Lessons Learned from Peer Learning Conference in Cardiothoracic Radiology.

Medical errors may lead to patient harm and may also have a devastating effect on medical providers, who may suffer from guilt and the personal impact of a given error (second victim experience). While it is important to recognize and remedy errors, it should be done in a way that leads to long-standing practice improvement and focuses on systems-level opportunities rather than in a punitive fashion. Traditional peer review systems are score based and have some undesirable attributes. The authors discuss the differences between traditional peer review systems and peer learning approaches and offer practical suggestions for transitioning to peer learning conferences. Peer learning conferences focus on learning opportunities and embrace errors as an opportunity to learn. The authors also discuss various types and sources of errors relevant to the practice of radiology and how discussions in peer learning conferences can lead to widespread system improvement. In the authors' experience, these strategies have resulted in practice improvement not only at a division level in radiology but in a broader multidisciplinary setting as well. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2022.

Chest CT features are associated with poorer quality of life in acute lung injury survivors.

OBJECTIVES: Despite decreasing mortality rates in acute lung injury, studies of long-term physical function in acute lung injury survivors have consistently reported poorer quality of life persisting years into recovery for reasons that are not completely understood. We sought to determine if pulmonary dysfunction is independently associated with functional impairment among acute lung injury survivors and to determine if high-resolution computed tomography could be used to predict its development. DESIGN: Secondary analysis of data from a randomized controlled trial in acute lung injury. SETTING: ICUs at three academic medical centers. PATIENTS: Patients diagnosed with acute lung injury who had high-resolution computed tomography scans performed at 14 and/or 180 days after diagnosis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: An objective radiologic scoring system was used to quantify patterns present on chest high-resolution computed tomography obtained at 14 and 180 days in patients with acute lung injury. These scores were correlated in univariable and multivariable analyses with pulmonary function testing and quality of life survey data obtained at 180 days. Eighty-nine patients had evaluable data at day 14, and 47 at 180 days. At 180 days, increased radiologic scores for reticulation were associated with a decreased total lung capacity, forced vital capacity, and diffusing capacity for carbon monoxide (p values all < 0.002). Decrements in quality of life attributable to pulmonary dysfunction were most strongly associated with higher radiologic scores. Additionally, radiologic scores at 14 days independently predicted poorer quality of life at 180 days, accounting for age, severity of illness, pneumonia as the acute lung injury risk factor, and length of time on mechanical ventilation. CONCLUSIONS: Among survivors of acute lung injury, increasing chest high-resolution computed tomography involvement correlated with restrictive physiology and poorer health-related quality of life, implicating pulmonary dysfunction as a potential contributor to activity limitation in these patients.

"Sweet spot" for endoleak detection: optimizing contrast to noise using low keV reconstructions from fast-switch kVp dual-energy CT.

OBJECTIVE: To assess endoleak detection and conspicuity using low-kiloelectron volt (keV) monochromatic reconstructions of single-source (fast-switch kilovolt [peak]) dual-energy data sets. METHODS: With approval of the institutional review board, multiphasic dual-energy computed tomographic (CT) scans for aortic endograft surveillance were retrospectively reviewed for 39 patients. Two abdominal radiologists each performed 2 separate reading sessions, at 55-keV and standard 75-keV reconstruction, respectively. The readers tabulated endoleak presence, conspicuity on 1-to-5 scale, and type overall and in arterial and venous phases. Originally, dictated reports in medical records were used as criterion standard. RESULTS: Original dictations identified 19 endoleaks (9 abdominal and 10 thoracic), 13 of which were type II. The blinded readers (R1 and R2) exhibited good to very good intraobserver and interobserver agreement. Endoleak detection was higher at 55 keV than at 75 keV (sensitivity, 100% (95% confidence interval [CI], 82.4%-100.0%) and 84.2% (95% CI, 60.4-96.6%) at 55 keV vs 79% (95% CI, 54.4-94.0%) and 68.4% (95% CI, 43.5%-87.4%) at 75 keV in venous phase). Further, endoleak conspicuity ratings (where original dictation showed positive leak) were higher at 55 keV than at 75 keV, which was a significant difference for R2 in the overall ratings (P = 0.03) and for both readers in the venous phase ratings (R1, P = 0.01; R2, P = 0.004). There was no difference in endoleak type characterization between the kiloelectron volt levels. CONCLUSION: Sensitivity for endoleak detection and overall endoleak conspicuity ratings were both higher at 55 keV than 75 keV, favoring the inclusion of a lower-energy monochromatic reconstruction for endoleak surveillance protocols with dual-energy computed tomography.

