qualitative 18 F-FDG PET interpretations were positive in 24 of the 25 malignant nodules and in four benign nodules. Fluourine-18-FDG PET was considered negative in one malignant nodule and in 13 of the 17 benign nodules. This correlates with a sensitivity and specificity of 96% and 76%, respectively, and with a PPV and NPV of 86% and 93%, respectively. Original prospective 18 F-FDG PET and semiquantitative SUV analysis showed sensitivity, specificity, PPV, and NPV of 88%, 76%, 85%, and 81% and 84%, 82%, 88%, and 78%, respectively.CONCLUSION. Due to its much higher specificity and only slightly reduced sensitivity, 18 F-FDG PET is preferable to nodule-enhancement CT in evaluating indeterminate pulmonary nodules. However, nodule-enhancement CT remains useful due to its high NPV, convenience, and lower cost. Qualitative 18 F-FDG PET interpretation provided the best balance of sensitivity and specificity when compared with original prospective interpretation or SUV analysis.

Pulmonary hamartoma with low FDG uptake: A case report

“…When opacity was detected on his chest roentgenogram (see Figure 1) chest CT was performed. On chest CT a heterogeneous pleura based solid lesion with minimal lobulated margins was seen on the anterior segment of the upper lobe of the right lung and a 5 mm parenchymal nodule on the superior segment of the lower lobe of right lung (see Figure 2,3). In accordance with these findings bronchoscopy and PET was performed to the patient.…”

“…It is mostly asymptomatic and show no FDG uptake on PET [1,2] . It is assumed to carry low risk for malignant transformation [3] . In addition; when diagnosed radiologically, hamartomas usually are being followed up clinically and radiologically.…”

Concurrent Lung Cancer in Non-Tuberculous Mycobacteriosis: Case Report

“…However, prominent spiculations of a lesion in the right S8 were suspicious for concomitant lung cancer and prompted us to perform another biopsy. Several radiological features may be useful in discriminating between benign and malignant lung lesions [10]. These features may be applicable when concurrent lung cancer is suspected in patients with mycobacteriosis.…”

Informatics and Computerized Tomography Aiding Detection and Diagnosis of Solitary Lung Cancer

“…The computerized tomography with contrast injection is based on the fact that the vascularization of the malignant nodule is much more prominent than that of the benign one, especially in its central portion, occurrence demonstrated in immunohistochemistry techniques with the use of antibodies anti-factor VIII. Made under standardization, the method featured by Swensen and partners, in 1996, showed, with a cutoff point of 20 Hounsfield Units, a sensibility of 98%, a specificity of 73% and an accuracy of 85% (Christensen et al, 2006). Presently, in a general manner, we consider that a raise of more than 15 to 25 Hounsfield Units (HU), after a contrast injection in standardized conditions to enable comparison, suggests malignancy, but some benign conditions, inflammatory, such as tuberculous granuloma and cryptogenic pneumonia, can also raise the radiologic intensity (Jeong et al, 2005).…”

“…Lately, more value has been given to the impregnation curve (wash-in) and disimpregnation (wash-out) of contrast as a way to detail and help distinguishing the benign nodules from the malignant one. In practical terms, the absence of impregnation is the most useful dynamic feature, because it decreases significantly the possibility of malignancy, having elevated negative predictive value (Christensen et al, 2006). These conclusions are relativized in nodules smaller than 1 cm.…”