Evaluation Of Solitary Pulmonary Nodules Research Articles

Evaluation of solitary pulmonary nodules

Evaluation of solitary pulmonary nodules

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of solitary pulmonary nodule: a scoping review

Background: The role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in the surgical approach of solitary pulmonary nodule (SPN) is still debated, as the increased metabolic avidity of the lesion was not a sure sign of malignancy. The purpose of this study was to evaluate the effectiveness of 18F-FDG-PET/CT in the characterization of SPN based on the analysis of the most recent data in the literature.

Deep Learning-Based Digitally Reconstructed Tomography of the Chest in the Evaluation of Solitary Pulmonary Nodules: A Feasibility Study.

Computed tomography (CT) is preferred for evaluating solitary pulmonary nodules (SPNs) but access or availability may be lacking, in addition, overlapping anatomy can hinder detection of SPNs on chest radiographs. We developed and evaluated the clinical feasibility of a deep learning algorithm to generate digitally reconstructed tomography (DRT) images of the chest from digitally reconstructed frontal and lateral radiographs (DRRs) and use them to detect SPNs. This single-institution retrospective study included 637 patients with noncontrast helical CT of the chest (mean age 68 years, median age 69 years, standard deviation 11.7 years; 355 women) between 11/2012 and 12/2020, with SPNs measuring 10-30 mm. A deep learning model was trained on 562 patients, validated on 60 patients, and tested on the remaining 15 patients. Diagnostic performance (SPN detection) from planar radiography (DRRs and CT scanograms, PR) alone or with DRT was evaluated by two radiologists in an independent blinded fashion. The quality of the DRT SPN image in terms of nodule size and location, morphology, and opacity was also evaluated, and compared to the ground-truth CT images RESULTS: Diagnostic performance was higher from DRT plus PR than from PR alone (area under the receiver operating characteristic curve 0.95-0.98 versus 0.80-0.85; p < 0.05). DRT plus PR enabled diagnosis of SPNs in 11 more patients than PR alone. Interobserver agreement was 0.82 for DRT plus PR and 0.89 for PR alone; and interobserver agreement for size and location, morphology, and opacity of the DRT SPN was 0.94, 0.68, and 0.38, respectively. For SPN detection, DRT plus PR showed better diagnostic performance than PR alone. Deep learning can be used to generate DRT images and improve detection of SPNs.

Dual Energy Technique Adds Value to Solitary Pulmonary Nodule Analysis with Dynamic Contrast-Enhanced CT: A 100 Nodule Experience

A highly sensitive test for evaluation of solitary pulmonary nodules (SPN) involves a 5-phase, contrast enhanced CT evaluation which can be fraught with technical error. The goal of this study is to determine if qualitative evaluation of iodine maps with dual energy CT (DECT) can add value to SPN evaluation.100 patients had their SPN evaluated with traditional quantitative analysis and qualitative evaluation with iodine maps generated from DECT data acquired at 80 kVp and 140 kVp. Quantitative analysis served as the gold standard. Quantitative analysis was performed at 1, 2, 3, and 4 minutes. Qualitative Iodine maps analysis was performed at 1 and 2 minutes. Sensitivity and specificity were 63% and 95%, and 73% and 91%, respectively, at 1 and 2 minutes. Combined analysis resulted in sensitivity of 67% and specificity of 94%. Six of 7 false negatives on combined analysis were stable for 2 years and the seventh was lost to follow up after 1 year. Of 5 false positives on combined analysis; 2 were due to 'bleed-through of calcium' on iodine maps, 2 were positive on 3 and 4-minute quantitative analysis with one biopsy-proven adenocarcinoma. Qualitative analysis of Iodine maps generated using DECT data can be easily performed and may provide more effective evaluation of the solitary pulmonary nodule when combined with traditional analysis. This method warrants further investigation with larger patient populations, comparison with PET-CT, and evaluation of outcomes including long-term nodule stability and tissue diagnosis.

