The calcified lung nodule: What does it mean?

New insights into imaging of pulmonary metastases from extra-thoracic neoplasms

The lung is one of the most common sites of metastases from extra-thoracic neoplasms. Lung metastases can show heterogeneous imaging appearance, thus mimicking a wide range of lung diseases, from benign lesions to primary lung cancer. The proper interpretation of pulmonary findings is crucial for prognostic assessment and treatment planning, even to avoid unnecessary procedures and patient anxiety. For this purpose, computed tomography (CT) is one of the most used imaging modalities. In the last decades, cancer patients' population has steadily increased and, due to the widespread application of CT for staging and surveillance, the detection of pulmonary nodules has raised, making their characterization and management an urgent and mostly unsolved problem for both radiologists and clinicians. This review will highlight the pathways of dissemination of extra-thoracic tumours to the lungs and the heterogeneous CT imaging appearance of pulmonary metastases, providing useful clues to properly address the diagnosis. Furthermore, we will deal with the promising applications of radiomics in this field. Finally, a focus on the hot-topic of pulmonary nodule management in patients with extra-thoracic neoplasms (ETNs) will be discussed.

Incidental Pulmonary Nodules: Differential Diagnosis and Clinical Management

BACKGROUND

According to data from the USA, the incidence of incidentally discovered pulmonary nodules is 5.8 per 100 000 person- years for women and 5.2 per 100 000 person-years for men. Their management as recommended in the pertinent guidelines can substantially improve clinical outcomes. More than 95% of all pulmonary nodules revealed by computerized tomography (CT) are benign, but many cases are not managed in conformity with the guidelines. In this article, we summarize the appropriate clinical approach and provide an overview of the pertinent diagnostic studies and when they should be performed.

METHODS

This review is based on relevant publications retrieved by a selective search in PubMed. The authors examined Englishlanguage recommendations issued since 2010 for the management of pulmonary nodules, supplemented by comments from the German lung cancer guideline.

RESULTS

In general, the risk that an incidentally discovered pulmonary nodule is malignant is low but rises markedly with increasing size and the presence of risk factors. When such a nodule is detected, the further recommendation, depending on size, is either for follow-up examinations with chest CT or else for an extended evaluation with positron emission tomography-CT and biopsy for histology. The diagnostic evaluation should include consideration of any earlier imaging studies that may be available as an indication of possible growth over time. Single nodules measuring less than 6 mm, in patients with few or no risk factors, do not require any follow-up. Lung cancer is diagnosed in just under 10% of patients with a nodule measuring more than 8 mm.

CONCLUSION

The recommendations of the guidelines for the management of incidentally discovered pulmonary nodules are intended to prevent both overand undertreatment. If a tumor is suspected, further care should be provided by an interdisciplinary team.

Histology of pulmonary tuberculosis in a 19th-century mummy from Comiso (Sicily, Italy)

OBJECTIVE

The aim of this study is to investigate potential evidence of tuberculosis in mummified remains.

MATERIALS

The natural mummy of an anonymous friar from the mortuary chapel of the church of Santa Maria della Grazia in Comiso (Sicily) METHODS: The mummy was studied through macroscopic examination; tissue sampling was conducted through breaches in the dorsal surface of the thorax. Radiological, histological and immunohistochemical analyses were performed on the pulmonary parenchyma.

RESULTS

The mummified remains are those of an adult male approximately 25-45 years old. In the left lung, 7 intra parenchymal calcified nodules were detected. The fibrocalcific nodules showed some lacunae surrounded by fibrous tissue containing amorphous necrotic, most probably caseous, material.

CONCLUSIONS

These findings are compatible with a chronic infectious-inflammatory disease, likely a calcification of a previous Ghon complex of an apical nodular tuberculosis.

SIGNIFICANCE

Our study supports the great spread of the disease in the 19th century; a time when it reached its maximum peak in Europe.

LIMITATIONS

Molecular investigations failed to detect traces of Mycobacterium tuberculosis DNA in the sample.

SUGGESTIONS FOR FURTHER RESEARCH

The investigation on the mummies from Comiso is still in progress, and further analyses will potentially provide paleopathological data on this community of Modern Age which could be integrated with historical and archival sources.

In Situ Lung Dust Analysis by Automated Field Emission Scanning Electron Microscopy With Energy Dispersive X-ray Spectroscopy: A Method for Assessing Inorganic Particles in Lung Tissue From Coal Miners

CONTEXT.—

Overexposure to respirable coal mine dust can cause severe lung disease including progressive massive fibrosis (PMF). Field emission scanning electron microscopy with energy dispersive x-ray spectroscopy (FESEM-EDS) has been used for in situ lung dust particle analysis for evaluation of disease etiology. Automating such work can reduce time, costs, and user bias.

OBJECTIVE.—

To develop and test an automated FESEM-EDS method for in situ analysis of inorganic particles in coal miner lung tissue.

DESIGN.—

We programmed an automated FESEM-EDS procedure to collect particle size and elemental data, using lung tissue from 10 underground coal miners with PMF and 4 control cases. A statistical clustering approach was used to establish classification criteria based on particle chemistry. Data were correlated to PMF/non-PMF areas of the tissue, using corresponding brightfield microscopy images. Results for each miner case were compared with a separate corresponding analysis of particles recovered following tissue digestion.

RESULTS.—

In situ analysis of miner tissues showed higher particle number densities than controls and densities were generally higher in PMF than non-PMF areas. Particle counts were typically dominated by aluminum silicates with varying percentages of silica. Compared to digestion results for the miner tissues, in situ results indicated lower density of particles (number per tissue volume), larger size, and a lower ratio of silica to total silicates-probably due to frequent particle clustering in situ.

CONCLUSIONS.—

Automated FESEM-EDS analysis of lung dust is feasible in situ and could be applied to a larger set of mineral dust-exposed lung tissues to investigate specific histologic features of PMF and other dust-related occupational diseases.

Navigating the Maze: Exploring Non-Oncological Complexities in Non-Small-Cell Lung Cancer

Pulmonary oncological pathologies are an important public health problem and the association with other pulmonary lesions may pose difficulties in diagnosis and staging or require different treatment options. To address this complexity, we conducted a retrospective observational study at the Marius Nasta Institute of Pneumophthisiology, Bucharest, Romania. Our study focused on patients admitted in 2019 with non-small-cell lung carcinoma and associated pulmonary lesions identified through surgical resection specimens. Among the 314 included patients, multiple pulmonary nodules were observed on macroscopic examination, with 12% (N = 37) exhibiting nonmalignant etiologies upon microscopic examination. These findings underscore the challenge of preoperative staging. Patients with coexisting nonmalignant lesions were similar in age, smoking habits, and professional or environmental exposure by comparison with those who presented only malignant lesions. The presentation of coexisting malignant and nonmalignant lesions may pose difficulties in diagnosing and staging pulmonary cancer.

Primary pulmonary synovial sarcoma with delayed diagnosis in a 69-year-old man: A case report

RATIONALE

Primary pulmonary synovial sarcoma is a rare malignant pulmonary tumor accompanied by calcifications in approximately 15% of cases. These calcifications usually have a fine, stippled appearance; coarse shapes have seldom been reported. Moreover, the presence of coarse calcifications often suggests benign tumors, which vastly differ in treatment. We present a rare case of primary pulmonary sarcoma with coarse intratumoral calcifications, the diagnosis of which was delayed because of its radiologic appearance.

