Faculty Bibliography

OBJECTIVE: The purpose of this study was to assess the impact of an automated program on improvement in lung nodule matching efficiency. MATERIALS AND METHODS: Four thoracic radiologists independently reviewed two serial chest CT examinations from each of 57 patients. Each radiologist performed timed manual lung nodule matching. After 6 weeks, all radiologists independently repeated the timed matching portion using an automated nodule matching program. The time required for manual and automated matching was compared. The impact of nodule size and number on matching efficiency was determined. RESULTS: An average of 325 (range, 244-413) noncalcified solid pulmonary nodules was identified. Nodule matching was significantly faster with the automated program irrespective of the interpreting radiologist (p < 0.0001 for each). The maximal time saved with automated matching was 11.4 minutes (mean, 2.3 +/- 2.0 minutes). Matching was faster in 56 of 57 cases (98.2%) for three readers and in 46 of 57 cases (80.7%) for one reader. There were no differences among readers with respect to the mean time saved per matched nodule (p > 0.5). The automated program achieved 90%, 90%, 79%, and 92% accuracy for the four readers. The improvement in efficiency for a given patient using the automated technique was proportional to the number of matched nodules (p < 0.0001) and inversely proportional to nodule size (p < 0.05). CONCLUSION: Use of the automated lung nodule matching program significantly improves diagnostic efficiency. The time saved is proportionate to the number of nodules identified and inversely proportional to nodule size. Adoption of such a program should expedite CT examination interpretation and improve report turnaround time.

OBJECTIVE: The objective of our study was to identify the significance of lung nodules reported on abdominal CT. MATERIALS AND METHODS: Abdominal CT reports from a 1-year period were reviewed for the terms "nodule," "nodular," or "mass" in reference to the lung bases. Patients with prior chest or abdominal CT examinations were excluded; the study population included patients with an initial abdominal CT study and at least one follow-up chest or abdominal CT examination. Two thoracic radiologists characterized nodules in consensus. Radiology and clinical records were reviewed for nodule growth and clinical diagnoses. RESULTS: The term "nodule," "nodular," or "mass" in reference to the lung bases was reported in 364 of 12,287 abdominal CT studies (3%). Of 125 patients with no prior CT examination, 42 had undergone follow-up chest CT, abdominal CT, or both. Common imaging indications included abdominal pain (13/42, 31%) and preexisting malignancy (n = 7, 16.7%). Regardless of the indication for imaging, 16 (38.1%) had malignancy that was known (n = 13) or newly diagnosed (n = 3) on the initial abdominal CT. Three of 42 patients (7.1%) had malignant nodules representing metastatic disease: Nodule growth was seen in one patient with preexisting colon cancer, one patient with newly diagnosed metastatic pancreatic cancer, and a third with known bladder cancer. The latter patient had suspected lung metastases that were confirmed on chest CT 1 day later. Three of the 16 patients (18.8%) with preexisting or newly diagnosed cancer had malignant nodules. No malignant nodules were identified without such history. Six patients (14.3%) had an infection. CONCLUSION: Lung nodules incidentally detected on abdominal CT were rarely malignant and were seen only in the setting of an underlying abdominal malignancy. Knowledge of such history is of critical importance to both the clinician and the radiologist. Dedicated chest CT is most useful when assessing pulmonary nodules in patients with localized malignancy.

PURPOSE: To determine the precision of a three-dimensional (3D) method for measuring the growth rate of solid and subsolid nodules and its ability to detect abnormal growth rates. MATERIALS AND METHODS: This study was approved by the Institutional Research Board and was HIPAA compliant. Informed consent was waived. The growth rates of 123 lung nodules in 59 patients who had undergone lung cancer screening computed tomography (CT) were measured by using a 3D semiautomated computer-assisted volume method. Clinical stability was established with long-term CT follow-up (mean, 6.4 years+/-1.9 [standard deviation]; range, 2.0-8.5 years). A mean of 4.1 CT examinations per patient+/-1.2 (range, two to seven CT examinations per patient) was analyzed during 2.4 years+/-0.5 after baseline CT. Nodule morphology, attenuation, and location were characterized. The analysis of standard deviation of growth rate in relation to time between scans yielded a normative model for detecting abnormal growth. RESULTS: Growth rate precision increased with greater time between scans. Overall estimate for standard deviation of growth rate, on the basis of 939 growth rate determinations in clinically stable nodules, was 36.5% per year. Peripheral location (P=.01; 37.1% per year vs 25.6% per year) and adjacency to pleural surface (P=.05; 38.9% per year vs 34.0% per year) significantly increased standard deviation of growth rate. All eight malignant nodules had an abnormally high growth rate detected. By using 3D volumetry, growth rate-based diagnosis of malignancy was made at a mean of 183 days+/-158, compared with radiologic or clinical diagnosis at 344 days+/-284. CONCLUSION: A normative model derived from the variability of growth rates of nodules that were stable for an average of 6.4 years may enable identification of lung cancer.