Solitary Pulmonary Nodule Evaluation: Pearls and Pitfalls

Lung nodules are frequently encountered while interpreting chest CTs and are challenging to detect, characterize, and manage given they can represent both benign or malignant etiologies. An understanding of features associated with malignancy and causes of interpretive pitfalls is helpful to avoid misdiagnoses. This review addresses pertinent topics related to the etiologies for missed lung nodules on radiography and CT. Additionally, CT imaging technical pitfalls and challenges in addition to issues in the evaluation of nodule morphology, attenuation, and size will be discussed. Nodule management guidelines will be addressed as well as recent investigations that further our understanding of lung nodules.

Strategies for the Management of Solitary Pulmonary Nodules: A Survey of Patient Preferences

BackgroundGuideline-based strategies for evaluation of solitary pulmonary nodules are tailored to the likelihood of malignancy. Surveillance, biopsy, and resection are all reasonable approaches in fit individuals when the likelihood of malignancy is intermediate. Given the paucity of data demonstrating superior outcomes and important trade-offs among strategies, guidelines emphasize the importance of eliciting patient preferences and engaging in shared decision making; however, there is little literature on what patient preferences actually are. MethodsThis study conducted a cross-sectional, interview-administered questionnaire survey in 100 adults recruited from a metropolitan teaching hospital (The Royal Melbourne Hospital, Parkville, Victoria, Australia). The questionnaire used a hypothetical scenario designed to elicit patient preferences for different management strategies of solitary pulmonary nodules with a probability of malignancy between 10% and 70%. ResultsThe mean age of participants was 62 years (range, 45 to 80 years), 56% were male, and 94% were current smokers or ex-smokers. Ninety-four percent completed all questions. At 10% probability of malignancy, 36.3% preferred surveillance, 42.4% preferred needle biopsy, and 21.2% preferred surgical resection. Preference for surgical resection increased to 53.5% and 86.2% when the probability of malignancy was 30% and 70%, respectively. Changes in the diagnostic yield of computed tomography biopsy significantly altered preferences when the probability of malignancy was 10% or 30%. ConclusionsThe majority of participants surveyed expressed a preference for some type of biopsy over observation at all levels of solitary pulmonary nodule probability of malignancy evaluated. In an era of increasing solitary pulmonary nodule detection and patient-centered care, if confirmed in broader studies, these findings have considerable implications for processes of care and resource allocation.

Pitfalls in Interpretation of PET/CT in the Chest

Whole body positron emission tomography (PET)/computed tomography (CT) imaging with [18F]-fluoro-2-deoxy-D-glucose (FDG) is widely used in oncologic imaging. In the chest, common PET/CT applications include the evaluation of solitary pulmonary nodules, cancer staging, assessment of response to therapy, and detection of residual or recurrent disease. Knowledge of the technical artifacts and potential pitfalls that radiologists may encounter in the interpretation of PET/CT in the thorax is important to avoid misinterpretation and optimize patient management. This article will review pitfalls in the interpretation of PET/CT in the chest related to technical factors, physiologic uptake, false positive findings, false negative findings, and iatrogenic conditions.

Role of Computed Tomography-guided Biopsies in the Era of Electromagnetic Navigational Bronchoscopy: A Retrospective Study of Factors Predicting Diagnostic Yield in Electromagnetic Navigational Bronchoscopy and Computed Tomography Biopsies.

