Search Results (146)

Background/Objectives: The prognostic value of serial coronary artery calcium (CAC) progression remains uncertain in Asian populations and statin-treated patients. We evaluated the association between CAC progression and subsequent major adverse cardiovascular events (MACE) in a Taiwanese cohort. Methods: We retrospectively studied 1791 individuals undergoing two CAC-scoring cardiac CT scans at a tertiary center in Taiwan from 2006 to 2021, excluding those with MACE before the second scan. CAC progression was defined as an annualized Agatston score increase of ≥20 units/year. Time-to-event analyses used landmark Cox models beginning at the second scan, with inverse probability weighting (IPW), balance diagnostics, multivariable Cox regression, and multiple-imputation sensitivity analyses. Results: CAC progression occurred in 365 participants (20.4%). Progressors were older and had greater cardiometabolic risk and baseline CAC burden. In a landmark IPW analysis, CAC progression was associated with higher subsequent MACE risk (HR 2.02, 95% CI 1.49–2.74), with a graded association across annualized CAC change categories: HR 1.72 (95% CI 1.17–2.74) for 21–49 units/year and HR 2.86 (95% CI 2.29–3.57) for ≥50 units/year. The association remained consistent in multiple-imputation analysis (HR 1.90, 95% CI 1.36–2.66) and across major clinical subgroups. Discrimination for 10-year MACE was stronger among statin users than non-statin users (AUC 0.774 vs. 0.571), although statin-stratified analyses were exploratory. Conclusions: CAC progression was independently associated with subsequent MACE and showed a graded risk relationship. Serial CAC assessment may serve as a useful dynamic marker for refining longitudinal cardiovascular risk stratification, while prospective studies are needed to validate progression-guided management. Full article

Background: A combination of cyclin-dependent kinase 4/6 inhibitors (CDKi) and radiotherapy (RT) may enhance antitumoral immunity, yet clinical evidence of this interaction in HR+/HER2− metastatic breast cancer (MBC) remains limited. This study evaluates the impact of combined CDKi and stereotactic body radiotherapy (SBRT) on immune biomarkers and treatment response. Methods: We report a case of a 51-year-old woman with oligometastatic HR+/HER2− MBC involving the sacrum. Clinical management included letrozole plus palbociclib and SBRT (30 Gy in 3 fractions). Serial Neutrophil-to-lymphocyte ratio (NLR) measurements, MRI, and PET-CT scans were used to monitor systemic immune modulation and treatment efficacy over a five-year period. Results: Baseline NLR was 1.068. Following four weeks of CDKi, NLR decreased by 44.7% (0.591). Post-SBRT, a further 17.8% reduction was observed (nadir 0.486). Five months post-RT, MRI showed a volumetric increase in sacral lesions despite clinical improvement. Subsequent PET-CT demonstrated a complete metabolic response, confirming the MRI findings as pseudoprogression. As of January 2026, the patient remains in sustained complete metabolic remission. Conclusion: The integration of CDKi and SBRT might induce an immune-mediated antitumoral response, evidenced by dynamic NLR reductions and radiologic pseudoprogression. Multimodal imaging is essential to differentiate immune-mediated swelling from true progression in this setting. Full article

