Rechallenge in idiosyncratic drug-induced liver injury: an analysis of cases in two large prospective registries according to existing definitions.

INTRODUCTION: Data on positive rechallenge in idiosyncratic drug-induced liver injury (DILI) are scarce. We aim to analyse the clinical presentation, outcome and drugs associated with positive rechallenge in two DILI registries. METHODS: Cases from the Spanish and Latin American DILI registries were included. Demographics, clinical characteristics and outcome of cases with positive rechallenge according to CIOMS/RUCAM and current definitions were analysed. RESULTS: Of 1,418 patients with idiosyncratic DILI, 58 cases had positive rechallenge (4.1%). Patients with positive rechallenge had shorter duration of therapy (p=0.001) and latency (p=0.003). In patients with rechallenge, aspartate transaminase levels were increased (p=0.026) and showed a prolonged time to recovery (p=0.020), albeit no differences were seen in terms of fatal outcomes. The main drug implicated in rechallenge was amoxicillin-clavulanate (17%). The majority of re-exposure events were unintentional (71%). Using both existing definitions of positive rechallenge, there were four cases which exclusively fulfilled the current criteria and five which only meet the historical definition. All cases of positive rechallenge, irrespective of the pattern of damage, fulfilled the criteria of either alanine transaminase (ALT) ≥3 times the upper limit of normal (ULN) and/or alkaline phosphatase (ALP) ≥2 times ULN. CONCLUSIONS: Episodes of rechallenge were characterised by shorter duration of therapy and latency, and longer time to resolution, but did not show an increased incidence of fatal outcome. Based on our findings, ALT ≥3 times ULN and/or ALP ≥2 times ULN, regardless of the pattern of damage, is proposed as a new definition of rechallenge in DILI.

Prótesis mitral mecánica disfuncionante: cuando el trombo sobre pannus dificulta el diagnóstico / Dysfunctioning mechanical mitral valve prosthesis: When thrombus over pannus makes hinders diagnosis

La obstrucción de una válvula protésica es una complicación rara pero que puede ser letal. Las causas más frecuentes son la formación de trombos y pannus, en ausencia de datos infecciosos. El diagnóstico no siempre es sencillo recurriendo a la realización de tomografía computarizada (TC) cardiaca, y en el 46-85% de los casos coexisten trombo y pannus, por lo que el diagnóstico se complica. Un diagnóstico rápido es esencial para evitar un desenlace fatal de esta patología, cuya mortalidad, a pesar de un tratamiento correcto, es elevada.(AU)

Prosthetic valve obstruction is a rare but potentially lethal complication. The most frequent causes are thrombus and pannus formation, in the absence of infectious data. Diagnosis is not always easy using cardiac CT scanning and in 46-85% of cases thrombus and pannus coexist, complicating the diagnosis. A rapid diagnosis is essential to avoid a fatal outcome of this pathology whose mortality, despite correct treatment, is high.(AU)

Dysfunctioning mechanical mitral valve prosthesis: When thrombus over pannus makes hinders diagnosis.

Prosthetic valve obstruction is a rare but potentially lethal complication. The most frequent causes are thrombus and pannus formation, in the absence of infectious data. Diagnosis is not always easy using cardiac CT scanning and in 46%-85% of cases thrombus and pannus coexist, complicating the diagnosis. A rapid diagnosis is essential to avoid a fatal outcome of this pathology whose mortality, despite correct treatment, is high.

Effect of cationic surfactant on the physicochemical and antibacterial properties of colloidal systems (emulsions and microemulsions).

Colloidal systems have been used to encapsulate, protect and release essential oils in mouthwashes. In this study, we investigated the effect of cetylpyridinium chloride (CPC) on the physicochemical properties and antimicrobial activity of oil-in-water colloidal systems containing tea tree oil (TTO) and the nonionic surfactant polysorbate 80. Our main aim was to evaluate whether CPC could improve the antimicrobial activity of TTO, since this activity is impaired when this essential oil is encapsulated with polysorbate 80. These systems were prepared with different amounts of TTO (0-0.5% w/w) and CPC (0-0.5% w/w), at a final concentration of 2% (w/w) polysorbate 80. Dynamic light scattering (DLS) results revealed the formation of oil-swollen micelles and oil droplets as a function of TTO concentration. Increases in CPC concentrations led to a reduction of around 88% in the mean diameter of oil-swollen micelles. Although this variation was of only 20% for the oil droplets, the samples appearance changed from turbid to transparent. The surface charge of colloidal structures was also markedly affected by the CPC as demonstrated by the transition in zeta potential from slightly negative to highly positive values. Electron paramagnetic resonance (EPR) studies showed that this transition is followed by significant increases in the fluidity of surfactant monolayer of both colloidal structures. The antimicrobial activity of colloidal systems was tested against a Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureaus) bacteria. Our results revealed that the inhibition of bacterial growth is observed for the same CPC concentration (0.05% w/w for E. coli and 0.3% w/w for S. aureus) regardless of TTO content. These findings suggest that TTO may not act as an active ingredient in polysorbate 80 containing mouthwashes.