PATIENT CONCERNS

A computed tomography (CT) scan of a 69-year-old man with right upper quadrant (RUQ) pain revealed an incidental mass at the base of the right lower lobe, the margin of which was not well described with respect to the liver, and intratumoral coarse calcification was noted. Initially, the lesion was believed to be hepatic, and magnetic resonance imaging (MRI) was performed. Based on its imaging features, the mass was thought to be a pulmonary lesion, and a preliminary diagnosis of a benign lesion, such as a hamartoma or granuloma, was made. Four months after the initial CT scan, the patient's RUQ pain had aggravated; however, no change in the mass was observed on follow-up CT.

DIAGNOSIS

The final diagnosis was primary pulmonary sarcoma, proven by surgical biopsy.

INTERVENTIONS

Wedge resection of the right lower lobe was performed, and the patient received adjuvant chemotherapy.

OUTCOMES

The patient's RUQ pain improved, and no recurrence or metastasis has been reported to date.

LESSONS

This case describes a rare presentation of a primary pulmonary synovial sarcoma with coarse intratumoral calcifications and the MRI features of the lesion. Intratumoral coarse calcifications often suggest benign lesions, such as hamartomas or post-inflammatory granulomas; however, as malignant lesions cannot be completely excluded, other radiologic and clinical features should be considered carefully. Focal areas of enhancement and eccentric calcification distribution might suggest malignant lesions such as primary pulmonary synovial sarcoma. Furthermore, despite not being used routinely, MRI scans might be helpful because advanced MRI techniques, such as diffusion-weighted imaging, can help distinguish malignant lesions from benign lesions. If the clinical course of a patient suggests malignancy, a more aggressive biopsy strategy should be considered.

Stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities on CT

High-attenuation pulmonary abnormalities are commonly seen on CT. These findings are increasingly encountered with the growing number of CT examinations and the wide availability of thin-slice images. The abnormalities include benign lesions, such as infectious granulomatous diseases and metabolic diseases, and malignant tumors, such as lung cancers and metastatic tumors. Due to the wide spectrum of diseases, the proper diagnosis of high-attenuation abnormalities can be challenging. The assessment of these abnormal findings requires scrutiny, and the treatment is imperative. Our proposed stepwise diagnostic algorithm consists of five steps. Step 1: Establish the presence or absence of metallic artifacts. Step 2: Identify associated nodular or mass-like soft tissue components. Step 3: Establish the presence of solitary or multiple lesions if identified in Step 2. Step 4: Ascertain the predominant distribution in the upper or lower lungs if not identified in Step 2. Step 5: Identify the morphological pattern, such as linear, consolidation, nodular, or micronodular if not identified in Step 4. These five steps to diagnosing high-attenuation abnormalities subdivide the lesions into nine categories. This stepwise radiologic diagnostic approach could help to narrow the differential diagnosis for various pulmonary high-attenuation abnormalities and to achieve a precise diagnosis.Critical relevance statement Our proposed stepwise diagnostic algorithm for high-attenuation pulmonary abnormalities may help to recognize a variety of those high-attenuation findings, to determine whether the associated diseases require further investigation, and to guide appropriate patient management. Key points • To provide a stepwise diagnostic approach to high-attenuation pulmonary abnormalities.• To familiarize radiologists with the varying cause of high-attenuation pulmonary abnormalities.• To recognize which high-attenuation abnormalities require scrutiny and prompt treatment.

High risk lung nodule: A multidisciplinary approach to diagnosis and management

Pulmonary nodules are often discovered incidentally during CT scans performed for other reasons. While the vast majority of nodules are benign, a small percentage may represent early-stage lung cancer with the potential for curative treatments. With the growing use of CT for both clinical purposes and lung cancer screening, the number of pulmonary nodules detected is expected to increase substantially. Despite well-established guidelines, many nodules do not receive proper evaluation due to a variety of factors, including inadequate coordination of care and financial and social barriers. To address this quality gap, novel approaches such as multidisciplinary nodule clinics and multidisciplinary boards may be necessary. As pulmonary nodules may indicate early-stage lung cancer, it is crucial to adopt a risk-stratified approach to identify potential lung cancers at an early stage, while minimizing the risk of harm and expense associated with over investigation of low-risk nodules. This article, authored by multiple specialists involved in nodule management, delves into the diagnostic approach to lung nodules. It covers the process of determining whether a patient requires tissue sampling or continued surveillance. Additionally, the article provides an in-depth examination of the various biopsy and therapeutic options available for malignant lung nodules. The article also emphasizes the significance of early detection in reducing lung cancer mortality, especially among high-risk populations. Furthermore, it addresses the creation of a comprehensive lung nodule program, which involves smoking cessation, lung cancer screening, and systematic evaluation and follow-up of both incidental and screen-detected nodules.

Tips and Tricks in Thoracic Radiology for Beginners: A Findings-Based Approach

This review has the purpose of illustrating schematically and comprehensively the key concepts for the beginner who approaches chest radiology for the first time. The approach to thoracic imaging may be challenging for the beginner due to the wide spectrum of diseases, their overlap, and the complexity of radiological findings. The first step consists of the proper assessment of the basic imaging findings. This review is divided into three main districts (mediastinum, pleura, focal and diffuse diseases of the lung parenchyma): the main findings will be discussed in a clinical scenario. Radiological tips and tricks, and relative clinical background, will be provided to orient the beginner toward the differential diagnoses of the main thoracic diseases.

Effectiveness of one-shot dual-energy subtraction chest radiography with flat-panel detector in distinguishing between calcified and non-calcified nodules

The purpose of this study was to evaluate the added value of the soft tissue image obtained by the one-shot dual-energy subtraction (DES) method using a flat-panel detector compared with the standard image alone in distinguishing calcified from non-calcified nodules on chest radiographs. We evaluated 155 nodules (48 calcified and 107 non-calcified) in 139 patients. Five radiologists (readers 1 - 5) with 26, 14, 8, 6 and 3 years of experience, respectively, evaluated whether the nodules were calcified using chest radiography. CT was used as the gold standard of calcification and non-calcification. Accuracy and area under the receiver operating characteristic curve (AUC) were compared between analyses with and without soft tissue images. The misdiagnosis ratio (false positive plus false negative ratios) when nodules and bones overlapped was also examined. The accuracy of all radiologists increased after adding soft tissue images (readers 1 - 5: 89.7% vs. 92.3% [P = 0.206], 83.2% vs. 87.7% [P = 0.178], 79.4% vs. 92.3% [P < 0.001], 77.4% vs. 87.1% [P = 0.007], and 63.2% vs. 83.2% [P < 0.001], respectively). AUCs for all the readers improved, except for reader 2 (readers 1 - 5: 0.927 vs. 0.937 [P = 0.495], 0.853 vs. 0.834 [P = 0.624], 0.825 vs. 0.878 [P = 0.151], 0.808 vs. 0.896 [P < 0.001], and 0.694 vs. 0.846 [P < 0.001], respectively). The misdiagnosis ratio for nodules that overlapped with the bone decreased after adding soft tissue images in all readers (11.5% vs. 7.6% [P = 0.096], 17.6% vs. 12.2% [P = 0.144], 21.4% vs. 7.6% [P < 0.001], 22.1% vs. 14.5% [P = 0.050] and 35.9% vs. 16.0% [P < 0.001], respectively), particularly that of readers 3 - 5. In conclusion, the soft tissue images obtained using one-shot DES with a flat-panel detector have added value in distinguishing calcified from non-calcified nodules on chest radiographs, especially for less experienced radiologists.

