Faculty Bibliography

Objectives: To differentiate pulmonary tumor type by volumetric iodine quantification and texture analysis on dual-energy CT images.
Material(s) and Method(s): Radiology information system search for all contrast-enhanced DECT chest examinations from 1/1/2015-4/30/ 2018 was performed, filtering for those with pathology within 120 days, yielding 80 cases of pathologically-proven pulmonary lesions. 73 lesions meeting inclusion criteria were manually volumetrically segmented via open-source software using the low-kV DECT dataset. 3D-iodine quantification was achieved by mapping between high/low energy HU on a representative 2D-image, and applying to surrounding slices, with absolute iodine normalized to mid-descending aorta. Full Width Tenth Maximum was applied to each normalized iodine histogram, providing a single comprehensive measure of relative iodine concentration. Volumetric iodine values and first order texture features were assessed using Hoteling's T-squared multivariate analysis.
Result(s): 72 individuals (37 women, 35 men) with mean age 64 years were included. 44 primary, 25 metastatic, and 3 benign lesions were assessed; 22 with history of chemotherapy. Mean time between histopathologic sampling and imaging was 26 days. Mean, median and minimum volumetric iodine concentration were significant (P< 0.05) in distinguishing primary versus metastatic lesions, with P<0.01 for these measures between de novo primary and metastatic lesions. Metastatic lesions demonstrated higher mean iodine (1.2 mg/mL) in comparison to primary lesions (0.83 mg/mL). Mean and median 3D-iodine values significantly (P<0.05) differed between primary lung adenocarcinoma and squamous lesions (mean 0.95 mg/mL and 0.49 mg/mL, respectively). Skewness significantly differed between de novo versus treated primary (P=0.01), and metastatic versus primary lesions (P=0.03), and entropy between de novo primary and metastatic lesions (P<0.001), and treated versus non-treated metastases (P= 0.03).
Conclusion(s): Volumetric iodine quantification significantly differs between de novo primary versus metastatic, and primary lung adenocarcinoma versus squamous lesions. Texture features may also have a role in distinguishing tumor type and treatment response. Clinical Relevance Application: Potential role of DECT in distinguishing tumor type and treatment response

Background: Subsolid nodules account for 20% of lesions detected on CT lung cancer screening, and many are incidentally detected on routine CT exams. Persistent subsolid nodules may correlate with adenocarcinoma spectrum, though commonly are due to other etiologies, emphasizing the importance of accurate nodule characterization and management recommendations. This review will used a case-based approach to showcase how lesion description and management may differ from that of solid nodules, including application of Fleischner guidelines and discussion of management options. Educational Goals/Teaching Points: * Highlight technical pitfalls in evaluation of subsolid nodules * Highlight interpretive pitfalls in evaluation of subsolid nodules * Review differential considerations including adenocarcinoma spectrum: AAH, AIS, MIA, Invasive adenocarcinoma * Describe differential considerations beyond the adenocarcinoma spectrum, such as: * Neoplastic: lymphoma, metastatic disease, treatment response * Infectious/Inflammatory: organizing pneumonia, eosinophilic pneumonia, alveolar sarcoid, various infection, drug reaction * Adapt management guidelines to diverse clinical scenarios: age, multiplicity, baseline versus follow-up, incidental versus screening * Explain treatment options for subsolid adenocarcinoma lesions including emerging technology such as cryoablation
Conclusion(s): Subsolid nodules are commonly encountered clinically, with accurate interpretation based on avoiding technical pitfalls and providing relevant descriptors to differentiate actionable findings. Management guidelines and further steps must take into account nodule features, clinical risk factors, and patient specific considerations

Purpose: This study evaluated the comparative success of PD-L1 staining between surgical, endobronchial and transthoracic lung biopsy. Materials: This retrospective IRB approve study used our internal pathology database; we queried all cases with biopsy proven lung cancer for which PD-L1 analysis was performed from 5/1/2016 to 5/1/2018. Each procedure was reviewed for demographics, the type of biopsy, lesion size, lesion location, number of core biopsies, gauge of the core biopsy needle, depth from pleura, and complications. A correlation matrix was performed on all variable using a Person correlation. Significance was set at p<0.05. Result(s): 371 patients were included in this study; 289 samples were diagnosed as adenocarcinoma (or a variant of adenocarcinoma), 52 squamous cell, 18 non-small cell lung cancer NOS, 8 small cell lung cancer, 3 sarcomatoid carcinomas and 1 carcinoid. The cohort of 371 patients had a mean age of 67.7, (36-91); 52.5% (195/371) patients were female. 364 of the remaining 371 patients had successful analysis of PD-L1 (98.1%). These include 205 TTN, 136 endobronchial biopsies and 23 surgical biopsies. The characteristics of cases were; a mean size of 3.8 x 2.7 cm, a mean of 4.7+/- 1.9 (1-10) core biopsies were performed in these lesions, mean depth from the pleura was 1.9 cm (0-8.9). 10.0% (37/374) of these cases were complicated by pneumothorax. 14 patients were treated with surgical chest tube (two surgically placed chest tube was placed for a TTN) the remaining 12 surgical chest tubes were placed for surgical biopsies. 12 pigtail catheters were placed 9 for TTN (4.5%; 9/202) biopsies and two for surgical biopsies and one for endobronchial biopsy. The surgical rate of chest tube placement was 60.9% (12/23); TTN chest tube rate 4.4% (9/205) and the endobronchial biopsy chest tube rate was 0.75% (1/136). Two patients had alveolar hemorrhage both TTN, neither requi [Editorial Note: Sentence incomplete per submission. Missing text could not be recovered at press time] Conclusion(s): Transthoracic needle and endobronchial biopsies are robust methodology for the evaluation of tumor PD-L1 expression.

