CT features of osteosarcoma lung metastasis: a retrospective study of 127 patients

Objective: Osteosarcoma lung metastases have a wide variety of CT presentations, representing a challenge for radiologists. Knowledge of atypical CT patterns of lung metastasis is important to differentiate it from benign lung disease and synchronous lung cancer, as well as to determine the extent of primary disease. The objective of this study was to analyze CT features of osteosarcoma lung metastasis before and during chemotherapy. Methods: Two radiologists independently reviewed chest CT images of 127 patients with histopathologically confirmed osteosarcoma treated between May 10, 2012 and November 13, 2020. The images were divided into two groups for analysis: images obtained before chemotherapy and images obtained during chemotherapy (initial CT examination). Results: Seventy-five patients were diagnosed with synchronous or metachronous lung metastases. The most common CT findings were nodules (in 95% of the patients), distributed bilaterally (in 86%), with no predominance regarding craniocaudal distribution (in 71%). Calcification was observed in 47%. Less common findings included intravascular lesions (in 16%), cavitation (in 7%), and the halo sign (in 5%). The primary tumor size was significantly greater (i.e., > 10 cm) in patients with lung metastasis. Conclusions: On CT scans, osteosarcoma lung metastases typically appear as bilateral solid nodules. However, they can have atypical presentations, with calcification being the most common. Knowledge of the typical and atypical CT features of osteosarcoma lung metastasis could play a key role in improving image interpretation in these cases.

Crohn's disease: review and standardization of nomenclature

Crohn's disease is an inflammatory bowel disease that can affect any segment of the gastrointestinal tract. It has a variable clinical course, with alternating periods of disease activity and remission. Because the incidence and prevalence of Crohn's disease have been increasing, evaluation by imaging methods has become more important. The most widely used methods are computed tomography enterography, magnetic resonance enterography (as an elective examination), and contrast-enhanced computed tomography (in the context of emergency). Computed tomography enterography and magnetic resonance enterography are useful for diagnosis, follow-up, evaluation of complications, and prognosis. Both can be used in order to evaluate the small bowel loops and the associated mesenteric findings, as well as to evaluate other abdominal organs. They both also can detect signs of disease activity, fibrosis, penetrating disease, and complications. The interpretation of such changes is essential to the multidisciplinary approach, as is the standardization of the nomenclature employed in the reports. In this paper, we review and illustrate the imaging findings of Crohn's disease, using the standardized nomenclature proposed in the multidisciplinary consensus statement issued by the Society of Abdominal Radiology, the Society of Pediatric Radiology, and the American Gastroenterology Association, with recommendations for descriptions, interpretations, and impressions related to those findings.

Comparison of 68Ga-DOTATOC and 18F-FDG Thoracic Lymph Node and Pulmonary Lesion Uptake Using PET/CT in Postprimary Tuberculosis

Tuberculosis (TB) remains one of the world's leading infectious cause of morbidity and mortality. Positron emission tomography (PET) associated with computed tomography (CT) allows a structural and metabolic evaluation of TB lesions, being an excellent noninvasive alternative for understanding its pathogenesis. DOTATOC labeled with gallium-68 (68Ga-DOTATOC) can bind to somatostatin receptors present in activated macrophages and lymphocytes, cells with a fundamental role in TB pathogenesis. We describe 68Ga-DOTATOC uptake distribution and patterns in thoracic lymph nodes (LN) and pulmonary lesions (PL) in immunocompetent patients with active postprimary TB, analyze the relative LN/PL uptake, and compare this two tracer's uptake. High uptake of both radiotracers in PL and LN was demonstrated, with higher LN/PL ratio on 68Ga-DOTATOC (P < 0.05). Considering that LN in immunocompetent patients are poorly studied, 68Ga-DOTATOC can contribute to the understanding of the complex immunopathogenesis of TB.

Computed tomography findings in a Brazilian cohort of 48 patients with pneumonia due to coronavirus disease

INTRODUCTION

This study was conducted to retrospectively review chest computed tomography (CT) findings in a Brazilian cohort of patients with pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

Chest CT scans of 78 patients with confirmed coronavirus disease (COVID-19), obtained in March and April 2020, were reviewed. Of 78 cases, the CT scans of 48 (61.5%) showed lung opacities. CT opacity features, their distribution, and the extent of infiltration were evaluated.