Background/Objectives: To evaluate the prognostic significance of automated, volumetric body composition analysis (BCA) derived from pretreatment thoracic computed tomography (CT) scans in patients with head and neck cancer (HNC). Methods: We retrospectively assessed 160 patients (median age: 63 years; 26.9% women) undergoing primary treatment. BCA quantified various tissue volumes, including bone (B), skeletal muscle (SM), and subcutaneous adipose tissue (SAT). Optimal sex-specific cutoffs for BCA metrics were established via maximally selected log-rank tests. Internal validation of BCA cutoffs was conducted via bootstrap resampling. Kaplan–Meier survival analysis and Cox proportional hazards modeling were used to investigate progression-free survival (PFS). Results: The median PFS for all patients was 51.7 months (95% confidence interval (CI): 31.4–68.8). Among the continuous BCA parameters, only SM/B was significant across the total cohort (hazard ratio (HR): 0.23; 95%CI: 0.12–0.46; p < 0.0001, males (p = 0.0009), females (p = 0.004)). Internal validation of gender-specific cutoffs demonstrated strong-to-intermediate stability for SM/B across both sexes and for SAT/B in males. In contrast, SAT/B exhibited only weak stability among female participants. In univariate PFS analysis, dichotomized SM/B, SAT/B, Union for International Cancer Control (UICC) stage, Eastern Cooperative Oncology Group (ECOG) status, higher body mass index (BMI), normal albumin, and Charlson Comorbidity Index were identified as significant predictors of PFS. Multivariable analysis identified high SM/B (HR: 0.53; 95% CI: 0.3–0.93; p = 0.026) and high SAT/B (HR: 0.58; 95% CI: 0.35–0.95; p = 0.029) as independent prognostic factors, alongside lower UICC stage (p = 0.045) and lower Charlson Comorbidity Index (p = 0.038). Patients with high SM/B and SAT/B ratios had the longest median PFS (65.9 months, 95%CI: 51.7–.), compared to 36.4 months (95%CI: 19.4–.) for high SM/B or SAT/B and 12.6 months (95%CI: 4.2–25.1) for low SM/B and SAT/B (p < 0.0001). Conclusions: Although the BCA parameters SM/B and, to a lesser extent, SAT/B appear to be promising biomarkers, external validation and investigation within well-defined patient subgroups are warranted to establish their generalizability in clinical practice. Full article

Objective: In this study, we aimed to evaluate high-resolution computed tomography (HRCT) features of granulomatous–lymphocytic interstitial lung disease (GLILD) in patients with Common Variable Immunodeficiency (CVID), and to describe a novel imaging feature—termed the “Kebab sign”—as a potential radiologic marker of GLILD. Materials and Methods: We retrospectively reviewed HRCT scans of 15 patients with GLILD diagnosed between 2005 and 2025 at a single institution (seven biopsy-confirmed, eight probable diagnoses based on multidisciplinary consensus). CT patterns were assessed for predominant morphology (nodular, reticular, alveolar, fibrotic), distribution (axial and cranio-caudal), and presence of extra-parenchymal findings. Nodules were characterized by size, density, morphology, and the presence of air bronchograms. The “Kebab sign” was defined as nodules aligned along bronchial structures with associated peribronchial thickening. Results: All patients demonstrated a diffuse nodular pattern, with non-calcified macronodules in 100% and micronodules in 60% of cases. Air bronchograms were present in 87% of macronodules. A peri-bronchovascular distribution with lower lung predominance was observed in the majority of cases. The “Kebab sign” was identified in 87% of patients. Splenomegaly and hilar/mediastinal lymphadenopathy were observed in 75%. In 20% of patients, fibrosing features were also present, particularly in older individuals. Conclusions: HRCT findings of GLILD typically include peri-bronchovascular nodules with lower lobe predominance, typically associated with splenomegaly and mediastinal lymphadenopathy. The newly described “Kebab sign,” reflecting nodular alignment along thickened bronchial structures, may represent a useful imaging clue to support the diagnosis of GLILD. Full article