The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI): a completed reference database of lung nodules on CT scans.

PURPOSE: The development of computer-aided diagnostic (CAD) methods for lung nodule detection, classification, and quantitative assessment can be facilitated through a well-characterized repository of computed tomography (CT) scans. The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI) completed such a database, establishing a publicly available reference for the medical imaging research community. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process. METHODS: Seven academic centers and eight medical imaging companies collaborated to identify, address, and resolve challenging organizational, technical, and clinical issues to provide a solid foundation for a robust database. The LIDC/IDRI Database contains 1018 cases, each of which includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experienced thoracic radiologists. In the initial blinded-read phase, each radiologist independently reviewed each CT scan and marked lesions belonging to one of three categories ("nodule > or =3 mm," "nodule <3 mm," and "non-nodule > or =3 mm"). In the subsequent unblinded-read phase, each radiologist independently reviewed their own marks along with the anonymized marks of the three other radiologists to render a final opinion. The goal of this process was to identify as completely as possible all lung nodules in each CT scan without requiring forced consensus. RESULTS: The Database contains 7371 lesions marked "nodule" by at least one radiologist. 2669 of these lesions were marked "nodule > or =3 mm" by at least one radiologist, of which 928 (34.7%) received such marks from all four radiologists. These 2669 lesions include nodule outlines and subjective nodule characteristic ratings. CONCLUSIONS: The LIDC/IDRI Database is expected to provide an essential medical imaging research resource to spur CAD development, validation, and dissemination in clinical practice.

Extra Z-axis coverage at CT imaging resulting in excess radiation dose: frequency, degree, and contributory factors.

OBJECTIVE: To assess the degree of extra scanning beyond the prescribed anatomic boundaries for thoracic and body computed tomographic (CT) scans and to identify associated factors. METHODS: For 442 consecutive chest, abdomen, and/or pelvis CT examinations, the length of extra scanning beyond the prescribed anatomic boundaries was determined. Examinations were grouped according to the locations/types of the prescribed boundaries and compared with regard to length of extra scanning. RESULTS: Of 442 CT examinations, 438 (99%) included extraneous imaging, showing a mean excess scanning length of 43.2 mm per examination (range, 0-180 mm). Significantly more extraneous imaging was performed when soft tissue or vascular structures defined anatomic boundaries compared to when osseous (P < 0.001) or air/soft tissue interfaces (P < 0.0001) defined the boundaries. The average percent of total scan dose attributable to extra imaging was 8.64% to 10.38%. CONCLUSIONS: Computed tomographic scanning beyond the prescribed anatomic boundaries occurs commonly, resulting in moderate extra radiation dose.

Aortic endograft surveillance: use of fast-switch kVp dual-energy computed tomography with virtual noncontrast imaging.