RESULTS

The most common CT findings were ground-glass opacities (97.9%), crazy-paving pattern (58.3%), and mixed pattern (18.8%). Rounded lung opacities were observed most frequently (70.8%). Other findings were cystic airspace changes (37.5%), vascular dilatation (35.4%), and the organizing pneumonia pattern (14.6%). The findings were frequently bilateral (87.5%), symmetrical (68.9%), and peripheral (60.2%).

CONCLUSIONS

The most common CT findings were ground-glass opacities and the crazy-paving pattern. Involvement was mostly bilateral, symmetrical, and peripheral. Round opacity morphology was frequently observed and might have some degree of specificity to viral COVID-19 pneumonia.

Incidence and morphological characteristics of the reversed halo sign in patients with acute pulmonary embolism and pulmonary infarction undergoing computed tomography angiography of the pulmonary arteries

OBJECTIVE

To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS.

METHODS

We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients).

RESULTS

Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS.

CONCLUSIONS

A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Endemic pulmonary fungal diseases in immunocompetent patients: an emphasis on thoracic imaging

INTRODUCTION

Systemic endemic mycoses are prevalent in specific geographical areas of the world and are responsible for high rates of morbidity and mortality in these populations, and in immigrants and travelers returning from endemic regions. The most common fungal infections that can affect the lungs of immunocompetent patients include histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, blastomycosis, sporotrichosis, aspergillosis, and cryptococcosis. Diagnosis and management of these diseases remain challenging, especially in non-endemic areas due to the lack of experience. Therefore, recognition of the various radiologic manifestations of pulmonary fungal infections associated with patients' clinical and epidemiologic history is imperative for narrowing the differential diagnosis. Areas covered: This review discusses the clinical and radiological findings of the main endemic fungal diseases affecting the lungs in immunocompetent patients. Specific topics discussed are their etiology, epidemiology, pathogenesis, clinical manifestations, methods of diagnosis, pathology and main imaging findings, especially in computed tomography. Expert commentary: Imaging plays an important role in the diagnosis and management of pulmonary fungal infection and may reveal useful signs. Although definitive diagnosis cannot be made based on imaging features alone, the use of a combination of epidemiologic, clinical and imaging findings may permit the formulation of an adequate differential diagnosis.

Chest magnetic resonance imaging: a protocol suggestion

In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI) has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation.

Organizing pneumonia: chest HRCT findings

OBJECTIVE:

To determine the frequency of HRCT findings and their distribution in the lung parenchyma of patients with organizing pneumonia.

METHODS:

This was a retrospective review of the HRCT scans of 36 adult patients (26 females and 10 males) with biopsy-proven organizing pneumonia. The patients were between 19 and 82 years of age (mean age, 56.2 years). The HRCT images were evaluated by two independent observers, discordant interpretations being resolved by consensus.

RESULTS:

The most common HRCT finding was that of ground-glass opacities, which were seen in 88.9% of the cases. The second most common finding was consolidation (in 83.3% of cases), followed by peribronchovascular opacities (in 52.8%), reticulation (in 38.9%), bronchiectasis (in 33.3%), interstitial nodules (in 27.8%), interlobular septal thickening (in 27.8%), perilobular pattern (in 22.2%), the reversed halo sign (in 16.7%), airspace nodules (in 11.1%), and the halo sign (in 8.3%). The lesions were predominantly bilateral, the middle and lower lung fields being the areas most commonly affected.

CONCLUSIONS:

Ground-glass opacities and consolidation were the most common findings, with a predominantly random distribution, although they were more common in the middle and lower thirds of the lungs.

Can chest high-resolution computed tomography findings diagnose pulmonary alveolar microlithiasis?

Objective

The present study was aimed at retrospectively reviewing high-resolution computed tomography (HRCT) findings in patients with pulmonary alveolar microlithiasis in order to evaluate the frequency of tomographic findings and their distribution in the lung parenchyma.

Materials and Methods

Thirteen patients (9 females and 4 males; age, 9 to 59 years; mean age, 34.5 years) were included in the present study. The HRCT images were independently evaluated by two observers whose decisions were made by consensus. The inclusion criterion was the presence of abnormalities typical of pulmonary alveolar microlithiasis at HRCT, which precludes lung biopsy. However, in 6 cases lung biopsy was performed.

