Diagnosis Of Solitary Pulmonary Nodules Research Articles

The Value of 18F-FDG PET/CT Mathematical Prediction Model in Diagnosis of Solitary Pulmonary Nodules.

Purpose To establish an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) mathematical prediction model to improve the diagnosis of solitary pulmonary nodules (SPNs). Materials and Methods We retrospectively reviewed 177 consecutive patients who underwent 18F-FDG PET/CT for evaluation of SPNs. The mathematical model was established by logistic regression analysis. The diagnostic capabilities of the model were calculated, and the areas under the receiver operating characteristic curve (AUC) were compared with Mayo and VA model. Results The mathematical model was y = exp⁡(x)/[1 + exp⁡(x)], x = −7.363 + 0.079 × age + 1.900 × lobulation + 1.024 × vascular convergence + 1.530 × pleural retraction + 0.359 × the maximum of standardized uptake value (SUVmax). When the cut-off value was set at 0.56, the sensitivity, specificity, and accuracy of our model were 86.55%, 74.14%, and 81.4%, respectively. The area under the receiver operating characteristic curve (AUC) of our model was 0.903 (95% confidence interval (CI): 0.860 to 0.946). The AUC of our model was greater than that of the Mayo model, the VA model, and PET (P < 0.05) and has no difference with that of PET/CT (P > 0.05). Conclusion The mathematical predictive model has high accuracy in estimating the malignant probability of patients with SPNs.

P3.02-008 Non-Invasive Diagnosis of Solitary Pulmonary Nodules Using High-Throughput Targeted DNA Methylation Sequencing of Circulating Tumor DNA

It remains a great challenge to differentiate solitary pulmonary nodules which might cause excessive medical care and unnecessary psychological burden. Disadvantages of previous image-based or invasive methods call for better diagnostic tools.

Combination diagnosis of multi-slice spiral computed tomography and secretary phospholipase A2-IIa for solitary pulmonary nodules.

This study was aimed to compare the diagnostic value of multi-slice spiral computed tomography (CT) and secretary phospholipase A2-IIa (sPLA2-IIa) in differentiating between malignant and benign solitary pulmonary nodules (SPNs). A total of 223 patients with SPNs (91 patients with malignant SPNs and 132 patients with benign SPNs) were included from Weihai Central Hospital during October 2014 to December 2016. SPN diagnosis was confirmed in all patients using needle biopsy, surgery and bronchoscopy. The patients were managed with dynamic multi-slice CT scans, and their sPLA2-IIa levels were also detected. By selecting the area of interest of focus, the perfusion parameters of multi-slice CT targeting the focus were obtained. The levels of MTT, PS, BV, BF and sPLA2-IIa significantly increased with increasing severity of SPNs (P<.05). Notably, BV (area under the ROC curve [AUC]=0.915; 95%CI: 0.88-0.95; sensitivity=91.21%; specificity=78.79%) showed a higher potential to discriminate patients with malignant SPNs from those with benignSPNs than didBF(AUC=0.712; 95%CI: 0.65-0.78; sensitivity=72.50%; specificity=59.10%), PS (AUC=0.772; 95%CI: 0.71-0.84; sensitivity=65.93%; specificity=82.58%) and MTT (AUC=0.600; 95%CI: 0.52-0.68; sensitivity=52.75%; specificity=78.03%). Finally, the combined diagnostic value of BV and sPLA2-IIa was quite ideal (AUC=0.947; 95%CI: 0.92-0.97; sensitivity=85.70%; specificity=92.70%) for malignant and benign SPNs. The combined diagnostic value of BV and sPLA2-IIa appeared as a desirable detection method for malignant and benign SPNs.