Temporary work disability following trapezial resection and suspension arthroplasty for thumb carpometacarpal osteoarthritis. / Incapacidad laboral temporal tras cirugía de rizartrosis mediante trapecectomía y artroplastia de suspensión con sutura de alta resistencia.

PURPOSE: The aim of this study is to assess the time to return to work (TRW) in patients undergoing trapezial resection using the Mini TightRope® system at our center and to investigate factors that might delay return to work following this surgery. MATERIAL AND METHODS: A retrospective study was conducted on patients who underwent Trapezial resection and suspensionplasty using the Mini TightRope® system between 2015 and 2016, with a minimum one-year follow-up. Telephone interviews were conducted along with a review of medical records and radiology reports, as well as temporary work disability documents, collecting epidemiological and occupational data. Groups were compared based on age, gender, dominant hand, biomechanical occupational requirements of the patients, and whether they had experienced prior temporary work disability. RESULTS: A total of 36 patients (29 women and 7 men) with an average age of 55.7 years were included. The median time to return to work was 126 days. Self-employed workers re-entered the workforce 72 days earlier on average; workers who had experienced prior temporary work disability had a greater total temporary work disability duration and took 91 days longer to return to work compared to those who had not. CONCLUSIONS: Patients employed by others and those who had experienced prior temporary work disability before the surgery had longer temporary work disability periods. In our study, no differences were observed based on gender, dominant hand, or biomechanical work demands of the intervened patients.

Radiological-pathological correlation in diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH): imaging and histopathology.

AIM: To review histologically confirmed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) cases and carry out a detailed pathological-radiological correlation to see if computed tomography (CT) can be used to confidently identify DIPNECH. MATERIALS AND METHODS: Twenty-three histologically confirmed DIPNECH patients in the shared database of two NHS Trusts were reviewed. CT images were reviewed by two independent radiologists, each of them with >10 years of experience in thoracic imaging. All histological specimens were reviewed by a single pathologist with >25 years of experience. The diagnosis of DIPNECH was made according to the current World Health Organization (WHO) definition included in the WHO 2015 classification of pulmonary tumours. The results on histology were compared to the presence of nodules and air trapping on CT. Demographic information and, when available, molecular imaging studies and pulmonary function tests were also considered. RESULTS: There are prototypal clinical and radiological findings reflecting the presence of underlying histological DIPNECH: middle-aged women with multiple small and scattered nodules due to the clustering and proliferation of neuroendocrine cells. At least one larger, dominant, lung nodule reflecting a carcinoid tumour is very common and mosaic attenuation/air trapping is seen approximately in 50% of cases in inspiratory scans. Airflow obstruction is rarely associated with histological bronchial or peribronchial fibrosis, which suggests other mechanisms must be involved in its development. CONCLUSION: CT can be used to predict pathological DIPNECH in the appropriate clinical setting. It is important to consider DIPNECH to avoid overdiagnosis of more sinister conditions such as lung cancer or metastases.

Computed diffusion-weighted imaging in patients with transient neurovascular symptoms with and without ischemic infarction.