Objectives:Over 25% of the high-risk population screened for lung cancer have an abnormal computed tomography (CT) scan. Conventionally, these lesions have been biopsied with CT guidance with a high diagnostic yield. Electromagnetic navigational bronchoscopy (ENB) with transbronchial biopsy has emerged as a technology that improves the diagnostic sensitivity of conventional bronchoscopic biopsy. It has been used to biopsy lung lesions, due to the low risk of pneumothorax. It is, however, a new technology that is expensive and its role in the diagnosis of the solitary pulmonary nodule (SPN) is yet to be determined. The purpose of this study was to evaluate the diagnostic yield of CT-guided biopsy (CTB) following non-diagnostic ENB biopsy and identify characteristics of the lesion that predicts a low diagnostic yield with ENB, to ensure appropriate use of ENB in the evaluation of SPN.Materials and Methods:One hundred and thirty-five lung lesions were biopsied with ENB from January 2017 to August 2019. Biopsies were considered diagnostic if pathology confirmed malignancy or inflammation in the appropriate clinical and imaging setting. We evaluated lesions for several characteristics including size, lobe, and central/peripheral distribution. The diagnostic yield of CTB in patients who failed ENB biopsies was also evaluated. Logistic regression was used to identify factors likely to predict a non-diagnostic ENB biopsy.Result:Overall, ENB biopsies were performed in 135 patients with solitary lung lesions. ENB biopsies were diagnostic in 52% (70/135) of the patients. In 23 patients with solitary lung lesions, CTBs were performed following a non-diagnostic ENB biopsy. The CTBs were diagnostic in 87% of the patients (20/23). ENB biopsies of lesions <21.5 mm were non-diagnostic in 71% of cases (42/59); 14 of these patients with non-diagnostic ENB biopsies had CTBs, and 86% of them were diagnostic (12/14). ENB biopsies of lesions in the lower lobes were non- diagnostic in 59% of cases (35/59); 12 of these patients with non-diagnostic ENB biopsies had CTBs, and 83% were diagnostic (10/12). ENB biopsies of lesions in the outer 2/3 were non-diagnostic in 57% of cases (50/87); 21 of these patients with non-diagnostic ENB biopsies had CTBs, and 86% were diagnostic (18/21).Conclusion:CTBs have a high diagnostic yield even following non-diagnostic ENB biopsies. Lesions <21.5 mm, in the outer 2/3 of the lung, and in the lower lung have the lowest likelihood of a diagnostic yield with ENB biopsies. Although CTBs have a slightly higher pneumothorax rate, these lesions would be more successfully diagnosed with CTB as opposed to ENB biopsy, in the process expediting the diagnosis and saving valuable medical resources.

MRI in Evaluation of Solitary Pulmonary Nodules.

The aim of this study is to assess magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), T2-weighted image (T2WI), and apparent diffusion coefficient (ADC) maps' threshold values before computed tomography (CT)-guided transthorasic biopsy in solitary pulmonary nodules (SPN) by describing tumoral cell density. Patients who had SPN were prospectively evaluated with MRI (T1WI, T2WI) and DWI (b=0, b=500, b=1000).The ADC maps were created for each patient. Before the biopsy, lesion muscle ratios (LMR) at T2WI, ADC value, and lesion spinal cord ratio at each b values were noted. The measurements were correlated with the histopathological results. A total of 53 patients were included in the study: 30.2% (n=16) were female, and 69.8% (n=37) were male. Among them, 17 lesions (32.1%) were benign, and 36 lesions (67.9%) were malignant. The age varied between 40 and 82 years, with a mean of 61.7±9.1 years. The SPN diameters were between 10 and 30 mm, and the median was 24 mm. The LSR0 and LMR values were not statistically significant in detecting malignancy. LSR500 >0.53 value can predict malignancy with 100% sensitivity and 70.6% specificity. LSR1000 >0.53 can predict malignancy with 88.9% sensitivity and 88.2% specificity. Setting the cut-off value at 0.9×10-3, the ADC values had a sensitivity of 72.2% and a specificity of 88.2% for predicting malignancy. For SPN follow-up, a new following-up protocol can be safely established using DWI and ADC mapping. Using these MRI parameters might decrease unnecessary biopsy rates and complications of biopsies.

Diagnosis and management of peripheral lung nodule.

A solitary pulmonary nodule (SPN) is a well-defined radiographic opacity up to 3 cm in diameter that is surrounded by unaltered aerated lung. Frequently, it is an incidental finding on chest radiographs and chest CT scans. Determining the probability of malignancy is the first step in the evaluation of SPN. This can be done by looking at specific risk factors and the rate of radiographic progression. Subsequent management is guided by the type of the nodule. Patients with solid nodules and low pretest probability can be followed radiographically; those with high probability, who are good surgical candidates, can be referred for surgical resection. When the pretest probability is in the intermediate range additional testing such as biopsy should be done. Various modalities are now available to obtain tissue diagnosis. These modalities differ in their yield and complication rate. Patients with SPN should be well informed of each approach's risks and benefits and should be able to make an informed decision regarding the different diagnostic and therapeutic modalities.