Diagnosis of Solitary Pulmonary Nodules Using MRI: A Feasibility Study

Solitary pulmonary nodule (SPN) is explained as a separate, well-determined obscurity with the maximum size of 3cm which is enclosed by typical lung tissue and is not related to any other anomalies in the lung or adjacent lymph nodes. Among imaging modalities MRI has more benefits such as high spatial resolution and usage of nonionizing radiation, however, the efficacy of this imaging modality in lung nodules diagnosis has not been well established. Thus CT scan is considered a proper modality for the SPN diagnosis. The objective of this study was to evaluate the accuracy of MRI in the detection of SPNs which has verified by CT scan. The study was conducted as a prospective case-control study. 32 SPN patients whose disease confirmed by CT scan findings and 11 patient with normal CT scan were included in this study. Sensitivity, specificity, positive and negative predictive values of MRI were determined. The location and the size of pulmonary nodules as well as different MRI sequences were evaluated. Statistical analysis revealed that T1w sequences (27%) had the least diagnostic sensitivity, T2w images, and Fat-sat slices had 55% and 36% sensitivity respectively. Specificity of T1w, T2w, and Fat-sat images were 97%, 90% for the last two imaging sequences. According to the results, it can be concluded that although the specificity of different MRI sequences was ? 90%, low sensitivity and breath holding technique prevents its clinical routine usage for the suspected patients with SPN or early detection of pulmonary nodules in high-risk patients.

Endobronchial ultrasound transbronchial biopsy with guide-sheath for the diagnosis of solitary pulmonary nodules.

The aim of this study was to assess the usefulness of endobronchial ultrasound transbronchial biopsy with guide-sheath (EBUS-GS-TBB) for the diagnosis of solitary pulmonary nodules (SPNs). One hundred and eighty patients, who were diagnosed with SPNs and underwent an endobronchial ultrasound procedure. The diagnostic yield, safety and the associated factors were analyzed. Mean EBUS-GS procedure time was 14±8 min. The average number of biopsy specimens obtained in each SPNs was 5±1.2. One hundred and thirty-four SPNs were diagnosed by EBUS-GS-TBB and the diagnostic rate was 74.4 %. The diagnosis rate of malignancy was 83.3 %, while that of benign disease was 56.7 %. The most important factors that helped enhance EBUS-GS diagnostic accuracy included lesion diameter greater than 20mm, EBUS probe within the lesions and central lesions. No pneumothorax, hemoptysis or other serious complications occurred with the diagnostic procedures. EBUS-GS-TBB is a safe and effective method for diagnosing SPNs.

SOLITARY PULMONARY NODULES: EFFECTIVENESS OF DYNAMIC CT IN THE DIFFERENTIAL DIAGNOSIS

The differential diagnosis of solitary pulmonary nodules remains a challenge in oncology. Dynamic contrastenhanced CT is a potentially valuable tool capable of detecting malignancy. The purpose of the study was to evaluate the value of dynamic CT in the differential diagnosis of solitary pulmonary nodules. Material and methods. Fifty two patients with solitary pulmonary nodules underwent CT examination using a GE Optima CT660. The CT protocol included: 1) scan volume from the jugular notch to the end of the diaphragmatic dome; 2) location of the nodule in the lung; 3) scanning time for 30 sec, 1 min, 2 min, 4 min and 6 min following contrast agent injection. The image processing was carried out on an Advantage Workstation for Windows (AW4.5, GE Healthcare). The CT findings were verified by histology after CT-guided transthoracic biopsy of lung lesions and lung surgeries. Results. The sensitivity, specificity and accuracy of dynamic contract-enhanced CT were higher than those without dynamic CT (85, 95 and 92 % versus 71, 95 and 88 %, respectively).

P2.01-004 The Methylation Profiling of Multiple Tumor Suppressor Genes in Plasma Cell-Free DNA of Patients with NSCLC vs Benign Tumors

Effective discrimination between lung cancer and benign tumors is a common clinical problem in the differential diagnosis of solitary pulmonary nodules. While most solitary pulmonary nodules are benign, around 20% of cases represent an early stage lung cancer. The presence of cell-free DNA (cfDNA) in plasma of lung cancer patients demonstrates promising diagnostic implications and could be considered as an auxiliary tool in the differential diagnosis of solitary pulmonary nodules by evaluating cancer-specific biomarkers, such as hypermethylated tumor DNA fragments. We developed a simultaneous methylation profiling of 21 distinct tumor suppressor genes (TSGs) in plasma cfDNA using MS-MLPA assay. The methylation profiling of 21 TSGs in plasma cfDNA of 32 resectable NSCLC (I-IIIa) patients and 8 subjects with benign lung nodules (hamartoma, fibrosis, granuloma) was performed using optimized MS-MLPA assay. 25/32 (78%) NSCLC and 8/8 (100%) benign-nodule cfDNA samples presented at least one TSG methylation, however the number of hypermethylated TSGs was much higher in NSCLC group. APC (frequency 18% samples), MLH1 (18%), ATM (13.6%), DAPK1 (13.6%), HIC 1 (13.6%), and RARβ (9%) were the most frequently methylated genes in NSCLC, while TIMP3 (75%), MLH1 (25%) and TP73 (37.5%) – in benign patients. The optimized MS-MLPA assay allowed simultaneous detection of multiple methylated TSGs in plasma cfDNA. The MS-MLPA showed good performance in samples with diverse cfDNA concentrations suggesting that methylation detection rate depends on the methylated DNA content in a sample. The study is on-going. The groups are to be extended and other benign lung pathologies evaluated.