OBJECTIVE: To assess endoleak detection and patients' radiation exposure using fast-switch peak kilovoltage (kVp) dual-energy computed tomography (DECT) with virtual noncontrast (VNC) imaging. METHODS: Institutional review board approved retrospective review of triphasic CTs for endograft follow-up: single-energy true noncontrast (TNC) and dual-energy arterial- and venous-phase postcontrast scans on GE HD-750 64-detector scanners. Iodine-subtracted VNC images generated from dual-energy data. Two radiologists (VNC readers) independently performed 2 reading sessions without TNC images: (1) arterial and VNC and (2) venous and VNC. Interrater agreement, leak detection sensitivity, and dose estimates were calculated. RESULTS: Original dictations described 24 endoleaks in 78 scans. Virtual noncontrast reader agreement was high (κ = 0.78-0.79). Virtual noncontrast reader ranges for sensitivity and negative predictive value for leak detection were 87.5% to 95.8% and 94.0% to 98.0% in venous phase. Dose reduction estimate was 40% by eliminating one phase and 64% by eliminating 2 phases of imaging. CONCLUSION: Virtual noncontrast images from fast-switch peak kilovoltage DECT data can substitute for TNC imaging in the postendograft aorta, conferring substantial dose reduction. Eliminating 1 of 2 postcontrast phases further reduces dose, with greater negative predictive value for leak detection in the venous versus the arterial phase. Thus, the use of a monophasic venous-phase DECT with VNC images is suggested for long-term endograft surveillance in stable patients.

Traumatic aortic injury: computerized tomographic findings at presentation and after conservative therapy.

OBJECTIVE: To determine the computerized tomographic (CT) findings in traumatic aortic injury (TAI) at presentation and after conservative management. METHODS: Institutional review board-approved retrospective review of trauma registry during a 6-year period identified class 1 or 2 trauma patients with TAI. The CT findings were correlated with patient outcome. RESULTS: Forty-eight of 3350 patients had TAI. Seven had TAI limited to the abdominal aorta. Twenty-nine of 48 had early (12) or delayed (17) aortic repair. Common abnormalities were pseudoaneurysms (69%) and intramural hematoma (IMH) (65%). Forty-one of 48 TAI were confirmed on endovascular imaging or surgery. Subsequent CT was available in those who had delayed repair (n = 9) or conservative management (10) and showed stable pseudoaneurysms with resolving IMH (n = 11), resolving IMH (n = 4), intimal flap (n = 2), aortic thrombus (n = 1), and dissection (n = 1). CONCLUSIONS: Traumatic aortic injury is rare. It commonly involves thoracic aorta with pseudoaneurysm and IMH. Significant TAI in stable patients remains stable on follow-up imaging. Minor TAI may resolve with conservative therapy.

Ulcerlike projections developing in noncommunicating aortic dissections: CT findings and natural history.

OBJECTIVE: Aortic ulcerlike projections are focal, contrast-filled outpouchings projecting from the aortic lumen. Our aim was to document the CT findings and natural history of ulcerlike projections developing in patients with preexisting noncommunicating aortic dissection, including intramural hematoma or false lumen thrombosis. MATERIALS AND METHODS: By searching the radiology information system, we found 38 ulcerlike projections arising in an underlying noncommunicating aortic dissection that were identified at CT in 24 patients. Clinical factors were determined from patient records. CT scans were reviewed to determine aortic pathology type and appearance time of ulcerlike projections and to measure the diameters of the aorta and ulcerlike projections for comparison over time. Complications were defined as an increase of at least 20% in the diameters of the ulcerlike projections or aorta, the need for surgical repair, or both. Comparisons of ulcerlike projections with and without complications were performed using various statistical tests. RESULTS: The underlying aortic disease of the 38 ulcerlike projections was intramural hematoma in 26, false lumen thrombosis in nine, and unknown in three. The mean time of ulcerlike projection appearance was 2.4 months (SD, 1.8) for intramural hematoma and 19.3 months (SD, 18.1) for false lumen thrombosis. Nine of the 28 ulcerlike projections with follow-up scans showed stability, size decrease, or resolution; 10 increased in size; and nine were incorporated into an expanded aortic lumen. Four of 36 ulcerlike projections with imaging or clinical follow-up (or both) required surgical repair. The only clinical or imaging feature significantly associated with the development of complications was false lumen thrombosis (p = 0.04). CONCLUSION: Ulcerlike projections forming in noncommunicating dissections may enlarge over time, although they rarely require surgical repair. Given the potential for critical complications, these lesions should be followed with serial CT scans.

Distinguishing acute from chronic aortic dissections using CT imaging features.