Solitary Pulmonary Nodules - What Every Clinician Should Know

<span lang=FR style=mso-bidi-font-size: 10.0pt;font-family: times= new= roman,serif;mso-fareast-font-family:times= roman;= color:black;mso-ansi-language:fr=>1. Abstract Solitary Pulmonary Nodules (SPNs) are one of the most common thoracic radiological finding at computed tomography scans. However, d ealing with SPN is challenging for both surgeons and clinicians. Differentiating a benign from a malignant nodule is usually the major question in the evaluation of SPNs as it defines the proper subsequent management. Here we describe the 3 most used recommendations from important medical societies to guide doctors in managing a SPN. <span style=mso-bidi-font-size:10.0pt; font-family: times= new= roman,serif;mso-fareast-font-family:times= roman;= mso-ansi-language:en-us=>2. <span style=mso-bidi-font-size:10.0pt; font-family: times= new= roman,serif;mso-ansi-language:en-us=>Keywords: Lung Nodule; Malignant Pulmonary Nodule; Solitary Pulmonary Nodule

PET/CT Interpretative Pitfalls in Thoracic Malignancies

Applications of positron emission tomography/computed tomography (PET/CT) in the thorax include the evaluation of solitary pulmonary nodules, staging and restaging of oncologic patients, assessment of therapeutic response, and detection of residual or recurrent disease. Accurate interpretation of PET/CT requires knowledge of the physiological distribution of [18F]-fluoro-2-deoxy-D-glucose, as well as artifacts and quantitative errors due to the use of CT for attenuation correction of the PET scan. Potential pitfalls include malignancies that are PET negative and benign conditions that are PET positive. Awareness of these artifacts and potential pitfalls is important in preventing misinterpretation that can alter patient management.

Radial EBUS versus CT-guided needle biopsy for evaluation of solitary pulmonary nodules

ObjectiveThis study is aimed to compare the diagnostic yield, complications and influencing factors between Radial endobroncheal ultrasonography guided bronchoscopy(R-EBUS) and CT-guided needle biopsy (CT-PNB), for evaluation of solitary pulmonary nodules(SPNs).Matrials and Methods160 cases of consecutive patients with SPNs were enrolled and divided into R-EBUS and CT-PNB groups randomly. The diagnostic yield, complications and influencing factors between the two groups were evaluated.ResultsSensitivity of R-EBUS for malignancy was 73.7% (42/57) and for benign, was 43.5% (10/23), overall diagnostic accuracy was 65% (52/80). In CT-PNB group, overall diagnostic accuracy was 85% (68/80), sensitivity for malignancy was 87.9% (51/58), and for benign was 81.0% (17/21), respectively. Both overall diagnostic yield and incidence of complications in CT-PNB group were higher than those in R-EBUS group (P = 0.006, P = 0.002). In R-EBUS group, the factors affecting diagnostic yield were size (P = 0.027), the distance between SPNs and pleura (P = 0.031) and the location of the probe to lesions (P = 0.009). In CT-PNB group, the distance from the lesions to pleura was correlated with the incidence of pneumothorax (P = 0.001) and pulmonary haemorrhage (P = 0.042). The location of SPNs were adjacent to great vessels was another influencing factor for pulmonary haemorrhage (P = 0.042).ConclusionsBoth R-EBUS and CT-PNB are valuable tools for diagnosis. SPNs located in medial 1/2 of lung field, or were adjacent to great vessels may be fit for R-EBUS. Those SPNs located in lateral 1/2 of lung field, near to pleura or with less vessels around may be more suitable for CT-PNB.