P1.05-009 Clinical Value of Circulating Tumor Cell in the Differential Diagnosis of Solitary Pulmonary Nodule

The diagnosis of lung cancer suffers from the lack of accurate, noninvasive and early diagnostic tests. Low-dose helical computed tomography (LDCT) identifies millions of solitary pulmonary nodules (SPN) annually, many of which are undiagnosed as either malignant or benign. When removed surgically, 18%-25% of the nodules are benign, which leads to unnecessary treatment procedures for surgeons, stress and panic for patients and waste of medical resources for government. Therefore, an accurate noninvasive test that can discriminate benign SPN from malignant is urgently needed. Circulating tumor cells (CTCs) are cells shed from either primary or secondary tumors that migrate into the circulatory system and exist at the early stage of cancer. In recent years, CTC has become the research hotspot because of its great significance in the early diagnosis of cancer, disease monitoring, prognosis evaluation and guiding individualized treatment. In this study, we evaluated the application value of CTC in the differential diagnosis of SPN. Peripheral blood samples were collected from 134 patients with solitary pulmonary nodule in Shanghai Chest Hospital from September 2013 to January 2015, including 80 patients with malignant nodule and 54 with benign nodule. CTC levels of the above subjects were detected by LT-PCR (ligand-targeted polymerase chain reaction, LT-PCR) assay, and serum CEA and CYFRA21-1 were detected by flow fluorescence assay. The CTC levels of malignant SPN patients were significantly higher than that of benign SPN patients (P<0.001). The area under the Receiver Operating Characteristic (ROC) curves of CTC and CEA were 0.817(95% CI: 0.743∼0.891) and 0.613(95% CI: 0.508∼0.718) respectively, while the CYFRA21-1 had no significant meaning in the differential diagnosis of SPN. The positive and negative predictive value (PPV and NPV) in differential diagnosis of SPN for CTC were 89% and 74%. Then the patients were divided into three groups according to the nodule diameter to evaluate the diagnostic value of CTC in SPN with different size. For SPN with diameter less than 8 mm, the PPV and NPV of CTC were 86% and 57%; For SPN with diameter between 8 mm and 20 mm, the PPV and NPV of CTC were 88% and 81%; For SPN with diameter greater than 20 mm, the PPV and NPV of CTC were 92% and 68%. Compared with traditional tumor marker, CTC detection could provide more clinical value in differential diagnosis of solitary pulmonary nodule.

Solitary pulmonary nodule evaluation in regions endemic for infectious diseases: Do regional variations impact the effectiveness of fluorodeoxyglucose positron emission tomography/computed tomography.

Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a preferred imaging modality for the evaluation of solitary pulmonary nodule (SPN), particularly in the developed world. Since FDG can concentrate in infective/inflammatory lesions, the diagnostic utility of FDG-PET can be questioned, particularly in regions endemic for infectious decisions. To evaluate the accuracy of FDG-PET/CT in evaluation of SPNs in a population endemic for infectious disease and to assess if regional variations have an impact on its effectiveness. All patients who underwent an FDG/PET-CT with a clinico-radiological diagnosis of SPN categorized as indeterminate were included. Based on a maximum standardized uptake values (SUVmax) cut-off of 2.5, lesions were classified as benign (<2.5) or malignant (>2.5) and compared with gold standard histopathology. The diagnostic accuracy of PET-CT to detect malignancy was calculated. On the basis of final histopathology, lesions were grouped as (a) malignant nodules (b) infective/granulomatous nodules with a specific diagnosis and (c) nonspecific inflammatory nodules. The SUVmaxbetween these groups was compared using nonparametric statistical tests. A total of 191 patients (129 males, 62 females) with a median age of 64 years (range: 36-83) were included. Totally, 144 nodules (75.3%) were malignant and 47 were benign (24.7%). Adenocarcinoma (n = 84) was the most common malignancy. Tuberculosis (n = 16) and nonspecific infections (n = 24) were the two most common benign pathologies. There was a significant overlap in the metabolic uptake of malignant (median SUVmax-11.2, range: 3.3-34.6) and tuberculous nodules (median SUVmax-10.3, range: 2.7-22.5) with no statistically difference between their SUVmaxvalues (P = 0.43). The false-positive rate was 65.2% and the false-negative rate was 5.5%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET/CT for detecting malignancy were 94.4%, 34.7%, 81.9%, 66.6%, and 79.5%, respectively. Though FDG-PET scans show a very high sensitivity for malignant nodules, it has a high false-positive rate and reduced specificity when characterizing SPNs in an infectious endemic region. Physicians must be aware of this limitation in the workup of lung nodules, and regional variations must be considered before further management decisions are taken.