The aim was to compare computed tomography (CT) features in acute and chronic aortic dissections (AADs and CADs) and determine if a certain combination of imaging features was reliably predictive of the acute versus chronic nature of disease in individual patients. Consecutive patients with aortic dissection and a chest CT scan were identified, and 120 CT scans corresponding to 105 patients were reviewed for a variety of imaging features. Statistical tests assessed for differences in the frequency of these features. A predictive model was created and tested on an additional 120 CT scans from 115 patients. Statistically significant features of AAD included periaortic confluent soft tissue opacity, curved dissection flap, and highly mobile dissection flap, and features of CAD included thick dissection flap, false lumen (FL) outer wall calcification, FL thrombus, dilated FL, and tear edges curling into the FL. The model predicted the chronicity of a dissection with an area under the curve of 0.98 (CI 0.98-1.00). AADs and CADs demonstrated significantly different CT imaging features.

Pulmonary nodule volumetric measurement variability as a function of CT slice thickness and nodule morphology.

OBJECTIVE: The purpose of our study was to assess differences in volumetric measurements of pulmonary nodules obtained using different CT slice thicknesses; correlate these differences with nodule size, shape, and margination; and compare measurements generated by two different software packages. MATERIALS AND METHODS: Seventy-five individual nodules identified on 29 lowdose, unenhanced, MDCT chest examinations were selected for volumetric analysis. Each image data set was reconstructed in three ways (slice thickness/reconstruction interval): 1.25 mm/0.625 mm, 2.5 mm/2 mm, and 5 mm/2.5 mm. Volumetric measurements were made on all 75 nodules at 1.25- and 2.5-mm slice thicknesses and on 57 of 75 nodules at the 5-mm thickness using Volume Analysis software. For 69 of 75 nodules, measurements were obtained on 1.25- and 2.5-mm-thick sections using a different commercially available software system, LN500 R2 software. Volume variability between different slice thicknesses was correlated with nodule diameter, shape, and margination using multiple linear regression. Percent differences between measurements obtained with the two software systems were calculated. Significance of relative volume differences between slice thicknesses and software packages was assessed using a one-sample Student's t-test. RESULTS: Although statistically significant differences in volumes between different section thicknesses were seen only for the tiny nodule size group, many individual nodules showed substantial volume variation. Significant differences were seen in nodule volume variability for smaller nodules (3-10 mm) compared with larger nodules (> or = 11 mm) (p < 0.0001), as well as spiculated compared with smooth nodules, within a single size group (p < 0.05). No effect of nodule shape (round vs elongated) was noted. Statistically significant differences in measurements obtained with the two software systems were seen only with 2.5-mm-thick sections (p = 0.001). CONCLUSION: CT slice thickness variation resulted in significant differences in volume measurements for tiny nodules. A spiculated margin was shown to have a significant effect on nodule volume variability within a single size group. Use of different software packages resulted in significant volume measurement differences at the 2.5-mm CT slice thickness.

CT findings following thoracic aortic surgery.

Complications following thoracic aortic graft surgery are rare. They are not always clinically apparent and may occasionally be detected at computed tomography (CT) even in asymptomatic patients. Normal postoperative findings that may simulate complications include graft kinks, graft side branches, felt pledgets or rings, small amounts of low-attenuation perigraft material, native aortic wraps, and bovine pericardial wraps. Postoperative complications include anastomotic dehiscence and graft infection, which may lead to perigraft hematomas, pseudoaneurysms, abscesses, or fistulas. At CT, these complications may manifest as abnormally large collections of low-attenuation perigraft material, contrast material extravasation, perigraft gas collections, or fistulas to adjacent structures. Familiarity with both normal and abnormal postoperative CT findings and knowledge of the surgical technique used are essential to avoid misdiagnosing normal findings and to correctly diagnose potentially life-threatening complications. Following graft surgery, surveillance imaging may be needed, since the time of onset of complications seems highly variable.

Pelvic artery aneurysm screening provides value in patients with thoracic aortic aneurysms.

