OBJECTIVE. The purpose of this article is to review the safety and efficacy of thermal ablation of lung malignancies after pneumonectomy.

MATERIALS AND METHODS. We reviewed patients who underwent thermal ablation for malignant lung tumors after pneumonectomy between 1999 and 2009. Patient demographics, complications, procedural success, and oncologic outcomes were recorded. Technique effectiveness was evaluated at imaging 4–6 weeks after ablation. The Kaplan-Meier method was used to evaluate overall survival. A cumulative incidence and competing risk method was used to account for progression-free tumors at the time of patient death.

RESULTS. Of 619 lung ablations, 17 were performed to treat 13 tumors (nine primary and four metastatic) in 12 patients with a single lung. The median tumor size was 2 cm (range, 1.2–4 cm). Technical success was documented in all 17 cases. Technical effectiveness was documented in 10 of 12 patients. Local tumor progression occurred in five lesions within a median of 12 months (range, 10–22 months) after ablation and was treated with repeat ablation in four lesions. Complications included six (35%) of 17 pneumothoraces requiring thoracostomy. Deaths occurred within 2–12 days after three (19%) of 16 ablation sessions. The median time to primary local tumor progression was 18 months (95% CI, 12 months through not reached), and the median time to assisted (after repeat ablation) local tumor progression was 33 months (95% CI, not reached). Median overall survival was 21 months (95% CI, 18–53 months). After excluding the two early deaths complicating the initial ablation procedure, median overall survival was 37 months.

CONCLUSION. Thermal ablation can offer local tumor control after pneumonectomy, despite a relatively high postprocedure clinical risk.

OBJECTIVE. The primary objective of our study was to compare the effect of a chest radiography computer-aided detection (CAD) system on the follow-up recommendations of chest radiologists, general radiologists, and pulmonologists.

MATERIALS AND METHODS. A chest radiography CAD system (RapidScreen 1.1) that has been approved by the U.S. Food and Drug Administration (FDA) and a second-generation version of the system (OnGuard 3.0) not yet approved by the FDA were applied to single frontal radiographs of 200 patients at high risk for lung cancer. One hundred patients had actionable nodules (mean size, 16.9 mm) and 100 patients did not. Six chest radiologists, six general radiologists, and six pulmonologists independently interpreted each image first without CAD and then with CAD during blinded reading sessions. The frequency with which readers correctly referred patients for follow-up tests was measured. Differential effects based on nodule size, shape, location, density, and subtlety were tested with multiplevariable logistic regression.

RESULTS. For patients without actionable lesions, pulmonologists showed an increase in their recommendations for follow-up from 0.46 unaided to 0.52 with CAD (p = 0.001), whereas chest and general radiologists had much lower average rates and were not affected by CAD's false marks (0.26 without CAD vs 0.25 with RapidScreen 1.1 and 0.26 with OnGuard 3.0, p ≥ 0.734). CAD improved all readers' detection of moderately subtle lesions (p = 0.013) but did not significantly increase follow-up rates overall for patients with actionable nodules (0.63 unaided vs 0.63 with RapidScreen 1.1, p = 0.795; and 0.63 unaided vs 0.64 with OnGuard 3.0, p = 0.187).

CONCLUSION. The effect of CAD on readers' clinical decisions varies depending on the training of the reader. CAD did not improve the performance of chest or general radiologists. Nonradiologists are particularly vulnerable to CAD's false-positive marks.

OBJECTIVE. The purpose of this article is to evaluate radiologists' ability to detect subtle nodules by use of standard chest radiographs alone compared with bone suppression imaging used together with standard radiographs.

MATERIALS AND METHODS. The cases used in this observer study comprised radiographs of 72 patients with a subtle nodule and 79 patients without nodules taken from the Japanese Society of Radiological Technology nodule database. A new image-processing system was applied to the 151 radiographs to create corresponding bone suppression images. Two image reading sets were used with an independent test method. The first reading included half of the patients (a randomly selected subset A) showing only the standard image and the remaining half (subset B) showing the standard image plus bone suppression images. The second reading entailed the same subsets; however, subset A was accompanied by bone suppression images, whereas subset B was shown with only the standard image. The two image sets were read by three experienced radiologists, with an interval of more than 2 weeks between the sessions. Receiver operating characteristic (ROC) curves, with and without localization, were obtained to evaluate the observers' performance.

RESULTS. The mean value of the area under the ROC curve for the three observers was significantly improved, from 0.840 with standard radiographs alone to 0.863 with additional bone suppression images (p = 0.01). The area under the localization ROC curve was also improved with bone suppression imaging.

CONCLUSION. The use of bone suppression images improved radiologists' performance in the detection of subtle nodules on chest radiographs.