PUB020 Same Day CT for the Bronchoscopic Diagnosis of SPN May Decrease Unnecessary Procedures in Suspected Lung Cancer Patients

Bronchoscopy is commonly used for the diagnosis of solitary pulmonary nodules discovered on CT scanning of the chest. Initial imaging is often completed well before the date of a scheduled test, with repeat imaging generally not repeated prior to the diagnostic procedure. We report a series of resolving nodules seen on chest CT performed the day of electromagnetic navigational bronchoscopy guided biopsy resulting in cancellation of the procedure. A prospective case series for patients undergoing navigational bronchoscopy using a new technology requiring same day CT imaging at a single quaternary care center. Patients undergoing navigational bronchoscopy found to have a decrease in the size or resolution of their nodule leading to the cancellation of their case were included. Included patients had demographic data, lung cancer risk factors as well as pre and day of CT imaging collected. During the study period, 106 patients were scheduled for navigational bronchoscopy for the diagnosis of a pulmonary nodule. Of the 106 patients scheduled 7 (6.6%) had a decrease in the size of/or resolution of their nodule leading to the cancellation of their procedure. The average time from initial CT prompting referral for bronchoscopy to the day of procedure scan for those cancelled was 53 days. Time from initial imaging to day of procedure is variable, occasionally allowing enough time for nodules to resolve obviating the need for biopsy. Although bronchoscopy is a safe and well tolerated procedure, same day imaging may decrease unnecessary procedural risk.

Comparison of Positron Emission Tomography Using 2-[18F]-fluoro-2-deoxy-D-glucose and 3-deoxy-3-[18F]-fluorothymidine in Lung Cancer Imaging.

Background:The detection of solitary pulmonary nodules (SPNs) that may potentially develop into a malignant lesion is essential for early clinical interventions. However, grading classification based on computed tomography (CT) imaging results remains a significant challenge. The 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/CT imaging produces both false-positive and false-negative findings for the diagnosis of SPNs. In this study, we compared 18F-FDG and 3-deoxy-3-[18F]-fluorothymidine (18F-FLT) in lung cancer PET/CT imaging.Methods:The binding ratios of the two tracers to A549 lung cancer cells were calculated. The mouse lung cancer model was established (n = 12), and micro-PET/CT analysis using the two tracers was performed. Images using the two tracers were collected from 55 lung cancer patients with SPNs. The correlation among the cell-tracer binding ratios, standardized uptake values (SUVs), and Ki-67 proliferation marker expression were investigated.Results:The cell-tracer binding ratio for the A549 cells using the 18F-FDG was greater than the ratio using 18F-FLT (P < 0.05). The Ki-67 expression showed a significant positive correlation with the 18F-FLT binding ratio (r = 0.824, P < 0.01). The tumor-to-nontumor uptake ratio of 18F-FDG imaging in xenografts was higher than that of 18F-FLT imaging. The diagnostic sensitivity, specificity, and the accuracy of 18F-FDG for lung cancer were 89%, 67%, and 73%, respectively. Moreover, the diagnostic sensitivity, specificity, and the accuracy of 18F-FLT for lung cancer were 71%, 79%, and 76%, respectively. There was an obvious positive correlation between the lung cancer Ki-67 expression and the mean maximum SUV of 18F-FDG and 18F-FLT (r = 0.658, P < 0.05 and r = 0.724, P < 0.01, respectively).Conclusions:The 18F-FDG uptake ratio is higher than that of 18F-FLT in A549 cells at the cellular level. 18F-FLT imaging might be superior for the quantitative diagnosis of lung tumor tissue and could distinguish lung cancer nodules from other SPNs.

