Evaluation Of Small Pulmonary Nodules Research Articles

Radiographic assessment of small lung nodules: what can we do and what information does it give us?

: The evaluation of small pulmonary nodules is a common and challenging clinical scenario often requiring a multi-disciplinary approach to optimize patient care. Radiographic assessment of pulmonary nodules is an important part of the determination of whether a nodule is malignant or benign which then translates into an intervention or a management strategy. A multimodality radiological approach or longitudinal follow up may be needed based on a combination of the clinical and imaging features at initial presentation. In this article, we illustrate the role of anatomical and functional radiological techniques [chest radiography, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT)] in the assessment and characterization of small pulmonary nodules, with an emphasis on chest CT, the workhorse of pulmonary imaging. This discussion is framed in the context of how imaging fits into current international guidelines on pulmonary nodule assessment, with an emphasis on both the Fleischner society and British Thoracic Society (BTS) guidelines, including the application of nodule risk prediction scores. Emerging applications including radiomics, machine learning and artificial intelligence (AI) in assessment and characterization of pulmonary nodules and role of these advanced techniques in the management of pulmonary nodules in the future are also illustrated.

Comparison of Bayesian penalized likelihood reconstruction versus OS-EM for characterization of small pulmonary nodules in oncologic PET/CT

To determine whether the recently introduced Bayesian penalized likelihood PET reconstruction (Q.Clear) increases the visual conspicuity and SUVmax of small pulmonary nodules near the PET resolution limit, relative to ordered subset expectation maximization (OS-EM). In this institutional review board-approved and HIPAA-compliant study, 29 FDG PET/CT scans performed on a five-ring GE Discovery IQ were retrospectively selected for pulmonary nodules described in the radiologist's report as "too small to characterize", or small lung nodules in patients at high risk for lung cancer. Thirty-two pulmonary nodules were assessed, with mean CT diameter of 8mm (range 2-18). PET images were reconstructed with OS-EM and Q.Clear with noise penalty strength β values of 150, 250, and 350. Lesion visual conspicuity was scored by three readers on a 3-point scale, and lesion SUVmax and background liver and blood pool SUVmean and SUVstdev were recorded. Comparison was made by linear mixed model with modified Bonferroni post hoc testing; significance cutoff was p<0.05. Q.Clear improved lesion visual conspicuity compared to OS-EM at β=150 (p<0.01), but not 250 or 350. Lesion SUVmax was increased compared to OS-EM at β=150 and 250 (p<0.01), but not 350. In a cohort of small pulmonary nodules with size near an 8mm PET full-width half maximum, Q.Clear significantly increased lesion visual conspicuity and SUVmax compared to our standard non- time-of-flight OS-EM reconstruction, but only with low noise penalization. Q.Clear with β=150 may be advantageous when evaluation of small pulmonary nodules is of primary concern.

Detection of Small Pulmonary Nodules with Ultrashort Echo Time Sequences in Oncology Patients by Using a PET/MR System.

To investigate the utility of a free-breathing ultrashort echo time (UTE) sequence for the evaluation of small pulmonary nodules in oncology patients by using a hybrid positron emission tomography (PET)/magnetic resonance (MR) imaging system and to compare the nodule detection rate between UTE and a conventional three-dimensional gradient-recalled-echo (GRE) technique. In this HIPAA-compliant, institutional review board-approved prospective study, 82 pulmonary nodules were identified in eight patients with extrathoracic malignancies. Patients underwent free-breathing UTE and dual-echo three-dimensional GRE imaging of the lungs in a hybrid PET/MR imaging unit immediately after clinical PET/computed tomography (CT). CT was considered the reference standard for nodule detection. Two reviewers identified nodules and obtained measurements on MR images. The McNemar test was used to evaluate differences in nodule detection rate between MR techniques, and interrater agreement was assessed by using Bland-Altman plots. Mean nodule diameter ± standard deviation was 6.2 mm ± 2.7 (range, 3-17 mm). The detection rate was higher for UTE imaging than for dual-echo GRE imaging for nodules of at least 4 mm (82% vs 34%, respectively; P < .001), with the largest difference in detection noted in the 4-8-mm nodule group (79% vs 21%, P < .001). UTE imaging displayed a higher detection rate than dual-echo GRE imaging for nodules without fluorodeoxyglucose avidity (68% vs 22%, respectively; P < .001). Interrater reliability of nodule detection with MR imaging was high (κ = 0.90 for UTE imaging and κ = 0.92 for dual-echo GRE imaging). A free-breathing UTE sequence has high sensitivity for the detection of small pulmonary nodules (4-8 mm) and outperformed a three-dimensional dual-echo GRE technique for the detection of small, non-fluorodeoxyglucose-avid nodules.

Comparing 18F-Fluorodeoxyglucose Positron Emission Tomography and Video-assisted Thoracoscopic Surgery in the Evaluation of Small Pulmonary Nodules in Patients with a History of Malignancy

BackgroundThe aims of the study were to determine the accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) in detecting pulmonary metastasis through video-assisted thoracoscopic surgery (VATS), a technique that allows the excisional biopsy of small pulmonary nodules in patients with known malignancies.Materials and MethodsBetween October 2007 and April 2010, 28 patients with known malignancies and small pulmonary nodules underwent VATS excisional biopsies. All patients were in follow-up for a previously treated malignancy. The malignancies included the following: colorectum (9), breast (6), head and neck (5), stomach (3), lymph (1), ovary (1), uterus (1), bladder (1), and liver (1).ResultsThere were 16 men and 12 women whose mean age was 56.7 years old (range, 38 to 77 years). The sizes of the mean nodules removed were 11.3 mm (range, 7 to 21 mm). Diagnoses included metastatic (11), bronchioloalveolar carcinoma (1), primary adenocarcinoma (1), pulmonary tuberculosis (6), fibrosis (5), organizing pneumonia (3), lymphoid hyperplasia (1). Among these lesions, 46.4% were malignant.ConclusionTrue positive FDG-PET was 39.2%. FDG-PET is not a sensitive test in the evaluation of patients with a history of an extrathoracic malignancy and newly diagnosed small pulmonary nodules. VATS excision allows the early diagnosis of small pulmonary nodules, with low morbidity, in patients with known malignancies.