Background/Objectives: Interstitial lung disease (ILD) is the main thoracic manifestation of connective tissue diseases (CTDs) and is associated with high morbidity and mortality. High-resolution computed tomography (HRCT) of the chest is considered the gold standard imaging method for detecting and accurately characterizing ILD. This study aims to perform longitudinal visual and quantitative analyses of HRCT scans of patients with ILD secondary to CTD (ILD-CTD) and to correlate these findings with clinical outcomes (functional decline and death) in order to identify tomographic prognostic markers. Methods: This retrospective and longitudinal study included 195 patients with CTD who underwent HRCT at baseline and after two follow-ups. Data collected included initial disease extent and subjective impression of progression, as well as quantitative parameters such as lung volume and mean lung density. Forced vital capacity (FVC) and diffusion capacity of carbon monoxide (DLCO) values were also recorded, along with information on patient outcome. Results: Quantitative and visual assessments demonstrated moderate agreement in estimating ILD extent. Variations in lung volume, ground-glass index, pulmonary vascular volume-to-lung volume ratio, and disease extent correlated with subjective perception of disease progression. Lung volume reduction and increased disease extent were associated with FVC decrease at follow-up 1, whereas an increased fibrosis index correlated with reduced FVC at follow-up 2. No quantitative parameter was associated with mortality risk. Conclusions: The results support the potential benefit of using quantitative CT analysis as a complementary tool to pulmonary function tests and visual analysis in the longitudinal evaluation of ILD-CTD. Full article

Background/Objectives: Connective tissue disease-associated interstitial lung disease (CTD-ILD) is linked to substantial morbidity and mortality. While nintedanib (NTB) slows lung function decline in progressive pulmonary fibrosis (PPF), real-world data—particularly regarding radiographic outcomes—remain limited. We aimed to evaluate the real-world effectiveness and tolerability of antifibrotic therapy—predominantly NTB—on radiographic and functional outcomes in a Hungarian CTD-ILD cohort. Methods: We conducted a retrospective observational cohort study including 72 patients with progressive CTD-ILD who initiated antifibrotic therapy at two Hungarian tertiary centers between January 2021 and June 2025. The primary endpoint was the proportion of patients without significant radiographic progression at 6–12 months, based on blinded assessment of paired high-resolution computed tomography (HRCT) scans by two thoracic radiologists. Secondary endpoints included changes in forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) at 6 and 12 months, safety and tolerability, and correlations between lung function and disease-related factors. Results: The cohort comprised systemic sclerosis–ILD (n = 25), rheumatoid arthritis–ILD (n = 23), and other CTD-ILD (n = 24). Radiographic stability was observed in 65.8–78.9% of patients, with improvement most commonly seen in ground-glass opacities, while traction bronchiectasis remained largely unchanged. Radiographic disease extent showed the strongest inverse correlation with baseline FVC and DLCO (p < 0.05). Significant improvements in FVC and DLCO were observed at 6 and 12 months (p < 0.001). Antifibrotic therapy was well tolerated, including in combination with immunosuppressive treatment. Conclusions: These real-world data support the effectiveness and safety of NTB in PPF–CTD-ILD and highlight radiologic disease burden as a key determinant of functional impairment. Full article

Background/Objectives: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a major contributor to morbidity and mortality in RA, yet early recognition remains challenging in routine care. The study aimed to identify clinical factors associated with hrCT-confirmed RA-ILD using a CT-verified case–control design. Methods: A single-center retrospective case–control study was designed to include RA patients who underwent chest hrCT in routine care. Cases were patients with ILD on index hrCT (n = 79) and controls were RA patients with hrCT negative for ILD (n = 59). Data were manually abstracted from clinical interview, laboratory testing, RA activity and structural assessment, respiratory examination, pulmonary function tests (PFT), chest radiography, and hrCT. Predictors were extracted from the 12 months preceding the index scan. Univariate comparisons used nonparametric tests or χ², as appropriate. Prespecified multivariable logistic regression estimated adjusted odds ratios (aORs). Sensitivity analyses included restriction to patients with available pre-index PFT, addition of respiratory examination variables, and a matched conditional logistic regression analysis. Results: In the primary multivariable model, male sex was independently associated with RA-ILD (aOR 5.31, 95% CI 1.91–14.75), and COPD/asthma was also associated (aOR 2.82, 1.05–7.56). Adding dyspnea and Velcro crackles improved discrimination (AUC 0.797 to 0.850); Velcro crackles were independently associated with RA-ILD (aOR 5.11, 1.32–19.73). Findings were directionally similar in sensitivity analyses, though precision decreased in matched models. Conclusions: In this CT-imaged real-world RA cohort, male sex, COPD/asthma, and Velcro crackles were associated with hrCT-confirmed RA-ILD; these findings should be interpreted as preliminary, as they apply to patients selected for imaging and should not be extrapolated to unselected RA populations without validation in larger, multi-center and/or prospective cohorts with systematic ascertainment. Full article