PURPOSE: Detection of ischemic lesions in patients with transient neurovascular symptoms is relevant for the estimation of the risk of a subsequent stroke and etiological classification. To improve detection rates, different technical approaches have been used, such as diffusion-weighted imaging (DWI) with high b-values or higher magnetic field strength. Here, we sought to investigate the value of computed DWI (cDWI) with high b-values in these patients. METHODS: From an MRI report database we identified patients with transient neurovascular symptoms who underwent repeated MRI including DWI. cDWI was calculated with a monoexponential model with high b-values (2000, 3000, and 4000 s/mm2) and compared to the routinely used standard DWI with regard to presence of ischemic lesions and lesion detectability. RESULT: Overall 33 patients with transient neurovascular symptoms (71 [IQR 57-83.5] years; 21 [63.6%] male) were included. On DWI, acute ischemic lesions were observed in 22 (78.6%). Acute ischemic lesions were observed in 17 (51.5%) patients on initial DWI, and in 26 (78.8%) patients on follow-up DWI. Lesion detectability was rated significantly better on cDWI at 2000s/mm2 compared to standard DWI. In 2 (9.1%) patients, cDWI at 2000s/mm2 revealed an acute ischemic lesion proven on follow-up standard DWI which was not detected with certainty on the initial standard DWI. CONCLUSION: cDWI might be a valuable addition to routinely acquired standard DWI in patients with transient neurovascular symptoms since its use might result in improved ischemic lesion detection. A b-value of 2000s/mm2 seems most promising for clinical practice.

XV Reunión Post-ECTRIMS: revisión de las novedades presentadas en el Congreso ECTRIMS 2022 (II) / 15th Post-ECTRIMS Meeting: a review of the latest developments presented at the 2022 ECTRIMS Congress (Part II)

Introducción: El 4 y el 5 de noviembre se celebró en Madrid la Reunión Post-ECTRIMS, en la que neurólogos expertos en esclerosis múltiple resumieron las principales novedades presentadas en el congreso de ECTRIMS 2022, celebrado entre el 26 y el 28 de octubre en Ámsterdam. Objetivo: Sintetizar las ponencias que tuvieron lugar en la Reunión Post-ECTRIMS, en un artículo desglosado en dos partes. Desarrollo: En esta segunda parte, se presentan las novedades sobre las estrategias terapéuticas de escalado y desescalado de los tratamientos modificadores de la enfermedad (TME), cuándo y a quién iniciar o cambiar a TME de alta eficacia, la definición de fracaso terapéutico, la posibilidad de tratar el síndrome radiológico asilado, el futuro del tratamiento personalizado y la medicina de precisión, la eficacia y seguridad del autotrasplante de células madre hematopoyéticas, diferentes aproximaciones en el diseño de ensayos clínicos y en las medidas de resultados para evaluar TME en fases progresivas, retos en el diagnóstico y tratamiento del deterioro cognitivo, y tratamiento en situaciones especiales (embarazo, comorbilidad y personas mayores). Además, se muestran los resultados de algunos de los últimos estudios realizados con cladribina oral y evobrutinib presentados en el ECTRIMS 2022.(AU)

Introduction: On 4 and 5 November 2022, Madrid hosted the 15th edition of the Post-ECTRIMS Meeting, where neurologists specialised in multiple sclerosis outlined the latest developments presented at the 2022 ECTRIMS Congress, held in Amsterdam from 26 to 28 October. Aim: To synthesise the content presented at the 15th edition of the Post-ECTRIMS Meeting, in an article broken down into two parts. Development: This second part describes the new developments in terms of therapeutic strategies for escalation and de-escalation of disease-modifying therapies (DMT), when and in whom to initiate or switch to highly effective DMT, the definition of therapeutic failure, the possibility of treating radiologically isolated syndrome and the future of personalised treatment and precision medicine. It also considers the efficacy and safety of autologous haematopoietic stem cell transplantation, different approaches in clinical trial design and outcome measures to assess DMT in progressive stages, challenges in the diagnosis and treatment of cognitive impairment, and treatment in special situations (pregnancy, comorbidity and the elderly). In addition, results from some of the latest studies with oral cladribine and evobrutinib presented at ECTRIMS 2022 are shown.(AU)

XV Reunión Post-ECTRIMS: revisión de las novedades presentadas en el Congreso ECTRIMS 2022 (I) / 15th Post-ECTRIMS Meeting: a review of the latest developments presented at the 2022 ECTRIMS Congress (Part I)