Approximately » of patients with thoracic aortic aneurysms (TAAs) have concomitant abdominal aortic aneurysms (AAAs), thereby justifying the addition of an abdominal CT scan to a chest CT scan in patients with a newly diagnosed or suspected TAA. However, the prevalence of pelvic artery aneurysms (PAAs) in these patients is unknown. The purpose of this study was to determine the prevalence of PAAs in patients with TAAs and to assess what patient specific factors were associated with PAAs, thereby providing insight into the usefulness of pelvic imaging in TAA patients. Consecutive non-operated patients seen in Cardiac Surgery clinic between 2008 and 2013 with a TAA and a CT scan of the chest/abdomen/pelvis were included. Scans of 371 patients were evaluated for PAAs using threshold diameters of 20 and 15 mm for common iliac artery aneurysms (CIAs) and internal iliac artery aneurysms (IIAs), respectively, on 3D analysis. The prevalence of PAAs was determined and multiple logistic regression was used to identify associated risk factors. 41 of 371 (11.1%) patients with a TAA had at least one PAA. Factors showing positive associations with PAAs included increased age (p = 0.0004), male gender (p = 0.0007), descending TAA location (p = 0.0024) and presence of an AAA (p < 0.0001). The results of our study suggest that the addition of pelvic imaging for PAA screening in patients undergoing an initial CT scan of the chest and abdomen for a TAA is valuable, particularly in patients with the following demographics: age ≥65, male gender, descending TAA location, and/or known AAA.

Proximal thoracic aortic diameters: transesophageal-echocardiography- versus computed-tomography-derived measurements.

PURPOSE: The purpose of the study was to compare proximal aortic measurements from electrocardiogram-gated computed tomography (CT) to transesophageal echocardiography (TEE) and to evaluate differences in cusp-cusp and cusp-commissure CT measurements of sinus of Valsalva (SOV). METHODS: This retrospective study (n=25) compared aortic diameters from CT using manual double-oblique multiplanar reformats (MPRs) and semiautomatic centerline method to TEE. RESULTS: CT MPR and centerline measurements were higher than TEE for sinotubular junction and ascending aorta. At SOV, cusp-cusp diameters (MPR and centerline methods) and cusp-commissure measurement (centerline method) were larger than TEE. CONCLUSIONS: Aortic measurements were larger on CT than TEE. Precise difference depended on location and measurement technique.

Evaluation for abdominal aortic aneurysms is justified in patients with thoracic aortic aneurysms.

Aortic aneurysms are a significant cause of mortality, and the presence of multiple aneurysms may affect treatment plans. The purpose of this study was to determine the frequency of abdominal aortic aneurysms (AAAs) in patients with thoracic aortic aneurysms (TAAs) and to establish whether patient specific factors, such as gender and comorbidities, influenced the frequency of AAAs, thereby indicating if and when abdominal aortic evaluation is justified. Electronic medical records were reviewed from 1000 patients with a computed tomography (CT) angiogram of the chest and abdomen and a clinical diagnosis of TAA from Cardiac Surgery clinic between 2008 and 2013. 538 patients with history of aortic intervention, dissection, rupture or trauma were excluded. The frequency of AAAs among the 462 remaining patients was established, and statistical analysis was used to elucidate differences in frequency based on age, gender, comorbidities, and TAA location. Overall, 104 of 462 (22.5 %) patients with a TAA also had an AAA. There were significant differences in the frequency of AAA based on TAA location, age, and comorbidities. The following comorbidities showed positive associations with AAA using logistic regression analysis: age ≥65 (P < 0.0001; OR 30.1; CI 7.14-126.61), smoking history (P < 0.0001; OR 4.1; 2.35-7.30), and hypertension (P = 0.024; OR 2.1; CI 1.11-4.16). Aneurysms in the proximal/mid descending (P < 0.0001; OR 4.96; CI 2.32-10.61) and diaphragm level (P < 0.0001; OR 38.4; CI 14.71-100.15) of the aorta also showed a positive association with AAAs when adjusted for age and gender. AAA screening in patients with TAA is a reasonable, evidence-based option regardless of the TAA location, with the strongest support in patients >age 55, with systemic hypertension, a smoking history and/or a TAA in the descending thoracic aorta.