This pictorial essay presents cases of congenital coronary artery anomalies, including congenital anomalies of origin, course, and termination. Familiarity with atypical coronary anatomy and clinical presentation may facilitate appropriate diagnosis and management, particularly as cardiac and thoracic computed tomographic utilization increases.

OBJECTIVE:To assess causative factors, associated imaging findings, and CT course of round atelectasis (RA). MATERIALS AND METHODS/METHODS:We retrospectively reviewed CT reports for "round" or "rounded atelectasis" over a 5-year time frame. Patients with at least 2 CT scans a minimum of 6 months apart were included. Electronic medical records and clinical and imaging follow-up was reviewed for all cases. RESULTS:Study population included 50 individuals with mean age of 63 years, and 59 unique instances of RA. The most commonly associated etiologies were hepatic hydrothorax (26%, n = 13) and asbestos exposure (26%), followed by post-infectious pleural inflammation (22%), congestive heart failure (12%), and end stage renal disease (8%). RA was found in the right lower lobe in over half of cases (n = 30). Association with one or more pleural abnormality was identified in all cases, including thickening (88%), fluid (60%), or calcification (40%). Nearly one third (n = 19) demonstrated intra-lesional calcification. In those who underwent PET/CT (20%), lesions demonstrated an average SUV of 2.2 (range 0-7.8). CT course over mean follow up of 32 months (range 6-126 months), demonstrated RA to remain stable (n = 26) or decrease (n = 26) in size in the majority (88%) of cases. CONCLUSION/CONCLUSIONS:Round atelectasis may arise from diverse etiologies beyond asbestos, and will most often decrease or remain stable in size over serial exams. Accurate identification may obviate the need for added diagnostic interventions.

The incidental pulmonary nodule is commonly encountered when interpreting chest CTs. The management of pulmonary nodules requires a multidisciplinary approach entailing integration of nodule size and features, clinical risk factors, and patient preference and comorbidities. Guidelines have been issued for the management of both solid and subsolid nodules, with the Fleischner Society issuing revised guidelines in 2017. This article focuses on the CT imaging characteristics and clinical behavior of pulmonary nodules, with review of the current management guidelines that reflect this knowledge.

BACKGROUND: Coronary artery calcium (CAC) is often identified on routine chest computed tomography (CT). The purpose of our study was to evaluate whether ordinal scoring of CAC on non-gated, routine chest CT is an accurate predictor of Agatston score ranges in a community-based population, and in particular to determine the accuracy of an ordinal score of zero on routine chest CT. METHODS: Two thoracic radiologists reviewed consecutive same-day ECG-gated and routine non-gated chest CT scans of 222 individuals. CAC was quantified using the Agatston scoring on the ECG-gated scans, and using an ordinal method on routine scans, with a score from 0 to 12. The pattern and distribution of CAC was assessed. The correlation between routine exam ordinal scores and Agatston scores in ECG-gated exams, as well as the accuracy of assigning a zero calcium score on routine chest CT was determined. RESULTS: CAC was most prevalent in the left anterior descending coronary artery in both single and multi-vessel coronary artery disease. There was a strong correlation between the non-gated ordinal and ECG-gated Agatston scores (r = 0.811, p < 0.01). Excellent inter-reader agreement (k = 0.95) was shown for the presence (total ordinal score >/=1) or absence (total ordinal score = 0) of CAC on routine chest CT. The negative predictive value for a total ordinal score of zero on routine CT was 91.6% (95% CI, 85.1-95.9). Total ordinal scores of 0, 1-3, 4-5, and >/=6 corresponded to average Agatston scores of 0.52 (0.3-0.8), 98.7 (78.2-117.1), 350.6 (264.9-436.3) and 1925.4 (1526.9-2323.9). CONCLUSION: Visual assessment of CAC on non-gated routine chest CT accurately predicts Agatston score ranges, including the zero score, in ECG-gated CT. Inclusion of this information in radiology reports may be useful to convey important information on cardiovascular risk, particularly premature atherosclerosis in younger patients.

Appropriate placentation is critical to maternal and fetal outcomes. Abnormal placentation, including placenta previa and morbidly adherent placenta, is increasing in incidence and is associated with multiple risk factors including advanced maternal age and history of prior cesarean delivery. Magnetic resonance imaging (MRI) is increasingly used in assessing the type and extent of abnormal placentation, often leading to modifications in surgical approach. Here, we review the MRI features and appropriate reporting of placenta previa and the placenta accreta spectrum.