Background: Radiotherapy (RT) combined with androgen deprivation therapy (ADT) is a standard treatment for non-metastatic high-risk (HR) prostate cancer (PC). However, the benefit of elective nodal irradiation (ENI) in clinically node-negative (cN0) patients, although suggested, remains controversial, particularly in the elderly. We report the outcomes of elderly HR PC patients treated with prostate-only RT (PORT) and ADT in a “real-word” setting. Methods: Between 2016 and 2022, 43 consecutive elderly patients (median age 76 years) with HR- or very HR-PC according to NCCN criteria version 1.2026 (cN0, cT3-cT4 and/or ISUP Grade Group 4–5 and/or PSA serum levels at diagnosis ≥ 20 ng/mL) were treated at our institution. All patients were staged with abdominal MRI or CT and bone scan; nineteen patients (44.2%) also underwent 68Ga-PSMA-11 or 18F-fluorocholine PET/CT. All patients received PORT (predominantly moderate hypofractionation, 67.5–70 Gy in 25–28 fractions) and ADT (median duration 24 months). To ensure consistency, all oncological endpoints—Biochemical Failure-Free Survival (BFFS; Phoenix criteria), Disease-Free Survival (DFS), Metastasis-Free Survival (MFS), Prostate Cancer-Specific Survival (PCSS), and Overall Survival (OS)—were calculated from a unified time-zero (initiation of first oncological treatment). DFS was defined as a composite endpoint including biochemical failure, radiological recurrence, or initiation of salvage therapy. Results: at a median follow-up of 60 months, no patient reached the Phoenix threshold, resulting in a 100% 5- and 7-year BFFS. However, 4 patients (9.3%) experienced radiological recurrence detected via PET/CT before reaching the nadir + 2 threshold, yielding an estimated 5-year and 7-year DFS of 94.7% and 71.8%, respectively. The 5- and 7-year MFS was of 97.6% and 88.7%, respectively. Seven deaths occurred, all non-PC related, resulting in a 5-year OS of 86.7% and a Prostate Cancer-Specific Survival of 100%. Gastrointestinal toxicity was notably low (no acute or late G3-G4 events). Conclusions: Our findings suggest that PORT, when combined with long-term ADT and modern staging, provides excellent disease control and a favorable safety profile in elderly HR PC patients. Given the high rate of competing mortality in this population, treatment de-escalation via PORT appears to be a clinically reasonable strategy. These results are hypothesis-generating and warrant validation in prospective randomized trials. Full article

Background and objectives: Early biomarkers that can reliably predict treatment outcomes during CDK4/6 inhibitor therapy remain an unmet clinical need in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer (MBC). Metabolic changes on ^18F-FDG PET/CT may precede radiologic response and provide insight into tumor biology and early treatment resistance. Methods: This two-center retrospective study included 203 patients with HR+/HER2− MBC who received first-line CDK4/6 inhibitors (ribociclib or palbociclib) plus endocrine therapy between 2018 and 2024. Baseline and interim ^18F-FDG PET/CT scans performed after 2–4 cycles were evaluated. Early metabolic response was defined as a ≥30% reduction in SUVmax on the most metabolically active lesion, consistent with PERCIST 1.0. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan–Meier and multivariable Cox models. ROC analysis assessed the discriminative performance of ΔSUVmax for predicting disease progression. Results: Among 203 patients, 153 (75.4%) achieved a ≥30% SUVmax reduction. Responders had significantly longer PFS (median 44.4 vs. 4.8 months; p < 0.001) and OS (median not reached vs. 32.0 months; p < 0.001). Metabolic response remained independently associated with improved PFS (HR 0.24; 95% CI 0.15–0.37; p < 0.001) and OS (HR 0.37; 95% CI 0.20–0.67; p = 0.001) after adjustment for tumor grade, endocrine resistance, and visceral disease involvement. Non-responders demonstrated more aggressive baseline features, including higher rates of liver (34.0% vs. 15.0%) and brain metastasis (10.0% vs. 1.3%), as well as lower progesterone receptor expression (median 30% vs. 60%). Conclusions: Early metabolic response assessed by SUV-max on interim ^18F-FDG PET/CT is independently associated with substantially improved PFS and OS in HR+/HER2− MBC receiving treatment with CDK4/6 inhibitors. Although the predictive accuracy of ΔSUVmax alone was modest, the strong survival gradient suggests meaningful prognostic value. Prospective studies with standardized imaging time points and comprehensive metabolic metrics are warranted to define the role of PET-guided treatment adaptation: Full article