A case of congenital multiple epiphyseal dysplasia from the Late Migration Period graveyard in Drnholec (Czech Republic)

OBJECTIVE

To contribute to differential diagnosis of multiple epiphyseal dysplasia (MED) in archeological and clinical contexts.

MATERIALS

A skeleton of a 30- to 45-year-old male (grave no. 806) from the Late Migration Period graveyard in Drnholec-Pod sýpkou (Czech Republic), radio-carbon dated to AD 492-530.

METHODS

Morphological and metric analyses.

RESULTS

Significant pathological changes were noted on ossa coxae and proximal ends of the femora, which appear similar to changes associated with Legg-Calvé-Perthes disease. X-ray examination made it possible to rule out pseudoachondroplasia, rickets and metabolic bone diseases.

CONCLUSIONS

The finding was evaluated as a probable case of congenital multiple epiphyseal dysplasia.

SIGNIFICANCE

This case will contribute to the construction of estimates of the occurrence of this disease in historical populations and can be instructive for diagnostics in current medical practice.

LIMITATIONS

The final diagnosis is limited by the lack of genetic analysis.

SUGGESTION FOR THE FUTURE RESEARCH

Further clarification leading to diagnosis will benefit from genetic analysis and evaluation of skeletal remains throughout Europe.

Diffuse pulmonary ossification: A case report unveiling clinical and histopathological challenges

Diffuse pulmonary ossification (DPO) is a rare pulmonary condition characterized by the diffuse formation of mature bone in the lungs. Pulmonary ossification, in general, can be subdivided into diffuse pulmonary ossification (DPO) and nodular pulmonary ossification (NPO). DPO occurs most commonly in the settings of chronic pulmonary conditions; however, idiopathic cases have been reported. We present a case of DPO in a 36-year-old man with progressive exertional dyspnea, productive cough, and occasional hemoptysis. Imaging studies showed innumerable pulmonary nodules scattered throughout both lungs. Initially, the diagnoses of pulmonary alveolar microlithiasis (PAM) or, less likely miliary tuberculosis (TB) were considered. However, Quantiferon TB test was negative and genetic testing was negative for SLC34A2, lowering the probability of PAM. The patient underwent a segmentectomy. Microscopic examination showed ramifying spicules of mature woven bone and fatty marrow consistent with DPO. There were no significant underlying pathologic findings, such as interstitial fibrosis, granulomas, organizing pneumonia, or significant inflammation in the background lung parenchyma. In conclusion, clinicians and radiologists need to be aware of DPO in the differential diagnosis of miliary tuberculosis and pulmonary alveolar microlithiasis. The absence of an underlying chronic pulmonary condition does not exclude the possibility of DPO.

Pathogenesis of Pulmonary Calcification and Homologies with Biomineralization in Other Tissues

Lungs often present tissue calcifications and even ossifications, both in the context of high or normal serum calcium levels. Precise mechanisms governing lung calcifications have not been explored. Herein, we emphasize recent advances about calcification processes in other tissues (especially vascular and bone calcifications) and discuss potential sources of calcium precipitates in the lungs, involvement of mineralization promoters and crystallization inhibitors, as well as specific cytokine milieu and cellular phenotypes characteristic for lung diseases, which may be involved in pulmonary calcifications. Further studies are necessary to demonstrate the exact mechanisms underlying calcifications in the lungs, document homologies in biomineralization processes between various tissues in physiological and pathologic conditions, and unravel any locally specific characteristics of mineralization processes that may be targeted to reduce or prevent functionally relevant lung calcifications without negatively affecting the skeleton.

Nothing but lung and bones: Longitudinal evolution and quantitative analysis in a case of idiopathic diffuse pulmonary ossification

A 77-year-old Caucasian man, a former surveyor in a chemical company, underwent a chest X-ray (CXR) as a follow-up exam for a melanoma of the back, surgically removed.

CXR showed interstitial thickening in both lower lobes; then, a high-resolution computed tomography of the chest (HRCT) was performed to further investigate these findings, revealing multiple small, calcified nodules with branching appearance at both lung bases.

Clinical examination and exposure history were negative, except for a decrease in diffusing capacity for carbon monoxide resulting from pulmonary function tests.

Surgical lung biopsy was performed; histology revealed numerous nodules and branching tubules of bone tissue, some of which with marrow elements.

After multidisciplinary discussion of the case, a diagnosis of idiopathic diffuse pulmonary ossification (DPO) was considered.

Clinical status of the patient was stable over time, despite the increase in extent of calcifications.

DPO is an uncommon condition that should be considered in different clinical-radiological settings; multidisciplinary discussion is essential for the final diagnosis.

Atypical pulmonary metastases in children: the spectrum of radiologic findings

Pulmonary nodules present a diagnostic challenge when they appear as atypical metastases in pediatric oncology patients. Chest computed tomography (CT) is the primary imaging modality for assessing lung nodules. In pediatric populations, Wilms tumor and osteosarcoma are the cancers most likely to produce pulmonary metastasis, both typical and atypical. This pictorial essay provides a thorough description of the specific radiologic features of atypical pediatric pulmonary metastases, and their pathogenesis and differential diagnosis. We also address diagnostic approaches to incidental lung nodules in healthy children found in the literature. Our aim is to help radiologists identify atypical lung metastases on CT, ensuring that children receive prompt, and potentially lifesaving, treatment.

Detectability of pulmonary ossifications in fibrotic lung on ultra-high-resolution CT using 2048 matrix size and 0.25-mm slice thickness

To investigate the prevalence of nodular pulmonary ossifications (POs) in patients with honeycombing on ultra-high-resolution CT (UHRCT) and to compare the detectability of nodular POs between images reconstructed using the ultra-high-resolution setting (UHR-setting) and those using the conventional setting (C-setting) on UHRCT. Twenty patients with honeycombing in the lung were evaluated retrospectively. All patients underwent non-contrast-enhanced UHRCT. Images were reconstructed with UHR-setting (matrix, 2048 × 2048; slice thickness, 0.25 mm) and with C-setting (matrix size, 512 × 512; slice thickness, 0.5 mm). Two chest radiologists independently recorded the number of nodular POs (< 4 mm diameter) in each lung lobes. Each lobe was classified as one of the following five categories according to the number of POs: C0, none; C1, 1-4 POs; C2, 5-9 POs; C3, 10-49 POs; and C4, ≥ 50 POs. The maximum CT values of the POs were measured and compared between the two settings. PO categories were significantly higher with UHR-setting than with C-setting (p < 0.001). Maximum CT values were significantly higher with UHR-setting than with C-setting (p < 0.001). Nodular POs were seen in 80% or more of patients with honeycombing and more easily detected in images reconstructed with UHR-setting than in those with C-setting.