Introducción: El 4 y el 5 de noviembre se celebró en Madrid la XV edición de la Reunión Post-ECTRIMS, donde neurólogos expertos en esclerosis múltiple (EM) resumieron las principales novedades presentadas en el congreso de ECTRIMS 2022, celebrado en Ámsterdam entre el 26 y el 28 de octubre. Objetivo: Sintetizar las ponencias que tuvieron lugar en la Reunión Post-ECTRIMS, en un artículo desglosado en dos partes. Desarrollo: En esta primera parte se presentan los primeros eventos involucrados en el inicio de la EM, la implicación de los linfocitos y la migración de células del sistema inmunitario hacia el sistema nervioso central. Se describen los biomarcadores emergentes en fluidos corporales y los hallazgos de imagen que permiten predecir la evolución de la enfermedad, y que resultan útiles en el diagnóstico diferencial de la EM. También se exponen los avances en las técnicas de imagen que, junto con un mayor conocimiento de los agentes involucrados en los procesos de desmielinización y remielinización, proporcionan una base para abordar la remielinización en el entorno clínico. Por último, se repasan los mecanismos desencadenantes de la reacción inflamatoria y la neurodegeneración implicados en la patología de la EM.(AU)

Introduction: On 4 and 5 November 2022, Madrid hosted the 15th edition of the Post-ECTRIMS Meeting, where neurologists specialised in multiple sclerosis (MS) outlined the most relevant novelties presented at the 2022 ECTRIMS Congress, held in Amsterdam from 26 to 28 October. Aim: To synthesise the content presented at the 15th edition of the Post-ECTRIMS Meeting, in an article broken down into two parts. Development: In this first part, the initial events involved in the onset of MS, the role played by lymphocytes and the migration of immune system cells into the central nervous system are presented. It describes emerging biomarkers in body fluids and imaging findings that are predictive of disease progression and useful in the differential diagnosis of MS. It also discusses advances in imaging techniques which, together with a better understanding of the agents involved in demyelination and remyelination processes, provide a basis for dealing with remyelination in the clinical setting. Finally, the mechanisms triggering the inflammatory reaction and neurodegeneration involved in MS pathology are reviewed.(AU)

Review of the Greening Reaction by Thermal Treatment: New Insights Exploring the Structural Implications of Myoglobin.

Myoglobin is the main factor responsible for muscle pigmentation in tuna; muscle color depends upon changes in the oxidative state of myoglobin. The tuna industry has reported muscle greening after thermal treatment involving metmyoglobin (MetMb), trimethylamine oxide (TMAO), and free cysteine (Cys). It has been proposed that this pigmentation change is due to a disulfide bond between a unique cysteine residue (Cys10) found in tuna MetMb and free Cys. However, no evidence has been given to confirm that this reaction occurs. In this review, new findings about the mechanism of this greening reaction are discussed, showing evidence of how free radicals produced from Cys oxidation under thermal treatment participate in the greening of tuna and horse muscle during thermal treatment. In addition, the reaction conditions are compared to other green myoglobins, such as sulfmyoglobin, verdomyoglobin, and cholemyoglobin.

Adult Diaphorina citri Biocontrol Using Hirsutella citriformis Strains and Gum Formulations.

Hirsutella citriformis Speare is the only entomopathogenic fungus that has been applied to control the hemipteran Diaphorina citri Kuwayama. However, the use of available commercial products under field conditions is limited due to conidia's shelf life and short environmental persistence. We have previously reported the citrus psyllid D. citri adults' biocontrol potential using H. citriformis strains. The aim of the present study was to evaluate different formulations based on H. citriformis (OP-Hir-3, OP-Hir-10, and OP-Hir-12 strains) conidia and gums as additives to improve D. citri adults' biocontrol, under laboratory, greenhouse, and field conditions, using Hirsutella gums as conidia stabilizers to improve their viability under environmental drought conditions and as insecticide. Laboratory bioassay results showed that the highest (p < 0.05) D. citri mortality was achieved using FOP-Hir-10GH (63.5%), followed by the Hirsutella gum control (42.2%). Under greenhouse conditions, adults' mortality reached up to 84.6% with FOP-Hir-12 and 49.0% with Hirsutella gum. In addition, we applied H. citriformis formulations under field conditions in a commercial citrus grove located in Tecomán, Colima, México, at 21.5 °C and 73.3% relative humidity (RH) in March and 25.7 °C and 72.5% RH in October 2022 and observed 67.3% and 94.0% mortality of D. citri adults, respectively. Hirsutella gum alone showed significant insecticidal activity against D. citri adults. In conclusion, this study demonstrated that Hirsutella gum functioned as additive to H. citriformis conidia formulations, improving D. citri adults' mortality and showing potential for this pest biocontrol in citrus orchards.