Purpose: To explore the correlation between radiologic patterns on high-resolution computed tomography (HRCT) and circulating biomarkers of inflammation and endothelial activation in patients with COVID-19 pneumonia, with the aim of identifying imaging-biomarker phenotypes that may offer insights for clinical stratification. Materials and Methods: This prospective single-center study included 84 consecutive patients hospitalized with PCR-confirmed SARS-CoV-2 infection and respiratory failure. All underwent baseline HRCT, along with parallel biohumoral profiling, including inflammatory (IL-1Ra, IL-6, IL-10) and endothelial (Angiopoietin-2, sVCAM-1, sE-Selectin) biomarkers. HRCT scans were reviewed for parenchymal and vascular abnormalities (vascular tree-in-bud [TIB], vascular enlargement pattern [VEP]). Semi-quantitative scores were assigned for parenchymal (PS) and vascular (VS) involvement. Results: Patients with higher PS had significantly prolonged hospital stay (35 vs. 17 days; p = 0.014), increased ICU admission rates (68.8% vs. 21.4%; p = 0.003), and elevated serum levels of IL-1Ra, IL-6, and IL-10 (p < 0.05). At multivariable analysis, PS remained independently associated with ICU admission after adjustment for age, inflammatory burden, and comorbidities (p = 0.014). A high VS was associated with significantly increased Angiopoietin-2 levels (p = 0.036), although it did not directly correlate with ICU admission or mortality. A significant positive correlation was observed between PS and VS (r =0.392; p < 0.001). Conclusions: in this study, HRCT-based parenchymal and vascular patterns appear significantly correlated with biological processes occurring in severe COVID-19 pneumonia. These observations, although preliminary, may offer a conceptual basis for future studies exploring radiologic and biomarker-based stratification in severe respiratory infections. Full article

Background: Computed tomography (CT)-derived body composition parameters, including skeletal muscle and fat indices, are prognosticators in oncology. Most studies focus on baseline body-composition parameters; however, changes during treatment may provide better prognostic value. Standardized methods for measuring/reporting these parameters remain limited. Methods: This retrospective study included patients who were treated with immunotherapy for non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), or melanoma between 2017 and 2024 and had technically adequate baseline and follow-up CT scans. Body composition was analyzed using a novel, fully automated software (CompoCT) for L3 slice selection and segmentation. Body composition indices (e.g., skeletal muscle index [SMI]) were calculated by dividing the cross-sectional area by the patient’s height squared. Results: The cohort included 376 patients (mean [SD] age 66.4 [11.4] years, 67.3% male, 72.6% NSCLC, 14.6% RCC, and 12.8% melanoma). During a median follow-up of 21 months, 220 (58.5%) died. Baseline body composition parameters were not associated with mortality, except for a weak protective effect of higher SMI (HR = 0.98, p = 0.043). In contrast, longitudinal decreases were strongly associated with increased mortality. Relative decreases in SMI (HR, 1.17; 95% CI, 1.07–1.27) or subcutaneous fat index (SFI) (HR, 1.11; 95% CI, 1.07–1.15) significantly increased mortality risk. Multivariate models showed similar concordance (0.65) and identified older age, NSCLC tumor type, and relative decreases in SMI and SFI (per 5% units) as independent predictors of mortality. Conclusions: Longitudinal decreases in skeletal muscle and subcutaneous fat were independent predictors of mortality in immunotherapy-treated patients. Automated CT-based body composition analysis may support treatment decisions during immunotherapy. Full article