Perspectives on Managing Solitary Pulmonary Nodules: A Survey of Primary Care Physicians

Primary care physicians (PCPs) may be involved in the evaluation of solitary pulmonary nodules (SPNs) detected through lung cancer screening. Little is known about their perspectives on the management or the referral of SPN. Using the American Medical Association's Physician Masterfile, we randomly surveyed 1384 PCPs between January and October 2015 with an 18% response rate. A subset analysis was performed on SPN management and referral practices of PCP. These results and those relating to practice characteristics were compared between family practice and internal medicine physicians. Responders and nonresponders did not differ by demographic characteristics. A total of 137 (55.5%) PCPs reported feeling confident in managing the workup of imaging-detected SPN. However, only 53 PCPs (21.3%) were inclined to manage the evaluation and follow-up of SPN. There was no significant difference between family practice and internal medicine physicians with regard to years in practice, size of practice, or referral to specialists. Family practitioners and internists similarly disagreed or were neutral to self-managing SPN (P = 0.60). Internists were twice as likely to express confidence as family practitioners (odds ratio 1.95, 95% confidence interval 1.09-3.48). Among all PCPs, 75.4% would refer management of these patients to a pulmonologist, 28.9% to a surgeon, and 24.2% to an oncologist. Confidence did not predict lung cancer screening practices. Although more than half of PCPs expressed confidence in the workup of SPN, most preferred referral to specialists. Additional research is needed to understand barriers to PCP management of incidental SPN in the effort to facilitate lung cancer screening.

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.

Clinical utility of F-18 FDG PET-CT in the initial evaluation of lung cancer.

Positron emission tomography-computed tomography (PET-CT) is a resource-demanding imaging modality with increasing popularity in the workup of patients with suspected or proven lung cancer. To review the clinical usefulness of this imaging modality in the diagnosis, staging, and pre-operative evaluation, we conducted a systematic literature search, review, and quality assessment using the rapid evidence assessment toolkit and the Oxford Centre for Evidence-Based Medicine methodology. The literature search resulted in 4,208 records including 918 reviews, of which 139 met the predefined criteria and were read in full to identify relevant original articles on F-18 FDG PET-CT (1) in the evaluation of solitary pulmonary nodules (n = 14), (2) in curative-intent treatment trials (n = 9), and (3) in planning of invasive procedures (n = 18). We found the following important results from the literature review: 1) PET-CT can rule out malignancy in most solitary pulmonary nodules due to high sensitivity (recommendation level A). 2) PET-CT reduces the number of futile treatment trials (recommendation level A). 3) The sensitivity of PET-CT in general is insufficient to rule out mediastinal lymph node metastasis (recommendation level A). ᅟ 1) With few exceptions, solitary pulmonary nodules can safely be considered benign if the PET-CT scan is negative. Exceptions consist of small (<1cm) and non-solid, solitary pulmonary nodules. These abnormalities should be followed up by CT in a structured programme. 2) No curative-intent treatment should be commenced until a PET-CT scan has excluded occult distant metastases. 3) In general, lymph node metastasis in the mediastinum cannot be ruled out on the basis of a negative PET-CT, and confirmative invasive staging should be performed in most patients before mediastinal metastasis is confirmed or ruled out.

The prognostic value of tumor shadow disappearance rate on integrated PET/CT evaluation of solitary pulmonary nodules with low glucose metabolism.

This study aimed to determine the prognostic value of the tumor shadow disappearance rate (TDR) on integrated PET/computed tomography (PET/CT) evaluation of solitary pulmonary nodules (SPNs) with low glucose uptake. From January 2008 to September 2010, 99 patients who underwent fluorine-18 fluorodeoxyglucose PET (F-FDG-PET)/CT scanning for the evaluation of SPNs with a maximum standardized uptake value (SUVmax) below 2.75 (2.5+10%) were retrospectively reviewed. Among the 99 SPNs from these patients, 67 were malignant and 32 were benign, based on surgical pathology. Differences in baseline characteristics between the two groups were examined by means of the independent t-test, the Mann-Whitney U-test, and the χ-test. To test the efficacy of TDR for determining malignancy, the sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and positive and negative likelihood ratios (LR+ and LR-, respectively) with 95% confidence intervals were calculated using the pathological test as the gold standard. Patients with malignant nodules were older than those with benign nodules (64.5 vs. 55.1 years, respectively, P<0.001) and had higher TDRs (0.8 vs. 0.3, respectively, P<0.001). The optimal cutoff point for the TDR was 0.4886 where the sensitivity, specificity, positive predictive value, and negative predictive value were 0.851, 0.844, 0.919, and 0.730, respectively, and the LR+ and LR- were 5.443 and 0177, respectively. A significant negative correlation between TDR and SUVmax was found only in the malignant group. The diagnostic value of TDR complements the PET/CT evaluation of SPNs with a low F-FDG uptake.