Clinical value of circulating tumor cell in the differential diagnosis of solitary pulmonary nodule

Objective To evaluate the application value of circulating tumor cell (CTC) in the differential diagnosis of solitary pulmonary nodule (SPN). Methods Peripheral blood samples were collected from 134 patients with solitary pulmonary nodule in Shanghai Chest Hospital from September 2013 to January 2015, including 80 patients with malignant nodule and 54 with benign nodule. CTC levels of the above subjects were detected by ligand-targeted polymerase chain reaction (LT-PCR) assay, and serum carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA21-1) were detected by flow fluorescence assay. Results By Mann-Whitney U Test, the CTC levels of malignant SPN patients [11.06(8.77-14.41)units/3 ml] were significantly higher than those of benign SPN patients [6.65(4.49-7.84)units/3 ml] (Z=-6.217, P<0.001). The sensitivity and specificity of differential diagnosis of SPN for CTC were 80%(64/80)and 85%(46/54)respectively. According to the diameter of SPN, the patients were divided into three groups to evaluate the diagnostic value of CTC in SPN with different size. For SPN with diameter less than 8 mm, the sensitivity and specificity of CTC were 6/9 and 4/5 respectively. For SPN with diameter between 8 mm and 20 mm, the sensitivity and specificity of CTC were 83%(35/42) and 85%(29/34). For SPN with diameter greater than 20 mm, the sensitivity and specificity of CTC were 79% (23/29)and 13/15. Conclusion Comparing with the traditional tumor markers, CTC could provide more clinical value in the differential diagnosis of solitary pulmonary nodule. (Chin J Lab Med, 2016, 39: 941-945) Key words: Solitary pulmonary nodule; Neoplastic cells, circulating; Diagnosis, differential

Diagnosis of solitary pulmonary nodules and patients follow-up strategy

Solitary pulmonary nodule is the common clinical problem. Following the detection of solitary nodules practitioner first face the question of the probability of malignancy and the future strategy and tactics of the patient management. The report highlights the issues of differential diagnosis of solitary nodules and modern standards of management of these patients, including issues of their follow-up care. The importance of a multidisciplinary approach to this problem is emphasized. Strategy for the management of patients with solitary nodules include: (1) the computed tomography performance, its comparing with previous data; (2) an assessment of the margin, size, calcification type, solitary nodule type (solid, subsolid); (3) the risk of malignancy assessment. Further actions can be performed according to algorithms: nodule ≤8 mm; nodule &gt;8 mm. According to screening tests for the early detection of lung cancer in smokers at high risk for development of malignant tumors, solitary nodules are found in 50% of cases. When choosing a strategy it is necessary to inform the patient about all the positives and negatives of follow-up care by means of computed tomography. Its main goal is to secure patient with benign nodules against unwanted invasive procedures, especially if there is no need for treatment. This advantage is put on one side of the scale, and on the second - the risk of delayed diagnosis of cancer, and excessive exposure to radiation. In light of the above all the patients with solitary nodules of undefined etiology should be referred to a specialized pulmonary center for multidisciplinary experts evaluating - pulmonologists, thoracic surgeons, pathologists and radiology specialists, which allows to develop the most optimal strategy for these patients.

Differential diagnosis of solitary pulmonary nodules with dual-source spiral computed tomography.

The aim of the present study was to analyze the value of applying dual-source 64-layer spiral computed tomography (CT) in the differential diagnosis of solitary pulmonary nodules (SPNs). Mediastinal windows from 45 cases were selected to study SPNs (maximum diameter, ≤3 cm), and the pathological nature of lesions was determined by clinical and pathological diagnosis. Conventional 64-layer spiral CT scanning, local enhancement and 3D recombination technologies were used to determine the occurrence rate, lesion diameter, degree of enhancement, lobular sign, spicule sign, pleural indentation sign, vessel convergence sign and bronchus sign. The final diagnoses indicated 34 cases of malignant SPNs (75.6%) and 11 benign cases (24.4%). When the nodule diameter in the malignant group was compared with that of the benign group, the difference was not statistically significant (P>0.05). Nodules in the malignant group showed inhomogeneous enhancement while nodules in the benign group showed homogeneous enhancement. The enhanced CT values in the malignant group were higher than those in the benign group, and the difference was statistically significant (P<0.05). The proportion of nodules with lobular sign in the malignant group was significantly higher than that in the benign group (P<0.05). The proportion of nodules with calcification, vessel convergence sign and bronchus sign in the malignant group were significantly higher than those in the benign group, and the differences were statistically significant (P<0.05). A comparison of vacuole sign, pleural indentation sign, spiculate protuberance and fat occurrence between the two groups yielded no statistically significant differences (P>0.05). The sensitivity of CT enhancement was 85.6%, specificity was 79.6%, positive predicated value was 92.3%, and the negative predicted value was 85.2%. In conclusion, SPNs diagnosed by CT enhancement manifested with enhancement degree, lobular sign, calcification, vessel convergence sign and bronchus sign with high diagnostic accuracy.

