Childhood interstitial lung disease (chILD) comprises a diverse group of rare disorders, which were previously poorly categorized on clinical, histologic, and pathogenic grounds. The classification of chILD introduced by the chILD Research Network has led to a systematic approach to identifying and categorizing these rare conditions. A multidisciplinary approach integrating clinical, radiologic, pathologic, and genetic findings enables accurate diagnosis in children with "pediatric interstitial pneumonia of uncertain cause." It has become apparent that chILDs are collectively frequent in pediatric practice, and prompt diagnosis can improve the outcomes of affected children. Since the clinical symptoms of chILDs are nonspecific, imaging using high-resolution CT plays a central role in the diagnostic approach to this diverse group of diseases. In most disorders, cellular infiltration and abnormal exudates commonly cause acute-phase imaging findings, such as centrilobular ground-glass opacities that are multifocal, geographic, and diffuse, as well as a crazy-paving appearance. Persistent inflammatory reactions lead to chronic-phase findings, including reticulation, lung cysts, and honeycombing with traction bronchiectasis. Small-airway compromise causes air trapping and a mosaic attenuation pattern. These imaging findings are individually nonspecific; however, meticulous integration of the diverse imaging findings allows a specific diagnosis to be reached. The authors review the current knowledge on the imaging findings associated with chILDs based on recent investigations of these conditions. ©RSNA, 2026 Supplemental material is available for this article.

BACKGROUND:Dual-type deep learning reconstruction (DLR) may improve the pancreatic MRI image quality; however, the effects of different DLR strengths at 1.5 T compared with the conventional 1.5 T and 3 T MRI without DLR remain unclear. PURPOSE:To evaluate the image quality of 1.5 T MRI reconstructed with different DLR strengths for pancreatic cystic lesions, compared with conventional 1.5 T and 3 T MRI without DLR. STUDY TYPE:Retrospective, single-center study. POPULATION:Ninety-nine patients with pancreatic cystic lesion (53 men, 46 women; age range, 29.2-93.8 years) underwent 1.5 T MRI; 54 had undergone 3 T MRI within the preceding 2 years. FIELD STRENGTH/SEQUENCE:1.5 T and 3 T MRI; axial single-shot turbo spin-echo T2-weighted imaging and heavily T2-weighted single-shot turbo spin-echo two-dimensional MRCP. The 1.5 T images were reconstructed using dual-type DLR with 80% and 50% denoising levels and compressed sensing (CS) without DLR. The 3 T images used CS without DLR. ASSESSMENT:Three blinded radiologists independently assessed eight image-quality items using a 5-point Likert scale. Signal-to-noise ratio, contrast-to-noise ratio, and edge rise distance were measured. STATISTICAL TESTS:Friedman tests followed by Wilcoxon signed-rank tests with Holm correction were used. RESULTS:At 1.5 T, 80% DLR yielded significantly higher scores than CS for all qualitative items except for texture naturalness with higher SNR (40.20 vs. 23.23) and CNR (24.67 vs. 13.57) and lower ERD (1.59 vs. 1.98 mm). ERD did not differ between 80% and 50% DLR (p = 0.825). Compared with 3 T CS, 1.5 T 80% DLR showed significantly higher scores for seven of eight items, significantly higher SNR and CNR, and lower ERD (39.69 vs. 30.62; CNR, 24.33 vs. 16.17; and 1.49 vs. 2.16 mm, respectively). Texture naturalness was significantly lower with 80% DLR, indicating a trade-off between image enhancement and naturalness. DATA CONCLUSION:In this exploratory, non-simultaneous comparison, 1.5 T DLR showed favorable image-quality metrics relative to 3 T CS without DLR. EVIDENCE LEVEL:3. TECHNICAL EFFICACY:Stage 1.

ABSTRACT A 55‐year‐old man with idiopathic eosinophilic pneumonia developed rapidly progressive dendriform pulmonary ossification with branching pulmonary calcifications on CT. Corticosteroid treatment improved both pulmonary consolidations and calcified lesions, suggesting that acute or immature pulmonary calcification may be reversible.

