Potential impact of texture analysis in contrast enhanced CT in non-small cell lung cancer as a marker of survival: A retrospective feasibility study.

The objective of this feasibility study was to assess computed tomography (CT) texture analysis (CTTA) of pulmonary lesions as a predictor of overall survival in patients with suspected lung cancer on contrast-enhanced computed tomography (CECT). In a retrospective pilot study, 94 patients (52 men and 42 women; mean age, 67.2 ±â€…10.8 yrs) from 1 center with non-small cell lung cancer (NSCLC) underwent CTTA on the primary lesion by 2 individual readers. Both simple and multivariate Cox regression analyses correlating textural parameters with overall survival were performed. Statistically significant parameters were selected, and optimal cutoff values were determined. Kaplan-Meier plots based on these results were produced. Simple Cox regression analysis showed that normalized uniformity had a hazard ratio (HR) of 16.059 (3.861-66.788, P < .001), and skewness had an HR of 1.914 (1.330-2.754, P < .001). The optimal cutoff values for both parameters were 0.8602 and 0.1554, respectively. Normalized uniformity, clinical stage, and skewness were found to be prognostic factors for overall survival in multivariate analysis. Tumor heterogeneity, assessed by normalized uniformity and skewness on CECT may be a prognostic factor for overall survival.

Can visual assessment of blood flow patterns by dynamic contrast-enhanced computed tomography distinguish between malignant and benign lung tumors?

BACKGROUND: Dynamic contrast-enhanced computed tomography (DCE-CT) is a tool, which, in theory, can quantify the blood flow and blood volume of tissues. In structured qualitative analysis, parametric color maps yield a visual impression of the blood flow and blood volume within the tissue being studied, allowing for quick identification of the areas with the highest or lowest blood flow and blood volume. PURPOSE: To examine whether DCE-CT could be used to distinguish between malignant and benign lung tumors in patients with suspected lung cancer. MATERIAL AND METHODS: Fifty-nine patients with suspected lung cancer and a lung tumor on their chest radiograph were included for DCE-CT. The tumors were categorized using structured qualitative analysis of tumor blood flow patterns. Histopathology was used as reference standard. RESULTS: Using structured qualitative analysis of tumor blood flow patterns, it was possible to distinguish between malignant and benign lung tumors (Fisher-Freeman-Halton exact test, P = 0.022). The inter-reader agreement of this method of analysis was slight to moderate (kappa = 0.30; 95% confidence interval [CI] = 0.13-0.46). CONCLUSION: DCE-CT in suspected lung cancer using structured qualitative analysis of tumor blood flow patterns is accurate as well as somewhat reproducible. However, there are significant limitations to DCE-CT.

CT texture analysis can help differentiate between malignant and benign lymph nodes in the mediastinum in patients suspected for lung cancer.

BACKGROUND: In patients with non-small-cell lung carcinoma NSCLC the lymph node staging in the mediastinum is important due to impact on management and prognosis. Computed tomography texture analysis (CTTA) is a postprocessing technique that can evaluate the heterogeneity of marked regions in images. PURPOSE: To evaluate if CTTA can differentiate between malignant and benign lymph nodes in a cohort of patients with suspected lung cancer. MATERIAL AND METHODS: With tissue sampling as reference standard, 46 lymph nodes from 29 patients were analyzed using CTTA. For each lymph node, CTTA was performed using a research software "TexRAD" by drawing a region of interest (ROI) on all available axial contrast-enhanced computed tomography (CT) slices covering the entire volume of the lymph node. Lymph node CTTA comprised image filtration-histogram analysis undertakes two stages: the first step comprised an application of a Laplacian of Gaussian filter to highlight fine to coarse textures within the ROI, followed by a quantification of textures via histogram analysis using mean gray-level intensity from the entire volume of the lymph nodes. RESULTS: CTTA demonstrated a statistically significant difference between the malignant and the benign lymph nodes (P = 0.001), and by binary logistic regression we obtained a sensitivity of 53% and specificity of 97% in the test population. The area under the receiver operating curve was 83.4% and reproducibility was excellent. CONCLUSION: CTTA may be helpful in differentiating between malignant and benign lymph nodes in the mediastinum in patients suspected for lung cancer, with a low intra-observer variance.