Value of gemstone spectral CT imaging in diagnosis of solitary pulmonary nodule

To observe the diagnostic efficiency of gemstone spectral CT imaging in diagnosis of solitary pulmonary nodule (SPN). A total of 114 patients with SPN proved by pathology (from the First Affiliated Hospital of Zhengzhou University and 13 cooperative hospitals) underwent spectral CT from July 2014 to July 2015.All the patients were divided into malignant group(63 cases), inflammatory group(32 cases) and tuberculosis group(19 cases) .Iodine concentration(IC), normalized iodine concentration(NIC) and slope rate of spectral curve(40-80 keV) in both arterial and venous phase were measured and calculated.The one-way ANOVA and LSD were used to analyze parameters among 3 groups.ROC curves were taken to calculate the diagnostic efficiency and the diagnostic sensitivity and specificity . IC, NIC and slope rate of spectral curve had statistically significant differences in both phases (all P<0.05). The malignant group was the highest, and the tuberculosis group was the lowest(all P<0.05). When NIC(venous phase)>0.31, NIC>0.28, NIC>0.21, the sensitivity of diagnosing malignant and inflammatory SPN, malignant and tuberculosis SPN, inflammatory and tuberculosis SPN were respectively 81.0%, 85.7%, 84.4%, and the specificity of them were 71.9%, 94.7%, 84.2%, respectively. Spectral CT imaging is helpful to diagnosis of SPN, and venous phase NIC can get high sensitivity and specificity for qualitative diagnosis of SPN.

Distribution of Solid Solitary Pulmonary Nodules within the Lungs on Computed Tomography: A Review of 208 Consecutive Lesions of Biopsy-Proven Nature.

SummaryBackgroundThe solitary pulmonary nodule (SPN) is a common radiologic abnormality on chest x-rays or computed tomography (CT) scans of the lungs. The differential diagnosis of SPNs is particularly wide as it includes a multitude of benign as well as malignant entities. Nodule location within the lungs has been proposed as a predictive feature in the literature. This study aims at illustrating the distribution within the lungs of a large current series of consecutive SPNs according to their histological subtype, which was definitely proved at core biopsy.Material/MethodsTwo hundred-eight SPNs referred to our center for characterization were reviewed in this single-centre retrospective study. Histological subtypes were defined following the IASLC/ATS/ERS and WHO (2004) histological classification.ResultsThis study provides evidence with respect to the prevalence of adenocarcinomas and other non-neuroendocrine primary lung cancer types in the right upper lobe. It also provides new evidence with respect to the prevalence of carcinoid tumors in the middle and right lower lobe, with a tendency to occur in the central lung parenchyma.ConclusionsThis work updates existing knowledge of solid SPNs location within the lungs by providing a current picture of SPN distribution according to their nature.

Solitary pulmonary nodule and (18)F-FDG PET/CT. Part 2: accuracy, cost-effectiveness, and current recommendations.

A solitary pulmonary nodule is a common, often incidental, radiographic finding. The investigation and differential diagnosis of solitary pulmonary nodules remain complex, because there are overlaps between the characteristics of benign and malignant processes. There are currently many strategies for evaluating solitary pulmonary nodules. The main objective is to identify benign lesions, in order to avoid exposing patients to the risks of invasive methods, and to detect cases of lung cancer accurately, in order to avoid delaying potentially curative treatment. The focus of this study was to review the evaluation of solitary pulmonary nodules, to discuss the current role of 18F-fluorodeoxyglucose positron-emission tomography, addressing its accuracy and cost-effectiveness, and to detail the current recommendations for the examination in this scenario.