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.

Respiratory-gated imaging in metabolic evaluation of small solitary pulmonary nodules: 18F-FDG PET/CT and correlation with histology.

The aim of the study was to evaluate the effect of 2-((18)F)-fluoro-2-deoxy-D-glucose ((18)F-FDG)-PET/computed tomography (CT) respiratory-gated imaging [four-dimensional (4D)] in the metabolic evaluation of small solitary pulmonary nodules and analyze the cutoff maximum standardized uptake value (SUV(max)) of 2.5 in classifying and distinguishing benign/malignant pulmonary pathologies in 4D studies. Thirty-two patients with pulmonary lesions measuring 2 cm or less were included during their scheduled (18)F-FDG PET/CT examinations. The whole-body PET/CT acquisition (3D) was followed by a chest-centered PET/CT (4D) study synchronized with the respiratory cycle. The SUV(max) percentage difference (%Diff SUV(max)) was calculated. The nodule size, localization, and relationships with histological/cytological findings were studied. Fifteen nodules were 10 mm or smaller and 17 were larger than 10 mm [mean size = 12 mm (7-20)]. The mean 3D-SUV(max) was 2.5 (0.7-6.1) and the mean 4D-SUV(max) 3.2 (0.9-7.2) (P < 0.001). The mean %Diff SUV(max) was 38% for all patients (7-90), 45% in subcentimetric (7-90%) and 31% (7-75%) in supracentimetric lesions (P = NS). Histology was obtained in 23/32 (72%) cases and the pathologic benign/malignant ratio was 4/19. Malignancies were diagnosed as lung adenocarcinoma, solitary metastases, large cell lung carcinoma, and sarcoma in 13 (41%), 3 (9%), 2 (6%), and 1 (3%) case, respectively. Malignant lesions showed mean 4D-SUV(max) of 3.8 (1.2-7.2). The cutoff SUV(max) of 2.5 did not classify and distinguish between benign/malignant pulmonary pathologies, neither in 3D nor in 4D studies. Respiratory gating improves the detectability and metabolic evaluation of solitary pulmonary nodules, mostly those that are subcentimetric. However, as expected, the cutoff SUV(max) of 2.5 does not distinguish between benign/malignant lesions in either 4D or 3D studies.

PET–CT Evaluation of Solitary Pulmonary Nodules: Correlation with Maximum Standardized Uptake Value and Pathology

18-fluorine fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) has an established role for the characterization of solitary pulmonary nodules (SPN). Visual assessment of nodule morphology, together with maximum standardized uptake value (SUVmax), is used to estimate likelihood of malignancy. We correlated SUVmax value with pathology of SPN and assessed diagnostic accuracy in differentiating malignant from benign nodule, using 2.5 as threshold SUVmax. Retrospective review of PET-CT scans for SPN characterization between April 2008 and June 2011 was performed. Only cases with pathological verification were included. A total of 641 PET-CTs were performed for SPN characterization and staging; 186 patients (77 males, 109 females) with pathological confirmation were included, and 158 (85%) nodules were malignant: adenocarcinomas (n=66), squamous cell carcinomas (n=40), and metastases (n=20) were the commonest. 28 lesions (15%) were benign, including granuloma/chronic inflammation (n=8), infection (n=7), and hamartomas (n=5). Using cutoff SUVmax of 2.5, the accuracy of PET-CT in diagnosing malignant SPN is 81.2%, with sensitivity 86.7%, specificity 50%, PPV 90.7%, and NPV 40%. The likelihood of malignancy increases with SUVmax. Nevertheless, even with SUVmax <2.5, there is a 62% chance that a nodule is malignant. Although PET-CT is useful in diagnostic workup of SPN, it cannot replace "gold standard" tissue diagnosis.