Segmentation-Based Analysis of T2- and T1-Weighted Dynamic Magnetic Resonance Images Provides Adequate Observer Agreement in the Evaluation of Interstitial Lung Disease.

OBJECTIVE: The aim of the study is to quantify observer agreement in the magnetic resonance imaging (MRI) classification of inflammatory or fibrotic interstitial lung disease (ILD). METHODS: Our study is a preliminary analysis of a larger prospective cohort. The MRI images of 18 patients with ILD (13 females; mean age, 65 years) were acquired in a 1.5 T scanner and included axial fat-saturated T2-weighted (T2-WI, n = 18) and coronal fat-saturated T1-weighted images before and 1, 3, 5, and 10 minutes after gadolinium administration (n = 16). The MRI studies were evaluated with 2 different methods: a qualitative evaluation (visual assessment and measurement of few regions of interest; evaluations were performed independently by 5 radiologists and 3 times by 1 radiologist) and a segmentation-based analysis with software extraction of signal intensity values (evaluations were performed independently by 2 radiologists and twice by 1 radiologist). Interstitial lung disease was classified as inflammatory or fibrotic, based on previously described imaging criteria. RESULTS: Regarding the qualitative evaluation, intraobserver agreement was excellent (κ = 0.92, P < 0.05) for T2-WI and fair (κ = 0.29, P < 0.05) for T1 dynamic study, while interobserver agreement was moderate (κ = 0.56, P < 0.05) and poor (κ = 0.11, P = 0.18), respectively. In contrast, upon segmentation-based analysis, intraobserver and interobserver agreement were excellent for T2-WI (κ = 0.886, P < 0.001; κ = 1.00, P < 0.001; respectively); for T1-WI, intraobserver agreement was excellent (κ = 0.87, P < 0.05) and interobserver agreement was good (κ = 0.75, P < 0.05). CONCLUSIONS: Segmentation-based MRI analysis is more reproducible than a qualitative evaluation with visual assessment and measurement of few regions of interest.

Pulmonary diseases with imaging findings mimicking aspergilloma.

Patients with preexisting lung cavities are at risk of developing intracavitary fungal colonization. Because Aspergillus spp. are the most commonly implicated fungi, these fungal masses are called aspergillomas. Their characteristic "ball-in-hole" appearance, however, may be found in a variety of other conditions that can produce radiologic findings mimicking aspergilloma. In this paper, we review the main diseases that may mimic the radiographic findings of aspergilloma, with brief descriptions of clinical, radiologic, and histopathologic findings.

Fungal diseases mimicking primary lung cancer: radiologic-pathologic correlation.

A variety of fungal pulmonary infections can produce radiologic findings that mimic lung cancers. Distinguishing these infectious lesions from lung cancer remains challenging for radiologists and clinicians. In such cases, radiographic findings and clinical manifestations can be highly suggestive of lung cancer, and misdiagnosis can significantly delay the initiation of appropriate treatment. Likewise, the findings of imaging studies cannot replace the detection of a species as the aetiological agent. A biopsy is usually required to diagnose the infectious nature of the lesions. In this article, we review the clinical, histologic and radiologic features of the most common fungal infections that can mimic primary lung cancers, including paracoccidioidomycosis, histoplasmosis, cryptococcosis, coccidioidomycosis, aspergillosis, mucormycosis and blastomycosis.

Normal variance in emphysema index measurements in 64 multidetector-row computed tomography.