Low-dose volume perfusion computed tomography (VPCT) for diagnosis of solitary pulmonary nodules

ObjectiveTo characterize solitary pulmonary nodules (SPN) in terms of perfusion parameters using low-dose volume perfusion computed tomography (VPCT) and two different calculation methods, compare their results, look for interobserver agreement of measurements and investigate the feasibility of low-dose VPCT. Materials and methodsThis study was approved by the local Institutional Review Board and all patients provided written informed consent. Seventy-one patients (mean age 60.8 years ±9.6) with solitary pulmonary nodules were enrolled. Low-dose VPCT was performed for 38.63s covering the involved lung (70kV, 120mAs, 22 consecutive volume measurements, 50mL iodinated contrast, flow rate 4mL/s). Mean blood flow (BF), blood volume (BV) and k-trans were determined both with the maximum slope+Patlak vs. deconvolution method. Additionally, the difference of VPCT parameters between different type lesions and normal tissue was analyzed. Interobserver agreement for all perfusion parameters was calculated using intraclass correlation coefficients (ICC). The effective radiation dose of the VPCT and the total CT scan protocol were recorded. All CT findings were histologically confirmed by surgical intervention. ResultsThe mean lesion size was 18.6mm. Interobserver agreement measure with ICC shows high agreement between the measurements (κ=0.85). The effective radiation dose of the VPCT was 9.3mSv. The mean perfusion values for BF, BV and k-trans of 120.6mL/100g tissue/’, 11.6mL/100g tissue/’, and 18.5mL/100g tissue/’ for the deconvolution method, and 50.1mL/100g tissue/’, 11.6mL/100g tissue/’ and 24.3mL/100g tissue/’ for the maximum slope+Patlak method, which were significantly higher than those of normal muscle (20.7mL/100g tissue/’, 2.6mL/100g tissue/’, and 7.6mL/100g tissue/’ for the deconvolution method and 10.9mL/100g tissue/’, 3.1mL/100g tissue/’ and 8.1mL/100g tissue/’ for the maximum slope method). The best overall correlation between calculation methods was achieved for measurements of BF. ConclusionThe low-dose volume perfusion CT of the solitary pulmonary nodules can effectively reduce the radiation dose and non-invasively assess perfusion of SPN within the entire lesion volume.

Plasma cell-free DNA levels and integrity in patients with chest radiological findings: NSCLC versus benign lung nodules

Effective discrimination between lung cancer and benign tumours is a common clinical problem in the differential diagnosis of solitary pulmonary nodules. The analysis of cell-free DNA (cfDNA) in blood may greatly aid the early detection of lung cancer by evaluating cancer-related alterations. The plasma cfDNA levels and integrity were analysed in 65 non-small cell lung cancer (NSCLC) patients, 28 subjects with benign lung tumours, and 16 healthy controls using real-time PCR. The NSCLC patients demonstrated significantly higher mean plasma cfDNA levels compared with those with benign tumours (P = 0.0009) and healthy controls (P < 0.0001). The plasma cfDNA integrity in healthy individuals was significantly different than that found in patients with NSCLC or benign lung tumours (P < 0.0003). In ROC curve analysis, plasma cfDNA levels >2.8 ng/ml provided 86.4% sensitivity and 61.4% specificity in discriminating NSCLC from benign lung pathologies and healthy controls. cfDNA integrity showed better discriminatory power (91% sensitivity, 68.2% specificity). These data demonstrate that plasma cfDNA concentration and integrity analyses can significantly differentiate between NSCLC and benign lung tumours. The diagnostic capacity of the quantitative cfDNA assay is comparable to the values presented by conventional imaging modalities used in clinical practice.

Novel Methods of Intraoperative Localization and Margin Assessment of Pulmonary Nodules

Lung cancer screening has lead to frequent diagnosis of solitary pulmonary nodules, many of which require surgical biopsy for diagnosis and intervention. Subcentimeter and central nodules are particularly difficult to visualize or palpate during surgery, thus nodule localization can be a difficult problem for the thoracic surgeon. Although minimally invasive techniques including transthoracic computed tomography and bronchoscopic-guided biopsy may establish a diagnosis, these methods do not help locate nodules during surgery and can lead to inadequate tissue sampling. Therefore, surgical biopsy is often required for diagnosis and management of solitary pulmonary nodules. Additionally, after an excision, intraoperative margin assessment is important to prevent local recurrence. This is important for bronchial margins following lobectomy or parenchymal margins following sublobar resection. First, we examine methods of preoperative lesion marking, including wire placement, dye marking, ultrasound, fluoroscopy, and molecular imaging. Second, we describe the current state of the art in intraoperative margin assessment techniques.