The CRISPR/Cas9 Minipig-A Transgenic Minipig to Produce Specific Mutations in Designated Tissues

The generation of large transgenic animals is impeded by complex cloning, long maturation and gastrulation times. An introduction of multiple gene alterations increases the complexity. We have cloned a transgenic Cas9 minipig to introduce multiple mutations by CRISPR in somatic cells. Transgenic Cas9 pigs were generated by somatic cell nuclear transfer and were backcrossed to Göttingen Minipigs for two generations. Cas9 expression was controlled by FlpO-mediated recombination and was visualized by translation from red to yellow fluorescent protein. In vitro analyses in primary fibroblasts, keratinocytes and lung epithelial cells confirmed the genetic alterations executed by the viral delivery of single guide RNAs (sgRNA) to the target cells. Moreover, multiple gene alterations could be introduced simultaneously in a cell by viral delivery of sgRNAs. Cells with loss of TP53, PTEN and gain-of-function mutation in KRAS^G12D showed increased proliferation, confirming a transformation of the primary cells. An in vivo activation of Cas9 expression could be induced by viral delivery to the skin. Overall, we have generated a minipig with conditional expression of Cas9, where multiple gene alterations can be introduced to somatic cells by viral delivery of sgRNA. The development of a transgenic Cas9 minipig facilitates the creation of complex pre-clinical models for cancer research.

Natural Language Processing to Identify Pulmonary Nodules and Extract Nodule Characteristics From Radiology Reports

BACKGROUND

There is an urgent need for population-based studies on managing patients with pulmonary nodules.

RESEARCH QUESTION

Is it possible to identify pulmonary nodules and associated characteristics using an automated method?

STUDY DESIGN AND METHODS

We revised and refined an existing natural language processing (NLP) algorithm to identify radiology transcripts with pulmonary nodules and greatly expanded its functionality to identify the characteristics of the largest nodule, when present, including size, lobe, laterality, attenuation, calcification, and edge. We compared NLP results with a reference standard of manual transcript review in a random test sample of 200 radiology transcripts. We applied the final automated method to a larger cohort of patients who underwent chest CT scan in an integrated health care system from 2006 to 2016, and described their demographic and clinical characteristics.

RESULTS

In the test sample, the NLP algorithm had very high sensitivity (98.6%; 95% CI, 95.0%-99.8%) and specificity (100%; 95% CI, 93.9%-100%) for identifying pulmonary nodules. For attenuation, edge, and calcification, the NLP algorithm achieved similar accuracies, and it correctly identified the diameter of the largest nodule in 135 of 141 cases (95.7%; 95% CI, 91.0%-98.4%). In the larger cohort, the NLP found 217,771 reports with nodules among 717,304 chest CT reports (30.4%). From 2006 to 2016, the number of reports with nodules increased by 150%, and the mean size of the largest nodule gradually decreased from 11 to 8.9 mm. Radiologists documented the laterality and lobe (90%-95%) more often than the attenuation, calcification, and edge characteristics (11%-14%).

INTERPRETATION

The NLP algorithm identified pulmonary nodules and associated characteristics with high accuracy. In our community practice settings, the documentation of nodule characteristics is incomplete. Our results call for better documentation of nodule findings. The NLP algorithm can be used in population-based studies to identify pulmonary nodules, avoiding labor-intensive chart review.

[Diagnosis and treatment of benign lung tumors]

Benign lung tumors account 2-12% of all lung neoplasms. The classification of lung tumors, adopted by the World Health Organization in 2015, is reported with a detailed indication of all changes based on immunohistochemical and genetic studies. Diagnosis with computed tomography, dynamic and perfusion computed tomography, virtual bronchoscopy and positron emission tomography is described. These methods ensure 94-98% sensitivity for differentiation with malignancies. CT and ultrasound signs of benign tumors are presented. Surgical strategy for newly diagnosed nodes in the lungs is analyzed depending on their dimensions and risk factors. It was shown that comprehensive examination with possible surgical verification of the diagnosis is necessary for nodes over 6 mm and moderate-to-high risk factors. The authors describe argon plasma and laser destruction, bronchoplastic procedures for central benign tumors, thoracoscopy for peripheral neoplasms. One can conclude that high-tech methods of radiological and nuclear diagnosis are valuable to determine benign neoplasms and their dimensions with a high degree of reliability. Endoscopic and thoracoscopic procedures are successfully used for benign tumors.

Bilateral Diffuse Nodular Pulmonary Ossification Mimicking Metastatic Disease in a Patient with Fibrolamellar Hepatocellular Carcinoma

Pulmonary ossification (PO) is a rare finding, characterized by mature bone formation in the lung parenchyma. We report a 20-year-old female patient diagnosed with fibrolamellar hepatocellular carcinoma (FL-HCC) and bilateral diffuse nodular PO. The patient presented with a unifocal left liver mass and multiple bilateral pulmonary lesions, which were treated as metastatic disease. The patient received neoadjuvant chemotherapy, followed by left hepatectomy, and bilateral staged thoracotomies for clearance of the pulmonary disease. The histology of the pulmonary nodules demonstrated nodular type PO. We present the history, the course of treatment, imaging, and histologic findings of this rare disease process that could mimic metastatic pulmonary disease.

Pulmonary Hyalinizing Granuloma: A Rare Cause of a Benign Lung Mass

Pulmonary hyalinizing granuloma (PHG) is a rare, benign lung disease of unknown etiology. It usually manifests as solitary and sometimes as multiple pulmonary nodules. It may have irregular margins, cavitation, or calcifications mimicking metastasis or primary lung neoplasm. It should be considered in the differential diagnosis of pulmonary nodules or masses. In this report, we present an unusual case of incidental slow-growing lung mass in a patient with 30 pack-year smoking history, construction-based occupation. The pleural-based calcified nodule in the left upper lobe gradually increased in size over ten years without any hilar or mediastinal lymphadenopathy. For an accurate diagnosis, PET-scan and histopathological analysis through wedge resection by video-assisted thoracoscopic surgery (VATS) were done. The biopsy findings were consistent with pulmonary hyalinizing granuloma, a rare benign cause of lung mass with an excellent long-term prognosis.

COVID-19 or non-COVID viral pneumonia: How to differentiate based on the radiologic findings?

Influenza viruses were responsible for most adult viral pneumonia. Presently, coronavirus disease 2019 (COVID-19) has evolved into serious global pandemic. COVID-19 outbreak is expected to persist in months to come that will be synchronous with the influenza season. The management, prognosis, and protection for these two viral pneumonias differ considerably and differentiating between them has a high impact on the patient outcome. Reverse transcriptase polymerase chain reaction is highly specific but has suboptimal sensitivity. Chest computed tomography (CT) has a high sensitivity for detection of pulmonary disease manifestations and can play a key-role in diagnosing COVID-19. We reviewed 47 studies and delineated CT findings of COVID-19 and influenza pneumonia. The differences observed in the chest CT scan can be helpful in differentiation. For instance, ground glass opacities (GGOs), as the most frequent imaging finding in both diseases, can differ in the pattern of distribution. Peripheral and posterior distribution, multilobular distribution, pure or clear margin GGOs were more commonly reported in COVID-19, whereas central or peri-bronchovascular GGOs and pure consolidations were more seen in influenza A (H1N1). In review of other imaging findings, further differences were noticed. Subpleural curvilinear lines, sugar melted sign, intra-lesional vascular enlargement, reverse halo sign, and fibrotic bands were more reported in COVID-19 than H1N1, while air space nodule, tree-in-bud, bronchiectasia, pleural effusion, and cavitation were more seen in H1N1. This delineation, when combined with clinical manifestations and laboratory results may help to differentiate these two viral infections.