BACKGROUND:Progressive pulmonary fibrosis (PPF) is a critical concern in interstitial lung disease (ILD) management. The HAL score, which incorporates honeycombing (H), age >75 years (A), and serum lactate dehydrogenase >222 U/L (L), can predict acute exacerbations in patients with idiopathic interstitial pneumonia (IIP). This study aims to evaluate the predictive utility of the HAL score for PPF development. METHODS:This study was a post-hoc analysis of a multicenter prospective cohort study involving patients with IIP. PPF was diagnosed if at least two of the following three criteria were met: worsening respiratory symptoms, radiological progression, and physiological progression. RESULTS:Among the 144 patients, 29 (22.3%) developed PPF during the observation period. Among the three criteria for PPF, a higher HAL score significantly correlated with worsening respiratory symptoms (p = 0.001) and radiological progression (p = 0.022), but not with physiological progression (p = 0.717). Therefore, a higher HAL score significantly correlated with an increased PPF risk (12.5% for a score of 0, 25.9% for a score of 1, and 33.3% for a score of ≥2; p = 0.032). The HAL score also correlated with overall survival (p < 0.001). For the 92 patients (70.8%) with non-idiopathic pulmonary fibrosis (IPF), the HAL score was significantly associated with PPF development (p = 0.021), while not for the 38 patients (29.2%) with IPF (p = 0.872). CONCLUSION:In patients with non-IPF, the HAL score correlated with PPF development and could be useful to monitor those patients and to avoid missed treatment opportunities.

BACKGROUND: Internal thoracic artery aneurysms are exceptionally rare and carry a risk of fatal rupture. Although pseudoaneurysms are commonly associated with trauma or surgical interventions, the development of true aneurysms promoted by thrombotic disorders has not been previously reported. CASE PRESENTATION: A 61-year-old man undergoing hemodialysis for end-stage renal disease due to untreated nephrotic syndrome presented with hemoptysis. He had a medical history of deep vein thrombosis and was taking warfarin. Imaging studies revealed pulmonary embolism, systemic collateral circulation, a 21-mm aneurysm of the left internal thoracic artery, and a 9-mm aneurysm of the left bronchial artery. Laboratory investigations confirmed acquired protein S deficiency, likely caused by nephrotic syndrome. The internal thoracic artery aneurysm, due to concern for rupture, was successfully treated with percutaneous catheter arterial embolization, while the left bronchial arterial aneurysm was managed conservatively without intervention because of its small size. The patient recovered without complications and remained stable during a 5-year follow-up. CONCLUSIONS: This case highlights a rare presentation of internal thoracic artery aneurysm coinciding with acquired protein S deficiency and nephrotic syndrome. Although a direct causal relationship between protein S deficiency and aneurysm formation is difficult to establish, the co-occurrence of these conditions underscores the importance of careful vascular assessment in similar patients.

Bronchoalveolar lavage (BAL) is crucial for the diagnosis of interstitial lung disease (ILD). Although BAL lymphocytosis is found in patients with connective tissue disease (CTD)-related ILD, the effects of CTD-associated features on BAL lymphocytosis have not been elucidated. To identify CTD-associated features that affect BAL lymphocyte fraction in patients with idiopathic interstitial pneumonia (IIP). This post hoc analysis of a prospective, multicentre cohort study was conducted between 2015 and 2020. Overall, 222 patients newly diagnosed with IIP were consecutively enrolled, and 74 autoimmune features were comprehensively analysed during IIP diagnosis. The median age was 71 years, and the median observation period was 36 months. The clinical characteristics related to a significant increase in BAL lymphocyte fraction were consolidation opacity on high-resolution computed tomography (HRCT), morphologic domain of interstitial pneumonia with autoimmune features (IPAF), serum CXCL10 concentration, and acute/subacute onset (all p < 0.05). In contrast, presence of joint lesion/mucocutaneous lesion/dry symptoms, autoantibodies, or other CTD-like features on HRCT and surgical lung biopsy did not affect the BAL lymphocyte fraction (all p ≥ 0.05). Furthermore, a high BAL lymphocyte fraction (≥ 8.5%) was related to a low proportion of progressive pulmonary fibrosis (p < 0.001) and favourable survival (log-rank, p = 0.020) in patients with non-idiopathic pulmonary fibrosis (IPF). IPAF morphologic domain especially with consolidation opacity on HRCT and high CXCL10 concentration, but not CTD-like symptoms, autoantibodies, or CTD-like features on lung biopsy, were related to a high BAL lymphocyte fraction with favourable survival in patients with non-IPF.