Mediastinal staging in Non-Small-Cell Lung Carcinoma: computed tomography versus F-18-fluorodeoxyglucose positron-emission tomography and computed tomography.

BACKGROUND: After the diagnosis Non-Small-Cell Lung Carcinoma (NSCLC) has been established, consideration must turn toward the stage of disease, because this will impact directly on management and prognosis. Staging is used to predict survival and to guide the patient toward the most appropriate treatment regimen or clinical trial. Distinguishing malignant involvement of the mediastinal lymph nodes (N2 or N3) from the hilar lymph nodes, or no lymph nodes (N0 or N1) is critical, because malignant involvement of N2 or N3 lymph nodes usually indicates non-surgically resectable disease. The purpose of this study was to examine and compare CT versus integrated F18-FDG PET/low dose CT (FDG PET/CT) for mediastinal staging in NSCLC, and the desire was to safely distinguish between malignant and benign lesions without the need for invasive procedures. All results were controlled for reproducibility. METHODS: 114 participants with NSCLC were included in a prospective cohort study. Blinded CT and FDG PET/CT images were reviewed. The participants' mediastinums were staged based on lymph node sizes (CT), or on FDG uptake (FDG PET/CT). Reference standard was tissue sampling. RESULTS: We found that there was no measureable difference between CT and FDG PET/CT mediastinal staging results; overall two-thirds of the participants in the study were correctly staged, and almost one-third of the participants were falsely staged. CONCLUSION: Neither CT nor FDG PET/CT could obviate the need for further invasive staging prior to thoracotomy in patients with NSCLC; for that purpose, the results of both modalities were too meagre. Therefore, these patients still depend on invasive staging methods. In our study, invasive staging was accomplished by mediastinoscopy. However, today this is increasingly replaced by EBUS or EUS.

LUCIS: lung cancer imaging studies.

Pulmonary nodules are of high clinical importance, as they may prove to be an early manifestation of lung cancer. Pulmonary nodules are small, focal opacities that may be solitary or multiple. A solitary pulmonary nodule (SPN) is a single, small (= 30 mm in diameter) radiographic opacity. Larger opacities are called masses and are often malignant. As imaging techniques improve and more nodules are detected, the optimal management of SPNs remains unclear. Current strategies include tissue sampling or CT follow-up. The aim of this PhD was to examine current non-invasive methods used to characterise pulmonary nodules and masses in patients with suspected lung cancer and to stage NSCLC. In doing so, this PhD helps to validate the existing methods used to diagnose and stage lung cancer correctly and, hopefully, aids in the development of new methods. In the first study, 213 participants with pulmonary nodules on CT were examined with an additional HRCT. In this study, it was concluded that HRCT of a solitary pulmonary nodule, assessed using attenuation and morphological criteria is a fast, widely available and effective method for diagnosing lung cancer correctly, and especially for ruling out cancer. In the second study, 168 patients with pulmonary lesions on CT were examined with an additional F-18-FDG PET/CT. It was concluded that when used early in the work-up of the lesions, CT raised the prevalence of lung cancer in the population to the point at which further diagnostic imaging examination could be considered redundant. Standard contrast-enhanced CT seems better suited to identify patients with lung cancer than to rule out cancer. Finally, the overall diagnostic accuracy as well as the classification probabilities and predictive values of the two modalities were not significantly different. The reproducibility of the above results was substantial. In the third study, 59 patients with pulmonary nodules or masses on chest radiography were examined with an additional DCE-CT. A qualitative as well as a quantitative assessment method was examined. It was concluded that although the results of the qualitative approach were acceptable in their own right, they did not, however, add anything new when compared to standard CT. The quantitative approach gave rise to several conclusions concerning DCE-CT analysis as well as the use of DCE-CT in the diagnosis of lung cancer: First, that DCE-CT is best analysed using logarithmic scale data transformation; second, that irrespective of the ROI method applied, it was not possible to discriminate malignant and benign; and, third, that the lack of reproducibility should be addressed. These results show us that DCE-CT is currently not a clinically feasible method for analysing pulmonary lesions. This does not necessarily mean that DCE-CT should be abandoned, but it does signify the need for further development of the current DCE-CT methods. Finally, in the fourth study, 114 patients with NSCLC were examined with both a CT and with an additional F-18-FDG PET/CT. It was concluded that there was no significant difference in the overall diagnostic accuracy of the two modalities when imaging the mediastinum for staging purposes. In conclusion, although standard contrast-enhanced CT has brought us far in the characterisation of pulmonary nodules and masses, the last decade has seen a constant move away from strictly anatomical approaches to imaging, towards more functional or analytical approaches. The desire is, of course, to be able to safely distinguish between malignant and benign nodules without the need for invasive procedures.