CT-based definition of thoracic lymph node stations: an atlas from the University of Michigan.

PURPOSE: Accurate delineation of the mediastinal and hilar lymph node regions is essential for a reproducible definition of target volumes used in conformal irradiation of non-small-cell lung cancer. The goal of this work was to generate a consensus to delineate these nodal regions based on definitions from the American Joint Committee on Cancer. METHODS AND MATERIALS: A dedicated thoracic radiologist, thoracic surgeon, medical physicist, and three radiation oncologists were gathered to generate a three-dimensional radiologic description for the mediastinal and hilar nodal regions on axial CT scans. This paper proposes an atlas of most of the lymph node stations described by Mountain and Dresler. RESULTS: The CT boundaries of lymph node stations 1-2, 3, 4, 5, 6, 7, 8, 10-11 were defined on axial CT, along with image illustrations. CONCLUSION: These CT-based illustrative definitions will provide guidelines for clinical practice and studies evaluating incidental radiation in radiotherapy. Studies are ongoing at the University of Michigan to measure quantitatively the incidental nodal radiation received by patients with non-small-cell lung cancer.

Interobserver and intraobserver variability in the assessment of pulmonary nodule size on CT using film and computer display methods.

RATIONALE AND OBJECTIVES: A critical element in determining biologic behavior of pulmonary nodules is volume and temporal volume change. We evaluate variability in nodule volume among readers and measuring methods. MATERIALS AND METHODS: 55 small (<2 cm) lung nodules were measured in long- and short-axis dimensions independently by 4 radiologists, using 3 methods: 1) hard copy, 2) GE Advantage Windows workstation (GE Healthcare, Milwaukee, WI), 3) Siemens IMACS workstation (Siemens Medical Systems, Iselan, NJ). Nodule margin was recorded as smooth, lobulated, or spiculated. Volume was calculated from diameter measurements. Variability in nodule volume was evaluated within each reader, between readers, and across measurement tools. RESULTS: Mean nodule short-axis diameter was 5.3 mm; mean long-axis diameter 7.2 mm. There was statistically significant variation among readers and measurement method for nodule volume. Volume was significantly larger using hard-copy measurements (51.9%-54.1% variation; P < .0001) than either workstation, and not different between workstations. There was greater intraobserver variability in volume using the hard-copy method, and no difference between workstation methods. Volumes based on measurements from one reader were consistently lower than those from other readers (P = < .001, .003, and .02); volume was consistently larger for another reader (P < .0001, .03, and .12). Reader agreement for nodule margin was good to excellent. CONCLUSION: Considerable interobserver and intraobserver variability in measuring nodules exists using hard-copy and computer tools. Since a small change in diameter indicates a much larger change in volume, this may be significant when using early repeat CT to follow small pulmonary nodules. Computer-aided diagnostic tools that reproducibly measure nodule volume are strongly needed.

Detection of fibroproliferation by chest high-resolution CT scan in resolving ARDS.

BACKGROUND: In ARDS, the extent of fibroproliferative activity on chest high-resolution CT (HRCT) scan has been reported to correlate with poorer short-term outcomes and pulmonary-associated quality of life. However, clinical factors associated with HRCT scan fibroproliferation are incompletely characterized. We questioned if lung compliance assessed at the bedside would be associated with fibroproliferation on HRCT scans obtained during the resolution phase of ARDS. METHODS: We used data from a published randomized, controlled clinical trial in ARDS. All patients were cared for using a low tidal volume strategy. Demographic data and ventilator parameters were examined in association with radiologic scores from chest HRCT scans obtained 14 days after diagnosis. RESULTS: Data from 82 patients with ARDS were analyzed. Average static respiratory compliance over the first 14 days after diagnosis was inversely associated with chest HRCT scan reticulation (ρ = -0.46); this relationship persisted in multivariable analysis including APACHE (Acute Physiology and Chronic Health Evaluation) II scores, initial Pao2/Fio2, pneumonia diagnosis, and ventilator days. Average static respiratory compliance was also lower among patients with bronchiectasis at day 14 (P = .007). Initial static respiratory compliance obtained within the first day after ARDS diagnosis was correlated inversely with the presence of HRCT scan reticulation (ρ = -0.38) and was lower among patients who demonstrated bronchiectasis on the day 14 HRCT scan (P = .008). CONCLUSIONS: In patients with ARDS, diminished lung compliance measured bedside was associated with radiologic fibroproliferation 14 days post diagnosis. Establishing factors that predispose to development of excessive fibroproliferation with subsequent confirmation by chest HRCT scan represents a promising strategy to identify patients with ARDS at risk for poorer clinical outcomes.