Background: Sarcopenia is a recognized adverse prognostic factor in many cancers and can be reliably assessed using computed tomography (CT) scans. Its prognostic value in bladder cancer patients undergoing neoadjuvant chemotherapy remains underexplored. This study aimed to assess sarcopenia’s impact on survival and compare different measurement thresholds. Methods: We conducted a retrospective multicenter study including patients with invasive urothelial carcinoma treated with neoadjuvant chemotherapy followed by cystectomy between 2015 and 2021. Sarcopenia was assessed by measuring the Skeletal Muscle Index on CT scans before chemotherapy (BC) and prior to surgery (BS). The primary endpoint was overall survival. Secondary endpoints included progression-free survival (PFS), pathological complete response (pCR), and treatment-related complications. Results: Seventy-four patients were included, the majority receiving the MVAC regimen (71.7%). Forty percent of patients achieved a pCR, 35% experienced disease recurrence, and the median PFS was 25 months. Sarcopenia was observed in 27% of patients BC and in 39% BS. Sarcopenia was associated with an increased risk of all-cause mortality: BC according to the definition by Martin et al. (HR 3.38; 95% CI [1.25–9.12]; p = 0.016) and Fearon et al. (HR 4.03; 95% CI [1.13–14.3]; p = 0.031); and BS according to Martin et al. (HR 3.7; 95% CI [1.12–12.2]; p = 0.032) and Fearon et al. (HR 6.08; 95% CI [1.48–24.9]; p = 0.012). Sarcopenia was an independent risk factor of shorter PFS. Conclusions: Sarcopenia represent an independent and reproducible prognostic factor for mortality in patients with bladder cancer. The study is the first study to compare threshold values at different time points. Full article

Background and Objectives: This study aimed to evaluate the prognostic impact of baseline body composition measurements and changes in muscle and adipose tissue during treatment on overall survival (OS) in metastatic non-small cell lung cancer (NSCLC) patients treated with nivolumab. Materials and Methods: Eighty-eight metastatic NSCLC patients who were initiated on nivolumab between January 2022 and December 2024 were retrospectively analyzed. Body composition parameters were derived from baseline and 3-month ¹⁸F-FDG PET/CT scans at the L3 level, including psoas muscle index (PMI), skeletal muscle index (SMI), intramuscular adipose content (IMAC), and subcutaneous fat density (SFD). Treatment-related changes in body composition were evaluated, and survival analyses were performed using Kaplan–Meier estimates and Cox regression models. Results: Overall, 34.1% (n = 30) of patients were classified as sarcopenic. Median OS was significantly longer in non-sarcopenic patients (19 months vs. 5 months, p < 0.001). In univariate analysis, older age, higher comorbidity burden, liver metastasis, baseline sarcopenia, and adverse treatment-related changes in muscle and nutritional parameters were found to be associated with OS. In multivariate analysis, only unfavorable changes in skeletal muscle (ΔSMI; HR 3.39, p = 0.003) and subcutaneous fat radiodensity (ΔSFD; HR 2.45, p = 0.02) remained independent adverse prognostic factors. Baseline body composition parameters did not maintain their independence in multivariate models. Conclusions: Our study demonstrates that muscle loss or insufficient gain and unfavorable changes in subcutaneous fat radiodensity during nivolumab treatment more strongly predict overall survival compared to baseline measurements. These findings highlight the clinical importance of monitoring dynamic body composition throughout treatment, rather than static assessments, in NSCLC patients receiving immunotherapy. Full article