Results

Ground-glass opacities and small parenchymal nodules were the predominant tomographic findings, present in 100% of cases, followed by small subpleural nodules (92.3%), subpleural cysts (84.6%), subpleural linear calcifications (69.2%), crazy-paving pattern (69.2%), fissure nodularity (53.8%), calcification along interlobular septa (46.2%) and dense consolidation (46.2%).

Conclusion

As regards distribution of the lesions, there was preferential involvement of the lower third of the lungs. No predominance of distribution in axial and anteroposterior directions was observed.

CT morphological features of the reversed halo sign in pulmonary paracoccidioidomycosis

OBJECTIVE

The purpose of this study was to identify morphological characteristics of the reversed halo sign (RHS) on chest CT in patients with pulmonary paracoccidioidomycosis (PCM) that may aid the diagnosis of this fungal disease.

METHODS

We retrospectively reviewed chest CT images from 23 patients with proven pulmonary PCM who demonstrated the RHS. Two chest radiologists analysed the morphological characteristics of the lesions and reached decisions by consensus.

RESULTS

We identified 64 RHSs on CT images from the 23 patients. Multiple lesions were observed in all cases, with middle and lower lung zone predominance occurring in 17 patients (73.9% of cases). 34 (53.1%) RHSs were round and 30 (46.9%) were oval. Outer borders of the RHSs were smooth in 32 (50%) lesions, nodular in 16 (25%) lesions and irregular/spiculated in 16 (25%) lesions. Ground-glass opacity was observed inside 63 (98.4%) lesions.

CONCLUSION

Our data suggest that morphological characteristics of the RHS on chest CT, such as the presence of multiple lesions, middle and lower lung zone predominance and a spiculated RHS ring, as well as the association with other parenchymal patterns, should lead radiologists to include PCM in the differential diagnosis of PCM in endemic areas.

ADVANCES IN KNOWLEDGE

This is the largest series of patients with RHS due to PCM and is also the first study to report RHS lesions with spiculated or irregular walls. The study adds information regarding morphological characteristics of the RHS that may raise suspicion of PCM on chest CT, particularly in endemic areas of the disease.

Influenza A (H1N1) pneumonia: HRCT findings

OBJECTIVE:

To describe aspects found on HRCT scans of the chest in patients infected with the influenza A (H1N1) virus.

METHODS:

We retrospectively analyzed the HRCT scans of 71 patients (38 females and 33 males) with H1N1 infection, confirmed through laboratory tests, between July and September of 2009. The HRCT scans were interpreted by two thoracic radiologists independently, and in case of disagreement, the decisions were made by consensus.

RESULTS:

The most common HRCT findings were ground-glass opacities (85%), consolidation (64%), or a combination of ground-glass opacities and consolidation (58%). Other findings were airspace nodules (25%), bronchial wall thickening (25%), interlobular septal thickening (21%), crazy-paving pattern (15%), perilobular pattern (3%), and air trapping (3%). The findings were frequently bilateral (89%), with a random distribution (68%). Pleural effusion, when observed, was typically minimal. No lymphadenopathy was identified.

CONCLUSIONS:

The most common findings were ground-glass opacities and consolidations, or a combination of both. Involvement was commonly bilateral with no axial or craniocaudal predominance in the distribution. Although the major tomographic findings in H1N1 infection are nonspecific, it is important to recognize such findings in order to include infection with the H1N1 virus in the differential diagnosis of respiratory symptoms.

Computed tomography findings in patients with H1N1 influenza A infection

The present study aimed to review high resolution computed tomography findings in patients with H1N1 influenza A infection. The most common tomographic findings include ground-glass opacities, areas of consolidation or a combination of both patterns. Some patients may also present bronchial wall thickening, airspace nodules, crazy-paving pattern, perilobular opacity, air trapping and findings related to organizing pneumonia. These abnormalities are frequently bilateral, with subpleural distribution. Despite their nonspecificity, it is important to recognize the main tomographic findings in patients affected by H1N1 virus in order to include this possibility in the differential diagnosis, characterize complications and contribute in the follow-up, particularly in cases of severe disease.

Extramedullary haematopoiesis: An uncommon posterior mediastinal mass

A 59-year-old man presented with anaemia and complaints of abdominal pain, weight loss, fatigue and dizziness. Computed tomography (CT) scans of the chest revealed bilateral paravertebral masses. The CT features were typical of extramedullary haematopoiesis (EMH). EMH should be strongly considered in a patient with bilateral, well-marginated, paravertebral thoracic masses and a history of chronic, severe anaemia.