The purpose of this study was to identify the normal variance of emphysema index (EI) measured in examinations acquired with 64 multidetector-row computed tomography (64-MDCT). A longitudinal, noninterventional study was performed retrieving all patients in our institution who are currently registered in our lung nodule protocol. All patients with clinical, functional, or significant radiological changes were excluded. We assumed that EI should remain unchanged within a short period of time. We reviewed 475 MDCTs in order to select 50 clinically stable patients who had two sequential chest MDCTs performed within a time interval of less than three months, and who presented at least one lung free of abnormalities but emphysema. CT densitovolumetry was used to calculate EI with thresholds set at -950 Hounsfield units (HUs) (EI-950) and -970 HUs (EI-970); on both studies from each patient. We observed the variation of total lung volume (TLV), mean lung density (MDL), and EI for measurements at the baseline and at follow-up scans. Differences observed between baseline and follow-up measurements were: TLV µ= 149 ml; IC = µ +1.96 (133); EI-950 µ = 0.02%; p 95 = 0.89%; EI-970 µ = 0.04%; p 95 = 0.23% and MLD µ = 15 HU; IC = µ +1.96 (18). The correlations obtained were the following: TLV r = 0.96, EI-950 r = 0.79, EI-970 r = 0.85. Accepting that emphysema would remain unchanged within three months on stable patients, differences of less than 0.89% for EI-950 and of less than 0.23% for EI-970 are within the variance of the method.

Lung Magnetic Resonance Imaging for Prediction of Progression in Patients With Nonidiopathic Pulmonary Fibrosis Interstitial Lung Disease: A Pilot Study.

PURPOSE: Correlate magnetic resonance imaging (MRI) parameters at baseline with disease progression in nonidiopathic pulmonary fibrosis interstitial lung disease (ILD). MATERIALS AND METHODS: Prospective observational cohort study, in which patients with non-idiopathic pulmonary fibrosis ILD underwent MRI at baseline (1.5 T). T2-weighted images (T2-WI) were acquired by axial free-breathing respiratory-gated fat-suppressed "periodically rotated overlapping parallel lines with enhanced reconstruction" and T1-weighted images (T1-WI) by coronal end-expiratory breath-hold fat-suppressed "volumetric interpolated breath-hold examination" sequences, before and at time points T1, T3, T5, and T10 minutes after gadolinium administration. After MRI segmentation, signal intensity values were extracted by dedicated software. Percentage of the ILD volume and a ratio between signal intensity of ILD (SIILD) and normal lung (SInormal lung) were calculated for T2-WI; percentage of signal intensity (%SI) at each time point, time to peak enhancement, and percent relative enhancement of ILD in comparison with normal lung (%SIILD/normal lung) were calculated for T1-WI. MRI parameters at baseline were correlated with diagnosis of disease progression and variation in percent predicted forced vital capacity (%FVC) and diffusing capacity of the lung for carbon monoxide after 12 months. RESULTS: Comprehensive MRI evaluation (T2-WI and T1-WI) was performed in 21 of the 25 patients enrolled (68% females; mean age: 62.6 y). Three of the 24 patients who completed follow-up fulfilled criteria for disease progression. Baseline T2-WI SIILD/SInormal lung was higher for the progression group (P = 0.052). T2-WI SIILD/SInormal lung and T1-WI %SIILD/normal lung at T1 were positively correlated with the 12-month variation in %FVC (r = 0.495, P = 0.014 and r = 0.489, P= 0.034, respectively). CONCLUSIONS: Baseline MRI parameters correlate with %FVC decline after 12 months.

Chemical-shift MRI of pulmonary hamartomas: initial experience using a modified technique to assess nodule fat.

OBJECTIVE: The aim of this study was to show the usefulness of chemical-shift MRI in the diagnosis of intranodular fat in seven patients with pulmonary hamartomas and indeterminate CT findings. CONCLUSION: In the setting of chemical-shift MRI, the average nodule signal intensity index of pulmonary hamartomas was 45.3% (SD = 25.5%). The correlation between average nodule signal intensity and CT attenuation in Hounsfield units was -0.94. Chemical-shift MRI could be an important tool for the detection of fat in pulmonary hamartomas with inconclusive CT findings.

Reversed halo sign on computed tomography: state-of-the-art review.