BACKGROUND AND PURPOSE: To determine the optimal method of targeting breast and regional nodes in selected breast cancer patients after axillary dissection, we compared the results of IMRT versus no IMRT, and CT-informed versus clinically-placed fields, in supine and prone positions. MATERIALS AND METHODS: Twelve consecutive breast cancer patients simulated both prone and supine provided the images for this study. Four techniques were used to target breast, level III axilla, and supraclavicular fossa in either position: a traditional three-field three-dimensional conformal radiotherapy (3DCRT) plan, a four-field 3DCRT plan using a posterior axillary boost field, and two techniques using a CT-informed target volume consisting of an optimized 3DCRT plan (CT-planned 3D) and an intensity-modulated radiotherapy (IMRT) plan. The prescribed dose was 50Gy in 25 fractions. RESULTS: CT-planned 3D and IMRT techniques improved nodal PTV coverage. Supine, mean nodal PTV V50 was 50% (3-field), 59% (4-field), 92% (CT-planned 3D), and 94% (IMRT). Prone, V50 was 29% (3-field), 42% (4-field), 97% (CT-planned 3D), and 95% (IMRT). Prone positioning, compared to supine, and IMRT technique, compared to 3D, lowered ipsilateral lung V20. CONCLUSIONS: Traditional 3DCRT plans provide inadequate nodal coverage. Prone IMRT technique resulted in optimal target coverage and reduced ipsilateral lung V20

Advances in multidetector technology have made dual-energy computed tomography (CT) imaging possible. Dual-energy CT imaging enables tissue characterization in addition to morphologic evaluation of imaged regions. This article reviews current and potential CT technology, technical and workflow considerations when performing dual-energy CT, and clinical applications in the thorax, with an emphasis on the knowledge gained so far

OBJECTIVE: : To describe pathologic findings in symptomatic World Trade Center-exposed local workers, residents, and cleanup workers enrolled in a treatment program. METHODS: : Twelve patients underwent surgical lung biopsy for suspected interstitial lung disease (group 1, n = 6) or abnormal pulmonary function tests (group 2, n = 6). High-resolution computed axial tomography and pathologic findings were coded. Scanning electron microscopy with energy-dispersive x-ray spectroscopy was performed. RESULTS: : High-resolution computed axial tomography showed reticular findings (group 1) or normal or airway-related findings (group 2). Pulmonary function tests were predominantly restrictive. Interstitial fibrosis, emphysematous change, and small airway abnormalities were seen. All cases had opaque and birefringent particles within macrophages, and examined particles contained silica, aluminum silicates, titanium dioxide, talc, and metals. CONCLUSIONS: : In symptomatic World Trade Center-exposed individuals, pathologic findings suggest a common exposure resulting in alveolar loss and a diverse response to injury

Pulmonary nodule detection and characterization continue to improve with technological advancements. The noninvasive methods available for assisting in nodule detection and for characterizing nodules as benign, malignant, or indeterminate will be discussed. Evidence-based guidelines will be reviewed to help guide the appropriate management of pulmonary nodules

Endovascular techniques have emerged as a minimally invasive alternative for the repair of the descending thoracic aorta, especially in high-risk patients. Multidetector computed tomography has a pivotal role, specifically in determining the candidacy or exclusion of patients for thoracic endovascular aortic repair and preoperative planning. In addition, multidetector computed tomography is used for follow-up assessment of the postsurgical aorta, so that potentially fatal complications can be correctly diagnosed and treated in a timely manner. In this pictorial review, we focus on the preoperative assessment of the pathologic aorta and evaluation after thoracic endovascular aortic repair