Neoplastic pathology at the crossroads between neck imaging and cardiothoracic imaging

The thoracic inlet is located at the crossroads between imaging of the neck and the chest. Its location is an important anatomic landmark, serving as the central conducting pathway for many vital structures extending from the neck into the chest and vice versa. Many critical body systems, including the respiratory, lymphatic, neurologic, enteric, musculoskeletal, endocrine, and vascular systems, are located within this region. Neoplasms, both benign and malignant, can arise in any of the body systems located in this area. Due to the small size of this anatomic location, pathology is easily overlooked and imagers should be aware of the imaging appearance of these neoplasms, as well as which imaging modality is the most appropriate for neoplasm evaluation. This article will present an image rich, system-based discussion of the neoplastic pathology that can occur in this region. The anatomy of the thoracic inlet and the non-neoplastic pathology of the thoracic inlet have been covered in our companion article.

Mediastinal Cartilaginous Hamartoma

Pulmonary hamartomas are usually solitary, nodular benign lesions in the parenchyma of the lung. They are rarely situated in endobronchial areas, and very few cases are reported with the mediastinum. 

A 56-year-old female patient got a CT-scan conducted due to coughing and breathlessness and was diagnosed with a nodular lesion in the medial mediastinum. The lesion was operated: it measured up to 4 cm in the largest diameter, had a smooth surface, was of rather soft but elastic consistency, and was extirpated. At pathology, on cut section, it was yellowish and lobular, and with a mixture of cartilaginous, fibrous and adipose tissues with some smooth muscle cell fibers and myxoid areas.

The diagnosis of pulmonary hamartoma was made with atypical medial mediastinal localization. This rare presentation could pose some differential diagnostic problems in the clinical diagnosis of more frequent primary and metastatic malignant diseases.

Missed Lung Cancers on Chest Radiograph: An Illustrative Review of Common Blind Spots on Chest Radiograph with Emphasis on Various Radiologic Presentations of Lung Cancers

Missed lung cancers on chest radiograph (CXR) may delay the diagnosis and affect the prognosis. CXR is the primary imaging modality to evaluate the lungs and mediastinum in daily practice. The purpose of this article is to review chest radiographs for common blind spots and highlight the importance of various radiologic presentations in primary lung cancer to avoid significant diagnostic errors on CXR.

Chest imaging using signs, symbols, and naturalistic images: a practical guide for radiologists and non-radiologists

Several imaging findings of thoracic diseases have been referred-on chest radiographs or CT scans-to signs, symbols, or naturalistic images. Most of these imaging findings include the air bronchogram sign, the air crescent sign, the arcade-like sign, the atoll sign, the cheerios sign, the crazy paving appearance, the comet-tail sign, the darkus bronchus sign, the doughnut sign, the pattern of eggshell calcifications, the feeding vessel sign, the finger-in-gloove sign, the galaxy sign, the ginkgo leaf sign, the Golden-S sign, the halo sign, the headcheese sign, the honeycombing appearance, the interface sign, the knuckle sign, the monod sign, the mosaic attenuation, the Oreo-cookie sign, the polo-mint sign, the presence of popcorn calcifications, the positive bronchus sign, the railway track appearance, the scimitar sign, the signet ring sign, the snowstorm sign, the sunburst sign, the tree-in-bud distribution, and the tram truck line appearance. These associations are very helpful for radiologists and non-radiologists and increase learning and assimilation of concepts.Therefore, the aim of this pictorial review is to highlight the main thoracic imaging findings that may be associated with signs, symbols, or naturalistic images: an "iconographic" glossary of terms used for thoracic imaging is reproduced-placing side by side radiological features and naturalistic figures, symbols, and schematic drawings.

Evaluation of the solitary pulmonary nodule

The solitary pulmonary nodule represents a common diagnostic challenge for clinicians. While most are benign, a significant number represent early, potentially curable lung cancers. With the increased utilisation of chest computed tomography, solitary pulmonary nodules are increasingly being identified and with lung cancer screening programmes now on the horizon globally, it is crucial clinicians are familiar with the evaluation and management of solitary pulmonary nodules. Through the evaluation of patient risk factors combined with computed tomography characteristics of solitary pulmonary nodules, including size, growth rate, margin characteristics, calcification, density and location; a clinician can assess the risk of malignancy. This article provides an up to date review of the imaging features of both benign and malignant solitary pulmonary nodules to assist in the identification of nodules that require histological confirmation or ongoing surveillance. In addition, we summarise the newly updated Fleischner Society Guidelines that provide clinicians with a framework for the evaluation and management of solitary pulmonary nodules.

Primary pulmonary synovial sarcoma with calcification: A case report

The lung is the organ most commonly affected by primary synovial sarcoma. Intratumoral calcification is less common in this organ versus soft tissue. Meanwhile, the presence of calcification in a lung nodule reduces the risk of lung cancer. Here, we report a case of pulmonary synovial sarcoma which manifested as a nodule with calcification, depicted on computed tomography (CT). A 52-year-old asymptomatic male was referred to Saitama Medical University International Medical Center and CT revealed a well-defined nodule (1.8 cm), with punctate and eccentric calcification in the right lower lobe. Enhanced CT and 18F-fluorodeoxyglucose positron-emission tomography suggested a malignant tumor, and surgery was performed. Histology provided a preliminary diagnosis of monophasic spindle-cell synovial sarcoma with hyalinized collagen bands and calcifications. Genetically, the presence of the SYT-SSX2 fusion gene was consistent with the features of this disease. We conclude that primary pulmonary synovial sarcoma should be listed as a differential diagnosis for solitary pulmonary nodules with calcification.

A case of gastrointestinal histoplasmosis with esophageal involvement

Histoplasmosis is a common infection endemic to the Ohio and Mississippi River Valleys caused by the inhalation of Histoplasma capsulatum spores from contaminated soil. Most infections are asymptomatic; however, patients with impaired cellular immunity (HIV infection, hematologic malignancy, solid organ transplant, hematopoietic stem cell transplant or TNF-⍺ inhibitor use) are at risk for disseminated disease. Disseminated histoplasmosis commonly affects the lungs, liver, spleen, bone marrow and gastrointestinal tract. Esophageal involvement is rare and usually due to extrinsic compression from affected mediastinal/hilar lymph nodes. Herein, we report a case of disseminated histoplasmosis in an AIDs patient involving the esophagus, without evidence of mediastinal involvement.

Radiological Signs of Latent Tuberculosis on Chest Radiography: A Systematic Review and Meta-Analysis

Objective

Current guidelines recommend screening for latent tuberculosis infection (LTBI) with a tuberculin skin test (TST) or interferon gamma release assay (IGRA), or both. Many also recommend chest radiography (CXR), although its added value is uncertain. This systematic review assessed the prevalence of abnormalities suggestive of LTBI on CXR (LTBI-CXR lesions) and evaluated the strength of the association.