The reversed halo sign (RHS) is a chest computed tomography (CT) pattern defined as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation. The RHS was first described as being relatively specific for cryptogenic organizing pneumonia but was later observed in several other infectious and noninfectious diseases. Although the presence of the RHS on CT may help narrow the range of diseases considered in differential diagnoses, final diagnoses should be based on correlation with the clinical scenario and the presence of additional disease-specific CT findings. However, frequently a biopsy may be needed to establish the diagnosis. Organizing pneumonia is the most frequent cause of the RHS. This is a distinct clinical and pathologic entity that can be cryptogenic or secondary to other known causes. Morphologic aspects of the halo, particularly the presence of small nodules in the wall or inside the lesion, usually indicate an active granulomatous disease (tuberculosis or sarcoidosis) rather than organizing pneumonia. Immunocompromised patients presenting with the RHS on CT examination should be considered to have an infection until further analyses prove otherwise. Pulmonary zygomycosis and invasive pulmonary aspergillosis are typically seen in patients with severe immunosuppression, most commonly secondary to hematological malignancies. Other causes of the RHS include noninvasive fungal infections such as paracoccidioidomycosis, histoplasmosis, and Pneumocystis jiroveci pneumonia. Furthermore, Wegener's granulomatosis, radiofrequency ablation, and lymphomatoid granulomatosis may also lead to this finding. Based on a search of the PubMed and Scopus databases, we review the different diseases that can manifest with the RHS on CT.

Pictorial Review of Thoracic Parasitic Diseases: A Radiologic Guide.

Parasitoses are infectious diseases of global distribution, with predominance in areas of poor sanitation. Parasites cause damage through direct tissue injury and the inflammatory response generated by their migration and establishment in various organs. Thoracic involvement by parasitic disease can generate both specific and nonspecific clinical, laboratorial, and radiologic manifestations, which often makes their diagnosis challenging. The correct diagnosis is crucial for definition of treatment, which sometimes requires rapid intervention. Based on a literature review of the last few decades, this article aimed to characterize the main radiologic findings related to thoracic manifestations of parasitic diseases, correlating them with radiographic and tomographic images of patients with confirmed diagnosis of such pathologies. The included parasitic diseases are malaria, Chagas disease, toxoplasmosis, amoebiasis, ascariasis, toxocariasis, strongyloidiasis, dirofilariasis, cysticercosis, echinococcosis, schistosomiasis, and paragonimiasis.

Computed tomography measurement of lung volume in preoperative assessment for living donor lung transplantation: volume calculation using 3D surface rendering in the determination of size compatibility.

The objective of this study was to describe the use of CT volume quantification assessment of candidates for LLDLT. Six pediatric candidates for LDLLT and their donors were investigated with helical chest CT, as part of the preoperative assessment. The CT images were analyzed as per routine and additional post-processing with CT volume quantification (CT densitovolumetry) was performed to assess volume matching between the lower lobes of the donors and respective lungs of the receptors. CT images were segmented by density and region of interest, using post-processing software. Size matching was also assessed using the FVC formula. Compatible volumes were found in three cases. The other three cases were considered incompatible. All three recipients with compatible sizes survived the procedure and are alive and well. One patient with incompatible size was submitted to the procedure and died because of complications attributed to the incompatible volumes. One patient with incompatible size has subsequently grown and new measurements are to be taken to check the current volumes. Different donors are being sought for the remaining patient whose lung volumes were considered too big for the prospective transplant donor lobes. Under FVC formula criteria, all cases were considered compatible. CT volume quantification is an easy to perform, non-invasive technique that uses CT images for the preassessment of candidates for LDLLT, to compare the volume of the lower lobes from the donors with volume of each lung in the prospective recipients. Size matching based on CT densitovolumetry and FVC may differ.

Clubbed fingers: radiological evaluation of the nail bed thickness.