Background and Objectives: COVID-19 is an infection caused by the SARS-CoV-2 coronavirus that may develop several complications. Interstitial lung disease (ILD) is the major long-term complication of COVID-19 disease leading to progressive lung fibrosis and reduced respiratory function. The aim of this narrative review is to provide an updated overview of post-COVID-19 ILD by examining research publications and clinical guidelines selected from PubMed, Web of Science, and major respiratory medicine journals from 2020 to 2025. Methods: ILDs are diagnosed by medical history, physiological examination, pulmonary function tests, and chest X-ray or high-resolution computed tomography (HRCT) scan. Lung biopsy, especially cryobiopsy or video-assisted thoracoscopic (VATS) biopsy, can be performed to define histological patterns and confirm the diagnosis. Results: Post-COVID-19 ILD is a chronic condition characterized by long-term respiratory symptoms, radiological findings, and reduced lung function. Fibrotic injury is a consequence of the initial infection and could be influenced by persistent inflammation and dysregulated tissue repair. Risk factors include severe acute illness, advanced age, male sex, and smoking. Clinical course and prognosis of post-COVID-19 ILD is uncertain, as most patients experience gradual improvement or stability, whereas others develop progressive lung function decline. Treatment of post-COVID-19 ILD is not presently defined by guidelines but comprises corticosteroids, antifibrotics (including new drugs such as nerandomilast), supportive oxygen, pulmonary physiotherapy rehabilitation, smoking cessation, and vaccination. Conclusions: ILD represents a significant long-term complication of COVID-19 infection. Further investigations are required to better understand its pathophysiology and clinical management. As research progresses, more effective diagnostic and therapeutic strategies are expected to emerge. Full article

Background: Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) caused by repeated exposure to inhaled antigens in susceptible subjects. High-resolution computed tomography (HRCT) of the lungs is the leading diagnostic method for ILDs, but in some cases HRCT findings are not sufficient to distinguish HP and other ILDs, particularly, fibrotic HP (fHP) and usual interstitial pneumonia (UIP). Objective: The aim of this study was to develop HRCT criteria to diagnose fHP in patients with a UIP-like pattern. Methods: In this retrospective study, we analyzed HRCT scans of patients with fHP and a UIP-like pattern who underwent lung biopsy, and patients with idiopathic pulmonary fibrosis (IPF) and a UIP pattern in HRCT. Results: We included 51 patients with confirmed fHP and 24 patients with IPF/UIP in the analysis. IPF/UIP patients were older, were prevalently males, and did not have any systemic autoimmune diseases or risk factors for other ILDs. fHP patients were younger, with an equal number of males and females, and were more likely to be exposed to environmental antigens. HRCT abnormalities in the fHP group predominated in the lower lung areas or were diffuse in axial scans, whereas IPF/UIP patients mostly demonstrated a diffuse craniocaudal distribution and subpleural axial predominance. Centrilobular nodules and mosaic attenuation were present significantly more often in the fHP group; honeycombing, traction bronchiectasis, and emphysema prevailed in IPF/UIP patients. In the logistic regression analysis, patients with fHP and IPF/UIP differed in the presence of centrilobular nodules, honeycombing, and in both craniocaudal and axial distributions of HRCT abnormalities. In the ROC analysis, the combination of centrilobular nodules, honeycombing, and diffuse axial and craniocaudal distributions can predict the diagnosis of fHP (AUC, 0.953 ± 0.022; 95%CI, 0.910–0.995; p < 0.001). Mosaic attenuation and reticulation did not change the probability of fHP. Conclusions: The most significant HRCT features of fHP compared to the UIP pattern were centrilobular nodules, honeycombing, and a diffuse axial and craniocaudal distribution of abnormal findings. Reticulation, mosaic attenuation, and GGO do not increase the probability of fHP. Full article