Method

We searched 4 databases up to September 2017 and systematically reviewed cross-sectional and cohort studies reporting LTBI-CXR lesions in individuals with a positive TST or IGRA, or both, result. Prevalence estimates were pooled using random effects models and odds ratios (ORs) were used to calculate risk estimates.

Results

In the 26 included studies, the pooled proportion of individuals with LTBI having LTBI-CXR lesions was 0.15 (95% confidence interval [CI], 0.12–0.18]. In 16 studies that reported on individuals with LTBI and uninfected controls, LTBI-CXR lesions were associated with a positive TST result ≥ 5 mm or ≥ 10 mm (OR, 2.45; 95% CI, 1.00–5.99; and OR, 2.06; 95% CI, 1.38–3.09, respectively) and with a positive QuantiFERON result (OR, 1.99; 95% CI, 1.17–3.39) compared to CXR in uninfected controls. Although few studies reported specified lesions, calcified nodules were most frequently reported in individuals with LTBI (proportion, 0.07; 95% CI, 0.02–0.11).

Conclusions

Lesions on CXR suggestive of previous infection with Mycobacterium tuberculosis were significantly associated with positive tests for LTBI, although the sensitivity was only 15%. This finding may have added value when detection of past LTBI is important but immunodiagnostic tests may be unreliable.

Thoracic calcifications on magnetic resonance imaging: correlations with computed tomography

OBJECTIVE

To identify the characteristics of thoracic calcifications on magnetic resonance (MR) imaging, as well as correlations between MR imaging and CT findings.

METHODS

This was a retrospective study including data on 62 patients undergoing CT scans and MR imaging of the chest at any of seven hospitals in the Brazilian states of Rio Grande do Sul, São Paulo, and Rio de Janeiro between March of 2014 and June of 2016 and presenting with calcifications on CT scans. T1- and T2-weighted MR images (T1- and T2-WIs) were semiquantitatively analyzed, and the lesion-to-muscle signal intensity ratio (LMSIR) was estimated. Differences between neoplastic and non-neoplastic lesions were analyzed.

RESULTS

Eighty-four calcified lesions were analyzed. Mean lesion density on CT was 367 ± 435 HU. Median LMSIRs on T1- and T2-WIs were 0.4 (interquartile range [IQR], 0.1-0.7) and 0.2 (IQR, 0.0-0.7), respectively. Most of the lesions were hypointense on T1- and T2-WIs (n = 52 [61.9%] and n = 39 [46.4%], respectively). In addition, 19 (22.6%) were undetectable on T1-WIs (LMSIR = 0) and 36 (42.9%) were undetectable on T2-WIs (LMSIR = 0). Finally, 15.5% were hyperintense on T1-WIs and 9.5% were hyperintense on T2-WIs. Median LMSIR was significantly higher for neoplastic lesions than for non-neoplastic lesions. There was a very weak and statistically insignificant negative correlation between lesion density on CT and the following variables: signal intensity on T1-WIs, LMSIR on T1-WIs, and signal intensity on T2-WIs (r = -0.13, p = 0.24; r = -0.18, p = 0.10; and r = -0.16, p = 0.16, respectively). Lesion density on CT was weakly but significantly correlated with LMSIR on T2-WIs (r = -0.29, p < 0.05).

CONCLUSIONS

Thoracic calcifications have variable signal intensity on T1- and T2-weighted MR images, sometimes appearing hyperintense. Lesion density on CT appears to correlate negatively with lesion signal intensity on MR images.

A Novel Computer-Aided Diagnosis Scheme on Small Annotated Set: G2C-CAD

Purpose

Computer-aided diagnosis (CAD) can aid in improving diagnostic level; however, the main problem currently faced by CAD is that it cannot obtain sufficient labeled samples. To solve this problem, in this study, we adopt a generative adversarial network (GAN) approach and design a semisupervised learning algorithm, named G2C-CAD.

Methods

From the National Cancer Institute (NCI) Lung Image Database Consortium (LIDC) dataset, we extracted four types of pulmonary nodule sign images closely related to lung cancer: noncentral calcification, lobulation, spiculation, and nonsolid/ground-glass opacity (GGO) texture, obtaining a total of 3,196 samples. In addition, we randomly selected 2,000 non-lesion image blocks as negative samples. We split the data 90% for training and 10% for testing. We designed a DCGAN generative adversarial framework and trained it on the small sample set. We also trained our designed CNN-based fuzzy Co-forest on the labeled small sample set and obtained a preliminary classifier. Then, coupled with the simulated unlabeled samples generated by the trained DCGAN, we conducted iterative semisupervised learning, which continually improved the classification performance of the fuzzy Co-forest until the termination condition was reached. Finally, we tested the fuzzy Co-forest and compared its performance with that of a C4.5 random decision forest and the G2C-CAD system without the fuzzy scheme, using ROC and confusion matrix for evaluation.

Results

Four different types of lung cancer-related signs were used in the classification experiment: noncentral calcification, lobulation, spiculation, and nonsolid/ground-glass opacity (GGO) texture, along with negative image samples. For these five classes, the G2C-CAD system obtained AUCs of 0.946, 0.912, 0.908, 0.887, and 0.939, respectively. The average accuracy of G2C-CAD exceeded that of the C4.5 random decision tree by 14%. G2C-CAD also obtained promising test results on the LISS signs dataset; its AUCs for GGO, lobulation, spiculation, pleural indentation, and negative image samples were 0.972, 0.964, 0.941, 0.967, and 0.953, respectively.

Conclusion

The experimental results show that G2C-CAD is an appropriate method for addressing the problem of insufficient labeled samples in the medical image analysis field. Moreover, our system can be used to establish a training sample library for CAD classification diagnosis, which is important for future medical image analysis.

Macrophage Origin, Metabolic Reprogramming and IL-1 Signaling: Promises and Pitfalls in Lung Cancer

Macrophages are tissue-resident cells that act as immune sentinels to maintain tissue integrity, preserve self-tolerance and protect against invading pathogens. Lung macrophages within the distal airways face around 8000⁻9000 L of air every day and for that reason are continuously exposed to a variety of inhaled particles, allergens or airborne microbes. Chronic exposure to irritant particles can prime macrophages to mediate a smoldering inflammatory response creating a mutagenic environment and favoring cancer initiation. Tumor-associated macrophages (TAMs) represent the majority of the tumor stroma and maintain intricate interactions with malignant cells within the tumor microenvironment (TME) largely influencing the outcome of cancer growth and metastasis. A number of macrophage-centered approaches have been investigated as potential cancer therapy and include strategies to limit their infiltration or exploit their antitumor effector functions. Recently, strategies aimed at targeting IL-1 signaling pathway using a blocking antibody have unexpectedly shown great promise on incident lung cancer. Here, we review the current understanding of the bridge between TAM metabolism, IL-1 signaling, and effector functions in lung adenocarcinoma and address the challenges to successfully incorporating these pathways into current anticancer regimens.

Abnormalities suggestive of latent tuberculosis infection on chest radiography; how specific are they?

Background

Several radiological features have been reported in association with latent tuberculosis infection (LTBI) but it has not been studied which are specific. The aim of this study was to evaluate allegedly characteristic abnormalities on chest radiography (CXR) in patients with LTBI compared to uninfected controls.