Clinical Features and Voxel-Based-Symptom-Lesion Mapping of Silent Aspiration in Acute Infratentorial Stroke.

Post-stroke dysphagia (PSD) is a severe and common complication after ischemic stroke. The role of silent aspiration as an important contributing factor in the development of a dysphagia-associated complications, in particular aspiration-associated pneumonia has been insufficiently understood. The aim of this study was to investigate the characteristics and risk factors of silent aspiration in patients with acute infratentorial stroke by FEES and to identify culprit lesions in stroke patient with a high risk of silent aspiration via voxel-based-symptom-lesion mapping (VBS/ML). This study is a retrospective observational study based on a prospectively collected FEES and stroke database. Consecutive patient cases with acute ischemic infratentorial stroke and FEES examination between 2017 and 2022 were identified. Group allocation was performed based on PAS scores. Imaging analysis was performed by manual assignment and by VBS/ML. Group comparisons were performed to assess silent aspiration characteristics. Binary logistic regression analysis was performed to determine if baseline clinical, demographic, and imaging parameters were helpful in predicting silent aspiration in patients. In this study 84 patient cases with acute infratentorial stroke who underwent FEES examination were included. Patients were moderately affected at admission (mean NIH-SS score at admission 5.7 SD ± 4.7). Most lesions were found pontine. Overall 40.5% of patients suffered from silent aspiration, most frequently in case of bilateral lesions. Patients with silent aspiration had higher NIH-SS scores at admission (p < 0.05), had a more severe swallowing disorder (p < 0.05) and were 4.7 times more likely to develop post-stroke pneumonia. Patients who underwent FEES examination later than 72 h after symptom onset were significantly more likely to suffer from silent aspiration and to develop pneumonia compared to patients who underwent FEES examination within the first 72 h (p < 0.05). A binary logistic regression model identified NIH-SS at admission as a weak predictor of silent aspiration. Neither in manual assignment of the lesions to brain regions nor in voxel-wise statistic regression any specific region was useful in prediction of silent aspiration. Silent aspiration is common in patients with infratentorial stroke and contributes to the risk for pneumonia. Patients with silent aspiration are more severely affected by stroke, but cannot reliably be identified by NIH-SS at admission or lesion location. Patients suffering from acute infratentorial stroke should been screened and examined for PSD and silent aspiration.

Binding Specificity of a Novel Cyclo/Maltodextrin-Binding Protein and Its Role in the Cyclodextrin ABC Importer System from Thermoanaerobacterales.

Extracellular synthesis of functional cyclodextrins (CDs) as intermediates of starch assimilation is a convenient microbial adaptation to sequester substrates, increase the half-life of the carbon source, carry bioactive compounds, and alleviate chemical toxicity through the formation of CD-guest complexes. Bacteria encoding the four steps of the carbohydrate metabolism pathway via cyclodextrins (CM-CD) actively internalize CDs across the microbial membrane via a putative type I ATP-dependent ABC sugar importer system, MdxEFG-(X/MsmX). While the first step of the CM-CD pathway encompasses extracellular starch-active cyclomaltodextrin glucanotransferases (CGTases) to synthesize linear dextrins and CDs, it is the ABC importer system in the second step that is the critical factor in determining which molecules from the CGTase activity will be internalized by the cell. Here, structure-function relationship studies of the cyclo/maltodextrin-binding protein MdxE of the MdxEFG-MsmX importer system from Thermoanaerobacter mathranii subsp. mathranii A3 are presented. Calorimetric and fluorescence studies of recombinant MdxE using linear dextrins and CDs showed that although MdxE binds linear dextrins and CDs with high affinity, the open-to-closed conformational change is solely observed after α- and ß-CD binding, suggesting that the CM-CD pathway from Thermoanaerobacterales is exclusive for cellular internalization of these molecules. Structural analysis of MdxE coupled with docking simulations showed an overall architecture typically found in sugar-binding proteins (SBPs) that comprised two N- and C-domains linked by three small hinge regions, including the conserved aromatic triad Tyr193/Trp269/Trp378 in the C-domain and Phe87 in the N-domain involved in CD recognition and stabilization. Structural bioinformatic analysis of the entire MdxFG-MsmX importer system provided further insights into the binding, internalization, and delivery mechanisms of CDs. Hence, while the MdxE-CD complex couples to the permease subunits MdxFG to deliver the CD into the transmembrane channel, the dimerization of the cytoplasmatic promiscuous ATPase MsmX triggers active transport into the cytoplasm. This research provides the first results on a novel thermofunctional SBP and its role in the internalization of CDs in extremely thermophilic bacteria.