Characterization of pulmonary lesions in patients with suspected lung cancer: computed tomography versus [¹8F] fluorodeoxyglucose-positron emission tomography/computed tomography.

Pulmonary nodules are of high clinical importance, given they may prove to be an early manifestation of lung cancer. Pulmonary nodules are small, focal, radiographic opacities that may be solitary or multiple. A solitary pulmonary nodule is a single, small (<-30 mm in diameter) opacity. Larger opacities are called masses and are often malignant. As imaging techniques improve and more nodules are detected, the optimal management of pulmonary nodules remains unclear. However, the question of malignancy of any given nodule remains the same. A standard contrast-enhanced computed tomography (CT) scan is often the first examination, followed by a number of other examinations. The purpose of this study was to examine the clinical feasibility of CT versus integrated [18F]fluorodeoxyglucose-positron emission tomography (PET)/low-dose CT scan in patients with suspected lung cancer and pulmonary lesions on CT. All results were controlled for reproducibility. We found that when used early in the work-up of the lesions, CT raised the prevalence of lung cancer in the population to the point where further diagnostic imaging examination could be considered futile. We also found that the overall diagnostic accuracy, as well as the classification probabilities and predictive values of the two modalities were not significantly different; the reproducibility of these results was substantial.

High resolution spiral CT for determining the malignant potential of solitary pulmonary nodules: refining and testing the test.

BACKGROUND: A solitary pulmonary nodule (SPN) may represent early stage lung cancer. Lung cancer is a devastating disease with an overall 5-year mortality rate of approximately 84% but with early detection and surgery as low as 47%. Currently a contrast-enhanced multiple-row detector CT (MDCT) scan is the first examination when evaluating patients with suspected lung cancer. PURPOSE: To apply an additional high resolution CT (HRCT) to SPNs to test whether certain morphological characteristics are associated with malignancy, to assess the diagnostic accuracy of HRCT in the characterization of SPNs, and to address the reproducibility of all measures. MATERIAL AND METHOD: Two hundred and thirteen participants with SPNs were included in a follow-up study. Blinded HRCT images were assessed with regard to margin risk categories (MRCs), calcification patterns and certain other characteristics and overall malignancy potential ratings (MPRs) were given. Morphological characteristics were tested against reference standard and ROC methodology was applied to assess diagnostic accuracy. Reproducibility was measured with Kappa statistics and 95% confidence intervals were computed for all results. Histopathology (90%) and CT follow-up (10%) were used as reference standard. RESULTS: MRCs (P < 0.001), calcification patterns (P = 0.003), and pleural retraction (P < 0.001) were all statistically significantly associated to malignancy. Reproducibility was moderate to substantial. Sensitivity, specificity, and overall diagnostic accuracy of HRCT were 98%, 23% and 87%, respectively. Reproducibility was substantial. CONCLUSION: Statistically significant associations between SPN MRCs, calcification patterns, pleural retraction and malignancy were found. HRCT yielded a very high sensitivity and a somewhat lower specificity for malignancy. Reproducibility was high.