Methods

From 236 patients tested with QuantiFERON-TB Gold In-Tube (QFT), the CXR was re-evaluated in a blinded fashion for fibrotic scarring, (non-)calcified nodules and pleural thickening. LTBI was defined as presence of a positive QFT result and/or positive tuberculin skin test result stratified by Bacille Calmette-Guérin-vaccination status.

Results

Any predefined abnormality of LTBI was observed in 116/236 (49.2%) patients, the frequency not being different between groups. However, the specificity for LTBI of a fibrotic scar ≥ 2 cm² was 100% [95% CI: 92.0%–100%] and of a calcified nodule ≥1.5 mm was 95.7% [95% CI: 85.2%–99.5%]. The frequency of non-calcified nodules and pleural thickening did not differ between groups.

Conclusion

Only a fibrotic scar ≥ 2 cm² and/or a calcified nodule ≥1.5 mm were significantly associated with LTBI. This finding is clinically relevant mainly in patients who are at significant risk of TB reactivation and in whom indirect diagnostic tests may be unreliable.

Visual assessment of calcification in solitary pulmonary nodules on chest radiography: correlation with volumetric quantification of calcification

PURPOSE

To assess the ability of digital chest radiography (CXR) to reveal calcification in solitary pulmonary nodules (SPNs), and to examine the correlation between a visual assessment and volumetric quantification of the calcification.

MATERIALS AND METHODS

This study was a retrospective review of 220 SPNs identified by both CXR and chest CT. Eleven observers did blind review of the CXR images and scored nodule calcification on a confidence scale of 1 to 5. The area under the receiver operating characteristics (ROC) curve (AUC) was obtained to analyze the diagnostic performance. The intraclass correlation coefficient (ICC) for interrater reliability was calculated. The AUC and ICC were calculated according to the following nodule diameter groups: group 1 (< 10 mm), group 2 (≥ 10 mm and < 20 mm), and group 3 (≥ 20 mm).

RESULTS

Of the 220 SPNs, 145 SPNs (65.6%) were identified as non-calcified and 75 (34.4%) as calcified. The average percentage of calcification volume in SPN > 160 HU (Vol160HU) among the 75 calcified nodules was 47.5%. The mean Vol160HU of the 68 SPNs classified as having definite calcification was 51.1%. The overall AUC was 0.71. The AUCs for groups 1, 2, and 3 was 0.835, 0.639, and 0.620, respectively. The ICCs for groups 1, 2, 3 was 0.65, 0.48, and 0.33, respectively.

CONCLUSION

The overall diagnostic performance of digital CXR to predict calcification in SPNs was moderately accurate and the diagnostic performance for predicting calcification in SPNs was significantly higher, and interobserver reproducibility was good when SPN < 10 mm compared with ≥ 10 mm in diameter.

KEY POINTS

• The misdiagnosis of a non-calcified nodule as a calcified one by CXR could lead to poor management choices for the SPN. • The diagnostic performance of CXR in predicting calcification was best for nodules < 10 mm in diameter. SPNs with calcification of approximately 50% of their volume tend to be considered calcified. • The diagnostic performance of CXR in identifying calcification was low for nodules ≥ 10 mm in diameter; therefore, we should carefully evaluate calcification carefully for nodules ≥ 10 mm.

Computed Tomography Imaging Findings of Pulmonary Chondroma

PURPOSE

To characterize the computed tomography (CT) imaging findings in patients with pulmonary chondroma.

METHODS

We examined CT imaging findings of eight patients with histopathologically verified pulmonary chondroma. We assessed the location, size, shape, margins, amount of calcification, calcification pattern, and attenuation on precontrast and enhancement CT.

RESULTS

All patients exhibited solitary, mildly lobulated pulmonary masses, which were located in the right lung in four cases and the left lung in four cases. The mean lesion size was 3.7 cm (range 0.9-10.7 cm). All eight tumours had a well-defined margin. On plain CT images, seven of the cases (87.5%) showed a mass with varying degrees of calcification, which included strip-like punctate (n=5) and ring (n=2) patterns. One patient with a large lesion (10.7 cm) showed chest wall adhesion. On contrast-enhanced CT images, all lesions demonstrated slight inhomogeneous enhancement ≤14 HU.

CONCLUSION

CT is the reference standard diagnostic technique for locating pulmonary chondroma. In most cases, CT findings show some characteristics that are important in the diagnosis, surgical planning, and follow-up of the tumour.

Factors affecting bacterial culture positivity in specimens from bronchoscopy in patients with suspected lung cancer

BACKGROUND

Bronchoscopy is important to diagnose lung cancer. However, some patients who undergo bronchoscopic procedures develop respiratory tract infections. Little is known about the proportion of pathogen-positive results in bacterial cultures from diagnostic bronchoscopy samples in patients with suspected lung cancer. This study aimed to determine the rate of positive bacterial cultures after diagnostic bronchoscopy in patients with suspected lung cancer and the relationship among culture results, clinical characteristics, and respiratory tract infections.

METHODS

We retrospectively reviewed the medical records of all immunocompetent patients who underwent bronchoscopy and had culture and histological samples for the diagnosis of peripheral pulmonary lesions from September 2012 to August 2014 at the National Cancer Center in Tokyo. We analyzed data and classified radiological lesions into the following categories: calcifications, cavitations, low-density areas, margin irregularities, and satellite nodules.

RESULTS

The study population consisted of 328 patients (median age, 69 years). We found that 65.9% of patients had malignant lesions and 4.2% of patients had positive cultures for pathogenic bacteria. The number of calcifications (p = 0.002, 95% CI: 2.17-41.10) was significantly higher in patients with positive bacterial isolates, according to the multivariate analysis, and bacterial culture positivity was not associated with the development of respiratory complications after bronchoscopy. Of the three patients with respiratory complications, all presented with cavitations.

CONCLUSION

Because of the low prevalence of positive bacterial cultures in patients with suspected lung cancer, bacterial culture may be limited to specific patients, such as those with calcifications. Lesions with cavitation warrant close monitoring.

EGFR-TKI-sensitive mutations in lung carcinomas: are they related to clinical features and CT findings?

Background

Epidermal growth factor receptor (EGFR) mutation testing is restricted to several limitations. In this study, we examined the relationship between EGFR mutation status and clinicoradiological characteristics in a Chinese cohort of patients.

Materials and methods

The data of patients who were diagnosed with lung carcinoma and underwent both EGFR testing and chest computed tomography (CT) at our hospital between January 1, 2011, and November 31, 2015, were retrospectively analyzed. The age, sex, and smoking index of the patients, the size, margin, and density of the tumor, and the presence of specific signs visible on the CT images were assessed.

Results

The results showed a higher rate of EGFR-tyrosine kinase inhibitor (TKI)-sensitive group than nonsensitive group in female patients and patients with a low smoking index (P<0.001, both). In logistic regression analyses, tumor size (P<0.001), smooth margins (P=0.015), and angular margins (P<0.001) were independent negative predictors of EGFR-TKI-sensitive group. Pleural indentation (P<0.001) and air bronchogram (P=0.025) were independent positive predictors of EGFR-TKI-sensitive group. Patients with squamous cell carcinoma had fewer sensitive mutations than those with either adenocarcinoma (P<0.001) or adenosquamous carcinoma (P<0.001).