Background: Patients with idiopathic interstitial pneumonia (IIP) have a favourable prognosis when they have interstitial pneumonia with autoimmune features (IPAF). However, precise IPAF-related findings from high-resolution computed tomography (HRCT) and lung histopathological specimens and the treatment response have not been fully determined. Therefore, this study was conducted to evaluate the relationship between findings on HRCT or lung histopathological specimens and the progression of interstitial pneumonia in patients with IPAF. Methods: This multicentre cohort study prospectively enrolled consecutive patients with IIP. At the diagnosis of IIP, we systematically evaluated 74 features suggestive of connective tissue diseases and followed them up. HRCT, lung specimens, serum antibodies, and the clinical course were also evaluated. Results: Among 222 patients with IIP, 26 (11.7%) fulfilled the IPAF criteria. During a median observation period of 36 months, patients with IPAF showed better survival than those without IPAF (p = 0.034). While histopathological findings were not related to IPAF, nonspecific interstitial pneumonia (NSIP) with organizing pneumonia (OP) overlap was the most prevalent HRCT pattern (p < 0.001) and the consolidation opacity was the most common radiological finding in IPAF (p = 0.017). Furthermore, in patients with IPAF, the diagnosis of COP or NSIP with OP overlap was associated with a higher increase in %FVC in 1 year than in those with idiopathic pulmonary fibrosis, NSIP, or unclassifiable IIP (p = 0.002). Conclusions: This study shows the presence of consolidation opacity on HRCT and the diagnosis of COP or NSIP with OP overlap are associated with IPAF and its favourable treatment response in patients with IPAF.

Background: Usual interstitial pneumonia (UIP) cases without honeycombing (possible UIP) included various CT features and was often difficult to diagnose. Purpose: This study aimed to classify the cases with possible UIP on CT features using cluster analysis and evaluate the features of subsets of participants and the correlation of prognosis. Materials and Methods: The study included 85 patients with possible UIP in the 2011 idiopathic pulmonary fibrosis (IPF) guideline with radiological diagnosis. All cases underwent surgical biopsies and were diagnosed by multidisciplinary discussion (MDD) from the nationwide registry in Japan. The readers evaluated pulmonary opacity, nodules, cysts, and predominant distribution which were reclassified by IPF guidelines in 2018. Additionally, cases were classified into four groups by cluster analysis based on CT findings. The differences in survival among IPF classification and the clusters were evaluated. Results: Cases were diagnosed as IPF (n = 55), NSIP (n = 4), unclassifiable (n = 23), and others (n = 3) by MDD. Cluster analysis revealed 4 clusters by CT features (n = 47, 16, 19 and 3, respectively). Cluster 1 had fewer lesions overall. Cluster 2 have many pure ground-glass opacities and ground-glass opacities with reticulation. Cluster 3 had many reticular opacities and nodules with few lower predominant distributions. Cluster 4 was characterized by peribronchovascular consolidation.The mean survival time of cluster 1 (4518 days) was significantly better than cluster 2, 3, and 4 (1843, 2196, and 1814 days, respectively) (p = 0.03). Conclusion: In conclusion, UIP without honeycombing included various CT patterns and MDD diagnoses. Significangly differences in prognosis were observed among clusters classified by CT findings.