C-Arm Cone-Beam CT-Guided Percutaneous Transthoracic Lung Biopsy: Usefulness in Evaluation of Small Pulmonary Nodules

The purpose of this study was to evaluate the usefulness of C-arm conebeam CT-guided percutaneous transthoracic lung biopsy of small (≤ 2 cm) lung nodules. Twenty-seven patients who underwent C-arm cone-beam CT-guided percutaneous transthoracic lung biopsy of small (≤ 2 cm) lung nodules were enrolled in the study. The mean nodule size was 13 ± 4 mm in diameter. These lesions were divided into two groups according to size: 10 lesions 1 cm or smaller and 17 lesions larger than 1 cm. The diagnostic accuracy, sensitivity, and specificity in the two groups were compared by use of Fisher's exact test. Radiation dose in a female humanoid phantom was measured with radiophotoluminescent glass dosimeters. The average patient dose was calculated. Eighteen malignant (67%) and eight benign (30%) nodules and one (3%) indeterminate nodule were found. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 94%, 89%, 94%, 89%, and 92%. The sensitivity, specificity, and accuracy were 100%, 75%, and 90% for the lesions 1 cm or smaller and 91%, 100%, and 94% for the lesions larger than 1 cm. The accuracy, sensitivity, and specificity did not differ significantly between the groups (all p > 0.05, Fisher's exact test). The average radiation dose among 27 patients was 4.6 mSv (range, 2.19-9.37). C-arm cone-beam CT-guided percutaneous transthoracic lung biopsy is a useful diagnostic technique in the evaluation of small lung nodules.

Nodulo polmonare: caratteristiche clinico-radiologiche che possono influenzare la diagnosi di malignità

The role of computed tomography (CT) in the diagnosis of the solitary pulmonary nodule (SPN) is constantly expanding. CT helps to detect a growing number of increasingly small lesions, but, as with chest radiography, the primary goal in the evaluation of small pulmonary nodules is to exclude malignancy. Despite the availability of numerous, variously invasive, diagnostic tests, diagnostic accuracy tends to decline as the size of the nodule decreases. The role of the radiologist is therefore to help the clinician determine the most appropriate management strategy by using all available modalities [CT, magnetic resonance (MR) imaging, positron emission tomography (PET)] and evaluating the patient's clinical history and the imaging features leading to a diagnosis of benignity or malignancy. Imaging features include nodule size, margins, calcifications and fatty component, internal features (cavitations, pseudocavitations, air bronchogram, halo sign), as well as advanced techniques for characterisation (growth rate, contrast enhancement) and management (computer-aided diagnosis, Bayesian analysis, neural networks). The aim of this paper is to summarise the approach to pulmonary nodules from the point of view of the radiologist, oncologist and thoracic surgeon.

Relation between nodule size and 18F-FDG-PET SUV for malignant and benign pulmonary nodules.

The most common semiquantitative method of evaluation of pulmonary lesions using 18F-FDG PET is FDG standardized uptake value (SUV). An SUV cutoff of 2.5 or greater has been used to differentiate between benign and malignant nodules. The goal of our study was to investigate the correlation between the size of pulmonary nodules and the SUV for benign as well as for malignant nodules.Retrospectively, 173 patients were selected from 420 referrals for evaluation of pulmonary lesions. All patients selected had a positive CT and PET scans and histopathology biopsy. A linear regression equation was fitted to a scatter plot of size and SUVmax for malignant and benign nodules together. A dot diagram was created to calculate the sensitivity, specificity, and accuracy using an SUVmax cutoff of 2.5.The linear regression equations and (R2)s as well as the trendlines for malignant and benign nodules demonstrated that the slope of the regression line is greater for malignant than for benign nodules. Twenty-eight nodules of group one (≤ 1.0 cm) are plotted in a dot diagram using an SUVmax cutoff of 2.5. The sensitivity, specificity, and accuracy were calculated to be 85%, 36% and 54% respectively. Similarly, sensitivity, specificity, and accuracy were calculated for an SUVmax cutoff of 2.5 and found to be 91%, 47%, and 79% respectively for group 2 (1.1–2.0 cm); 94%, 23%, and 76%, respectively for group 3 (2.1–3.0 cm); and 100%, 17%, and 82%,, respectively for group 4 (> 3.0 cm). The previous results of the dot diagram indicating that the sensitivity and the accuracy of the test using an SUVmax cutoff of 2.5 are increased with an increase in the diameter of pulmonary nodules.The slope of the regression line is greater for malignant than for benign nodules. Although, the SUVmax cutoff of 2.5 is a useful tool in the evaluation of large pulmonary nodules (> 1.0 cm), it has no or minimal value in the evaluation of small pulmonary nodules (≤ 1.0 cm).

O-35 Utility of FDG-PET in the diagnostic evaluation of small pulmonary nodules

O-35 Utility of FDG-PET in the diagnostic evaluation of small pulmonary nodules