Schistosoma mansoni-related morbidity in a low-prevalence area of Brazil: a comparison between egg excretors and seropositive non-excretors

In areas where there is a low prevalence of schistosomiasis mansoni, faecal examination is a relatively insensitive method of detection and infected people may also be missed because most show only mild morbidity. In such settings, serology may be a more useful diagnostic tool than microscopy. In the present study, the clinical and biochemical characteristics of individuals who were stool-positive for Schistosoma mansoni eggs were compared with those of individuals, from the same low-prevalence area of Brazil, who were stool-negative but seropositive for the parasite. Overall, 269 subjects were checked both for schistosome eggs in their faeces (using Kato-Katz smears and Lutz sedimentation) and for anti-S. mansoni IgG in their sera (using an ELISA). Although 128 (48%) of these subjects were found seropositive, only 26 (10%) were found to be egg excretors and two of the egg excretors were seronegative. Compared with the seropositive egg-negatives, the egg excretors had significantly higher frequencies of fatigue, melaena, jaundice and swelling of the abdomen. The egg excretors also had higher frequencies of hepatomegaly (20% v. 16%) and splenomegaly (4% v. 1%). In both groups of subjects, mean concentrations of serum proteins and haemoglobin and mean leucocyte counts were in the normal range whereas most blood concentrations of alanine aminotransferase and many of those of aspartate aminotransferase were slightly elevated. Although the egg excretors tended to have low-intensity infections, it seems possible that the seropositive nonexcretors had even milder infections that could not be detected by faecal examination. The high frequency of cure observed when the egg excretors were given praziquantel at 40 mg/kg (94%) is probably another indication that most had light infections when they were treated.

Mediastinite fibrosante: relato de caso

Neste trabalho é relatado o caso de uma mulher de 51 anos de idade, com dor torácica, dispneia e engurgitamento de vasos do tórax superior, sem evidências clínicas de doença granulomatosa. O estudo por imagem do tórax revelou massa mediastinal com calcificações, abordada por mediastinoscopia com biópsia. A análise histopatológica mostrou padrão inflamatório crônico sem etiologia definida, compatível com mediastinite fibrosante.

Microlitíase alveolar pulmonar: achados na tomografia computadorizada de alta resolução do tórax em 10 pacientes

OBJETIVO: Apresentar os achados na tomografia computadorizada de alta resolução (TCAR) do tórax da microlitíase alveolar pulmonar. MÉTODOS: Foram estudadas, retrospectivamente, as tomografias de dez pacientes adultos, sete mulheres e três homens, com idade média de 38,7 anos. Os exames foram analisados por dois radiologistas, de forma independente, e as decisões finais foram obtidas por consenso. RESULTADOS: Os achados mais freqüentes foram as opacidades em vidro fosco e as calcificações subpleurais, ambas presentes em 90% dos pacientes estudados. Os outros achados de maior relevância foram pequenos nódulos parenquimatosos, calcificação ao longo dos septos interlobulares, cissuras nodulares, nódulos subpleurais, cistos subpleurais, consolidações densas e padrão de pavimentação em mosaico. CONCLUSÕES: A microlitíase alveolar pulmonar apresenta aspectos na TCAR que são altamente sugestivos da doença, na maior parte dos casos dispensando a realização de biópsias pulmonares.

Pulmonary Paracoccidioidomycosis and AIDS

OBJECTIVE

To study the high-resolution computed tomographic (HRCT) findings in patients with AIDS and pulmonary paracoccidioidomycosis (PCM).

MATERIALS AND METHODS

The study included 5 consecutive patients (4 men and 1 woman, with ages ranging between 35 and 57 years; mean, 48 years) with diagnosis of AIDS and pulmonary PCM. All patients underwent HRCT, and the images were reviewed by 2 radiologists who reached decisions by consensus.

RESULTS

The predominant HRCT findings in the present series were large nodules (80%), cavited air-space consolidations (80%), ground-glass attenuation (80%), and cicatricial emphysema in the bases (80%). These lesions predominated bilaterally in the middle regions (80%) of the lungs.

CONCLUSIONS

The most common HRCT features in patients with AIDS and pulmonary PCM are large nodules associated with cavitated air-space consolidations and ground-glass attenuation, as well as cicatricial emphysema in the pulmonary bases. These findings are usually distributed bilaterally in the middle lung zones of the lungs.