TC torácica en espiración. Cuándo la hago y cómo la interpreto / Expiratory CT scan: When to do it and how to interpret it

La TC torácica en espiración es una técnica complementaria de la inspiración que aporta valiosa información fisiológica y puede ser más sensible que las pruebas de función respiratoria para detectar atrapamiento aéreo. Tiene múltiples indicaciones, entre las más frecuentes están la enfermedad obstructiva de la vía aérea producida por bronquiolitis obliterante, asma, síndrome de Swyer-James, traqueomalacia, neumonitis por hipersensibilidad o sarcoidosis. En alguna de ellas, como la bronquiolitis obliterante, la TC espiratoria puede ser la única técnica de imagen que detecta alteraciones en las fases iniciales. Si queremos que sea de utilidad diagnóstica, hay que asegurarse de que el estudio tenga calidad suficiente. Para ello se recomienda explicar al paciente en qué consiste la prueba, emplear instrucciones precisas y realizar un breve entrenamiento antes de iniciar la adquisición. En este trabajo sugerimos estrategias para optimizar la técnica y proponemos un algoritmo para interpretar los hallazgos radiológicos en el contexto de la patología obstructiva pulmonar.(AU)

Expiratory CT scan is a complementary technique of inspiratory CT that provide valuable physiological information and may be more sensitive to detect air trapping than pulmonary function tests. It is useful in many obstructive airway diseases, including obliterative bronchiolitis, asthma, Swyer-James syndrome, tracheomalacia, hypersensitivity pneumonitis and sarcoidosis. In obliterative bronchiolitis, expiratory CT scan may be the only imaging technique that shows abnormalities in the early phase of disease. In order to obtain a good quality study, we should explain the procedure to the patient, use precise instructions and do some practice before image acquisition. Here we describe strategies to optimize the technique and propose an algorithm that help in interpretation of imaging findings in patients with obstructive airway disease.(AU)

Application of participatory design and open source to a sustainable proposal for sorption reactor design.

An implementation proposal that seeks to globalize the scope of the sustainable technologies developed in the University laboratories is presented. This approach uses the generation of triple-impact projects placing people at the center of technological development to bring technical and scientific knowledge into a service design oriented to global sustainable solutions. This research is an approach to what a hub for scientific research, technological implementation, and human needs would look like by designing common environments in which to interact and expand knowledge in an iterated way through the experience of all the actors involved in technological implementation. As a control case, a new technology developed at the Universidad de Buenos Aires, consisting of using sustainable materials as tubular reactor fillers for water treatment was chosen. Based on data obtained within the framework of a University extension project, in which the water quality diagnosis for human consumption was carried out and cross-examined with the mathematical analysis of sorption, design parameters of the reactor, participatory design, and open source concepts application, different virtual environments were generated with distinct objectives: i) open design environment: publishing and mapping of installed sorption reactors, reactor model plans, and useful information related to drinking water quality (aimed at contributors of the open source design environment); ii) platform for academic actors linking: connecting data between prototyping lab for participatory design of sorption reactors (aimed at university research users); iii) information disclosure page: space where the implemented technology impact is displayed and shows options to contact researchers and request a reactor design diagnosis for another community (aimed at beneficiary users). A technological service designed to link the University with the community was proposed, by resolving one of the main gaps related to the possibility for communities to access public financing for self-managed improvement projects, increasing the appropriation of the adopted technology and democratizing public investment, making it sustainable over time.

Expiratory CT scan: When to do it and how to interpret it.

Expiratory CT scan is a complementary technique of inspiratory CT that provide valuable physiological information and may be more sensitive to detect air trapping than pul-monary function tests. It is useful in many obstructive airway diseases, including obliterative bronchiolitis, asthma, Swyer-James syndrome, tracheomalacia, hypersensitivity pneumonitis and sarcoidosis. In obliterative bronchiolitis, expiratory CT scan may be the only imaging technique that shows abnormalities in the early phase of disease. In order to obtain a good quality study, we should explain the procedure to the patient, use precise instructions and do some practice before image acquisition. Here we describe strategies to optimize the techni-que and propose an algorithm that help in interpretation of imaging findings in patients with obstructive airway disease.