It is established that there is an increase in soft tissue of the clubbed digits as demonstrated on previous histopathological examinations. In the present study, the nail bed thickness was assessed and measured on plain radiographs of index fingers in two groups of patients: one group with lung disease and fingers clubbing and one group of normal controls. A vertical x-ray beam was used with a focus-film distance of 1.0 m, with the index finger placed in lateral view directly over the film, without anti-diffusion grid. Three investigators, blinded to prevent bias measured the thickness of soft tissues between the nail root and the terminal phalanx on the radiographs. This method was used to evaluate a group of 85 clinically clubbed (hyponychial angle > 192.0 degrees) adult patients with lung disease and a control group of a 100 normal adult individuals with no clubbing (hyponychial angle < 188.0 degrees). The mean nail bed thickness in the patients with clubbing (n = 85) was 3.88 +/- 0.55 mm (3.00-5.50 mm). In comparison, in the normal subjects (n = 100), the mean was 2.38 +/- 0.27 mm (1.75-3.10 mm), revealing a significant difference (P < 0.001). Only two normal individuals presented nail bed thickness >or=3.0 mm. A good interobserver agreement on the measurements was found (P > 0.900). The radiographic evaluation of the nail bed thickness was easily performed, with good interobserver concordance. It is possible to distinguish between clubbed from nonclubbed fingers, in vivo, using plain radiograph.

Multidetector Computed Tomography Findings in Pulmonary Hamartomas: A New Fat Detection Threshold.

PURPOSE: The aim of the study was to determine the accuracy of multidetector computed tomography in the evaluation of histologically confirmed pulmonary hamartomas (PHs), with a special focus on fat detection. MATERIALS AND METHODS: Data from 55 patients who had received a histologically confirmed diagnosis of PH and had undergone 64-slice thoracic MDCT were retrospectively evaluated. RESULTS: PHs manifested predominantly as peripheral pulmonary nodules with lobulated margins. The average lesion diameter was 1.51 cm (SD 0.6 cm). Histologic analyses identified fat content in 43/55 (78.2%) surgical specimens. The accuracy, sensitivity, and specificity of fat detection at a density threshold of -40 HU were 83.7%, 100%, and 87.2%, respectively. A threshold of -33 HU yielded better results (95.3%, 100%, and 96.3%, respectively). Popcorn-like calcifications were found in only 12/55 (21.8%) PHs and were the only imaging feature suggestive of PH in 7.2% of cases. Most (66%) lesions with popcorn-like calcifications also contained fat. CONCLUSIONS: The adoption of a new threshold for fat content (<-33 HU) can lead to further improvements in the overall ability to detect PHs by CT.

Computed tomographic pulmonary changes in patients with chronic rhinosinusitis.

OBJECTIVE: To investigate whether patients with a diagnosis of chronic rhinosinusitis (CRS) show characteristic pulmonary changes on chest CT compared with a control group without sinusopathy. METHODS: This retrospective, observational study included patients with and without a diagnosis of CRS who underwent CT examination of the lungs between 2012 and 2014. Two radiologists, who were blinded for the presence of CRS, reviewed the scans for the presence of any abnormalities consensually. The χ(2) test was used for correlative analysis, with a significance level of 0.05. RESULTS: A total of 123 CT series (51.2% from male patients, mean age 41 ± 16 years) were reviewed, including those from 59 (48%) patients with a diagnosis of CRS. Patients with CRS were more likely than the control group to exhibit atelectasis, bronchiolectasis, centrilobular nodules and ground-glass opacities (all p < 0.05), with a significant predilection for middle lobe and lingular involvement observed (p < 0.001). Other abnormalities, such as bronchial wall thickening and air trapping, did not differ between groups. CONCLUSION: Atelectatic changes, ground-glass opacities, bronchiolectasis and centrilobular nodules are the most frequent abnormalities associated with CRS, with peculiar middle lobe and lingular involvement observed on chest CT examinations. ADVANCES IN KNOWLEDGE: CRS is a frequent disorder that displays typical pulmonary changes at CT. The recognition of such findings can prevent patients with this condition from undergoing unnecessary investigations that might be based on the presence of the aforementioned radiological features.