Conclusion

Clinical and CT characteristics differed significantly between EGFR-TKI-sensitive and nonsensitive groups. Our findings may be useful in deciding therapeutic strategies for patients in whom EGFR testing is not possible.

Effect of Hybrid Kernel and Iterative Reconstruction on Objective and Subjective Analysis of Lung Nodule Calcification in Low-Dose Chest CT

Objective

To evaluate the differences in subjective calcification detection rates and objective calcium volumes in lung nodules according to different reconstruction methods using hybrid kernel (FC13-H) and iterative reconstruction (IR).

Materials and Methods

Overall, 35 patients with small (< 4 mm) calcified pulmonary nodules on chest CT were included. Raw data were reconstructed using filtered back projection (FBP) or IR algorithm (AIDR-3D; Canon Medical Systems Corporation), with three types of reconstruction kernel: conventional lung kernel (FC55), FC13-H and conventional soft tissue kernel (FC13). The calcium volumes of pulmonary nodules were quantified using the modified Agatston scoring method. Two radiologists independently interpreted the role of each nodule calcification on the six types of reconstructed images (FC55/FBP, FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D).

Results

Seventy-eight calcified nodules detected on FC55/FBP images were regarded as reference standards. The calcium detection rates of FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D protocols were 80.7%, 15.4%, 6.4%, 52.6%, and 28.2%, respectively, and FC13-H/AIDR-3D showed the smallest calcium detection rate. The calcium volume varied significantly with reconstruction protocols and FC13/AIDR-3D showed the smallest calcium volume (0.04 ± 0.22 mm³), followed by FC13-H/AIDR-3D.

Conclusion

Hybrid kernel and IR influence subjective detection and objective measurement of calcium in lung nodules, particularly when both techniques (FC13-H/AIDR-3D) are combined.

Recurrent Pneumonia due to Fibrosing Mediastinitis in a Teenage Girl: A Case Report with Long-Term Follow-Up

A teenage girl was evaluated for recurrent right pneumonia. The evaluation revealed a calcified mediastinal mass that compressed the right intermediate and middle lobar bronchi, as well as the right pulmonary artery and veins. The clinical picture together with imaging studies and borderline positive serology testing suggested a diagnosis of fibrosing mediastinitis associated with histoplasmosis. This rare condition is characterized by the local proliferation of invasive fibrous tissue within the mediastinum due to a hyperimmune reaction to Histoplasma capsulatum. Antifungal and anti-inflammatory therapies are usually ineffective, and surgical intervention contains a high morbidity risk. Palliative surgery and stenting of the compressed airway have been suggested. In the past, the prognosis was thought to be poor, but recent studies demonstrate a more positive outcome. Our patient had been radiologically and functionally stable under follow-up for over thirteen years and has married and delivered two healthy children, both following an uneventful pregnancy.

Chickenpox: an ageless disease

A 97-year-old woman presented with 4-day history of vesicular rash, initially at the feet but then spread up to the thighs bilaterally, abdomen and trunk. The initial differentials included bullous pemphigus and cellulitis by the emergency department. She was then managed as bullous pemphigus by the acute medical team and started on high-dose steroids, with no other differentials considered. When her care was taken over by the general medical team, varicella zoster virus (VZV) infection was suspected. After confirmation by the dermatology team regarding the clinical diagnosis and the positive VZV DNA swabs, she was started on acyclovir.

Pulmonary nodule detection in oncological patients - Value of respiratory-triggered, periodically rotated overlapping parallel T2-weighted imaging evaluated with PET/CT-MR

PURPOSE

To prospectively evaluate the detection and conspicuity of pulmonary nodules in an oncological population, using a tri-modality PET/CT-MR protocol including a respiration-gated T2-PROPELLER sequence for possible integration into a simultaneous PET/MR protocol.

METHODS

149 patients referred for staging of malignancy were prospectively enrolled in this single-center study. Imaging was performed on a tri-modality PET/CT-MR setup and was comprised of PET/CT and 3T-MR imaging with 3D dual-echo GRE pulse sequence (Dixon) and an axial respiration-gated T2-weighted PROPELLER (T2-P) sequence. Images were assessed for presence, conspicuity, size and interpretation of the pulmonary parenchymal nodules. McNemar's test was used to evaluate paired differences in nodule detection rates between MR and CT from PET/CT. The correlation of pulmonary nodule size in CT and MR imaging was assessed using Pearson correlation coefficient.

RESULTS

299 pulmonary nodules were detected on PET/CT. The detectability was significantly higher on T2-P (60%, p<0.01) compared to T1-weighted Dixon-type sequences (16.1-37.8%). T2-P had a significantly higher detection rate among FDG-positive (92.4%) and among confirmed malignant nodules (75.9%) compared to T1-Dixon. Nodules <10mm were detected less often by MR sequences than by CT (p < 0.01). However, nodules >10mm were detected equally well with T2-P (92.2%) and CT (p >0.05). In a per-patient analysis, there was no significant change in the clinical interpretation of the nodules detected with T2-P and CT.

CONCLUSION

Despite the overall lower detection rate compared with CT, the free-breathing respiratory gating T2-w sequence showed higher detectability in all evaluated categories compared to breath-hold T1-weighted MR sequences. Specifically, the T2-P was found to be not statistically different from CT in FDG-positive nodules, in detection of nodules >10mm and concerning conspicuity of pulmonary nodules. Overall, the additional time investment into T2-P seems to be justified since clinical relevant assessment of pulmonary lung nodules can mostly be done by T2-P in a whole body PET/MR staging of oncologic patients.

Microcalcifications in stone-obstructed human submandibular gland are associated with apoptosis and cell proliferation

OBJECTIVE

Human submandibular gland (SMG) stones are associated with inflammation, fibrosis and microcalcifications in the surrounding tissues. However, there is little information about the accompanying cell injury-repair process, apoptosis, and cell proliferation. The purpose of this study was to investigate such an association and its clinical significance.

DESIGN OF STUDY

Mid-gland paraffin sections of human SMGs ("stone glands") and normal SMGs ("non-stone glands") were subjected to stains for general histology (hematoxylin and eosin), fibrosis (Masson's trichrome), and calcification (alizarin red) and to immunohistochemistry for proliferative activity (Ki-67), and apoptosis (Caspase-3). Tissues were assessed for areas of inflammation, calcium deposition, and fibrosis, and for cycling and apoptotic cells.

RESULTS

Acini were atrophic and proportionately fewer in lobules with fibrosis in stone glands. Additionally, stone glands had intraluminal calcifications (microliths) in scattered excretory and striated ducts and blood vessel walls. Areas of inflammation and fibrosis were small and uncommon, and calcifications were not seen in non-stone glands. Proliferating and apoptotic cells were common in the main duct of stone glands where ciliated and mucous cell hyperplasia and stratified squamous metaplasia had occurred, uncommon in the main duct of non-stone glands, and uncommon in all other parenchymal elements of both stone and non-stone glands.

CONCLUSION

Stone obstruction in the main excretory ducts of SMG resulted in progressive depletion of acini from proximal to distal lobules via calcification, inflammation, fibrosis, and parenchymal cell atrophy, apoptosis and proliferation. Interlobular duct microliths contributed to this depletion by further provoking intralobular inflammation, fibrosis, and acinar atrophy.