Incidental, subsolid pulmonary nodules at CT: etiology and management.

Pulmonary nodules, both solid and subsolid, are common incidental findings on computed tomography (CT) studies. Subsolid nodules (SSNs) may be further classified as either pure ground-glass nodules or part-solid nodules. The differential diagnosis for an SSN is broad, including infection, organizing pneumonia, inflammation, hemorrhage, focal fibrosis, and neoplasm. Adenocarcinomas of the lung are currently the most common type of lung cancer, representing 30-35% of all primary lung tumors, and the subtype of bronchioloalveolar cell carcinoma (BAC) commonly presents as an SSN. In 2011, a new classification system for lung adenocarcinomas was proposed by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. An important feature of the new system is the relinquishment of the term BAC in favor of more specific histologic subtypes. It has been reported that these subtypes are associated with characteristic CT findings. This article reviews the new classification system of lung adenocarcinomas, discusses and illustrates the associated CT findings, and outlines the current recommendations for further diagnosis, treatment, and follow-up of SSNs based on computed tomography findings.

Proximal thoracic aortic diameter measurements at CT: repeatability and reproducibility according to measurement method.

AIM: To determine the variability in CT measurements of proximal thoracic aortic diameters obtained using double-oblique short axis and semiautomatic centerline analysis techniques. Institutional review board approval, with waiver of informed consent, was obtained for this HIPAA-compliant, retrospective study. Cardiac gated thoracic aortic CT scans were evaluated in 25 patients. Maximum aortic diameter measurements at the annulus, sinuses, sinotubular junction and ascending aorta were generated using double-oblique short axis and semiautomatic centerline analysis techniques. Intraobserver and interobserver variability and variability between techniques were assessed using the Wilcoxon signed rank test, Spearman's correlation coefficients and Bland-Altman plots. Mean intraobserver diameter differences using double oblique views ranged from -0.3 to 0.6 mm. The 95 % confidence interval for difference in diameters was ±2.4 to ±5.1 mm for radiologist #1 and ±2.6 to ±5.2 mm for radiologist #2, depending on location. Mean intraobserver diameter differences using centerline analysis ranged from 0.2 to 2.3 mm, and the 95 % confidence interval for difference in diameters was ±2.0 to ±4.6 mm, depending on location. Significant interobserver differences were seen for both double oblique views and centerline analysis. Measurements obtained using the two methods were strongly correlated (r = 0.81-0.99), although they were consistently larger using centerline analysis (95 % confidence interval, ±1.8 to ±3.2 mm). Although measurement variability of the proximal thoracic aorta was generally low using double oblique and centerline analysis techniques, differences of up to approximately 5 mm in diameter occurred within the 95 % confidence interval. Neither technique was clearly more reliable than the other.

Imaging in thoracic oncology: case studies from Multidisciplinary Thoracic Tumor Board: (part 2 of 2 part series).

Multidisciplinary tumor board conferences foster collaboration among health care providers from a variety of specialties and help to facilitate optimal patient care. Generally, the clinical questions revolve around the best options for establishing a diagnosis, staging the disease and directing treatment. This article describes and illustrates the clinical scenarios of three patients who were presented at our thoracic Tumor Board, focusing on management issues and the role of imaging. These patients had invasive thymoma; concurrent small cell lung cancer and non-small cell lung cancer; and esophageal cancer with celiac lymph node metastases, respectively.