Airway-centered fibroelastosis is characterized by peribronchovascular fibroelastosis, predominantly in the upper lobes, with little-to-no pleural involvement. In this study, we describe two cases of airway-centered fibroelastosis diagnosed based on radiological and pathological findings. The first case comprised a 44-year-old man whose forced vital capacity improved over three months following treatment with nintedanib. The second case involved a 50-year-old woman who was treated with oral corticosteroids but yielded an unfavorable outcome. An effective treatment for airway-centered fibroelastosis has not yet been identified; therefore, this study may help contribute to a more thorough discussion regarding treatment strategies for this disease.

Interstitial pneumonia with autoimmune features (IPAF), which does not meet any of the criteria for connective tissue diseases (CTD), has been attracting an attention in patients with idiopathic interstitial pneumonia (IIP). However, the biomarkers that reflect the clinical course of these patients have not been fully elucidated. To identify useful serum biomarkers reflecting CTD-related features and favorable prognoses in patients with IIP. This was a post hoc analysis of a prospective and multicenter cohort study between 2015 and 2020. Newly diagnosed patients with IIP were consecutively enrolled, and 74 autoimmune features and autoantibodies were comprehensively checked during IIP diagnosis. Serum levels of CXCL10, CXCL1, CCL2, BAFF, angiopoietin-2, and leptin were evaluated at the time of IIP diagnosis. Two hundred twenty-two patients (159 men and 63 women) with IIP were enrolled. The median observation duration was 36 months. The median age was 71 years old, and median

A 44-year-old man presented with a chief complaint of constipation. Initial contrast-enhanced CT showed extensive bowel wall thickening, mainly in the left colon, with a thin cord-like inferior mesenteric vein (IMV), in contrast to ectatic mesenteric venous branches, suggesting bowel ischaemia owing to venous stasis. One month later, at the time of symptom exacerbation, CT angiography showed a cord-like IMV and ectatic mesenteric venous branches with early enhancement, suggesting the presence of an arteriovenous fistula (AVF). Owing to the progression of bowel ischaemia and necrosis with peritonitis, emergency surgery was performed. Surgical specimens showed focal myointimal hyperplasia of the proximal mesenteric veins in both ischaemic and non-ischaemic lesions of the resected colon, thus leading to the diagnosis of idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) when combined with the clinical and imaging findings. IMHMV is a bowel ischaemic disease caused by non-thrombotic venous obstruction that requires bowel resection and has been suggested to be associated with AVF. Cord-like IMV and AVF in the mesentery are important CT findings that characterize IMHMV. CT angiography is useful in diagnosing IMHMV.

Invasive candidiasis is rare but is associated with high mortality in immunocompromised or critically ill patients. Here, we present a case of a 55-year-old man with untreated diabetes who was diagnosed with coronavirus disease 2019 and subsequently developed invasive candidiasis. The patient presented with fever, tachycardia, and tachypnea. Chest computed tomography revealed multiple consolidations mainly distributed around the bronchovascular bundles with bronchiectatic cavity formation, which initially raised suspicion for invasive pulmonary aspergillosis. However, subsequent testing confirmed Candida albicans infection; hence, we changed the antifungal agents effective for invasive candidiasis. This improved the patient's respiratory status, and he was then successfully weaned from mechanical ventilation. This case report highlights the importance of considering invasive candidiasis in the differential diagnosis of patients with bronchiectatic cavities on chest computed tomography, particularly in immunocompromised or critically ill patients with risk factors for invasive candidiasis.

Background:The radiographic features of Mycobacterium avium complex pulmonary disease (MAC-PD), a major component of nontuberculous mycobacteria, consist of a variety of lesions; however, the responsiveness of each type of radiographic factor to treatment is unclear. Thus, we evaluated the longitudinal changes of each factor in serial computed tomography (CT) images using a mixed-effects model, and investigated the radiographic transition in patients with MAC-PD whose progress could be followed. Methods:In this retrospective study, eighty-four patients diagnosed with MAC-PD and with yearly CT records were recruited after a review of 328 medical records with culture-positive MAC in respiratory specimens. The study participants were divided into two groups: treatment (n = 43) and no-treatment (n = 41) groups. Radiographic images were scored using the nodule (N), infiltration (I), cavity (C), ectasis (E) scoring system. Longitudinal changes in each radiographic lesion factor were analyzed using a mixed-effects model in treated and untreated patients. Results:All factors tended to progress without treatment, and significant longitudinal changes were observed in the N, I, and E factors (N: p = 0.010, I: p = 0.004, E: p < 0.001). Although treatment tended to improve N and I in radiographic images (N: p = 0.006, I: p = 0.203), cavities and ectasis progressed, regardless of treatment (C: p = 0.057 and E: p = 0.033). Conclusion:Radiographic changes of MAC-PD can be categorized into reversible (nodules and infiltrations) and irreversible (cavities and ectasis) lesions. Early treatment may prevent the accumulation of irreversible factors.

A 15-year-old girl presented with severe chest and back pain after sustaining high-energy trauma from a motorcycle accident. Contrast-enhanced computed tomography (CT) revealed multiple ring-shaped spherical nodules (1 – 2cm in diameter) diffusely distributed throughout the upper and lower lobes of both lungs and along the bronchovascular bundles (Figure 1). Positron emission tomography – CT imaging, performed because of dif fi culty in diagnosing the nodules via CT, revealed relatively strong

Cystic fibrosis is an autosomal recessive genetic disorder that damages the exocrine function of the body, resulting in alterations of multiple organs. In the respiratory system, it is known to cause bronchiectasis, recurrent bronchitis, and pneumonia; however, to the best of our knowledge, there are no reported cases of pulmonary arteriovenous malformations associated with this disease. Herein, we report a case of cystic fibrosis with multiple pulmonary arteriovenous malformations. A 16-year-old girl, who has been monitored since childhood for pancreatitis of unknown cause, experienced respiratory symptoms and hypoxemia (PaO2 = 57 mmHg). At 13 years of age, chest computed tomography revealed bronchiectasis, bronchial wall thickening, and tree-in-bud sign. Genetic testing was performed, and the patient was diagnosed with cystic fibrosis. However, the computed tomography scan also showed incidental nodular lesions in the left superior and both the inferior pulmonary lobes, suggesting multiple arteriovenous malformations. Dynamic computed tomography was performed which, confirmed the presence of 3 pulmonary arteriovenous malformations. Coil embolization was performed on all lesions, and the hypoxemia was corrected. Marked hypoxemia in a patient with cystic fibrosis may not be explained only by the presence of bronchiectasis and/or bronchial wall thickening; in such cases, it may be necessary to examine possible additional findings on computed tomography images, such as arteriovenous malformations.

Background Massive hemoptysis after thoracic aortic aneurysm (TAA) repair is a rare but potentially lethal condition. Endovascular management is a challenging treatment option due to the complexity of culprit vessel access. Case presentation An 81-year-old woman was referred to our hospital with massive hemoptysis. She had a history of graft replacement and thoracic endovascular aortic repair (TEVAR) for dissecting TAA. Computed tomography (CT) showed massive atelectasis with hematoma in the left lower lung lobe adjacent to the descending aortic aneurysm treated with TEVAR. Contrast-enhanced CT revealed a pseudoaneurysm and proliferation of abnormal vessels at the peripheral side of the left pulmonary ligament artery (PLA) in the atelectasis. The PLA continued to the right subscapular artery via a complex collateral pathway. Diagnostic angiography of the right subcapsular artery revealed a pseudoaneurysm and abnormal vessels at the peripheral side of the left PLA with a systemic-pulmonary artery shunt. Transcatheter arterial embolization (TAE) for the left PLA via the collateral pathway with N -butyl cyanoacrylate achieved complete embolization. The patient’s hemoptysis was controlled and she was discharged. Conclusions Here we presented a case of massive hemoptysis due to PLA disruption that occurred after TAA repair. TAE via a complex collateral pathway is a feasible and effective treatment for hemoptysis, even in patients who have undergone surgical or endovascular TAA repair.